AGRICULTURAL SECTOR
TOBACCO CURERS Tunnel Strath Brown, the founder of Brown Engineering Group (initially J. S. Brown Industries), developed the tunnel concept in the 1970’s. Since then the systems have progressively been optimized and the efficiencies have increased to what they are today. A standard 30Ha tunnel now only requires as little as 0.7kg of coal per kg of dry tobacco produced and can run on 15KW per hour of electricity (20KVA Generator). As a comparison, conventional barns use between 3-4kg of coal per kg of dry tobacco. The savings on coal, electricity and labor make a tunnel a worthwhile investment. A tobacco tunnel is a continuous system which means that hot air is blown into one side of the tunnel and is pushed through the tunnel to be exhausted at the end. Some of the moist air is returned to the heat exchanger room and mixed into the hot air stream so that the humidity is controlled in the tunnel. Brown Engineering Group offers a range of tunnels from 10Ha to 120Ha with different configurations and options. We also have three types of heat-sources to choose from, a dry heat exchanger, a kettle and radiator system or a boiler and radiator system. We offer 4 layout options depending on the farmers building site and requirements: • • • •
Single Pass or Straight tunnel Double Pass or Turnaround tunnel Triple Pass Tunnel Custom design
BEG provides all the drawings and equipment. A project manager is allocated to your project and will guide you through each step of the build.
Chongololo The chongololo system, like the tunnel, is a continuous curing system where heat is introduced in one barn and only exhausted from the last barn after picking up as much moisture as possible throughout the system. Instead of moving the tobacco through the curing unit, doors in each barn are used to control the airflow through the system. For a chongololo , Brown Engineering Group provides three standard options, 12Ha, 18Ha and 26Ha units. Each unit can use either a dry heat exchanger or a kettle and radiator system. We supply all the drawings, steel work and electrics required for the unit including the vents, doors, roof, fans and heat exchanger. If a concrete roof is preferred, we will provide the design and required reinforcing. Alternatively, a corroboard ceiling can be used.
Conversions Conventional barns and downdraught barns are becoming less and less viable to cure tobacco. They are too inefficient, so it is becoming increasingly difficult to cover the cost of running them as margins on tobacco sales keep decreasing. A solution Brown Engineering Group provides is to convert these older systems into chongololos or single heat source systems. Up to 16 furnaces can be replaced by a single dry heat exchanger or kettle and radiator. We have standard designs or can offer custom designs to convert these old systems into more efficient chongololos or single heat source systems. We supply all the drawings, steel work and electrics required for the unit including the vents, doors, roof, fans and heat exchanger.
Refurbished Sometimes a farm has an old system on it that is rundown or not working. Brown engineering can perform a survey and provide a quote to renovate the system. We will help you understand how the old system worked and can supply all the necessary equipment and drawings to modernize the unit and get it up and running again.
Non-Standard Farmers often have their own unique requirements, a selfdesigned system or a mixture of old buildings that need to be incorporated into a new system. We are happy to help with the design and provide anything that is required including doors, vents, heat exchangers, trollies and electrics.
Curer Unit Equipment We stock a vast array of curing unit equipment and spares. If we don’t have the equipment in stock, we should have the raw materials to make it up as soon as possible. • Allububble • Automation Kits • Boilers • Chong Doors • Corroboard • Curing Fans • Dry Heat Exchangers • Electrical Components • Foam Insulation • Furnace Kits • Pumps • Radiators • Rails • Sliding Doors • Stokers • Switch Boards • Tobacco Clips • Traverses • Trolleys • Variable Speed Drives • Vents and Control Doors • Weighbridges
CURER FAQ’s What size curer do I require? The technical sales representative at Brown Engineering will guide you through the calculations to ensure you know how many hectares your unit will be able to cure. We will go through the assumptions with you and will take into consideration your specific requirements and growing conditions on your farm. The curer is sized for a single planting. If you do irrigated and dryland in one season, then it will be able to double the amount. An example which shows some typical assumptions and the formulas used is shown below. The example considers a 30Ha tunnel. If you have 2 plantings in one season the tunnel will do 60Ha. However for regions with a thinner leaf or if a high wet bulb is used, curing time could be reduced to 6 days in the tunnel and 1 day in a green bay, which would mean that the same tunnel would be able to do 21 Trolleys per day which is 35Ha.
