SHAPA Supplement Winter 2019

Winter 2019

NEWS

Introduction

By Ian Birkinshaw, General Secretary - Solids Handling & Processing Association

in Numbers The Solids Handling & Processing Association has now nearly completed its fourth decade of continuous progress from its initial start in 1981 with only 7 companies it has grown to well over 100 organisations, all focusing on providing the best possible solutions for all aspects of solids and bulk handling. Thank you and congratulations to all those who have been involved in making SHAPA the success it is today.

There is clearly something driving this success and that is, or more correctly, they are the end user customers who rely on the expertise and competence of their supply chain. The benefits of SHAPA membership by acknowledged industry experts and suppliers combine to offer proper long-term peace of mind to plant owners and operators.

Well, it is very easy to become inwardly focused, but the risk is losing sight of the main purpose of our very reason for being. Perhaps SHAPA exists solely for the benefit and development of its members, this would be an overstatement and also missing the crucial point.

So, what makes SHAPA unique and what is the real purpose of the organisation, how has it survived growth, recession and successive changes imposed by successive governments over the intervening years?

56 | SHAPA Newsletter

To aid end users further in their selection of the right equipment for their installation, SHAPA have developed a Total Cost of Ownership paper, the aim of this document is to provide a framework to enable all stakeholders to qualify the whole lifetime value of equipment so that this can be compared against suppliers rather than just being compared on the basis of the initial capital cost. This document is free to download from the SHAPA website We are generally all in agreement that the application of science serves more reliably and predictably than the so-called black art which for a long time characterised the powder and

granular material handling and processing industry. Fortunately, collective education, technical knowledge and experience have come together to provide a soundly based scientific approach to these disciplines.

It is very difficult to achieve all of this in isolation however large a company might be. So, by sharing practical and theoretical engineering knowledge amongst like-minded companies through technical papers and training events, quicker progress is possible, guesswork may be eliminated, and industry standard solutions can be developed, upon which individual member companies may build their advantages and inject cutting edge ingenuity.

Introduction Larger installations may be overseen by project engineering companies, project managers or consultants who require a complete set of equipment, each of which work in isolation and are ultimately combined together to form one complete holistic solution that performs to the overall project specification. These individual items of equipment are quite often procured from several companies with individual expertise to provide the overall solution for the end user.

Compatibility of equipment from intake points, batch storage containers, process equipment through to dust-free bagging and out-loading require co-operation throughout the process. This means complete trust amongst the manufacturers and suppliers, knowledge of the machine functions including the required inputs and outputs upstream or downstream from any piece of process equipment and in particular how one element could interact with the next in normal and abnormal conditions.

In addition, controls and safety protocols must recognise and take account of the operating conditions of the surrounding environment, plant and equipment. Not until all the finest detail is taken into account can all the information used to provide the most effective long-term solution for the end user.

All of this is clearly desirable and indeed essential to maintain the end user in a competitive position in his own marketplace. Furthermore, there should remain scope for later improvements as new techniques, advances in technology and better production equipment are developed and become available. All of this may be more readily achieved if the specialist companies involved can work together successfully, even better if they know each other and have worked together previously. The success any technically demanding, project can be increased still further by being safe in the knowledge that their selected manufacturers and suppliers can demonstrate that they have access to all the best relevant technical, commercial and legal knowledge.

With the current push to increase the productivity of manufacturing by the government, many end user industries are turning to use automated bulk storage, handling and

processing equipment. In order to cope with the myriad of powder and granular material types, exhibiting truly diverse properties at all stages of storage and processing is the real reason that solids and bulk handling companies join a technically based trade association and the only major UK based trade association serving the whole range of our industries is SHAPA. Like any company, club or association, SHAPA is a made up of a team of committed individuals, who give their time voluntarily and enthusiastically to run the General Council and the two sub-committees looking after the marketing and technical activities.

These groups are continually driving progress to enable all member companies to have the tools at hand to enable them to compete. As we look forward towards our 40th Anniversary the drive for innovation and more science to solids and bulk handling knowledge is undiminished and at SHAPA we have teamed up with an innovation funding partner to allow members to unlock funds from R&D tax credits and Patent box initiatives details can be found on the SHAPA website on the Innovation funding page .

SHAPA is about to launch the annual Solids Handling Industry Awards which recognise the successes and innovations within our industry. The awards open on the 1st December 2019 and close on the 29th February 2020. With 2020 being a leap year we can look forward to a leap forward in innovation and knowledge. The award categories for the awards are, Innovation, Export, Newcomer and Company of the year.

Speaking of newcomers, we welcome

our next Arkwright Scholar Theo Cains to the association, our last Scholar, Georgina Edwards has now moved on to university and we wish her well in her future studies and career selection.

In addition to meetings and training workshops SHAPA offers its members free access to a major consultancy for legal and commercial advice, this can be accessed directly from the SHAPA website and includes over 700 publications which are free to download covering all aspects of running your businesses as well as a phone helpline. Digital marketing is vitally important these days, and is covered by what has now become by popular demand an annual seminar led by Susan Hallam MBE the renowned industry expert.

In March 2020 we will be holding our 12th consecutive digital marketing workshop, the things that have changed in the last 12 years in the world of digital marketing is to say the least revolutionary and SHAPA is proud to have a long standing partnership that informs and guides the membership to get the best out of their own digital platforms.

So, there is a great deal of activity within SHAPA to promote members’ interests. Many member companies work in partnership other member companies, so the regular easily accessible centrally located meetings act as networking opportunities as well as being attractive in their own right with quality speakers invited to update members on topical subjects.

We are sure that the following pages will serve to reinforce the value of beginning and ending your search with SHAPA for well informed, well established suppliers and installers of solids handling and processing equipment. Visit www.shapa.co.uk or email info@shapa.co.uk for further information and help.

SHAPA Newsletter | 57

Bella XN Mixer

How the Bella Fluidized Zone Mixer Works The Bella fluidized zone twin shaft paddle mixer by Dynamic Air achieves fast, high-capacity, low shear, precision mixing of either dry bulk solids or liquids with solids. Regardless of particle size, shape or density, materials are mixed with a fast, efficient, and gentle action with typical mixing times of 15 to 30 seconds.

A weightless zone created by low-speed counter rotating paddles generates very low friction without shear. This makes it ideal for abrasive products and fragile products that cannot tolerate rough handling.

Even flakes or spray-dried bodies remain intact.

The Bella mixer consists of twin drums which have two counter-rotating agitators with specifically angled paddles. They overlap at

counter-clockwise direction at the perimeter while simultaneously moving both left and right in the center (Figure 2).

Figure 1

the center and completely sweep the entire bottom of both mixer drums and allow it to be started under full load (Figure 1).

The material in the mixer moves in a horizontal

Figure 2

The material in Zone B (Figure 1) is in its normal gravimetric state as it is being moved and disbursed. In Zone A, a weightless zone is created which effectively lifts the ingredients to an almost weightless state allowing them to move freely and randomly, regardless of particle size and density. Thus the two zones’ interaction becomes highly efficient as every particle moves rapidly to a highly homogeneous mix, the key to the Bella Mixer mixing technology for fast, precise mixing.

The Bella mixer is available in stainless steel for food applications. Custom sizes, finishes and materials of construction are available upon request.

Read more here Dynamic Air Ltd. Milton Keynes, United Kingdom +44-1908-622344 E-mail: sales@dynamicair.co.uk www.dynamicair.com

DMN Westinghouse announces new appointment

Gericke sifters for mills and industrial bakeries

We are delighted to be able to announce that Paul Scott has joined DMN UK as the Sales Manager for the UK & Ireland.

For more than 70 years Gericke has been producing and selling a complete range of flour sifting machines for mills and industrial bakeries worldwide.

Paul has wide and impressive career experience on the system supply side of the processing industries. On leaving school, he joined Portasilo as an apprentice fabricator spending time on the shop floor and in the drawing office. This was followed by an in-house sales role and then Technical Services; a relatively new department at that time which enabled him to develop closer relationships with major customers.

After a short spell at Redler as a sales engineer, Paul returned to Portasilo to take up the position of Business Development Manager.

This involved foreign travel including India and the Middle East. Prior to joining DMN UK, 58 | SHAPA Newsletter

Paul was Area Sales Manager for Zeppelin.

On joining DMN, Paul said: “I am really looking forward to getting started and meeting customers. It’s a great challenge to develop those areas and industries where DMN sees new growth opportunities, while working with the team here to service our existing client base.”

Paul lives near York where any available leisure time is spent cycling. For more information on the range of DMNWESTINGHOUSE rotary and diverter valves please phone 01249 818401 or visit www. dmnwestinghouse.com

The purpose of these centrifugal sifters is to remove foreign bodies from the various flour qualities. This allows the flour quality to be kept constant and clean.

The success of these centrifugal screening machines in milling is mainly based on 3 points: 1. Very high screening capacity with mesh sizes from 400μm, and flow rates from 1 to 100t/h.

2. Compact devices in terms of throughput and simple design. This facilitates operation and maintenance.

3. An extremely robust construction ensures the longevity of the machines.

There are Gericke sifters being in operation for

Gericke centrifugal sifting machine

more than 40 years. This is sustainability.

These centrifugal screening machines have been further developed over the years to simplify cleaning and to meet new technical and regulatory requirements: Atex, CE/1935/2004 certification, easy screen change and disassembly for cleaning.

We would like to remind you that Gericke manufactures complete dosing, conveying and mixing systems for powders and bulk material.

In our pilot stations, all our equipment can be tested on an industrial scale.

For further information please do not hesitate to contact us: www. gerickegroup.com

Baghouse performance monitoring for reduced operating costs For optimum performance, fabric filter baghouses require correct and timely maintenance. ENVEA’s UK business (formerly PCME) manufacture a range of particulate monitoring systems, from simple leak to QAL1 certified measurement instruments providing Process Operators with an improved understanding of their baghouse operation.

Designed to monitor dust releases from single or multiple filter compartment baghouses, sensors installed in the clean gas output of each filter chamber are able to detect leaks as they develop, even down at very low emission concentrations. Knowing where leaks are developing enables process stoppages and maintenance times to be scheduled saving time and resources by

highlighting which bags require changing prior to potential emission limit excursions.

In addition, ENVEA now provide sensors to warn of hopper blockages, often a cause of bag filter abrasion and which can potentially result in explosions within the filter.

For Combustion applications which require sorbent injection such as lime or activated carbon, PicoFlow sensors are available to measure the quantity of injected sorbent. Ensuring the correct amount is injected maintains acidic conditions in the filter at the desired level preventing costly damage to the

baghouse and also helps to prevent sorbent over usage and consequent wastage.

