Heating where it is needed

4 5

Flexible foil heaters provide precise, dependable and immediate heat transfer, exactly where it is needed. There are a vast number of existing and possible applications throughout various industries. At Calesco’s innovation center, highly qualified and experienced engineers continuously take on the challenge of new applications and materials. The results have allowed for customized heating solutions that meet the demands of our customers in every industry.

Foil heating applications

MEDTECH AND HEALTHCARE

AEROSPACE AND MILITARY

COMFORT

INDUSTRY

AUTOMOTIVE AND TRANSPORTATION

SPECIAL

° Surgical tables/beds

° Sterilization equipment

° Laboratory research equipment

° Autoclaves

° DNA Analysis

° Respirators

° Incubators

° Radiators

° Floor heating

° Waterbed heating

° Heat pumps

° Heating panels

° Mirror heater/demister

° Side rear view mirror heaters

° Coupler for trains

° Hand grip heaters for 4WD, ATV and snow mobiles

° Heating for tram lines

° Coupé heating solutions for vehicles and public transportation

° Green technology heating solutions

° Integrated heating for boots

° Exotic plant heating

° Aerospace equipment

° Satellites

° Military equipment

° Mock targets

° Batteries heaters

FOOD AND BEVERAGE

° Heating cabinets

° Cooking equipment

° Espresso makers (mug warmers)

° Professional kitchen applications

° Defrosting

° Packing, strapping and sealing equipment

° Photographic equipment

° Chainsaws

° Heating shields

° Tooling equipment

SURVEILLANCE AND ELECTRONICS

° Sensor cameras

° Electronic monitoring

° Control panel heaters

° Heating elements for activation of components or LCD circuits

° Batteries

° Sensors

° Lens heaters

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At Calesco, we develop new products and solutions in close cooperation with our customers,

transforming a customer request into a working solution. The process is successfully achieved

from our broad experience, advanced design tools and efficient production capabilities.

The idea takes shape at the drawing board

Etching the circuitAutomated component placement and soldering station

Component assembly

Performance testingFinal testing

Automated silk screen production

Printing a circuit6 meter vacuum tables

Inspection and verification

Measuring and technical documentation

Laser cutting

From idea to solution

Long term testing

Climate chamber testing

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POLYIMIDE

Thin and semitransparent with excel-lent dielectric strength. Resistant to chemicals.

° Military and aerospace

° Medical diagnostic instrument

° LCD displays

° Photographic equipment

– PTC PRINTED POLYMER

Self-regulating, robust and corrosion- resistant with PTC characteristics.

° Rear view mirrors

° Floor heating

° Waterbed heaters

° Low temperature applications

° De-icing

PEN HEATERS

High mechanical strength and chemical resistant.

° Electronic devices

° Radiators

° High power standard element

MICA

High power density. Fast warm up and high working temperatures.

° Food service appliances

° Semiconductor industry

° Laboratory equipment

POLYESTER– ETCHED FOIL

Superior heat transfer and uniform heat output. Fast warm up with long life cycle.

° Mirror heaters

° De-icing equipment

° Hand grip heaters

° Rear view mirrors

SILICONE

Excellent temperature properties. Can be vulcanized to metal parts

° Food service equipment

° Respirators

° Ultrasonic cleaners

° Photocopy machines

PVC

Very flexible, water proof and acid resistant with high mechanical strength.

° Waterbed heaters

° Water heaters

° Military equipment

° Battery heaters

FRTP

Stiff, extremely durable, water resistant.

° Radiator panels° Floor heating° Heater for rough conditions

– PRINTED POLYMER

Low power, constant wattage with a large span of resistivity. Insensitive to small damages.

° High voltage, small area applications° Water bed heaters° IR targets° Floor heating

Insulation materialsFoil heating basicsA foil heating element is built up with one or more

layers of insulation and a heat circuit. Among the

insulating materials used are PVC, polyester, silicone

rubber and micanite. The circuit material may be a

resistance heating alloy, such as copper, brass or alu-

minium. We can also provide a carbon or silver based

circuit. The operating voltages may be from 1 or 2 V

up to 700 V AC/DC. Element temperatures range up to

600°C. Several circuits may be arranged on the same

heater. A foil element provides even heat distribution over

the entire surface. It is also possible to divide the

heater into different heat zones, and power densities.

Foil elements can also be designed to be EMF free.

FLEXIBLEMULTIPLE CIRCUITSCUSTOMIZED

MULTIPLE VOLTAGESPRECISE SENSOR LOCATIONEVEN TEMPERATURES

Foil heating advantages

• Customized shapes

• Multiple temperature zones

• Flexibility

• Thin

• Light weight

• Simple assembly

• Quick heating

• Efficient heat transmission

• Low energy consumption

• High quality

Insulation material

Insulation material

Circuit

Foil heating elements are designed accord-ing to customer needs and requirements.

