Composite heat exchanger having strengthened joints

• US 6,267,175 B1
• Filed: 02/08/2000
• Issued: 07/31/2001
• Est. Priority Date: 02/08/2000
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Anderson, Alexander F.
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): MCKINNON, TERRELL L
• Application Number:
  US09/500,250
• Time in Patent Office: 539 Days
• Field of Search: 165/164, 165/165, 165/166, 165/167, 165/146, 165/170, 165/DIG.367, 165/DIG.365, 165/DIG.387, 165/DIG.388, 165/DIG.356
• US Class Current: 165/166
• CPC Class Codes: B29C 65/02 by heating, with or without pressure
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/438 Joining sheets for making hollow-walled, channelled structures or multi-tubular articles
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/73752 the to-be-joined areas of both parts to be joined being uncured
• CPC Class Codes: B29C 66/73756 the to-be-joined areas of both parts to be joined being fully cured
• CPC Class Codes: B29C 66/73921 characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/73941 characterised by the materials of both parts being thermosets
• CPC Class Codes: B29K 2071/00 Use of polyethers , e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2077/00 Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• CPC Class Codes: B29L 2031/18 Heat-exchangers or parts thereof
• CPC Class Codes: C04B 35/83 Carbon fibres in a carbon matrix
• CPC Class Codes: F28D 9/0062 the conduits for one heat-exchange medium being formed by spaced plates with inserted elements F28D9/0012, F28D9/0025, F28D9/0081, F28D9/04 take precedence
• CPC Class Codes: F28F 21/02 of carbon, e.g. graphite
• CPC Class Codes: Y10S 165/356 Plural plates forming a stack providing flow passages therein

Abstract

A heat exchanger core includes a stack of fins, plates and closure bars. A first plurality of stiff fibers extend into contacting surfaces of the fins and plates, a second plurality of stiff fibers extend into contacting surfaces of the closure bars and plates, and a third plurality of stiff fibers extend into contacting surfaces of the closure bars and manifolds. The stiff fibers can strengthen the heat exchanger assembly and they can also increase thermal conductivity in their direction of orientation.

Claims

1. A heat exchanger comprising:

a stack of composite plates and composite members in contact with the plates, the composite members being at least one of an extended heat transfer surface and an enclosure bar; and

a plurality of stiff fibers, each fiber embedded in both a contacting plate and member of the stack.

2. The heat exchanger of claim 1, wherein the composite members include extended heat transfer surfaces.

3. The heat exchanger of claim 1, wherein the composite members include enclosure bars.

4. The heat exchanger of claim 1, wherein the fibers are roughly orthogonal to contacting surfaces of the plates and members.

5. The heat exchanger of claim 1, wherein the plates and members are made of carbon/carbon composite.

6. The heat exchanger of claim 1, wherein the plates and members are made of fabric embedded in a cured thermoplastic-type resin.

7. The heat exchanger of claim 1, wherein between at least one-quarter the length of each fiber is embedded in a plate and at least one-quarter the length of each fiber is embedded in a member.

8. The heat exchanger of claim 1, wherein the fibers have a length between {fraction (1/16)}″

and {fraction (1/32)}″

;

a diameter between 7 and 10 microns; and

a stiffness between 30 Msi and 120 Msi.

9. The heat exchanger of claim 1, wherein the fibers have a density of about 50% to 85% of contacting surface area between the plates and members.

10. An environmental control system comprising:

an air conditioning system; and

a heat exchanger upstream from the air conditioning system, the heat exchanger including a stacked assembly of plates and fins, and a plurality of stiff fibers, each fiber extending into contacting surfaces of a fin and a plate, each fiber being embedded in both a fin and a plate.

11. The system of claim 10, wherein the stacked assembly further includes a plurality of closure bars and a second plurality of stiff fibers, each fiber of the second plurality extending into contacting surfaces of a closure bar and a plate, each fiber of the second plurality being embedded in both a closure bar and a plate.

12. The system of claim 10, wherein the stacked assembly further includes a plurality of manifolds and a second plurality of stiff fibers, each fiber of the second plurality extending into contacting surfaces of a manifold and a plate, each fiber of the second plurality being embedded in both a manifold and a plate.

13. A method of fabricating a composite heat exchanger core including a plurality of plates and members, the members being selected from the group consisting of extended heat transfer surfaces and enclosure bars, each plate and member including fabric that is impregnated with resin, the method comprising:

forming a stacked core assembly of the plates and the members; and

partially inserting a plurality of stiff fibers into the plates and members while forming the stacked core assembly, each fiber extending into one of the plates and one of the members.

14. The method of claim 13, wherein the fibers are oriented prior to insertion in the plates and members.

15. The method of claim 14, wherein the fibers are oriented by polarizing the fibers, whereby the fibers are aligned in a direction of polarization.

16. The method of claim 14, wherein the fibers are oriented by inserting the fibers through a thin mesh and placing the mesh between contacting surfaces of the plates and members.

17. The method of claim 13, wherein the resin is a thermoplastic that has been cured;

wherein the plates are heated to soften the resin, the fibers are inserted in the plates, the members are heated to soften the resin, the plates and members are pressed together, and the plates and members are cooled to harden the resin.

18. The method of claim 13, wherein the resin is a thermoset, wherein the fibers are inserted into the plates and members before the plates and members have been cured, and wherein the plates and members are cured after having been pressed together.

19. The method of claim 13, further comprising attaching a manifold to the stacked core assembly;

and inserting a plurality of stiff fibers into the manifold and enclosure bars while attaching the manifold.

20. A heat exchanger comprising

a stack of composite plates and composite enclosure bars:

a composite manifold having a surface in contact with a surface of at least one of the enclosure bars; and

a plurality of stiff fibers, each fiber embedded in both the manifold and an enclosure bar in contact with the manifold.

21. A method of fabricating a heat exchanger including a plurality of composite plates, a plurality of composite enclosure bars and a manifold, each plate, member and manifold including fabric that is impregnated with resin, the method comprising:

forming a stacked core assembly of the plates and the enclosure bars;

securing the manifold to at least one of the enclosure bars; and

partially inserting a plurality of stiff fibers into the manifold and each enclosure bar making contact with the manifold, each fiber extending into the manifold and one of the contacting enclosure bars.