Patent Application
20130098590
1. Field of the Invention
The present invention relates generally to heat exchangers and, more specifically, to a heat exchanger having plurality of disk assemblies coupled to a plate member, each disk assemblies having a tube and a chamber apparatus, said chamber apparatus having a medium directing member within for transporting heat exchange medium.
2. Discussion of the Related Art
Heat exchangers are commonly utilized in systems where it is desired for heat to be removed. Typical basic heat exchangers are made of pipes, which channel heat exchanging medium. Headers or manifolds are attached to each end of the pipes. These headers and manifolds act as receptacles for the heat exchanging medium. The efficiency of the pipe heat exchangers is limited by the amount of surface area available for the transfer of heat. In a tube and chamber heat exchanger, plurality of tube and chamber extend in spaced relation between a pair of header or manifold, forming a core of a heat exchanger. The present invention provides an effective and efficient means to increase surface area to a core of a tube and chamber heat exchanger, which in turn greatly enhances the performance of a heat exchanger performance with a simple solution. The present invention achieves these enhancements without adversely affecting the overall size of the core, while simplifying the manufacturing process, thereby providing a heat exchanger with vastly improved heat exchanging characteristics without adverse cost impact.
To increase surface area, typical heat exchangers, such as condensers, incorporate a flat-tube design, usually of extruded tubular material, with extended surfaces provided by corrugated fin material. This type of heat exchanger typically includes flattened tubes having a fluid passing therethrough and a plurality of corrugated fins extending between the tubes. The fins are attached to the tubes to effectively increase the surface area of the tubes, thereby enhancing heat transfer capability of the tubes. A number of tubes and fins may be stacked on top of each other, which leaves a small opening to allow passage of air in between them. To further improve heat transfer efficiency, the tube thickness is made thinner. As a result, the parts are lighter in weight, which in turn makes the overall heat exchanger lighter in weight. However, the pressure resistance is reduced, and the thinner tubes are more prone to damage. Also, the assembly process is complicated because of the fragile nature of the parts. In addition, the extruded tubes are prone to plugging during the manufacturing process, particularly if a brazing process is utilized. The complexity of the extruding process potentially results in higher costs and higher defect rates.
The overall cost for the flat tube heat exchanging system will be higher because a higher powered compressor may be necessary to move the heat exchanging medium through the smaller openings of the tubes. Conversely, if a higher powered compressor is not utilized, then additional tubes will be necessary to obtain the desired heat exchanging performance because the smaller tubes reduce the flow of the heat exchange medium significantly. The additional tubes will increase the overall cost for the heat exchanging system. Currently, this type of heat exchanger is used in applications requiring high heat exchanging capabilities, such as automotive air conditioner condensers.
In another tube-and-fin design, the tube can be of a serpentine design, therefore eliminating the need for headers or manifolds, as the tube is bent back and forth in an “S” shape to create a similar effect. Typical applications of this type of heat exchanger, besides condensers, are evaporators, oil coolers, and heater cores. This tube-and-fin design is also utilized in radiators for automobiles. Outside of the automotive field, the tube and fin design is implemented by industrial oil coolers, compressor oil coolers, and in other similar applications requiring a higher efficiency heat exchanger.
A variation on the tube-based heat exchanger involves stacking flat ribbed plates. When stacked upon each other, these ribbed plates create chambers for transferring heat exchanging medium. In essence, this type of heat exchanger performs substantially the same function as tube-and-fin type heat exchangers, but is fabricated differently. This type of heat exchanger is commonly implemented by contemporary evaporators.
In a typical manufacturing method of tube and fin heat exchangers, plurality of fins are first stacked to a desired quantity. Once fins are bound and stacked together, tubes are inserted into plurality of holes pre-formed on each fin. Holes pre-formed on fins are arranged so that once the fins are bound together, the holes align with each other from the first fin material to the second fin material, allowing a generally straight tube to be inserted through the holes. In order to enhance the heat transfer characteristics, once tubes and fins are assembled together, individual tubes go through an expansion process whereby tubes are expanded from within by mechanical means to increase the diameter of tubes, enhancing the tube to fin surface contact. To facilitate the tube expansion process, at least one free end of tubes is left open to allow the tube expansion device to be inserted, once the tube and fin structure are assembled together. Upon completion of the tube expansion process, open end of tubes are sealed, usually by means of a manifold.
