Abstract:
The invention relates to a plate heat exchanger ( 1 ) including a first and second end plate ( 2, 3 ), and a core of heat exchanger plates ( 4 ) arranged between the first and second end plate ( 2, 3 ), whereby a plurality of threaded tightening bolts ( 5   a,    5   b,    5   c ) extend between the first and second end plate ( 2, 3 ) and are arranged, with the aid of nuts ( 6 ) or the like, to hold these plates at a desired distance from each other in order to hold the core of heat exchanger plates together, wherein at least one guiding element ( 7, 7   a,    7   b ) for guiding the first end plate ( 2 ) and the heat exchanger plates ( 4 ) relatively the second end plate ( 3 ) is releasably arranged on at least one of the threaded tightening bolts ( 5   a,    5   b ), which guiding element ( 7   a ) extends through an aperture ( 8 ) in the first end plate ( 2 ), where the at least one guiding element ( 7   a,    7   b ) is provided with a through-hole ( 9 ) to receive the at least one of the threaded tightening bolts ( 5   a,    5   b ) and an external geometry ( 10 ) corresponding to a cut-out ( 11 ) of the heat exchanger plates ( 4 ) and the first end plate ( 2 ).

Description:
AREA OF INVENTION 
       [0001]    The present invention refers generally to plate heat exchangers allowing a heat transfer between two fluids at different temperature for various purposes. Specifically, the invention relates to a plate heat exchanger comprising a first end plate, a second end plate and a package of heat exchanger plates placed between the frame plate and the pressure plate. A plurality of threaded tightening bolts extend between the first end plate and the second end plate and are arranged to hold with the aid of nuts or the like these plates at a desired distance from each other in order to hold the package of heat exchanger plates together. 
       BACKGROUND OF INVENTION 
       [0002]    Plate heat exchangers are normally provided with a frame plate, a pressure plate, also called end plates, and a package of heat exchanger plates disposed adjacent to one another and placed between the frame plate and the pressure plate. Gaskets are disposed between the heat exchanger plates. The gaskets are accommodated in gasket grooves on the heat exchanger plate, which are formed during the form-pressing of the heat exchanger plates. Plate heat exchangers further comprise inlet and outlet ports, which extend through the plate package, for handling two or more media in the plate heat exchanger. A plurality of threaded tightening bolts extend between the frame plate and the pressure plate and are arranged to hold with the aid of nuts or the like these plates at a desired distance from each other in order to hold the package of heat exchanger plates together and to ensure that the plate heat exchanger does not leak. 
         [0003]    Heat exchanger plates are normally made by form-pressing of sheet metal and are disposed in the plate package in such a way as to form first plate intermediate spaces, which communicate with the first inlet port and the first outlet port, and second plate intermediate spaces which communicate with the second inlet port and the second outlet port. The first and second plate intermediate spaces are disposed alternately in the plate package. 
         [0004]    The design of heat exchanger plate for plate heat exchangers aims to use as much as possible of heat transfer or heat exchange area for the heat exchange between two or more media, but it also needs take in account how the gaskets can be applied on the heat exchanger plate to be securely fastened and to fulfil its seal functionality. The location of the threaded tightening bolts are preferably selected to achieve a plate heat exchanger not exposed too much stresses. 
         [0005]    SE-C-171 499 shows a plate heat exchanger with a frame plate, a pressure plate, a package of heat exchanger plates, two tie bars as well as a special supporting device. The frame plate and the supporting device are both provided with feet. Through influence from among other things the yokes a pressure is created on the pressure plate and the package of plates is kept together. The construction shows the disadvantage that both the supporting device and the pressure plate with necessity are created in the form of a very strong construction. Further on the auxiliary carrying bar to support plates in connection with mounting and demounting of the heat exchanger constitutes an unnecessary complication. 
         [0006]    In EP-B1-1 027 571 is shown another plate heat exchanger, where tightening bolts have been integrated into the carrying bar and the guide bar, and creates a guiding element for the pressure plate and the heat exchanger plates. The localization of the tightening bolts is thereby more optimal to resist the forces laid onto the plate heat exchanger during operation. The guiding element is surrounded by a protecting sleeve extending from the frame plate to the pressure plate and protecting the threads of the guiding element from engagement with the heat exchanger plates. The guiding element is also arranged to be connected to a supporting device situated at a substantial distance from the pressure plate. 
