Silicone Rubber Heaters

Flexible Heaters

Flexible Heaters, of which Silicone Rubber and Kapton are two types, were originally designed for the aerospace and defense industries. Common were such applications as maintaining constant temperatures in the instrumentation of aircraft, satellites, navigation, guidance and radar equipment. The versatility of this product has since been widely recognized as thousands of uses have been discovered. Flexible heaters are regularly specified because of their light weight, thin profile, low thermal mass and flexibility. The abilities to provide an infinite array of patterns and concentrations of heat are additional characteristics. Complex shapes, contours and three-dimensional patterns are possible. Many mounting methods are available for the application of Flexible Heaters. Computer generated specifications and state-of-the-art manufacturing technologies produce the most effective Flexible Heater performance possible, with typical OGDEN reliability.

Applications:

Antenna Deicing

Optical Equipment

Spacecraft

Farm Animal Feeders

Aircraft Air Intake

Laser Printers

Photocopy Equipment

Glue and Laminate Curing

Consumer Appliances

Hydraulic Equipment

Aerospace Composite Bonding

Battery Heating

Photography Developing

Gyroscopes

Floor Processing Equipment

Food Service Equipment

Vending Equipment

De-icing and Anti-icing Equipment

Outdoor Electrical and Electronic Enclosures

Oil Pumps and Reservoirs

Presses

Aircraft Galley Equipment

Electric Motor Dehumidifying

Heat Sealing

Medical, Laboratory and Veterinary Equipment

Dispensing Equipment

Automobiles and other Vehicles

Packaging Equipment

Freeze Protection for Drains in Refrigeration Equipment

Vacuum Chambers

Autoclaves

Resistance Element

The resistance element in Flexible Heaters is either wire wound or etched foil.

Wire Wound Element: A fine gauge resistance wire is spiralled around a fiberglass core. The element is placed in a specifically designed pattern and vulcanized to either a silicone rubber or neoprene substrate. Advantages versus etched foil elements are: Physical strength; flexibility; smaller production quantity; conforms well to small radius bends and larger possible sizes.

Etched Foil Element: The manufacturing process of etched foil elements is adapted from the production of printed circuit boards. A nickel resistance alloy foil is acid etched to the specific pattern, then vulcanized to the sheath material. Advantages versus wire wound are: Higher watt densities; greater area coverage of element over heater sheath; higher production quantities and complex heat distribution.

Silicone Rubber Heaters

Silicone Rubber Heaters are rugged, moisture and chemically resistant and are easily bonded or cemented to heat sinks or other parts to be heated. Temperatures from -80 to 390°F (-62 – 200°C) in a wide range of watt densities are regularly supplied. The thin profile transfers heat quickly because the actual resistance element is so close to the heated part. Silicone Rubber Heaters can be insulated with silicone sponge rubber bonded to one side. Another way to lower radiated and convected heat losses is to apply an aluminized foil surface to the heater back. Very little is added to the overall thickness. A common application of Silicone Rubber Heaters is Wrap Around Drum Heating.

Kapton Heaters

Kapton Heaters are especially thin and light weight, yet resistant to tearing and cuts. Kapton is an organic polymer that has high dielectric capabilities and tensile strength. Temperatures from -328 to 390°F (-200 to 200°C) are possible while providing a high resistance to many solvents, oils, radiation and fungus. Because of very low outgassing properties, Kapton heaters are suitable for use in high vacuum applications. Standard bonding methods can be applied. Being transparent adds to Kapton’s versatility.Other sheath materials such as Neoprene, Mica and Mylar are available.

Termination

Silicone leads for temperatures to 390°F (200°C) are most often supplied, but many other types are available. The leads are attached to the element within the transition area and covered with a patch of the same material as the sheath.

The entire lead transition assembly is then vulcanized to the heater sheath. Leads can be arranged to exit at about any point on the element sheath, corner, or from an external tab. Neoprene, silicone and Teflon leads along with SJ and HPN cord and plug sets can be supplied. Silicone Rubber leads are standard unless otherwise specified. Teflon leads are also available. 14, 16, 20 or 24 gauges are sized by requirement. Maximum lead length is 72″. Available with Patch and Strain Relief Tab.

