Abstract:
The present invention provides a heat exchange apparatus used as a cooling apparatus for hydraulic oil that operates a hydraulic machine. A heat exchange apparatus includes multiple embedded tubes through which a heat medium passes, are installed in the interior of a shell having thermal fluid, such as hydraulic oil, passing therethrough to allow a heat exchange between the heat medium and the thermal fluid. The shell of the heat exchange apparatus includes coupling the multiple tubes to closure thin plates that are a metal plate cut or bent in a predetermined shape, combining the closure thin plates in a box form, and forming a synthetic resin coating layer on the exterior surfaces of the closure thin plates. Thus, the heat exchange apparatus achieves productivity improvements and manufacturing cost reductions while ensuring performance including pressure resistance and air tightness, and durability.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation application of International Application No. PCT/KR2014/010422 filed on Nov. 3, 2014, which claims priority to Korean Application No. 10-2013-0146092 filed on Nov. 28, 2013. The applications are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a heat exchange apparatus used as an apparatus for cooling down hydraulic oil for operating a hydraulic machine or the like and, more specifically, to a heat exchange apparatus having a plurality of tubes  20  embedded therein. The plurality of tubes  20  through which a heat medium such as a coolant passes is installed within a shell  10  through which a thermal fluid such as the hydraulic oil passes to provide heat exchange between the heat medium and the thermal fluid. The shell  10  of the heat exchange apparatus is formed by coupling the plurality of tubes  20  to closure thin plates  12 , i.e., metal plates cut or bent in a predetermined shape, assembling the closure thin plates  12  in the form of a box, and forming a synthetic resin coating layer  11  on the exterior surface of the closure thin plates  12 . 
       BACKGROUND ART 
       [0003]    Generally, a heat exchange apparatus for a fluid, a method of installing a plurality of tubes  20  within the interior of a shell  10  to perform heat exchange between a fluid passing through the shell  10  and a fluid passing through the tubes  20  is widely used, and Korean Patent 48150552v.1 Registration No. 1151755 is an example of the method. [Please include in Information Disclosure Statement.} 
         [0004]    In particular, the Korean Patent Registration No. 1151755 relates to a heat exchange apparatus for cooling down hydraulic oil for operating a hydraulic machine, in which the hydraulic oil corresponds to the fluid passing through the shell  10 , i.e., a thermal fluid, and a coolant corresponds to the fluid passing through the tubes  20 , i.e., a heat medium. 
         [0005]    In other words, as shown in  FIGS. 2A and 2B , the thermal fluid, which is high temperature hydraulic oil flowing into the shell  10 , is discharged after being cooled down while passing through the plurality of tubes  20  installed within the interior of the shell  10  by a heat exchange with the coolant flowing into the bonnet  30  through the feed-and-discharge apertures  33  and passes through the tubes  20 . In the conventional heat exchange apparatus configured as described above, the shell  10  embedded with the tubes  20  is generally configured of a metal enclosure or a thick plate which requires a cutting process after being molded through a casting. 
         [0006]    Typically, in a heat exchange apparatus, for cooling down operating oil of a hydraulic machine, the shell  10  is manufactured using a thick metal plate as shown in  FIG. 1 . Since the shell  10  is a pressure container through which a high pressure fluid such as operating oil of a hydraulic machine directly passes it requires sufficient pressure resistance and strength to endure the pressure of the high pressure fluid. Further, in addition to requiring a high degree airtightness, and based on the cross-sectional view shown in the upper portion of the figure, windings of a complicated shape should be formed within the shell to secure contactness between the thermal fluid passing through the shell  10  and the tubes embedded in the shell  10 . Moreover, at the substantially the same time, the interior surface of the shell  10  should be smoothly processed to minimize the friction between the thermal fluid and the interior wall of the shell  10  and prevent separation of the tissues of the interior wall of the shell  10  which may occur when the heat exchange apparatus is used for an extended period of time. 
