Answer: When using a dew point meter to measure the dew point of air, especially when the water content of the measured air is extremely low, the operation must be very careful and patient. The gas sampling equipment and connecting pipes must be dry (at least drier than the measured gas), the pipe connection should be completely sealed, the gas flow rate should be selected according to regulations, and a sufficiently long pretreatment time is required. If you are not careful, it will cause a large error. Practice has proved that when using a "micro-moisture meter" with phosphorus pentoxide as an electrolyte to measure the pressure dew point of compressed air treated by a cold dryer, the error is very large. This is because the compressed air will produce secondary electrolysis during the test, making the reading value higher than the actual value. Therefore, this type of instrument should not be used when measuring the dew point of compressed air treated by a cold dryer.