Recommended Size of Tunnel Required to Cure 30Ha Hectares Required Assumptions: Plant Population (Plants/Ha) Ripening Rate (leaves per week) Required Days Cure (excl. Green Bay) Max Clips per Trolley Max Leaves Per Clip Number of Leaves Per Day Trolleys Per Day Total No of Trolleys Req in Tunnel
Ha
30
p r
15200 2.6
d
7
c l
174 54
lpd = Ha x p x r/7 tpd = lpd /l /c = tpd x d
169,371 18 126
Which system gives you the best cure? This is a question often asked. However, it must always be considered with the cost of the cure. Profit is selling price minus cost price. So, the ultimate goal is to get a high selling price and low-cost price per kg of tobacco. All systems if run properly will give you a very good cure. A tunnel gives you the lowest cost price per kg of dry tobacco. It will cure very nicely if uniform tobacco is being loaded into the unit from day to day and a few basic curing principles are executed correctly. The same applies to a chongololo as it is also a continuous system. It is a bit more expensive to run than a tunnel, but the advantage with the chong is that you can vary conditions slightly in each barn depending on the tobacco by adjusting some vents. This gives you a bit more control if the tobacco is not uniform. Some of the best curing units are the single heat source units, where there is a fan in each barn that draws hot air from a common duct. There are four doors to control the amount of heat, the amount of ambient air, the return air and the exhaust. These systems are not continuous so they are not as efficient as a chongololo or tunnel but there is more control over the tobacco in each barn and the tobacco does not have to be uniform from day to day.
What is the most cost-effective system to build? The initial cost per hectare is considered when you want to build a curing system. However, the running cost per hectare in the following seasons must also be considered to see which option has the best return on investment. A chongololo is a high-pressure system and uses large fans. An 18Ha chong at max uses about 13KW which is 0.72KW per hectare compared to a 30Ha tunnel which only uses about 10KW which is 0.33KW per hectare. This shows that a tunnel uses less than half the amount of power than a chong. If the electricity must be produced by a generator, the cost saving of a tunnel is even larger. Another aspect to consider is the amount of scrap produced. Conventional barns or a chongololo that uses tier poles results in about 5% loss due to scrap. The tobacco is reaped into clips, stacked onto a trailer, lifted
past tier poles into the barn. Then after curing tobacco is passed down through tier poles, stacked onto trays, carted to the shed then unloaded from the cart into stick bulks. For a trolley system, the tobacco is loaded onto the trolley and only touched again when it is unloaded into stick bulks. This reduces the amount that the tobacco is handled, and scrap loss can be as low as 0.3%.
What is a dry heat exchanger? A dry heat exchanger is one that does not use circulating water to transfer heat from a furnace to the air. A kettle and boiler use a pump to circulate hot water through a radiator. Fans blow air through the radiator to heat up the air. A dry heat exchanger uses a steel shell around the furnace. Air is blown over the steel shell to pick up heat. The shell also incorporates ribs or pipes to increase the surface area for more heat to transfer to the air.
What is the difference between a kettle and a boiler? A kettle and a boiler look the same but operate slightly differently. They both use a pump to circulate hot water through a radiator. Fans blow air through the radiator to heat up air. A boiler is sealed by a pressure relief valve which means that when heat is supplied, the pressure increases in the boiler up to about 3 bar. This increase the boiling point of water in the boiler to about 130 degrees Celsius. The water that circulates through the radiators can reach 120 degrees Celsius. A kettle on the other hand is not sealed, it has a header tank which ensures the kettle is always full. The pressure does not increase in a kettle, so the boiling point of the water is only about 100 deg Celsius. This means that the water circulating through the radiators only reaches about 98 deg Celsius. The advantage of not having a pressured system is that the steel plate used to make the kettle is lighter than that of the boiler. It also means that a kettle does not need a government inspection every 3rd year. These two points make it cheaper to buy and operate. With our new radiators, the water temperature of 98 deg Celsius through the radiator is enough to heat the air up to a maximum of about 85 degrees Celsius which is ample for tobacco curing.
