BACKGROUND OF THE INVENTION
The present invention relates to plate-type heat exchangers, and, more particular, to heat exchangers comprising a stack of dished plates.
Plate-type heat exchangers comprising a stack of heat exchanger plates are well known for a variety of purposes, including heat exchange between oil and a heat exchange fluid. One category of this type of heat exchanger uses plates which have a generally planar plate bottom and a sloped peripheral sidewall extending around the bottom and these plates can be referred to as dished or tub shaped plates. The plates nest with adjacent plates in the stack. During assembly, the sidewalls are sealingly connected together, for example, by brazing, to form sealed flow passages for heat exchange fluids.
A known way of mounting a stacked plate heat exchanger is to mount a planar base plate at one end of the stack, for example, the bottom end. The base plate can be brazed to the heat exchanger i.e. with or without the use of a shim plate. In such designs where the base plate is brazed to the heat exchanger core, the first channel peripheral sidewall is the weakest location on the heat exchanger, as this sidewall is not covered by another core plate sidewall outside of it. A known solution to reinforce the first channel sidewall is to connect this bottom core plate to the base plate by means of a belt connector extending about the periphery of the core plate. The connecting belt can strengthen the weakest location of the heat exchanger but it increases the amount of material required and belts of this type can be difficult to manufacture and relatively costly. Generally, the stamping angle to form these belts is higher than 90 degrees, requiring the belts to be stamped in two directions. Because such belts are made from plates, the use of such belts results in high material usage, with the center of each plate being removed and not used. Another known solution to strengthen the first channel is to use a second core plate between the base plate and the first core plate.
There is a need for an improved heat exchanger of the aforementioned type with an improved attachment arrangement.
SUMMARY OF THE PRESENT DISCLOSURE
According to one embodiment of the invention, a heat exchanger comprises a heat exchanging core including a plurality of dish-type plates arranged in a stack with fluid flow passages being provided between adjacent plates in the stack. Each plate comprises a central main plate section having a peripheral edge, an edge wall extending outwardly from and around the peripheral edge at an acute angle to a plane defined by the main plate section, and inlet and outlet holes provided through the main plate section for passage of heat exchange fluids. The plates are in nested, sealed arrangement with one another and the main plate sections of adjacent plates are spaced from one another to form the fluid flow passages. A base plate for supporting the heat exchanging core is rigidly attached to one of the dish-type plates at one end of the stack. This base plate is formed with an integral ridge extending snugly along and adjacent to the edge wall of the one dish-type plate. At least one section of the ridge is spaced from an adjacent edge of the base plate so a to provide at least one mounting flange for the heat exchanger.
In an exemplary version of this heat exchanger, the integral ridge has a U-shaped transverse cross-section and has inner and outer ridge walls. The inner ridge wall extends parallel to an adjacent outer surface of the edge wall and is attached directly thereto.
According to another embodiment of the invention, a heat exchanger for heat exchange between two heat exchange liquids comprises a heat exchanging core formed of a plurality of formed plates arranged and connected to one another in a stack. The plates include first end plate (also called top core plate) and second end plate (also called the bottom core plate) and at least one intermediate plate arranged between the end plates. Each of the formed plates has a central main plate section and the first end plate and the at least one intermediate plate each have an edge wall extending outwardly from and around its respective main plate section at an acute angle to a plane defined by the main plate section. The core also has inlet and outlet holes in the main plate sections for passage of the heat exchange liquids into and out of the core. The formed plates are in nested, sealed engagement with one another. The main plate sections of at least the first end plate and the at least one intermediate plate are spaced apart from respective adjacent main plate sections to form liquid flow passages. The second end plate is formed with an integral ridge extending snugly along and adjacent to the edge wall of the adjacent intermediate plate. At least one section of the ridge is spaced from an adjacent edge of the second end plate so as to provide at least one mounting flange for the heat exchanger.
In an exemplary version of this heat exchanger, the second end plate is made of substantially thicker metal plate than the rest of the formed plates.
