Threaded electric immersion heaters

Threaded immersion electric heaters are the optimal and economical solution to meet the heating needs of various process fluids for all application sectors: civil and industrial. They facilitate the maintenance of the systems thanks to their ease of replacement.

The heat is generated by the standard tubular heater in contact with the fluid to be heated and released during its operation when the heater is powered.

 This type of heater is designed to be inserted on threaded connections welded directly on pressure tanks or storage tanks in direct contact with the fluid to be heated.

Thanks to this feature, it is possible to make heaters with high power and small dimensions, with an effective heat exchange.

According to the indications for use of the immersion heater defined by the customer (type of fluid to be heated, operating temperature, available dimensions and operating pressure), all the useful and necessary characteristics for defining the product are pre-established by the technical office. This guarantees the product a long operation and a high quality.

Reart gives the possibility to order electric heaters in single-phase or three-phase execution depending on the type of power supply available.

Immersion heaters consist of:

  • threaded screw connection to be screwed onto the sleeve welded to the process
  • heating elements
  • any heat exchange splitters
  • IP40 ÷ IP65 electrical protection casing
  • power and safety cable glands (if provided)
  • regulation or safety thermostat
  • ground connection
Threaded electric immersion heaters

Materials and dimensions applicable to threaded immersion electric heaters.

All threaded connection immersion heaters are customized to the type of application and operating conditions. We can have:

Threaded connection size
¾" gas- 1 ¼" gas -1 ¼" gas - 2" gas -2 ½ gas (also available in BSP, NPT)
Brass - Stainless steel 316L /304 - Titanium
Armour Heating element
Ø 8,5- Ø10- Ø15
Copper - Aisi 321 or 316L - Titanium - Incoloy 800 or 825
Resistive wire
Different sections
NiCr 80/20
Magnesium Oxide MgO
For all armour diameters
Grade 'M' - Grade 'HA' high temperatures
Protective case
IP40 or IP65
Makralon - Polyamide
Connection terminals
Threaded or faston
Carbon steel or Aisi 304
Rigid rod thermostats
Faston connection for single-phase resistors
Brass rod
Capillary bulb thermostat
Automatic reset regulation or manual reset safety
Copper or stainless steel bulb and capillary

For processes where the heater is used in highly corrosive environments, we recommend the use of special electrict heaterswith solutions more suitable for the type of application.
Two types of welding are used based on the manufacture materials chosen for making the immersion heater. silver-based brazing is used for threaded connections in brass, while for threaded connections in stainless steel series 300 or Titanium, Tig welding is used.
At the request of the customer, Reart allows you to insert various types of thermostats to guarantee the proper functioning of the heater, in order to guarantee its operation and safety. The following thermostat models can be mounted on the heater (also visible in the dedicated section “Instrumentations, Instruments, Instrumentations, accessories and spare parts” :

  • single-phase regulation thermostats with automatic reset. Several adjustment scales including:

1-Scale 4-40°
 2- Scale 30-90° C

3-Scale 0-100° C

4-Scale 50-300° C

5-Scale 20-500° C

  • single-phase safety thermostats with manual reset with the following operating scales:
  • Scale 0-150°C
  • Scale 20-500° C
  • single-phase safety thermostats with fixed setting and manual reset:

1-Calibration 99° C

  • three-phase regulation thermostats with automatic reset:

1-Scale 30-90°C

  • thermostats with single-phase and three-phase regulation and safety:

1-regulation with manual reset 8-75° C safety with manual reset 98° C.

  • thermostats for single-phase rigid rod heaters “RTR” model with automatic reset adjustment, scale 20-80° C.
  • thermostat for single-phase rigid rod heaters “RTD” model with automatic reset adjustment, scale 20-80° C and safety up to 92° C.

All thermostat models are with SP-DT changeover contact.

The electric immersion heaters on threaded connection are suitable for process temperatures up to 150° C and operating pressures of 15 bar.

With higher temperatures, special “cold head” return executions are implemented to protect the electrical enclosure of the heater connections, with relative regulation and/or safety thermostat.


  • Water heating (pressurized storage tanks)
  • Oil heating in control units
  • Machinery for the food industry
  • Antifreeze systems for storage tanks
  • Fuel oil heating
  • Indirect heating

Special executions are also provided on request and customer specifications.

Threaded immersion electric heaters are applied for the following reference sectors: