Screw Plug Heaters are constructed by brazing or welding elements into a hex pipe thread. These are intended for direct immersion into fluids and gases. The heater is to be installed via a threaded port in the tank or vessel. Screw plug heaters are available in a variety of pipe thread sizes and materials. The heating elements are offered in a number of materials suited to a variety of fluid heating applications. Terminal housings are available for indoor, outdoor (weatherproof NEMA 4) and hazardous (NEMA 7) environments. Many options are available including thermostats, high limit and process thermocouples or RTD sensors. Since we are a made to order company, we can offer a large selection of sizes and configurations which are not listed below.
Standard Plug Sizes & Materials
| NPT Sizes
British Sizes Materials |
1″, 1 1/4″, 1 1/2″, 2″, 2 1/2″
1″, 1 1/4″, 1 1/2″, 2″, 2 1/2″ Brass, Steel, Stainless Steel |
Common Sheath Materials
| Copper
Steel Stainless Steel Incoloy 800 ® Inconel 600 ® |
Potable Water
Fuel Oils, Hydraulic Oils De-Ionized, R-O, Process Water, Mild Acids Water, Mild Alkaline Solutions, Air and Gases Water, Very Alkaline Solutions, High Temperature Air and Gases |
Built in Thermostat Options
| Power Ratings | Up to 240 volts, 25-amp single pole, single throw (SPST)
Up to 240 volts, 25-amp double pole, single throw (DPST) Up to 600 volts, 15-amp triple pole, single throw (TPST) |
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| Temperature Ratings | 0 – 100° F 50 – 250° F 160 – 540° F 320 – 700° F |
Built In Sensor Options
| Sensors | “K” calibration thermocouple for high limit sheath protection and fluid sensing and temperature control.
“J” calibration thermocouple for high limit sheath protection and fluid sensing and temperature control. 100 Ohm RTD Sesnor for fluid sensing and temperature control. |
Terminal Housings and Constructions
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1″ NPT Screw Plug Immersion Heaters |
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General Purpose HousingsNo Thermostat |
General Purpose HousingsBuilt In Thermostat |
NEMA 4/NEMA 7 HousingsNo Thermostat |
NEMA 4/NEMA 7 HousingsBuilt In Thermostat SPST |
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1 1/4″ Screw Plug Immersion Heaters |
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General Purpose HousingsNo Thermostat Single Element Design |
General Purpose HousingsBuilt In Thermostat Dual Element Design |
NEMA 4/NEMA 7 HousingsNo Thermostat |
NEMA 4/NEMA 7 HousingsBuilt In Thermostat SPST |
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2″ Screw Plug Immersion Heaters (2 Elements, Single Phase) |
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General Purpose HousingsNo Thermostat |
General Purpose HousingsBuilt In Thermostat |
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NEMA 4/NEMA 7 HousingsNo Thermostat |
NEMA 4/NEMA 7 HousingsBuilt In Thermostat SPST |
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2″ Screw Plug Immersion Heaters (3 Elements, Single or Three Phase) |
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General Purpose HousingsNo Thermostat |
General Purpose HousingsNo Thermostat |
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NEMA 4/NEMA 7 HousingsNo Thermostat |
NEMA 4/NEMA 7 HousingsBuilt In Thermostat SPST |
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2 1/2″ Screw Plug Immersion Heaters (3 Elements, Single or Three Phase) |
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General Purpose HousingsNo Thermostat |
General Purpose HousingsBuilt In Thermostat |
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NEMA 4/NEMA 7 HousingsNo Thermostat |
NEMA 4/NEMA 7 HousingsBuilt In Thermostat SPST |
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NEMA 4/NEMA 7 HousingsBuilt In Thermostat 480/600 VAC TPST |
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General Purpose Housings
General Purpose Housings
NEMA 4/NEMA 7 Housings
NEMA 4/NEMA 7 Housings
General Purpose Housings
General Purpose Housings
NEMA 4/NEMA 7 Housings
NEMA 4/NEMA 7 Housings
General Purpose Housings
General Purpose Housings
NEMA 4/NEMA 7 Housings
NEMA 4/NEMA 7 Housings
General Purpose Housings
General Purpose Housings
NEMA 4/NEMA 7 Housings
NEMA 4/NEMA 7 Housings
General Purpose Housings
General Purpose Housings
NEMA 4/NEMA 7 Housings
NEMA 4/NEMA 7 Housings
NEMA 4/NEMA 7 Housings