Pump, and earth-testable spacecraft capillary heat transport loop using augmentation pump and check valves

• US 5,816,313 A
• Filed: 02/25/1994
• Issued: 10/06/1998
• Est. Priority Date: 02/25/1994
• Status: Expired due to Term

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Baker, David
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): ATKINSON, CHRISTOPHER MARK
• Application Number:
  US08/201,733
• Time in Patent Office: 1,684 Days
• Field of Search: 165/911, 165/104.26, 165/104.22, 165/104.21, 165/41, 165/104.31, 165/104.24, 165/104.27, 165/104.23, 165/32, 417/543, 417/65, 137/533.11, 137/519.5, 137/606, 137/558, 257/285, 251/65, 62/115
• US Class Current: 165/41
• CPC Class Codes: F16K 15/048 Ball features
• CPC Class Codes: F25B 23/006 boiling cooling systems
• CPC Class Codes: F25B 2500/01 Geometry problems, e.g. for reducing size
• CPC Class Codes: F28D 15/043 forming loops, e.g. capillary pumped loops
• CPC Class Codes: Y10T 137/7873 Ball valves

Abstract

A spacecraft includes heat-generating payload equipment, and a heat transport system with a cold plate thermally coupled to the equipment and a capillary-wick evaporator, for evaporating coolant liquid to cool the equipment. The coolant vapor is coupled to a condenser and in a loop back to the evaporator. A heated coolant reservoir is coupled to the loop for pressure control. If the wick is not wetted, heat transfer will not begin or continue. A pair of check valves are coupled in the loop, and the heater is cycled for augmentation pumping of coolant to and from the reservoir. This augmentation pumping, in conjunction with the check valves, wets the wick. The wick liquid storage capacity allows the augmentation pump to provide continuous pulsed liquid flow to assure continuous vapor transport and a continuously operating heat transport system. The check valves are of the ball type to assure maximum reliability. However, any type of check valve can be used, including designs which are preloaded in the closed position. The check valve may use any ball or poppet material which resists corrosion. For optimum performance during testing on Earth, the ball or poppet would have neutral buoyancy or be configured in a closed position when the heat transport system is not operating. The ball may be porous to allow passage of coolant vapor.

Claims

1. A spacecraft, comprising:

a payload including means for performing a desired function and in the process generating undesired heat;

a cold plate coupled to said payload for absorbing said undesired heat therefrom, said cold plate including a liquid coolant input port, a capillary wick, and a coolant vapor outlet port, for accepting liquid coolant at said liquid coolant input port, and for wetting said wick and transferring said undesired heat to said coolant for causing said wick to transform said liquid coolant into said coolant vapor;

a heat exchanger including a coolant vapor input port and a liquid coolant output port, for receiving coolant vapor at said input port and extracting heat therefrom, for thereby condensing coolant vapor arriving at said input port of said heat exchanger into liquid coolant, which becomes available at said output port of said heat exchanger;

coolant coupling means coupled in a loop to said cold plate and to said heat exchanger, for coupling said coolant vapor from said coolant vapor output port of said cold plate to said coolant vapor input port of said heat exchanger, and for coupling said liquid coolant from said liquid coolant output port of said heat exchanger to said liquid coolant input port of said cold plate, whereby, under normal conditions of said loop, said capillary wick creates a vapor pressure which causes (a) circulation of coolant vapor through said loop from said cold plate to said heat exchanger, and (b) circulation of liquid coolant through said loop from said heat exchanger to said cold plate, and whereby, under other conditions, said capillary wick may become deprimed, thereby impeding circulation of coolant through said loop;

said coolant coupling means further comprising a coolant pump including (a)

a coolant reservoir including an input/output port coupled to said loop at a first location between said liquid coolant output port of said heat exchanger and said liquid coolant input port of said cold plate, for, when heated, rejecting liquid coolant from said reservoir into said loop at said first location, and for, when cooled, withdrawing liquid coolant from said loop;

(b) a first check valve coupled in said loop at a second location lying between said first location and said liquid coolant input port of said cold plate, oriented for allowing flow of liquid coolant through said loop in a direction toward said cold plate, and for blocking flow of liquid coolant from said cold plate;

(c) a second check valve coupled in said loop at a third location, and oriented to allow coolant flow through said loop in said first direction; and

(d) heat control means coupled to said coolant reservoir for controllably heating and cooling said reservoir during corresponding heating and cooling cycles, for thereby rejecting liquid coolant into said loop at said first location during heating cycles whereby liquid coolant tends to be driven through said first check valve toward said cold plate, and for withdrawing liquid coolant from said loop at said first location during cooling cycles, whereby said first check valve tends to close and said second check valve to open, thereby tending to draw coolant toward said first location from said second check valve, whereby successive heating and cooling cycles tend to develop a fluid pressure which tends to pump said liquid coolant toward said cold plate, which may wet said capillary wick.

