HEAT EXCHANGER CONNECTION PLATE APPARATUS

[0001] The present application claims priority from U.S. Provisional Patent Application Serial No. 60/868,220, filed December 1, 2006 and entitled "HEAT EXCHANGING CONNECTION PLATE APPARATUS" (Attorney Docket No. 11527/L) which is hereby incorporated herein by reference in its entirety for all purposes.

FIELD OF THE INVENTION

[0002] The present invention relates to electronic device manufacturing and more particularly to heat exchangers.

BACKGROUND OF THE INVENTION

[0003] Gaseous effluents from the manufacturing of electronic materials and devices may include a wide variety of chemical compounds which are used and/or produced during manufacturing. During processing (e.g. physical vapor deposition, diffusion, etch perfluorocompound (PFC) processes, epitaxy, etc.), some processes may produce undesirable byproducts including, for example, PFCs or byproducts that may decompose to form PFCs. PFCs are recognized to be strong contributors to global warming. These compounds may be harmful to human beings and/or the environment. The harmful compounds must be removed from the gaseous effluent before the gaseous effluent is vented into the atmosphere.

[0004] Harmful compounds may be removed from the effluents or converted into non-harmful compounds via a process known as abatement. During an abatement process, the harmful compounds used and/or produced by electronic device manufacturing processes may be destroyed or converted to

less harmful or non-harmful compounds (abated) which may be further treated or emitted to the atmosphere. [0005] , It is known that an effluent stream may be abated in a thermal abatement reactor which heats, and burns or oxidizes the effluent stream, thereby converting the harmful compounds into less harmful or non-harmful compounds, and then may quench and wet scrub the effluent stream. [0006] In many cases a recirculating water spray system may be used to quench and/or scrub the abated effluent. When the sprayed water contacts the thermally abated effluent, heat is typically transferred to the water. The heated water may be collected in a reservoir, and then pumped through filters to remove particulates and through a heat exchanger to reduce the temperature of the water so that it may be used again to quench/scrub additional thermally abated effluent.

[0007] Many conventional heat exchangers are difficult and/or expensive to connect to an abatement system, and in some cases, may be susceptible to corrosion due to such connections. Accordingly, a need exists for improved heat exchanger designs.

SUMMARY OF THE INVENTION

[0008] In some embodiments the invention provides a heat exchanger including: a first frame member; a second frame member; one or more heat transfer plates between the first frame member and the second frame member, wherein the one or more heat transfer plates are adapted to receive and distribute one or more fluids; and a connection sheet between the first frame member and the one or more heat transfer plates, wherein the connection sheet is adapted to couple to a pipe.

[0009] In other embodiments, a method of making a heat exchanger is provided, including: clamping one or more heat transfer plates between a first frame member and a second frame member, wherein the one or more heat transfer plates are adapted to receive and distribute one or more fluids; and providing a connection sheet between the first frame member and the one or more heat transfer plates, wherein the connection sheet is adapted to couple with a pipe. [0010] In still other embodiments, an electronic device manufacturing abatement system is provided, including: an electronic device process tool; an abatement reactor; a heat exchanger including a first frame member; a second frame member; one or more heat transfer plates between the first frame member and the second frame member, wherein the one or more heat transfer plates are adapted to receive and distribute one or more fluids; and a connection sheet between the first frame member and the one or more heat transfer plates, wherein the connection sheet is adapted to receive a pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Fig. 1 is a side schematic view of a prior art heat exchanger.

[0012] Fig. 2 is a side schematic view of a heat exchanger according to one embodiment of the invention. [0013] Fig. 3 is a top schematic view of a heat exchanger in accordance with the present invention.

[0014] Figs. 4A and 4B are top schematic views of heat exchange plates for a heat exchanger in accordance with some aspects of the invention.

