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(11) | EP 0 183 007 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Port bushings for internally manifolded stacked, finned-plate heat exchanger |
| (57) Internal plates 10, 11, 12 for a finned-plate, plate stack heat exchanger 50 are
formed with manifold areas 32, 33 one at each opposite end. Ports 22, 24, 26, 28 are
excised through each plate in the manifold areas, two ports at each end. A pair of
compressible, fluid-impervious bushings 34 are inserted in two diagonally opposed
ports, e.g. 22, 28 or 24, 26, in each plate and extend upwards to make fluid-impervious
contact with the bottom surface of the plate immediately above. Thus, fluid can flow
through the bushings between a first and a third plate without leaking onto the second
plate which is located between the first and third plates. The interior plates 10,
11 and 12 of the exchanger 50 are rotatable 180° without altering the mating orientation
of the ports of any two adjacent interior plates, e.g.. 10 and 12. |
Background of the Invention
1. Field of the Invention
[0001] This invention relates to plate-stack heat exchangers and especially to plate-stack heat exchangers with internal manifolding.
2. Description of the Prior Art
[0002] Finned-plate heat exchangers are mainly of the channel and rib-type construction. Countercurrent flow can be achieved; however, manifolding a plate stack which must separate the fluids at entry and exit becomes extremely complex. Since the manifolding of the crosscurrent heat exchangers is comparatively simple, this heat exchanger system is more widely used although it is less efficient than the countercurrent system and it induces serious thermal and mechanical stresses.
[0003] One crosscurrent system which has attempted to solve the manifolding problem of the countercurrent heat exchanger is taught by Campbell et al, U.S. Patent No. 3,305,010. Campbell et al teach a heat exchanger having superposed stacked plate and fin elements and complex manifolding means for introducing fluids of different temperatures into opposite ends of the assembly. However. Campbell et al do not teach a plate which serves as both the plate and the fin, nor does Campbell et al teach means for internally manifolding the plate within the plate's plane.
[0004] One of the problems in the stacked plate type of heat exchanger is the blocking of a selected internal port at any stack level to prevent fluid flow from the selected port through the channels on that level and, thus, to force the fluid through the port to the next level where it is permitted to flow through the channels.
Obiects of the Invention
[0005] An object of the present invention is to provide a finned plate for an internally manifolded plate-stack heat exchanger.
[0006] Another object is to provide a simple means for blocking the flow from a fluid-inlet port at a given plate level in a plate-stack heat exchanger and for passing that fluid through to a fluid-inlet port in the next higher plate.
[0007] Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered 1n conjunction with the accompanying drawing.
Summary of the Invention
[0008] The invention comprises an internally manifolded, countercurrent, finned-plate- stack heat exchanger, each interior plate having manifold areas at opposite ends thereof. Flow, or fluid entry, ports are excised through the plates, at least two at each manifold area. The ports and the fins are formed so that the plates can be rotated 180° without the relative overall appearance being changed, i.e., the ports of the rotated plate will still be in mating position with the ports of an unrotated plate when the two plates are stacked. Bushings of compressible, fluid-impervious material are inserted into two diagonally opposite ports in each plate and a gasket is inserted in a groove in the upper surface of the peripheral wall around the plate so that fluid does not flow between the contacting surfaces of the gasket and bushing with the bottom surface of the plate immediately above.
Brief Description of the Figures
[0009]
Fig. 1 is a schematic diagram illustrating the structure of two adjacent interior plates according to the present invention.
Fig. 2 is a schematic diagram illustrating a frame which can be employed to form a peripheral wall around a plate.
Fig. 3 is a schematic diagram illustrating an embodiment of the plates of a plate stack heat exchanger in accordance with the present Invention.
Fig. 4 is a schematic diagram illustrating a unitary form of construction for the wall and bushing gaskets.
[0010] The same elements or parts throughout the figures of the drawing are designated by the same reference characters, while equivalent elements bear a prime designation.
Detailed Description of the Invention
[0011] Fig. 1 shows a schematic view of two interior, adjacent, finned-channel plates 10 and 12 for a heat exchanger 50 (Figure 3) in accordance with the present Invention. The lower and upper plates 10 and 12 are preferably rectangular and are formed with parallel, longitudinal, upstanding fins 16 which define longitudinal channels 18 between them. The plates may be formed of metal by an extrusion process and areas 20 and 21 (see Fig. 2) can be formed later where the fins 16 are milled off at each end. A pair of spaced fluid-entry ports 22 and 24 are drilled at one end toward the corners of the plates, and another pair of ports 26 and 28 are drilled similarly at the other end.
[0012] A frame 30 is placed upon and bonded to the periphery of the upper surface of each finned plate, thus forming a wall 31 around the plate and a well or manifold 32, 33 at each end where the fins 16 were milled off. Two diagonally opposite ports on each plate are fitted with a bushing insert 34 which extends upwards as far as the top of the wall 31 of the frame 30 and the tops of the fins 16, the top surfaces of these members forming a flat plane. The bushings 34 are preferably formed from a compressible material, such as a heat-resistant elastomer, in which case they may extend slightly above the aforementioned flat plane, or may be formed from a metal with a groove in the upper surface in which a circular gasket 36, or 0-ring, can be inserted. The frame 30 is also preferably formed with a groove in its upper surface in which a gasket 38 is inserted. The bottom surface of the interior plates 10 and 12, as well as that of the top plate 14, must be flat surfaces so that they make good contact with the gaskets 38 and 36 on the frames 30 and bushings 34 of the plates underneath the surfaces. The gaskets 36 and 38, of course, prevent the passage of fluids.
