Silicone Rubber Heaters

Exit together, centered on heater width

Exit together, to one side of the heater width

Exit together, to one side of the heater width

Exit opposite ends, centered on heater width

Exit opposite ends, to one side of the heater width

Exit together, centered on heater length

Exit together, to one side of the heater length

Exit together, to one side of the heater length

Exit opposite ends, on the same side of the heater length

Exit together from the center of the heater surface

Exit together the edge of a round heater

Exit together at a corner

Lead exit specified by customer. Please include drawing when submitting to Tempco.

Tempco’s standard leads are 10″ long, Teflon® insulated, flexible, stranded, plated copper wire. Stripped: 1/4″ UL1180 rated 300V 200°C UL1199 rated 600V 200°C The lead connections are insulated with vulcanized silicone rubber, which also acts as a strain relief.

For portable heaters, a two-conductor neoprene cordset can be vulcanized to the heater in any desired length.

A two-conductor neoprene cord and plug set can be vulcanized to the heater. Standard Length: 6 ft. (1.83 M), 7 ft. (2.13M), or custom length as specified. Supplied with standard straight blade ungrounded plug, or grounded plug. 120Vac only. 2-Pole 2 wire non-grounding (NEMA 1-15P) 2-Pole 3 wire grounding (NEMA 5-15P)

For industrial applications, SJO heavy duty power cords can be attached to the heaters in any desired length.

SJO heavy duty power cord and plug set can be attached to the heaters. Standard Length: 6 ft. (1.83 M), or custom length as specified. Supplied with standard straight blade ungrounded plug, or grounded plug. 120Vac only. (For 240Vac see page 15-15 for optional plugs) 2-Pole 2 wire non-grounding (NEMA 1-15P) 2-Pole 3 wire grounding (NEMA 5-1

Ensures a moisture seal on the heater. Due to the similarity in material, the heater will fuse to the leads during the vulcanization process. Silicone rubber leads are more flexible, but are not as abrasion resistant as Teflon® leads.

Crimp Connectors: insulated or non-insulated Ring Terminal Spade Terminal 1/4″ Female Straight Disconnect 1/4″ Female Right-Angle Disconnect Miniature Connectors: example – Molex

Standard 120 or 240 Vac – straight blade Twist locking plugs, 120 to 480 Vac Specify NEMA or manufacturer’s part number

Used to encase lead exit and optional snap action thermostat. Shown with SJO cord rated -50°C to 105°C.

Various materials can be put over Teflon® or Silicone Rubber leads to provide mechanical or abrasion protection. The leads exit the heater as a single unit. Silicone Rubber/Fiberglass Sleeving (356°F/180°C) Heat Shrink Sleeving

For ease of attachment, specify PSA. Installation is simple: just peel off the protective liner and apply. It will adhere to most clean smooth surfaces. Care must be taken when installing to attain a smooth, consistent, uniform bond to achieve maximum results.

Maximum Temperature:

Continuous – 300°F (149°C)

Intermittent – 500°F (260°C)

Recommended Watt Density: Under 5 W/in2 (0.78 W/cm2)

PSA Plus A layer of aluminum foil is vulcanized to the back of the heater for added heat dissipation prior to the application of PSA.

Flexible heaters can be factory vulcanized to bare or anodized aluminum, Stainless Steel, Marble, or other hard surfaces for permanent attachment and excellent heat transfer. The uncured silicone rubber heater is placed on the metal part and placed in the vacuum oven where the heater vulcanizes and adheres to the part in one operation. This procedure forms an extremely strong permanent bond with most metals due to the fact that the silicone rubber flows into and fills the micro structure in the surface of the metal. The metal part can be manufactured by Tempco or supplied by the customer. Consult Tempco for other materials including granite.

A flexible magnetic material can be attached to the back of a silicone rubber flexible heater. Will adhere to many varieties of steel. Ideal for those situations were you need to “Slap On” some heat! Specify when requesting a quote.

Maximum Temperature: 200°F / 93°C

Maximum Watt Density: 1 W/in2 (0.16 W/cm2)

Maximum Width: 24″ (610 mm)

For a field applied permanent bond, a room temperature and ambient humidity curing silicone rubber adhesive is recommended. Tempco offers two types that will retain physical and electrical properties up to 500°F (260°C). When using RTV adhesive, cover the heater completely with a thin layer of RTV, position the heater in place, and use a small roller to remove air bubbles, which could cause hot spots and lead to premature failure of the heater.

Mechanical fasteners are available for applications where flexible heaters must be detachable from cylindrical parts.

Mechanical fasteners are available for applications where flexible heaters must be detachable from cylindrical parts.

Mechanical fasteners are available for applications where flexible heaters must be detachable from cylindrical parts.

Mechanical fasteners are available for applications where flexible heaters must be detachable from cylindrical parts.

Mechanical fasteners are available for applications where flexible heaters must be detachable from cylindrical parts.

Mechanical fasteners are available for applications where flexible heaters must be detachable from cylindrical parts.

Mechanical fasteners are available for applications where flexible heaters must be detachable from cylindrical parts.

Flexible heaters may be applied by clamping or compression between two rigid materials. The plate surfaces must be ground reasonably smooth. Care must be taken not to damage the heater or pierce the insulation. Mill out an area or cutout in the top plate for the added thickness of the lead exit area. Recommended Maximum Pressure: 40 PSI

Mechanical fasteners are available for applicationsTempco has developed the techniques necessary to permanently mount silicone rubber heaters to the outside diameters of pipes and medium size vessels. This technique is particularly useful for heated drums and air or gas heating.

Minimum Diameter: 0.5″ (12.7 mm)

Maximum Diameter: 6″ (152.4 mm)

Maximum Length: 20″ (508.0 mm) where flexible heaters must be detachable from cylindrical parts.

