Patent Application
20100175862
Not applicable.
1. Field of the Invention
The present invention relates to heat exchangers and methods of making and using such heat exchangers. In another aspect, the present invention relates to aluminum heat exchangers and methods of making and using such heat exchangers. In even another aspect, the present invention relates to aluminum heat exchangers having at least two exchanger cores in a split arrangement with the inlet and outlet piping traversing the split and manifolds communicating flow with each core. In still even another aspect, the present invention relates to aluminum heat exchangers operating in parallel through the use of a manifold arrangement.
2. Brief Description of the Related Art
An aluminum plate-fin heat exchanger (brazed aluminum heat exchanger or aluminum plate heat exchanger) is a type of heat exchanger design that uses plates and finned chambers to transfer heat between fluids. It is often categorized as a compact heat exchanger to emphasize its relatively high heat transfer surface area to volume ratio. The plate-fin heat exchanger is widely used in many industries, including the aerospace industry for its compact size and lightweight properties, as well as in cryogenics where its ability to facilitate heat transfer with small temperature differences is utilized.
Quite commonly, a plate-fin heat exchanger is comprised of layers of corrugated sheets separated by flat metal plates, typically aluminium, to create a series of finned chambers. In some units, separate hot and cold fluid streams flow through alternating layers of the heat exchanger and are enclosed at the edges by sidebars. In some units, heat is transferred from one stream through-the fin interface to the separator plate and through the next set of fins into the adjacent fluid. The fins also serve to increase the structural integrity of the heat exchanger and allow it to withstand high pressures while providing an extended surface area for heat transfer.
There are many patents and applications directed to aluminum plate heat exchangers, including the following.
U.S. Pat. No. 4,368,776, issued Jan. 18, 1983, to Negita et al., discloses an aluminum heat exchanger with excellent corrosion resistance and particularly suited for adaptation as radiator for automobiles, the heat exchanger having a 2- or 3-layer coating film structure consisting of a zinc-diffused layer formed on the surface of an aluminum base and a waterproof organic film formed on the zinc-diffused layer with or without a phosphoric acid-chromate coating there between, whereby the surface of the aluminum base is not directly contacted with at least the water-containing heat exchange medium.
U.S. Pat. No. 4,716,959, issued Jan. 5, 1988 to Aoki, discloses a serpentine-type aluminum heat exchanger comprising a serpentine-anfractuous flat tube of an aluminum alloy and a plurality of corrugated fin units made of an aluminum alloy having a high aluminum content of 99 weight percent or more, and joined to the flat tube by brazing metal coating layers fixed onto flat surfaces of parallel portions of the serpentine-anfractuous flat tube. The heat exchanger is produced by preparing the serpentine-anfractuous flat tube of an aluminum alloy, the corrugated fin units and foil plates of an aluminum alloy brazing filler metal, disposing the fin units in spaces between adjacent ones of parallel portions of the serpentine-anfractuous flat tube with foil plates being interposed between respective fin units and opposite parallel portions of the flat tube, and heating the flat tube, the fin units and foil plates in the assembled relation to the brazing temperature.
U.S. Pat. No. 5,295,302, issued Mar. 22, 1994 to Takai et al., discloses a method of manufacturing an aluminum heat exchanger made from flat aluminum tubes formed with side edge projections having engaging surfaces and coated with brazing material on the outside surface but not on the inside surface of the tube or the projections. The opposite ends of the tubes are inserted into flat tube insertion holes in opposed header tanks which have a brazing material coated on the peripheral surface of the tank, so that, during brazing of the assembled heat exchanger components, brazing material flows from the header tanks to the engaging surfaces of the flat tubes.
U.S. Pat. No. 6,620,274, issued Sep. 16, 2003, to Nagaya et al., discloses a method of repairing an aluminum heat exchanger by closing a hole in the damaged portion with an acrylic resin adhesive material. A certain area around the damaged portion is pressed down to form a cup-shaped depressed portion. The adhesive material is supplied to the depressed portion so that it is retained therein, and then hardened by curing under the room temperature. The hardened adhesive material completely closes the hole with a sufficient thickness and strength because it is retained in the depressed portion. The adhesive material is cured in a relatively short time because the acrylic resin is used as the adhesive material.
U.S. Pat. No. 6,006,430, issued Dec. 28, 1999, to Fukuoka et al., discloses an aluminum heat exchanger that includes laminated aluminum tubes and corrugated fins, a core portion receiving respective ends of tubes into sheet metals members, and iron or stainless steel inserts having high strength receiving U-shaped folded pieces of the sheet metal members contacting the corrugated fins at the outermost portion of the core portion. The tubes and the corrugated fins are held and pressed from both sides of the core portion by the inserts and the corrugated fins are protected from coming apart during a brazing operation.
