Patent Grant
9417011
The invention relates to a heat exchanger with fittings which self-align when inserted into a rigid manifold.
Most conventional heat exchangers use fluid connecting fittings that interface with the vehicle transmission, engine, power steering etc. via tube or hose type fluid conduits. These conduits are relatively flexible, and can accommodate a certain degree of misalignment or variation in the heat exchanger fittings.
Recently, there is a trend to provide fluid connections that require the heat exchanger to interface directly with a rigid manifold. Such rigid manifolds use machining to create fitting receptacles or “sockets” to receive the heat exchanger fittings. But today's machining technology can achieve dimensional tolerances with much greater precision than brazed heat exchanger product assemblies, as the latter involve significant stack up tolerance variation. This can create a conflict in dimensional control needed to achieve a manufacturable heat exchanger assembly, and a reliable seal.
There is a need to provide a more manufacturable heat exchanger with fittings which self-align during insertion into a rigid manifold.
According to an embodiment, there is provided a heat exchanger, comprising: an inlet opening provided with an inlet fitting; an outlet opening provided with an outlet fitting, wherein the inlet and outlet fittings are hollow and have open ends, and wherein the fittings face in the same direction and are spaced apart from one another; wherein each of the fittings have a cylindrical base portion and a cylindrical top portion, wherein each of the fittings is provided with a circumferential groove extending about its entire circumference, and a resilient sealing element is received in the groove; wherein the base portion of each of the fittings has a flat, annular sealing surface which is sealed to a surface of the heat exchanger in an area surrounding the inlet opening or the outlet opening.
According to an embodiment, the base portion of each of the fittings has a radially outwardly extending planar base flange, and the flat, annular sealing surface comprises a bottom surface of the planar base flange, wherein said surface of the heat exchanger is flat.
According to an embodiment, said surface of the heat exchanger comprises an outer surface of a plate comprised of an aluminum brazing sheet, wherein the inlet and outlet fittings are formed of aluminum or an aluminum alloy, and wherein the inlet and outlet fittings are both sealed to the outer surface of said plate by brazing.
According to an embodiment, the cylindrical base portion has a larger diameter than the cylindrical top portion, and the circumferential groove and the resilient sealing element may be provided in the top portion or in the base portion.
According to an embodiment, the circumferential groove and the resilient sealing element are provided in the base portion, and each of the fittings further comprises a sloped surface which forms a transition between the base portion and the top portion of the fitting, such that the base portion extends to a bottom edge of the sloped surface. The circumferential groove of the base portion of each said fitting may be located approximately midway between the ends, and each of the fittings may have a top end with a radially inwardly extending sloped surface.
According to an embodiment, the top portion has a larger diameter than the cylindrical base portion, and wherein the circumferential groove and the resilient sealing element are provided in the top portion.
According to an embodiment, each of the fittings has a top end with a radially inwardly extending sloped surface located between the resilient member and the top end, and wherein the top end of the fitting has a smaller diameter than an outside diameter of resilient member.
According to an embodiment, the groove has a rectangular cross-section and the sealing member comprises a sealing gland having a rectangular profile on its inner radial face, and having a spherical profile on its outer radial face.
According to an embodiment, the top portion of the fitting has a truncated spherical cross-section having a radius which is less than a radius of the spherical profile on the outer radial face of the sealing gland.
According to an embodiment, there is provided, in combination, a heat exchanger and a rigid manifold, wherein the heat exchanger has an inlet opening provided with an inlet fitting and an outlet opening provided with an outlet fitting, wherein the inlet and outlet fittings face in the same direction and are spaced apart from one another; wherein the rigid manifold comprises an inlet socket in which the inlet fitting is received, and an outlet socket in which the outlet fitting is received, the inlet and outlet sockets being spaced apart from one another; each of the fittings having a cylindrical base portion proximate to the inlet or outlet opening with which it is associated, and a cylindrical top portion distal therefrom, the base portion having a larger diameter than the top portion, wherein the base portion is provided with a circumferential groove extending about its entire circumference, and a resilient sealing element is received in the groove; each of the sockets having a cylindrical base portion proximate to an open mouth of the socket, and a cylindrical top portion distal therefrom, wherein the top portion of the socket receives the top portion of one of the fittings, and the base portion of the socket receives the base portion of the same fitting, and wherein an inner cylindrical surface of the base portion of the socket provides a sealing surface against which the resilient sealing member is received with a fluid-tight seal.