Dimensional silicone rubber heaters can be vulcanized to fit a shaped outline. This technique is particularly useful for wrapping Silicone Rubber heaters around pipes or small vessels. Custom tooling or special forms may be required.

Tempco can incorporate common Type J or K thermocouples almost anywhere on the heater surface. Other thermocouple types can also be used. Standard thermocouple temperature ranges apply. Specify when ordering. See Temperature Sensors for optional plugs.

The RTDs (2- or 3-wire) used are platinum thin film 100 ohm @ 100°C. The standard curve is 0.00385 TCR / DIN432760. Other common RTDs such as 1000 ohm can also be used. Specify when ordering. The RTD’s resistance increases with a rise in temperature and is considered the most accurate and stable sensor.

Thermistors are also a resistive-based temperature sensor. They do not generally respond in a linear style and are used in a limited temperature range or at a specific single temperature. Small bead style thermistors can be mounted directly on the heater. The thermistor’s response is generally designed directly into the customer’s electronic control system. Therefore if a thermistor is required, specify manufacturer, specific model number, type and specifications when requesting a quote. Consult Tempco for more information.

A temperature sensor is not needed for this heater.

Quick cutout on rise to temperature. The contacts will open on rise when the temperature increases to the snap point of the calibrated bimetal disc.

Setpoint (opens): available from 50 to 450°F in 10°F increments (most thermostats close 20 to 30°F below setpoint)

Electrical Ratings: 125 Vac, 15 Amp, 1875W, 250 Vac, 10 Amp, 2500W

Minimum Heater Width: 1.312″

Adjustable thermostats allow the user to dial-in a specific temperature and attain a desired result. The thermostat is enclosed in a molded silicone rubber housing and permanently attached to the heater. The adjustment shaft extends through a pre-formed hole. A high temperature knob is included.

Amps: 12.5A @ 125V, 6.5 A @ 250V

Watts: 1500W @ 120V, 1560W @ 240V

Adjustment Ranges Available: 50 to 425°F (10 to 218°C) 90 to 140°F (32 to 60°C) 100 to 190°F (38 to 88°C) 70 to 190°F (21 to 88°C) 50 to 160°F (10 to 71°C) 70 to 140°F (21 to 60°C)

Minimum Heater Width: 1.75″ (44.5 mm)

A High Limit with a manual reset push button can also be designed in. Specify when requesting a quote. NOTE: See page 13-83 for stock temperature ratings

Sustained response, and a slow cutout at the trip point. The creep action thermostat has a slow make/slow break action around setpoint.

Setpoint (opens): available in a limited selection from 50 to 300°F in 10°F increments. Consult Tempco.

Electrical Ratings: 120 Vac, 12 Amp, 1440W, 240 Vac, 6 Amp, 1440W

Thermal fuses / cutoffs are used as high limit protection devices to guard the object being heated from dangerous temperatures in the event of a primary control device failure. The thermal fuse can be mounted using various methods depending on other options. If the heater does not have a thermostat, the thermal fuse would be mounted under the lead exit patch. If used in conjunction with a thermostat, it could be mounted under the thermostat cover.

Some applications may require the heater to be grounded. Due to the fact that the heater sheath is non-conductive, this can only be done artificially. A second layer of insulating material and a conductive grid can be added to the heater. A ground wire is attached to the grid. A less expensive alternative for setting up a ground wire, especially for the required ground lead of a cordset, is to have a “flying ground lead” (6″ long, green) exit the lead patch for attaching to the metal load surface, effectively grounding the process.

Due to the flexibility in circuit design for flexible heaters, heating circuits can be designed to accommodate dual voltage. On dual voltage heaters, three leads, including a common in a different color, are provided for wiring the heater in series for the higher voltage and parallel for the lower voltage. 120/240 Vac or 240/480 Vac can be specified.

Heaters can be designed with internal three-phase delta wiring. Three phase WYE wiring is also possible but less preferable in most cases. All 3-phase heaters will have three power leads coming out of the heater. Three phase heaters are typically larger heaters used in high current applications.

The alloy used for this heater’s resistance wire has a high positive temperature coefficient of resistance that allows the heater to reduce power as temperature increases. This self-regulating feature is ideal for many low temperature applications. This feature can also be beneficial when a fast start-up time is required before the heater power levels off to normal operating temperature. See Chart for Ratio of Hot to Cold Resistance of the Heater wire at various wire temperatures.

To increase heater efficiency, silicone sponge rubber insulation can be bonded to the top side of the heater. Available thicknesses are 1/16″, 1/8″, 1/4″, 3/8″ or 1/2″. Thermal Conductive Sponge can be use to transfer heat evenly to various surfaces. Available in 1/8″ thickness.

Aluminum foil can be added to the back of the heater to help dissipate the heat between element runs and eliminate hot spots. Due to the foil, higher watt densities and better temperature uniformity can be attained. The foil would be applied to the back of the heater, on the mounting surface.

In order to compensate for heating losses around the edges or mounting holes, the heating circuit can be designed in a distributed wattage pattern. More wattage can be added to the high loss areas to compensate for the higher losses.

An unheated lead exit tab can be added to the heater for a variety of reasons such as maintaining a rectangular heater with no cold sections or when used in a compression application to remove the lead exit area from between the plates. (Standard 2″ x 2″)

Multiple circuit areas can be zoned to compensate for various heating effects desired. In the picture above there are three zones with separate leads (A, B, and C).

Holes and cutouts in the surface of a silicone rubber heater can generally be placed anywhere in the heater assembly. Holes and cutouts can be used to allow space for bolts, nuts, temperature sensors, brackets, etc. For most holes and cutouts, a detailed drawing will be required for quoting or ordering.