U.S. Patent Application 20050011636, published Jan. 20, 2005 to Miyachi, discloses an aluminum heat exchanger excellent in corrosion resistance that is assembled by brazing an aluminum fin material to the outer surface of an aluminum tube material formed by bending a sheet material, in particular, an aluminum heat exchanger which can be suitably used as an automotive heat exchanger such as a condenser or evaporator. The tube material is formed of a two-layer clad sheet that includes a core material and an Al—Zn alloy layer clad on the core material. The Al—Zn alloy layer is clad on the outer surface of the tube material and brazed to the aluminum fin material. The potential of the Al—Zn alloy layer in normal corrosive solution is 100 mV or more lower than the potential of the core material in the normal corrosive solution. The potential of the Al—Zn alloy layer in the normal corrosive solution is lower than the potential of the core material in high-concentration corrosive water.
U.S. Patent Application 20050045314, published Mar. 3, 2005 to Elbourini, discloses an aluminum heat exchanger and method of making thereof useful for motorized power systems similar to those utilized in the automotive industry for engine heat exchange, including, in particular, radiators. In a preferred method, the flat tubes of the heat exchanger are formed from flat sheet braze material and at least one portion is formed approximately normal to the wide portion (major axis) and parallel to the minor axis of the tube.
U.S. Pat. No. 6,886,349, issued May 3, 2005, to Curicuta, discloses a brazed aluminum heat exchanger comprising a fin having a first aperture therethrough with a flange formed around the first aperture. The fin is made from a first alloy having a first melting point. The heat exchanger includes a refrigerant tube made from a second alloy having a second melting point. The refrigerant tube extends through the first aperture. The heat exchanger also has a tubular coupling made from a third alloy having a third melting point and that is coupled to an end of the refrigerant tube. A fourth alloy having a fourth melting point less than the first, second, and third melting points is interposed the refrigerant tube and the flange, and further interposed the refrigerant tube and the tubular coupling. A method of manufacturing and a refrigeration unit are also provided.
U.S. Pat. No. 6,964,296, issued Nov. 15, 2005 to Memory et al., discloses that inefficiencies found in round tube plate fin heat exchangers are eliminated in an aluminum heat exchanger that includes first and second headers and at least one flattened tube extending between the headers. A plurality of generally parallel tube runs are defined and each has opposite edges. A plurality of plate fins are arranged in a stack and each has a plurality of open ended slots, one for each run of the tubes. Each of the tube runs is nested within corresponding slots and the fins with one of the edges of the tube runs extending outwardly of the corresponding fin. The assembly is brazed together.
U.S. Pat. No. 7,438,121, issued Oct. 21, 2008, to Minami et al., discloses an aluminum heat exchanger and method for manufacturing the same that includes the steps of: obtaining a heat exchanger tube by forming a Zn thermally sprayed layer on a surface of an aluminum flat tube core so as to adjust Zn adhesion; obtaining a heat exchanger core by alternatively arranging the heat exchanger tube and an aluminum fin and brazing the heat exchanger tube and the fin with end portions of the heat exchanger tube connected to aluminum headers in fluid communication; and forming a chemical conversion treatment coat (corrosion resistance coat) on a surface of the heat exchanger core by subjecting the surface of the heat exchanger core to chemical conversion treatment using at least one chemical conversion treatment agent selected from the group consisting of phosphoric acid chromate, chromic acid chromate, phosphoric acid zirconium series, phosphoric acid titanium series, fluoridation zirconium series, and fluoridation titanium series. The obtained heat exchanger has a long last good corrosion resistance and can prevent occurrence of fin detachment and pit corrosion.
U.S. Patent Application 20080257533, published Oct. 23, 2008 to Rottmann, discloses a method of producing a corrosion resistant aluminum heat exchanger having increased resistance to galvanic corrosion. The exterior of one end of the aluminum tube or connector is coated with a metal or metal alloy. This end is brazed onto a copper or copper alloy inlet or outlet tube. The metal or metal alloy coating inhibits the formation of galvanic corrosion.
U.S. Patent Application No. 20080308263, published Dec. 18, 2008, to Kolb, discloses a heat exchanger manifold sealing system with improved sealing between the tank and header. The manifold includes a plastic heat exchanger tank having an opening for mating with a header and a lip extending substantially around a periphery of the opening. The lip has an outer surface and an upper surface extending outward of the tank opening, and a ridge extending upward from a portion of the upper surface extending substantially around the tank. The manifold further includes an aluminum heat exchanger header adapted to connect to a heat exchanger core. The header has a groove around the periphery thereof receiving the tank lip and a plurality of plastically deformable tabs extending from an edge of the groove. The tabs are bent inward and contact the ridge on the tank lip to secure the tank to the header.
U.S. Patent Application 20090008068, published Jan. 8, 2009 to Minami, discloses a method of manufacturing an aluminum heat exchanger tube. In forming a thermally sprayed layer on a surface of an aluminum flat tube by thermally spraying Al—Si alloy thermal-spraying particles, quenching the thermally sprayed thermal-spraying particles in a molten state to make them adhere to the tube core. The surface of the thermally sprayed layer is smoothed with, e.g., reduction rolls to form a brazing layer. With this method, brazing defects due to fin detachment, erosion to the tube of the brazing material, etc., can be prevented, resulting in good brazing performance.
