Flanged Immersion Heater

Flanged industrial immersion heaters are amongst the most popular heaters owing to wide customization, easier installation and operations in stringent environment. Made by brazing or welding flange with several hairpin elements or bulge tubular elements, these are designed for heating chemical, petroleum and water based applications specially heat transfer fluids, medium and lightweight oils and water in tanks and pressure vessels. A thermocouple or RTD is often used within the bundle of elements to maintain the desired target temperature. Extra wiring boxes to make electrical connections are provided with it. Tubing known as a thermowell is used to protect thermocouples and heating elements. Different alloys and materials can be used to suit specific applications. For instance, steel flanges are used for deionized water, lubricant oils, heavy and light oils, waxes as well as mildly corrosive liquids and low flow gas and water tank heating.  Stainless steel flanged heating elements are used with mild and severe corrosive solutions and military applications. The sheath materials used can be steel, stainless steel, copper as well as exotic alloys such as incoloy.

Different sheath materials used have different operating temperatures and watt densities. While selecting the material these values must match your criteria. Table shown below will help to make an ideal selection.

 Sheath Material Maximum operating temperatures      Maximum Watt Densities


°F °C W/in2
INCOLOY 1600 870 100
304 stainless steel 1200 650 100
Steel 750 400 30



Note- For custom design requirements please contact sales@marathonheat.com

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Sheath Material

Copper, Steel, 304 Stainless steel, INCOLOY

Flange Material

Carbon steel, Stainless steel , Alloy 800 /  625 , Hastelloy

Flange size

2 to 42 inches

Flange Rating

150, 300, 600 or 900lb. pressure class ANSI

Design Temperature -40°C to 650°C
Design Pressure Up to 350 bar(g)
Heating Elements: Mineral filled insulated Heating Elements or Tubular heating Elements with Ni-Cr (80-20) as heating Coil and suitable outer sheaths.
Terminal Enclosure*: As required (Weather proof or Flameproof).
Control System

Thyristor control Panel + Local control Stations for effective temperature control & safe operation. (Safe area or Hazardous area)

Smaller Heaters : Thermostatic control

Protections & control:

Element Skin Temperature controls

process temperature control

Earth leakage protection.

Overload current protection.


Mostly Horizontal

For vertical installation, please refer Marathon Make “ L shape Immersion Heater”

Immersion Length Up to 240inch


0.260”, 0.315”, 0.375”, 0.430” or 0.475”, 0.625”


Thermocouple, RTD, Thermostat, Digitally controlled


Up to 600 V



Certification: Will be provided based n Requirement. ( U Stamp,  ATEX, IEC Ex, CCOE,)


Some of the typical applications of flanged immersion heaters with their specific attributes are shown in the table below.
Clean water, hot water storage, portable water, freeze protection of liquid Copper Steel
Hot water, steam boilers, mildly corrosive solutions (in rinse tanks, spray washers), vapor degreasers Incoloy Steel
Oils (light or medium), Gases, hydraulic oil, stagnant or heavy oils, lubricating oil, crude asphalt Steel Steel
Process water, soap and detergent solutions, Boiler and water heaters, deionized water, chemical baths Stainless Steel Stainless Steel
Severe corrosive solutions, demineralized water Incoloy Stainless Steel
  • Lightweight
  • Moisture proof available on all models.
  • Portable
  • No drilling holes required
  • Easy to install and to remove
  • Easy to maintain.
  • Allow for 1 or 3-phase operation.
  • Maximize heat transfer.
  • Provides uniform temperature control.
  • Moisture resistant.
  • Oxidation and corrosion resistant.
  • Built solidly.
  • Designed for safety.
  • Durable.