Patent ID: 8555957
Filing Date: 2013-10-15
Classification: E21B

Abstract:
1. Crude oil production equipment, comprising a submersible pump, a driving shaft mounted in a bottom side of said submersible pump, a linear motor consisting of a stator and a rotor and adapted for moving said driving shaft up and down, an oil pipe for output of crude oil, a well casing surrounding said submersible pump and said oil pipe, a filter pipe surrounding said oil pipe within said well casing and having perforations for preventing the flow of sand and mud into said submersible pump, an outer passage defined in between said filter pipe and said oil pipe, an inner tube mounted in a bottom side of said oil pipe, an oil inlet defined in a top end of said inner tube in communication with said outer passage, an upper valve ball mounted in the top end of said inner tube and adapted for closing said oil inlet, a spring mounted in the top end of said inner tube and supporting said upper valve ball in a closed position to close said oil inlet, a hollow piston mounted in said inner tube and dividing the inside space of said inner tube into an upper chamber and a lower chamber, and a lower valve ball supported on a spring in a bottom side of said hollow piston and adapted for closing said hollow piston; wherein when said driving shaft is moved downwards by said linear motor, a suction force is produced to suck crude oil from said well casing into said outer passage and said upper chamber of said inner tube via said oil inlet and said hollow piston forces crude oil out of said lower chamber into an inner passage and then said outlet; when said driving shaft is moved upwards by said linear motor, said hollow piston forces crude oil out of said upper chamber into said lower chamber, and said driving shaft enters said upper chamber and said lower chamber to force crude oil out of said lower chamber into said inner passage and said oil outlet.