US 5,238,372 AGranted

Cooled spool piston compressor

AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration

InventorBrian G. Morris

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Abstract

A hydraulically powered gas compressor receives low pressure gas and outputs a high pressure gas. The housing of the compressor defines a cylinder with a center chamber having a cross-sectional area less than the cross-sectional area of a left end chamber and a right end chamber, and a spool-type piston assembly is movable within the cylinder and includes a left end closure, a right end closure, and a center body that are in sealing engagement with the respective cylinder walls as the piston reciprocates. First and second annular compression chambers are provided between the piston enclosures and center housing portion of the compressor, thereby minimizing the spacing between the core gas and a cooled surface of the compressor. Restricted flow passageways are provided in the piston closure members and a path is provided in the central body of the piston assembly, such that hydraulic fluid flows through the piston assembly to cool the piston assembly during its operation. The compressor of the present invention may be easily adapted for a particular application, and is capable of generating high gas pressures while maintaining both the compressed gas and the compressor components within acceptable temperature limits.

Claims23

Dependent claims

A hydraulically powered gas compressor for receiving a low pressure gas and outputting a high pressure gas, the gas compressor comprising:

a compressor housing assembly having a left end housing portion, a right end housing portion, and a center housing portion, the compressor housing defining an elongate cylinder having a respective left end chamber, an opposing right end chamber, and a center chamber axially spaced between the left end chamber and the right end chamber;
the center chamber of the cylinder having a cross-sectional area less than the cross-sectional area of each of the left end chamber and the right end chamber;
a piston assembly axially movable within the elongate cylinder, the piston assembly having a left end closure with a left end face, a right end closure with a right end face, and a center body axially spaced between the left end closure and the right end closure;
the center body of the piston assembly having a cross-sectional area less than the cross-sectional area of each of the left end closure and the right end closure, the left end closure slidably movable within the left end chamber, the right end closure slidably movable within the right end chamber, and the center body slidably movable within the center chamber;
a left end hydraulic input port for inputting pressurized hydraulic fluid to the left end chamber for acting on the left end face of the piston assembly;
a right end hydraulic input port for inputting pressurized hydraulic fluid to the right end chamber for acting on the right end face of the piston assembly;
the left end closure of the piston assembly and the center housing portion of the compressor housing defining a first annular compression chamber radially inward of the left end housing portion and radially outward of the center body of the piston assembly;
the right end closure of the piston assembly and the center housing portion of the compressor housing defining a second annular compression chamber radially inward of the right housing portion and radially outward of the center body of the piston assembly;
the compressor housing having a first gas input line extending to the first annular compression chamber and a first gas output line from the first annular compression chamber;
and
the compressor housing having a second gas input line extending to the second compression chamber and a second gas output line from the second annular chamber.

8 more elements

A hydraulically powered gas compressor for receiving a low pressure gas and outputting a high pressure gas, the gas compressor comprising:

a compressor housing assembly having a left end housing portion, a right end housing portion, and a center housing portion, the compressor housing defining an elongate cylinder having a respective left end chamber, an opposing right end chamber, and a center chamber axially spaced between the left end chamber and the right end chamber;
the center chamber of the cylinder having a cross-sectional area distinct from the cross-sectional area of each of the left end chamber and the right end chamber;
a piston assembly axially movable within the elongate cylinder, the piston assembly having a left end closure with a left end face, a right end closure with a right end face, and a center body axially spaced between the left end closure and the right end closure;
the center body of the piston assembly having a cross-sectional area distinct from the cross-sectional area of each of the left end closure and the right end closure, the left end closure slidably movable within the left end chamber, the right end closure slidably movable within the right end chamber, and the center body slidably movable within the center chamber;
a left end hydraulic input port for inputting pressurized hydraulic fluid to the left end chamber for acting on the left end face of the piston assembly;
a right end hydraulic input port for inputting pressurized hydraulic fluid to the right end chamber for acting on the right end face of the piston assembly;
a first annular compression chamber defined by the center housing portion, the left end housing portion, and the piston assembly;
a second annular compression chamber defined by the center housing portion, the right end housing portion, and the piston assembly;
the compressor housing having a first gas input line extending to the first annular compression chamber and a first gas output line from the first annular compression chamber;
the compressor housing having a second gas input line extending to the second compression chamber and a second gas output line from the second annular chamber;
and
at least one of the left end closure and the right end closure of the piston assembly having a restricted flow passageway therethrough, the other of the left end closure and the right end closure having a flow port therethrough, and the center body of the piston assembly having a flow path extending between the restricted passageway and the flow port, such that hydraulic fluid flow through the piston assembly cools the piston assembly.

9 more elements

A system for utilizing pressurized hydraulic fluid to convert a low pressure gas to a high pressure gas, the system comprising:

(a) a compressor including
a compressor housing assembly having a left end housing portion, a right end housing portion, and a center housing portion, the compressor housing defining an elongate cylinder having a respective left end chamber, an opposing right end chamber, and a center chamber axially spaced between the left end chamber and the right end chamber;
the center chamber of the cylinder having a cross-sectional area distinct from the cross-sectional area of each of the left end chamber and the right end chamber;
a piston assembly axially movable within the elongate cylinder, the piston assembly having a left end closure with a left end face, a right end closure with a right end face, and a center body axially spaced between the left end closure and the right end closure;
the center body of the piston assembly having a cross-sectional area distinct from the cross-sectional area of each of the left end closure and the right end closure, the left end closure slidably movable within the left end chamber, the right end closure slidably movable within the right end chamber, and the center body slidably movable within the center chamber;
a left end hydraulic input port for inputting pressurized hydraulic fluid to the left end chamber for acting on the left end face of the piston assembly;
a right end hydraulic input port for inputting pressurized hydraulic fluid to the right end chamber for acting on the right end face of the piston assembly;
a first annular compression chamber defined by the center housing portion, the left end housing portion, and the piston assembly;
a second annular compression chamber defined by the center housing portion, the right end housing portion, and the piston assembly;
the compressor housing having a first gas input line extending to the first annular compression chamber and a first gas output line from the first annular compression chamber;
and
the compressor housing having a second gas input line extending to the second compression chamber and a second gas output line from the second annular chamber;
(b) a control valve for selectively regulating flow of hydraulic fluid to one of the left and the right hydraulic input ports;
and
(c) a pressure sensor responsive to hydraulic fluid pressure for activating the control valve.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/998,062Filed 29 Dec 1992
Granted: 24 Aug 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

F01L 25/06
By working-fluid of machine or engine, e.g. free-piston machine: arrangements with main and auxiliary valves, at least one of them being fluid-driven
F04B 9/115
With two mechanically connected pumping members: reciprocating movement of the pumping members being obtained by two single-acting liquid motors,…
F04B 31/00
Free-piston pumps specially adapted for elastic fluids
F01L
Cyclically operating valves for machines or engines