In a manufacturing process of flat tube heat exchangers, tubes are first cut to a desired length. In a separate line, fins are corrugated and fabricated to a desired shape, then cut to a desired length. Once tubes and fins are ready for assembly, plurality of tube and fin material is stacked together, with fin material coupled between two tubes aligned parallel to each other. Once tube and fin material is stacked together to a desired height, manifolds are assembled onto the free ends of the tubes. In assembling all the components together, a precision assembly fixture is generally required, as tube and fin material are prone to come apart during the assembly process, until the entire assembly is processed through a brazing process, a process which bonds all components together. Especially during the assembly of manifolds onto the free ends of the tubes, tubes need to be held in position firmly by an assembly fixture for a proper assembly. Due to the nature of the flat tube heat exchanger assembly, if the assembly fixture is even slightly off tolerances, the entire heat exchanger assembly may not braze properly. For this type of heat exchanger assembly, significant investment must be made in precision assembly machines and fixtures, in addition to having components made to a very high-precision tolerances, causing the assembly cost of a heat exchanger to rise significantly, in addition to having to pay more for precision made components.
The present invention is an enhanced tube for heat exchanging applications including flow tube and a chamber coupled to a generally planar plate member. The flow tube connects to the chamber. One end of the flow tube may connect to a header or a manifold. Heat exchange medium flows from the header or the manifold into the flow tube. The heat exchange medium then flows into the chamber. The chamber is coupled to a plate member. The heat exchange medium then flows from the chamber into another flow tube, which is connected to another header or manifold. The heat contained within the heat exchange medium is dispersed by a surface area of the flow tube, the chamber, and the plate member.
In an embodiment of the present invention, the flow tube, the chamber, and the plate member for a heat exchanger are provided, for example, for a condenser, evaporator, radiator, etc. The heat exchanger may also be a heater core, intercooler, or an oil cooler for an automotive application (i.e., steering, transmission, engine, etc.) as well as for non-automotive applications. An advantage of the present invention is that the heat exchanger has larger surface area for radiating heat over a shorter distance than that of a conventional heat exchanger, with the surface area provided by the flow tube and the chamber, along with extended heat exchanging surfaces provided by the plate member. With a provision of a large surface area for heat exchanging purposes, the efficiency of a heat exchanger is greatly increased. Another advantage of the present invention is that the overall length and weight of the enhanced tube for heat exchanging applications may be less compared to a conventional heat exchanger, which in turn provides for a lower overall cost as less raw material and less packaging is necessary. Additionally, the flow tube and the chamber may be made from a thicker gage material, while the plate member may be made of thinner gage material. This allows the flow tube and the chamber to handle heat exchanging medium requiring higher internal pressure, which may be common in applications such as a condenser for an air conditioner, for example. Usage of thin gage material for the plate member improves heat conductivity of the plate member, while significantly increasing the surface area for heat exchanging purposes, without adversely affecting cost or the weight. Furthermore, the smaller footprint of the present invention lends itself to be used in applications where space is limited. Yet another advantage of the present invention over a conventional heat exchanger is that the manufacturing process may be simpler because the present invention requires less fragile components and less manufacturing steps. Furthermore, during the assembly process, the plate member on which flow tube and chamber are coupled to, assists in positioning the flow tube and the chamber assembly, acting akin to an assembly tray during the manufacturing process, holding in place components during the assembly process. The entire unit may be brazed together, or any portion of the unit can be brazed first, and then additional components may be brazed or soldered together.
In another embodiment of the present invention, more than one chamber may be used, which will further increase the surface area of the enhanced tube for the heat exchanger. Also, a first chamber may be connected directly to another chamber. Furthermore, more than one chamber may be coupled to a plate member. In another embodiment of the present invention, more than one plate member may be coupled to a chamber. When plurality of chambers are coupled to the plate member, the plate member provides an economical means to maximize the heat exchanging capability of a heat exchanger by filling the voids between plurality of column of chambers to increase the overall surface area of the heat exchanger, without greatly increasing the size of a heat exchanger.
