WO1994018516A1

WO1994018516A1 - Manifold heat exchanger

Info

Publication number: WO1994018516A1
Application number: PCT/AU1994/000039
Authority: WO
Inventors: Graeme Scott Attey; Simon John Edwards
Original assignee: Hydrocool Pty. Ltd.
Priority date: 1993-02-02
Filing date: 1994-02-01
Publication date: 1994-08-18

Abstract

A manifold comprising fluid means (30) having arrangements for increasing the velocity and/or turbulence of fluid flowing through the manifold, such as spiral members or protuberances (32, 34).

Description

TITLE MANIFOLDHEATEXCHANGER DESCRIPTION The present invention relates to a cooling apparatus. FIELD OF THE INVENTION In International Patent Application No. PCT/AU92/00008 in the names of Hyco Pty Ltd and Poseidon Scientific Instruments Pty Ltd there is described and claimed a thermoelectric system comprising a thermoelectric heat pump having first and second opposed outer faces and a manifold defining a volume attached to at least one outer face of the thermoelectric heat pump. The or each manifold has a fluid inlet and a fluid outlet so that fluid flows through to the or each manifold. The inlet and the outlet are connected to heat exchange means and fluid pump means is provided for circulating fluid between the or each manifold and the heat exchange means. The theremoelectric system of International Patent Application No. PCT/AU92/00008 is primarily intended for cooling such as refrigeration. It has now been discovered that heat transfer between the fluid and the heat exchange means in the type of manifold described in International Patent Application No. PCT/AU92/00008 can be enhanced by increasing the velocity and/or the level of turbulence in the fluid flowing through the manifold. In accordance with a first aspect of the present invention there is provided a manifold defining a volume and having an open face arranged to be juxtaposed with an article, a fluid inlet and a fluid outlet so that, in use, fluid flows through the manifold, the volume defined by the manifold including means for increasing the velocity and/or the degree of turbulence of fluid flowing through the manifold. In accordance with a second aspect of the present invention there is provided a thermoelectric cell characterised by a layer of thermocouples, a respective plastics material connector support mounted on each side of the layers, the connector support having a plurality of electrical conductor blocks mounted therein in spaced manner so as to connect up electrically P and N thermocouples. In accordance with a third aspect of the present invention there is provided a thermoelectric cell characterised by a layer of thermocouples and electrical conductor blocks disposed between adjacent pairs of P and N thermocouples. In accordance with a further aspect of the present invention there is provided a fan pump characterised by comprising a fan with a rotary blade assembly and a pump with a rotary impeller assembly, first magnet means mounted on the fan assembly, second magnet means mounted on the impeller assembly, the first and second magnet means being disposed adjacent one another, so that when the fan assembly is caused to rotate the impeller assembly is also induced to rotate by magnetic interaction between the first and second magnet means. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described, by way of example, with reference to the accompanying drawings, in which : - Figure 1 is an underneath view of a first embodiment of a manifold in accordance with the present invention; Figure 2 is a side view of the manifold of Figure 1; Figure 3 is a schematic elevation to an enlarged scale through a channel of the manifold along the line 3-3 of Figure 1 showing a fence; Figure 4 is a schematic elevation to an enlarged scale through a channel of the manifold of Figure 1 along the line 4-4 showing a gate; Figure 5 is an underneath view of a second embodiment of a manifold in accordance with the present invention; Figure 6 is an underneath view of a spiral element which can be inserted in a channel of a manifold of the present invention to increase turbulence; Figure 7 is an underneath view of an alternating spiral element which can be inserted in a channel of a manifold of the present invention to increase turbulence; Figure 8 is a side view of the manifold of Figures 1 and 2 attached to an electric circuit board; Figure 9 is a vertical sectional view of a thermoelectric module along the line B-B of Figure 10 including a new form of thermoelectric cell in accordance with the present invention; Figure 10 is a horizontal sectional view of the thermoelectric module of Figure 9 along the line A-A of Figure 9; Figure 11 is a side elevation of a further form of thermoelectric module in accordance with the present invention; and Figure 12 is a side elevation of a fan pump in accordance with the present invention. In, figαres 1 to 4 of the drawings there is shown a manifold 10 comprising a volume defining housing 12. The housing 12 comprises a rectangular peripheral side wall 14 and a rear wall 16. Further, the housing 12 has an open front face 18. Further, the housing 12 includes a fluid inlet tube 20 and a fluid outlet tube 22 both mounted to the side wall 14. Within the housing 12 the manifold includes a plurality of parallel partitions 24 which extend generally at about right angles to the fluid inlet 20 and the fluid outlet 22 and are of substantially the same length as one another. Further, the partitions 24 extend generally in depth from an inner face of the rear wall 16 to the open face 18. In terms of length each