US20140013776A1

US20140013776A1 - System, apparatus and method for compressor hub with an integrated rectifying system for dc flow

Info

Publication number: US20140013776A1
Application number: US14/026,261
Authority: US
Inventors: Patrick CHAMPAGNE; Jeffrey R. Olson
Original assignee: Lockheed Martin Corp
Current assignee: Lockheed Martin Corp
Priority date: 2011-09-20
Filing date: 2013-09-13
Publication date: 2014-01-16
Also published as: US20140216064A1; US9863670B2; US20180128516A1; WO2013043883A1; US10254017B2

Abstract

A system, apparatus and method for a compressor hub assembly configured for use with a dual piston compressor is provided and includes a cylindrically shaped body having a centrally located inner wall and defining cylinder sealing surface for receiving and maintaining at least one compressor pump; a plurality of bores integrated within the body, the bores defining at least one fill port, a fluid inlet port, an output port, at least two compression bores, an off-center cross-bore interconnected with the one of the at least two compression bores, and at least one reservoir passages; at least one check-valve assembly disposed in the output port, the check valve assembly including a check valve, a valve seal and a valve retainer, wherein the use of the check valve assembly and the plurality of bores produces a continuous DC flow output when fluid is flowed through the compressor pump and into the hub assembly.

Description

CROSS REFERENCE TO RELATED APPLICATION(S)

This application claims priority to international application serial number PCT/US2012/056357, filed Sep. 20, 2012, and entitled “EXTENDED TRAVEL FLEXURE BEARING AND MICRO CHECK VALVE,” the contents of which are incorporated in full by reference herein and which claims priority to provisional application Ser. No. 61/536,993, filed Sep. 20, 2011, the contents of which are incorporated in full by reference herein.

FIELD OF DISCLOSURE

The present disclosure generally relates to systems, apparatus and methods for thermal management devices, and more specifically, to systems, apparatus and methods for a compressor hub assembly configured for use with compact, Joule-Thomson cryocoolers.

BACKGROUND

For some infrared (IR) sensor applications, it is necessary to meet two critical performance requirements with the same system design configuration: very fast cooldown time (seconds to reach sensor operating temperature) and long system operational run times (enabling the system to operate for thousands of hours without maintenance or service). The performance criteria for achieving very quick cooldown times to operating temperature and maintaining long operational run times are challenging to realize for applications where size, weight, and power (SWaP) are critical.
Conventionally, to satisfy the quick cooldown time criteria Joule-Thomson (JT) cryocoolers were employed. Briefly, in a JT cryocooler, cooling occurs when a non-ideal gas expands from high to low pressure at constant enthalpy. Cryocoolers based on JT gas expansion require a constant flow of pressurized gas to operate. Conventionally, such applications were powered by a bottle of compressed gas or a rotatory compressor (having bearings and/or rubbing contacting seals) in a closed loop system. Disadvantageously, each of the forgoing approaches have inherent life-limiting elements. Thus, in order to satisfy SWaP constraints and to incorporate a JT cryocooler into IR sensor applications such as a seeker on a missile or a surveillance sensor, a trade-off between quick cooldown time and operational run time needed to be balanced.
Although longer operational times can be realized by supplying a JT cryocooler with large reservoir volumes of very high pressure gasses or very large compressors to supply very high pressure gasses, such solutions add to the SWaP of the device. Thus, it is desirable to provide a compressor hub assembly which satisfies the two criteria of a rapid cooldown time and a long life while also providing a small form factor that produces a constant DC flow of pressurized gas from a dual piston-type compressor.