         [0007]    The shell  10  of the conventional heat exchange apparatus is completed by cutting or grinding a thick plate primarily molded through a casting. Accordingly, coupling the tubes  20  and welding the thick plates when the thick plates are assembled in the form of a box create a complicated manufacturing process and increase manufacturing cost. In particular, the casting, cutting and grinding processes should be sequentially performed for the formation and surface process of the windings within the shell  10 . Additionally, during the assembly process performed thereafter, a precise thick plate welding process should be performed for connection parts. Since, these processes are difficult to automate and require highly skilled manpower, there is a limit in mass-production of the shell  10  of the conventional heat exchange apparatus, and improvement of productivity and reduction of manufacturing cost through the mass-production are limited. 
         [0008]    In addition, since the exterior surface of the shell  10  of the conventional heat exchange apparatus is formed of metal, the exterior surface of the shell  10  in direct contact with the heat medium including a coolant or the like is corroded. For example, deficiency in corrosion resistance of the shell  10  generates a problem in a heat exchange apparatus of an atomic power plant, a vessel or the like which uses sea water as a heat medium. 
         [0009]    The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
       SUMMARY 
       [0010]    The present invention provides improve productivity and reduces manufacturing cost while securing pressure resistance and preciseness of the interior surface in a shell  10  of a heat exchange apparatus. 
         [0011]    A heat exchange apparatus may include a plurality of tubes  20  disposed within a shell  10 , through which a thermal fluid passes, in a direction perpendicular to the flow of the thermal fluid. A plurality of disk-shaped transfer fins  21  may be formed on the exterior surface of the tubes. Bonnets  30  having compartments  32  formed therein to accommodate a heat medium may be coupled to the shell  10  to connect the tubes  20  and the compartments  32  of the bonnets  30 . A plurality of closure thin plates  12  may be assembled in the form of a box, and the plurality of tubes  20  may be disposed within the interior of the assembled closure thin plates  12  to couple the closure thin plates  12  having a plurality of perforated coupling apertures  13  to both ends of the tubes  20  to expose both end portions of the tubes  20  to the exterior of the closure thin plates  12 . The exterior wall of the shell  10  may be formed from a synthetic resin coating layer  11  on the exterior surface of the closure thin plates  12 . 
         [0012]    According to another aspect of the present invention, a method of manufacturing the heat exchange apparatus described above may include configuring a closure thin plate  12  assembly of a box shape, in which both ends of a plurality of tubes  20  are exposed on both sides of the assembly, by assembling closure thin plates  12  to surround the tubes  20  arranged in parallel in a method of coupling closure thin plates  12  having a plurality of perforated coupling apertures  13  to both ends of the tubes  20  and coupling closure thin plates  12  having an entry-and-exit aperture  19  to both ends of the enclosure thin plate  12  assembly embedded with the tubes  20 . The method may further include setting the closure thin plate  12  assembly of a box shape in a metallic mold  40  in which a mold having a shape of a shell  10  to be manufactured may be formed, in which coupling recess portions  45  having an interior diameter that correspond to the diameter of the tubes  20  are formed on the surfaces, among the interior surfaces of the metallic mold  40 , parallel to both side surfaces of the closure thin plate  12  assembly of a box shape on which the tubes  20  are exposed. When the metallic molds  40  are combined, both ends of the exposed tubes  20  may be coupled to the coupling recess portions  45  of the interior surfaces of the metallic mold  40  to maintain a separated state between the surfaces of the closure thin plate  12  assembly set in the metallic mold  40  and the interior surfaces of the metallic mold  40 . A coating layer  11  may be formed by injecting synthetic resin within the combined metallic mold  40 , and the metallic mold  40  may be separated and removed from the shell  10  when the coating layer  11  is cured. 
         [0013]    Through the present invention, productivity may be improved and manufacturing costs may be reduced while securing performance such as pressure resistance, airtightness and the like and durability of a heat exchange apparatus. Particularly, in configuring the shell  10  of the heat exchange apparatus, since it is possible to omit high-cost and low-productivity processes such as casting, cutting and grinding, which are essential when the shell  10  is manufactured in a conventional technique. For example, the manufacturing process and the productivity may be be drastically improved compared with the conventional technique by molding the shell  10  in multiple layers of the closure thin plate  12  formed within the interior of the shell and the synthetic resin coating layer  11  formed exterior the shell and applying the closure thin plate  12  which may easily automate and mass-produce through a press working or the like. 
