BOREHOLE PLUNGER PUMP AND PROTECTION METHOD OF UPPER PART OF PLUNGER AGAINST IMPACT OF PUMPED LIQUID Russian patent published in 2011 - IPC F04B47/00 

FIELD: engines and pumps.

SUBSTANCE: borehole plunger pump includes cylinder with suction valve in its lower part. In cylinder there is hollow cylindrical plunger with outlet holes in upper part and discharge valve in lower part. Sealing device is made in the form of closed cavity filled with lubricating liquid formed with side surface of plunger and annular projections on inner side of cylinder, which are located in middle part of cylinder and provided with sealing rings. In upper part of cylinder after annular projections, at the point where plunger leaves the cylinder there is separating chamber filled with buffer liquid with specific weight exceeding specific weight of pumped liquid. In lower extreme position of plunger the contact surface of buffer liquid with pumped liquid shall be below outlet holes in plunger.

EFFECT: partial insulation and protection of plunger-cylinder friction pair against action of pumped liquid and its ingredients.

9 cl, 1 dwg