Thermoelectric assembly sealing member with metal vapor barrier

Abstract

A thermoelectric assembly includes a thermoelectric module having a hot side and a cold side, where a heat sink is coupled with the hot side of the thermoelectric module and a cold sink is coupled with the cold side of the thermoelectric module. A metalized gasket is disposed between the heat sink and the cold sink and extends around a portion of the thermoelectric module. A vapor barrier may be attached to and cover an outer surface of the metalized gasket.

Claims

1. A thermoelectric assembly comprising: a thermoelectric module having a hot side and a cold side; a heat sink coupled with the hot side of the thermoelectric module; a cold sink coupled with the cold side of the thermoelectric module; and a metalized gasket member comprising a first interfacing surface coupled with the heat sink and a second interfacing surface coupled with the cold sink, wherein the metalized gasket member comprises an opening that extends between the first and second interfacing surfaces and that provides an interior space that surrounds a periphery of the thermoelectric module, and wherein at least one of an exterior peripheral surface or an interior peripheral surface of the metalized gasket member that extends between the first and second interfacing surfaces around the metalized gasket member is configured to prevent water vapor from penetrating into the interior space surrounded by the metalized gasket member.

2. The thermoelectric assembly of claim 1, wherein the metalized gasket member comprises a gasket with a metalized surface, and wherein the metalized surface comprises an external peripheral surface and/or an internal peripheral surface of the gasket and that extends between the heat sink and the cold sink.

3. The thermoelectric assembly of claim 1, wherein seals are disposed between the first and second interfacing surfaces of the metalized gasket member and the heat sink and cold sink, respectively.

4. The thermoelectric assembly of claim 1, wherein the metalized gasket member comprises a substantially rigid single piece of metal or metallized plastic configured to remain in place between the heat sink and the cold sink without an additional interior gasket.

5. The thermoelectric assembly of claim 1, wherein the metalized gasket comprises flanges disposed at the first interfacing surface and the second interfacing surface, and comprises a sidewall extending between the flanges.

6. The thermoelectric assembly of claim 5, wherein the flanges extend perpendicularly relative to the sidewall and parallel with the heat sink and the cold sink.

7. The thermoelectric assembly of claim 6, wherein the flange at the first interfacing surface forms a T-shape or an L-shape with respect to the sidewall, and wherein the flange at the second interfacing surface forms a T-shape or an L-shape with respect to the sidewall.

8. The thermoelectric assembly of claim 1, wherein the metalized gasket member comprises a metallized plastic material.

9. The thermoelectric assembly of claim 8, wherein the metalized gasket comprises a plastic core with a metalized surface.

10. The thermoelectric assembly of claim 9, wherein the metalized surface comprises an outer external peripheral surface.

11. The thermoelectric assembly of claim 9, wherein the metalized gasket member comprises an internal peripheral surface.

12. The thermoelectric assembly of claim 1, wherein the metalized gasket member comprises a substantially rigid single piece of metalized material.

13. A thermoelectric assembly comprising: a thermoelectric module having a hot side and a cold side; a heat sink coupled with the hot side of the thermoelectric module; a cold sink coupled with the cold side of the thermoelectric module; and a metalized gasket comprising a first interfacing surface coupled with the heat sink and a second interfacing surface coupled with the cold sink, wherein the metalized gasket comprises an opening that extends between the first and second interfacing surfaces and that provides an interior space that surrounds a periphery of the thermoelectric module, and wherein at least one of an exterior peripheral surface or an interior peripheral surface of the metalized gasket that extends between the first and second interfacing surfaces around the metalized gasket is configured to prevent water vapor from penetrating into the interior space surrounded by the metalized gasket, and wherein the metalized gasket comprises a substantially rigid single piece material.

14. The thermoelectric assembly of claim 13, wherein the metalized gasket member comprises a gasket with a metalized surface, and wherein the metalized surface comprises an external peripheral surface and/or an internal peripheral surface of the gasket and that extends between the heat sink and the cold sink.