SUMMARY OF THE DISCLOSURE

The present disclosure is designed to provide a low cost and efficient compressor hub assembly operable for use with Joule-Thomson cryocooler systems, vapor compression refrigerators, low-noise amplifiers, superconducting electronics, sensors, photodetectors, cryogenic instruments, and the like. In example embodiments, the present disclosure relates to a compressor hub assembly operable for incorporation into a dual-piston compressor and connection to at least one compressor pump. In example embodiments, the compressor hub assembly generally comprises a metallic body having a generally cylindrical sealing surface for receiving and maintaining at least one compressor pump, a plurality of bores or through holes milled through and into the body, the bores defining at least one fill port, a fluid inlet port, an output port, at least one compression bore, an off-center cross-bore, reservoir passages, or any combination of the foregoing. In all example embodiments, the compressor hub assembly also incorporates at least one check-valve, at least one valve seal and at least one valve retainer disposed within the body and configured to produce a continuous DC flow output when fluid is flowed from the compressor pump and into the hub assembly. As is well known in the art, check valves allow fluid flow in one direction but restrict flow in the opposite direction. Such valves can be used in pulsating (AC) systems to “rectify” the oscillating pressure and produce unidirectional (DC) flow.
An example embodiment of the present disclosure includes a compressor hub assembly which forms the center portion of a dual-piston compressor unit where typically fluid or gas from each piston is combined and ported to the outside. Each piston is connected via a plurality of small ports to a plurality of check valves and connecting reservoirs. The positive and negative pressure pulses from each piston are captured by at one of the check valves and stored in the reservoirs. Additionally, the two pistons are connected in series so as to increase the final output pressure ratio. The result is a pressure flow output powerful enough to power a JT cryocooler. Advantageously, by utilizing the compressor hub assembly and check valve configuration herein described, the overall SWaP of the compressor is minimally affected.
An example embodiment provides a compressor hub assembly operable for use in a dual piston type compressor of a Joule-Thomson cryocooler used for rapidly cooling an infrared (IR) focal plane array (FPA) disposed in an integrated detector cooler assembly (IDCA).
Additional features and advantages of the disclosure will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the disclosure as described herein, including the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description present example embodiments of the disclosure, and are intended to provide an overview or framework for understanding the nature and character of the disclosure as it is claimed. The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the detailed description, serve to explain the principles and operations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present subject matter may take form in various components and arrangements of components, and in various steps and arrangements of steps. The appended drawings are only for purposes of illustrating example embodiments and are not to be construed as limiting the subject matter.

FIG. 1 is a perspective diagram of a conventional compressor assembly used with a pulse tube cryocooler;

FIG. 2 is a cross-sectional diagram of a conventional compressor assembly used with a pulse tube cryocooler;

FIG. 3 is a cross-sectional diagram of a conventional compressor hub assembly used with a pulse tube cryocooler;

FIG. 4 is a perspective diagram of a compressor assembly used with a Joule-Thomson cryocooler according to one example embodiment of the present disclosure;

FIG. 5 is a cross-sectional diagram of a compressor assembly used with a Joule-Thomson cryocooler according to one example embodiment of the present disclosure;

FIG. 6 is a cross-sectional diagram of a compressor hub assembly used with a Joule-Thomson cryocooler according to one example embodiment of the present disclosure;

FIG. 7 is a cross-sectional, perspective diagram of a compressor hub assembly used with a Joule-Thomson cryocooler according to one example embodiment of the present disclosure;

FIG. 8 is a cross-sectional, slightly off center, perspective diagram of a compressor hub assembly used with a Joule-Thomson cryocooler according to one example embodiment of the present disclosure;

FIG. 9 is an end view, schematic diagram of a compressor hub assembly used with a Joule-Thomson cryocooler according to one example embodiment of the present disclosure;

FIG. 10 is a cross-sectional, schematic diagram of a compressor hub assembly used with a Joule-Thomson cryocooler according to one example embodiment of the present disclosure;

FIG. 11 is a flow diagram of a compressor hub assembly used with a Joule-Thomson cryocooler according to one example embodiment of the present disclosure; and

FIG. 12 is a schematic diagram of an IDCA incorporating an FPA and a compressor hub assembly according to one exemplary embodiment.