Further details of ENVEA’s range of Particulate Emission and Solids Flow instrumentation can be found at www.enveauk.global For further information contact Linda Furnell, l.furnell@envea.global

LET’S TALK „… about your individual process solution and why AERZEN Engineering is the key to it.“ Matt Kilgarriff, Special Products Manager

+44 0208 502 8122

matt.kilgarriff@aerzen.co.uk

When it comes to your best solution, you should be as uncompromising as we are: It must be precisely tailored to your requirements, absolutely reliable and highly efficient. With individual assembly configurations and customised services, AERZEN has been serving demanding process applications worldwide for over 150 years. Thanks to efficient compressors and blowers, comprehensive engineering knowledge and pronounced consulting competence, AERZEN can implement your individual customer requirements exactly. The unique AERZEN product expertise ensures you an efficient process solution and sustainable plant availability. www.aerzen.co.uk LT_Processgas_210x148_UK.indd 3

02.01.2019 08:05:07

SHAPA Newsletter | 59

James Miller, Director at Dustcontrol UK

How the food industry can save time, money and resources on cleaning Dust is a major issue in the food industry thanks to the presence of airborne allergens, which, while a problem for workers’ long-term health, can also pose issues further down the line for consumers.

food industry to ensure the protection of workforces and the quality of products, while adhering to the relevant health and safety regulations.

The food industry has special requirements and control of components and equipment used in production is extreme, with a special focus on migratory risk, surface finish and antistatic properties.

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Failing to undertake appropriate cleaning measures and tackling dust in hard to reach areas can affect product quality, while also running the risk of cross contamination – with potentially fatal consequences in the event of an extreme allergic reaction.

cotton and pollens can cause inflammation of the airways, which can develop into infections such as bronchitis.

For the workers themselves, exposure to fine dusts from flour,

It is therefore essential that efficient measures are put in place within the

Overexposure to hazardous dust for a prolonged period of time can also cause permanent disabilities, and even death.

As a deeper understanding of the harmful properties of dust are better understood, businesses are taking steps to control and confine areas in the workplace where excessive dust is created, but the necessary cleaning required often takes a considerable amount of time, money and resources.

Research we carried out found that a third of UK food businesses spent between 11 and 20 per cent of their annual turnover on cleaning, with a further one in six claiming to spend even more than that.

On top of unnecessary costs, we also discovered one in four food companies spent more than 21 hours a week cleaning, while a third assess their cleaning processes at least once a week, on top of the time they spend actually cleaning.

It’s a snowball effect - not having the equipment to effectively capture dust at its source, both where and when it’s created, leads to an accumulation of dust, which in turn will naturally increase the time and money spent to combat it.

Streamlining cleaning processes and using the optimum equipment for each scenario plays a large part in reducing time consumption, as well as unnecessary costs. Source extraction systems are one of the most effective ways of achieving safe and hygienic food production, as they are designed to ensure food processing areas are the cleanest they can be – keeping the potentially

serious side effects of dust to a minimum.

With hygiene requirements within the food industry being extremely stringent, a complete source extraction system can be fully integrated into the production process for recycling or used as a centralised vacuum cleaning system.

By combining safe food contact, autoclavable, colour-coded, detectable, antistatic and FDA compliant properties to fully integrate a comprehensive system, food processing companies can yield higher quality products, whilst making savings on factorywide cleaning costs.

food industry, courtesy of strict process and control.

With companies spending considerable amounts of time and money on cleaning, it pays to make sure they’re doing it right.

Streamlining cleaning processes and using the optimum equipment ensures businesses are utilising resources and saving valuable time and costs on creating a safer working environment.

Overall, cleaning is a serious business in the SHAPA Newsletter | 61

Heavy Duty Butterfly Valve Posi-flate 585/586 butterfly valves feature seats and discs for application pressures up to 10 bar.

The design improves on existing 485/486 seats to provide the same incredible valve life at even higher pressures. The 585/586 valves are designed to fit PN 10 flanges, and come in sizes 80mm to 600 mm.”

The Posi-flate Series 585/586 butterfly valves are designed for the most the most severe of applications. They are ideally suited for very abrasive materials which can reduce valve life. The inflatable seat design provides a better seal by utilizing air pressure to expand the seat against the disc, providing more sealing area and an even pressure distribution against the disc every time. The seat automatically compensates for wear when it inflates against the disc, extending valve life considerably.

Because the Posi-flate disc only makes casual contact with the seat during opening and closing, torque requirements are substantially lower. This ease of movement also allows the disc to come to a perfect 90-degree position every time.

Additionally, the smooth profile of the disc helps material flow easier and reduces build-up. For unique fail-safe monitoring, a pressure switch can be utilized to verify a perfect seal.

The Posi-flate 585/586 butterfly valves are available in a wide variety of construction materials including stainless steel and lightweight aluminum.

Read more here Posi-flate Milton Keynes, United Kingdom + 44 1908 622366 E-mail: sales@posiflate.co.uk www.posiflate.com

Dust Control for Processes; one day short course for industry An examination of the different methods for dust minimisation, capture and extraction.

Fine particle content can lead to flow or dust emission problems The capture of airborne particles is a requirement that can span a wide range of industries. At a low concentration the fugitive material can take the form of airborne dust whilst at the other extreme the separation of particles from the air occurs with much higher concentrations (i.e. reception vessels for pneumatic conveying

62 | SHAPA Newsletter

systems or systems vents).

For either type of application good disentrainment efficiency is of paramount importance.

Aspects of control of fugitive particles or capture There are four potential sequential approaches that can be employed. These are: • Prevention during handling • Containment • Suppression • Extraction and Collection Learn more about these strategies and technologies at the Wolfson Centre for Bulk Solids Handling Technology.

Contact Caroline on +44 (0) 20 8331 8646 wolfson-enquiries@gre. ac.uk or book on line

Posi-flate butterfly valve

Consultancy and Short courses for the Process Industry: Bulk solids handling technology

We support industries that are seeking to resolve process problems, develop design schemes for plant expansion, or simply improve product quality.

Consultancy services

Some of our Consultancy services include advising on: Storage and Discharge of bulk materials Pneumatic Conveying of bulk solids Spoiling of materials in storage and in transit Plant and Equipment design/redesign Ship Unloading/ quayside operations Control of plant wear Dust control Bulk Materials characterisation ATEX/DSEAR compliance Expert Witness services

• • • • • • • • • •

Short courses for Industry

We also provide a range of short courses to help delegates identify potential bulk materials handling problems and advise on how to avoid and/or overcome these issues.They fall under 4 main categories Pneumatic conveying:

storage of bulk materials:

•Pneumatic Conveying of Bulk Materials • Pneumatic Conveying System Design • Rotary Valves; Design, Selection and Operational Issues • Commissioning and Troubleshooting ‘Hand’s On’ Pneumatic Conveying Systems

general bulk materials handling:

• Storage and Discharge of Powders and Bulk Solids • Design of Equipment for Storing and Handling Bulk Materials • Biomass Handling, Feeding and Storage (can be adapted to

other materials such as waste, recycled goods, pellets)

sPecialist areas of concern:

•Overview of Particulate Handling Technology • Dust Explosions - How to demonstrate DSEAR/ATEX Compliance • Port and Terminal Operations for Bulk Cargoes Measurement of the Properties and Bulk Behaviour of Particulate Materials • Introduction to Processing Dry Solid Materials

• Caking and Lump Formation in Powders and Bulk Solids • Undesired De-blending and Separation in Processes and Equipment • Electrostatics in Powder Handling • Numerical Modelling of Solids Handling and Processing • Dust Control in Processes Powder Handling and Flow for Additive Manufacturing

bulksolids.com

Lyn Bates, BMHB.

The need for a

‘USER GROUP’

of Companies handling loose solids.

The economic benefits offered by continuous processing over batch is driving the pharmaceutical industry to follow the route of food, chemical and mineral industries in adopting this method of production, (1).The historical mindset of management to employ batch processing is reinforced by the need to change in design methodology from a unit operation to a systems approach and recognise the consequent importance of the physical properties of the bulk material to the handling of the product.

Research and design importance are rightly directed to the constituents and process of production of a suitable product, but it is separately important that the production method is reliable and does not adversely effect the quality of the output. (2). This was dramatically illustrated in other Rand reports that highlighted the wide relative inefficiencies of plants handling solids and those handling liquids and gasses. (3).

This discrepancy was attributed to the lack of data relating to relationship between the physical properties of the components and their handling characteristics.

Unresolvable segregation issues were also reported as responsible for the failure of a $300,000 pharmaceutical project.

The need for a wider understanding of the handling characteristics of bulk solids is not confined to the pharmaceutical industry, but is virtually universal, (4). However, whereas there are at least three trade organisations of manufacturers of solids handling equipment in UK alone, (5), there is no organisation that represent the vast number of manufactures that use bulk solids within their production facilities or co-ordinates research in the subject, either at universities or on behalf of industries with common interests.

The paucity of teaching powder technology in the syllabus of many universities does not currently favour a significant change in the level of support available to design improvements. It is noticeable that, apart from Andrew Jenike’s contribution to hopper design, most advances in equipment design has originated from equipment manufacturers than university research.

The UK Government has currently many others priorities and an early effort in 1959, (6), as part of Harold Wilson’s “White heat of technologies” splurge. Despite sterling work in bulk technology, the laboratories were sold off to form a car park in a Heseltine economy purge. Government will not give attention to this, so it is up to a major manufacturer to take the lead and support The British Materials Handling Board in the formation of a ‘Bulk Users Association’, which was set up by the Government for these objectives.

Refs.

1. ‘Modernizing Pharmaceutical Manufacturing: from Batch to Continuous ’Production’, Journal of Pharmaceutical InnovationSept.

2015, Volume 10, Issue 3, pp 191–199|..

2. ‘ Linking R & D to problems experience in solids processing’. Merrows. E. Rand Report 1984.

3. ‘Understanding Cost Growth and Performance Shortfalls in pioner process plants’, Rand Report. Merrows.E. 1981.

4. ‘The Global status of Bulk Materials Handling’. BMHB 5. SHAPA, MHEA, PPMA 6. Warren Spring Laboratories, 1959 – 1994.

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PROTECT YOUR DUST FILTER AGAINST FIRE AND EXPLOSION

Firefly’s unique Spark Detection System is based on true IR spark detectors that are insensitive to daylight.

They are designed to detect all dangerous ignition sources, such as hot dark particles, sparks and flames within milliseconds.

More information at: www.orthos.co.uk Call us: 01858 464246 For enquiries: sales@orthos.co.uk

SHAPA Newsletter | 65

Lyn Bate of Ajax Equipment

Cost effective benefits of cooling screw design Screw feeders and conveyors are widely used for the handling of bulk materials in situations where it is beneficial for the product to be subjected to heating or cooling, in some cases this being the prime function of the equipment.

A feature of this form of material transport is that there are a range of independent design options that influence to efficiency of heat transfer that are disproportionately in the cost of manufacture. A degree of heat transfer can be secured very economically, but fabrication cost increases according to the form of change, so an optimum cost/ effective solution requires a degree of design expertise.

The choice of ‘U’ trough or circular casing depends on various factors, such as access for cleaning, containment and heat transfer efficiency.