partition 24 extends from a point aligned with the inlet 20 to a point aligned with the outlet 22. However, in length the partitions 24 do not extend as far as the side wall 14 so that at the ends thereof adjacent the inlet tube 20 there is a lateral inlet channel 26 and at the ends thereof adjacent the outlet 22 there is a lateral outlet channel 28. Interconnecting the channels 26 and 28 there is a plurality of laterally extending straight parallel channels 30 defined by the partitions 24. The channels 30 include turbulence enhancing features such as small protruberances fitting into the path of the fluid in the channels 30. The protruberances can be in the form of gates 32 (see Figure 4) which preferably extend alternately from opposite sides of the channels 30 partially across the channels 30. Further, the protruberances can take form of fences 34 depending from the inner face of the wall 16 into the channels 30 for a part of the depth thereof. This arrangement creates a turbulent fluid flow through each of the channels 30 with relatively low fluid impedance compared to a zig-zag series channel arrangement as described in International Patent Application No. PCT/AU92/00008. Thus, with the arrangements shown in Figures 1 to 4, the pump power required to pump fluid from the inlet 20 to the outlet 22 is reduced compared to the prior art. Typically, in a manifold having a width of about 40 mm the number of channels 30 would be in the range from 8 to 30. An alternative embodiment of manifold in accordance with the present invention is illustrated figure 5. In this embodiment there is shown a manifold 40 having a rectangular peripheral side wall 42 and a rear wall 44. The manifold 40 also has an open face 46. The manifold 40 includes a longitudinal partition 48 which effectively divides the manifold 40 into two parallel channels 50 and 52. The manifold 40 includes an inlet 54 for the channel 50 and an inlet 56 for the channel 52. Further, the manifold 40 includes an outlet 58 for the channel 50 and outlet 60 for the channel 52. Each channel 50 and 52 includes a plurality of partitions 62 extending in depth from an inner face of the rear wall 44 to the open face 46. As can be seen in figure 5 the partitions 62 extend alternately from the side wall 42 and the partition 48 but always stop short of the opposing wall or. partition so that there is defined in each channel 50 and 52 a single, fluid series zig-zag channel 64 formed by the partitions 62 extending from each inlet 54 and 56 to the respective outlet 58 and 60. The use of more than one zig-zag path in a single manifold increases turbulence in fluid flowing through the manifold because of the large number u-turns that the fluid has to pass through whilst reducing fluid impedance compared to the use of a single series. Further, in order to ensure that the fluid has sufficient velocity, each channel 50 and 52 contains more than 8 partitions 62 and in fact has eleven partitions 62 in the illustrated embodiment. In Figure 6, there is shown an underneath view of a spiral element 63 which can be inserted in a channel 30 or 64 to increase turbulence of fluid flowing through a manifold in accordance with the present invention. In Figure 7, there is shown an underneath view of an alternating spiral element which can be inserted in a channel 30 or 64 to increase the turbulence of fluid flowing through a manifold in accordance with the present invention. The manifolds of the present invention may be attached to thermoelectric modules and be used as a heat transfer means in the manner described in International Patent Application No. PCT/AU92/0008. In addition, the manifolds of the present invention can be attached to electronic components in conjunction with a pump and a heat exchanger as described in International Patent No. PCT/AU92/00008, so as to dissipate heat generated during operation of the electronic component. The type of electronic component to which the present invention may be applied include radio frequency power amplifiers, transistors and transmitters, and printed circuit boards. If it were desired to cool the electronic component below ambient temperature then the manifold would be used in conjunction with a thermoelectric cell. However, if it is merely desired to cool the electronic component to a temperature not below ambient temperature then the manifold can be used without the thermoelectric cell as shown in Figure 8. Typically, a manifold in accordance with the present invention such as a manifold 10 is attached at a point where heat is produced so that the manifold can remove heat from the component. The fluid from the manifold containing heat is pumped to a heat exchanger at which the heat is dissipated and the cool fluid is returned to the manifold so that a continuous cycle is established. The manifold of the present invention can be placed directly on the electronic component or onto a heat conductive plate which may be made of aluminium or copper,attached to the electronic component. In Figure 8 there is shown a manifold 10 attached to a back plate 65 of an electronic component 66. In Figures 9 and 10 there is shown a thermoelectric assembly 70 in accordance with the present invention comprising a layer of P thermocouples 72 and N thermocouples 74. Mounted on each side of the layer of thermocouples is a respective moulded plastic material connector support 76 having a plurality of electrical conductor blocks 78 mounted in spaced manner in an array in the plastic material (as shown in Figure 10) so as to connect up electrically the P and N thermocouples. The