Dirac Industries

Circulation Heaters

are used to heat a flow of liquid and consist of an immersion heater mounted in a tubular vessel. They feature a main flange or nozzle for the immersion heater and two additional flanges or nozzles for liquid flow. Typically, the inlet is near the heater terminal enclosure, with the outlet at the vessel’s far end.

For high output requirements, especially in limited spaces, heaters can be stacked, connecting the outlet of one heater to the inlet of another. When selecting a circulation heater, it is crucial to consider the liquid’s nature, flow rate, operating pressure, and any specific calculation codes applicable to the process or location.

Due to their small volume, circulation heaters can quickly respond to temperature changes, making a thyristor system preferable to on/off control. On/off control may suffice if the circulation heater is part of a loop heating a large tank, with the sensor mounted in the main tank or heater inlet.

Precaution:  Ensure the heater is not energized without liquid in the system or when there is no flow. All our circulation heaters can be equipped with safety thermostats, which should not replace dedicated temperature and flow devices.

The European Pressure Directive 97/23/EC (PED) applies to systems with a maximum allowable pressure of 0.5 barg or above. DIRAC Industries offers equipment meeting the Directive’s requirements for Categories I, II, III, and IV. Providing full process information before ordering is essential for our engineers to ensure PED compliance.