15. The thermoelectric assembly of claim 13, wherein seals are disposed between the first and second interfacing surfaces of the metalized gasket member and the heat sink and cold sink, respectively.

16. The thermoelectric assembly of claim 13, wherein the metalized gasket comprises flanges disposed at the first interfacing surface and the second interfacing surface, and comprises a sidewall extending between the flanges.

17. The thermoelectric assembly of claim 16, wherein the flanges extend perpendicularly relative to the sidewall and parallel with the heat sink and the cold sink.

18. The thermoelectric assembly of claim 17, wherein the flange at the first interfacing surface forms a T-shape or an L-shape with respect to the sidewall, and wherein the flange at the second interfacing surface forms a T-shape or an L-shape with respect to the sidewall.

19. The thermoelectric assembly of claim 13, wherein the metalized gasket member comprises a metallized plastic material.

20. The thermoelectric assembly of claim 19, wherein the metalized gasket comprises a plastic core with a metalized surface, and wherein the metalized surface comprises an outer external peripheral surface and/or an internal peripheral surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an upper perspective view of a thermoelectric assembly having a metal vapor barrier, in accordance with the present invention;

(2) FIG. 2 is an exploded upper perspective view of the thermoelectric assembly having the metal vapor barrier shown in FIG. 1;

(3) FIG. 3 is a cross-sectional view of the thermoelectric assembly taken at section 3-3 shown in FIG. 1; and

(4) FIG. 4 is a partial cross-sectional view of a thermoelectric assembly having an alternative metal vapor barrier in accordance with another aspect of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) Referring now to the drawings and the illustrative embodiments depicted therein, a thermoelectric assembly 10 includes two thermoelectric modules 12 (FIGS. 2 and 3) that each have a hot surface or side 14 and, on the opposing side, a cold surface or side 16. A contact surface 18a of a heat exchanger or heat sink 18 is in contact with the hot side 14 of each of the thermoelectric modules 12 and a contact surface 20a of another heat exchanger or a cold plate or sink 20 is in contact with the cold side 16 of each of the thermoelectric modules 12. The opposing side of heat sink 18 from the thermoelectric modules 12 is coupled to an exhaust fan 22. A sealing member 24 surrounds and seals the thermoelectric modules 12. The sealing member 24 includes an insulation vapor seal or gasket 26 that is disposed between the heat sink 18 and the cold sink 20 and extends around each of the thermoelectric modules 12. A metal or metallic vapor barrier 28 is attached and covers an outer surface 26a of the gasket 26 to prevent water vapor from penetrating the outer surface 26a of the gasket 26. In operation, the cold plate or sink 20 can be in contact (directly or indirectly) with an object or medium which is to be cooled. As the cold sink 20 performs the cooling function, the thermoelectric module 12 thermoelectrically absorbs heat therefrom and transfers the same to the heat sink 18, which is subsequently exhausted to the environment by the exhaust fan 22.

(6) It will be recognized that although two thermoelectric modules 12 are illustrated in the drawings, a single thermoelectric module or additional modules may be provided, and one sealing member or multiple sealing members may be used depending on the arrangement. Also, the illustrated thermoelectric modules 12 may be any thermoelectric module normally employed in thermoelectric assemblies. It is also recognized that the illustrated thermoelectric assembly 10 is one form, specifically, a plate-to-air thermoelectric assembly, and shall not be limiting of the invention. The present invention is also applicable to plate-to-plate thermoelectric assemblies, air-to-air thermoelectric assemblies, or liquid-to-air thermoelectric assemblies and all possible combinations of the like. Thus, it will be understood, that the present invention may be used in conjunction with any form of thermoelectric assembly.