         [0014]    Additionally, when the welding is excluded or minimized in the process of manufacturing the shell  10 , excessive heat transfer which may occur in welding a thick plate in the process of manufacturing the shell  10  that uses a conventional technique and defects such as deformation of the tubes  20  caused by the excessive heat transfer may be prevented. When the surface of the shell  100  directly contacting with a thermal medium such as a coolant or the like is formed of synthetic resin, further superior corrosion resistance may be secured compared with a conventional heat exchange apparatus. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The above and other features of the present invention will now be described in detail with reference to exemplary embodiments thereof illustrated the accompanying drawings which are given hereinbelow by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0016]      FIGS. 1A and 1B  are exemplary view showing a conventional heat exchange apparatus of the related art; 
           [0017]      FIGS. 2A and 2B  is an exemplary perspective view and a representative cross sectional view showing a heat exchange apparatus of the present invention; 
           [0018]      FIG. 3  is an exemplary exploded perspective view showing a heat exchange apparatus according to an exemplary embodiment of the present invention; 
           [0019]      FIG. 4  is a partially cut perspective view showing a shell according to an exemplary embodiment of the present invention; 
           [0020]      FIG. 5  is a partially cut perspective view showing a coating layer of a shell according to an exemplary embodiment of the present invention; 
           [0021]      FIG. 6  is an exemplary view showing an assembly method of closure thin plates according to an exemplary embodiment of the present invention; 
           [0022]      FIG. 7  is a perspective view showing an assembly state of closure thin plates according to an exemplary embodiment of the present invention; 
           [0023]      FIG. 8  is an exemplary view showing a metallic mold applied to an exemplary embodiment of the present invention; 
           [0024]      FIGS. 9A and 9B  are views illustrating a combined state of a metallic mold applied to an exemplary embodiment of the present invention; and 
           [0025]      FIGS. 10A and 10B  are partially cut perspective view showing an extracted shell of an exemplary embodiment of the present invention to which a reinforcing bar is applied. 
       
    
    
       [0026]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various exemplary features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
       DETAILED DESCRIPTION 
       [0027]    Hereinafter reference will now be made in detail to various exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other exemplary embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0028]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. For example, in order to make the description of the present invention clear, unrelated parts are not shown and, the thicknesses of layers and regions are exaggerated for clarity. Further, when it is stated that a layer is “on” another layer or substrate, the layer may be directly on another layer or substrate or a third layer may be disposed therebetween. 
         [0029]    It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0030]    It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicle in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats, ships, aircraft, and the like and includes hybrid vehicles, electric vehicles, combustion, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum). 
         [0031]    The detailed configuration and process of the present invention will be hereafter described in detail with reference to the accompanying drawings. 
         [0032]    First,  FIGS. 2A and 2B  are show a perspective view and a representative cross sectional view showing the appearance of the heat exchange apparatus of the present invention. As shown in the figure, the heat exchange apparatus of the present invention may include a structure with a pair of bonnets  30  coupled to a shell  10 , that may be a tightly sealed rectangular enclosure having an entry-and-exit aperture  19  on both of the front and rear sides, and a pair of feed-and-discharge apertures  33  formed on the bonnet  30  of one side as shown in  FIG. 3 . A plurality of tubes  20  having transfer fins  21  formed thereon may be disposed within the interior of the shell  10  as shown in  FIG. 4 . 
         [0033]    In other words, as shown in  FIGS. 2 to 4 , the present invention relates to a heat exchange apparatus, in which a plurality of tubes  20  with a plurality of disk-shaped transfer fins  21  formed on the exterior surface of the tubes may be installed within a shell  10 , through which a thermal fluid passes, in a direction perpendicular to the flow of the thermal fluid. Further bonnets  30  may include compartments  32  formed therein and partitioned by a partitioning wall  31  to accommodate a heat medium and may be coupled to the shell  10  to connect the tubes  20  and the compartments  32  of the bonnets  30 . As shown in  FIG. 4 , the heat exchange apparatus may include a curved surface that repeats a plurality of valleys and peaks formed on the interior surface of the shell  10  to secure the contact efficiency between the thermal fluid and the tubes  20 . 
