PANEL HEAT EXCHANGER FORMED FROM PRE-FORMED PANELS

Abstract: A panel (11) for a panel heat exchanger is disclosed, as well as panel heat exchangers formed from preformed panels. The panels (11) have a single layer of a plurality of tubes (14) in a spaced apart side-by-side relationship that are bonded to and provide fluid flow communication with manifolds (12, 13). The panels (11) are adapted to be bonded together in a laminar manner to form panel heat exchangers. Thus, panel heat exchangers are formed from preformed panels, optionally using "off the shelf" panels. A variety of fluid flow configurations may be used. The material of construction is preferably thermoplastic polymer. End uses depend on the polymer of construction, but may include refrigeration and automotive end uses.

Description: PANEL HEAT EXCHANGER FORMED FROM PRE-FORMED PANELS The present invention relates to a panel heat exchanger, and especially to panels for a panel heat exchanger, in which the panels are formed from tubes with manifolds joined thereto. A plurality of such preformed panels is used to form the panel heat exchanger. Preferably, all of the panel is formed from a thermoplastic polymer. Panel heat exchangers formed from thermoplastic polymers and methods for the manufacture of such heat exchangers are known. For instance, a number of heat exchangers formed from thermoplastic polymers and methods for the manufacture thereof are disclosed in PCT patent application O91/02209 of A.J. Cesaroni, published 1991 February 21, and in the published patent applications referred to therein. Tubular heat exchangers are also described by E.L. Fletcher and T.H. Kho in U.S. Patent 4 923 004, issued 1990 May 08. A preferred material of construction is aliphatic polyamide. While panel heat exchangers formed from thermoplastic polymers have been fabricated by the techniques described in the above published documents, improvements in the construction and methods of fabrication would be beneficial to add further flexibility and economy to the fabrication and use of the panel heat exchangers. A panel heat exchanger formed from a preformed panel having tubes and manifolds has now been found. Accordingly, the present invention provides a panel for a panel heat exchanger comprising: a plurality of tubes in a single layer, said tubes being spaced apart in a side-by-side relationship; and a first and a second manifold, each of said manifolds being in the shape of a plate having a continuous peripheral wall and with at least one face of said plate that is planar, at least one of said planar faces on each of said first and second manifold being open and a section of said wall having a plurality of channels therethrough in the plane of the plate; each of said plurality of tubes being bonded at opposing ends thereof to a channel of said first manifold and said second manifold so as to provide fluid flow communication between the open faces of said first and second manifolds through the tubes; said manifolds being capable of being bonded to like manifolds in a face to face manner, said peripheral walls of the manifolds on the face to be bonded being coplanar with the plane of the tubes and said manifolds being open on at least said face being bonded. In a preferred embodiment of the panel of the present invention, the channels are parallel and the tubes are preferably parallel. In another embodiment, the diameters of the tubes are in a plane. In a further embodiment, the tubes are linear. In addition, the present invention provides a panel heat exchanger comprising at least two panels bonded together in a laminar stacked relationship, each panel comprising a plurality of tubes in a single layer and a first and a second manifold, said tubes being spaced apart in a side-by-side relationship and each of said manifolds being in the shape of a plate having a continuous peripheral wall and with at least one face of said plate that is planar, at least one of said planar faces on each of said first and second manifold being open and a section of said wall having a plurality of channels therethrough in the plane of the plate; each of said plurality of tubes being bonded at opposing ends thereof to a channel of said first manifold and said second manifold so as to provide fluid flow communication between the open faces of said first and second manifolds through the tubes; said manifolds of one panel being bonded to the manifolds of a second panel in a face-to-face and fluid-tight manner, said peripheral walls of the manifolds on the face that is bonded being coplanar with the plane of the tubes and said manifolds being open on at least said face being bonded. The present invention relates to panels for panel heat exchangers. The panel heat exchangers are formed from a plurality of such panels by bonding the panels together in a laminar manner. The invention will be described with particular reference to the drawings in which: Fig. 1 is a schematic representation of a plan view of a panel; Fig. 2 and 3 are schematic representations of manifolds of a panel; Fig. 