Drainage device

Drainage device Drainage device is the important part of the oil well pump, which is mainly used for the sealed valve cages,For example, the whole barrel pump,special pump and so on .Its function is drain off the oil in the down-holestring when put forward in mining pump need ground. Product details: Drainage device is the important part of the oil well pump, which is mainly used for the sealed valve cages,For example, the whole barrel pump,special pump and so on .Its