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HEATING WIRES & DEVICES |
APPLICATIONS SPECIFICATIONS SIZE TABLE WHAT IS TWS? ADVANTAGES OF TWS ORDERING INFORMATION
ADVANTAGES APPLICATIONS SPECIAL EQUIPMENT WIRES QUALITY FEATURES CAUTION ADVANTAGES OF TWS LIST OF MIL-W SPEC SHEETS CONDUCTOR SIZE TABLE INSULATED WIRE SIZES COAXIAL CABLES PER MIL-C-17 TABLE OF COAXIAL CABLES MULTI-CORE CABLES HIGH VOLTAGE WIRES & CABLES HVCR SELECTION GUIDELINES HVCR QUALITY ASSURANCE HVCR SIZE TABLE HEATING WIRES WIRES FOR FLOOR HEATING
QUESTIONNAIRE FOR HVCR
PROPERTIES OF PTFE |
Poly Tetra Fluoro Ethylene (PTFE) is a plastic which is flexible up to -200°C and stable up to 260°C. These features have been utilised to develop safe, efficient and long-life PTFE insulated heaters. Such heaters find applications in 1. Flexible car seats, pads, carpet or blanket heating.CONSTRUCTION Three main parts of heating wires and devices are 1. Heating resistance wire capable of long-life stability at the required temperature. These are single or multi-strand, or helically wound 1, 2, 3 strands (on glass-fibre cord) of plated/unplated Copper, Copper alloy, Stainless Steel or resistance alloy.PRECAUTIONS The maximum operating temperature of PTFE related systems are limited to 260°C (total maximum spot temperature, i.e. temperature rise plus ambient). Although PTFE is known to withstand 380°C for short durations (without mechanical stress), the transition temperature is only around 325°C. Therefore, suitable protection must be provided to prevent accidental increase beyond 260°C. This protection is very critical for liquid heating systems which generally operate at high heat fluex densities. Such systems must never be allowed to run dry (out of liquid). Any spot of the heating element, if exposed, will rise in temperature towards self-destruction, electrical hazard and fire. Explosion may follow. Alternate built-in protection is to provide a longer length element with low watts per linear metre so that the spot temperature even under dry condition does not rise beyond 260°C. The cost will be higher for such systems. TYPICAL PRODUCT FORMS a) Round, single and multi-strand with desired RTI of PTFE. These are simplest and most widely used. The slight oval, flat strip or twin parallel-laid constructions offer better heat transfer.TECHNICAL CHARACTERISTICS 1. Ohmic value from 0.05 ohm/metre to 500 ohms/metre.SPECIAL FEATURES
Following is a list of standard Heating Elements for use at 230 V AC RMS. The typical product form consists of round Heating Wires with Stainless Steel Braid Shield and PTFE jacket with final OD 1.8 mm to 2.2 mm. Conductor used for heating element is multi-strand (dia 0.25 - 0.68 mm). For Free Design Service, Contact: mukul@druflon.com; druflon@gmail.com; nkrishna@druflon.com Teflon ® is a DuPont Trade Mark |