According to an embodiment, the sealing surface of each of the sockets has an inner diameter which is equal to or greater than a maximum outside diameter of the top portion of the fitting with which it is associated, plus a maximum diametrical position tolerance of a top end of the fitting.
According to an embodiment, each of the fittings further comprises a sloped surface which forms a transition between the base portion and the top portion of the fitting; wherein each of the sockets further comprises a sloped surface which forms a transition between the base portion and the top portion of the socket; and wherein the sloped surface of each fitting engages the sloped surface of the socket with which it is associated with the fitting completely inserted in the socket.
According to an embodiment, each of the fittings has a top end distal from the base, and wherein a distance from the top end of the fitting to the resilient member is greater than a distance from the open mouth of the socket to the bottom end of the top portion of the socket.
According to an embodiment, each of the fittings has a top end with a radially inwardly extending sloped surface, and wherein a distance between a bottom end of the sloped surface and the resilient member is greater than a distance from the open mouth of the socket to the bottom end of the top portion of the socket.
According to an embodiment, there is provided, in combination, a heat exchanger and a rigid manifold, wherein the heat exchanger has an inlet opening provided with an inlet fitting and an outlet opening provided with an outlet fitting, wherein the inlet and outlet fittings face in the same direction and are spaced apart from one another; wherein the rigid manifold comprises an inlet socket in which the inlet fitting is received, and an outlet socket in which the outlet fitting is received; each of the fittings having a cylindrical base portion proximate to the inlet or outlet opening with which it is associated, and a cylindrical top portion distal therefrom, the top portion having a larger diameter than the base portion, wherein the top portion is provided with a circumferential groove extending about its entire circumference, and a resilient sealing element is received in the groove; each of the sockets having an outwardly sloped base portion proximate to an open mouth of the socket, and a cylindrical top portion distal therefrom, wherein the top portion of the socket receives the top portion of one of the fittings, and the base portion of the socket receives the base portion of the same fitting, and wherein an inner cylindrical surface of the base portion of the socket provides a sealing surface against which the resilient sealing member is received with a fluid-tight seal; and wherein each of the fittings has a top end with a radially inwardly extending sloped surface located between the resilient member and the top end, and wherein the top end of the fitting has a smaller diameter than an outside diameter of resilient member.
According to an embodiment, the groove has a rectangular cross-section and the sealing member comprises a sealing gland having a rectangular profile on its inner radial face, and having a spherical profile on its outer radial face.
According to an embodiment, the top portion of the fitting has a truncated spherical cross-section having a radius which is less than a radius of the spherical profile on the outer radial face of the sealing gland.
The invention will now be described, by way of example only, with reference to the accompanying drawings in which:
a, 6 and 7 are cross-sectional side views showing the insertion of a fitting of the heat exchanger of
A heat exchanger 10 according to a first embodiment of the invention is described below with reference to
Heat exchanger 10 is shown alongside a rigid manifold 12. The heat exchanger 10 has a pair of fittings, namely an inlet fitting 14 and an outlet fitting 16, which are to be inserted into sockets 18 and 20 of manifold 12.
Heat exchanger 10 is shown as comprising a pair of heat exchanger plates, namely a top plate 22 and a bottom plate 24. The plates 22, 24 are sealed together at their peripheral edges, for example by brazing, and enclose a fluid flow passage 26 for flow of a fluid such as a liquid engine coolant from the inlet fitting 14 to the outlet fitting 16, in the direction of the arrows shown in
Although the structure of heat exchanger 10 is shown as comprising a single pair of plates 22, 24, it will be appreciated that the structure of heat exchanger 10, aside from the structure and location of fittings 14, 16, is relatively unimportant to the present invention, and is therefore variable. For example, heat exchanger 10 may comprise a stack of tubes or plates which are either self-enclosed or enclosed within a housing, and which do not necessarily have the appearance of plates 22, 24 of
A pair of openings 28, 30 is formed in the top plate 22 of heat exchanger 10. Opening 28 is an inlet opening which receives the inlet fitting 14 and opening 30 is an outlet opening which receives the outlet fitting 16. The fittings 14, 16 are sealingly connected to top plate 22, for example by brazing. In this embodiment, the openings 28, 30 are circular, although it will be appreciated that the shape of the openings depends on the shape of the fittings.
