1. Field of Invention
The present invention relates to heat exchangers, specifically to a disk type heat exchanger unit with plurality of tubes and disk units for transporting heat exchange media within.
2. Discussion of the Related Art
There are various applications for heat exchangers where heat from one media is desired to be transported to another media. Typical heat exchangers are made of tubes with plurality of fin attachments on surface of tubes. Heat exchange media is transported through tubes, carrying heat within said heat exchange media. The heat transported through tubes by means of heat exchange media is transferred generally by means of conduction from heat exchange media to tube and fin structure of heat exchange assembly, as the heat exchange media flow through tubes. The tube and fin structure is surrounded by another heat exchange media, absorbing away heat from the tube and fin structure. The efficiency of a heat exchanger is generally dictated by the ratio of volumetric capacity of tubes to the overall surface area of tubes and fins. Typical application of this type of high performance heat exchangers are condensers and evaporators for use in commercial and residential air conditioner units. Variants of this type of heat exchangers are commonly utilized in commercial and automotive applications such as oil coolers, evaporators, condensers, heater cores, and radiators.
Efforts to enhance performance of heat exchangers is generally achieved by creating complex fin structures that have myriad bends and folds to create as much surface area within a given confine. Fins effectively increase surface area of tubes. In another effort to improve the performance, fins in addition to bends and folds may have plurality of louver features created on surface of fins. High performance heat exchangers are generally utilized where space is restricted, thus achieving higher performance with heat exchangers of smaller footprint. Enhancement efforts by means of utilizing complex fin structures may improve performance of heat exchangers, but potential additional manufacturing processes may adversely affect the total manufacturing cost of heat exchangers.
In another embodiment of this effort, instead of round tubes, flat tubes are made with plurality of small diameter holes. Generally of aluminum extrusion, intricate tubes are made with plurality of small diameter holes. To further improve performance of heat exchangers, thickness of a material used to create fins and tubes may be made thinner. By making the thickness of a material thinner, performance of a heat exchanger may be improved by shortening a distance that heat has to travel within walls of tube and fin structures, improving heat conduction efficiency. Thinning a material has the adverse effect of weakening a structure, however. Also, in an application such as automobiles where potential for debris hitting a heat exchanger surface is high, having a weak structure is not favorable, as a heat exchanger may be easily damaged, or worse having a puncture within tubes, causing heat exchange media within to leak out, rendering the heat exchanger useless. A manufacturing process of assembling together various heat exchanger components may be complicated as well, when components utilized are manufactured of thin walled tubes and fins. When components comprise of thin material, components are susceptible to damage during assembling process, requiring due care during assembly, typically raising manufacturing cost. Complication of manufacturing method typically has an adverse effect on the manufacturing cost, generally raising cost of individual components. Fragile components may also complicate handling of components during an assembly stage, as well as requiring stricter tolerance components as well as assembly machines capable of meeting strict tolerances, all of these factors typically resulting in higher component costs and assembly costs.
A variation on a tube-based heat exchanger involves stacking flat, ribbed plates. When said flat, ribbed plates are stacked upon each other, said plates create chambers for transferring heat exchanging media. In essence, this type of heat exchanger performs substantially in the same manner as tube-and-fin type heat exchangers, but is fabricated differently. This type of heat exchanger is commonly implemented by contemporary evaporators for automotive applications.
A variant of a disk type heat exchanger is described in Nitta, U.S. patent application Ser. No. 12/148,655 and Nitta, U.S. patent application Ser. No. 12/856,179 In theses embodiments, a heat exchanger core comprises of plurality of tube and chamber unit with a heat exchange media directing member disposed within. In these embodiments, a chamber is structurally supported by a heat exchange media directing member and a disk unit shell structure to prevent disk unit from deforming in high pressure application, such as for a condenser unit in an air conditioner application. The present invention improves upon these embodiments by having additional structural rigidity by means of connecting members connecting the second walls of the first disk member and the second disk member, providing additional structural rigidity to the disk unit, resisting the tendency for the disk unit walls to expand outwards when a chamber is supplied with heat exchange media under high pressure. The additional features in the present invention is beneficial in applications requiring high pressure environment for a heat exchange media, such as a condenser unit utilizing newer refrigerant, such as R-410, for example.