(7) As shown in FIG. 1, the sealing member 24 is positioned in sealing contact with a surface of the heat sink, such as with the contact surface 18a of the heat sink 18, and in sealing contact with a surface of the cold sink, such as surface 20b (FIGS. 2 and 3) that surrounds the contact surface 20a of cold sink 20. The sealing member 24 provides a generally hermetic seal, to inhibit or prevent water vapor from entering the interior area 30 (FIG. 2) within sealing member 24 and condensing on either of the thermoelectric modules 12 which could otherwise cause premature degradation thereof. The illustrated sealing member 24 includes the gasket 26 disposed between the heat sink 18 and the cold sink 20 and extends around a peripheral portion of each of the thermoelectric modules 12 (FIG. 2) that separates the hot and cold sides 14, 16 of the thermoelectric modules 12. As such, a space 30a (FIG. 3) may be formed between the inner surface 26b of the gasket 26 and the peripheral portions of the thermoelectric modules 12. This space 30a may be left as an air barrier, or during assembly may be filled with an insulating filler material, a desiccant, and/or purged with a dry gas.

(8) The outer surface 26a of the gasket 26, as shown in FIG. 2, extends between the heat sink 18 and the cold sink 20 to define an exterior perimeter surface 26a of the gasket 26 (FIG. 2). In the illustrated embodiment the exterior perimeter surface or outer surface 26a is shown as being perpendicular to the surfaces 18a and 20b. The vapor barrier 28 of the sealing member 24 is attached to and substantially covers the outer surface 26a of the gasket 26 between the heat sink 18 and the cold sink 20 to prevent water vapor from penetrating into and through the outer surface 26a. The vapor barrier 28 is a metallic vapor barrier that may comprise at least one of a metalized film, a metal foil, a stainless steel foil, or other thin and preferably metal material or the like. This may include, for example, metalized plastic films, such as Mylar or other metallized plastic or polyester, as well as metalized plastic films used in the packing industry, such as in the food packaging industry. The foil is useful as its water vapor permeability is not temperature dependent like a polymer, and also foil can be applied to generally any type of gasket and can be used without a gasket backing. The material of the vapor barrier 28 is selected to have a low thermal conductivity (such as stainless steel) and/or to be thin to reduce, inhibit or otherwise prevent a thermal conduction path from the heat sink 18 to the cold sink 20. By way of example, the metallic vapor barrier 28 may be constructed of a metallic material having a low conductivity in the low range of approximately 2.6 W/m.Math.K, such as may be provided by a heat resistant stainless steel alloy, or may be constructed of a metallic material having a higher conductivity up to approximately 250 W/m.Math.K, such as may be provided by pure aluminum. It should be appreciated, however, that utilization of a metallic material having a higher conductivity would additionally necessitate constructing the metallic vapor barrier 28 to be thin to resist heat transfer between the heat sink 18 and cold sink 20. For example, the metallic vapor barrier 28 may be formed by a sputter process, such as on a plastic layer, to have a metallic thickness in the range of 5 to 10 nm. Alternatively, utilization of a metallic material having a lower conductivity may allow or enable use of a thicker vapor barrier 28, such as having a thickness of approximately 10 mm if a rigid structure is desired, as discussed in connection with FIG. 4 below. Thus, the vapor barrier 28 may be configured to be sufficiently thick enough to retain the necessary barrier properties. For example, it is conceivable that a metal material of the vapor barrier 28 may be welded, such as by laser welding, to at least one of the heat sink and the cold sink to adhere and prevent water from getting in between vapor barrier 28 and the gasket 26. In testing, the vapor barrier 28 performed with surprising result to reduce the amount of water entering the exchanger by about seven times.

(9) The illustrated vapor barrier 28 includes four separate pieces that are separately adhered to the outer surface 26a of the gasket 26 with a pieces of sealant or adhesive 34. Also, sealant or adhesive can be used to cover top and bottom ends or edges 28a, 28b of the vapor barrier 28 along the interface 29 (FIG. 1) with the heat sink 18 and cold sink 20 to prevent water from getting in between the vapor barrier 28 and the gasket 26. Further, the interface seams 29 (FIG. 1) between the gasket 26 and the heat sink 18 and/or the cold sink 20 may be covered with an extension of the vapor barrier 28, with seals disposed between the gasket 26 and the heat sink 18 and/or the cold sink 20, such as a sealant or adhesive 34 to further reduce water vapor and other gas permeation into the completed cooling assembly. As such, the pieces of sealant or adhesive 34 can be selected to be an additional vapor barrier that is disposed between the metalized foil or film layer and the gasket. For example, foil may be sealed against heat exchanger surfaces using various sealants, such as Butyl rubber, polyisobutylene rubber, polyurethane and polysulfide sealants, sealants used in the insulated glass industry, or through other techniques, such as but not limited to Silicone rubbers (RTV), epoxies, and acrylic adhesives. This same sealant may be used as a seal between the gasket 26 and the heat sink 18 and/or the cold sink 20. Alternatively, o-rings, or other gaskets, such as elastomeric materials, may be used as seals between the gasket 26 and the heat sink 18 and/or the cold sink 20.