The fittings 14 and 16 are shown as being identical. Therefore, only the inlet fitting 14 will be described in detail below and the elements of fittings 14, 16 are identified with the same reference numerals. Except where otherwise indicated, the following description of inlet fitting 14 also applies to outlet fitting 16.
Fitting 14 has a base portion 32 through which fitting 14 is attached to the top plate 22, and a top portion 34 at the other end of fitting 14. The base portion 32 has a larger diameter than the top portion 34. An alignment axis A extends through fitting 14 and socket 18 and defines an axial direction. The central longitudinal axis C of the fitting 14 is also shown in the drawings. The alignment axis A and the central longitudinal axis C of the fitting 14 and socket 18 are co-linear when the fitting 14 and socket are in perfect alignment with one another, as shown in
The fitting 14 has a sidewall 36 which extends axially throughout the height of fitting 14, and which defines a hollow interior 38 of fitting 14. The sidewall 36 and interior 38 are shown as being generally cylindrical, and the ends of fitting 14 are open to permit fluid flow through hollow interior 38, into or out of the heat exchanger flow passage 26.
The base portion 32 of fitting 14 has a flat, annular sealing surface 41 which sits on top of top plate 22 and which is sealed to the outer surface of top plate 22 in an area surrounding the inlet opening 28, for example by brazing. In the embodiment shown in the drawings, the base portion 32 of fitting 14 has a planar base flange 40 extending radially outwardly from the base portion 32, with the annular sealing surface 41 comprising the bottom surface of the flange 40. However, it will be appreciated that the outwardly extending flange 40 may not be necessary in all embodiments, depending at least partly on the outer diameter of the base portion 32. The base flange 40 may also help to maintain the vertical orientation of fitting 14 during brazing, i.e. such that the center line of the fitting remains substantially parallel to axis A.
Located radially inwardly of sealing surface 41 is an annular ridge 42, separated from the sealing surface 41 by an axially extending shoulder 44. The shoulder 44 is provided at the inner peripheral edge of the annular sealing surface 41 and has an outer diameter which is slightly less than the diameter of the opening 28, and therefore sits inside the opening 28 with the shoulder 44 facing an edge of the opening 28, and may be sealed to the edge of opening 28 by brazing.
The base portion 32 of fitting 14 extends from the base flange 40 to a point 54 on the outer surface 46 of sidewall 36 which is the bottom edge of a sloped surface 56 (also referred to herein as “side chamfer 56”) of fitting 14. The side chamfer 56 forms a transition between the larger diameter base portion 32 and the smaller diameter top portion 34 of fitting 14.
Within the base portion 32, the outer surface 46 of sidewall 36 is provided with a groove 48. In the illustrated embodiment, the groove 48 is located approximately midway between the top and bottom ends of fitting 14, and is closer to point 54 than to the base flange 40. The groove 48 extends around the entire circumference of sidewall 36 and extends radially inwardly from the outer surface 46. The groove 48 has a height (measured axially) and a depth (measured radially) sufficient to accommodate a resilient sealing member such as O-ring 50. With the exception of the base flange 40 and groove 48, the base portion 32 has a substantially constant diameter.
The top portion 34 extends from the top end of fitting 14 to a point 58 on the outer surface 46 of sidewall 36 which is the top edge of side chamfer 56. The top portion 34 has a substantially constant diameter with the exception of an inwardly extending top chamfer 60 at the nose to ease insertion of the fitting 14 into socket 18.
The sockets 18, 20 of the rigid manifold 12 may be formed by machining. For convenience, socket 18 is referred to herein as the inlet socket because it receives the inlet fitting 14 and socket 20 is referred to as the outlet socket because it receives the outlet fitting 16. The sockets 18, 20 are in flow communication with a circulation system for a fluid, such as a liquid coolant, through respective manifold flow passages 62, 64.