Similarly, the selection of heat transfer media independently rests on factors such as the availability of resources, thermal task and range of temperature change. Options include: ambient or chilled water, oil, hot or direct fired gas or electric.

However, the thermal benefit

and cost of design differences in the machine construction increases in the following generate manner, although not in similar proportions.

- Fit rotatory glands on the screw shafts for heating or cooling media.

- Continuous heavy weld both sides of the screw flights.

- Fit thicker flights - Fit shorter pitch flights - Use larger centre tube.

- Fit jacket to casing.

- Minimise flight tip clearance by matching casing to screw deflection.

- Select oversize screw running slower.

The use of screws to extract material from the outlet slots of heat transfer hoppers enables extra cooling by adapting the screw for heat transfer by one or more of the modifications listed. In these circumstances there is an important additional design criterion as the overall heat transfer efficiency of the system is radically influenced by the uniformity of the discharge velocity profile along the outlet slot.

An uneven rate of discharge from different regions of

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11186 PPMA Directory_273x90

the hopper results in a variation in residence time. Overall heat transfer is less efficient than when the outflow is uniform, but unfortunately uniform extraction to produce an even flow rate is rarely achieved. (1).

It is well appreciated that a screw with flights of a constant pitch will preferentially extract product from the first section of the hopper to which the screw is exposed. However, a common misconception is that screws which vary in pitch will give a reasonably even feed, whereas the variation in feed rate is usually massive. (Fig 1.). This assumption probably arises from the false concept that the axial transfer capacity of the screw is fixed by the swept volume of rotating, whilst it actually varies as the geometry and surface friction of the product in the inclination of the flight, which changes from where it is adjacent to the centre shaft up to the flight outside diameter. (2).

The variable flight helix affects the efficiency of axial transfer capacity, as does the frictional drag of the centre tube, so a ‘mean effective helix angle’ of flight must be assessed for extraction calculations. A basic impediment to uniform extraction is that the

initial ‘draw’ extracted from the hopper by the first flight will extract and axially transfer its full capacity, but subsequent sections of the screw can only transfer their differential increase in transfer capacity. This impediment to even extraction is addressed by a feature of feeder design, as Ajax reg.

Design No. 6038827.

Some design expertise is then required to exploit the relative merits of design change of flight pitch, shaft size, flight thickness and the face friction. Changes in screw construction are theoretically required for every flight, but this number may be more than halved and change doubled in effectiveness by fitting right and lefthand flights to a central outlet.

The extra reduction of over 50% of the effective outlet length follows from the requirement for a central insert to prevent direct leakage of the hopper contents. This insert must stimulate mass flow and the final two exposed flights prior to the inlet has.to extract material from directly above and half that resting above the insert. The dynamic shear strength of the flowing media can be exploited to some extent, especially with short pitch flight sections, to mitigate minor theoretical velocity differentials.

References 1. Bates.L. “Capturing the elusive benefits of uniform extraction rom hoppers” Proc. Ind.Infom. Dec. 2019.

2. Bates.L. “Entrainment pattern of Screw Feeders”. J. Eng. Ind. May 1969, 91(2): 295-302

POWDERS

GRANULES

3/8/11

PASTES

BATCH

11:41 am

Page 1

CONTINUOUS

The

optimum solution for Mixing

from

John R Boone

Versatile Mixing Machines, the Complete Range from 2 to 25,000 litres Helical Blade (ribbon): Sugar Paste to Herbs Delta Blade (plough): Cookie Mix to Flavours Rotary Drum: Tea to Muesli Paddle Blade: Viscous Pastes Coaters: Herbs, Spices, Flavourings Batch machines or Continuous Complete mixing plant design to commissioning Test mixers available for production development Production scale machines for short or long term hire Get more from your existing plant Existing Mixers and Systems can be refurbished and upgraded Contact our applications engineer for an assessment T: +44 (0)1260 272894 www.jrboone.com e: sales@jrboone.com J.R.BOONE Ltd., 18 Silk Street, Congleton, Cheshire, CW12 4DH, England

MIXING SOLUTIONS WORLDWIDE

SHAPA Newsletter | 67

Fit for Liquids Under the banner “Fit for Liquids“ UWT is proud to launch a brand new product series in the field of liquids measurement. The new capacitance measuring sensors for continuous and point level detection offers new options for the UK and international market.

With the new UWT liquid level detection range, pin-point accuracy and total reliability, UWT offers continuous and point level detection in liquids, pastes, foam and slurry as well as interface measurement.

The UWT sensors work with the combination of the capacitive measuring principal and the change in frequency of the sensor which has a far greater switching accuracy than just the capacitance when the probes are submersed in liquid. This allows the probe to also maintain its high accuracy when it comes to viscous media like syrup or honey as the sticky build up on the probe does not affect the switching output signal. This ensures the best possible dry run detection of any system.

Another further advantage is the ability to measure interface between liquids – water and oil, foam and beer – with high repeatability and accuracy. All devices are equipped with potted electronics and work with the unique “Inverse Frequency Shift” technology. They provide a robust, certified construction and offer suitable solutions for a wide variety of liquids, pastes and foams – whether to be used for aggressive chemical applications, within the demanding food industry or in wastewater handling. Through a variety of metal rope, cable, rod and pipe extensions the units can be easily adjusted to single conditions of the process vessel.

Thanks to the integrated “Tip Sensitivity” technology the Capanivo® range with the CN 7 and CN 8 level detectors guarantees high reliability for products that cause caking. The Capanivo 7000 delivers a very compact design for limited space, available as enclosure or integral cable version as well as synthetic model.

The Capanivo® 8000 on the other hand is a universally applicable all-round talent due to its range of process connections, hygienic versions and the high safety standard.

UWT has expanded the RF limit switch line with the robust Rfnivo® 8000 that includes a hightemperature version for a wide temperature range from -40°C to +400°C and pressure resistance up to 35bar. The PFA isolation ensures high degree of chemical resistance.

The NivoCapa® 8000 measures the continuous level in conductive and non-conductive materials with complete accuracy. At the same time the LCD display with control buttons and diagnostic function make the level sensor very userfriendly. The integrated “Active Shield“ technology found in the RF and NC devices ensures precise measuring results even when detecting media that tend to stick to the probe.

For further information contact UWT on: 01743 718883

sales@uwtuk.com www.uwtuk.com

68 | SHAPA Newsletter

HSE Requested Information Regarding LEV SHAPA along with the HSE and others are part of the Industry and Regulatory Forum on LEV, we are collectively working together to promote a safe environment in the workplace.

In order for the HSE to better understand the current state of LEV in the workplace they are gathering information to support a project into the ‘Investigation of Critical Factors for the Safe Use of Recirculating Local Exhaust Ventilation’.

Can you please help in this process by providing answers based on your experience to the following questions (you can download these questions here)

1. What types of filters are commonly used in industry sectors for LEV systems? · Bag; or · Cartridge 2. What filter media and/or filter standard and class (e.g.

EN 779 F9, ISO 16890 ePM1 80%, EN1822 H13, etc.) are commonly used in: · Main or primary filter? · Secondary filter (if any)?

3. Should filter media be specified for particle form, size and chemical composition?

4. Should LEV filters be required to be tested against a standard and meet a defined filter class?

5. What marking should be required for filters?

6. Should all recirculating welding fume devices be type tested against the welding equipment standard (EN15012-1)?

7. What criteria should be used to decide when type M and H vacuums are used for on tool extraction?

8. Are the device and filter standards fit for purpose for LEV systems?

Could you please forward your answers directly to Robert Ellis who is leading the initiative from the HSE robert.ellis@hse.gov.uk

Capanivo ® Compact & flexible

Clever capacitance level detection of liquids, pastes, foam & interface measurement Use in non-metallic containers possible!

CN 7000 The pocket-sized one Compact design Enclosure version or integral cable version Synthetic version available Chemical resistance Optional PVDF probe SensGuard protective sleeve 2-wire instrument ” tivity ensi y S p i g “T nolo Tech

CN 8000 The allrounder Pipe and cable extension Range of process connections High safety standard Hygiene versions Very high sensitivity Digital version with LCD

(Download the questions here)

UWT (UK) Ltd • 01743 718883 •

sales@uwtuk.com www.uwtuk.com SHAPA Newsletter | 69

Vibratory Sieving Dust

Containment and Control Sieving and screening powdered products greatly contributes to dust generation, not only when product is poured or dumped on to the sieve screen, but when the sieve applies high powered vibration to the mesh screen. the sieve, minimising impact on the operator and generation of airborne dust from dispensing the product. A dust-tight seal to the sieve is maintained thanks to the metal detectable silicone diaphragm seal. The hood is available with a pneumatically assisted door that can be closed when the sieve is in use to supress dust as powdered product falls into the vibrating sieve below. This helps keep the dust contained and prevents it from entering the surrounding atmosphere, protecting the operator, preventing loss of product and mitigating the risk of contaminates entering the sack tip station when not in use.

Farleygreene are all too aware that dust control has become an ever-increasing concern for manufacturers in a variety of industries where product processed in bulk can produce a large amount of dust. Regulatory standards are also becoming increasingly tight as inhalation of airborne dust particles are contributing to poor health of operators.

Heavier dust particles that settle on equipment also add to the risk of fire and explosion, as well as contributing to unnecessary maintenance and a shorter lifetime for costly equipment.

DUST CONTAINMENT Farleygreene have developed a range of different solutions that 70 | SHAPA Newsletter

help control dust when sieving and screening. Their Sievmaster range offers a variety of different sieves designed to handle various requirements within manufacturing. The most popular product for plant operators is their Slimline sieve, available in four different diameters depending on the throughput requirement. The two smallest Slimline sieves are also sold with a sack tip option, as the ‘Sievmaster Easilift’, designed for processing powders in bulk from sacks or containers. Providing a sack rest table and hooded enclosure, sacks up to 50kg can easily be cut and emptied into the sieving compartment. When in use, the sack tip hood remains vibrationally isolated from

DUST EXTRACTION The standard dust hood is fitted with a Ă˜150mm dust extraction port, ready for connection to an external extraction system to draw air-borne product into the hood and away from the operator during sack tipping. Alternatively, local dust extraction units can be built directly into the dust hood itself. These are available in two varieties; either with an electric fan or a pneumatically powered vacuum pump. Both draw air through a set of filters and feature reverse jet purge cleaning.

This means that when the dust hood door is closed, a powerful pulse of air is sent back through the filters, blowing any trapped product off them to fall down to the sieve, minimising loss of product.

concerns as equipment can be more difficult to keep clean. Therefore, a significant advantage of a combined sieve and sack tip station is that transfer between separate machines is eliminated, reducing the risk of contamination or product leakage.

EXPLOSIVE RISKS In order to prevent any explosive risks from powder generated during processing, Farleygreene Sieving equipment conforms to the latest ATEX requirements and can be certified for Zones 20, 21 and 22, depending on options.

