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Industrial heating – Silckone heaters
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Industrial heating – Silicone heaters 2 Silicone elements - Standard sizes
VärmeKabelTeknik
Part.no
Width
Length
Power
Voltage
40.0180.0
25
900
50
12
40.0140.0
25
95
15
40.0110.0
25
100
40.0120.0
25
40.0125.0
Part.no
Width
Length
Power
Voltage
40.0065.0
100
100
100
240
24
40.0070.0
100
200
200
240
25
24
40.0075.0
100
325
325
240
200
26
24
40.0080.0
100
500
500
240
25
325
80
24
40.0085.0
100
625
625
240
40.0035.0
25
500
125
240
40.0090.0
100
900
900
240
40.0038.0
25
2000
500
240
40.0030.0
100
1400
1200
240
40.0260.0
38
50
15
24
40.0235.0
100
1400
1400
380
40.0165.2
37
710
200
240
40.0245.0
100
2000
2000
240
40.0130.0
50
100
50
24
40.0535.0
100
2450
3000
240
40.0040.0
50
200
100
240
40.0395.13
120
1300
400
240
40.0045.0
50
325
175
240
40.0395.17
120
1750
525
240
40.0050.0
50
500
250
240
40.0395.23
120
1300
400
240
40.0055.0
50
625
325
240
40.0095.0
150
150
250
240
40.0060.0
50
900
500
240
40.0285.0
150
600
700
240
40.0200.0
50
1000
250
240
40.0290.0
150
900
1100
240
40.0205.0
50
1500
375
240
40.0295.0
150
1200
1500
240
40.0210.0
50
2000
500
240
40.0100.0
200
200
500
240
40.0212.0
50
3000
750
240
40.0265.0
200
500
500
240
40.0250.0
50
3000
1000
240
40.0300.0
200
600
1000
240
40.0396.3
70
712
200
110
40.0305.0
200
900
1400
240
40.0396.7
70
1067
300
110
40.0185.0
200
1000
2000
240
40.0390.1
75
530
125
24
40.0310.0
200
1200
2000
240
40.0390.4
75
680
125
24
40.0580.0
250
600
540
240
40.0390.6
75
800
125
24
40.0585.0
250
930
835
240
40.0390.9
75
960
125
24
40.0105.0
300
300
900
240
40.0391.1
75
1100
125
24
40.0262.0
300
600
600
240
44.0732.1
Glue RTV‐732
90 ml
200 °C
40.0590.0
335
930
1120
240
44.0732.2
Glue RTV‐732
310 ml
200 °C
40.0590.1
335
1000
1200
240
44.0736.1
Glue RTV‐736
90 ml
260 °C
85 816 33 Electronic thermostat‐15 ‐ +150°C for DIN‐rail
44.0736.2
Glue RTV‐736
310 ml
260 °C
85 816 43 Electronic thermostat ‐15 ‐ +150°C for wall
VärmeKabelTeknik Velox Silicone Elements: Installation Guide
Industrial heating – Silicone heaters 3
Easy installation Ease of installation, great flexibility and low weight to‐ gether with a long service life make silicone heating elements ideally suited for industrial, medical, telecommunication and military applications. The elements can be glued, strapped or clamped to the surface to be heated. As a rule they are not moisture resistant. If desired, however, completely waterproof elements can be supplied. Connection cables are available in a variety of designs. We can also supply elements that have a built‐in thermostat. These cables and elements are available on request, and we will be glad to quote you a price for them. The silicone elements can also be designed to customer specifications for particular shapes. Also available is a type of element which is divided into distinct sections, where each section of the element is connected up separately.
Mounting methods Mounting of silicone elements is generally done by using glue, supporting joints (tension springs or straps) or screw joints.
For gluing Velox silicone elements, we recommend either of the following two types of 1‐component silicone glue: RTV 732 and RTV 736. Glue consumption is approx. 300 grams per square metre. Clamping and strapping are two methods best suited to applications where you wish to be able to remove the elements without causing damage to them. The elements fit smoothly and tightly around a cylindrical metal surface for maximum heat transfer. They are attached to the surface by means of aluminium tape, clips, springs or straps, the latter, on request, with grommets. Important point:: Make sure that the elements are making good contact everywhere on the heated surface. The screw joint method requires more space and more fixings than the methods mentioned earlier but the result will be very good if the installation is properly carried out. Importa Position the screws in such a way that the nt:: pressure is evenly distributed throughout the element surface. Large elements can be designed with holes for the screws. The pressu plate that is mounted on top of the elements must be stiff enough to distribute the pressur evenly throughout the surface. To help in distributing pressure and smoothing out any uneven spots, a layer of insulation may be put between plate and element.
The silicone elements are capable of being attached to the surface of a construction in a way that is right for that surface. It‐is extremely important that the elements should be in close contact with surfaces which dissipate heat. This is to make certain that the elements have a long service life. For cylinder‐shaped pipes, tanks, barrels and the like, it is recommended that you use the hook and tension spring method of mounting. This gives you elements that are easy to remove and that always fit tightly onto the surface. If you choose to fasten the elements permanently, it is recommended that you glue them down using 1‐ or 2‐component silicone adhesive. We would be happy to assist you with detailed instructions on how to apply silicone elements using different kinds of adhesive. We also offer to carry out gluing of silicone elements in our workshop. Gluing is a method of keeping the elements permanently fixed to the surface. It is relatively easy to use and ensures good heat transfer by conduction.
