POSITIVE-DISPLACEMENT PUMP ASSEMBLY Russian patent published in 2008 - IPC F04C11/00 F04C14/00 

FIELD: engines and pumps.

SUBSTANCE: proposed pump assembly is designed to be used in oil, gas and other industries for operation in IN-OUT mode at constant drive motor shaft RPM. The assembly incorporates a positive displacement driven pump, a bypass line connecting intake and discharge lines comprising a controlled shut-off valve. A gas-fluid discharge line is connected to the said bypass line, the aforesaid pump assembly job-sequence control unit. The output of the aforesaid unit is connected to the pump drive, its other output being connected to the bypass line controlled shut-off valve. The proposed assembly comprises also a fluid availability pickup connected to appropriate inputs of the aforesaid control unit and arranged in the intake line and additional controlled shut-off valves connected to appropriate inputs of the aforesaid control unit. One of the said additional valves is arranged in the gas-fluid discharge line, the other one being connected to the discharge line behind the bypass connection point. All aforesaid controlled shut-off valves shut off pumped fluid flow gradually.

EFFECT: ruling out hydraulic shocks in lines and pump components.

2 dwg, 3 tbl