US 5,074,154 AGranted

Fluid sampling pump

AssigneePrecision General, Inc.

InventorsPaul V. Allen, Spencer M. Nimberger, Robert L. Ward

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Abstract

A sampling pump is provided suitable for pumping a discrete quantity of either a liquid or a gas per pump stroke from a flow line to a sample vessel. An operator unit drives a piston within the pump bore, and controls the stroke of the piston and thus the quantity of fluid pumped per stroke. A balanced check valve mechanism controls flow from the pump bore to the pump outlet port, and is provided within and carried by the piston. Line pressure acts on the operator end of the piston to assist the operator in driving the piston during its power stroke. A manifold may be secured to the pump body, and has a flow path therein which is in communication with the inlet port to the pump bore. The pump may also be used for injection purposes to introduce a selected quantity of fluid to a high pressure line.

Claims23

Dependent claims

A fluid sampling pump for withdrawing pressurized sample fluid from a flow line and for pumping a preselected quantity of sample fluid with each pump driving stroke from the pump to a sample vessel, the sampling pump including a pump body defining a pump bore therein having a central axis, a piston slideably moveable within the pump bore and having a fluid inlet end and an opposing operator end, a fluid sample inlet port open to sample fluid in the flow line, a fluid sample outlet port for transmitting fluid from the pump bore .to the sample vessel, and a line pressure port in fluid pressure communication between the pump bore and the pressurized sample fluid in the flow line, an inlet valve for selectively controlling sample fluid flow from the flow line through the fluid sample inlet port, an operator unit for periodically reciprocating the piston within the pump bore, and a controller for regulating the stroke of the piston within the pump bore and thereby the quantity of fluid pumped with each pump driving stroke, the fluid sampling pump further comprising:

a balanced check valve seat radially within and carried by the piston;
a balanced check valve seal radially within and carried by the piston for sealing engagement with the check valve seat to control fluid flow from the pump bore to the fluid sample outlet port:
a compression member radially within and carried by the piston, the compression member being axially moveable within the piston in response to fluid pressure in the outlet port for biasing the balanced check valve seal toward the check valve seat when pressure in the outlet port is greater than pressure in the line pressure port:
and
a central plunger radially within and carried by the piston, the central plunger being axially moveable within the piston in response to pressure in the line pressure port for acting on the compression member and biasing the balanced check valve seal toward the check valve seat when pressure in the line pressure port is greater than pressure in the outlet port.

2 more elements

A fluid sampling pump for pumping a selected quantity of sample fluid with each pump driving stroke from a flow line to a sample vessel, the sampling pump including a pump body defining a pump bore therein having a central axis, a fluid sample inlet port at a lower end of the pump bore and open to sample fluid in the flow line, a fluid sample outlet port for transmitting fluid from the pump bore to the sample vessel, and a line pressure port in fluid pressure communication between the pump bore and the pressurized sample fluid in the flow line, a piston slideably moveable within the pump bore and having a fluid inlet end and an opposing operator end, an operator unit for reciprocating the piston within the pump bore, and a rod connected at one end to the operator unit and at an opposing end to the piston for mechanically interconnecting the piston and the operator unit, the fluid sampling pump further comprising:

a balanced check valve seat;
a balanced check valve seal for sealing engagement with the check valve seat to control fluid flow from the pump bore to the fluid sample outlet port:
a plunger axially moveable in response to pressure in the line pressure port for biasing the balanced check valve seal toward the check valve seat;
and
the pump body having a pressure transmitting passageway for continually maintaining fluid communication between the line pressure port and the operator end of the piston, such that sample fluid pressure in the flow line assists the operator unit in moving the piston toward the sample inlet port.

2 more elements

A method of operating a fluid sampling pump to withdraw pressurized sample fluid from a flow line and pump a preselected quantity of sample fluid with each pump driving stroke from the pump to a sample vessel, the sampling pump including a pump body defining a pump bore therein having a central axis, a fluid sample inlet port open to sample fluid in the flow line, a fluid sample outlet port for transmitting fluid from the pump bore to the sample vessel, and a line pressure port in fluid pressure communication between the pump bore and the pressurized sample fluid in the flow line, an inlet valve for selectively controlling sample fluid flow from the flow line through the fluid sample inlet port, a piston slideably moveable within the pump bore and having a fluid inlet end and an opposing operator end, and an operator unit for reciprocating the piston within the pump bore, the method comprising:

forming an outlet check valve seat radially within and carried by the piston:
positioning an outlet check valve seal member radially within and carried by the piston for sealing engagement with the outlet check valve seat to control fluid flow from the pump bore to the fluid sample outlet port;
positioning a plunger radially within and carried by the piston, the plunger being axially moveable within the piston in response to pressure in the line pressure port to bias the check valve seal member toward the check valve seat when pressure into the line pressure port is greater than pressure in the outlet port:
positioning a compression member radially within and carried by the piston between the plunger and the outlet check valve seal member, the compression member being axially movable within the piston in response to pressure in the outlet port to bias the check valve seal member toward the check valve seat when pressure in the outlet port is greater than pressure in the line pressure port;
and
maintaining fluid communication between the line pressure port and the operator end of the piston, such that sample fluid pressure in the flow line continually assists the operator unit in moving the piston toward the sample inlet port.

3 more elements

Dependencies are inferred from the claim text.