4 and 5 are schematic representations of alternative embodiments of manifolds of a panel; and Fig. 6 is a schematic representation of a plurality of panels in laminar arrangement, forming a panel heat exchanger. Reference is made herein to both first and second manifolds and to inlet and outlet manifolds. In many instances, such expressions are synonymous, an exception being with respect to embodiments of the type illustrated in Fig. 2. Referring to Fig. 1, a panel (generally indicated by 11) is shown as being formed from inlet manifold 12, outlet manifold 13 and a plurality of tubes 14. Tubes 14 are located between inlet manifold 12 and outlet manifold 13, and are in a parallel spaced apart and side-by-side relationship with each other. The plurality of tubes 14 are also in the same plane, as more easily seen in Fig.s 2-6. Each of inlet manifold 12 and outlet manifold 13 is shown as being formed by walls 15 that form the periphery of each manifold, each manifold otherwise being open. Although the embodiment shown has the inlet manifold on one end and the outlet manifold on the other end, the inlet and outlet manifolds may be on the same end, as shown in Fig. 2, with a manifold or chamber for reversal of fluid flow on the other end of the panel i.e. some of the tubes are used for flow in one direction and the remainder are used for flow in the other direction; in this embodiment the panel would have a manifold of Fig. 2 on one end and a manifold of Fig. 3 on the other end. Fig. 2 shows a panel end 21 having a first manifold 22 and a second manifold 23. First manifold 22 is separated from second manifold 23 by barrier 24. Tubes 25 are in fluid flow communication with first manifold 22 through channels 26. Similarly, tubes 27 are in fluid flow communication with second manifold 23 through channels 28. Fig. 3 is similar to Fig. 2, except that there is only one manifold i.e. the barrier 24 in Fig. 2 has been omitted. Fig. 3 shows a panel end 31 having a manifold 32. Tubes 33 are in fluid flow communication with manifold 32 through channels 34. Fig. 4 shows end section 41 that is of similar design to panel end 21 shown in Fig. 2. However, two of end sections 41 in face to face relationship would be required to form panel end 21. Fig. 4 shows an end section 41 having a first manifold 42 and a second manifold 43. First manifold 42 is separated from second manifold 43 by barrier 44. End section 41 has grooves 45 and 46 in a location corresponding to the location of tubes 25 and 27 in Fig. 2. Grooves 45 and 46 are of circular cross-section and of a size to accept tubes 25 and 27. Fig. 5 shows a cross-section of end section 41 along A-A of Fig. 4. End section member 51 is shown as having grooves 52 of substantially semi-circular cross section, but being adapted so as to accept tubes. Fig. 6 shows a panel heat exchanger 61 that has an inlet 62 and an outlet 63. Inlet 62 and outlet 63 are joined together by a plurality of panels 64. Each of panels 64 are of the construction described above, with a plurality of tubes 65 extending from inlet 62 to outlet 63. Outlet 63 is shown as being partially cutaway, to reveal channels 66 of tubes 65. Inlet 62 and outlet 63 are formed by the bonding together in a face-to-face manner of manifolds of the type described above, especially in Fig. 2 and Fig. 3. While the tubes are shown in the drawings aε being both linear and parallel to each other, it is to be understood that this is a preferred embodiment and that other arrangements of tubes in a side-by-side relationship may be used. For example, the tubes may be non-linear i.e. curved or looped or in other convenient configurations. A number of fabrication techniques may be used to fabricate the panels described herein. The tubing is bonded to manifolds at each end of the tubing. The manifold may be characterized by having channels in the wall thereof into which the tubing may be inserted and bonded. Alternatively, end sections of the type shown in Fig. 4 may be used in which event the ends of the tubing are laid in the grooves; a second similar end section is then placed over the tubing to complete the manifold, and heated in a press to effect bonding and formation of the manifold. The design of the manifolds is selected depending on the construction of the heat exchanger and the desired flow pattern through the heat exchanger. For instance, if the flow pattern was to be directly from one end to the other, two manifolds of the type shown in Fig. 3 would be used, one as inlet manifold and one as outlet manifold. Alternatively, a manifold of the type shown in Fig. 2 could be used on one end and a manifold of the type shown in Fig. 3 could be used on the other end; in operation, fluid would flow from inlet manifold 22, through tubes 25 to manifold 32 and return through tubes 27 to outlet manifold 28. In this latter mode of operation, the inlet and outlet manifolds are on the same end of the panel, with the manifold on the opposite end of the panel being merely to reverse the direction of flow through the panel. While the