connector blocks 78 may be made of copper or silver and extend right through the plastic material. The blocks 78 are held in place by engagement with the plastic material located around their sides. The blocks 78 are moulded in situ when the plastic material is moulded and the plastic material seals around the edges of the blocks 78 so as to make a fluid tight connection between the plastic material and the blocks 78. The moulding technique ensures that the blocks 78 are located in the precise location required for soldering to the thermocouple 72 and 74. The blocks 78 are relatively large compared with conventional connectors. As can be seen in Figure 10 the connector blocks 78 project rearwardly of the plastic material support 76. Thus, when the assembly shown in Figures 9 and 10 is used in conjunction with a manifold of the type described in International Patent Application No PCT/AU92/00008 and of the type described herein the rearward projection of the blocks 78 provides large surface areas in contact with fluid flowing through the manifolds for efficient heat transfer. The front faces of the connector blocks 78 are flush with the face of the support 76 adjacent the layer of the thermocouples 72 and 74 for good electrical connection. It is found that the plastic material is cheaper than conventional ceramics, is easier to work with and is more efficient because there is a reduction in convection losses from the hot to the cold side of the assembly. Further, the plastics material manifold can be welded correctly to the support 76 which ensures a fluid tight bond and negates the need for bolts and the like to apply pressure between the manifold and the support 76. Preferably, the supports 76 also include small caps which extend down and around top sections of the P and N thermocouples 72 and 74 to increase the thermal isolation of the hottest and coldest parts of the thermocouples, and thereby reduce convection losses. Also, a thin reflective layer could be placed parallel to the supports 76 and halfway between them extending through and around the array of thermocouples 72 and 74 so as to further reduce convection and also radiation losses from the hot to the cold side. Further, as can be seen in Figure 10, there may be provided plastic material bridging pieces 80 between the corners of adjacent blocks 78. The pieces 80 cause there to be discrete flow paths for fluid through the manifolds from the inlet to the outlet. The pieces 80 may be moulded integrally with the supports 76. In Figure 11 there is shown a modified form of thermoelectric module which is an improvement of that shown in Figures 8 and 9 of International Patent Application No. PCT/AU92/00008. In the embodiment shown in Figure 11, there is a layer of thermocouples comprising P thermocouples 90 and N thermocouples 92. Further, there are electrically conductive blocks 93, which may be made of copper disposed between adjacent P and N thermocouples and extending rearwardly thereof into manifolds 94 of the general type described herein and in International Patent Application NO. PCT/AU92/00008. The blocks 93 extend right across the manifolds 94 as shown in Figure 11, whilst still permitting fluid flow so as to provide large heat transfer surfaces with the manifolds 94 The arrangement shown in Figure 11 is easier to construct and is structurally stronger than the arrangement shown in Figures 8 and 9 of International Patent Application NO. PCT/AU92/00008, because the blocks 93 have leading ends disposed between adjacent P and N thermocouples 90 and 92. In Figure 12, there is shown a fan pump 100 in which a fan 102 is used to operate a pump 104 by means of a magnetic coupling. This is particularly useful in the context of the present invention which requires both pumps and fans for circulation of fluid and for cooling. The fan 102 includes a shaft 106 and a hub 108 rotatably mounted thereon. Fan blades 110 extend radially outward from the hub 108. Attached to the rear of the hub 108 is a number of magnets 112. The pump 104 includes a rotatable impeller 114 mounted within a housing 116 having an inlet 118 and an outlet 120. The housing 116 is closed adjacent the fan 102 so there is no physical connection between the fan 102 and the pump 104 except at mounting points around the perimeter of the fan housing 124. A number of magnets 122 are mounted to the impeller 114 in opposition to the magnets 112 on the fan 102. When the fan 102 rotates, the magnets 112 also rotate and this induces a corresponding rotation in the magnets 122. Thus, the impeller 114 is caused to rotate. This causes fluid to be moved from the inlet 118 to the outlet 120 in the pump housing 116. Thus, there is no requirement for a separate motor to drive the pump 104. With the thermoelectric module of the present invention and International Patent Application No. PCT/AU92/00008, it is envisaged that a solar panel could be used that produces enough power to power a refrigerator directly during sunlight hours only. The power output of the solar panel would be matched to the power consumption of the refrigerator. The solar panel would typically only be arranged to power the refrigerator during daylight hours so that there would be no need to provide a battery and the solar panel could be smaller than one designed to power the refrigerator 24 hours a day. Thus, the provision of the solar panel could be achieved economically with a significant reduction in main power consumption. Modifications and variations such as would be apparent to a skilled addressee are deemed within the scope of the present invention.

