FIELD: engines and pumps.
SUBSTANCE: device is intended for application in deep wells, or for pumping in shafts, and does not require pumps with high discharge at the outlet. Pump device of piston type comprises vertically oriented cylinder having upper part and bottom with the first hole. In cylinder, its upper part and bottom, there are, accordingly, the first and second overflow channels for liquid. In cylinder piston is installed with the possibility of reciprocal motion, which has surface affected by pressurised liquid in direction of piston displacement. Hollow piston stem is connected to piston, which passes under piston with sliding through the first opening. Below cylinder there is overload chamber. Piston stem with sliding passes into overload chamber and has the third relief channel for hydraulic connection with it. In the third relief channel there is the first flow valve installed. There is also the fourth relief channel, which passes from overload chamber to source of pumped liquid, and second flow valve installed in it.
EFFECT: makes it possible to supply liquid in direction opposite to hydraulic discharge.
11 cl
