Portable Dew Point Meter XPDM

Hand-held, Battery Operated

COSA XPDMThe Portable Dew Point Meter Model XPDM is a battery operated, hand-held instrument designed for situations where quick and accurate dew point measurements have to be made. With the XPDM, accurate spot-checks of moisture in air or gases can be made faster and easier than ever, over the range of -148°F to +68°F (-100°C to +20°C) dew point.

Operating Principle

Aluminum oxide sensors adsorb much faster than they desorb water molecules. It is an advantage, if at the beginning of the measurement. the sensor is dryer than the sample to be measured. The XPDM 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.

Sample Cell Design

All surfaces in contact with the sample are made from 316 stainless steel and are electropolished to assure rapid equilibrium with the sample. Sensor and piston slide through spring-loaded PTFE seals protecting the sample cell as well as the desiccant cartridge from intrusion of wet air or gas.

The sample cell can measure gas flows up to 20 liters per minute. The flow rate has no effect on the measurement. The pressure in the sample cell is near atmospheric and should not exceed 2 bar (29 psi)

The instrument computer gives read out at any sensor pressure as well as at any line pressure the user enters for the particular sample. No correction is needed for different gases.