A first prior art example of a conventional tube and fin heat exchanger is described in Rhodes, U.S. Pat. No. 6,612,031. In this patent, an aluminum tube with multiple partitions within a tube is first extruded, and then cut into desired length. These tubes are then combined with additional fins, as tube surface alone is often insufficient and incapable of dissipating heat carried by a heat exchange media. Fins are sandwiched in between each row of tubes comprising a core of a heat exchanger. There are certain drawbacks to this type of heat exchanger cores. First, and foremost, tube extrusions with intricate inner partitions are very difficult to manufacture, requiring precision instruments to obtain a desired shape. Aluminum extrusion machines are typically utilized. An aluminum extrusion machine capable of manufacturing intricate extrusions are often very expensive machines, as well as being notoriously high in operating costs. The more intricate the extrusion shape, an aluminum extrusion machine's extrusion speed has to be reduced not only to obtained a desired shape, but also to protect an extrusion die, as complex extrusion shape causes the extrusion die to be very delicate, prone to damage. Due to the complex nature of extrusion machines, as well as slow operation and delicate extrusion dies that often break during operation, extruded tubes are sold at a relatively high cost, not to mention that there are only a handful of companies with extrusion machines capable of manufacturing intricate tube designs driving up costs. With tube and fin heat exchanger design, various components are combined together to form a heat exchanger core. These components are typically not designed to maintain its position in relation to each component in a standalone manner pursuant to a heat exchanger design parameters during an assembly process, prior to a brazing process which would braze together all components to form a unitary unit. As such, specialized assembly fixtures are often necessary during a manufacturing process to keep the parts together. As a fixture is critical in yielding a good working part, fixtures are often designed to close tolerances resulting in high cost. Also, as a fixture is needed for each heat exchanger assembled at a time, in a large manufacturing operations, where high volume of heat exchangers have to be manufactured at a time, a significant investment has to be made in fixtures, to have on hand enough sufficient quantity of assembly fixtures to support an assembly line. All these investments results in added costs to the manufacturing cost of tube and fin heat exchangers.
Fins utilized are generally of complicated design as described in a second prior art example of a conventional tube and fin heat exchanger in Hiramatsu, U.S. Pat. No. 4,332,293. In this patent, an aluminum tube is combined with corrugated fins to comprise a heat exchanger core. Fins discussed in this patent are corrugated to enhance performance of a heat exchanger. Corrugation is added to fins, as flat sheeted fins often do not yield a desired performance expectation. Therefore, fins are generally fabricated with corrugation feature at an additional fabrication cost and manufacturing processes.
A third prior art example of a conventional heat exchanger is commonly known as plate and fin heat exchangers described in Patel, U.S. Pat. No. 3,976,128. In this patent, instead of extruded tubes, individual tubes comprise of two formed plate halves, split along the long axis of the tube. By eliminating usage of extruded aluminum tubes, and by creating individual tubes by combining two formed plates, the main benefit is the cost savings, as formed plates are often less expensive to manufacture in comparison to aluminum extrusion tubes. As with tube and fin heat exchangers, however, tubes of plate and fin heat exchangers often do not have sufficient surface area in relation to the volumetric capacity of a tube assembly to dissipate heat carried by heat exchange media within, rendering a heat exchanger useless without additional surface area addition. In order to enhance performance of plate and fin heat exchangers, fin structures are sandwiched in between each row of formed plate tube structures to obtain added surface area to dissipate heat. There are certain drawbacks to this type of heat exchangers. First, and foremost, although the cost of components may be saved in comparison to extruded tubes, an assembly process of plate and fin heat exchanger remains similar to tube and fin heat exchangers, resulting in a complex assembly process often requiring a specialized assembly fixture to secure all components together until components are brazed together to form a unitary unit. The use of assembly fixture is often essential, driving up initial investment cost necessary to manufacture plate and fin heat exchangers, as significant investment has to be made in assembly fixtures for manufacture of specific configuration heat exchanger cores. Additionally, unlike extruded aluminum tubes, a plate and fin heat exchanger cannot be created with too much intricate details, as an assembly of two plate halves are often imprecise, and if a plate design is too intricate, the possibility of misaligning the two halves increase dramatically, rendering a completed heat exchanger useless. Therefore, plate and fin heat exchangers are commonly designed with larger inner partitions, typically resulting in lower performance than extruded aluminum tubes. Another common disadvantage with plate and fin heat exchangers is due to the nature of the design of stacking together plurality of plates without much opening between individual plates. With reduced opening between individual plates, a heat exchange efficiency from a heat exchanger surface to an atmosphere surrounding a heat exchanger, media such as air, is often poor, leading to a low efficiency heat exchanger performance.