manifolds need to be open on at least one face, it is to be understood that shims could be used to cover the other face of a manifold, thereby altering flow patterns, so as to maintain a desired residence time of the fluid in the panel heat exchanger by restrictions to the path of the fluid. The panel heat exchanger is formed by taking a desired number of panels of the required configurations, optionally including shims, and placing the panels in a face to face relationship so that the manifolds cooperatively will form fluid tight inlets and outlets of the heat exchanger. The manifold sections are then bonded together, used heat and/or adhesives, depending in particular on the polymer used in the fabrication of the panels, especially the manifolds. The inlet and outlet require suitable connectors to permit fluid to enter and pass from the heat exchanger. In operation, fluid would enter the inlet e.g. inlet 62, pass through tubes (65) to outlet 63. The panel heat exchanger would normally have the manifolds of a construction such that fluid passed several times from one side of the panel heat exchanger to the other e.g. in a zig-zag manner, to increase the efficiency and effectiveness of the operation of the panel heat exchanger. In embodiments, the centres of tubes in adjacent stacked panels are not in alignment but are off-set by, for instance, one half of a diameter. Such an off-set nature of the tubes is believed to be beneficial for efficient heat exchange. The sheets may be formed from a variety of polymer compositions. The composition selected will depend primarily on the end use intended for the heat exchanger, especially the temperature of use and the environment of use, including the fluid that will be passed through the heat exchanger and the fluid e.g. air, external to the heat exchanger. In the case of use on a vehicle, the fluid may be air that at times contains salt or other corrosive or abrasive matter, or the fluid may be liquid e.g. radiator fluid. While it is preferred to use the same or similar polymer compositions for both tubing and manifolds, the tubes and manifolds may be fabricated from different polymers, the requirement being that acceptable bonding may be achieved. A preferred polymer of construction is polyamide. Examples of polyamides are the polyamides formed by the condensation polymerization of an aliphatic dicarboxylic acid having 6-12 carbon atoms with an aliphatic primary diamine having 6-12 carbon atoms. Alternatively, the polyamide may be formed by condensation polymerization of an aliphatic lactam or alpha,omega aminocarboxylie acid having 6-12 carbon atoms. In addition, the polyamide may be formed by copolymerization of mixtures of such dicarboxylic acids, diamines, lactams and aminocarboxylic acids. Examples of dicarboxylic acids are 1,6-hexanedioic acid (adipic acid), 1,7-heptanedioic acid (pimelic acid), 1,8-octanedioic acid (suberic acid), 1,9-nonanedioic acid (azelaic acid), 1,10-decanedioic acid (sebacic acid) and 1,12-dodecanedioic acid. Examples of diamines are 1,6-hexamethylene diamine, 2- methyl pentamethylene diamine, 1,8-octamethylene diamine, 1, 10-decamethylene diamine and 1,12-dodecamethylene diamine. An example of a lactam is caprolactam. Examples of alpha,omega aminocarboxylic acids are a ino octanoic acid, amino decanoic acid and amino dodecanoic acid. Preferred examples of the polyamides are polyhexamethylene adipamide and polycaprolactam, which are also known as nylon 66 and nylon 6, respectively. The panels and sheet of the present invention have been described with particular reference to the use of polyamides as the polymer used in the fabrication thereof. It is to be understood, however, that other polymers may be used, the principal consideration being the environment of use of the panel heat exchanger e.g. the properties of the fluid passing through and over the panel heat exchanger, the temperature and pressure of use and the like. Examples of other thermoplastic polymers that may be used are polyethylene, polypropylene, fluorocarbon polymers, polyesters, thermoplastic and thermoset elastomers e.g. polyetherester elastomers, neoprene, ch1orosulphonated polyethylene, and ethylene/propylene/diene (EPDM) elastomers, polyvinyl chloride and polyurethane. It is to be understood that the tubing could be metallic tubing, although plastic tubing is preferred. In preferred embodiments of the present invention, the thickness of tubing used in the fabrication of the panels is less than 0.7 mm, and especially in the range of 0.07-0.50 mm, particularly 0.12-0.30 mm. The polymer compositions used in the fabrication of the panel heat exchangers may contain stabilizers, pigments, fillers, including glass fibres, and the like, as will be appreciated by those skilled in the art. The polymer composition of the tubing and of the manifolds may be the same or different, depending on the intended use of the panel heat exchangers. All seals in the panel heat exchanger need to be fluid tight seals to prevent leakage of fluid from the heat exchanger. The panel