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Screw Plug Immersion Heaters

3-5 DAY LEAD TIME!

We have hundreds of industry standard screw plug immersion heater designs. General purpose and GRC Style enclosures. Various sheath, screw plug, and corrosion-resistant hardware materials are available. Optional thermocouples for control or high limit protection, plus a full range of thermostatic controls, can also be provided.

Can't Find What You Need? Contact Us, We'll Custom Design & Manufacture to Your Requirements!


General Purpose Enclosure-Screw Plug-No Tstat-255x183

General Purpose Enclosure - No Thermostat

3-5 DAY LEAD TIME!

2" & 2 1/2" NPT Sizes

 

General Purpose Enclosure-Screw Plug-With Tstat-255x183

General Purpose Enclosure With Thermostat

3-5 DAY LEAD TIME!

2" & 2 1/2" NPT Sizes

 

GRC Style Enclosure-Screw Plug-255x183

GRC Style Enclosures

3-5 DAY LEAD TIME!

2" & 2 1/2" NPT Sizes

Typical Screw Plug Immersion Heater Applications:

  • Boilers & Water Heating
  • Clean & Process Water
  • Freeze Protection & Winterizing
  • Heat Transfer Systems
  • Lube & Fuel Oil Heating
  • Parts Cleaning Solutions
  • Plating & Finishing Chemicals
  • Storage Tanks
  • Temperature Control Units
  • Wash Systems
  • Wax Heating
  • Waste Oil

Application Guidelines

The goal is to optimize the heater configuration to ensure the longest life possible, while minimizing overall product and life cycle costs. The general temperature, sheath material and watt density guidelines below can aid in proper heater selection for some common liquids. Contact Durex for further assistance.

Liquid Max. Operating Temps °F (°C) pH Level and/or Concentration Recommended Sheath Material Typical Plug Material Max. Watt Density W/in2(W/cm2)
Clean, Potable Water
212 (100) Neutral (pH 6 to 8) Copper Brass 60-90 (9.5-14)
Process Water & Weak Solution 212 (100) pH 5 to 9; 2-3% Incoloy®, 304SS Steel or 304SS 48 (7.5)
Demineralized, Deionized Water 212 (100) Neutral 304SS or 316SS (passivated) 304SS or 316SS 60 (9.5)
Weak (Acidic) Solutions* 210 (100) Up to 5-6% Incoloy®, 316SS Steel 48 (7.5)
Mildly Corrosive (Acidic) Solutions* 180 (80) 5-15% Incoloy®, 316SS 304SS or 316SS 20-30 (3.5)
Severely Corrosive (Acidic) Solutions* 180 (80) >15% Incoloy®, titanium, Teflon® 304SS or other 15-16 (2.5)
Caustic Soda 10% 200 (100) pH 14; 10% Incoloy® Steel 20-23 (3.5)
Caustic Soda 50% 250 (120) pH 14; 50% Incoloy® Steel 16 (2.5)
Fuel Oil 1 & 2; Kerosene Lube Oil SAE 10 to 30 200-250 (95-120) - Steel Steel 20-23 (3.5)
Fuel Oil 4 & 5; Lube Oil SAE 40 to 50 200-250 (95-120) - Steel Steel 15-16 (2.5)
Fuel Oil 6 & Bunker C 160 (70) - Steel Steel 6-8 (1.2)
Hydraulic Oil 100 (40) - Steel Steel 15-16 (2.5)
Ethlyene Glycol 300 (150) - Steel Steel 23-30 (3.5-4.5)
Glycerine 500 (260) - Incoloy® Steel 8-10 (1.5)
Molton Salt Bath 800 (425) - Steel, 321SS, Monel® Steel 23-30 (3.5-4.5)
Paraffin Wax 150 (65) - Steel or 304SS Steel 15-16 (2.5)
Molasses 100 (40) - 304SS or 316SS 304SS 4-5 (0.7)

* Sheath material and watt density dependent on type of acid, concentration, temperature, aeration, movement, etc.

  • Please note that the user accepts full responsibility for validating that a heater is suitable for a given liquid or gas heating application.
  • Ensure that heater elements are completely covered in liquid AT ALL TIMES. Failure to do so may cause the heater elements to operate in open air and fail prematurely, or worse, lead to ignition of flammable vapor mixtures, causing serious personal injury and equipment damage. Liquid level sensors are highly recommended.
  • Durex recommends the use of a thermostat or process controller as well as a high limit sensor and FM approved safety controller to prevent unexpected over temperature conditions.

 

Screw plug immersion heaters are constructed of hairpin bent tubular heater elements brazed or welded into threaded screw plugs. These heaters are inserted through a threaded hole or through a threaded coupling attached to a tank or vessel.  An electrical enclosure is installed to protect the heater terminals.

Screw Plug Immersion Heater Design Features

Standard Designs 1", 1 1/4 ", 1 1/2 ", 2", 2 1/2 " NPT Screw Plugs

  • Optional 1 1/2", 3" & 4" NPT plugs also available

Wide Variety of Material, Enclosure, Control and Power Rating Options

Brazed or Welded Construction

Integral Thermostats or Thermocouple

Recompacted Bends

c-UL Component Recognition Available

 

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