Claims

CLAIMS 1. A manifold characterised by defining a volume and having an open face arranged to be juxtaposed with an article, a fluid inlet and a fluid outlet so that, in use, fluid flows through the manifold, the volume defined by the manifold including means for increasing the heat transfer between the fluid and the juxtaposed article by increasing the velocity and/or the degree of turbulence of fluid flowing through the manifold. 2. A manifold according to claim 1, characterised in that the manifold includes two or more parallel flow channels. 3. A manifold according to claim 2, characterised in that at least some of the flow channels have incorporated therebetween protuberances to increase turbulence of fluid flowing through the manifold. 4. A manifold according to claim 3, characterised in that the protuberances are in the form of gates extending partially across a channel and/or fences extending across a channel for part of the depth of a channel. 5. A manifold according to claim 2, characterised in that the flow channels define zig-zag flow paths. 6. A manifold according to any one of claims 2 to 5, characterised in that at least some of the flow channels contain spiral members for increasing the turbulence of fluid flowing through the manifold. 7. A thermoelectric cell characterised by a layer of thermocouples, a respective plastics material connector support mounted on each side of the layers, the connector support having a plurality of electrical conductor blocks mounted therein in spaced manner so as to connect up electrically P and N thermocouples. 8. A thermoelectric cell according to claim 7, characterised in that the plastics material connector support is moulded. 9. A thermoelectric cell according to claim 8, in that the conductor blocks are moulded in situ into the connector support. 10. A thermoelectric cell according to any one of claims 7 to 9, characterised in that the conductor blocks project rearwardly of the connector support. 11. A thermoelectric cell characterised by a layer of thermocouples and electrical conductor blocks disposed between adjacent pairs of P and N thermocouples. 12. A fan pump characterised by comprising a fan with a rotary blade assembly and a pump with a rotary impeller assembly, first magnet means mounted on the fan assembly, second magnet means mounted on the impeller assembly, the first and second magnet means being disposed adjacent one another, so that when the fan assembly is caused to rotate the impeller assembly is also induced to rotate by magnetic interaction between the first and second magnet means.