(10) Optionally, the vapor barrier 28 may include an exterior protective coating, such as a film, tape, adhesive, sealant, and/or other cover, which may be applied to or disposed over an exterior surface of the metalized foil or film layer. The exterior coating may function to prevent damage to the foil and/or gasket when handling the completed cooling assembly. Similarly, additional layers of vapor barrier can be placed over the foil or film of the vapor barrier to overlap the seams between the heat exchanger surfaces and/or other seams in the foil. Such additional layer or layers may comprise four separate layers positioned at the four sides of the interface seams 29 between the four exposed surfaces 26a and the heat sink 18 and an additional four separate layers positioned at the four interface seams between the four exposed surfaces 26a and the cold sink 20. Still further, the vapor barrier 28 may be configured to have multiple layers disposed over or about the entire gasket 26.

(11) It is contemplated that the metallic vapor barrier 28 may alternatively comprise more or fewer pieces, such as a single piece of material, such as film or foil, which can be wrapped completely around the gasket and potentially overlapped in areas, such as at any seams, to promote a better vapor barrier. Also, a foil or metalized film can extend onto and cover portions of the surfaces of the heat sink 18 or cold sink 20 to promote better sealing. Similarly, the vapor barrier 28 may comprise a metallized layer of shrink-wrappable barrier material, such as metalized film, that is heat wrapped, suction wrapped, or otherwise shrink wrapped to the gasket for ease of application. Further, it is contemplated that the vapor barrier may be a one piece stamped or otherwise manufactured enclosure, such as forming a 4-sided box shape, with optional sealing flanges integrated into the shape of the vapor barrier and/or the heat exchanger mating or contact surfaces. For example, the heat sink and/or the cold sink may include a sealing flange integrated with and protruding around the gasket to engage an edge portion of the vapor barrier.

(12) As also shown in FIGS. 2 and 3, the wires 32 that power or operate the thermoelectric modules 12 are illustrated entering the peripheral portion of each of the thermoelectric modules 12. As such, the wires 32 can go through or around the vapor barrier 28, such as through seams of the pieces of the vapor barrier 28 or can go through apertures in the hot or cold sinks 18, 20. If the wires 32 pass through or around the vapor barrier 28, the wires may include sealant around the point of passing through or around the vapor barrier 28. Similarly, if the wires 32 extend to the modules 12 through holes in heat sink 18 or cold sink 20, the holes may also be sealed with sealant or with other means, such as wire feedthroughs and hermetic feedthroughs. Sealing around wires 32 may be further enhanced by using solid, non-stranded wire.

(13) The gasket 26 of the sealing member 24 is illustrated in FIG. 2 having fastener holes 36 that allow screws or bolts 38 or the like to engage between the heat sink 18 and the cold sink 20, such as to compress the gasket 26. It is contemplated that assembly screws can alternatively be placed outside the gasket for improved sealing of assembly. The gasket 26 has a continuous, closed shape that is generally rectangular in the illustrated embodiment, but may have arcuate or curved corners, or even be generally circular or elliptical, to avoid the presence of hard angles which can compromise the ability of sealing member to provide a hermetic seal. A rounded, circular, or elliptical gasket may promote the use of a single vapor barrier disposed about the gasket exterior to reduce the number of pieces or avoid the use of multiple pieces of vapor barrier. It will be understood by those with ordinary skill in the art that although depicted with a rectangular shape, the gasket 26 and corresponding sealing member 24 may assume any shape required by the particular application. For example, depending upon the peripheral dimension of thermoelectric module 12, the gasket 26 may assume a generally circular or oval shape. Further, it will be understood that sealing member 24 may be made to assume any size required by the particular thermoelectric module 20 which is to be sealed.