In yet another embodiment of the present invention, the tube size may vary between the chambers, and if more than one chamber is used, the chamber size may vary from one chamber to the next.
In another embodiment of the present invention, plurality of tube size and chamber size positioned on a plate member may vary from one to the next.
In a further embodiment of the present invention, each chamber may disperse heat exchanging medium throughout the chamber, which further enhances the heat exchanging capabilities of the present invention. Also, each chamber may also mix heat exchanging medium.
In yet a further embodiment of the present invention, each chamber may include a medium-directing member and medium redirection members that direct and redirect heat exchanging medium in a particular directions through the chamber.
In another embodiment of the present invention, the inner surface of the tube may feature indentations to increase the surface area. Also, in yet another embodiment of the present invention, the inner surface of the chamber may also feature indentations to increase the surface area. In a further embodiment of the present invention, the medium-directing member may also feature indentations. In an embodiment of the present invention, the plate member may have surface features such as, but not limited to, indentations, louvers, dimples, slits, other extended surface features known in the art, etc.
In other embodiments of the present invention, the tube, the chamber, and the plate member combination may be repeated, and based on a particular application, there may be multiple tube, chamber, and plate member assembly rows coupled together to form a unitary unit. Plurality of tube, chamber, and plate member units may be attached to a header or a manifold. There may be a plurality of tube, chamber, and plate member units arranged in a row that are attached to a header or a manifold to enhance the overall performance of the heat exchanger.
In some embodiments, the chamber is of a greater diameter than the inlet and the outlet of the chamber. In other embodiments, the chamber is of a greater diameter than the inlet of the chamber, but may be the same diameter as the outlet. Alternatively, in yet other embodiments, the chamber may be of a greater diameter than the outlet of the chamber, but may be the same diameter as the inlet.
In an embodiment of the present invention, the plate member may be rectangular in shape. In other embodiment of the present invention, the plate member may be other geometric shape like a trapezoid or an oval, for an example. In some embodiments of the present invention, the plate member may have surface feature such as plurality of folds or bends that rise generally perpendicular from the surface of the plane of the plate member to assist in spacing plurality of plate member from one plate member to the other. In such an embodiment, the apex of a fold or a bend from first plate member abut against the base plane of second plate member, whereby the height of a fold or a bend dictate the spaced relation between the first plate member and the second plate member.
In yet some other embodiments, the chamber has at least one greater dimension than the tube. For instance, the chamber may have a greater fluid capacity, circumference, or surface area. The ratio of a particular dimension between the tube and the chamber may be 1:1.1; 1:1.5; or any other suitable ratio.
In an embodiment of the present invention, the plate member has an indentation in the shape of the chamber, coupling the chamber in position within said indentation on the surface of the plate member. In another embodiment of the present invention, the plate member has plurality of indentations in the shape of the chamber, the plate member coupling plurality of chambers. In such an embodiment, chamber coupling locations are dictated by the position of indentations on the surface of the plate member.
In some embodiment of the present invention, a chamber assembly comprising of the inlet and the outlet flow tubes, the chamber, and the medium-directing member may be assembled as a unit, then coupled to the plate member. In an embodiment of the present invention, plurality of chamber assemblies may be coupled to the plate member.
In yet another embodiment of the present invention, the plate member has a hole formed in the shape of the chamber, positioning and locating the chamber on the plate member. In another embodiment of the present invention, the plate member has a plurality of holes in the shape of the chamber, to which chambers are coupled.
In some embodiment of the present invention, the plate member has a hole in the shape of the tube, onto which the tube is inserted for the purpose of holding the tube in position on the plate member. In another embodiment of the present invention, the plate member has a plurality of holes in the shape of the tube. In yet another embodiment of the present invention, the plate member may contain plurality of holes in the shape of chambers and tubes, whereas some of the holes are for coupling chambers, and some of the holes are for coupling tubes.
In another embodiment of the present invention, the plate member may contain plurality of indentations in the shape of chambers, each indentations having a hole to pass through the tube, wherein indentations are used to couple chambers to the plate member.