DETAILED DESCRIPTION

The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which example embodiments of the disclosure are shown. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These example embodiments are provided so that this disclosure will be both thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like reference numbers refer to like elements throughout the various drawings. Further, as used in the description herein and throughout the claims that follow, the meaning of “a”, “an”, and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
The embodiments herein are designed to provide a low cost and efficient compressor hub assembly operable for use with compressors of Joule-Thomson cryocooler systems, Brayton refrigerators, vapor compression refrigerators, low-noise amplifiers, superconducting electronics, sensors, photodetectors, cryogenic instruments, and the like. Example embodiments presented herein disclose systems, apparatus and methods for a compressor hub assembly disposed within a compressor operable for use with avionic applications, and more particularly, missile applications, targeting systems and the like such that a constant DC flow of gas is generated and rapid and long-term cooling can occur. Advantageously, the disclosed systems, apparatus and methods for compressor hub assembly offers low-cost manufacturing of the hub assembly without an increase in the size or weight in comparison to conventional hub assemblies. Further, the disclosed systems, apparatus and methods for compressor hub assembly enables the use of long-life piston-type compressor systems used within avionic cooling applications. Still further, the disclosed systems, apparatus and methods for compressor hub assembly provides a rapid cool down time for an IR sensor application and provides a long life operation while satisfying SWaP constraints associated with the IR application. In all example embodiments, the disclosed systems, apparatus and methods for a compressor hub assembly include a series of check valves and reservoirs integrated into the body of the hub assembly such that a continuous DC flow output of fluid is produced without increasing the size and weight of the assembly. In example embodiments, the disclosed systems, apparatus and methods for a compressor hub assembly include a series of check valves and reservoirs integrated into the body of a hub assembly that is disposed within a dual-opposed piston type compressor such that a continuous DC flow output of fluid is produced without increasing the size and weight of the assembly.
Referring now to FIGS. 1-3, a conventional compressor hub assembly configured for use with a pulse tube cryocooler is shown. As shown, a compressor 10 is provided and has a generally cylindrical exterior surface 12 and two dome shaped end caps 14, 16. As best shown in FIG. 2, the compressor 10 includes a compressor hub assembly 18 operable for receiving and maintaining at least one compressor pump, at least one motor module for generating power to the compressor pump, and the two dome shaped end caps 14, 16. Integral to the compressor hub assembly 18 are a fill port 24 and an output port 26. In the illustrations shown, the output port 26 defines a mounting flat 28 for operative connection to a pressure pulse transfer line 30. In the illustrations shown, the at least one motor module has a motor power lead 32 connected to its external surface 12.
Referring specifically FIGS. 2 and 3, a cross-sectional diagram of the conventional compressor 10 is shown. As shown, the compressor 10 includes two compressor pumps 20A and 20 B located adjacent to each other such that they operate in an in-line manner. Each compressor pump 20A, 20B is seated within the compressor hub assembly 18 and encased by respective motor modules 22 a and 22B. Each of the compressor pumps 20A and 20B include a piston 34 disposed in a central shaft 36 and operable for moving along an axis of travel. The piston 34 may be equipped with forward and aft flexure spiral flexure bearings 38 connected to the shaft 36. At least one of the flexure bearings 38 may be equipped with inner clamp portions 40 and, in some variations, an outer clamp 42. The flexure bearings 38 may support a moving magnet assembly 44 that is part of the motor module 22 used to move the piston 34 in an oscillating manner. In addition, in the illustrations shown the compressor hub assembly 18 includes a common compression space or bore 46 interposed between the compressors pumps 20A and 20B and through a central wall of cylinder sealing surface 48 of the hub assembly 18. Further, in the illustrations shown, the compressor hub assembly 18 includes at least one backside common bore 50 and a mounting thread 52.