2. A spacecraft according to claim 1, wherein said third location lies between said liquid output port of said heat exchanger and said first location.

6. A spacecraft according to claim 1, wherein said fluid reservoir stores a quantity of said coolant in the form of both liquid and vapor.

3. A spacecraft, comprising:

a payload including means for performing a desired function and in the process generating undesired heat;

a cold plate coupled to said payload for absorbing said undesired heat therefrom, said cold plate including a liquid coolant input port, a capillary wick, and a coolant vapor outlet port, for accepting liquid coolant at said liquid coolant input port, and for wetting said wick and transferring said undesired heat to said coolant for causing said wick to transform said liquid coolant into said coolant vapor;

a heat exchanger including a coolant vapor input port and a liquid coolant output port, for receiving coolant vapor at said input port and extracting heat therefrom, for thereby condensing coolant vapor arriving at said input port of said heat exchanger into liquid coolant, which becomes available at said output port of said heat exchanger;

coolant coupling means coupled in a loop to said cold plate and to said heat exchanger, for coupling said coolant vapor from said coolant vapor output port of said cold plate to said coolant vapor input port of said heat exchanger, and for coupling said liquid coolant from said liquid coolant output port of said heat exchanger to said liquid coolant input port of said cold plate, whereby, under normal conditions of said loop, said capillary wick creates a vapor pressure which causes (a) circulation of coolant vapor through said loop from said cold plate to said heat exchanger, and (b) circulation of liquid coolant through said loop from said heat exchanger to said cold plate, and whereby, under other conditions, said capillary wick may become deprimed, thereby impeding circulation of coolant through said loop;

said coolant coupling means further comprising a coolant pump including (a)

a coolant reservoir including an input/output port coupled to said loop at a first location between said liquid coolant output port of said heat exchanger and said liquid coolant input port of said cold plate, for, when heated, rejecting liquid coolant from said reservoir into said loop at said first location, and for, when cooled, withdrawing liquid coolant from said loop;

(b) a first check valve coupled in said loop at a second location lying between said first location and said liquid coolant input port of said cold plate, oriented for allowing flow of liquid coolant through said loop in a direction toward said cold plate, and for blocking flow of liquid coolant from said cold plate;

(c) a second check valve coupled in said loop at a third location, and oriented to allow coolant flow through said loop in said first direction; and

(d) heat control means coupled to said coolant reservoir for controllably heating and cooling said reservoir during corresponding heating and cooling cycles, for thereby rejecting liquid coolant into said loop at said first location during heating cycles whereby liquid coolant tends to be driven through said first check valve toward said cold plate, and for withdrawing liquid coolant from said loop at said first location during cooling cycles, whereby said first check valve tends to close and said second check valve to open, thereby tending to draw coolant toward said first location from said second check valve, whereby successive heating and cooling cycles tend to develop a fluid pressure which tends to pump said liquid coolant toward said cold plate, which may wet said capillary wick; and

wherein at least one of said first and second check valves is a ball-type check valve, in which the mass density of said ball equals the mass density of said coolant liquid.

4. A spacecraft according to claim 3, wherein said ball is porous, for, in a closed state, blocking the passage of liquid coolant, and allowing passage of coolant vapor.

