The present disclosure provides a two-stroke pumping method and oil production device, and relates to the technical field of oil production. The oil production device comprises a pump body, wherein the oil production device further comprises a central tube of a hollow structure, and the central tube is partially located in the pump body and coaxially arranged with the pump body; a traveling valve and a standing valve are arranged on the left side and the right side of the outer wall of the central tube respectively, and the traveling valve is arranged between the pump body and the central tube; the standing valve is located outside the pump body; the traveling valve and the standing valve are matched with the pump body and the central tube to form an oil pumping space; and an oil pumping assembly is further arranged in the oil pumping space.

The present disclosure provides a two-stroke pumping method and oil production device, and relates to the technical field of oil production. The oil production device comprises a pump body, wherein the oil production device further comprises a central tube of a hollow structure, and the central tube is partially located in the pump body and coaxially arranged with the pump body; a traveling valve and a standing valve are arranged on the left side and the right side of the outer wall of the central tube respectively, and the traveling valve is arranged between the pump body and the central tube; the standing valve is located outside the pump body; the traveling valve and the standing valve are matched with the pump body and the central tube to form an oil pumping space; and an oil pumping assembly is further arranged in the oil pumping space.

A valve for a reciprocating pump includes a housing, a first chamber, a second chamber, a first valve element, and a second valve element. The housing includes an inlet and an outlet. The first and second chambers are within the housing. The first chamber includes a first valve seat and is fluidly connected to the inlet. The second chamber includes a second valve seat and is fluidly connected to the outlet. The first valve element is disposed in the first chamber and includes a spring-loaded check valve element. The second valve element is disposed in the second chamber and includes a buoyant material.

A valve for a reciprocating pump includes a housing, a first chamber, a second chamber, a first valve element, and a second valve element. The housing includes an inlet and an outlet. The first and second chambers are within the housing. The first chamber includes a first valve seat and is fluidly connected to the inlet. The second chamber includes a second valve seat and is fluidly connected to the outlet. The first valve element is disposed in the first chamber and includes a spring-loaded check valve element. The second valve element is disposed in the second chamber and includes a buoyant material.

A rotary pump for a fluid metering system is provided. The rotary pump reciprocates, and is reversed by a signal from a limit switch that is deflected by an actuator arm on a rotating sleeve of the pump system. The rotary pump includes a plunger and optional stopper formed from a two-shot molding process, and including seals overmolded onto the head of the plunger and the head of the optional stopper.

A rotary pump for a fluid metering system is provided. The rotary pump reciprocates, and is reversed by a signal from a limit switch that is deflected by an actuator arm on a rotating sleeve of the pump system. The rotary pump includes a plunger and optional stopper formed from a two-shot molding process, and including seals overmolded onto the head of the plunger and the head of the optional stopper.

A paint sprayer includes an end bell, a motor connected to the end bell, a pump drive connected to the end bell, a pair of protrusions attached to an extending from the end bell such that each protrusion is cantilevered from the end bell, and a pump assembly comprising a pair of mounting holes and containing a piston. The pair of mounting holes is adapted to receive and slide onto the pair of protrusions to mount the pump assembly on the end bell as well as slide off of the pair of protrusions to remove the pump assembly from the end bell. The pump drive is configured to covert rotational motion output by the motor to reciprocal motion. The pump assembly is configured to pump paint when reciprocated by the pump drive while mounted on the end bell.

A plunger pump, including: a tubular cylinder that has an internal space communicating with inlet and outlet flow paths; and a piston that is movable along an axis of the cylinder, wherein a head of the piston includes, on an outer peripheral surface thereof, a sealing portion that is slidable against an inner peripheral surface of the cylinder, which includes a body tubular portion wherein the head is arranged during normal use, and a cleaning tubular portion wherein the head is arranged during cleaning, an inner peripheral surface of the cleaning tubular portion has an inner diameter equal to that of an inner peripheral surface of the body tubular portion, the cleaning tubular portion includes, on the inner peripheral surface thereof, at least one cleaning liquid circulation groove that is configured by a through hole or recess, and the cleaning liquid circulation groove extends obliquely with respect to the axis.

A plunger pump, including: a tubular cylinder that has an internal space communicating with inlet and outlet flow paths; and a piston that is movable along an axis of the cylinder, wherein a head of the piston includes, on an outer peripheral surface thereof, a sealing portion that is slidable against an inner peripheral surface of the cylinder, which includes a body tubular portion wherein the head is arranged during normal use, and a cleaning tubular portion wherein the head is arranged during cleaning, an inner peripheral surface of the cleaning tubular portion has an inner diameter equal to that of an inner peripheral surface of the body tubular portion, the cleaning tubular portion includes, on the inner peripheral surface thereof, at least one cleaning liquid circulation groove that is configured by a through hole or recess, and the cleaning liquid circulation groove extends obliquely with respect to the axis.

A fluid end assembly comprising a plurality of fluid end sections positioned in a side-by-side relationship. Each fluid end section comprises a housing made of multiple-piece construction. One or more pieces of the housing are configured to have a plurality of stay rods attached thereto. The stay rods interconnect the fluid end assembly and a power end assembly.