What are the advantages and disadvantages of the different types of heat sources? The dry heat exchanger is seen as an economic short-term solution. A kettle or boiler is ideal for a longterm investment. Many boilers installed before 2005 are still in use today. The total power and efficiency of the three different systems are very similar. Please see the table below for a comparison.
Boiler Kettle Dry Heat Exchanger
Approx. Cost/KW
Efficiency
Lifespan (years)
Cost/KW/Year
US$ 21.80 US$ 18.30 US$ 7.20
90% 90% 90%
20 20 5
US$ 1.09 US$ 0.92 US$ 1.44
Service & Backup Before the curing season starts, Brown Engineering offers pre-season unit inspections in Zimbabwe, Malawi and Zambia. Please contact us if you would be interested in this service. During the season, we offer around the clock backup service with dedicated teams on call. We plan 6 months in advance and hold enough stock for any situation. In 2018, a large section of a tunnel in the Headlands burnt down. The Brown Engineering teams responded and within 5 days the tunnel was operational again. The ceiling, trusses, electrics, trolleys, roof and clips were swiftly replaced.
TOBACCO GRADING AND HANDLING Brown engineering manufactures all the equipment necessary to handle, grade, and bale your tobacco after it is unloaded from your curer.
Slat Pack Box and Jack The slat pack box has been designed for farmers who want to pack and mature their tobacco into slat packs during the curing season for grading at the end of the season. A bale press can be used for the same job but is more expensive than the slat pack box and jack.
Bale Press The bale press is used to press tobacco into bales, ready for transport to the floors. Either a hand bale press or an electric bale press can be chosen. The electric bale press saves on time and labour and can reach a production rate of 1 bale every minute.
Baling Boxes There are 3 baling box options, the economy bale box, the standard bale box and the jumbo bale box. The economy bale box is paired with the economy hand press while the standard can be used with our electric press. The jumbo bale box is used to press 500kg slat packs with the jumbo electric press. This offers a higher density storage option but requires a forklift to stack the slat packs. We offer baling boxes with 2 or 4 wheels and an option for a complete bale box setup on rails with a travers and bale box scale.
Conveyor Grading Tables 6m, 9m, or 12m conveyor grading tables are available. The tables decrease the labour requirement during grading and increase the grading’s team throughput and efficiency.
Grading Trommels Hopefully the amount of scrap produced is minimal, however if it is not then the grading trommel is vital to sift through the scrap and pull out the extra kgs of tobacco worth selling.
TOBACCO SMALL SCALE FARMERS
Brown Engineering Group provides equipment for small scale tobacco farmers which increases barn efficiency. Flue pipes evenly distribute heat around the barn. V- Slots shape the bottom of the furnace and allow the builders to build a slot into the furnace floor. Furnace doors are needed to seal the entrance to the furnace so that air is drawn through the V-slot into the fire which aids burning. V-slots and furnace doors greatly increase the efficiency of the furnace. We also manufacture Kurt machines which make reaping easier.
HEATING AND FURNACE EQUIPMENT BEG Designs and Installs a multitude of heating solutions for different industries. There are three heating categories that can be considered:
Heating Air Although BEG has developed a lot of knowledge on heating systems from the tobacco industry, we have used the same equipment and principals in other applications such as heating air for drying grain, macadamias, onions, peppers, garlic, herbs and wood. We have developed practical and reliable solutions to monitor and control temperature and humidity and can design them into any system you require. We have three types of heat-sources to choose from - a dry heat exchanger, a kettle and radiator system or a boiler and radiator system. Along with the heat exchanger, we supply: - Temperature Control Equipment - Furnace Bricks - Furnace Fan - Stokers - Radiators - Electrics - Variable Speed Drives - Fans ranging in size from 0.5Hp to 30HP We can supply either axial flow fans with contra rotation options or centrifugal fans. The fans can be either chain, belt or directly driven. Please contact us for more information.