5. A spacecraft comprising:

a payload including means for performing a desired function and in the process generating undesired heat;

a cold plate coupled to said payload for absorbing said undesired heat therefrom, said cold plate including a liquid coolant input port, a capillary wick, and a coolant vapor outlet port, for accepting liquid coolant at said liquid coolant input port, and for wetting said wick and transferring said undesired heat to said coolant for causing said wick to transform said liquid coolant into said coolant vapor;

a heat exchanger including a coolant vapor input port and a liquid coolant output port, for receiving coolant vapor at said input port and extracting heat therefrom, for thereby condensing coolant vapor arriving at said input port of said heat exchanger into liquid coolant, which becomes available at said output port of said heat exchanger;

coolant coupling means coupled in a loop to said cold plate and to said heat exchanger, for coupling said coolant vapor from said coolant vapor output port of said cold plate to said coolant vapor input port of said heat exchanger, and for coupling said liquid coolant from said liquid coolant output port of said heat exchanger to said liquid coolant input port of said cold plate, whereby, under normal conditions of said loop, said capillary wick creates a vapor pressure which causes (a) circulation of coolant vapor through said loop from said cold plate to said heat exchanger, and (b) circulation of liquid coolant through said loop from said heat exchanger to said cold plate, and whereby, under other conditions, said capillary wick may become deprimed, thereby impeding circulation of coolant through said loop;

said coolant coupling means further comprising a coolant pump including (a)

a coolant reservoir including an input/output port coupled to said loop at a first location between said liquid coolant output port of said heat exchanger and said liquid coolant input port of said cold plate, for, when heated, rejecting liquid coolant from said reservoir into said loop at said first location, and for, when cooled, withdrawing liquid coolant from said loop;

(b) a first check valve coupled in said loop at a second location lying between said first location and said liquid coolant input port of said cold plate, oriented for allowing flow of liquid coolant through said loop in a direction toward said cold plate, and for blocking flow of liquid coolant from said cold plate;

(c) a second check valve coupled in said loop at a third location, and oriented to allow coolant flow through said loop in said first direction; and

(d) heat control means coupled to said coolant reservoir for controllably heating and cooling said reservoir during corresponding heating and cooling cycles, for thereby rejecting liquid coolant into said loop at said first location during heating cycles whereby liquid coolant tends to be driven through said first check valve toward said cold plate, and for withdrawing liquid coolant from said loop at said first location during cooling cycles, whereby said first check valve tends to close and said second check valve to open, thereby tending to draw coolant toward said first location from said second check valve, whereby successive heating and cooling cycles tend to develop a fluid pressure which tends to pump said liquid coolant toward said cold plate, which may wet said capillary wick; and

wherein one of said first and second check valves is a ball-type check valve, and further including a magnet arrangement for adjusting the dead-band of said one of said first and second check valves.

7. A liquid pumping arrangement, comprising:

a source of liquid including a liquid output port;

a utilization apparatus including a liquid input port, which under some conditions may itself develop a tendency to pump;

controllable coupling means coupled to said source of liquid and to said utilization apparatus, for coupling said liquid from said source of liquid to said utilization apparatus, and controllable for pumping said liquid from said source of liquid to said utilization apparatus, said coupling means comprising;

(a) a pipe for the flow of liquid between said source of liquid and said utilization apparatus, (b) a fluid reservoir including an input/output port coupled to said pipe at a first location lying between said source of liquid and said utilization apparatus, for, when heated, rejecting liquid from said reservoir into said pipe at said first location, and for, when cooled, withdrawing liquid from said pipe;

(b) a first check valve coupled in said pipe at a second location lying between said first location and said utilization apparatus, oriented for allowing flow of said liquid through said pipe in a direction toward said utilization apparatus, and for blocking flow of liquid from said utilization apparatus toward said first location;

(c) a second check valve coupled to allow fluid flow from said source of liquid toward said first location, and to block fluid flow from said first location toward said source of liquid; and

(d) heat control means coupled to said reservoir for controllably heating and cooling said reservoir during corresponding heating and cooling cycles, for thereby rejecting liquid into said loop at said first location during heating cycles whereby liquid tends to be driven through said first check valve toward said utilization apparatus, and for withdrawing liquid from said pipe at said first location during cooling cycles, whereby said first check valve tends to close and said second check valve to open, thereby tending to draw said liquid toward said first location from said source of liquid, whereby successive heating and cooling cycles tend to develop a fluid pressure which tends to pump said liquid toward said utilization apparatus, and whereby, when said utilization apparatus pumps, said first and second check valves open to allow said liquid to flow toward said utilization apparatus;

wherein, in said liquid pumping arrangement;

said liquid is a coolant;

said utilization apparatus comprises a capillary wick which absorbs heat from a cold plate, and which, when wetted by said liquid coolant, generates coolant vapor at a coolant vapor output port which, in turn, generates said tendency to pump;

said source of liquid is a heat exchanger which includes a coolant vapor input port, and extracts heat therefrom to produce said liquid coolant; and

said coupling means comprises a path for the flow of said coolant vapor from said coolant vapor output port of said utilization means to said coolant vapor input port of said source of liquid.