Referring now to the FIGS. 4-10, a compressor hub assembly 100 constructed in accordance with the present disclosure is illustrated. In example embodiments and as best shown in FIG. 4, the compressor hub assembly 100 is configured for use with a Joule-Thomson cryocooler and is incorporated in a dual piston-type compressor unit 102. As best shown in FIGS. 4 and 9, the compressor unit 102 is generally cylindrical in shape and comprises the centrally located hub assembly 100 connected to a pressure supply line 104 and a pressure return line 106. A pair of motor modules 108, 110 which houses compressor pumps 112, 114 are connected to a sealing surface 116 of the hub assembly 100. At least one motor power lead 114 is connected to each of the motor modules 108, 110. Dome end caps 118, 120 are connected to the motor modules 108, 110 thereby forming an enclosed unit.
In example embodiments and as best shown in FIGS. 5-6, the compressor hub assembly 100 is generally comprised a metallic body and has a generally cylindrical outer surface 122. In the example embodiments shown, the hub assembly 100 includes two end rings positioned at opposite ends and being operable for receiving two motor modules 108, 110 which, in turn, house two compressor pumps 112, 114 having movable pistons 126, 128 located therein. The hub assembly 100 includes a centrally disposed inner wall defining the cylindrical sealing surface 116 for receiving and maintaining the compressor pumps 112, 114 on each side. As best shown in FIGS. 7-10, a plurality of bores or through holes are provided through and into the hub assembly 100 and the sealing surface 116, the bores defining at least one fill port 130, a fluid inlet port 132, an output port 134, at least one compression bore 136, an off-center cross-bore 140, at least one reservoir 142, and internal reservoir connecting passages 144. In example embodiments and as best shown in FIGS. 5-6, and 10, the hub assembly 100 includes two compression bores 136A and 136B which are separated, with one compression bore 136A being interconnected with the off-center cross bore 140. The off-center cross bore 140 is disposed within the sealing surface 116 and extends along an axis perpendicular to the directional movement of the pistons 126, 128. Additionally, the off-center cross bore 140 interconnects the output port 134 and an internal reservoir 142 (FIG. 10).
In example embodiments, the output port 134 defines a mounting flat 146 at the exterior surface 122 of the hub assembly 100 and is operatively connected to the output or return line 106. The inlet port 132, outlet port 134, and reservoirs 142 are configured and sized to define a valve seat 148 operable for receiving a valve seal 150 and a check valve 152. In addition, inlet port 132, outlet port 134, and the reservoirs 142 are configured and sized to receive a valve retainer 154 which is positioned to maintain the check valve 152 against the valve seat 148. In example embodiments, the valve retainer 154 is flexible. In other example embodiments, a reservoir plug 156 may be disposed within openings of the reservoirs 142 to seal the compressor 102. Further, in example embodiments, the inlet port 132 is operatively connected to the fluid inlet or return line 104 for receiving fluid.
In all example embodiments, the compressor hub assembly 100 incorporates at least one check-valve 152, at least one valve seal 150 and at least one valve retainer 154 disposed within the reservoirs 142 of the hub 100 and configured to produce a continuous DC flow output when fluid is flowed through the compressor pump 112, 114 and into the hub assembly 100. In example embodiments, the check valves 152 allow fluid flow in one direction but restrict flow in the opposite directions. Advantageously, the hub assembly 100 and check valve 152 system described herein is operative for rectifying the oscillating pressure in pulsating (AC) systems to produce unidirectional (DC) flow. Configurations may use single or multiple valves in various combinations to produce such rectified flow. In the example embodiments shown, four check valves are provided and disposed within the reservoirs.