The present invention is an enhanced heat exchanging apparatus with disk type heat exchanger core comprising of disk units having connecting members integrally of disk units to enhance structural rigidity in high internal pressure applications. A disk type heat exchanger core comprises of plurality of disk units. Disk units are formed by combining two disk members, a first disk member comprising first end of the disk unit, having an inlet formed as a tubular member on first side of the first disk member, and a second disk member comprising the other end of the disk unit, having an outlet formed as a tubular member on first side of the second disk member. The first disk member has connecting members generally surrounding the inlet of the first disk member on the second side of said disk member, an inlet flow path and an outlet flow path provided to allow passage of heat exchange media herein. In a preferred embodiment of the present invention, connecting members are integral component of a first disk member, formed as protrusion members on the second side of the first disk member. Generally, connecting members are formed on second side of the first disk member as protrusion members by forming the face of the second side of the first disk member by utilizing stamping dies, for example. The first disk member and the second disk member are coupled together on respective second side of said disk members creating a disk unit, top surface of connecting members on the first disk member engaging the second side of the second disk member. Generally, disk units are made of aluminum with cladding on one or both sides of a material. As such, connecting members, when the disk unit is processed through an operation such as a brazing process by which the clad material is melted to form a braze fillet, connecting members on the second side of a first disk member form a brazed joint between the first disk member and the second disk member, forming a strong union between the first disk member and the second disk member. By having a stepped surface on the second side of the first disk member as a result of having connecting members on the second side of the first disk member, a gap is formed between the respective second side of the first disk member and the second disk member, creating a chamber between the first disk member and the second disk member to allow flow of heat exchange media herein. Disposed within said disk unit is a heat exchange medium directing member. A heat exchange medium directing member is generally of a cylindrical member with first end of the generally cylindrical member end coupled to an inlet of the first disk member. Said first end of the heat exchange medium directing member has a channel cut into a face of the first end of said heat exchange media directing member, said channel cut at an angle generally between 30 to 45 degrees to facilitate flow of heat exchange media without much resistance. Second end of said heat exchange medium directing member also has a channel cut an angle, said channel cut at an angle generally between 30 to 45 degrees to facilitate flow of heat exchange media without much resistance.
In the present embodiment, heat exchange media first flows in to a disk unit through an inlet on a first disk member. The heat exchange media then flows through an inlet flow path provided as a pathway through connecting members on a second side of the first disk member, guiding the heat exchange media to a chamber within the disk unit. The heat exchange media when guided in to the chamber is directed substantially to one side of the chamber by a heat exchange media directing member. Once the heat exchange media flows into the chamber, the heat exchange media is guided towards the other end of the chamber, flow directed by the contour of the chamber wall. The second end of the heat exchange media directing member also has a channel cut at an angle on a side typically diagonally opposite from the channel on the first side, to facilitate flow of heat exchange media herein. The heat exchange media that was introduced into the disk unit from the disk inlet on the first disk member that has then flowed in the chamber, following the wall contour of the chamber is then drained out of the disk unit through the outlet formed on the second disk member. The heat exchange media is directed towards the outlet on the second disk member from the chamber by the outlet flow path provided as a pathway through connecting members on the first disk member. The heat exchange media is then led to the outlet on the second disk member by the heat exchange media directing member disposed within the disk unit. Plurality of said disk units may be coupled together to form a single unitary unit. When one or more disk units are combined to form a single unit, an outlet of a first disk unit may be coupled to an inlet of a second disk unit. This arrangement is repeated as needed to obtain a unitary unit with a desired disk unit quantity. One end of said single unitary unit of plurality of disk units may be coupled on one end to a first header or a manifold. The other end of said unitary unit of plurality of disk units may be coupled to a second header or a manifold member. Plurality of said unitary unit of plurality of disk units may be coupled on first end with a first manifold member, and second end coupled with a second manifold member. One or more baffles may be disposed within first and second manifold to facilitate desired heat exchange media flow pattern.