Several Earthing options are also available including, 430 Chrome steel earth clips and food-grade conductive mesh ring gaskets. However, one of the more popular options is the direct mesh earthing bar which screws directly into the mesh ring through a slot in the body of the sieve. This offers a way of ensuring the mesh is properly earthed without having to open the sieve.

HYGIENE CONCERNS Particularly for the food industry, the generation of excessive dust can also contribute to hygiene

Earlier this year, Farleygreene released a new product to their sack tip range, the Easilift Ultra, designed specifically for the hygiene conscious food industries. The hood on the Ultra version is rounded with fewer crevices, improving product flow and cleanability. The externally mounted sack tipping table mitigates the risk of contamination of the product from the outer surface of the sacks or containers, and folds away when not in use to minimise surface areas prone to dust collection. The door has also been designed without welding to reduce deformation and provide a flatter sealing surface, ideal for dust suppression. It is also worth noting that this more hygienic style hood is also available with the pneumatically assisted door and integrated dust extraction system.

Nearly all materials handled in bulk generate dust, but these containment and control solutions offered by Farleygreene can help manufacturers take preventative action to keep operators safe.

Farleygreene have been designing and manufacturing sieving equipment at their UK factory since 1976, supplying machinery to some of the world’s largest manufacturing companies.

To learn more visit farleygreene.com, email info@farleygreene.com or call +44 (0) 1256 474 547.

SHAPA Newsletter | 71

INVESTMENT CASTING SAND

AND FLOUR CONVEYED FROM BULK BAGS AUTOMATICALLY, DUST-FREE O’Fallon Casting is a major manufacturer of thin-walled, nonferrous investment castings.

The company’s commitment to automation has helped it grow. Examples include installing robots to move the patterns through its slurry and sanding steps, and converting from manual bag dumping to automated discharging from bulk bags using Flexicon bulk bag dischargers and flexible screw conveyors.

Bulk-Out® model BFC bulk bag dischargers unload three varieties of sand which flexible screw conveyors transport to the drum sanders. A cantilevered hoist and trolley lift each bag into the discharger frame.

72 | SHAPA Newsletter

Converting from manual dumping to automated discharging The investment casting process can be labour-intensive. It begins with a wax pattern, which is identical in shape to the final casting. This pattern is dipped into a slurry, which partially drains away. Next, the slurry-coated pattern passes through rotating vessels, called drum sanders, each of which coats the pattern in a different type of sand. After the slurry hardens, the wax is melted away and replaced with a molten metal to make the casting.

As the wax patterns move through the slurry and sanding steps, they consume the fine powder used to make the slurry—called flour—and three varieties of sand. For years, operators had replenished the slurry vessel and drum sanders by hand, carrying and emptying 23 kg bags into them. In 2007, O’Fallon began buying the materials in 1,360 kg bulk bags and adding them automatically by machine.

For this, the company chose equipment from Flexicon,

which supplied four BFC bulk bag dischargers and a combination of single-run and interconnected flexible screw conveyors. One dischargerconveyor system is devoted to delivering flour to the process, while the other three deliver sand to four drum sanders.

Systems promote bulk bag evacuation, contain dust Bulk bags are delivered to each discharger by forklift and then loaded into the frame using a hoist and trolley that travels on a cantilevered I-beam. Next, a SPOUTLOCK™ clamp ring atop a TELE-TUBE™ telescoping tube is raised pneumatically and secured to the bag spout.

This serves to both contain airborne dust and maintain continual downward tension on the bag as it empties and elongates, promoting discharge from the bag.

While each sand variety flows freely from the bulk bags and hopper, the flour tends to bridge, according to Matt Cavins, metallurgical engineer. As a result, the flour discharger includes

Once the bag spout is secured by the Spout-Lock™ clamp ring, the Tele-Tube™ telescoping tube applies constant downward tension as the bag empties and elongates to promote complete discharge and contain dust.

Flexible screw conveyors moving sand to each drum sander terminate at a discharge adapter and downspouting.

In delivering ‘flour’ to the process, a lifting frame, cantilevered I-beam, trolley and hoist place the bag in the discharger frame.

Flow-Flexer™ bag activators (top corners, lower half of frame) promote flow as the flour tends to bridge.

two additional mechanisms to promote flow: FLOWFLEXER™ bag activators which raise and lower opposite bottom edges of the bag into a V shape, and a vibrator mounted on the hopper wall.

“Those features were major considerations for us,” Mr. Cavins explains. “We wanted to make sure that it was discharging from the bulk bag smoothly and that there wasn’t a lot of dust created where the hoppers are.”

One of the benefits of receiving the sand and flour in larger bulk containers is efficiency for O’Fallon’s operation as it enables supplying the powders to multiple locations from a common bulk materials location.

To achieve this, flexible screw conveyors automatically transport the materials through openings in the walls to the slurry vessel and drum sanders.

Since the design of the flexible screw conveyors is well suited to complex equipment layouts, the series of conveyors allows the Flexicon bulk material handling system to feed the powders to varied locations. In O’Fallon’s layout, powder use points are anywhere from 2.1 m

One of three varieties of sand on its way to the drum sanders.

to 13 m away from the bulk bag dischargers.

Further enhancing efficiency, the material conveyance is automated. These additions are weight-based, with a scale beneath each vessel signaling a PLC when to start and stop the conveyors.

Automation cuts downtime, manual effort O’Fallon uses about two bulk bags of flour per day, and each of the sand lines consumes about two bulk bags per week. The materials are heavy and abrasive, and the conveyors handle them well, Cavins says.

“We really haven’t had many issues. It’s been almost 10 years in operation now, at least on the sanders, and we’ve replaced maybe one drive, and that’s on three systems with multiple drives. Two conveyor tubes have been replaced in that 10-year span, he said. The polymer tube on the flour conveyor is more prone to wear than the steel tubes on the sand conveyors...but it’s really not enough to switch to a steel tube,” Mr. Cavins says.

Robot dips wax patterns in the slurry vessel before sanding. O’Fallon is a leader in thin-walled nonferrous investment castings.

“We have more uptime and a safer working environment.”

Flexicon (Europe) Ltd Whitstable Kent CT5 3RB +44 1227 374710 sales@flexicon.co.uk www.flexicon.com O’Fallon Casting +1 636-272-6176 www.ofalloncasting.com

SHAPA Newsletter | 73

Jim Lenihan, President of Gemco Valve Company

Valve Options Powder/Solids processing valves present more performance challenges than gas or liquid valves and therefore often require more consideration of available options and customisation. Before we detail the two most common options, readers may find it useful to review the basic factors to consider when specifying solids processing valves in our article Valves for Powders.

High Temperature Options Soft seated valves with elastomers are typically limited to around 200C. Valves are considered high temperature when they are exposed to temperatures above this for extended periods. Some elastomers may handle momentary exposure to higher temperatures but this is generally not well defined and systems should be designed for worst case process conditions.

This is different from upset

conditions where after an out of normal limits event, the process is shut down and the equipment is inspected and maintained before restarting operations.

For temperatures between 200C to 330C, FFKM (Perfluoroelastomer) O-rings such as KalrezÂŽ 7075*1 may be used for valve body and valve stem seals. However, metal seats are recommended since soft seats will degrade and erode quickly and will not

provide a reliable shut-off. Metal seated valves have a tendency to jam as the valve heats and expands and are often set with a predefined clearance between the seat and shutoff disc at ambient temperature.

Of course this affects shut-off class and is not acceptable in some applications. Spring loaded seats that allow for thermal expansion are an option in smaller sizes.

Carbon/Graphite based flange gaskets such as Flexicarb*2 are common in these applications.

These gaskets are typically not reusable. Graphite stem packing such as GarlockŽ 1306*3 is typical for high temperature and some can go to 455C/850F in atmosphere and 650C/1200F in steam. Inconel wire reinforcing in expanded– graphite yarn is an additional option that provides more rigidity and dependability to the packing.

Extreme Temperatures For bubble tight shut-off at extreme temperatures above 450C, static seals may be the best option. These can vary from standard ANSI or DIN flanges with gaskets and fasteners to Spider Clamps that allow for quicker mounting and removal. Cleanliness is critical to this process so seal faces and gasket surfaces need to be inspected and any contamination removed on every use.

74 | SHAPA Newsletter

NASA’s ISRU (In Situ Resource Utilisation) Technology Development Project for hydrogen reduction of regolith. The valves were used in ROxygen field tests on Mauna Kea, HI in 2008.

High Temperature Actuators.

While some actuators are available with high temperature O-rings/seals, the preferred method is to isolate the actuator from the process temperature. This can be achieved by insulating the valve and process piping and/ or providing a heat shield plate mounted between the actuator and valve. Another option is to provide a drive stem extension and add radiation fins to the housing extension to dissipate the heat.

Flush Mount Options Most discharge valves for vessels and processors leave a dead space where the valve mounts to the vessel. Dead space is defined as the volume between the valve shut-off element and the inside wall of the vessel. This can be an issue for mixing and processing applications where the product in the dead space remains unmixed or unprocessed.

For smaller valves - up to approximately 80mm - a mounting pad on the vessel allows the shut-off disc or ball to be close enough to the vessel to minimise the dead space to an acceptable level for most processes. This often requires the actuation package to be mounted at an angle to avoid interference with the outside wall of the vessel. Most ball valve manufacturers offer this option. For segmented ball/ spherical disc valves, angled stems are not available.

Instead, an extended stem and valve mounting bracket can place the actuator outside the interference area.

As the discharge valve increases in size from 100 to 300 mm the solution is more challenging depending on the amount of dead space that is acceptable to the process.

To minimise the dead space, a mounting neck piece or pad is welded into the vessel wall and bring the diameter of the ball segment/spherical disc flush with the inside of the vessel.

However, to eliminate dead space, the ball segment and seat need to match the form of the inside of the vessel which can be flat, radius or conical.

This customisation requires 3D modeling and manufacturing with CNC equipment. The geometry of the ball segment means that the shut-off disc will penetrate into the vessel as it opens and closes. If the processer has paddles, vanes, ribbons or other moving parts then interference with the ball segment needs to be avoided. The can be achieved by interlocking the controls so the valve will not operate in the interference condition. This design and build to order comes with added costs and is only justified in exceptional applications.

Shown is a model of a retrofit, flush mount, valve design for a major producer of food ingredients who wanted to improve the mixing quality of an existing blender.

The project involved removing an existing butterfly valve and discharge cone and replacing it with a spherical disc valve and weld neck. The seat and spherical shut-off disc were manufactured to match the inside radius of the blender and eliminated the dead space.

*Gemco Valve Company mentions these brand names as examples only and receives no consideration from the owners. There are many completive products available. *1 Kalrez® is a DuPont brand and is available in a wide range of grades. *2 Flexitallic Industrial gaskets supplies a range of high temperature gaskets. They do state “Flexicarb will oxidise over time. Care should be taken when considering the use of Flexicarb foil for applications above 650°F (343C).” *3 Garlock® packing is available in a range of materials and grades.