All of the patents cited in this specification, are herein incorporated by reference.
However, in spite of the above advancements, there still exists a need in the art for aluminum plate heat exchangers.
This and other needs in the art will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.
It is an object of the present invention to provide for aluminum plate heat exchangers.
This and other objects of the present invention will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.
According to one embodiment of the present invention, there is provided an aluminum plate heat exchanger that may include a first core and a second core defining a piping space therebetween. The heat exchanger may also include at least one inlet manifold and at least one outlet manifold, each manifold in fluid communication with the first core and the second core. The heat exchanger may also include inlet piping in fluid communication with the inlet manifold. The heat exchanger may also include outlet piping in fluid communication with the outlet manifold. Additionally, at least a portion of the inlet piping or at least a portion of the outlet piping may be positioned in the piping space.
The following drawings illustrate some of the many possible embodiments of this disclosure in order to provide a basic understanding of this disclosure. These drawings do not provide an extensive overview of all embodiments of this disclosure. These drawings are not intended to identify key or critical elements of the disclosure or to delineate or otherwise limit the scope of the claims. The following drawings merely present some concepts of the disclosure in a general form. Thus, for a detailed understanding of this disclosure, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals.
The present invention will be explained by reference to the drawings.
The present invention will be illustrated mostly by reference to condensing natural gas into LNG using a nitrogen/oxygen refrigerant, although is should be understood that the present invention is not to be so limited and certainly, any suitable fluid may be cooled, and any suitable refrigerant may be utilized.
Heat exchanger 240 is believed to have applicability for cooling natural gas into LNG, especially in the process as disclosed in U.S. Patent Application entitled Methods and Apparatus for Liquefaction of Natural Gas and Products Therefrom, filed on even date herewith, by Susan P. Walther, the application of which is incorporated by reference.
Referring collectively to
Heat exchanger 240 includes at least two core members that will define a piping space 249 between them. The non-limiting embodiment as shown includes four core members 281, 282, 283, and 284, certainly, any desirable number of two or more core members may be utilized. As shown in
Piping space 249 provides room for inlet and outlet piping and through the use of manifolds communicating with the inlet and outlet piping allows for a more space efficient heat exchanger. In some embodiments of the present invention, the manifolds will allow for operating the at least two of the various heat exchanger cores 281-284 in parallel manner with each other.
Piping 110 is the incoming stream for the fluid to be cooled. The natural gas of piping 110 is distributed in parallel fashion across heat exchanger cores 281-284 by manifold 110M. This natural gas of piping 110 is cooled within the cores 281-284 and gathered in manifold 211M and exits heat exchanger 240 through piping 211 as a cryogenic fluid which may be depressured to form LNG.
The remaining piping is related to the refrigerant streams. Certainly, each of the piping may be connected to independent streams that will flow to or from heat exchanger 240. In one non-limiting example, two interconnected refrigeration loops flow through the piping of heat exchanger 240.
In a first loop, piping 220 receives a first steam to be cooled in heat exchanger 240 that is formed into a cooled first steam carried by piping 221. Piping 220 feeds into manifold 220M which distributes the first stream to the various heat exchanger cores 281-284. Away from heat exchanger 240, this cooled first stream is expanded into an expanded first stream and received by piping 222. This expanded first stream is utilized to cool natural gas of piping 110 and exits exchanger 240 in piping 223 as heated first stream. Additionally this expanded first stream may also provide cooling to any other stream in heat exchanger 240 as may be desired.
In a second loop, piping 232 receives a second stream to be cooled in heat exchanger 240 that is formed into a cooled second stream carried by piping 233. This second stream of piping 232 may be at a higher pressure than the first stream of piping 220. Away from heat exchanger 240, this cooled second stream is expanded into an expanded second stream and received by piping 234. This expanded second stream is utilized to cool natural gas of piping 110, and exits heat exchanger 240 through piping 235 as the heated second stream. Additionally this expanded second stream may also provide cooling to any other stream in heat exchanger 240 as may be desired.
In some embodiments of operating heat exchanger 240, the pressure of expanded first stream of piping 222 and of expanded second stream of piping 234 may be at about the same pressure to allow for the combining of heated first stream of piping 223 and of heated first stream of piping 235, to form a combined refrigerant stream. This combined refrigerant stream may be compressed and cooled and then subsequently split into the first stream and second stream as described above and the cycle will continue.
Some embodiments of the present invention allow for positioning of the natural gas streams on one side of the heat exchanger 240, and for positioning of the refrigerant streams on the other side of exchanger 240, for facilitating safety, operational, and/or mechanical layout concerns.
The present disclosure is to be taken as illustrative rather than as limiting the scope or nature of the claims below. Numerous modifications and variations will become apparent to those skilled in the art after studying the disclosure, including use of equivalent functional and/or structural substitutes for elements described herein, use of equivalent functional couplings for couplings described herein, and/or use of equivalent functional actions for actions described herein. Any insubstantial variations are to be considered within the scope of the claims below.