In another embodiment of the present invention, connecting members on a second side of a first disk member may not be an integral component of the first disk member, but in a form of separate components, a connecting members formed in a desired shape to facilitate connection between the first disk member and the second disk member. In this embodiment, connecting members are not integrally formed on the second side of the first disk member, but similarly functioning separate components are inserted within the disk unit to serve as structural connections between the second side of the first disk member and the second side of the second disk member. Said separate connecting member may comprise of cladded material, allowing for said members to form a strong joint by means of a brazing process. Said cladded material in a preferred embodiment would be a double sided clad material. However, in another embodiment, if disk units themselves are cladded material, with the clad side on respective second side of the first disk member and the second disk member, connecting members may not be cladded material.
The present invention is also a method of making a disk type heat exchanging apparatus. The method includes the steps of providing a first generally planar material having a tubular member formed on first side of said material, creating an inlet on the material. The method includes a step of forming said material by cutting out a desired shaped disk member, removing away excess material, creating a first disk member. The method includes a step of forming connecting members on second side of said material. Said connecting members formed by plurality of folds on the second side of said material, said folds created by utilizing stamping dies comprising of a top die and a bottom die that when pressed together yields a desired shape. The method includes the steps of providing a second generally planar material having a tubular member formed on first side of said material, creating an outlet on the material. The method includes the step of forming said second material by cutting out a desired shaped disk member, removing away excess material, creating a second disk member. The method further includes the step of making an annular bend on the outer edge of said second material forming an annular wall projecting outwardly from the second side of said material. The method includes the steps of providing a generally cylindrical material, said material having a channel cut at an angle on both ends, creating a heat exchange directing member. The method further includes the steps of disposing said heat exchange medium directing member, first end of the heat exchange medium directing member engaging the inlet of the first disk member, second end of said heat exchange medium directing member engaging the outlet of the second disk member. The method further includes the steps of coupling said first disk member and second disk member, connecting members on the first disk member engaging the second side of the second disk member, creating a chamber between the respective second side of first disk member and the second disk member, forming a disk unit. The method includes the step of bending the annular wall on the second disk member onto the first disk member, coupling the first disk member and the second disk member together. The method further includes steps of coupling plurality of said disk units, outlet of a first disk unit engaging an inlet of a second disk unit.
In an embodiment of the present invention, the method includes providing first material and second material that are generally planar sheet material, formed into desired shape by stamping said materials, an inlet on the first material and an outlet on the second material formed by forming said materials. The method further includes placing connecting members between the second sides of the first material and second disk material, disposed generally around the inlet of the first material. The method further includes a step of creating a generally annular bend on the outer periphery of the second material, made generally perpendicular from the second face of said material, forming an annular wall projecting outwardly from the second side of said material. The method includes the steps of coupling said first material and said second material on respective second side of materials, first face of connecting members engaging the second side of the first material, and second face of connecting members engaging the second side of second material. As the connecting members are disposed between the second side of first material and second material, a gap is formed between the second side of the first material and the second side of second material where connecting members are not present, forming a chamber. The method further includes the steps of bending the annular wall on the second material on to the first side of the first material, coupling said materials together, forming a disk unit. The method further includes the steps of providing a generally cylindrical material, said material having a channel cut at an angle on both ends, creating a heat exchange medium directing member. The method further includes the steps of disposing said heat exchange medium directing member in the disk unit. The method further includes the steps of coupling plurality of said disk units, outlet of a first disk unit engaging an inlet of a second disk unit.
In another embodiment of the present invention, the first material and second material may be formed by machining said materials, removing away excess material from said materials until a desired shape is achieved.