[0015] FIG. 5 is a schematic view of an exemplary abatement system provided in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0016] It is known that one type of heat exchanger which may be used in such a "burn/wet" abatement system is a plate and frame heat exchanger 50 (See Fig. 1) . Plate and frame heat exchangers are typically formed from several generally planar heat transfer plates 52 which are sandwiched between first frame member 54 and second frame member 56. Through a system of conduits and gaskets (not shown) , two separate, non-fluid communicating, interleaved flow channels (not shown) may be created in the heat exchanger, providing a very large heat transfer surface area as compared to the footprint of the heat exchanger. In the abatement scenario described above, the heat exchanger may be used to cool the recirculated water, such as to transfer heat from the recirculated water to a house chilled water system, for example .

[0017] Conventional plate and frame heat exchangers may provide fluid inlet and outlet connections to the two separate channels formed between the heat conducting plates by employing flanged pipe connectors 58. In Fig. 1, only two pipe connectors 58 are shown in the side view. Two additional pipe connectors are hidden behind pipe connectors 58. The flanges 60 on each pipe connector 58 may extend between the first (top) frame member 54 and the surface of the adjacent (top) heat conducting plate 52, thus providing a means for securing the pipe connector to the heat exchanger. Although the first frame member 54 is depicted as having a flat bottom such that the frame member touches the flanges but not the heat transfer plates, it is understood that the bottom of the frame member may have recesses designed to encompass the flanges so that the frame member may apply force not only to the flanges, but to the

heat transfer plates as well. The pipe connector 58 creates a fluid pathway into or out of each channel in the heat exchanger. Each connector flange 60 may be compressed between the first frame member 54 and the adjacent heat conducting plate 52 and sealed with a gasket (not shown) placed between the connector flange 60 and the adjacent heat conducting plate 52. The threaded ends 62 of the pipe connectors 58 may protrude through holes 64 (shown in phantom) in the first frame member 54. The threaded end 62 of each connector 58 may then be mated to an adapter (not shown) that enables the attachment of pipes made from polyvinyl chloride (PVC), or another corrosion-resistant plastic to the first frame member 54.

[0018] Heat exchanger flanged pipe connectors 58 are typically made of an expensive corrosion-resistant alloy and add height to the total heat exchanger and its connections. Additionally, the connectors, being composed of a less reactive metal in the galvanic series, may promote the corrosion of the frame members that hold the fluid conducting plates together.

[0019] The present invention provides improved plate and frame heat exchangers. As described above, conventional plate and frame heat exchangers employ corrosion-resistant metal alloy inlet and outlet pipe connectors, which add expense and height to the heat exchanger, and increase the risk of corrosion for the heat exchanger components. The present invention eliminates conventional flanged metal pipe connectors and replaces them with one or more pipe connector sheets, made of PVC, or of another corrosion resistant material. The pipe connector sheets may be located between a frame member and the heat transfer plates. The connector sheets may have holes which line up on one side with fluid channels inside the heat exchanger, and on the other side

with holes in the frame member. The holes in the connector sheets may be threaded or not threaded, e.g., slip connector holes, or friction fittings, into which pipe may be connected. Thus, in some embodiments, externally threaded piping may be connected to the heat exchanger through the holes in the first frame member by screwing the piping into the threaded holes in the connector sheet. In other embodiments, non-threaded pipes may be fitted into non- threaded connector holes in the connector sheet. The non- threaded pipes may be retained by friction (e.g., a tight fit between the piping and the connector sheet hole) , or solvent-welded, glued or otherwise suitably secured in the connection holes .

[0020] In some embodiments, a short PVC or other corrosion resistant plastic pipe may be secured into the holes in the connector sheet to provide an attachment point outside of the heat exchanger for fluid supply and return pipes. Conventional pipe fitments may then be used to allow the connection of pipes to the attachment points without rotating either the attachment points or the supply and return pipes.

[0021] The present invention may reduce cost, eliminate the use of metal to PVC adapters, and reduce the potential for galvanic corrosion.