According to still another embodiment of the invention, an oil heat exchanger for heat exchange between oil and a heat exchange liquid comprises a heat exchange unit formed of a plurality of dished plates connected together in a sealing manner and arranged in a stack. The stack includes first and second end plates and a plurality of intermediate plates. Each of the dished plates has a substantially planar, main plate section which is spaced apart from the or each adjacent main plate section of another dished plate to form a respective liquid flow passage. The main plate sections have inlet and outlet holes for separate passage of the oil and the heat exchange liquid into and out of the liquid flow passages. The second end plate is formed with an integral ridge extending snugly along, and around an edge wall of the dished plate adjacent thereto. Two or more sections of the ridge are each spaced from an adjacent edge of the second end plate so as to provide mounting flanges for the heat exchanger.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example only, with reference to the accompanying drawings in which:
FIG. 1 is a perspective view showing a heat exchanger base plate and core plate according to the prior art, without reinforcement;
FIG. 2 is an exploded view of a stacked heat exchanger according to the prior art, without reinforcement;
FIG. 3 is a cross-sectional side elevation schematically illustrating a stack of dished heat exchanger plates rigidly attached to a base plate with a belt reinforcement according to the prior art;
FIG. 4 is a perspective view similar to FIG. 1 but showing a base plate and an attached core plate constructed according to one embodiment of the invention;
FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 4;
FIG. 6 is a perspective view of the base plate and adjacent core plate shown in FIG. 4 with both plates shown cutaway so as to show their transverse cross-sections;
FIG. 7 is a perspective view similar to FIG. 4 but showing an alternate form of base plate only;
FIG. 8 is a plan view of the base plate of FIG. 7;
FIG. 9 is a cross-sectional view similar to FIG. 5 but showing an alternate form of baseplate which also functions as a core plate; and
FIG. 10 is a vertical cross-section similar to FIG. 3 but showing another embodiment of dished plate heat exchanger with a base plate formed with an integral ridge.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
In the detailed description which follows, various exemplary embodiments are described, particularly with reference to the appended figures. However, the particularly disclosed embodiments are merely illustrative of heat exchangers constructed according to the present disclosure.
Referring now to FIG. 1, a conventional heat exchanger plate 10, according to the prior art, comprises a rectangular plate bottom 12 surrounded on all sides by an upwardly and outwardly sloping edge wall 14. The plate 10 is fixedly mounted on a substantially rectangular base plate 11. The bottom 12 constitutes a central main section of the plate 10 having a peripheral edge 16. The edge wall 14 extends outwardly from and around this peripheral edge at an acute angle indicated at A to a plane defined by the main plate section and the base plate 11. A heat exchanger plate of this type is commonly known as a “dished” plate. The illustrated bottom 12 is provided with four holes 18, 20, 22, and 24 near its four corners, each of these holes able to serve as an inlet hole or an outlet hole for a heat exchange fluid as required by the particular application. Two holes 18 and 24 are raised relative to the plate bottom 12 and are formed in raised bosses having flat upper surfaces 26 and 28 and circumferential sidewalls 30 and 32. As can be seen from FIG. 1, the raised holes 18 and 22 are spaced from the edge wall 14. The other two holes 20 and 22 are co-planar with the bottom 12. As shown, the hold 24 can be effectively closed by the base plate if no fluid passage is required at this location. If desired or if required, the plate 10 can be attached by brazing to the base plate by means of a flat shim plate 13 in a known manner. The shim plate, which initially can be coated with a brazing material, can be approximately the same in size and shape as the central main section of the plate 10.
A plurality of plates of the type shown in FIG. 1 can be stacked on top of one another to form a stacked plate heat exchanger as shown in FIG. 2. It will be understood that a plurality of dished-type plates such as the plates 10′ can be arranged in a stack to form a heat exchanging core with fluid flow passages being provided between adjacent plates in the stack. As illustrated, the plates 10′ are stacked with their edge walls 14′ in nested, sealed engagement. The raised holes 18′, 24′ of plate 10′ align with the two flat holes and the flat upper surfaces 26, 28 of the raised holes 18′, 24′ are sealed to the bottom of an adjacent of plate 10′ around the peripheries of the flat holes including hole 22′. A flow passage for heat exchange fluid is formed between the plate bottoms 12′ of plates 10′. In order to enhance heat exchange efficiency, a fin or turbulizer 27 of known construction may be provided in this flow passage. Also shown in FIG. 2 are a suitable metal reinforcement plate 29, a lid plate 31 having no fluid flow holes and closing the top of the upper core plate 10′, and a flat shim plate 13′ connecting the core to the base plate 11′.