(14) The gasket 26 may comprise a foam material or other known insulating material, such as a porous and/or non-metallic material. For example, the gasket 26 may be formed in place on the surface of one of the heat exchanger, heat sink or cold sink plates by dispensing sealing or gasket material from a suitable dispensing apparatus or machine in a suitable closed, continuous shape extending around the entirety of one or more thermoelectric modules to be hermetically sealed. Similarly, the gasket 26 may be extruded into a desired shape for use in a thermoelectric assembly as described herein. Other known gaskets and associated thermoelectric assemblies are described in U.S. Pat. Nos. 6,530,231 and 6,662,571, which are hereby incorporated herein by reference in their entireties.

(15) Optionally, with reference to the embodiment of FIG. 4, a thermoelectric assembly may include a metalized gasket member 40 that can act as the vapor barrier and replace a separate gasket, such as replacing the separate foam gasket 26, between the heat sink 18 and the cold sink 20. Similar in shape to an internal gasket, the metalized gasket member 40 would also include an opening that extends between the first and second interfacing surfaces and that provides an interior space 30a that is configured to surround a periphery of the thermoelectric module. Such a metalized gasket member 40 has sufficient mechanical strength and rigidity, either alone or with a ridged backing support, such as a rigid plastic member, to remain fixed in place and be self-supporting when installed and inhibit damage during handling, transportation and operation, as well as withstand any partial compressive forces that may be applied thereto when mounting between the heat sink 18 and the cold sink 40. The metalized gasket member 40 may have either one or both of an exterior peripheral metalized surface 42 extending between the first and second interface surfaces and/or an interior peripheral metalized surface 44 extending between the first and second interface surfaces, where the interior peripheral surface would be directed toward and surround the thermoelectric modules 12. For example, the metalized gasket may comprise a core material, such as a plastic, with an exterior metalized surface 42 and/or an interior metalized surface 44.

(16) Thus, the metalized gasket member 40 has a first interfacing surface 46 that is configured to engage and seal against the heat sink 18 and a second interfacing surface 48 that is configured to engage and seal against the cold sink 20. The engagement at the first and second interfacing surfaces 46, 48 may be provided with a seal 49, where the seal 49 may be configured as a sealant, preferably one of low water vapor permeability, to prevent water vapor from penetrating into the interior space 30a surrounded by the gasket 40, and/or alternatively may be provided as an o-ring or other gasket. The metalized gasket member 40 may include or comprise a single piece of metal or metallized plastic that has a sufficient mechanical strength to replace or avoid use of a separate gasket. In the case of a single piece of metal, the metalized gasket member may be stamped from a piece of metal. In the case of a single piece of metallized plastic, the metalized gasket member may be vacuum formed or molded plastic. Such a metalized gasket member may further include an extended interface seam or sealing flange 50, such as an L-shaped or T-shaped flange relative to the sidewall of gasket 40, at both the heat sink and cold sink interfaces, which would improve the sealing between the heat sink and/or cold sink. The flange thus comprises one or more legs extending generally parallel with the surfaces of the heat sink 18 and cold sink 20 and generally perpendicular to the sidewall of the gasket 40.

(17) In the illustrated embodiment the metallic vapor barrier is disposed only about the perimeter of the gasket, or formed therewith, and disposed between the cold sink and heat sink of the assembly to thereby inhibit the amount of water vapor or other liquid condensation that may penetrate or permeate through or around the gasket. It should be appreciated that the water vapor permeability of the metal or metalized vapor barrier is generally zero, but that depending on the thickness thereof may have microscopic pinholes or cracks.

(18) Changes and modifications in the specifically-described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law including the doctrine of equivalents.