SHAPA Newsletter | 75

Boone Mixers

are at the centre of BASF’s New Rodenticides Line Boone Mixers have supplied two Horizontal Helical Blade Mixers (HHBM) to BASF in Widnes for their new production line, manufacturing rodenticides with a marzipan-like texture to meet the growing demand world-wide for alternatives to warfarin as rodents develop resistance and traditional rodenticides become less effective.

BASF have developed a rodenticide that combats the increasing problem of evolving drug resistance, while being very palatable to encourage the animals to consume the bait.

As customers world-wide take up the new product, BASF needed a new production line and following extensive tests the new Boone HHBM mixers were selected as a key part of that development.

The base of the product is a simple mix of fat, sugar and flour, mixed

in the Boone HHBM mixer with the ‘active’ components. The mixed product is a crumb mix that is then formed into small blocks and packed for use.

Although the end products may be very different, in some ways the challenge of mixing the product is very similar to any other crumb, even crumble dessert topping. It has to be thoroughly and homogenously mixed, including micro-ingredients, while not over-working the mixture, which would compact it and make it difficult to form. Boone HHBM accomplishes this using a low mixer speed and omega shaped mixer shell with a unique, high efficiency interrupted spiral mixer blade configuration. This has a low surface area mixer blade that reduces energy input to the mix and is easy to clean. The omega shaped mixer

shell is ‘short and tall’, so end-to-end mixing is optimised, and the mix fully discharges through a knife gate for packaging.

Boone also designed and supplied the liquid oil spray feed system to match BASF’s specification which together with a heating and cooling jacket to control mix temperature and extend the range of products that can be made in the HHBM. Because of the ingredients used, the mixer, inlets and outlet are designed for ATEX internal/ external Zone 20/22. The Boone Standard ATEX Mixers and ancillary equipment are designed to meet that standard.

According to Benjamin Charnock, Facilities manager at BASF, ‘Production is ramping up, and we need to respond to the demand. The Boone mixer is helping us to do that, and we are planning to build and add another line in the very near future.’

(HHBM are also known as Ribbon Mixers)

JR Boone Ltd 18 Silk St, Congleton, Cheshire CW12 4DH, United Kingdom Tel: +44 (0)1260 272894 e-mail:sales@jrboone.com www.jrboone.com

76 | SHAPA Newsletter

GROUND-BREAKING NEW PRODUCT FROM

SEMI AUTOMATIC EASY CLEAN 12000 GAUSS ROTARY MAGNET WITH ATEX 20 APPROVAL Greenwood Magnetics are proud to launch a ground-breaking new rotary magnet approved for use in ATEX Zone 20 internal environments.

The 12000 Gauss Semi-Automatic Easy Clean Rotary magnet ATEX 20 is approved by notified body Intertek:

and construction of products intended for use in potentially explosive atmospheres given in Annex II of the Directive”

“Intertek Testing and Certification Limited, Notified Body number 0359 in accordance with Article 17 of Directive 2014/34/EU of the European Parliament and of the Council dated 26 February 2014, certifies that the product has been found to comply with the Essential Health and Safety Requirements relating to the design

The design is protected by registered design number 007214622 Real-world performance The Greenwood Easy-Clean Rotary Magnet is an inline magnetic separator used in vertical process lines for the extraction of ferrous and paramagnetic particles from dry product.

It has been designed specifically for products susceptible to bridging such as milk powder or starch. The centrally mounted grid gently rotates extracting fine ferrous and semi– ferrous particles whilst ensuring that the product remains free flowing, avoiding bridging or clogging.

Class-leading safety The risk of explosion when handling and processing fine powders is well known. We believe the new Greenwood Rotary Magnet is the first to combine 12000 gauss magnet strength with easy-clean technology in a unit that is approved for use in ATEX 20 environments where dust/powder explosion risk is highest.

Class-leading magnet strength The new rotary magnet also offers class leading strength.

Many suppliers of industrial magnet systems quote the internal gauss of magnets in their products. This is the maximum available magnetic strength of the SHAPA Newsletter | 77

magnets inside the magnetic tubes. However, this means the actual strength is reduced on the contact surface.

The new rotary magnet from Greenwood uses a ‘scraper-plate’ design which means that the easy clean magnetic tubes have a magnetic strength of 12000 Gauss- tested and certified on THE CONTACT SURFACE. Greenwood Easy-Clean technology Greenwood Easy-Clean system allows the magnets to be readily extracted from the rotary unit so the ferrous and paramagnetic particles fall into a collection tray for easy removal and analysis. This delivers a better, faster method of cleaning, improving operator safety and efficiency.

ATEX 20:ISO9001 Integration Intertek has also audited Greenwood Magnetics ISO

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9001quality management system and confirmed it integrates fully with ATEX under Annex 1V in accordance with article 17 of the Directive 2014/34/EU. Real-world success Greenwoods have already received their first order, even before the official launch of the product.

For more information about our new ATEX-certified rotary magnet, other bespoke magnets, manufactured to requirements or if you would like us to test and certify your existing magnets, please do not hesitate to contact us: Greenwood Magnetics Tel: 01706 645824 Email: sales@greenwoodmagnetics.com Web: www.greenwoodmagnetics.com

Christian Dunne, Global Head of Sterile Solutions at ChargePoint Technology

How new technologies are influencing

advanced aseptic

are becoming more stringent, with increased emphasis on using the best available technologies and performing comprehensive, sciencebased risk evaluations of procedures. The industry is seeing significant developments in technology in response to the hazards involved in aseptic processes, as product sterility must be ensured and contamination prevented to avoid potential consequences to patient safety.

Introduction Recent years have seen significant improvements and innovations in technologies used in aseptic processing. With the rise in demand for small batch, novel therapies, manufacturers are looking to develop more vigorous and flexible containment strategies using new and innovative solutions.

The regulatory requirements around sterile manufacturing

Current market landscape Containment technology experts are continuing to innovate to meet the evolving requirements of the sterile product manufacturing sector.

This is one of the factors driving growth in the global advanced aseptic processing equipment market, which is set to reach a CAGR of 3.8% between 2017 and 2024 [1].

Current regulations for aseptic processing are rigorous, especially in the case of guidelines around cleanroom areas for the manufacture of sterile

products, which must be classified according to the necessary characteristics of the environment. These environments must meet strict classifications in accordance with ISO14644 in order to be categorised as grade A, B, C or D. More personalised therapies that are targeted to meet specific requirements, such as those of a small group of patients, are becoming increasingly popular, generating the need for an increased amount of small batch manufacturing. Equipment for the production of sterile goods must be cleaned, decontaminated and sterilised between batches to prevent contamination of the following batch. If this is not handled correctly, a manufacturer’s start up and shut down process can be significantly delayed. This is a particular challenge for the growing number of contract development and manufacturing organisations (CDMOs) that must be agile enough to handle multiple products for multiple clients within their facilities.

SHAPA Newsletter | 79

Existing cleanroom technologies Sterile manufacturing environments are open to many sources of potential contamination, and thus potential hazards during the manufacture of sterile products, if they are not managed correctly.

Patient safety could ultimately be put at risk should microorganisms, particles or endotoxins enter the manufacturing environment. One of the main sources of contaminants in the cleanroom environment is the operator as the average human carries a multitude of microbes and bacteria.

Other potential sources of contamination include the equipment and raw materials used as well as the environment itself. Multiple technologies have been developed in response to the need to ensure the safe and sterile transfer of APIs and formulation ingredients during aseptic processing.

One such development is isolator technology: isolators provide an airtight barrier around the aseptic processing line and can be employed in cleanroom environments to minimise the risk from contaminants. Current isolator design incorporates unidirectional airflow into the enclosure’s chambers and can provide a specialised environment tailored to the needs of the product; humidity, oxygen, temperature and pressure levels can all be adapted.

Restricted access barrier systems (RABS) are also often used in sterile manufacturing environments.

Several elements must be in place in order for a RABS to be fully functional, including properly designed equipment, management oversight, a quality system and proper surrounding room design to maintain ISO 5. [2] Recent years have seen RABS technology become more widely used, as it provides a barrier between workers and processing lines while 80 | SHAPA Newsletter

offering operators the opportunity to interact with products as necessary. High-efficiency particulate air (HEPA) filtered airflow is also incorporated in RABS technology, significantly reducing the “probability of a non-sterile unit� (PNSU). RABS can be opened to allow process intervention and has also been found to yield similar PNSU data to isolator technology, which must remain closed during operation.

Challenges associated with current technologies Despite their benefits, both isolators and RABS have disadvantages.

Manufacturers using isolator technology may face difficulties when transferring materials in and out of the chamber. A docking isolator may need to be used and the interior may need to be sterilised before materials are transferred, delaying the shut down and start up process between batches. Isolators also have slower start-up times in comparison to RABS, meaning product changeovers are often less efficient.

In comparison to isolators, the closed solution provided by RABS technology is less robust, providing lower integrity chambers. Where isolators can be decontaminated through an automated process, which allows for a high level of biocontamination, RABS rely on manual cleaning processes.

All product or process contact parts within a RABS must be sterilised or steamed-in-place (SIP) prior to use, which creates a more complicated cleaning process than in a traditional sterile area.

As the demand for aseptic processing continues to grow, the disadvantages associated with both technologies pose considerable challenges for the industry. New technologies are now being investigated by pharmaceutical manufacturers as they look for ways to improve efficiencies,

lower costs and reduce the risk of contamination. Many of these technologies work alongside isolators and RABS set-ups, which can allow firms to integrate them into their aseptic processing lines. This can generate significant cost savings for firms that may otherwise have had to overhaul their processes entirely.

The advent of new technologies In response to these challenges, the industry is starting to implement single use technologies and systems. The boost in efficiency and ease of use that disposable parts can provide has led to these technologies being adopted by the industry. Split Butterfly Valve (SBV) technology, for example, has been developed further to create a single use solution for contained materials transfer using a single use passive, a disposable version of the passive mating half of the SBV, and ChargeBag single use packaging.

SBVs are made up of an active half and passive half and enable the transfer of a product from one container, process vessel, isolator or RABS to another without compromising sterility. As well as being used as part of an isolator or RABS set-up, the technology also provides an alternative to traditional barrier techniques and is often considered a more practical option to achieving guaranteed product sterility. The technology can also offer improved ergonomics and reduce reliance on cleanroom environments.

When used, the active half of the SBV is attached to the receiving vessel, while the passive half is attached to the flexible bag or discharging drug container. When the two halves of the disc are brought together a single plate is created, which allows product to flow on the interior surface of each half. This means that when the two halves are detached, the external faces remain clean and can be exposed to the process environment safely.