Elements can be designed with varying output to compensate for heat loss at the edges.

Elements can generate different heat levels on the same surface area.

Sensors can be added in any location on the same level as the heating circuit.

Elements can be attached to products with many different shapes.

An element can combine 220V/12V to standardize one element for different voltage products.

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Technical information

0 10 20 30 40 Sec

°C

140

120

100

80

60

40

20

0

°C

140

120

100

80

60

40

20

0

Temperature rise

0.60 W/cm2 0.50 W/cm2

0.40 W/cm2

0.30 W/cm2

0.25 W/cm2

0.20 W/cm2

0.15 W/cm2

0.10 W/cm2

0.05 W/cm2

Temperature rise

Temperature curves and required effect

The following information will assist in the design of

elements and rough calculation of data. Optimum effect

and temperature conditions for specific applications are

usually determined experimentally.

The diagram shows temperature rise as a function of time

for certain applications and various types of elements with

different surface ratings. Surface rating is defined as the

total power divided by the effective area of one side of the

element. The figures refer to elements suspended horizon-

tally in free air.

Foil mounted on alu plate, 215x155x5 mm with adhesive

Foil mounted between two alu plates, 185x140x5 mm

Element type PVC Polyester Polyimide Silicone Micanite FRTP

Max. element temp.(depending on application)

70°C 105°C 200°C 230°C 400°C 100°C

Min. element temp. -40°C -60°C -60°C -50°C -50°C -40°C

High voltage resistanceat 20°C as per ASTM KV/mm

15 220 200 17 32 5

Thermal conductivityat 100°C W/(m x K)

0.17/70°C 0.16 0.17 0.24 0.30 0.36

Moisture absorption as per ASTM D-570-63 (24 h immersion at 23°C

0.2% 0.8% 2.9% 0.1% 1.0% 0,025%

Moisture resistant as per IEC 335-1 sect. 15-16

yes yes yes yes yes yes

Waterproof as per IEC 335-1 sect. 15-16

yes yes - yes - yes

Constant of dielectricity at 25°C 50Hz

5-9 3.3 3.5 2.9-3.6 4-5.5 3

Constant of dielectricity at 150°C 50Hz

- 3.7 3.1 - 6.2 -

UV radiation resistance limited limited limited good very good limited

Solvent resistance very limited limited limited limited limited limited

Bending radius, min. 20 mm 1 mm 1 mm 10 mm - 400 mm

Max. element width 900 mm 900 mm 600 mm 600 mm 600 mm 600 mm

Min. thickness 1.2 mm 0.15 mm 0.15 mm 0.8 mm 0.5 mm 1.5 mm

Resistance 0.01 ohm/cm² to 6000 ohms/cm²

Resistance tolerance As standard, ±10% of nominal.

Tolerance down to ±2% avaliable to special order.

Rated voltage Up to 500 V AC/DC single or 3-phase.

Foil heater mounted in free air

°C

340

320

300

280

260

240

220

200

180

160

140

120

100

80

60

40

20

0

°C

340

320

300

280

260

240

220

200

180

160

140

120

100

80

60

40

20

00 2 4 6 8 10 min

Temperature rise

5.0 W/cm2 4.0 W/cm2 3.5 W/cm2

3.0 W/cm2

2.5 W/cm2

2.0 W/cm2

1.5 W/cm2

1.0 W/cm20.75 W/cm2

0.5 W/cm2

0.3 W/cm2

0.2 W/cm2

0.1 W/cm2

0.05 W/cm2

1.0 W/cm2

0.5 W/cm2

Foil heater mounted on heat sink

12 13

Temperature controlIn conjunction with Calesco foil heating elements it is

usually necessary to arrange some form of control to

ensure that the desired temperature is maintained. A foil

element has very small mass and is quickly heated.

Accurate temperature control is therefore needed. This

can be achieved with electromechanical thermostats of

bimetallic type when temperatures and surface ratings

are low, while electronic thermostats are preferred when

temperatures and surface loads are high.

We can fit thermostats, temperature fuses and sensors

of thermo element type, thermistors and resistance

sensors directly to elements in accordance with

customer specifications. This helps to ensure

reliable control. The placing of components

can vary. It is often preferable to minimize ele-

ment temperature and accept a deviation from

the ideal working temperature. Final decision on thermo-

stat temperature settings and location can often be made

only after practical tests.

Calculation of power

(cm2)

5000

4000

3000

2000

1000

0

Amax (single-sided)

0 1 2 3 II(mA)

Leakage currents for foil heaters at 220√ 1.15 V for various insulation materials and thicknesses

0.380 mm 0.190 mm

0.300 mm

0.125 mm

0.200 mm

0.075 mm

0.050 mm

0.025 mm

The following formula can be used to determine the required rating

P to heat a given material approximately.