In specific regard to the check valves 152 of the present disclosure, a three component assembly may be provided which includes a base (not shown), a flexing element (not shown), and a cover (not shown). In some variations, a base serves as a structural part that mounts a flexing element and includes a metered flow port and valve seat. In example embodiments, the check valve components are made of metal. In example embodiments, the check valve components are made of stainless steel. Such metal variations may be well suited to assembly through spot welding. In other example embodiments, one or more of the check valve components may be made of materials such as plastics or polymers. In some such embodiments, the valve components may be held together using alternate techniques, such as epoxy or rivets.
Referring now to FIG. 11, a flow diagram of a compressor hub assembly is shown. As shown, a compressor hub assembly 118 which forms the center portion of a dual-piston compressor 300 is provided and fluid from each piston 112, 114 is routed, combined and ported to a supply line 104 to the external JT device 310. The fluid is then returned through a return line 106 to the compressor hub 118 for recirculation. Each piston 112, 114 is connected via small ports to a set or series of check valves 152 and connecting reservoirs 132, 134, 142. The positive and negative pressure pulses from each piston 112, 114 are captured by the check valves 152 and stored in the reservoirs 132, 134, 142. Additionally, the two pistons 112, 114 are connected in series so as to increase the final output pressure. The result is a pressure ratio and flow output powerful enough to power a JT cryocooler device 310.
Referring now to FIG. 12, an example embodiment of an IDCA 200 incorporating an FPA 220 and a compressor 250 having the compressor hub assembly 100 and check valves 152 system of the present disclosure is shown. As shown, the IDCA 200 includes a housing 201 for maintaining an FPA 220 which is disposed on a heat exchanger 202 therein. In certain example embodiments, the IDCA 200 may be connected to a gas pressure bottle 230 and compressor 250 via a diverter manifold 240, the gas bottle 230 having at least one gas contained therein. The gas may be any one or more of methane, ethane, argon, isobutene, nitrogen, propane, or mixtures thereof which are suitable for cooling systems. When the FPA 220 is activated, the diverter manifold 240 may be engaged or switched over to open-loop operation such that the gas from the gas pressure bottle 230 quickly cools the FPA 220 through the heat exchanger 202. In some variations, an FPA 220 may reach a desired operating temperature within ten seconds or less. Advantageously, by incorporating the compressor hub assembly 100 and check valves 152 of the present disclosure into a compressor 250, a closed-cycle, continuous operation Joule-Thomson cryocooler may be provided for rapidly cooling the infrared (IR) focal plane array (FPA) disposed in an integrated detector cooler assembly (IDCA). In such an example embodiment, the operating mode would not require the gas pressure bottle 230 and the same may be eliminated if desired.
When a desired operating temperature is achieved, the diverter manifold 240 may be switched over to a closed-loop operation, stopping the flow of gas from the gas pressure bottle 230 and engaging the compressor 250, which activates to maintain the FPA 220 at the desired operating temperature without a further significant loss of gas. Although not preferred for quickly cooling an FPA 220 to a desired operating temperature, a closed-loop compressor-based 250 cooling system enables the heat exchanger 202 to maintain the FPA 220 at the desired operating temperature for a relatively long period of time. In some cases, compressor-based cooling can allow for extended ongoing operation of an infra-red FPA 220 for up to an hour or longer.
In example embodiments, where the FPA 220 is intended for a single-use application, such as a missile seeker or a targeting feature of a single-use or limited-use weapon or device, the diverter 240 and/or charge port may be omitted. In further example embodiments, the diverter manifold 240 may be replaced with a different type of switch or switching paradigm, such as one or more valves.
The embodiments described above provide advantages over conventional devices and associated systems and methods. It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents. Furthermore, the foregoing description of the disclosure and best mode for practicing the disclosure are provided for the purpose of illustration only and not for the purpose of limitation—the disclosure being defined by the claims.