When the valve of the SBV is sealed, an opening is created between the discs, which means decontaminating gas can be flushed through and

decontamination can take place in a closed environment. Validation occurs using chemical indicators, which confirm full coverage of the enclosure has been attained. This is followed by biological indicators, to ensure a 99.9999% reduction (or 6-log reduction) in bacterial spores has been achieved.

The disposable passive half of the valve, known as a Single Use Passive (SUP) now exists with SBVs. Once docked with the active unit the SUP can be opened, ensuring new single use products are compatible with existing SBV systems in the field.

The need for cleaning and sterilising the passive half of the system is eliminated through the use of these disposable products, which allows for increased productivity.

Due to the importance of ensuring sterility during product manufacturing, there is also growing use of new smart technologies.

Wireless monitoring solutions such

as the VERIFI SMART monitoring technology can provide firms with vital equipment performance data when installed onto an SBV. Maintenance teams, as well as compliance and health and safety teams, can make informed decisions on the management of their maintenance programmes armed with the necessary information provided by monitoring technology.

In addition, multiple manufacturing locations are also now being used by pharmaceutical companies. Much of the development, manufacturing and packaging of products is entirely outsourced, and shipping between countries is often involved as more drug products are moved between facilities. Technologies that ensure the integrity of sensitive products while in transit are now being investigated by manufacturers, as current solutions often pose significant challenges. For example, the use of solutions like fibre or plastic drums with flexible liners

can pose challenges around the filling, sealing, handling and emptying of packages.

Final thought Current technologies such as isolators and RABS offer substantial benefits to manufacturers, but advances in the industry have seen manufacturers looking to develop their containment strategies to remain competitive and ensure compliance. The industry has seen an influx of innovative new technologies, such as single use technologies, smart monitoring and multi-location solutions, in response to the specific manufacturing and handling requirements of sterile products.

As regulations continue to tighten and the need for flexible manufacturing facilities becomes more prominent, the industry will no doubt continue to innovate and use technology to improve their manufacturing processes, so they are fit for purpose now and in the future.

[1] https://www.marketsandmarkets.com/Market-Reports/aseptic-processing-market-53206289.html [2] https://a3p.org/wp-content/uploads/2015/03/article_regulatory_2015_RABS-definition.pdf

SUPPORT

SE RVICE

SALES

TRAI N I NG

DMN UK Ltd

dmn@dmnuk.com

www.dmnwestinghouse.uk SHAPA Newsletter | 81

Leslie David, Conveyor Belt Expert

CONVEYOR BELTING

Who sets the standards?

In this special feature for Process Industry Informer, conveyor belt specialist Leslie David explains who sets the standards and defines the test methods. For those choosing conveyor belts for specific applications he also provides enlightening insider knowledge as to how to not be misled by the claims of belt manufacturers and traders and end up making expensive mistakes.

Who sets the standards?

In the world of processing, conveyors continue to be an indispensable method for moving all manner of materials and products from A to B. The conveyor belt industry itself is a huge, highly competitive, cut throat market. Although there is an abundance of manufacturers and traders, such competition does not necessarily benefit the end-user.

As in any market, the relentless pursuit of orders can and does lead to compromises in safety, quality of performance and operational lifetime. From the buyer’s perspective, mistakes when purchasing conveyor belts frequently prove to be enormously expensive in more ways than one.

Although they might seem to the uninitiated as simply super-sized rubber bands, conveyor belts are surprisingly complex and highly technical pieces of equipment.

There is an enormous variety of destructive materials and demanding operating conditions that conveyor belts have to cope with plus, of course, environmental and safety considerations.

As a consequence, there are many different belt types of conveyor belt construction and an even wider range of 82 | SHAPA Newsletter

rubber compounds designed to protect those constructions. This includes everything from straight-forward wear & tear, rip and impact damage to exposure to heat, oil, chemicals, ozone & UV, extreme cold and fire. With this multitude of requirements comes a bewildering range of test methods and quality standards.

European and International standards Globally there are a number of different quality organisations who set standards for conveyor belting but the most widely accepted standards (for all types of conveyor belt) are those used in Europe. These are EN standards (European Norms), which are maintained by CEN (Committee European de Normalization) and ISO standards (International Organization for Standardization). Both CEN and ISO are independent, nongovernmental organizations and are the world’s largest developers of voluntary international standards. ISO membership consists of the quality standards organizations representing 168 countries. The prefix EN ISO refers to ISO standards that have been adopted in full as a European standard.

In many parts of Europe some specific and longer established DIN standards continue to be more commonly recognised and accepted. This is especially so in the case of abrasion resistant belting. The letters ‘DIN’ stand for ‘Deutsches Institut für Normung’, which means ‘German Institute of Standardization’. They develop norms and standards as a service to German industry and are a highly respected non-profit organization that has been based in Berlin since 1917. A great many DIN standards have been converted into EN or even ISO standards.

Standards for conveyor belts vary between different countries.

However, members of CEN are obliged to implement EN (European standards) as their national standards without modifications and withdraw any of their own national standards that may conflict with them. It is worth bearing in mind that the standards applied to manufacturers in countries that are not members of CEN are frequently found to be significantly inferior or outdated.

Test methods and test standards are not the same When assessing quality credentials it is essential to differentiate between what is simply an approved method

of conducting a particular test (test method standard) and the actual quality or performance standard attained during that test.

The fact that a belt has been tested according to a certain method actually means very little. The most important thing to look at is the actual level of performance achieved during the testing compared against the minimum acceptable level of performance dictated by the test standard. In other words, what was the actual performance? Did it even achieve the minimum requirement? For example, in the case of the ENISO 4649 abrasion resistance testing method, the performance would typically be measured against the performance standards set within ISO 14890.

initially used was “EC Mark” but was replaced by “CE Marking” in the Directive 93/68/EEC in 1993.

When a manufacturer places a CE marking on a product they are declaring, on their sole responsibility, conformity with all of the legal requirements to achieve CE marking.

The manufacturer is thus ensuring validity for that product to be sold throughout the EEA even though the mark does not mean that the product was actually made in the EEA. This, of course, is dangerous. Some conveyor belt manufacturers, especially those in the Far East, deliberately use the CE mark to create an illusion of quality and safety based on the likely assumption that goods with CE marking is proof that the product meets strict EU standards even though no such standards exist.

What to watch for

When choosing which belt to buy it is essential that the technical datasheets provided by manufacturers and traders are used in the decision making process.

However, the fact is that manufacturer’s technical datasheets almost invariably only show the minimum standard demanded by a particular test. Unless stated otherwise, the data shown does not reflect the actual performance achieved during the test and therefore in no way indicates the level of performance that the buyer can expect.

And if they only show the test method reference number then they are pretty much worthless; a fact that applies to the technical datasheets provided by the vast majority of suppliers.

What to watch for

Rather shockingly in my view, a very similar CE mark can frequently be seen that most consumers understandably but mistakenly believe is a genuine CE mark of European conformity. In this case it actually means “China Export”, meaning that the product was manufactured in China.

Designed to mislead? Genuine CE (Conformité

CE Marking Compliance with CE quality standards is increasingly being stipulated by purchasers of industrial conveyor belts even though CE accreditation does not actually apply to conveyor belts. This is because they are not a product category subject to specific directives that are required to be CE marked. Nevertheless, it is still worth having a basic understanding of the role of CE quality standards and how they can be used to mislead.

The letters “CE” used in the CE Marking are the abbreviation of French phrase “Conformité Européene”. This literally means “European Conformity”. The term

Européene) mark and ‘China Export’ mark

Dimensions and tolerances In terms of dimensional standards and acceptable tolerances such as length, width, thickness etc, all textile fabric ply construction conveyor belts are subject to ISO 14890:2013. These specify the dimension requirements for rubber (and plastic) covered conveyor belting for general surface use on flat or troughed idlers.

Different tests for different demands As mentioned earlier, there are many different types of belt and an even wider array of different types of rubber covers, which are most commonly referred to as either cover

grades or cover qualities. The outer covers protect the belt carcass from whatever they are carrying. The primary rubber cover grades used in processing industries are: • Abrasion (wear) resistant • Rip & tear resistant • Oil resistant • Fire resistant • Ozone & UV resistant There are often a combination of factors, such as resistance to fire and oil. However, one that is common to all is the ability to resist abrasive wear.

Abrasion - standards The ability of a conveyor belt to resist abrasive surface wear is usually the single most important factor that will determine its operational lifetime and consequently its cost-effectiveness.

There are two internationally recognised sets of standards for abrasion, EN ISO 14890 (H, D and L) and DIN 22102 (Y, W and X). As mentioned earlier, in Europe it is the longer-established DIN standards that are most commonly used. Generally speaking, DIN Y (ISO 14890 L) relates to ‘normal’ service conditions and DIN W (ISO 14890 D) for particularly high levels of abrasive wear. However, DIN X (ISO 14890 H) is regarded as the most versatile because in addition to resisting abrasive wear it also has good resistance to cutting, impact (from high drop heights) and gouging, usually caused by heavy and/or sharp materials such as ceramics.

Abrasion – testing The test method for abrasion (ISO 4649 / DIN 53516) is actually quite simple. Resistance to abrasive wear is measured by moving a test piece of rubber across the surface of an abrasive sheet mounted on a revolving drum. It is expressed as volume loss in cubic millimeters. For example, in the case of DIN Y (ISO 14890 L) it is 150 mm³.

ISO 4649 / DIN 53516 abrasion testing SHAPA Newsletter | 83

The key thing to remember when looking at abrasion test results is that higher figures represent a greater loss of surface rubber. This means that there is a lower resistance to abrasion.

Conversely, the lower the figure then the better the wear resistance will be.

Rip and tear resistance – testing Rip & tear resistance is not a cover grade in its own right. However, the ability to withstand the forces that rip and tear belts can often be more important than any other physical attribute. Even the strongest, heaviest belts can be punctured and ripped by a foreign object becoming trapped.

A ‘tear’ is best described as what happens when a section of belt is pulled apart in opposing directions. In contrast, a ‘rip’ is what happens when a sharp object punctures the belt and cuts the belt longitudinally as it is pulled against the trapped object.

There are currently no internationally accepted test methods or standards for testing rip resistance. Manufacturers in the USA such as Fenner use a round pin that is pulled through the belt whereas Dunlop in the Netherlands pull sections of belt through a rightangled piece of metal, which they have fondly nicknamed ‘Jack the Ripper’.

Dunlop’s ‘Jack the Ripper’ rip test in action

Fortunately, there is an international standard for tear strength. The ISO 505:2017 test method measures the propagation resistance of an initial tear in textile conveyor belts, either in full thickness or of the carcass only.

This test is intended for application to textile belts in installations where there is a risk of longitudinal tearing.

ISO 505 tear testing 84 | SHAPA Newsletter

Although the method of testing is defined there are, as yet, no standardised performance requirements. The test basically consists of mounting two cut ends of a test piece of belting in the jaws of a tensile testing machine. An initial tear is made in a test piece, which is then pulled apart in opposing directions.