FIG. 3 illustrates schematically a known method for mounting a stacked plate heat exchanger. The heat exchanger 40 comprises a heat exchanging core formed of a plurality of dish-type or dished plates 42 arranged in a stack with fluid flow passages 44 being provided between adjacent plates in the stack. As in the embodiment illustrated in FIG. 1, each plate 42 comprises a main plate section or bottom 12 and an edge wall 14 extending outwardly from and around the peripheral edge of the bottom. For ease of illustration, the inlet and outlet holes provided through the bottoms of the plates are not shown in FIG. 3. In this heat exchanger, the heat exchanging core is supported by a base plate 46 which is rigidly attached to one of the dish-type plates 42 located at one end of the stack (as shown in FIG. 3, this is the bottom plate 42′). Strengthening the connection between the adjacent or bottom core plate and the base plate is a so-called belt 48 which extends about the periphery of the adjacent plate 42′. Instead of a belt connection to attach the core to the base plate, it is also possible to use a shim plate as shown in FIGS. 1 and 2 or a double core plate. A “double core plate” is a construction wherein the end of the heat exchanger core is made of two core plates arranged immediately next to each other both along their central main sections and along their edgewalls and rigidly connected together. The use of the belt or a double core plate (not shown) strengthens the weakest location of this type of heat exchanger. In other words, the weakest location of this type of heat exchanger is generally the connection to the first or bottom core plate 42′ when this particular core plate does not have a double thickness relative to the other core plates 42. However, a difficulty with a double core plate or a belt is that it increases the amount of material used in the construction of the heat exchanger compared, for example, to the use of a shim plate. Also, belts such as the belt 48 can be difficult to manufacture and relative costly as the stamping angle is greater than 90 degrees, which means that these belts need to be stamped in two directions. It will also be appreciated that these belts are generally made from a single, flat metal plate with the center portion of the plate being removed and not used. Thus, the amount of metal required to make the belt is quite high.
As also shown in FIG. 3, the known base plate 46 is generally relatively thick, particularly when compared to the thickness of the core plates 42. The base plate has been made thick in order to increase the rigidity of this plate, which increases the strength of the connection between the plate and the core. However, the use of a thick base plate increases the overall weight of the heat exchanger and, of course, increases the amount of material used in the construction of the heat exchanger.
FIGS. 4 to 6 illustrate the construction of a bottom section of a heat exchanger constructed in accordance with the present invention. This bottom section includes a bottom end plate 43′ which is at one end of a heat exchanging core formed of a plurality of the dish-type plates 43 arranged in a stack with the fluid flow passages 44 being provided between adjacent plates in the stack. Only the end plate 43′ and the adjacent plate 43 are shown for ease of illustration. The core is of known construction. Each dished plate has a bottom or main plate section 12 having a peripheral edge 16 and an edge wall 14 extending outwardly from and around the peripheral edge at an acute angle to the plane defined by the bottom or main plate section. The inlet and outlet holes 18, 20, 22, 24 can be provided through the main plate sections of the plates for passage of heat exchange fluids. If, for example, the heat exchanger 10 is intended as an oil heat exchanger, one of the heat exchange fluids can be oil or a similar liquid while a second heat exchange fluid can be an standard, known liquid used for cooling (or heating) oil. The plates 43, 43′ are in a nested seal engagement with one another and the main plate sections of adjacent plates are spaced from one another to form the fluid flow passages 44.