Patch Lead patch can be placed along the heater edge at the following positions:
CW – Center of width
UW – Upper corner of width
LW – Lower corner of width
Standard patch dimensions vary by heater size and design.

Strain Relief Tab Standard tab dimensions: 2″ long x 2-1/2″ wide. Can be placed in CW, UW or LW position. Minimum width: 2-1/2″

2 Conductor SJ type 16/2 Cord with 2-3/4″ Round Termination Cap is often specified. Max temp is 140°F. NEMA1-15P Plug is available for 120 volt items. 3 Conductor SJ type 16/3 Cord with Round Termination Cap is also available. Ring terminal is attached to ground wire. Max temp is 140°F. NEMA1-15P Plug is available for 120 volt items.

Mounting Methods

Pressure Sensitive Adhesive (PSA) is a factory applied material for bonding Flexible Heaters to a flat, smooth surface. A peel-away protective backing allows simple field installation. The maximum element temperature for PSA use is 300°F (150°C) continuous, at no more than 5 watts per square inch. Heaters with PSA should be stored no more than 6 months before installation.Factory Vulcanizing provides excellent heat transfer from the heater element to the customer part. Strong, free of air gaps and with the longest possible heater life are advantages of Factory Vulcanizing.

For field applied adhesives, an RTV Room Temperature Vulcanizing Adhesive or Contact Cement are available. Consult Ogden.

Also available for Flexible Heaters are several mechanical field mounting devices such as hooks and laces, grommets and laces, spring loaded latches, snaps or velcro.

Thermostats and Sensors

Thermostats are typically integral to the heater, encapsulated in silicone rubber and mounted in a heated area. The position is determined based upon application considerations, prototyping and testing.

Thermostats separate from heater and ambient sensing thermostats in several temperature ranges are also available.

Thermocouples, RTD’s, thermistors and thermal fuses are normally mounted under a silicone rubber cap which is vulcanized to the heater sheath. The position can be anywhere on the heater surface.

Adjustable Thermostat Temperature Ranges

70 – 140°F
70 – 190°F
70 – 425°F

120/240V
120/240V
120/240V

1600W Maximum
1600W Maximum
1600W Maximum

Thermostat can be wired separately when rating is exceeded.

All items rated 125V/15A, 250V/10A.
Thermostat can be wired separately when rating is exceeded. Typically, the differential between the on and off position is 30°F. Tolerance: ± 5°F open ± 8°F closed Specify from the following values:

OPEN

55°F	40°F
(ambient sensing only)

160°F

130°F

170°F

140°F

80°F

50°F

180°F

150°F

100°F

70°F

190°F

160°F

110°F

80°F

200°F

170°F

120°F

90°F

250°F

220°F

130°F

100°F

300°F

270°F

140°F

110°F

392°F	365°F
(hi-limit only)

150°F

120°F

Thermostats and Sensors

	Surface Temperature versus Time for Silicone Rubber Heaters Illustrated is the surface temperature of a standard Silicone Rubber Heater, .055″ thick without insulation at several watt densities. The heater is suspended vertically in 70°F (20°C) still air.
	Maximum Watt Density Etched foil elements can be designed at higher watt densities based upon application considerations.

Specifications

Thickness of Optional Silicone Sponge Insulation: 1/8″, 1/4″, or 1/2″ Thickness of Optional Foil Backing: 0.005″ (0.13mm).

The area where leads are attached adds additional thickness depending upon gauge wire used and type. Dimension Tolerances: Less than 6″ (150mm); ± .03″ (± .8mm);
6 – 12″ (150mm – 305mm); ±.06″ (±1.5mm);
12 – 36″ (305mm – 915mm); ±.12″ (±3.5mm);
Over 36″ (915mm); ±1%
12″ leads are standard. Gauge of wire to be determined based on amperage or other considerations.Composite Bonding Processes and other applications may require special heat pattern or uniformity. Heat Mapping Certification is available as an option. Underwriter’s Laboratory and CSA recognition or listing apply to most configurations. As an option, we can certify to CE.

Many applications require special designs and considerations. We will provide assistance to develop a flexible heater for a specific application.