The sockets 18 and 20 are shown as being identical. Therefore, only the inlet socket 18 will be described in detail below and the elements of sockets 18, are identified with the same reference numerals. Except where otherwise indicated, the following description of inlet socket 14 also applies to outlet socket 20.
The socket 18 has a base portion 66 defining an open mouth of socket 18. The base portion 66 has a cylindrical sealing surface 67 with a substantially constant diameter which is greater than the diameter of the base portion 32 of fitting 14, such that a fluid-tight seal is formed with the base portion 32 of fitting 14. A bottom chamfer 74 is provided at the bottom of base portion 66, extending from the bottom edge of sealing surface 67 of base portion 66 to the open mouth of socket 18, and providing the mouth with a diameter slightly greater than that of the remainder of the base portion 66.
The socket 18 also has a top portion 68 with a diameter smaller than the diameter of the base portion 66, through which the socket 18 is connected to the manifold flow passage 62. The top of socket 18 may be provided with a top chamfer 70 which forms a transition between socket 18 and manifold flow passage 62. With the exception of top chamfer 70, the diameter of the top portion 68 is substantially constant and is greater than the diameter of the top portion 34 of fitting 14, to enable the top portion 34 of fitting 14 to be received inside the top portion 68 of socket 18.
A side chamfer 72 forms a transition between the larger diameter base portion 66 and the smaller diameter top portion 68 of socket 18.
As mentioned above, the brazed construction of heat exchanger 10 involves significant stack-up tolerance variation. The stack-up tolerance variation is the sum of a number of individual variations in the manufacture, assembly and brazing of the heat exchanger components. For example, there are small variations in the size of openings 28, 30; the locations of openings 28, 30 on top plate 22 and relative to each other; the size and concentricity of the braze assembly shoulder 44; and the deviation of the fitting's central axis from vertical. In addition to the stack-up tolerances in the heat exchanger 10, there are relative tolerances due to thermal expansion and manifold hole machining. As a result, the location of the base of each fitting 14, 16 may deviate by more than about 0.5 mm from the nominal centreline defined along axis A, and the top end of each fitting 14, 16 may be angled by as much as 1.5-2 degrees from vertical (i.e. relative to axis A), meaning that the position of the top end of fitting may deviate by up to about 1 mm from vertical (axis A).
During insertion of fitting 14 into socket 18 the fitting 14 should become substantially centered in socket 18 so that the O-ring 50 seals with surface 67 within compression ranges recommended by the O-ring manufacturer. At the same time, contact between the O-ring 50 and any surfaces surrounding the bottom edge or open mouth of socket 18 should be avoided. These surfaces include the bottom chamfer 74 of socket 18, and the top and bottom edges of bottom chamfer 74. Contact with the bottom edge of socket 18 could damage the O-ring 50 and/or cause it to be ejected from the groove 48, which can compromise the seal. In addition, there should be no sliding metal-to-metal contact between the fitting 14 with the sealing surface 67 of socket 18. This sealing surface 67 may be smoothly machined and could be damaged by contact with the metal portions of fitting 14, which may also compromise the fitting to socket seal.
As further discussed below, the fittings 14, 16 and sockets 18, 20 are formed to permit insertion, centering and reliable sealing of the fittings 14, 16 within sockets 18, 20, while avoiding damage to the O-ring 50 and sealing surface 67. Reference is now made to
To prevent metal-to-metal contact between the top portion 34 of fitting 14 and the sealing surface 67 of socket 18, the inner diameter of base portion 66 is large enough such that there will be some clearance between the top portion 34 of fitting 14 and the sealing surface 67. Therefore, the inner diameter of base portion 66, and the inner diameter of sealing surface 67, may be equal to or greater than the maximum outside diameter of the top portion 34 of fitting 14, plus the maximum diametrical position tolerance of the top end of fitting 14. This will ensure that the top portion 34 will enter the socket 18 without contacting the bottom chamfer 74 or, as shown in
As shown in
The centering of fitting 14 continues as it is inserted, until the top chamfer 60 of fitting 14 slides upwardly past side chamfer 72 of socket 18 and the top portion 34 of fitting 14 begins to enter the top portion 68 of socket 18, as shown in
In order to prevent damage to the O-ring 50 as discussed above, it can be seen from
As insertion of fitting 14 continues, the groove 48 and O-ring 50 enter the base portion 66 of socket 18, with the O-ring 50 undergoing even compression and sliding upwardly along sealing surface 67, without any metal-to-metal contact between the fitting 18 and the sealing surface 67 of socket 18. Insertion continues until the side chamfer 56 of fitting 14 contacts the side chamfer 72 of socket 18 and the groove 48 and O-ring 50 are completely received inside the base portion 66 of socket 18, at which point insertion is complete. The fully inserted configuration is shown in
The angles of chamfers 56, 60, 70, 72 and 74 described above are in the range of about 30-60 degrees from the vertical (axial) direction, and it will be appreciated that the angles of side chamfer 56 and top chamfer 60 of fitting 14 are about the same as the angles of side chamfer 72 and top chamfer 70 of socket 18, respectively.