In an embodiment of the present invention, disk type heat exchangers 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 various applications. An advantage of the present invention is that the heat exchange media is introduced into a chamber within individual disk units, thereby increasing the surface area that a heat exchange media comes in to contact within a heat exchanger, improving the efficiency of heat exchangers. Conventional heat exchangers, wherein heat exchange media flows in a generally round tube, heat exchange media flows in layers, carrying varying amount of heat within each layer. In such an arrangement, heat exchange media closest to a tube surface may more effectively transfer heat from heat exchange media to the tube surface. However, heat exchange media closer to center of the tube may be less efficient at transferring heat on to the tube surface, as heat has to travel through different layers of heat exchange media generally by conduction, in order to reach the tube surface. In comparison, present invention improves heat transfer efficiency of heat exchange media by spreading out the heat exchange media in a chamber, thereby increasing the heat exchange media to heat exchanger surface contact, increasing heat transfer efficiency. A chamber also has an added benefit of reducing the distance heat has to travel within heat exchange media thereby improving heat exchange efficiency, as spreading the heat exchange media flat and thin has an added benefit of creating a thinner layer of heat exchange media. Another advantage of the present invention is that a heat exchange media directing member coupled within a disk unit effectively routes heat exchange media to contact heat exchanger surface more effectively. A heat exchange media directing member also has an added benefit of effectively mixing and stirring heat exchange media within a disk unit chamber preventing laminar flow of heat exchange media, thereby increasing heat exchange efficiency. As heat exchange efficiency is improved in the present invention, overall size of a heat exchanger may be made smaller compared to a conventional heat exchanger of equal capacity, which in turn provides for a lower overall cost as less raw material and less packaging is necessary. 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 a manufacturing process may be simpler because the present invention requires less fragile components and less manufacturing steps. Conventional heat exchangers typically require extensive investment in preparing assembly fixtures, as various components may fall out of place during assembly without assembly fixtures. Furthermore, conventional heat exchangers require new assembly fixtures to be created for each heat exchanger core design change, even if component level parts remain the same. The present invention improves upon conventional heat exchanger manufacturing process, as entire unit may be brazed together, or any portion of the unit may be brazed first, and then additional components may be brazed or soldered together without use of assembly fixtures if necessary, significantly reducing an investment in assembly fixtures.
In another embodiment of the present invention, tube size may vary between disk units. A disk unit size may vary from one disk unit to the other.
In yet another embodiment of the present invention, to further enhance the performance, additional fin material may be added to disk units.
In a further embodiment of the present invention, each media directing member inside a disk unit may be rotated at a predetermined angle from each other.
In another embodiment of the present invention, disk units may be brazed or soldered together to form a unitary unit.
In yet another embodiment of the present invention, disk units may be made of aluminum, either with cladding or without cladding. Disk units may also be made of stainless steel, copper or other ferrous or non-ferrous materials. Disk units may also be a plastic material or other composite materials. Disk units may also be made of combination of any or all of the mentioned materials.
In another embodiment of the present invention, disk units may be manufactured by stamping, cold forging, or machining.
In a further embodiment of the present invention, disk units may be brazed together or soldered together to form a unitary unit.
In a further embodiment of the present invention, disk units may be round, oval, or any other geometric shape.
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 accompanied drawings.
The present invention is directed to a disk type heat exchanging apparatus having a heat exchange media directing member within, useful in applications requiring heat exchange from one heat exchange media to another heat exchange media.
The details of embodiments of heat exchange media flow within a chamber is described in US PAT. application referred to above such as Nitta, U.S. patent application Ser. No. 12/148,655, the disclosure of which is hereby incorporated by reference in its entirety.
Referring to the drawings and in particular
Referring to
Referring to
Referring to
There are many embodiments of connecting members, as illustrated in
When plurality of disk units is combined together to form a single unitary unit as illustrated in
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.
This application is a continuation-in-part of U.S. patent application Ser. No. 12/148,655, filed Apr. 21, 2008, now U.S. Pat. No. 7,987,900, and is related to U.S. patent application Ser. No. 12/856,179, filed Aug. 13, 2010, the entire contents of which are incorporated herein by reference.
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Number | Date | Country | |
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Number | Date | Country | |
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Parent | 12148655 | Apr 2008 | US |
Child | 12886559 | US |