Measurement of the relative humidity at temperatures > 100°C is important in a number of industrial applications ranging from drying process chambers to large baking ovens. The high process temperature is critical for the selection of the humidity sensor. Not too many sensors can measure sufficiently correct at these high temperatures. Pewatron has developed the high-accuracy (+/-2% RH) and reliable, long-life FCX-OHS transmitter for use in various industrial applications and for operating temperatures in a wide range from 100°C to 300°C. The FCX-OHS transmitter is widely used to control humidity in all zones of industrial baking ovens, and has thus become an important process optimization tool for maximizing the output and quality of bakery products.
The measurement principle of the sensing element in the FCX-OHS transmitter is based on the oxygen displacement compared to dry air with a content of 20.95 % oxygen. With the increase of humidity in the atmosphere the oxygen concentration will reduce to 0% in case of complete humidity saturation and for high temperatures > 100°C. The transmitter generates an output signal of 4 to 20 mA corresponding to 0 to 100% RH and temperatures above 100°C.
The stainless steel probe (M22 x 1.5) with the humidity sensor integrated into the tube, is intended for wall mounting by using a removable flange. The length of the probe can be chosen between 20 cm and 2500 cm. The sensor and the construction materials used for the sensor probe (metal parts, wires and connectors) are heat resistant up to 350°C and also resistant to high pressures of up to 20 bar. The probes are connected to the transmitter electronics using a 4-pole high-temperature cable. The sensor element is equipped with a dust and particle protection filter.
For more information, please visit http://www.pewatron.com.