         [0007]    The drawbacks with the above solutions are that the stresses are and forces are too great if the solutions are applied on larger plate heat exchangers. 
       DISCLOSURE OF INVENTION 
       [0008]    The object of the present invention is to create a construction which is gives an optimal load distribution over the plate heat exchanger still being cheaper and less complicated to manufacture than the one described above. 
         [0009]    The advantages are attained by using at least one guiding element for guiding the first end plate and the heat exchanger plates relatively the second end plate, and where the guiding element is releasably arranged on at least one of the threaded tightening bolts. The guiding element extends through an aperture and the at least one guiding element is provided with a through-hole to receive the at least one of the threaded tightening bolts and an external geometry corresponding to a cut-out of the heat exchanger plates and the first end plate. 
         [0010]    According to another aspect of the invention the plate heat exchanger is provided with two guiding elements, a first guiding element arranged in an upper portion of the plate heat exchanger and a second guiding element arranged in a lower portion of the plate heat exchanger. The first and second guiding element can have an identical cross section profile. 
         [0011]    According to yet another aspect of the invention the second guiding element further is provided with a guiding rail for movably receiving the second guiding element. 
         [0012]    According to still another aspect of the invention the guiding rail for movably receiving the second guiding element is fully or partially supported by the ground. 
         [0013]    According to a further another aspect of the invention the at least one guiding element includes two separate parts, and the at least one guiding element and the guiding rail is made of an extrudable material. 
         [0014]    According to a further another aspect of the invention a supporting device is releasably arranged at a considerable distance from the first end plate at the end of the upper and lower tightening bolts, and extending between the upper and lower tightening bolts. 
         [0015]    According to still another aspect of the invention the at least one guiding element is movable along the tightening bolts and where one part of the guiding element can be removed as the heat exchanger plates are pressed together by the first end plate to form the operating plate heat exchanger, where after the removed one part of the guiding element can be arranged on a free portion of the tightening bolt outside the plate heat exchanger. 
         [0016]    According to another aspect of the invention the object is attained by a plate heat exchanger where the heat exchanger plates rest on the at least one guiding element and where the first end plate rests on a guiding rail, upon which guiding rail the at least one guiding element is movably received. 
         [0017]    Further aspects of the invention are defined in the dependent claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The present invention is now to be explained more closely by means of a description of various embodiments and with reference to the drawings attached hereto. 
           [0019]      FIG. 1  discloses a perspective view of a plate heat exchanger according to an embodiment of the invention; 
           [0020]      FIG. 2  shows a side view of a plate heat exchanger according to an embodiment of the invention; 
           [0021]      FIG. 3  discloses a partial view of a plate heat exchanger according to an embodiment of the invention; 
           [0022]      FIG. 4  discloses a cross section view A-A of a plate heat exchanger according to an embodiment of the invention; 
           [0023]      FIG. 5  discloses a first partial detailed view B of the plate heat exchanger of  FIG. 4  according to an embodiment of the invention; 
           [0024]      FIG. 6  discloses a second partial detailed view C of the plate heat exchanger of  FIG. 4  according to an embodiment of the invention; 
           [0025]      FIGS. 7   a - b  show different views of a guiding element according to the invention; and 
           [0026]      FIGS. 8   a - b  show different views of a guiding rail according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0027]    Heat exchangers are used for transferring heat between two fluids separated by a solid body. Heat exchangers can be of several types, the most common are spiral heat exchangers, tubular heat exchangers and plate heat exchangers. Plate heat exchangers are used for transferring heat between a hot and a cold fluid that are flowing in alternate flow passages formed between a set of heat exchanger plates. The arrangement of heat exchanger plates defined above is enclosed between end plates that are relatively thicker than the heat exchanger plates. The inner surface of each end plate faces the heat transfer plates. 