Heating Water Heating water for domestic use, agricultural use or industrial use are all options available at BEG. We offer the following boilers and kettles 75l, 250l, 300l, 530l, 1000l, 1325l, 2700l, 3390l, 3700l, 4300l and 4700l. Provided with the boilers or kettles are all the temperature control systems, the furnace bricks, the stoker, the furnace fan and the pumps. Some example projects include heating water to pump through a greenhouse to warm the environment for roses, heating water for a crocodile farm, and domestic showers for a safari camp.
Producing Stream BEG produces boilers capable of producing up to 1100kg of steam per hour at 3 bar pressure. Provided with the boilers are all the temperature control systems, the furnace bricks, the stoker, and the furnace fan.
MISTING SYSTEMS Brown Engineering Group is a proud partner of Tecno Cooling Systems, an Italian company that specializes in misting systems. The Misting systems are used to control the humidity or temperature of an environment by spraying high pressure water through small nozzles which creates a fine mist. As the water particle evaporate, the humidity is increased, and the environment is cooled by a process called evaporative cooling. Long lines of misters are used in warehouses or packsheds with humidity probes to automatically monitor and control the humidity. Fans can also be used to circulate the cool moist air. BEG stocks all the components and can design and install a system according to your specifications. For more information, please visit www.tecnocooling.com
TRAILERS Combine Harvester Header Trailer We have designed a 14m trailer to carry the head of a combine harvester. The trailer can carry up to a 5-ton head and can easily be towed behind a tractor or combine. This enables the combine to drive down small farm roads hassle free.
Reaping Trailer This is a versatile 2-wheel trailer that can be linked with up to 4 other trailers in a row. The trailer can be fitted with rails to carry a tobacco trolley on it or can have a wooden deck, or a wood deck with sides, or fitted with a removable 1000l water bowser. One trailer with different add-ons makes a cost-effective multipurpose trailer.
Standard Farm Trailer The standard farm trailer is a 6m or 4m heavy duty 4-wheel trailer. The trailer can be fitted with either a wooden deck or a steel deck. Sides are optional.
Water Bowsers &Tanks Brown Engineering manufactures a standard 2000l farm water bowser with a single axle. Other options include a farm trailer mounted with a flat bottomed 1000l plastic tank, or a farm fuel bowser with a 1000l horizontal steel tank complete with either a 230V fuel pump or a 12V fuel pump with filter, meter and easy fill hose.
WIRE PRODUCTS Bale Ties Brown Engineering manufactures 89”, 90” and 91” bale ties used in the cotton industry. Each batch of wire is tested before it is used for the manufacture of the bale ties to ensure it passes the international standards. Both the breaking strength and the knot strength are tested. In full production, BEG can manufacture up to 140 000 per week.
Tobacco Clips The manipular clip is a wire product used to hold tobacco leaves on a trolley or in a curing unit while the tobacco cures. The manipular clip was invented by Strath Brown and was the initial product which kick started the company. It revolutionized the tobacco industry by reducing the amount of labour required to reap tobacco, and it greatly reduced the amount of scrap produced due to handling. The Talita clip is an alternate to the Manipular clip which utilizes springs to grip tobacco in place. The Talita clip is also manufactured by BEG.
PHONE: +263 242 665313 /+263 242 664795 PHONE: +263 242 665313WHATSAPP: /+263 242 664795 +263 782761973 WHATSAPP: +263 782761973 EMAIL: sales@be.co.zw EMAIL: sales@be.co.zw WEBSITE: www.be.co.zw WEBSITE: www.be.co.zw