Flanged electric heaters in atex-ex execution - systems sector

Thanks to its experience in the Atex (Explosive Atmosphere) sector on electric heaters and to the product certification obtained at the Cesi in Milan, Reart produces Electric heaters on flange in Exd execution, for heating liquids and gases of all kinds for the plant sector, Chemical and Petrochemical in a potentially explosive environment (Zone 1 & 2).

The Atex-ex execution flange heaters are studied and designed to fix the electric heater to the process to be heated, through a special connection flange that is defined according to the UNI or ANSI 16.5 standards. Unlike the process connection flanges, they can be designed and built according to customer specifications or requirements.

This type of heater is used for heating fluids in:

  • Storage tanks under pressure, in direct contact with the fluid to be heated
  • Tubes in line with the process fluid to increase its operating temperatures.

The electric flange immersion heaters are suitable for heating all non-corrosive process fluids. They consist of one or more U-bent heating elements welded to the main connection flange by TIG welding, complete with electrical connections, safety devices and relative protection casing.

All the heating elements welded to the main flange of the heater are tested through hydraulic tests at well-defined pressures according to the design conditions indicated by the customer.

Thanks to the hydraulic test performed by Reart on the welded heater, it is possible to guarantee the tightness of the welds of the heating elements to the flange, declaring this test in the final test certificate issued together with the product and issued by Reart.

General technical characteristics of the Flanged Electric Heaters in Ex execution.

The flange Electric heating elements in Exd execution are essentially composed of:

  • Process heater connection flange.
  • Electric heating beam with dimensions and materials according to the process fluid
  • splitters for cooling and heat exchange between the electric bundle and the fluid
  • Explosion Proof execution electric protection group and head
  • Thermal sensors for regulation and safety of the system and heater.

The connection flange of the electric heater is defined and sized according to the customer already in the offer phase, so that the heater can be sized according to process data.

The design for this type of heater is carried out according to the functional data requested by the customer, and also considering and evaluating dimensional, physical, chemical and thermodynamic characteristics of the fluid to be heated, so as to guarantee a very precise and accurate choice of the sizing of the heater and building materials. The size of the flange depends on the electrical conditions imposed by the regulations for Atex execution.

The electrical power installed on Atex flanged electric heaters can vary up to thousands of kW with the aid of settings according to customer specifications, Reart engineering and reference standards for the sizing of heaters in Exd execution.

Usually, we can have the following reference design parameters for the sizing of the flange electric heaters:

  • Flanges up to 24”(DN600) in accordance with UNI or ANSI B 16.5 specifications in carbon steels, stainless steels and nickel alloys.
  • Diameter of the heating elements that form in the tube bundle 10 and 15 mm;
  • Material of the heating elements in carbon steel, stainless steel 304-321 316 (L), or much more noble alloys such as Incoloy 800.
  • Protection rating of the electrical enclosures of the heaters IP55, IP65, IP66;
  • Installed electrical power up to 1.65 MW per single heater.
  • Maximum immersion length of the electric beam about 3 meters.

All electric flange heaters in Atex execution are equipped with thermal sensors such as thermostats and/or thermocouples or temperature probes (PT100) to protect the system and the heater itself in the event of abnormal or unexpected situations on the system.

Atex flanged heaters can be equipped with the following accessories:

  1. 4-20mA temperature transmitters in SIL execution according to IEC 61508
  2. Process control and safety sensors and heater (thermostats, PT100 temperature probes, thermocouples)
  3. Power and safety cable glands in Exd execution
  4. Electric control panel and heater control in a safe and classified area
  5. Local command and control panel in classified area (Atex).
  6. Anti-condensation heater (prevention against humidity).