Heat Exchanger Structure

[0022] Fig. 2 is a side schematic view of a heat exchanger 100 according to some embodiments of the invention, Heat exchanger 100 may include first frame member 102 and second frame member 104. Sandwiched between first frame member 102 and second frame member 104 may be multiple heat transfer plates 106. Seven heat transfer plates are shown, but it is understood that fewer or more may be used. By

"sandwiched" it is meant that the heat transfer plates 106, which may be generally planar in shape, are stacked one on top of the other between first frame member 102 and second frame member 104, in substantially overlapping contact with each other and with the first and second frame members 102 and 104. It is understood that once the heat exchanger 100 is assembled, it may be placed in any spatial orientation, with first frame member 102, and plates 106 being, for example, above, below or on the same level as second frame member 104.

[0023] Also sandwiched between first frame member 102 and second frame member 104 (e.g., between first frame member 102 and heat transfer plates 106) may be one or more connection sheets 108. Connection sheet 108, viewed in plan, may have, but does not need to have, the same general outline and size as the heat transfer plates 106. This outline may be rectangular, oval or any other suitable shape. [0024] The sandwiched structure of first frame member 102, second frame member 104, heat transfer plates 106 and connection sheet (s) 108 may be held together by multiple bolts 110, or other suitable fasteners, which may extend through at least first frame member 102 and second frame member 104. Although shown as passing through first frame member 102 and second frame member 104 near the edges of the frame members, it is understood that the bolts 110 may be employed at any suitable location (e.g., through the center, in the corners, etc., of the frame members). Any other suitable apparatus, such as, for example, a vice, a clamp, etc. (not shown) may be used to hold together the components of the heat exchanger 100.

[0025] In some embodiments, bolts 110 may be used not only to hold the heat exchanger apparatus together, but also to apply compressive force to the frame members 102, 104,

heat transfer plates 106 and the connection sheet (s) 108. The purpose for placing compressive force on these components may be to seal the junctures between each adjacent components. Sealing may be achieved either with or without suitable gaskets (see, e.g., gaskets 304a and 304b in Figs. 4A and 4B) . Higher fluid pressures inside the heat exchanger may require greater compressive force to be applied by the bolts 110. In some of these embodiments, the assembler of a heat exchanger may tighten the bolts 110 until such time as the distance between first frame 102 and second frame 104 reaches a predetermined distance. This may indicate to the assembler that the bolts have been tightened an appropriate amount for the intended use of the heat exchanger .

[0026] First frame member 102 may include one or more frame openings 112, which are positioned to allow one or more pipes, e.g., fluid supply or return pipes, to pass through the frame member 102 and connect with the connection sheet (s) 108. Frame openings 112 may be round holes, for example, or any other suitably shaped holes, through first frame member 102 and may have a diameter which is selected to be the same, slightly larger or larger than the external diameter of the pipes. In some embodiments, first frame member 102 may have four frame openings 112, corresponding to two supply pipes and two return pipes (see, e.g., Fig. 3) More or fewer frame openings may be used. [0027] In a low pressure embodiment, e.g., where the fluids to be heat exchanged are flowed through the heat exchanger 100 at low pressures, the frame members 102 and 104 may have one or more large central openings designed to pass more than one or all of the supply and return pipes, instead of multiple openings designed to pass one pipe each. In some low pressure embodiments, the frame members 102 and

104 may contact the connector sheets (s) 108 and/or the heat transfer plates 106 only around the perimeter of the sheets/plates.

[0028] Connection sheet (s) 108 may include connection point apertures 114, which may be holes which are adapted to receive and secure supply and return pipes (not shown) . The connection point apertures 114 may be substantially aligned with the frame openings 112 such that pipes may be passed through frame openings 112 and secured (e.g., screwed, friction fitted and/or solvent welded) within connection point apertures 114. The connection point apertures 114 may also be substantially aligned with internal conduits (not shown) in the heat exchanger 100, so that fluids may be supplied to and returned from the heat exchanger 100, as discussed in more detail below. Connection point apertures 114 may be of substantially the same diameter as the external diameter of any supply and/or return pipes, or slightly larger, so as to allow the pipes to be fitted and/or secured therein. In some embodiments, connection sheet (s) 108 may have four connection point apertures, to receive and retain two supply and two return pipes. More connection point apertures 114 may be used.