A second embodiment of the invention is now described below with reference to
The second embodiment of the invention provides a fitting 200 which may be an inlet or outlet fitting and which may form part of a heat exchanger including two such fittings 200 spaced apart from one another, and which may be otherwise similar or identical to heat exchanger 10 described above. The second embodiment also provides a socket 202 which may be an inlet or outlet socket and which may form part of a rigid manifold including two such sockets 202 spaced apart from one another, and which may be otherwise similar or identical to manifold 12 described above. As in the embodiment described above, the misalignment between fitting 200 and socket 202 is exaggerated, for clarity and ease of illustration.
The fitting 200 and socket 202 of the second embodiment are similar in structure to the fittings 14, 16 and the sockets 18, 20 of the first embodiment described above. Therefore, like elements of fitting 200 and socket 202 are identified in the drawings using like reference numerals and, unless otherwise noted below, the descriptions of the elements of fittings 14, 16 and sockets 18, 20 apply equally to fitting 200 and socket 202.
Fitting 200 has a base portion 32 at one end and a top portion 34 at its opposite end. The base portion 32 has a larger diameter than the top portion 34. Fitting 200 also has a sidewall 36 which defines a hollow interior 38. The sidewall 36 and interior 38 are generally cylindrical, and the ends of fitting 200 are open. The base portion 32 has a planar base flange 40 at its bottom end, the base flange 40 having a flat, annular bottom sealing surface 41 which sits on top of top plate 22, as well as an annular ridge 42 and an axially extending shoulder 44.
The outer surface 46 of sidewall 36 of fitting 200 has a side chamfer 56 which forms a transition between the larger diameter base portion 32 and the smaller diameter top portion 34 of fitting 200.
The main difference between fitting 200 and fittings 14, 16 is that the sealing element of fitting 200 is provided in the top portion 34 of fitting 200, proximate to the top end of the fitting 200. Therefore, the outer surface 46 of sidewall 36 is provided with a circumferential groove 48 located in top portion 34, the groove 48 accommodating a resilient sealing member such as O-ring 50.
Socket 202 has a base portion 66 defining an open mouth, with a bottom chamfer 74 at the bottom of base portion 66. Socket 202 also has a top portion 68 with a smaller diameter than the base portion 66, through which the socket 202 is connected to manifold flow passage 62. A side chamfer 72 forms a transition between the larger diameter base portion 66 and the smaller diameter top portion 68 of socket 202. Socket 202 is substantially identical in appearance and structure to the sockets 18, 20 described above. However, due to the location of the resilient sealing member on the top portion 34 of fitting 200, the cylindrical sealing surface 67 of socket 202 is necessarily located in the top portion 68 of socket 202. The sealing surface 67 has a substantially constant diameter which is greater than the diameter of the top portion 34 of fitting 200, such that a fluid-tight seal is formed with the resilient sealing element located in the top portion 34 of fitting 200.