         [0034]    In the heat exchange apparatus, since the shell  10  provides a pressure container through which high pressure thermal fluid passes, the pressure resistance, as well as high degree airtightness should be included. Further, the present invention, as shown in  FIGS. 4 and 5 , the shell  10  may be formed by coating the exterior of the metal closure thin plates  12  with a synthetic resin coating layer  11 . In other words, the shell  100  of a multiple layer structure may be formed by stacking the synthetic resin coating layer  11  on the exterior surface of the closure thin plates  12  embedded with the tubes  20  and assembled in the form of a box. 
         [0035]    The closure thin plate  12  of the present invention may include a metal plate that forms the interior wall of the shell  10  and may be primarily coupled with the tubes  20 . A plurality of unit closure thin plates  12  may be assembled in the form of a box as shown in  FIG. 6 . In the exemplary embodiment shown, a curved surface repeating valleys and peaks may be formed on the top and bottom closure thin plates  12 , and coupling apertures  13  of the same number and the same positions to correlate with those of the tubes  20  may be perforated on the closure thin plates  12  of both sides, and the entry-and-exit aperture  19  may be formed on the closure thin plates  12  of the front and rear sides. 
         [0036]    Additionally, connection parts between the closure thin plates  12  may be bent and cut in an identical form. For example, when the closure thin plates  12  are assembled in the form of a box, the connection parts may be tightly coupled, and the interior of the assembled closure thin plates  12  may be tightly sealed. 
         [0037]    In other words, as shown in  FIGS. 6 and 7 , a curved surface may be formed on the top and bottom sides of the closure thin plate  12  assembly. Further, the top and bottom portions of the closure thin plates  12  may include a plurality of perforated coupling apertures  13  and may be tightly coupled to both side ends of the top and bottom side closure thin plates  12  in a shape the same as the windings of the curved surface of the top and bottom side closure thin plates  12 . Thus when the closure thin plates  12  are assembled, the connection parts are tightly coupled, and the interior of the assembled closure thin plates  12  may be tightly sealed. 
         [0038]    The closure thin plates  12  of the present invention are assembled in the form of a box while the tubes  20  are embedded therein. In other words both ends of the tubes  20  may be coupled to the coupling apertures  13  formed on the closure thin plates  12  of both sides in the assembly process. Thus both ends of the tubes  20  may be exposed on both sides of the closure thin plate  12  assembly as shown in  FIG. 7 . 
         [0039]    Additionally, as shown in  FIG. 6 , coupling steps  14  protruded toward the interior may be formed along the exterior periphery of the closure thin plates  12  of the front and rear sides. The closure thin plates formed with the coupling step  14  may be coupled to the front and rear sides of the assembly formed by assembling the closure thin plates  12  of both sides and the top and bottom sides as shown in  FIG. 7 . Thus the closure thin plates  12  may be firmly combined in the form of a box without a separate process such as adhering, welding or the like. As described above, the closure thin plates  12  of the present invention may be manufactured by processing a metal plate. In particular, the process of forming the curved surface, cutting the exterior periphery and perforating the coupling apertures  13  may be performed when a press working is applied. For example, through the press working applied to the closure thin plates  12 , the present invention may secure productivity remarkably improved compared with the conventional technique which requires a series of complicated processes that include casting, cutting, grinding and the like. 
         [0040]    As described above, airtightness and pressure resistance may be provided to the shell  10  by stacking the synthetic resin coating layer  11  on the exterior surface of the closure thin plate  12  assembly embedded with the tubes  20  and assembled in the form of a box as shown in  FIG. 5 . For example, this may be accomplished through an injection molding method using a combination type metallic mold  40  as shown in  FIGS. 8 and 9A and 9B . 