[0029] First frame member 102 and second frame member 104 may be constructed of carbon steel, stainless steel, or any other suitable materials. Heat transfer plates 106 may be formed of stainless steel, titanium, nickel, tantalum, alloys thereof or any other appropriate material, such as, for example, polytetrafluoroethylene (e.g., Teflon®) or other plastic materials suitable for particularly corrosive materials .

[0030] Connection sheet (s) 108 may be formed of an insulating and/or corrosion resistant material such as, for example, polyvinyl chloride (PVC) or chlorinated polyvinyl

chloride (CPVC). Connection sheet (s) 108 may be machined and/or formed to house connection point apertures 114 and/or connection point apertures 114 may be machined and/or formed as an integral part of connection sheet (s) 108. Connection sheet (s) 108 may be of any appropriate thickness and/or shape to provide connection from external piping (not shown) into the heat exchanger 100. In some embodiments, connection sheet (s) 108 may total about 0.5 to about 2 inches or more in thickness or about 1 to about 1.5 inches in thickness.

[0031] Connection point apertures 114 are depicted in Fig. 2 as non-threaded holes. It is understood that they may be threaded by, for example, cutting threads directly into the sides of the holes.

[0032] Fig. 3 is a top schematic view of an exemplary embodiment of the heat exchanger 100 of Fig. 2. The heat exchanger 100 includes four frame openings 112a-d and four connection point apertures 114a-d, to form four frame opening/connection point aperture combinations. Two of the frame opening/connection point aperture combinations function as inlets through which fluid may be supplied to the heat exchanger 100 and two of the frame opening/connection point aperture combinations function as outlets through which fluid may be returned from the heat exchanger 100, as described in further detail below. Connection point apertures 114a-d are depicted in Fig. 3 as being smaller in diameter than frame openings 112a-d, but in other embodiments, connection point apertures 114a-d may be of any suitable diameter. Although four frame opening/connection point aperture combinations are shown in Fig. 3, in other embodiments, more than four may be employed. [0033] In this and other embodiments, eight bolts 110 pass through at least first frame member 102 and second

frame member 104 (not shown) to secure the heat transfer plates 106 (not shown) and connection sheet (s) 108 between the frame members. More or fewer bolts 110, e.g., 1, 2, 3, 4, 5, 6, 7, 9, 10 or more, may be used as appropriate. For example, in high fluid pressure embodiments, a greater number of bolts may be used than in low fluid pressure embodiments. In addition, as stated above, the bolts 110 may, in some embodiments, be placed in locations other than around the perimeter of first frame 102.

[0034] Figs. 4A and 4B are top schematic views of a first exemplary heat transfer plate 106a and a second exemplary heat transfer plate 106b, respectively, which may be used in heat exchanger 100 of Figs 2 and 3. Each heat transfer plate 106a-b may include cooling patterns 302. Cooling patterns 302 may be corrugated, stamped into, brazed on, or otherwise formed on or secured to the surface of heat transfer plates 106a-b and may be of any suitable shape (e.g., chevrons, bar-shaped, etc.) to facilitate turbulence and/or heat transfer.

[0035] The first heat transfer plate 106a (Fig. 4A) may have a gasket 304a formed thereon and/or attached thereto. Gasket 304a may serve to create a seal between stacked heat transfer plates 106a-b, and direct or confine fluid flow by defining channels through which fluid may flow, as will be discussed in more detail below. Similarly, the second heat transfer plate 106b (Fig. 4B) may have a gasket 304b formed thereon and/or attached thereto. Gasket 304b may also serve to create a seal between heat transfer plates 106a-b, and direct or confine fluid flow by defining channels through which fluids may flow, as described in more detail below. [0036] The first heat transfer plate 106a (Fig. 4A) may have conduit holes 306a-d formed therethrough, and the second heat transfer plate 106b (Fig. 4B) may also have