Specification of heat and density of common materials:

Material Spec. heat Ws/(g °C)

Densityg/cm3

Aluminium 0.90 2.7

Copper 0.39 8.9

Stainless Steel 0.50 8.0

Iron 0.46 7.8

Water 4.18 1.0

Electrical insulation and calculating leakage currentWhen a foil element is fitted on a metal surface,

leakage current must be taken into account.

In industrial and low-voltage (<48V ~) applications

there are no limitations regarding leakage current,

while strict limitations apply to household applianc-

es. The basic standard for heating appliances is laid

down in the test rules IEC 6605, on which various

national standards (SEMKO, NEMKO, DEMKO, VDE

etc.) are based.

The maximum level of leakage current for Class I

(earthed) appliances is 0.75 mA/kW while for Class

II (double insulated) appliances it is 0.25 mA/kW.

Medical appliances are subject to special leakage

current restrictions as per IEC 601.

Weight of material (g) x spec. heat ( Ws/(g °C)) x temp. rise (°C)

Time sec.P = W

PTC Heating ElementsThe Calesco self-limiting heating foil with PTC effect (Posi-

tive Temperature Coefficient) is based on a special carbon

filled polymer material that increases resistance with tem-

perature and hence automatically limits the power gener-

ated by the heater.

The resistance increases gradually from room temperature

up to 80°C by about 5–6 times. When 80°C is reached the

power decreases 80–85% from the initial value. The benefit

with this type of PTC heater, is the decreased risk for over-

heating, compared with a traditional resistive metal heating

element. Even though metals also increase resistance with

temperature, the effect is not as dramatic as for the PTC/

polymer element.

The nature of the polymer PTC heaters make them the

most suitable for low temperature applications with operat-

ing temperature below 30°C.

Due to the variable nature of the resistance in the element,

it is rather difficult to predict the exact heating power. It

depends highly on the heat dissipation of the heat sink it is

attached to.

Temperature °C

PTC

Effe

ct r

elat

ed t

o R

esis

tanc

e at

20°

C

Temperature °C

Pow

er r

elat

ed t

o P

ower

at

20°C 1,6

1,4

1,2

1

0,8

0,6

0,4

0,2

0-40 -20 0 20 40 60 80 100

8

7

6

5

4

3

2

1

0-40 -20 0 20 40 60 80 100

Polyester Silicone

Polyimide Micanite

14

Backer BHV AB

div. Calesco

Västra Åvägen 11

SE-734 51 Kolbäck

Sweden

tel: +46 220 453 00

www.calescofoil.se

CALESCO offers the widest product range of all flexible foil heater

manufacturers in the world.

Our mission is to find an optimal, cost efficient solution for every customer

with a need for heating elements. With over 40 years of experience from a

diversity of market segments and applications have given us the compe-

tence not only to supply a heating element, but to provide a total heating

solution.

With production in Sweden, Poland and China and a sales office/ware-

house in the US, CALESCO combines excellent quality with global sourc-

ing for cost competitiveness and efficient logistic solutions.

CALESCO is part of the Backer Group within NIBE Element, one of three

business areas of NIBE Industrier, listed on the Stockholm Stock

Exchange since 1997.

Head Office: Backer BHV AB · Fabriksgatan 11 · SE-280 10 Sösdala · Sweden · tel: +46 451 66100 · www.backer.se

Methods of assembly

Typical methods:· Adhesive

· Tensioned elements

· Threaded fixings

· Shrink tubes

· Vulcanizing (carried out by CALESCO)

Assembly Advice

AdhesiveA general rule is that successful assembly with adhesive requires a flat surface.

It takes at least 24 hours for the adhesive to cure properly.

Surface Preparation Remarks

Metals and glass Clean thoroughly

For best results, working temperature should be over 15°C.Ensure exclusion of air pockets. pressing from center outwards.

Plastic Clean thoroughly

As above. Note that plastics containing plasticizer i.e. certain thermoplastics, are unsuitable for adhesive assembly.

Tensioned elementsSpring or clamp connections used to secure the heating element with an even pressure

onto a surface.

Threaded fixingsThe clamping screws or bolts must be arranged to give an even pressure over the whole

area of the element. The position of screw holes must be taken into account in the design

of the element. The clamping plate must be rigid, so that pressure is evenly distributed

over the whole area. An insulating layer may be used between the plate and the element to

equalize pressure.

Shrink tubesElements may be fitted to pipes with shrink tubes. The right gauge and size needs to be

determined.

VulcanizingElements could be attached to various metal surfaces in different shapes.

Your partner for precise heating

Backer BHV AB, div Calesco, Västra Åvägen 11, SE-730 40 Kolbäck, SWEDEN, Tel: +46 220 453 00, www.calescofoil.se