Capillary evaporator

• US 6,241,008 B1
• Filed: 04/16/1997
• Issued: 06/05/2001
• Est. Priority Date: 05/03/1996
• Status: Expired due to Fees

• Current Assignee: Eads Astrium Ltd. (Airbus SE)
• Original Assignee: Matra Marconi Space UK Limited
• Inventors: Dunbar, Neil William
• Primary Examiner(s): ATKINSON, CHRISTOPHER MARK
• Application Number:
  US08/843,439
• Time in Patent Office: 1,511 Days
• Field of Search: 165/104.26, 165/80.3, 165/905, 165/185, 165/907, 165/41, 126/45, 126/96, 361/700, 257/715, 174/15.2
• US Class Current: 165/104.26
• CPC Class Codes: F28D 15/043 forming loops, e.g. capillary pumped loops
• CPC Class Codes: Y10S 165/905 Materials of manufacture
• CPC Class Codes: Y10S 165/907 Porous

Abstract

In a capillary evaporator for use in a capillary pumped loop, in which capillary action in a porous wick 7 causes cold liquid to be drawn across the wick and vaporized by a heat input structure 6 and in particular fin 8 of that structure so that the vapour passes around a loop and rejects heat at a condenser in order to cool equipment in the vicinity of the evaporator, the vapour generated in the wick 7 from the liquid/vapor interface (meniscus) 11 is subject to a lower pressure drop than hitherto by virtue of a spacer 14 of greater permeability and thermal conductivity than the wick 7 without the necessity for the meniscus 11 to recede from the fin 8 which would cause an undesirable temperature drop of the meniscus, thereby improving the capacity of the evaporator to pump liquid/vapor around the loop and thus transport heat.

Claims

1. A capillary evaporator comprising an inlet and an outlet for communication with a loop containing a working fluid, a wick for drawing in by capillary action working fluid in liquid form received from the inlet, and a heat input structure for vaporizing said working fluid in the wick for passage through the outlet, in which there is provided a conductive spacer for spacing the input structure from the wick, the spacer having a greater thermal conductivity than the wick, and producing a lower pressure drop per unit length for a given cross sectional area, for a given vapor, than the wick and the spacer having a higher permeability than the wick.

2. A capillary evaporator as claimed in claim 1, in which the spacer produces less than one tenth of the pressure drop per unit length for a given cross-sectional area, for a given vapor, than the wick.

3. A capillary evaporator is claimed in claim 2, in which the spacer produces less than one hundredth of the pressure drop per unit length for a given cross-sectional area, for a given vapor than the wick.

4. A capillary evaporator as claimed in claim 1, in which the wick is a plastics or ceramic material.

5. A capillary evaporator as claimed in claim 1, in which the spacer is nickel or aluminum.

6. A capillary pumped loop which includes a capillary evaporator as claimed in claim 1.

7. A satellite which includes a capillary pumped loop as claimed in claim 6 for heat transport.