Whether it’s an open coil duct heater, a tubular or a finned tubular duct heater, each duct heater serves the main purpose which remains the same – to heat up a large area in the most efficient and economical method. However, the type may vary based on their construction, advantages, disadvantages and functionality differences.
Tubular duct heaters are electric heat transferring products whose construction is composed of various components that include a terminal housing, individual elements and controls. At the tubular center, it has a heating resistive wire made of chrome and nickel alloy. Magnetic contactors can be present to ensure full power cut-off when needed. The power wiring is also set to standard values to meet your industrial requirements. An airflow switch is present to provide proper air flow near the heating elements. An automatic switch is present called primary thermal switch which is used to stop the whole unit when the temperature limit is reached to maximum value. As soon as the value of temperature comes below the maximum limit, the switch is reset on its own. Similar switch is present which is operated manually. It is called secondary thermal cut-off. A disconnect switch is present to interrupt the electric power supply at the time of heater’s service and maintenance. There is another relay whose purpose is to make sure the fan is ready and energized before the heater. This relay is called fan interlock relay. The duct heater has bushings to bear the mechanical stress on device. These bushings are made of steatite ceramic due to its high value of dielectric strength and resistivity to mechanical and thermal shocks.