In order to mount the heat exchanger 50, there is provided a metal base plate 54. In an exemplary version of the heat exchanger, the plate 54 is substantially thicker than core plates 43, 43′. The normal range of base plate thickness is between 1.5 and 4 mm (0.060″ to 0.160″). The base plate 54 is rigidly attached to the dish-type plate 43′ which is at one end of the stack. The base plate is formed with an integral ridge 56 extending snugly along and adjacent the edge wall of the dish-type plate 43′. Sections of the ridge 56 or the entire ridge are spaced from adjacent edges 58, 58′ of the base plate so as to provide mounting flanges 60, 60′ for the heat exchanger. The base plate 54 can be made by a stamping process.
The ridge 56 in an exemplary embodiment can have a U-shaped transverse cross-section as shown in FIGS. 5 and 6. When the plate 54 is formed by stamping, there is a minimum bending radius for the plate. For aluminum, this minimum bending radius is usually 1× thickness of the plate. The ridge includes inner ridge wall 62 and outer ridge wall 64, with these two walls in the illustrated exemplary version extending at an acute angle to each other and to the vertical as seen in FIG. 5. The inner ridge wall 62 extends parallel to an adjacent outer surface 66 of the edge wall of the adjacent core plate 43′ and is attached directly thereto by brazing.
The illustrated exemplary ridge 56 is a continuous ridge that extends around the perimeter of the end core plate 43′, this continuous ridge being shown in FIG. 4. Thus the ridge has two parallel, opposite sections 68 and 70, and two further parallel and opposite sections 72, 74. However, instead of the continuous ridge as shown, the heat exchanger can be formed with simply two ridge sections, for example, locked on opposite sides of the end core plate 43′. It is also possible to construct the base plate with several, separate ridge sections which are not joined to one another, for example, one section on each corner of the end core plate 43′. For some applications, the ridge may extend along only one side of the heat exchanger, providing only one mounting flange located on one side of the heat exchanger.
FIGS. 4 and 6 also illustrate fastener holes 80 formed in the mounting flange or flanges. Bolts or rivets can extend through these holes for the purpose of mounting the heat exchanger to an adjacent support structure (not shown). Two such bolts 82 can be seen in FIG. 4. It will be appreciated that such holes can be provided in all four corners of the base plate in an exemplary embodiment. Depending on packaging issues and depending on the sealing requirements of the base plate 54, the mounting flanges can be displaced from the corners of the plate. In most cases there are 3 to 5 holes 80 around the perimeter of the base. Threaded fasteners in the form of screws can also be used instead of bolts and nuts.
It will be appreciated that a very strong, permanent connection can be formed between the base plate 54 and the adjacent core plate, particularly by means of brazing, a technique for connecting stacked plates well known in the heat exchanger art. The brazed connection is formed not only along the inner ridge wails and the adjacent edge walls of the core plate but also between the central main plate section 84 of the base plate and the central main plate section of the end core plate.
An exemplary base plate 54 is made of 3003-aluminum. Other possible aluminum materials for the base plate are 3000 series, 5000 series and 6000 series, such as 6061. When the base plate 54 is formed by a stamping process, the process only requires stamping in one direction. With the present mounting, the base plate can be a relatively thin plate if desired (see FIG. 9). When the base plate is made of a thinner material, both the weight of the base plate itself is reduced and the weight of the complete heat exchanger. The formation of the continuous ridge on the base plate increases the rigidity of the base plate.
FIGS. 7 and 8 illustrate another embodiment of a base plate for a stacked plate heat exchanger with an exchanger core formed of a plurality of dished plates 43, 43′ such as those shown in FIGS. 4 to 6. The base plate 94 which has an integral ridge 56 formed thereon similar to the base plate 54 of FIG. 4. In addition, formed along two side edges of the base plate is a peripheral lip or rib 96 which provides additional rigidity to the base plate. It will be understood that this lip can extend about the entire periphery of the base plate, if desired or it can be provided on one or three side edges if this will provide the necessary rigidity. The peripheral lip 96 as shown extends substantially perpendicular to the plane defined by the planar central section of the base plate. However, it is possible for the peripheral lip to extend at a different angle from that shown. For example the lip can extend at an acute angle to the adjacent flange section of the base plate. Instead of using a lip 96, the base plate can also be strengthened by using an additional U-shaped ridge similar to the ridge 56 or a V-shaped ridge (see FIG. 9 for example). FIGS. 7 and 8 also illustrate the provision of fluid flow holes 95, 97 and 99 in the central section of the base plate which can be inlet and outlet holes for the heat exchange liquids (i.e. oil, coolant). Note that four holes are required in the overall heat exchange for the inlet and outlet for the first liquid (for example, oil) and for the inlet and outlet for the second liquid (for example, coolant). Each of these holes can be either in the base plate or the top plate, depending on the packaging. In the case of an engine oil heat exchanger, the oil or coolant sometimes comes from galleries inside the engine directly to the base plate. In other cases, the oil and/or coolant flows through hoses to a fitting located on the top plate or sometimes the base plate.