conduit holes 306e-h formed therethrough. Multiple heat transfer plates 106a-b may be stacked on top of one another, such that the first heat transfer plates 106a are interleaved within the second heat transfer plates 106b to form an "ababab..." pattern. For example, in at least one embodiment of the invention, about 22 heat transfer plates 106a-b may be alternatingly stacked to form part of the heat exchanger 100. Other numbers of heat transfer plates may be used. When multiple heat transfer plates 106a, b are stacked in an "ababab..." pattern, conduit holes 306a-d in plates 106a may align with holes 306e-h, respectively, in plates 106b. Stacked thus, alternating conduit holes 306a, e form a first conduit; alternating conduit holes 306b, f, form a second conduit; alternating conduit holes 306c, g from a third conduit; and alternating conduit holes 306d,h form a fourth conduit. The four conduits may align with connection point apertures 114a-d, respectively, (Fig. 3) of the heat exchanger 100 when connection sheet 108 is placed on the stack of heat transfer plates 106a, b.

[0037] The four conduits may combine with the gaskets 304a and 304b and heat transfer plates 106a, b to create two separate, high surface area, interleaved spaces, or channels, inside the heat exchanger 100. The creation and operation of the two separate interleaved spaces will be discussed in more detail below.

[0038] The gaskets 304a and 304b may be made of ethylene propylene diene monomer (EPDM) , Neoprene, Viton ^® or other suitable materials.

Operation of Connection Point Apertures

[0039] In operation, with reference to Figs. 2 and 3, pipes (not shown) (e.g., PVC or CPVC pipes which conduct fluid media to and from heat exchanger 100) may be passed through frame openings 112 and secured within connection

point apertures 114 of connection sheet (s) 108. It is understood that any arrangement which allows fitting of and/or securing pipes to the connection sheet 108 may be used. In one embodiment, a pipe may be friction fitted into a connection point aperture 114. In another embodiment, a pipe may be solvent welded and/or glued into a connection point aperture 114. In another embodiment, a gasket sealed connection may be used in which an O-ring may be seated in a groove in a wall of connection point aperture 114 and aligned with a groove on the exterior wall of a pipe to be secured in the connection aperture 114. In still another embodiment, an externally threaded pipe may be screwed into a threaded connection point aperture 114b. Any other appropriate connections may be used.

[0040] As discussed above, heat exchanger 100 may be designed to transfer heat from a first medium flowing through a first channel to a second medium flowing through a second channel, thus cooling the first medium and heating the second medium. In some embodiments, the first medium may be supplied to the heat exchanger 100 through a first pipe which is connected to connection point aperture 114a

(FIG. 3) . Connection point aperture 114a may be in fluid communication with the first channel (not shown) through the heat exchanger. The first medium therefore may flow from the supply pipe into the first channel. The second medium may be supplied to the heat exchanger 100 through a second pipe which may be connected to connection point aperture 114b (FIG. 3), which may be in fluid communication with the second channel (not shown) through the heat exchanger 100. As the two media flow through the channels in the heat exchanger 100, heat may be transferred from the first medium to the second medium, thereby increasing the temperature of the second medium and reducing the temperature of the first

medium. The first medium may exit the heat exchanger 100 through connection point aperture 114c (FIG. 3) , which may be in fluid communication with the first channel, and the second medium may exit the heat exchanger 100 through connection point aperture 114d (FIG. 3) which may be in fluid communication with the second channel. Return pipes may be connected to connection point apertures 114c and 114d and the first and second fluids may be flowed away from the heat exchanger therethrough. Connection sheet (s) 108 and particularly connection point apertures 114-d may be arranged (e.g., angled, aligned, etc.) so as to facilitate connection of external fluid sources (e.g., pipes) to the heat exchanger 100 and to conduct the fluids to and/or away from the heat transfer plates 106. Although connection point apertures 114a and 114b were described in this example as the inlets and connection point apertures 114c and 114d were described as the outlets, it is understood that any arrangement may be used.

