Related Knowledge of Pressure Dew Point
First, what's instrument to measure compressed air dew point?
Pressure dew point unit is ℃, but its connotation is the water content of compressed air, so measured dew point actually measure water content in the air. There will be many instruments to measure compressed air dew point, such as "mirror dew point instrument" can be the as cold source by using nitrogen, ether etc, "electrolytic hygrometer" can be as the electrolyte by using phosphorus pentoxide, lithium chloride etc. At present, the industrial area widely uses dedicated gas dew point meter to measure dew point of compressed air, such as British SHAW dew point instrument, its measurement range can reach -80 ℃. There is also German TESTO dew point instrument.
Second, what should pay attention when measuring compressed air dew point with dew point instrument?
It’s very careful and patient to measure air dew point for operation with dew point meter, especially when the measured water content of air is extremely low. The gas sampling equipment and connecting pipeline must be dry (drier than measured gas at least), the pipeline connection should be completely sealed, the gas flow rate should be selected according to regulations, and it requires a long enough pre-treatment time, it will bring a lot of error if careless. It is proved that the error is very large to measure "pressure dew point" of the compressed air treated through refrigerated dryer by using phosphorus pentoxide as the electrolyte "micro-moisture determinator". According to manufacturer explained that this is because compressed air will produce a "secondary electrolysis" in a testing process, making reading value is higher than the actual. And compressed air water content is about 1000PPM after treatment for refrigerated dryer, it has exceeded measurement range of this instrument. Therefore, this type of instrument should not measure compressed air dew point when it treated by refrigeration dryer.
Three, which parts should be measured for dryer's pressure dew point of compressed air?
Pressure dew point of the compressed air is measured with dew point meter, the sampling point should be placed in an exhaust pipe of the dryer, and sample gas can't contain n liquid water droplets. Other sampling points may have error what measured dew point.
Three, which parts should be measured for dryer's pressure dew point of compressed air?
Pressure dew point of the compressed air is measured with dew point meter, the sampling point should be placed in an exhaust pipe of the dryer, and sample gas can't contain n liquid water droplets. Other sampling points may have error what measured dew point.
This article from www.bitemantech.com by Muriel.zhou.
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