As in the first embodiment, the inner diameter of base portion 66 of socket 202, may be equal to or greater than the maximum outside diameter of the top portion 34 of fitting 200, plus the maximum diametrical position tolerance of the top end of fitting 200. Thus, the inner diameter of base portion 66 is large enough such that the top portion 34 of the fitting 200 will enter the base portion 66 of socket 202 such that the O-ring will not be damaged by contact with the surfaces and edges surrounding the mouth of socket 202. Depending on the degree of misalignment, the top portion 34 of fitting 200 may directly enter the top portion 68 of socket 202 or may be guided into the top portion 68 by sliding contact of the top chamfer 60 upwardly along the side chamfer 72 of socket 202, as shown in
As can be seen from
A third embodiment of the invention is now described below with reference to
The third embodiment of the invention provides a fitting 100 which may be an inlet or outlet fitting and which may form part of a heat exchanger including two such fittings 100 spaced apart from one another, and which may be otherwise similar or identical to heat exchanger 10 described above. The drawings show only those portions of fitting 100 which are necessary for description of the third embodiment. Although not shown, it will be appreciated that the base of fitting 100 may be provided with a base flange, bottom sealing surface, ridge and shoulder similar or identical to base flange 40, bottom sealing surface 41, ridge 42 and shoulder 44 of fittings 14, 16 described above.
The third embodiment also provides a socket 102 which may be an inlet or outlet socket and which may form part of a rigid manifold including two such sockets 102 spaced apart from one another, and which may be otherwise similar or identical to manifold 12 described above. It will be appreciated that the drawings show only those portions of socket 102 which are necessary for description of the third embodiment, and the hollow interior of socket 102 will be in fluid flow communication with a manifold flow passage (not shown).
The fitting 100 has a base portion 104 through which fitting 100 is attached to the top plate of the heat exchanger, and a head 106 at the other end of fitting 100. The base portion 104 has a smaller diameter than the head 106. The fitting 100 has a sidewall 108 which defines a hollow interior 110 of fitting 100. The sidewall 108 and interior 110 are shown as being generally cylindrical and the ends of fitting 100 are open to permit fluid flow through the hollow interior 110.
The base portion 104 of fitting 100 is shown as being of substantially constant diameter. The head 106 of fitting 100 is shown as having the form of a truncated section of a sphere, being reduced in diameter at its lower edge 112 and at its upper edge 114. The lower edge 112 forms a transition point between the head 106 and base portion 104. The head 106 is of maximum diameter about midway between the lower edge and upper edge 112, 114. At this point the head 106 is provided with a circumferential groove 116 which houses a resilient sealing element in the form of an O-ring 118. The groove 116 divides the head 106 into an upper portion 107 extending from the top of groove 116 to the upper edge 114 of head 106, and a lower portion 109 extending from the bottom of groove 116 to the lower edge 112 of head 106.
The O-ring 118 is shown in
The socket 102 has an upper portion 120 of substantially constant diameter, the upper portion 120 having an inner cylindrical sealing surface 124 which is greater than the maximum diameter of the head 106 of fitting 100, such that a fluid-tight seal is formed with the head 106 of fitting 100. The socket 102 also has a lower portion 122 which is curved or chamfered radially outwardly from the bottom edge 126 of upper portion 120 toward the open mouth 128 of socket 102.
As part of a heat exchanger assembly, the fitting 100 may be radially and/or axially misaligned in substantially the same manner as fittings 14, 16 described above.
In
The gland 130 has an outer sealing surface 132 which is rounded when viewed in cross-section in an axial plane as shown in
In the fitting 100 shown in
It can be seen that the gland 130 has a height (the axial distance between the top and bottom of groove 116 or inner portion 134) which may be greater than that of O-ring 118. This provides the head 106 with a greater sealing surface 132 to ensure robust contact with the sealing surface 124 of socket 102, and allows a seal to be maintained in the event that there is significant tilting of the fitting 100 relative to the vertical (axial) direction. For example, the height of gland 130 may be greater than 50% of the height of the head 106, measured axially between the lower edge 112 and upper edge 114 of head 106.
It will be appreciated that the head 106 of fitting 100 may be modified without departing from the invention, particularly where the resilient sealing element comprises gland 130. For example, as shown in
Similarly, the upper portion 107 of head 106 does not necessarily have a continuously rounded profile as shown in
Although the invention has been described in connection with certain embodiments, it is not restricted thereto. Rather, the invention includes all embodiments which may fall within the scope of the following claims.
This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/763,747 filed Feb. 12, 2013, the contents of which are incorporated herein by reference.
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