         [0028]      FIGS. 1-2  disclose a schematic view of a plate heat exchanger  1  comprising a number of compression-molded heat exchanger plates  4 , which heat exchanger plates  4  are provided in parallel to each other and successively in such a way that they form a plate package. The plate package is provided between a first end plate  2 , also called pressure plate, and a second end plate  3 , also called frame plate. Between the heat exchanger plates  4 , first plate interspaces and second plate interspaces are formed. The end plates  2  and  3  are pressed against the plate package and against one another by tightening bolts or tie bars  5   a - c , which extend through the end plates  2  and  3 , and which tightening bolts  5   a - c  are kept in place by nuts  6 ,  20 . 
         [0029]    The plate heat exchanger  1  comprises a first inlet port and a first outlet port for a first medium, and a second inlet port and a second outlet port for a second medium. The inlet and outlet ports extend through the second end plate  3  and the plate package. It is of course also possible for the inlet and outlet ports to be disposed on both sides of the plate heat exchanger  1 , i.e. on both end plates  2  and  3 . The two medium may be led in the same or in opposite directions relative to one another. 
         [0030]    The heat exchanger plates  4  in the shown embodiment are disposed in such a way in the plate package as to form first plate intermediate spaces which communicate with the first inlet port and the first outlet port, and second plate intermediate spaces, which communicate with the second inlet port and the second outlet port. The first and second plate intermediate spaces are disposed alternately in the plate package. The separation of the plate intermediate spaces may be by gaskets extending in gasket grooves formed during the form-pressing of the heat exchanger plates. The gaskets are usually made of a rubber or polymer material. The heat exchanger plates  4  are provided with a corrugated pattern to improve the heat exchange between the two fluids. 
         [0031]    To guide the heat exchanger plates  4 , to protect the threaded tightening bolts  5   a ,  5   b  from wear of the heat exchanger plates  4 , to simplify the construction and to make the construction cheaper, there has been provided guiding elements  7 ,  7   a ,  7   b  on the uppermost and lowermost of the tightening bolts  5   a ,  5   b.    
         [0032]    Compared with state of the art plate heat exchanger the uppermost and lowermost of the tightening bolts  5   a ,  5   b  replace the traditional carrying and guiding bar, which otherwise serve to enable the opening/closing of the plate heat exchanger by enabling the first end plate  2  and the heat exchanger plates  4  to be moved along the carrying bar and the guiding bar while the plate heat exchanger is standing. By providing upper and lower guiding elements  7   a ,  7   b  that arranged on the tightening bolts  5   a - 5   b , respectively, and where the guiding elements  7   a ,  7   b  has an outer cross section geometry (see  FIGS. 7   a - b ) similar to the traditional carrying bar the heat exchanger plates  4 , having a cut-out profile  11  corresponding to an lower portion of the guiding element  7   a ,  7   b  having an external geometry  10 , can be guided along the upper guiding element  7   a . The tightening bolts  5   a ,  5   b  are received in an aperture or through hole  9  of the guiding element  7   a ,  7   b , which through hole  9  extends along the entire longitudinal length of the guiding element  7   a ,  7   b . The guiding element  7   a ,  7   b  is made of an extrudable material to make cheaper to manufacture and to lighten the construction. The extrudable material can be plastic, aluminum or any other suitable construction material. 
         [0033]    Further tightening bolts  5   c  are present in a usual way between the second end plate  3  and the first end plate  2 , and are placed in notches or recesses at the edges of the second end plate  3  and the first end plate  2 . 
         [0034]    Since the guiding element  7   a ,  7   b  is made of an extrudable material it cannot withstand the same load as a corresponding metal construction. Therefore the load of the heat exchanger plates  4  and the first end plate  2  will be transferred to the ground via a second or lower guiding element  7   b  and a guiding rail  12 . The upper guiding element  7   a  and the lower guiding element  7   b  are preferably identical to reduce manufacturing costs, but different shapes are also possible. In the shown embodiment, see e.g.  FIG. 6 , the lower external geometry  10  of the guiding element  7   b  corresponds to an internal shape  16  of the guiding rail  12  enabling the guiding element  7   b  to be secured to the guiding rail  12  and to be movable along the guiding rail  12 . In some applications the plate heat exchanger  1  is arranged on frame, which fully or partially supports the guiding rail  12 . 
