Heaters, electric radiant type

The short-wave IR radiation can only be generated by an electric IR heater employing a tungsten heating element. A tungsten filament has small mass as well as low electrical resistance, which allows heavy current flow and very rapid heat up and cool down. The rate of response of various types of radiant heat sources can be an important criterion in the selection of a proper source for coating drying applications. 

A square sample of 100 x 100 mm is exposed to the radiant flux of an electric heater. The heater has the shape of a truncated cone (hence the name of the instrument) and is capable of providing heat fluxes to the specimen up to 100 kW/m. An electric spark plug is used for piloted ignition. Heater temperature is measured as an average of the readings of three thermoconples in contact with the coil. It is set and maintained at a certain level by a three-term controller. Calibration of heat flnx as a function of heater temperatnre is performed with a total heat flux meter of the Schmidt-Boelter type. Prior to testing, the heater temperatnre is set at the appropriate value resulting in the desired heat flux. 

---