BOTTOM-HOLE PUMP Russian patent published in 2018 - IPC F04B47/00 

FIELD: oil industry.

SUBSTANCE: invention relates to oil production technique, in particular to deep rod well pumps using in oil industry. Pump includes a cylinder with a plunger, suction and discharge valves. In the lower part of the cylinder there is a container with process fluid equipped with a check valve and a veil with a flow path of process liquid, holes on the cylinder for process liquid supplying to the gap of the plunger pair and for entering the borehole liquid to pump suction. At the lower end of the plunger an annular groove is provided and in the upper end of the cylinder there is an area of passage coinciding with the groove on the plunger at its upper end position and connecting an annular hole formed by a cylinder and a casing with an expanded gap in the plunger pair. Container is provided with a separating spring-loaded piston.

EFFECT: reliability and longevity of the pump operation is improved by simplifying the design in which the fluctuation of the process liquid into the gap of the plunger-cylinder pair occurs both due to a depletion in the under-plunger space and due to the upward movement of the spring-loaded piston installed at the bottom of the casing; the expanded clearance due to the annular groove on the plunger facilitates the passage of lubricant for the plunger-cylinder pair and increases its volume.

1 cl, 1 dwg