The tube and the chamber may be made of aluminum, either with cladding or without cladding. The plate member may be made of aluminum, either with cladding or without cladding. The medium-directing member may be made of aluminum, either with cladding or without cladding. The tube, the chamber, the medium-directing member, and the plate member may also be made of stainless steel, copper or other ferrous or non-ferrous materials. The tube, the chamber, the medium-directing member, and the plate member may also be a plastic material or other composite materials.
The tube, the chamber, the medium-directing member, and the plate member may be manufactured by stamping, cold forging, casting, or machining. The tube and the chamber may be manufactured as one piece or may be manufactured as two separate pieces. The tube, the chamber, and the plate member may be manufactured as one piece, or may be manufactured as separate pieces. The chamber and the medium-directing member may be manufactured as one piece, or may be manufactured as separate pieces.
Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood after reading the subsequent description taken in conjunction with the accompanying drawings.
Referring to the drawings and in particular
In another embodiment of the heat exchanger 105, the heat exchanger 105 may be used in a reversed method. Instead of the heat exchanger 105 being used in an environment where heat is transferred from the heat exchange medium 15 to the surrounding environment of the heat exchanger 105, the heat exchanger 105 may be used to increase the temperature of the heat exchange medium 15 flowing inside the present invention. For example, a refrigerant with a low boiling temperature may flow through the tube 20 and the chamber 30 of the heat exchanger 105, where the environment surrounding the heat exchanger 105 is of a higher temperature than that of the refrigerant. Continuing with this example, the heat from the environment surrounding the heat exchanger 105 is transferred to the refrigerant, thereby increasing the temperature of the refrigerant, hot enough to cause the refrigerant to reach a boiling temperature. An example of this embodiment, which is not intended to be limiting, would be an evaporator for an air conditioning unit.
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Other embodiments of the present invention are illustrated in
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The tube 20 embodiments may be mated in various combinations with the chamber 30 embodiments. Additional fin material may be coupled to the inside or the outside of the tube 20. Additional fin material may be coupled to the inside or the outsize of the chamber 30. The plate member may have performance enhancing surface treatment. The plate member may have louvers, slits, or additional extended surface features known in the art to improve the heat exchange characteristics of the plate member 35. Other embodiments of the tubes, chambers, and plate members not pictured may also be combined, and the invention is not limited to the embodiments described.
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The chamber generally has at least one greater dimension than the tube. For instance, the chamber may have a greater fluid capacity, circumference, or surface area. The ratio of a particular dimension between the tube and the chamber may be 1:1.1, 1:1.5, or any other ratio.
The tube and the chamber may be made of aluminum, either with cladding or without cladding. The tube and chamber may also be made of stainless steel, copper or other ferrous or non-ferrous material. The tube and chamber may also be a plastic material or other composite materials. Likewise, the medium-directing member may be made of aluminum, either with cladding or without cladding. The medium-directing member may also be made of stainless steel, copper or other ferrous or non-ferrous materials. The medium-directing member may also be a plastic material or other composite materials. The plate member may be made of aluminum, either with cladding or without cladding. The plate member may also be made of stainless steel, copper or other ferrous or non-ferrous material. The plate member may also be a plastic material or other composite material. Also, an embodiment of the present invention allows for the tube to be made of a different material than the material used for the chamber, and the medium-directing members may be made of a different material than the material used for the chamber, the tube, and the plate member. The material used for the plate member may be made of different material than the material used for the chamber, the tube, or the medium-directing member. If more than one medium-directing member is used in an embodiment of the invention, one medium-directing member may be made of a different material than another medium-directing member. The medium-directing members may also be of different shapes than one another. Also, if more than one plate member is used in an embodiment of the invention, one plate member may be made of a different material than another plate member. The plate member may also be of different shape than one another.
The tube, the chamber, the medium-directing member, and the plate member may be manufactured by stamping, cold forging, casting, or machining. The tube, the chamber, the medium-directing member, and the plate member may be manufactured as one piece or may be manufactured as two separate pieces.
The present invention has been described in an illustrative manner. The term “redirect” means to change the direction or course of, or impede the progress of, the heat exchange medium, even if by the smallest difference in angle or velocity. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.
Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced other than as specifically described.