The force necessary to propagate the tear is then measured. Examination and analysis of the multi-peak tear resistance test traces are made in accordance with ISO 6133.

What to watch for

Perhaps not surprisingly, most manufacturers, primarily those manufacturing what are euphemistically referred to as ‘economy belts’ make little or no mention of rip and tear resistance.

Unless specifically designed to resist ripping and tearing, even the thickest, heaviest belts will rip like paper because the type of fabric ply used in the carcass simply is not designed to cope with such forces.

Oil resistance Many bulk materials, especially grain and biomass, contain oils and resins.

When oil of any kind penetrates rubber it causes it to swell and distort.

This results in serious tracking and steering problems, premature wear and ultimately premature replacement. Oils are divided into two distinct sources – mineral and vegetable/animal. The two best recognised test methods for oil resistance (both of which involve almost identical test procedures) are ISO 1817 and the comparable, slightly less elaborate but equally tough American ASTM ‘D’ 1460.

Even some of the biggest manufacturers of belting in the world use the DIN reference number 22102 G when referring to oil resistant belting. This is very misleading because the letter ‘G’ simply denotes oil (or grease). However, the truth of the matter is that DIN 22101 G does not actually contain any requirements, test methods or limits that are specific to oil resistant belting.

This is yet another classic example of how simply displaying a test method reference number is designed to

provide reassurance to the buyer but in reality is meaningless in terms of actual performance.

Oil resistance test methods The ISO 1817 and ASTM ‘D’ 1460 test methods are both used to measure the effect of oil (and other liquids and chemicals) on vulcanised rubber.

Samples of rubber (eg. 100mm X 1.6mm X 2mm strips for the ASTM test) are fully immersed in the relevant test liquid for a specific period of time. The duration of immersion and the temperature at which the liquid and sample are kept can be varied but the most common is either 3 or 7 days at ambient or 70°C.

ASTM ‘D’ 1460 testing

The ambient temperature of the environment is controlled within specific guidelines. Changes in the geometry and dimensions of the specimen caused by absorption are then measured when the samples are removed.

What to watch for

Although there are no actual performance standards in existence, it is still important to look for actual references to the test methods used by the manufacturer/supplier. I find it quite disturbing to note that only one manufacturer (Dunlop again I have to say) makes any mention whatsoever concerning the actual test methods used to determine the oil resistance qualities of their belts.

Fire resistant belting Although fire safety is an enormously important issue, it is quite amazing that such little care and attention is paid during the selection and buying process. Sadly, it often seems that having paper accreditation and certification to avoid culpability is sufficient reason to buy. There are numerous safety classifications,

international standards and many different tests used to measure the self-extinguishing properties of conveyor belts. Test methods and performance standards vary enormously depending on whether a belt is for use above or below ground.

For the processing industry I have focused purely on the requirements for belts being used above ground.

ISO 340 testing

Basic testing The basic test for belting used in normal ‘above ground’ industrial applications is EN/ISO 340. This standard makes the distinction between fire resistance with covers and fire resistance with and without covers. The relevance of “with and without covers” is that over time, wear reduces the amount of fire resistant rubber protecting the inner carcass, which most commonly consists of flammable polyester/ nylon fabric plies. Although no longer used in the current EN ISO 340, the market still commonly refers to grades ‘K’ for testing with covers attached and ‘S’ for testing both with and without covers. This originates from DIN 22103 which was used as the basis during the creation of EN ISO 340.

EN/ISO 340 tests involve exposing 6 individual samples of belt to a naked flame causing them to burn. The source of the flame is then removed.

A current of air is then applied to the test piece for a specified time after the removal of the source of fire. The time it takes for the belt sample to self-extinguish after the flame has been removed is then measured.

The duration of continued burning (visible flame) should be less than

15 seconds for each sample with a maximum cumulative duration of 45 seconds for each group of six test samples. This determines how fire can be carried along a moving belt.

What to watch for

The buyer should still exercise caution even if a manufacturer states that their belt has passed the ISO 340 test. A burning conveyor belt can spread fire a considerable distance in 15 seconds. The real measure of a good quality, safe fire resistant belt is the time it typically takes to selfextinguish. This could and should be as quick as one second. If you are at all unsure of what level of fire resistance you need then it is best to seek expert advice.

Ozone & Ultra violet resistance Although not commonly known (or even mentioned by most manufacturers) an absolutely essential quality that all rubber belting should have is the ability to resist the damaging effects of ozone and UV. Although not an actual cover grade in its own right, there is no question that all rubber belts need to be fully resistant to ozone and UV light. This is because at ground level, ozone becomes a pollutant that attacks rubber by increasing the acidity of its carbon black surfaces and causes reactions to take place within the molecular structure of the rubber.

This has several consequences including significant surface cracking and a marked decrease in the tensile strength. Likewise, UV light from sunlight and fluorescent lighting also accelerates deterioration. This is because ultraviolet produces photochemical reactions that promote the oxidation of the surface of the rubber, resulting in a marked loss of mechanical strength. Ozone and UV combined really are invisible belt killers.

EN/ISO 1431 international standards To scientifically measure resistance to ozone, samples are placed under tension (eg. 20% elongation) inside the ozone testing cabinet and exposed to highly concentrated levels of ozone for a period of time (eg.up to 96 hours).

Ground level ozone and UV exposure causes rubber to disintegrate

Samples are closely examined for evidence of cracking at two-hourly intervals and the results carefully measured and recorded. Experience has shown that for the rubber to be adequately resistant the pass criteria needs to be that there are no signs of cracking after 96 hours (@ 40°C, 50 pphm and 20% strain) inside the ozone cabinet.

What to watch for

As I mentioned earlier, despite its crucial importance, ozone and UV resistance is very rarely, if ever, mentioned. This is almost certainly because costly anti-ozonants need to be used during the mixing process of the rubber compounds. A recent series of samples of rubber belt originating from Asia revealed that every single sample had virtually nil resistance to ozone and ultraviolet. My advice is to make ozone & UV resistance a constant requirement when selecting any rubber conveyor belt.

Conclusions Quality standards and testing in the conveyor belt industry is a huge and often complex subject. What I have endeavoured to do is simply provide a basic guide. Never assume that seeing the presence of test method reference numbers or the logos of quality organisations necessarily means what they are designed to indicate. It is always worth taking the time and trouble to ask questions and request evidence of best practice and, above all else, actual performance.

Raw materials alone make up some 70% of the cost of manufacturing so in the case of conveyor belts, highly attractive pricing should start the alarm bells ringing. Taking that little bit of extra care could easily save your company an enormous amount of time and money.

SHAPA Newsletter | 85

Considerations when sourcing

When clients first consider Pneumatic Conveying as a method for handling bulk material and hear the principle of air blown into an enclosed pipe, they often expect the process to cause particle turbulence and potential damage. This initial view is far from the truth, if the right type of Pneumatic Conveying technology is specified for your process, as well as the material it will convey.

The purpose of this article is to outline the basic, but yet very important considerations, for when approaching a supplier to provide Pneumatic Conveying technology.

Types of Pneumatic Conveying Pneumatic Conveying has predominately two category types – Lean Phase and Dense Phase Conveying.

Core Differences

The type of conveying method chosen will determine how the materials travel through the process plant. Although the pipes are totally enclosed, through extensive process and formalised material characteristic testing, an understanding on how different materials react between the two types, can be demonstrated by an experienced supplier. There isn’t a ‘one process’ suits all.

Lean Phase Lean Phase Conveying uses a large volume of air and higher velocity, to move in comparison, a small amount of material. As a result, the material is effectively carried through the pipe, while being suspended in air.

Typically, this method is preferable for short distances and non-abrasive materials, either powdered or granular in nature.

With either Pneumatic Conveying categories, material is commonly transferred from a single collection point to either a single or multiple reception points and when installed as a full system, will include various components, such a range of pumps, valves and pressure vessels, depending on the material and distances conveyed.

The design of Lean Phase Conveyors offer the benefit of being compact, therefore utilising less space than Dense Phase Conveyors, as well as providing quicker installation.

For the operator, the equipment is simple to use and carry out maintenance on – an important factor if the material handled causes regular ‘wear’.

86 | SHAPA Newsletter

Fragile materials that are conveyed through a Lean Phase Conveying system can often become degraded or damaged, leading to an increase in dust within the conveyor and also further down the process.

Depending on the process, this dust may change the properties of the material being conveyed, or become a potential explosion risk, often in both cases due to segregation. Such dust generation concerns can be mitigated or avoided by using a Dense Phase Conveyor.

Over a period of time, the higher conveying air velocity of Lean Phase Conveying may also cause ‘wear’ on the pipes if the material is not suited to this method of processing. When the wear is excessive, premature failure of the plant could occur, resulting often in lost production,

environmental dust release and expensive maintenance. With the correct application evaluation, it is possible to remove or mitigate all of these risks. It is therefore very important to seek consultation from a specialist who can confirm that the material handled is appropriate for this method of Pneumatic Conveying.

Other aspects to factor-in are the design of the pipeline and choice of bends and valves. Where possible, keep the pipeline simple and accessible. Quick access for cleaning and maintenance needs to form part of the overall layout. Quality pipeline divertors, correctly selected for the application, such as the ProDV bypass valve or parallel tunnel diverter PT45 valve, will provide peace of mind on the exact, reliable control of the shut-off/ supply of material.

Dense Phase In comparison to the process of Lean Phase Convening, Dense Phase Conveying uses higher levels of pressure, but lower volumes of air, across a much longer pipeline. Consequently, the material is pushed through the pipe and bends, in a slug/pluglike behaviour. This results in the material being conveyed at much lower velocities than Lean Phase Conveying - often of the order 3 to 5 times lower.

Dense Phase Conveying is suitable for a variety of materials, ranging from fine cohesive powders, abrasives such as pulverised coal through to coarse granular products.

One of the most important considerations for Dense Phase Conveying is ensuring the conveying velocity at the start is set correctly for the material being conveyed. If the pressure and air volume is not set appropriately, it could lead to a poorly performing conveying system. Industrial scale conveying trials in pipelines with a bore of at least 80mm and a distance at least half of the intended distance for the users application, should be carried out to ensure a welldesigned, long lasting system.

Typically, Dense Phase Conveyors experience minimal wear on the pipe and bends, allowing for less maintenance and long system life performance. Often the wear in Pneumatic Conveying Systems is quoted as being proportional to the velocity3. For the case where the material is Dense Phase Conveyed on average at a velocity 5 times lower than the Lean Phase System, then the wear will be 53 = 125 times lower. This is often over looked, but of course means that bends that last only 1 month in a Lean Phase System, could last 10 years in a Dense Phase

SHAPA Newsletter | 87

one. Experienced providers will be able to assist the user with the correct choices according to the operating requirements.

Schenck Process UK is home to our Clyde Process Dense Phase Pneumatic Conveying systems, part of the ProPhase® range and are regarded as one of the world’s leading product brands for this technology.