A further embodiment of heat exchanger formed from a stack of dished plates is illustrated in FIG. 9. This heat exchanger 100 is similar to the heat exchangers desired above in connection with FIGS. 4 to 6 except for the differences explained hereinafter. The main portion of its core 92 is formed of a series of similar or identical dished plates 43. The base plate 102 is formed from thicker metal plate which can, in an exemplary embodiment, be aluminum alloy. In this embodiment, the plate 102 also provides a first core plate for the heat exchanger. Thus, there is a fluid flow passage 44 formed between the plate 102 and the adjacent core plate 43. With this embodiment, there is still a saving of material since the base plate also provides the first core plate. An integral ridge 110 similar to that in the embodiments of FIGS. 4 and 6 is provided on the base plate and it can be brazed to the edge wall of the adjacent plate 43. However, the ridge 110 has a V-shaped cross-section throughout its length as shown. The V-shape is inverted when the base plate is positioned at the bottom of the heat exchanger as shown. If desired and, in order to strengthen the connection between the base plate and the adjacent plate 43, the height of the inner ridge wall 111 can be increased so as to extend the entire height of the adjacent edge wall.
FIG. 10 illustrates yet another embodiment of a heat exchanger constructed in accordance with the present disclosure. This heat exchanger 120 is also formed of a stack of dished plates 43 and has a base portion similar to that illustrated in FIGS. 4 to 6 except for the differences noted hereinafter. Its base plate 122 is formed from a relatively thin metal plate which can, for example, be similar in thickness to the dished plates. One exemplary material for the base plate 122 is 3003-aluminum. The bottom end plate 43′ which is at one end of the heat exchanging core is rigidly attached such as by brazing to the base plate. In this embodiment, the base plate is formed with an integral V-shaped ridge 124 which extends along and is immediately adjacent to the edge, wall of the dish-type plate 43′. Again sections of the ridge or the entire ridge are spaced from adjacent edges 124, 126 of the base plate so as to provide mounting flanges for the heat exchanger. In a particular exemplary embodiment (and as better shown in FIGS. 4 and 6) the mounting flanges are provided at the corners of the base plate.
Although the core plates 43, 43′ are shown with substantially flat, central main plate sections, it will be understood by those skilled in the heat exchanger ah that the main plate sections can be provided with ribs, corrugations, dimples or other protrusions to enhance heat exchange efficiency by forcing the heat exchange fluid to flow a tortuous path through the fluid flow passages 44.
It will also be understood that it is possible to construct the heat exchangers of the present invention by means of a single brazing step after the core plates are stacked together with the base plate. Thus, these heat exchangers can be manufactured in an efficient manner and at a reasonable cost.
The heat exchanger construction described herein can also be used for stainless steel heat exchangers, whether copper or nickel brazed. In such heat exchangers, the base plate can be made of stainless steel or steel. One form of stainless steel that can be used is 304 SS.
While the present invention has been illustrated and described as embodied in several exemplary embodiments, ie. embodiments having particular utility in heat exchanger applications, it is to be understood that the present invention is not limited to the details shown herein, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the disclosed heat exchangers and their operation may be made by those skilled in the art without departing in any way from the spirit and scope of the present invention. For example, those of ordinary skill in the art will readily adapt the present disclosure for various other applications without departing from the spirit or scope of the present invention.
Patent Application
20110024095
