| 摘要 |
A submersible pumping system comprises a piston that is axially moveable relative to a body between an extended position and a retracted position. A pump valve coupled to the body has a first position, where the pump valve supplies operating fluid so as to move the piston to the extended position, and a second position, where the pump valve supplies operating fluid so as to move the piston to the retracted position. The pumping system also comprises an upper stop that is coupled to the pump valve so that the pump valve is moved to the first position when the upper stop is engaged by the piston in the retracted position. The pumping system also comprises a lower stop that is coupled to the pump valve so that the pump valve is moved to the second position when the lower stop is engaged by the piston in the extended position. |