         [0041]    A method of manufacturing a heat exchange apparatus of the present invention includes configuring a closure thin plate  12  assembly of a box shape, in which both ends of a plurality of tubes  20  may be exposed on both sides of the assembly as shown in  FIG. 7 . For example, the closure thin plates  12  may be assembled to surround the tubes  20  arranged in parallel in a method of coupling closure thin plates  12  having a plurality of perforated coupling apertures  13  to both ends of the tubes  20  and coupling closure thin plates  12  having an entry-and-exit aperture  19  to both ends of the enclosure thin plate  12  assembly embedded with the tubes  20 . 
         [0042]    Then, as shown in  FIG. 8 , the closure thin plate  12  assembly of a box shape in the metallic mold  40  in which a mold having a shape of a shell  10  to be manufactured may be formed. As, shown in the extracted expansion portion of the figure, coupling recess portions  45  may have an interior diameter that corresponds to the diameter of the tubes  20  formed on the surfaces, among the interior surfaces of the metallic mold  40 , parallel to both side surfaces of the closure thin plate  12  assembly of a box shape on which the tubes  20  are exposed. When the metallic molds  40  are combined, both ends of the exposed tubes  20  may be coupled to the coupling recess portions  45  of the interior surfaces of the metallic mold  40  to maintain a separated state between the surfaces of the closure thin plate  12  assembly set in the metallic mold  40  and the interior surfaces of the metallic mold  40 . 
         [0043]    In order to simultaneously form the synthetic resin coating layer  11  on the entire exterior surface, i.e., six sides, of the closure thin plate  12  assembly of a box shape, a state of separating the closure thin plate  12  assembly from the interior wall of the metallic mold  40  may be be maintained in the metallic mold  40 . Accordingly, a spacer that supports the closure thin plate  12  assembly, that may be an inserted object, within the metallic mold  40  should be installed to maintain the separated state. The spacer may degrade performance such as strength, airtightness, pressure resistance and the like, as well as the exterior appearance of a completed mold product. 
         [0044]    Therefore, in the present invention, the spacer may be excluded, and the coupling recess portions  45  having an interior diameter the same as the diameter of the tube  20  are formed on the both interior surfaces of the metallic mold  40  to have the same number and the same positions as those of the tubes  20  exposed on both sides of the closure thin plate  12  assembly. Thus when the metallic molds  40  are combined, both ends of the exposed tubes  20  may be coupled to the coupling recess portions  45  of the interior surfaces of the metallic mold  40  to maintain a separated state between the surfaces of the closure thin plate  12  assembly set in the metallic mold  40  and the interior surfaces of the metallic mold  40  as shown in  FIGS. 9A and 9B . 
         [0045]    In other words, as shown the cross-sectional view shown in the upper portion of  FIG. 9A , flow of melt synthetic resin injected within the interior of the metallic mold  40  into the tubes  20  may be prevented by accurately and stably maintaining the position of the closure thin plate  12  assembly disposed within the metallic mold  40  when the molding is processed and tightly close the openings on both ends of the tubes  20 . 
         [0046]    As described above, the shell  10  of a multi-layer structure may be completed by performing the step of forming the coating layer  11  by injecting synthetic resin within the interior of the combined metallic mold  40  when the closure thin plate  12  assembly is stably set within the interior of the metallic mold  40 . The metallic mold  40  may be separated and removed from the shell  10  when the coating layer  11  is cured. Thereafter, as shown in  FIG. 3 , a heat exchange apparatus to which the present invention is applied may be completed by attaching the bonnets  30  on both sides of the shell  10 . 
         [0047]    Moreover as shown in  FIGS. 10A and 10B   FIG. 10  views showing an embodiment of coupling a reinforcing bar  47  to the closure thin plate  12  assembly of the present invention. The exemplary embodiment, illustrates that bonding strength of the closure thin plate  12  assembly may be secured, and in addition, pressure resistance of the completed shell  10  may be improved when the reinforcing bar  47  is inserted in the assembly and the metallic mold  40 . 
         [0048]    The invention has been described in detail with reference to exemplary embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these exemplary embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.