The portable dew point meter, is a battery operated, hand-held, hygrometer, designed for applications where quick and accurate dew point measurements have to be made.
The dew point meter, utilizes aluminum oxide sensors which adsorb water molecules much faster than they desorb water molecules. It is therefore an advantage, if at the beginning of the measurement the dew point sensor is dryer than the gas sample to be measured. The dew point meter keeps the sensor in dry storage until the measurement is taken. The sensor slides directly from the dry storage into the sample cell, without ever coming in contact with ambient air. After the measurement is completed, the sensor slides back into the dry storage, where it is dried down for the next sample.
High capacitance sensors have a very low residual capacitance when dry and saturate at a predesigned level of humidity above +20ºC (+68ºF). This allows a SpanCheck of the sensor by exposing the sensor to a saturated environment for one minute and adjusting the instrument to its upper range limit. It is preferred that the customer use a known gas to determine the saturated environment. The advantages of this are obvious: The dew point sensors can be field calibrated anywhere and anytime. Sensors do not have to be returned to the factory for recalibration, which also eliminates the need for a second stand-by sensor.