Importa - Always start with clean surfaces. This is nt: absolutely necessary when gluing. - All dirt must be removed by careful cleaning - The glue must be applied evenly. - The glue joint must be completely cured before it is subjected to any strain. - When gluing, always follow the manufacturer’s instructions.
Industrial heating – Silicone heaters 4 Product sheet
VärmeKabelTeknik
Technical construction The resistance wire is wound around a very thin fibreglass core. It is then laid out on a sheet of fibreglass‐rein‐forced silicone cloth and usually arranged in a symmetrical pattern. If desired, the spaces between the wire runs can be made smaller in some sections of the element in order to achieve a higher output in those areas. Next, a silicone cloth is put on top and the complete element is placed in a vacuum chamber, where all air is removed from it. Lastly, the element is vulcanized under pressure and a high temperature.
Technical data
Maximum surface power „Rule of thumb“
Dimensions:
From 10x10 mm (min) to 915 x 2800mm
0.75 W/cm²
In open air
Thickness:
1,5 mm (std) ‐ 0,5 mm (min).
1.5 W/cm²
Weight:
1,5 mm weighs 2,2 kg/m², 0,5 mm weihgs 0,65 kg/m².
Glued to metallic surface
2.3 W/cm²
Oper.temp:
Continuous operation ‐ max 250°C.
Clamped to metallic surface
Maximum resistance /cm²
31 Ω/cm²
Depending on the operating temperature Surface power see diagram 1.
Sheath temp. See Diagram 2 Voltage:
Max. 480 V.
Current:
Max. 30 Ampere
Diagram 1
Diagram 2
Special designs:
Build‐in thermostats Build‐in thermocouplers Waterproof element Different voltages Customer specified connection cables Extra thin constructions (0,5 mm) Unsymmetrical heat concentration Barrel heaters
VärmeKabelTeknik Barrel heaters
Industrial heating – Silicone heaters 5
The easy solution for heating and temperature maintenance of media in standard barrels (205 l)
These heaters are used, for example:
in the food industry for melting fats, honey, sugar products
in the chemical industry for keeping paint, glue, chemicals etc warm.
in the oil industry for transporting and storing frost sensitive oils and emulsions.
at airports for storing oils and de‐icing solvents
on building sites
Power output: 425 W/220V Weight: 0.9 kg SEMKO approved The barrel heater is supplied complete with a two‐metre connection cable, equipped with earth‐leakage circuit‐breaker.
Industrial heating – Silicone heaters 6 Temperature Control of Silicone Elements
As a rule, a silicone element requires some form of temperature control in order to ensure long element life and provide the desired temperature.
Because of the very small mass of a silicone element it will quickly come up in temperature, so control equipment with a relatively fast response is needed.
Where surface loads and temperatures are low and intervals between on and off long, electro‐ mechanic‐al thermostats of the bimetal type are often adequate for the purpose of limiting temperature.
Where surface loads and temperatures are higher, electronic thermostats are to be preferred.
If a silicone element is subjected to stress in the shape of continual cooling and heating‐up phases because of short intervals between on and off states, the life of the element will be significantly reduced. To avoid this, the best thing to do is apply the element power output proportionally or use a soft‐start regulator.
Thermostats, thermofuses and sensors of various types such as Pt‐100, thermocouples and thermistors, these can all be applied directly to the silicone elements, in accordance with customer specification.
Where you locate the sensors and thermostats is critical to the accuracy of the temperature control. Generally speaking, the greater the distance between sensor and heating element, the greater will be the variations in element temperature.
When heating a liquid held in a container, it is advisable to use a sensor mounted with pocket for temperature control, together with an overheat protection device mounted on the elements.
Consultancy and construction assignments Värmekabelteknik has the specialist knowledge and experience required for heating‐foil applications, including both silicone element and control device expertise. We can offer consultancy services and design, construction and delivery of complete installations.
VärmeKabelTeknik
VärmeKabelTeknik Control/Control cabinets
Industrial heating – Silicone heaters 7
We build control cabinets of all sizes according to customer specifications using components and enclosures made by well‐known suppliers.
All types of enclosure designs
• IP 20 – IP65
Alternative control devices:
• EX‐classified enclosures and components
• Electronic thermostat with NTC / PT‐100 sensor.
• Enclosure materials: plastic, metal, aluminium,
• Elektronic thermostat with temperature display • Process regulator with one to ten channels and PC communication
• For mounting on wall, floor or on foundation designed for ground installation.
• PC‐based thyristor‐control devices communicating remotely via mobile or fixed telephone (logging of current, temperature, wind and moisture, to name a few parameters).
• Cabinets controlled from a computer sub‐centre (DUC).
Alarm functions on cabinet front, alarm panels, pc network operation, dialling wireless alarm devices.
• Fuse blown/Circuit‐breaker tripped alarms • Earth‐leakage circuit‐breaker tripped alarms • Temperature alarm • Over‐current/Interruption alarm, and other alarms.
stainless steel
Industrial heating – Silicone heaters 8
VärmeKabelTeknik
Telephone: +46‐301‐418 50 – Email: info@vkts.se – Homepage: www.vkts.se
Industrihuset
Södra Hedensbyn 43
S‐430 64 HÄLLINGSJÖ
S‐931 91 SKELLEFTEÅ
Sweden
Sweden
Fax: +46‐301‐418 70
Fax: +46‐910‐881 33