Poy Plastic Testing

Dew Point

Introduction

Dew point measuring Instrument to solve the dryness measurement problem of compressed instrument air/gas by measuring its dew point. This is an assembly of special alloy mettalic tube which is fixed in a mettalic block & transparent bowl. Block is having inlet connection of compressed air/gas whose dryness has to be measured. A glass Thermometer is used to measure the temp.inside the mettalic tube or a digital indicator is used to measure the temp outside the mettalic tube surface (in digital model)

Operation

Compressed air/gas is connected to the apparatus and is circulated inside the bowl around the tube at atmospheric pressure and vented to the atmosphere.The mixture of dry ice (Co2 ice) and acetone/ether lowers down the temp. of the tube, the temp. is measured with the help of glass thermometer / Digital temp.indicator. When the brightness of the tube becomes dull due to mist formulation on the tube temp. is noted down. The temp.is the dew point and corresponding to this, the moisture content of the air can be seen from the table indicated ppm, thus determining its dryness.Max.80 ppm moisture content air is recommended for instrumentation and the corresponding dew point is (-40° C).