Claims

What is claimed is:

1. A compressor hub assembly configured for use with a dual piston compressor, the compressor hub assembly, comprising:

a generally cylindrically shaped body having a centrally located inner wall extending across the diameter of the body and defining a cylinder sealing surface for receiving and maintaining at least one compressor pump;

a plurality of bores integrated within the body, the bores defining at least one fill port, a fluid inlet port, an output port, at least two compression bores, an off-center cross-bore interconnected with the one of the at least two compression bores, and at least one reservoir passage;

at least one check-valve assembly disposed in the output port, the check valve assembly including a check valve, a valve seal and a valve retainer; and

wherein the check valve assembly and the plurality of bores provides a continuous DC flow output when fluid is flowed through the compressor pump and into the hub assembly.

2. The compressor hub assembly of claim 1, wherein the dual piston compressor is disposed within a Joule-Thomson cryocooler.

3. The compressor hub assembly of claim 1, wherein the input port is operatively connected to a pressure supply line for receiving fluid.

4. The compressor hub assembly of claim 1, wherein the output port is operatively connected to a pressure return line for exiting fluid.

4. The compressor hub assembly of claim 1, wherein the generally cylindrically shaped body includes a pair of ends rings positioned at opposite ends thereof an being configured to receive and maintain at least one motor module for housing the at least one compressor pump.

5. The compressor hub assembly of claim 1, wherein the off-center cross bore is disposed within the sealing surface and extends along an axis perpendicular to the directional movement of a piston housed within the at least one compressor pump.

6. The compressor hub assembly of claim 1, wherein the off-center cross bore interconnects the output port and at least one reservoir passage.

7. The compressor hub assembly of claim 1, wherein the output port defines a mounting flat at an exterior surface of the generally cylindrically shaped body.

8. The compressor hub assembly of claim 1, wherein the fluid inlet port, the output port, and the at least one reservoir are configured and sized to define a valve seat for receiving the valve seal and check valve of the check valve assembly.

9. The compressor hub assembly of claim 8, wherein the valve retainer is positioned to bias the check valve against the valve seat.

10. The compressor hub assembly of claim 1, wherein the valve retainer is flexible.

11. The compressor hub assembly of claim 1, wherein the at least one check valve provides a unidirectional fluid flow.

12. The compressor hub assembly of claim 1, wherein the compressor hub assembly modifies the oscillating pressure in pulsating (AC) systems to produce a unidirectional (DC) flow.

13. The compressor hub assembly of claim 1, wherein the at least one check valve includes four check valves disposed within four reservoir passages.

14. The compressor hub assembly of claim 1, wherein the compressor hub assembly is disposed within an integrated detector cooler assembly having a focal plane array disposed therein.

15. A compressor hub assembly configured for use with a dual piston compressor disposed in a Joule-Thomson cryocooler, the compressor hub assembly, comprising:

a generally cylindrically shaped body having a centrally located inner wall extending across the diameter of the body and defining a cylinder sealing surface for receiving and maintaining at least one compressor pump; and

a plurality of bores integrated within the body, the bores defining at least one fill port, a fluid inlet port, an output port, at least two compression bores, an off-center cross-bore interconnected with the one of the at least two compression bores, and at least one reservoir passage.

16. The compressor hub assembly of claim 15, further comprising at least one check-valve assembly disposed in the output port, the check valve assembly including a check valve, a valve seal and a valve retainer; and wherein the check valve assembly and the plurality of bores provides a continuous DC flow output when fluid is flowed through the compressor pump and into the hub assembly.

17. The compressor hub assembly of claim 15, wherein the off-center cross bore is disposed within the sealing surface and extends along an axis perpendicular to the directional movement of a piston housed within the at least one compressor pump and wherein the off-center cross bore interconnects the output port and at least one reservoir passage.

18. The compressor hub assembly of claim 16, wherein the at least one check valve provides a unidirectional fluid flow.

19. The compressor hub assembly of claim 15, wherein the compressor hub assembly modifies the oscillating pressure in pulsating (AC) systems to produce a unidirectional (DC) flow.

20. A method of cooling a focal plane array (FPA) disposed in an integrated detector cooler assembly (IDCA) to an operating temperature, the method comprising:

rapidly cooling the FPA to a desired operating temperature by providing a dual piston compressor disposed in a Joule-Thomson cryocooler and being connected to the FPA; and

maintaining the FPA at the desired operating temperature,

wherein the dual piston compressor includes a compressor hub assembly comprising a generally cylindrically shaped body having a centrally located inner wall extending across the diameter of the body and defining a cylinder sealing surface for receiving and maintaining at least one compressor pump; a plurality of bores integrated within the body, the bores defining at least one fill port, a fluid inlet port, an output port, at least two compression bores, an off-center cross-bore interconnected with the one of the at least two compression bores, and at least one reservoir passage; at least one check-valve assembly disposed in the output port, the check valve assembly including a check valve, a valve seal and a valve retainer; and wherein the check valve assembly and the plurality of bores provides a continuous DC flow output when fluid is flowed through the compressor pump and into the hub assembly.