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 metallic tube, which is fixed in a metallic 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 metallic tube or a digital indicator is used to measure the temp outside the metallic tube surface (Only in digital model)
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, temperature is noted down. The temperature is the dew point and corresponding to this, the moisture content of the air can be seen from the table indicated in ppm, thus determining its dryness.