heat exchangers and the process of manufacture provide a versatile and relatively simple method of fabricating heat exchangers. Simple moulds and fabrication techniques may be used. Panel heat exchangers may be custom made, using panels that have been preformed and are effectively "off the shelf". Combinations of panels of differing configurations may be used, by suitable selection of the panels, with a myriad of flow patterns being possible. The heat exchangers may be used in a variety of end-uses, depending on the polymer(s) from which the heat exchanger has been fabricated and the intended environment of use of the heat exchanger. In embodiments, the panel heat exchangers may be used in automotive end uses e.g. as part of the water and oil cooling systems. In other embodiments, the panel heat exchangers may be used in marine end-uses, including for craft that will operate on the sea. The panel heat exchangers may also be used in less demanding end uses e.g. in refrigeration and in comfort heat exchangers, including heating of rooms, floors and the like, and domestic uses. The present invention is illustrated by the following examples. Example I As an illustration of the invention, a panel heat exchanger of the type described above with reference to Fig. 6 was fabricated from polyhexamethylene adipamide compositions. The manifolds were of the shape shown in Fig. 2. Each panel consisted of 10 tubes and the inlet and outlet manifolds. The panel heat exchanger had six panels. The tubing had a wall thickness of 0.36 mm and an outer diameter of 4.3 mm, and had been formed by extrusion of a polyhexamethylene adipamide composition. The panels were formed by bonding tubing into channels in the manifolds using an adhesive of the type described in European patent application No. 287 271 of A.J. Cesaroni, published 1988 October 19. Heat was applied to effect bonding. The panel heat exchanger was formed from panels using the same technique. The resultant panel heat exchanger was tested and found to be fluid tight.

Claims: CLAIMS : 1. A panel for a panel heat exchanger comprising: a plurality of tubes in a single layer, said tubes being spaced apart in a side-by-side relationship; and a first and a second manifold, each of said manifolds being in the shape of a plate having a continuous peripheral wall and with at least one face of said plate that is planar, at least one of said planar faces on each of said first and second manifold being open and a section of said wall having a plurality of channels therethrough in the plane of the plate; each of said plurality of tubes being bonded at opposing ends thereof to a channel of said first manifold and said second manifold so as to provide fluid flow communication between the open faces of said first and second manifolds through the tubes; said manifolds being capable of being bonded to like manifolds in a face to face manner, said peripheral walls of the manifolds on the face to be bonded being coplanar with the plane of the tubes and said manifolds being open on at least said face being bonded. 2. The panel of Claim 1 in which the channels are parallel. 3. The panel of Claim 1 or Claim 2 in which the tubes are parallel. 4. The panel of any one of Claims 1-3 In which the diameters of the tubes are in a plane. 5. The panel of any one of Claims 1-4 in which the tubes are linear. 6. The panel of any one of Claims 1-5 in which the tubes and manifolds are fabricated from a thermoplastic polymer. 7. The panel of Claim 6 in which the polymer is a polyamide. 8. A panel heat exchanger comprising at least two panels bonded together in a laminar stacked relationship, each panel comprising a plurality of tubes in a single layer and a first and a second manifold, said tubes being spaced apart in a side-by- side relationship and each of said manifolds being in the shape of a plate having a continuous peripheral wall and with at least one face of said plate that is planar, at least one of said planar faces on each of said first and second manifold being open and a section of said wall having a plurality of channels therethrough in the plane of the plate; each of said plurality of tubes being bonded at opposing ends thereof to a channel of said first manifold and said second manifold so as to provide fluid flow communication between the open faces of said first and second manifolds through the tubes; said manifolds of one panel being bonded to the manifolds of a second panel in a face-to-face and fluid-tight manner, said peripheral walls of the manifolds on the face that is bonded being coplanar with the plane of the tubes and said manifolds being open on at least said face being bonded. 9. The panel heat exchanger of Claim 8 in which the tubes and manifolds are fabricated from a thermoplastic polymer. 10. The panel heat exchanger of Claim 9 in which the polymer is a polyamide.

Inventors: CESARONI ANTHONY JOSEPH, CESARONI, ANTHONY, JOSEPH
Applicants: CESARONI ANTHONY JOSEPH, CESARONI, ANTHONY, JOSEPH
Application year: 1993
Main classification: F28F21
IPC codes: F28F9, F28F21