What differentiates the Schenck Process range of Dense Phase Pneumatic Conveyors is the continued research and development of our products and solutions, a live and extremely busy industrial scale testing centre, as well as our 40-year experience in specialist design, testing and engineering.

All of this allows for: Simplicity, Reliability and Flexibility. In nearly all cases, each system is engineered to be bespoke to the process requirements, using standard, proven components, products and design approaches.

Before Schenck Process embark on any project, we will work with clients to truly understand their process needs, what issue they are encountering, what materials are handled, test the material characteristics and ensure we engineer a system that provides optimum performance and longlife operation.

Schenck Process is a global and trusted supplier of bulk handling industrial equipment, who support a variety of sectors including Food, Chemicals, Plastics and Pharmaceuticals.

Mining, Steel & Metals, Sand & Gravel, Cement & Gypsum, Grain & Agriculture, Transport & Automation and Utilities.

• Full consultancy and engineered design • Material and process inspection, as well as testing • Introduce quality processes that removes a customer’s ‘anguish’ • UK, trusted Clyde Process product brand, supplied globally by Schenck Process • Focused on offering efficiency, reducing maintenance and overall operational costs • Project management available from start to finish – world wide • Service packages and user training

Providing New Equipment, as well as Maintenance and Testing Services, with Systems for Conveying, Weighing, Feeding, Screening, Powered Processing, Automation, Air Filtration, Bag Filling & Discharging, as well as Components and Spares.

For more information on Schenck Process systems, please contact: enquiries@ schenckprocess.co.uk | www. schenckprocess.com/uk

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Dr Rob Berry, Senior Consultant Engineer, The Wolfson Centre for Bulk Solids Handling Technology

A review of the

pros and cons

of different types of conveyor and their suitability for transporting materials with different bulk flow properties.

Overview of different conveyor types There are seven principally different forms of bulk conveyor as described below; • Belt conveyor, a continuous belt nominally rubber on which the bulk solid is deposited transported and discharged at the end of the belt assisted by a scraper.

• Screw conveyor, a screw in an open trough, whereby rotation of screw causes bulk solid to slip down the front face and avalanche forward ahead of the screw, to a discharge port at the end of the trough.

• Chain (or En-masse) conveyor where a continuous flighted metalic chain in a casing is used to drag a bed of bulk solid down an enclosed channel to a discharge point.

• Vibratory conveyor, a metallic tray, that is vibrated at a high frequency low amplitude in a diagonal forward motion, to cause particles to vibrate along the tray to a discharge point.

• Pneumatic conveyor, a closed pipe down which bulk solid is conveyed in air, using either a positive pressure or a vacuum to discharge into a receiving hopper with a filtration system to separate the air and solids. System can be lean phase high air low solids, low pressure or dense phase high solids low air at high pressure.

• Air slide, an air permeable membrane (with a pressurised plenum chamber below) in the base of a channel, which is filled with bulk solid that is fluidised by the air flow causing gravity flow down a shallow decline (1 to 15°).

• Gravity chute, a declined chute at an angle slightly steeper than the wall friction angle of the material that relies on gravity to cause flow to a discharge point.

90 | SHAPA Newsletter

Fundamental bulk flow properties affecting the different conveyor types There are several bulk flow properties that effect the flow behaviour in the different types of conveyor, and these are explained below. The key flow properties are the: • wall friction angle, i.e. the angle that a surface covered in bulk solid can be inclined too (see fig 1a), before the material slips down the wall.

This can be measured in a wall friction test and is presented as a wall friction locus (see fig 1b).

The blue wall locus is typical of a free-flowing low wall friction bulk solid with a friction angle of 12° that is independent of stress level, or depth of fill on surface. The red locus represents a fine “sticky” bulk solid, where friction angle varies with stress, with a friction angle of 90° for a fine layer reducing to 35° as bed depth increases to create a hydrostatic stress of 8kPa. • wall adhesion or “stickiness” i.e. the potential for a material to stick and build up on a surface, which is measured as the intercept of the wall friction locus with the shear stress axis (see fig 1b). Here a wall adhesion of 0.5kPa would require a layer thickness of 0.05m for a bulk solid of 1000kg/m3 bulk density to discharge from a vertical wall under itself weight.

• fluidisation properties are significant for air assisted conveying, an aeration column is used to measure bed expansion and observe fluidisation behaviour. The Geldart Chart (see fig 2) gives a brief summary of the effect of particle size and difference in solid and fluid density on the fluidisation behaviour. Note while this may be useful for air slides, for

pneumatic conveyors, full scale trials are essential for reliable system design.

• flow function, the result of a shear cell test, to measure the flowability (cohesive strength) when a bulk solid is sheared internally see fig 3, shows the standard flowability indices and compares these to approximate limits for handleability of various conveyor types.

Generally pneumatic conveying is best suited to freeflowing materials, screw and chains for free and easy flowing materials and belts for cohesive bulk solids.

• angle of repose (dynamic) effecting the inventory that will be stored in the width of the belt (see fig 4a), the volume advanced by a screw (see fig 5). A freer flowing material forms a shallower angle than cohesive material.

A fluidised material will form a horizontal surface.

a)

b)

Fig 1 Wall friction a) slip down a wall and b) Wall friction loci

Fig 2 The Geldart chart describing fluidisation behaviour as a function of particle size and the density difference between solid and fluid

Fig 3) The flow function and suitability of different conveyor types Pros and cons of the different conveyor types: Gravity chutes require height but are otherwise low cost and can provide good containment. Key issues are; limited ability to control feed rate, potential for material to build-up on the chute surface if bulk solid is very cohesive or “sticky” leading to blocking and flooding/ flushing for free flowing aeratable materials.

Belts provide; low operating cost transport over short to long distances (10 to 10,000m), gentle handling suitable for a wide range of flow properties and are relatively easy to clean. The downsides are; routing restrictions and poor containment, straight line and slight inclines between transfer points, the high capital costs of all components, need for careful setup for reliable operation and the presence of a return path that must be cleaned. Note that special belting solutions such as pouch belts see fig 4b can route round corners and give good containment, but with a significantly reduced transport capacity per unit length of belt. For elevation, the contact friction against the belt rubber (in presence of vibration) limits conveying angle, but textured belt surfaces can increase this. Steep elevation angles can be achieved with sandwich belts, walled belts or bucket elevators. Metallic apron conveyors can be used for high temperature environments. In terms of material flowability belts can handle the widest range of materials issues are sticking and cleaning problems for very cohesive materials and dust emissions at transfer points plus windage (for open belts), for free-flowing materials.

Screws provide; good containment, a minimum of moving parts, no return path and ability to convey against a positive pressure or high temperature environment.

The downsides are; limited conveying distance (30m per screw), straight routing restrictions and are not fully selfclearing (material retained in trough screw clearance).

Screw conveyors can be used to elevate materials at up to typically 30° (usually with a reduced pitch to increase the helix angle). When elevating, screw conveying efficiency is reduced as incline increases (see fig 5b) because the helix angle reduces, so friction against flight face lifts more material over shaft to drain back to the previous pitch, whilst the dynamic angle of repose becomes closer to horizontal reducing forward motion. Note that highspeed screws (rotating above the critical “wall of death” speed) can be used to elevate materials vertically. The material issues are the potential for; particle degradation and poor conveying of high friction “sticky” materials, that adhere to the screw flight turning with the screw.

Chains (see fig 6a) provide; conveying over relatively long distances (100m +), good containment, low particle degradation as flights contact a relatively small area of the transported bulk solid and can feed elevated temperatures. Downsides are; metal on metal contact of chain links in product that could cause contamination, a return path that is difficult to clean, routing restriction (horizontal with transition to an incline or vertical rise) and high capital cost of all components. Regarding flow properties, friction between moving bulk solid and channel walls effects conveying efficiency and drive power. Vertical/elevated conveying achieved by increasing flight area in contact with bulk solid in the channel (see fig 6b).

Vibratory trays (see fig 7a) provide; conveying over relatively short distances (20m per conveyor), low degradation, can operate at high temperatures and SHAPA Newsletter | 91

elevation can be achieved with a spiral tray.

Regarding the bulk properties, are suitable for free flowing non segregating materials (i.e. larger particles convey more efficiently than fines). Cohesive materials tend to stick to conveyor over time, with potential to then discharge as agglomerated lumps.

Pneumatic conveyors provide; effective conveying in a lean phase for a wide range of material flow properties (except very “sticky� solids) over distances of up to 100 - 300m, good containment of the product and can feed into high pressure or temperature environments. Inert gas can be used for conveying explosible materials. The downsides are high capital and running costs.

Dense phase gives lower running costs, but only a limited range of bulk solids will convey in this mode (generally, freer flowing materials with narrow particle size distributions). Care must be taken over pipe routing to avoid an excessive number of bends, and to ensure pipes are either horizontal or vertical (no inclines), with enough

a)

horizontal straight prior to bends or vertical rises to first accelerate particles to fully suspended flow.

Other issues are the potential for either particle degradation (and fine particle generation) or pipe wear at bends depending on whether the particles are harder than the pipe wall. For very sticky or plastic particles, bend impacts can lead to particle adhesion to the pipe wall, gradually reducing pipe bore increasing the conveying velocity and build up rate until eventually the conveyor becomes blocked.

Air-slides (see fig 7b) provide; gentle handling, good containment, and are suitable for conveying over distances of 10m plus, per slide. However, technique is only suitable for materials that fluidise easily, Geldart groups; A and B (see fig 2). The former group requires less air but maybe difficult to control or subsequently pack as slow deaeration may cause contents to settle in pack over time, leading to underfilling and pack stability issues if stacked.

b)

Fig 4 Belt conveyor a) angle of repose and idler configuration control volume transported per m of belt and b) Pouch conveyor

a) 92 | SHAPA Newsletter

b)

Fig 5 Mechanics of screw conveyor for; a) horizontal (fill level at approx. 45%) & b) inclined transport (fill level reduces with increasing inclination angle e.g. 30% at 30°)

a)

b)

Fig 6 chain conveyor a) b) different flight configurations for inclined conveying of different materials

a)

b)

Fig 7 a) Vibratory conveyor and b) air slide Summary There are a wide range of bulk solid conveyors available, for free-flowing materials it is often equipment wear, particle degradation or dust issues that provide potential challenges. However, for poor flowing bulk solids, where cohesion maybe generated either through the presence of; surface moisture (that binds particles together), or fine particles (below typically 100Âľm diameter where interparticle forces start to dominate over gravity forces), a knowledge of the bulk flow properties is usually essential for the design of efficient trouble-free conveyors.

SHAPA Newsletter | 93

v

Following the success of our 2019 event, we are delighted to announce our 2020 categories. These awards are open to all UK registered member and non member companies and institutions operating in the Solids Handling Industry. Application forms are available direct from the website and winners will be announced and presented at the awards ceremony in the evening of the 22nd April 2019. Closing date for applications 29th February 2020.

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