8. A liquid pumping arrangement according to claim 7, wherein said second check valve is located in said pipe at a location lying between said first location and said liquid coolant output port of said source of liquid.

9. A liquid pumping arrangement according to claim 7, wherein at least one of said check valves is a ball-type check valve.

10. A liquid pumping arrangement according to claim 9, wherein said ball of said one of said ball-type check valves is porous, for, when said one of said ball-type check valves is in a closed state, allowing the flow of vapor, but not liquid, through said one of said ball-type check valves.

11. A liquid pumping arrangement, comprising:

a source of liquid including a liquid output port;

a utilization apparatus including a liquid input port, and which under some conditions may itself develop a tendency to pump;

controllable coupling means coupled to said source of liquid and to said utilization apparatus, for coupling said liquid from said source of liquid to said utilization apparatus, and controllable for pumping said liquid from said source of liquid to said utilization apparatus, said coupling means comprising;

(a) a pipe for the flow of liquid between said source of liquid and said utilization apparatus, (b) a fluid reservoir including an input/output port coupled to said pipe at a first location lying between said source of liquid and said utilization apparatus, for, when heated, rejecting liquid from said reservoir into said pipe at said first location, and for, when cooled, withdrawing liquid from said pipe;

(b) a first check valve coupled in said pipe at a second location lying between said first location and said utilization apparatus, oriented for allowing flow of said liquid through said pipe in a direction toward said utilization apparatus, and for blocking flow of liquid from said utilization apparatus toward said first location;

(c) a second check valve coupled to allow fluid flow from said source of liquid toward said first location, and to block fluid flow from said first location toward said source of liquid; and

(d) heat control means coupled to said reservoir for controllably heating and cooling said reservoir during corresponding heating and cooling cycles, for thereby rejecting liquid into said loop at said first location during heating cycles whereby liquid tends to be driven through said first check valve toward said utilization apparatus, and for withdrawing liquid from said pipe at said first location during cooling cycles, whereby said first check valve tends to close and said second check valve to open, thereby tending to draw said liquid toward said first location from said source of liquid, whereby successive heating and cooling cycles tend to develop a fluid pressure which tends to pump said liquid toward said utilization apparatus, and whereby, when said utilization apparatus pumps, said first and second check valves open to allow said liquid to flow toward said utilization apparatus; and

wherein at least one of said check valves is a ball-type check valve, and wherein said one of said ball-type check valves includes a magnet arrangement for adjusting the dead-band of said check valve.

12. A liquid pumping arrangement, comprising:

a source of liquid including a liquid output port;

a utilization apparatus including a liquid input port, and which under some conditions may itself develop a tendency to pump;

controllable coupling means coupled to said source of liquid and to said utilization apparatus, for coupling said liquid from said source of liquid to said utilization apparatus, and controllable for pumping said liquid from said source of liquid to said utilization apparatus, said coupling means comprising;

(a) a pipe for the flow of liquid between said source of liquid and said utilization apparatus, (b) a fluid reservoir including an input/output port coupled to said pipe at a first location lying between said source of liquid and said utilization apparatus, for, when heated, rejecting liquid from said reservoir into said pipe at said first location, and for, when cooled, withdrawing liquid from said pipe;

(b) a first check valve coupled in said pipe at a second location lying between said first location and said utilization apparatus, oriented for allowing flow of said liquid through said pipe in a direction toward said utilization apparatus, and for blocking flow of liquid from said utilization apparatus toward said first location;

(c) a second check valve coupled to allow fluid flow from said source of liquid toward said first location, and to block fluid flow from said first location toward said source of liquid; and

