Temperature Control & Sensing Options
Air Heaters With Temperature Sensors
Process Sensors - A thermocouple or RTD sensor probe is inserted into a thermowell in the heater to measure duct air outlet temperature. Type J and Type K thermocouples and Pt 100 Ω DIN Curve RTD sensors are the most common used. Standard sensor lead length is 72” (1825mm). Specify sensor type and lead length when ordering.
High Limit Sensors - A thermocouple or RTD sensor probe is fed through the mounting flange and clamped directly to a heater element. This allows for early detection of element over temperature conditions that may shorten heater life. An alternative is to insert the high limit sensor into a thermowell that is clamped or welded to the heater element sheath. This facilitates easy sensor replacement, but at the expense of a slower sensor response time. Standard lead length is 72” (1825mm). When ordering, specify sensor type, sensor mounting style and lead length.
Industrial Air Heaters With Bulb & Capillary Thermostats
Thermostats - Single pole (SPST) and double pole (DPST) available. Optional knob & bezel.
| Description |
Maximum Voltage |
Maximum Amperage |
Bulb Length |
Bulb Diameter |
Capillary Length |
| 0-100°F SPST |
240V |
20 A |
3.3" |
.24" |
36" |
| 85-230°F SPST |
240V |
20 A |
3.3" |
.24" |
36" |
| 120-570°F SPST |
240V |
20 A |
3.5" |
.20" |
36" |
| 0-100°F DPST |
480V |
10 A / pole at 480V
30 A / pole at 240V |
4.5" |
.375" |
84" |
| 60-250°F DPST |
480V |
4.5" |
.375" |
60" |
| 100-550°F DPST |
480V |
4.5" |
.375" |
60" |
Process Air Heaters With Temperature Control Panels
Durex Industries electrical temperature control panels meet a wide variety of industrial requirements by providing an extensive line of standard and custom engineered solutions. All temperature control panels are fully pre-wired and tested at the factory and come with a set of drawings including schematics and installation and maintenance manuals. Standard temperature control panels include NEMA 12 enclosure, main power disconnect, process temperature controller, pilot lights, panel labels, primary and secondary fusing, and ventilation fan /filter (if required). Other options available.
Construction Options
Custom Voltage and Power Rating - A large variety of standard high-temperature and medium temperature process air heater designs are available. However, custom volts, watts and watt density designs are available upon request.
Duct Configuration and Plate Flanges - In addition to the standard duct heater designs, Durex will custom design and fabricate purpose-built duct heaters to fit virtually any duct size and mounting flange requirements. Standard mounting flanges are carbon steel, however, 304 stainless steel and 316 stainless steel are readily available alternatives. Support rods, element support spacers and insulation collar are all of stainless steel construction standard.
Replaceable Heater Elements - Durex standard design air heaters use seal-welded heater elements. Optional replaceable heater elements can be specified with retaining clips or gas-tight compression fittings. Retaining clips keep elements in place and allow easy replacement in minimal pressure applications. Compression fittings offer field replacement, while still providing a gas-tight seal. Contact Durex for assistance in specifying replaceable elements.
Seal Options
Silicone Conformal Coating – On standard heaters, this seal provides general moisture / contamination protection to 220°F (105°C). However, it is porous and will allow moisture penetration over time. Not recommended for storage or use in high humidity environments.
Silicone RTV – Offers improved moisture and contamination protection to 400°F (200°C). However, it is also porous and will allow moisture ingress over time.
Epoxy Seal – Offers the best moisture and contamination protection of these seal choices. Rated for 450°F (230°C), this seal has low porosity and is recommended for higher temperature applications, high moisture environments and where long term storage is foreseen.
They are typically used in forced air ducts to heat the airflow for processing applications, and they can also be found in:
- Industrial Drying & Curing
- Heat Treating
- Reheating & Dehumidifying
- Autoclaves
- Convection furnaces
- Core & Refractories Drying
- Load Banks