[0013] The bottom plate 10' (see Fig. 3) in the stack of plates is formed somewhat differently from the interior plates 10, 12, etc. The bottom plate 10' is formed with only two ports 24' and 28', each in a different manifold area and each on the same longitudinal side of the plate. One port 24' is the entry port for one fluid (B), e.g., cool air, and the other port 28' is the entry port for a second fluid (A), e.g., hot oil which is to be cooled. A bushing 34 is inserted through the entry port 24' for the fluid which is not to be circulated through the channels 18 in the bottom plate 10' thereby transforming this port into a non-dispersive port, i.e., a port through which the fluid flows only to the next plate 12 above the bottom plate 10'.
[0014] The arrows indicate the direction of the fluid flows. Thus, pressurized fluid A enters the bottom plate 10' through inlet port 28', fills the manifold 33 and a portion proceeds through the channels 18 between the fins 16 and up through the inlet port 22 in the second plate 12. A second portion proceeds directly through the non-dispersive port 28 in the second plate 12 through the inlet port 28 in the third plate 10 where it provides the source of fluid flow to the left as in the first plate.
[0015] Pressurized fluid B enters the bottom plate 10' through non-dispersive port 24' and is prevented from flowing in the bottom plate 10' by the bushing 34. Fluid B goes through the inlet port 24 in the second plate 12 and fills the manifold 32 on the left side. A portion of the manifold fluid flows to the right through the channels 18 and then up through non-dispersive port 26 in plate 10 and port 26 in plate 11. It leaves the plate stack through the outlet duct 42 1n the top plate 14 which is formed with two outlet ducts, 42 for fluid B and 40 for fluid A. Fluid B always flows to the right in alternate plates, e.g., plates 12 and 11. For fluid B, the ports 24' and 24 1n each plate are inlet ports and the ports 26 diagonally opposite are outlet ports. For fluid A, the ports 28' and 28 are inlet ports and the ports 22 are outlet ports. The flows in the channels 18 for fluid A and B are counterflows.
[0016] It should be noted that many more interior plates are present even though omitted 1n the drawing. All interior plates 10, 11, 12 have the same construction although any two adjacent plates are rotated by 180° from each other. (Plate 10 may differ only in the omission of a port 26.)
[0017] In Fig. 4, there is shown a unitary form of construction for a gasket 62 which may be inserted in a groove along the top of the peripheral wall and the circular gaskets 60 which may be put on the top of the bushings 34.
a plate having an upper surface and a flat lower surface, the upper surface having flat ends on opposite sides thereof, the upper surface bearing a peripheral wall upstanding therefrom, a plurality of upstanding, spaced fins being centrally located upon said upper surface and extending between said flat ends, the spaces between said fins defining a plurality of spaced channels, the ends of said fins and the upstanding peripheral wall defining a pair of manifolds, one at each end of said upper surface,
the plate being formed with a set of two spaced ports therethrough in each manifold area at such locations that the plate may be rotated 180° from another such plate and the ports in both plates will still occupy mating locations, the upper surfaces of the fins and the peripheral wall being coplanar; and
a pair of bushings which fit into and are located in two diagonally opposite ports, the bushings extending upward at least to the plane formed by the peripheral wall and fins.
said plate is rectangular.
said bushings are formed from a compressible, fluid-impervious material so that, when they are in contact with the flat bottom part of another plate, fluids cannot flow past the contacting surfaces.
said upstanding peripheral wall comprises a frame which is affixed to the upper surface of the plate at its periphery.
the plate is formed with a groove along the upper surface of the peripheral wall; and
the plate further includes a gasket which is fitted into the groove in the peripheral wall and extends upward at least to the plane formed by the peripheral wall and the fins.
said gasket and bushings are formed from a compressible, fluid-impervious material so that, when they are in contact with the flat bottom part of another plate, fluids cannot flow past the contacting surfaces.
a plurality of interior plates stacked one upon another, each plate having an upper surface and a flat lower surface, the upper surface having flat ends on opposite sides thereof, the upper surface bearing a peripheral wall upstanding therefrom, a plurality of upstanding, spaced fins being centrally located upon said upper surface and extending between said flat ends, the spaces between said fins defining a plurality of spaced channels, the ends of said fins and the upstanding peripheral wall defining a pair of manifolds, one at each end of said upper surface,
each plate being rotated 180° with respect to the next lower plate;
a pair of bushings which fit into and are located in two diagonally opposite ports, the bushings extending upward at least to the plane formed by the peripheral wall and fins;
a bottom plate similar to said interior plates except that it is formed with only three ports, two in one manifold area and one in the other manifold area, the two diagonally opposed ports having bushings inserted therein; and
a top plate having a flat lower surface and having two ports formed therein, one above each of two non-diagonally opposed ports located at opposite manifold areas of the interior plate immediately below the top plate.
all said plates are rectangular.
said bushings are formed from a compressible, fluid-impervious material so that, when they are in contact with the flat bottom surface of another plate, fluids cannot flow past the contacting surfaces.
the upstanding peripheral walls of each of the interior and bottom plates comprise a frame which is affixed to the upper surface of the plate at its periphery.