Operation of the Heat Transfer Plates , Conduits and Gaskets [0041] In some embodiments, a first fluid supply pipe (not shown) may be coupled to the first conduit (formed by holes 306a, e) through connection point aperture 114a. Any fluid which flows through the first conduit will be able, by virtue of the channels created by gaskets 304a, to flow across all heat transfer plates 106a. On the other hand, any fluid which flows through the first conduit will be prevented, by virtue of the channels created by gaskets 304b, from flowing across any heat transfer plate 106b. Conversely, any fluid which flows through a second supply pipe (not shown) coupled to the second conduit (formed by holes 306b, f) through connection point aperture 114b, will be prevented, by virtue of the channels created by gaskets

304a, from flowing across any heat transfer plate 106a, but will be able, by virtue of the channels created by gaskets 304b, to flow across all heat transfer .plates 106b. In this way, first and second fluids may be flowed into the heat exchanger 100 and across alternating heat transfer plates 106a, b without mixing together. Similarly to the way in which gaskets 304a, b work with the first conduit and the way in which gaskets 304a, b work together with the second conduit, gaskets 304a,b work with the third and fourth conduits to return the first and second fluids from the heat exchanger 100 and out connection point apertures 114c and 114d, without allowing the fluids to mix.

[0042] As the fluids, directed by the four conduits and gaskets 304a, b, flow across alternating heat transfer plates 106a, b, heat may flow from a first hotter fluid across each heat transfer plate 106a, b to a second cooler fluid. A high rate of thermal transfer between the hotter fluid and the cooler fluid may be achieved.

[0043] Other conduit, gasket and heat transfer plate configurations may be employed. For example, some heat exchangers may have more than two fluid channels therein. In such cases, if there is a third or fourth channel, each additional channel may have at least one additional inlet and conduit, and at least one additional outlet and conduit. The gaskets and heat transfer plates may be designed and stacked so as to direct the fluids from different conduits to flow across specific plates and not allow them to mix. Thus in a three channel heat exchanger, heat exchange plates may be stacked in configurations such as "abacabaca", "abcabcabc" or any other suitable pattern.

[0044] In other embodiments, each channel may have more than one inlet and/or more than one outlet.

[0045] The foregoing description discloses only exemplary embodiments of the invention. Modifications of the above disclosed apparatus and methods which fall within the scope of the invention will be readily apparent to those of ordinary skill in the art. For instance, a connection sheet may be used in other types of heat exchangers, such as shell and tube heat exchangers wherein secure and reliable connection of external piping to the heat exchanger is desired. Further, the connection sheet may be formed as part of the frame (e.g., the first frame member) or as another part of the heat exchanger.

[0046] The exemplary embodiments discussed herein have both inlets and outlets located on one end, i.e., entering and exiting through one frame member (such as a top or first side frame member) . It is understood that a heat exchanger may have inlets and outlets located on both ends. In some embodiments, both fluid streams may enter the heat exchanger on a first end, and exit the heat exchanger on a second end. In this embodiment, the heat exchanger may have one or more connector sheets between the heat transfer plates and both frame members. In addition, one fluid stream may enter on the first end and exit on the second end, while the other fluid stream may enter on the second end and exit on the first end. In some embodiments, the connector sheet (s) may- have channels rather than straight ports, so that flow can actually be routed within the connector plate (s). [0047] FIG. 5 is a schematic view of an exemplary abatement system 500 provided in accordance with the present invention. With reference to FIG. 5, the abatement system 500 includes an abatement reactor 502 coupled to the heat exchanger 100 by a supply pipe 504a and return pipe 504b. Heated scrubbing or other fluid from the abatement reactor 502 flows via supply pipe 504a to the heat exchanger 100

where it is cooled and recirculated back to the abatement reactor 502 via supply pipe 504b for reuse by the abatement reactor 502.

[0048] Accordingly, while the present invention has been disclosed in connection with exemplary embodiments thereof, it should be understood that other embodiments may fall within the spirit and scope of the invention, as defined by the following claims.