Difference between revisions of "Air Heaters"
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[[File:Air_heater1.jpg|thumb|right|Air heater]] | |||
[[File:Air_heater2.jpg|thumb|right|Air heater]] | |||
Air can be heated with open-coil heaters, tubular heaters, strip heaters and quartz heaters. The choice of one over the other depends mainly on volume, pressure and air velocity. To increase heater life, use a phase-angle fired or zero-cross fired ( SCR ) power control. | |||
Air heaters work by radiating heat into the passing air/fluid. Unfiltered air may contain dirt, grease and water which will reduce heater life, especially for open coil air heaters. Important is an air flow over the air heating element for some time even after the heater is turned off. Use a time delay relay for this. If the temperature sensor is far downstream from the air heating element, place an over-temperature sensor close to the air heater itself. We recommend the use of a flow switch in the airstream to avoid any overheating of the system in case airflow is insufficient. | |||
To calculate the approximate power requirement in kW: multiply the standard cubic feet per minute (scfm) by the temperature difference and divide by 3000. [kW = (SCFM x Delta T)/3000](example: to heat 100 scfm 100 degF you'll need 3.3 kW) | |||
Revision as of 07:24, 13 March 2012
Air can be heated with open-coil heaters, tubular heaters, strip heaters and quartz heaters. The choice of one over the other depends mainly on volume, pressure and air velocity. To increase heater life, use a phase-angle fired or zero-cross fired ( SCR ) power control.
Air heaters work by radiating heat into the passing air/fluid. Unfiltered air may contain dirt, grease and water which will reduce heater life, especially for open coil air heaters. Important is an air flow over the air heating element for some time even after the heater is turned off. Use a time delay relay for this. If the temperature sensor is far downstream from the air heating element, place an over-temperature sensor close to the air heater itself. We recommend the use of a flow switch in the airstream to avoid any overheating of the system in case airflow is insufficient.
To calculate the approximate power requirement in kW: multiply the standard cubic feet per minute (scfm) by the temperature difference and divide by 3000. [kW = (SCFM x Delta T)/3000](example: to heat 100 scfm 100 degF you'll need 3.3 kW)