(d) heat control means coupled to said reservoir for controllably heating and cooling said reservoir during corresponding heating and cooling cycles, for thereby rejecting liquid into said loop at said first location during heating cycles whereby liquid tends to be driven through said first check valve toward said utilization apparatus, and for withdrawing liquid from said pipe at said first location during cooling cycles, whereby said first check valve tends to close and said second check valve to open, thereby tending to draw said liquid toward said first location from said source of liquid, whereby successive heating and cooling cycles tend to develop a fluid pressure which tends to pump said liquid toward said utilization apparatus, and whereby, when said utilization apparatus pumps, said first and second check valves open to allow said liquid to flow toward said utilization apparatus;

wherein;

said liquid is a coolant;

said utilization apparatus comprises a capillary wick which absorbs heat from a cold plate, and which, when wetted by said liquid coolant, generates coolant vapor at a coolant vapor output port;

said source of liquid is a heat exchanger which includes a coolant vapor input port, and extracts heat therefrom to produce said liquid coolant; and

said coupling means comprises a path for the flow of said coolant vapor from said coolant vapor output port of said utilization means to said coolant vapor input port of said source of liquid; and

further comprising

spacecraft payload apparatus coupled to said cold plate for, in association with its intended function, generating heat, which is removed by said cold plate; and

wherein

at least one of said check valves is a ball-type check valve, in which said ball has the same mass density as said coolant, whereby the action of said check valve is the same in a microgravity environment and in a gravity environment, thereby allowing testing of said liquid pumping arrangement on Earth before launch into space.

13. A liquid pumping arrangement according to claim 12, wherein said ball of said one of said ball-type check valves is porous, for, when said one of said ball-type check valves is in a closed state, allowing the flow of vapor, but not liquid, through said one of said ball-type check valves.

14. A liquid pumping arrangement according to claim 12, wherein said one of said ball-type check valves includes a magnet arrangement for adjusting the dead-band of said check valve.

15. An apparatus, comprising:

a powered unit including means for performing a desired function and in the process generating undesired heat;

a cold plate coupled to said powered unit for absorbing said undesired heat therefrom, said cold plate including a liquid coolant input port, a capillary wick, and a coolant vapor outlet port, for accepting liquid coolant at said liquid coolant input port, and for wetting said wick and transferring said undesired heat to said coolant for causing said wick to transform said liquid coolant into said coolant vapor;

a heat exchanger including a coolant vapor input port and a liquid coolant output port, for receiving coolant vapor at said input port and extracting heat therefrom, for thereby condensing coolant vapor arriving at said input port of said heat exchanger into liquid coolant, which becomes available at said output port of said heat exchanger;

coolant coupling means coupled in a loop to said cold plate and to said heat exchanger, for coupling said coolant vapor from said coolant vapor output port of said cold plate to said coolant vapor input port of said heat exchanger, and for coupling said liquid coolant from said liquid coolant output port of said heat exchanger to said liquid coolant input port of said cold plate, whereby, under normal conditions of said loop, said capillary wick creates a vapor pressure which causes (a) circulation of coolant vapor through said loop from said cold plate to said heat exchanger, and (b) circulation of liquid coolant through said loop from said heat exchanger to said cold plate, whereby said cold plate, said heat exchanger, and said coolant coupling means together constitute a capillary pump and liquid flow loop, and whereby, under other conditions, said capillary wick may become deprimed, thereby effectively disabling said capillary pump, and impeding circulation of coolant through said loop;

said coolant coupling means further comprising a further coolant pump including (a)

a coolant reservoir including an input/output port coupled to said loop at a first location between said liquid coolant output port of said heat exchanger and said liquid coolant input port of said cold plate, for, when heated, rejecting liquid coolant from said reservoir into said loop at said first location, and for, when cooled, withdrawing liquid coolant from said loop;

(b) a first check valve coupled in said loop at a second location lying between said first location and said liquid coolant input port of said cold plate, oriented for allowing flow of liquid coolant through said loop in a direction toward said cold plate, and for blocking flow of liquid coolant from said cold plate;

(c) a second check valve coupled in said loop at a third location, and oriented to allow coolant flow through said loop in said first direction; and

(d) heat control means coupled to said coolant reservoir for controllably heating and cooling said reservoir during corresponding heating and cooling cycles, for thereby rejecting liquid coolant into said loop at said first location during heating cycles whereby liquid coolant tends to be driven through said first check valve toward said cold plate, and for withdrawing liquid coolant from said loop at said first location during cooling cycles, whereby said first check valve tends to close and said second check valve to open, thereby tending to draw coolant toward said first location from said second check valve, whereby successive heating and cooling cycles tend to develop a fluid pressure which tends to pump said liquid coolant toward said cold plate, which may wet said capillary wick.