         [0035]    The upper guiding element  7   a  extends through an aperture  8  of uppermost portion of the first end plate  2  so that the first end plate  2  can be movable relative to the upper guiding element  7   a . Similarly extends the lower guiding element  7   b  through an aperture  17  of the lowermost portion of the first end plate  2 . Both the lower guiding element  7   b  and the upper guiding element  7   a  only guides the first end plate  2 , whereas the load of the first end plate  2  is carried by the guiding rail  12  upon which the first end plate  2  rests. The heat exchanger plates  4  rest on the lower guiding element  7   b  and is guided laterally by the upper guiding element  7   a.    
         [0036]    Each guiding element  7   a ,  7   b  comprise two parts  13   a ,  13   b ;  14   a ,  14   b  (see  FIG. 3 ) to enable the guiding of the heat exchanger plates  4  during the opening and closing process of the plate heat exchanger  1  and thus enabling an outer guiding element part  14   a ,  14   b  to be removed when the heat exchanger plates  4  and the first end plate  2  are tighten together to form the operational plate heat exchanger  1 , and applying nuts  6  onto the tightening bolt  5   a ,  5   b  to keep the first end plate  2  in place and the heat exchanger plates  4  tighten together between the first end plate  2  and the second end plate  3 . The length of the inner guiding element part  13   a ,  13   b  is preferably slightly less than the length corresponding to the total thickness of all the heat exchanger plates  4  in the package of plates and the first end plate  2 . The length of the outer guiding element part  14   a ,  14   b  is preferably slightly less than the remaining free end of the tightening bolt  5   a ,  5   b  when the inner guiding element part  13   a ,  13   b  has been arranged onto the tightening bolt  5   a ,  5   b.    
         [0037]    The upper guiding element  7   a  can be provided with wear protection arrangement to reduce the wear from the heat exchanger plates  4 . The wear protection arrangement can be of a plate or rubber material or any other suitable material, and is preferably clamped onto the upper guiding element  7   a.    
         [0038]    The guiding element  7   a ,  7   b  has an upper portion formed as an external geometry  19  having a width corresponding to the opening width of the cut-out  11  of the heat exchanger plates  4  and the apertures  8 ,  17  of the first end plate  2 . Thereby both the upper guiding element  7   a  and the lower guiding element  7   b  can guide the first end plate  2  laterally, whereas the load of the first end plate  2  is carried by the guiding rail  12 . The upper guiding element  7   a  and the lower guiding element  7   b  will also guide the heat exchanger plates  4  laterally by the external geometry  19  of the guiding elements  7   a ,  7   b  and the lower guiding element  7   b  will carry the load of the heat exchanger plates  4 . The load is transferred directly to the guiding rail  12  and further to the ground. The external geometry  10  of the lower portion of the upper guiding element  7   a  guides the heat exchanger plates  4  and serves a tilting protection for the heat exchanger plates  4 , when the plate heat exchanger  1  is open. 
         [0039]    It is also possible that the upper guiding element  7   a  fully or partially carries the load of the heat exchanger plates  4  by the external geometry  10 . 
         [0040]    In  FIGS. 5-6  the guiding element  7   a ,  7   b  and the guiding rail  12  is shown in more details, partial enlargement B and C of  FIG. 4 , as they are arranged in the plate heat exchanger  1 . One advantage of the suggested guiding profile  7   a ,  7   b  is that the same component can be used both as a carrying and guiding bar in the upper section of the plate heat exchanger  1  as well as carrying and guiding bar in the lower section of the plate heat exchanger  1 . The guiding rail  12  serves as a weight transferring element, which also enables that the lower outer guiding element  14   b  can be removed when the heat exchanger plates  4  and the first end plate  2  are tighten together so that a nut  6  can be arranged on the lowermost tightening bolt  5   b  in abutment with the first end plate  2  and to keep the plate heat exchanger  1  in the closed operational mode. 
         [0041]    As shown in  FIG. 1-2  the plate heat exchanger  1  can also be provided with a support device  15  to enable the plate heat exchanger  1  to be opened in an easy way, which support device  15  is provide at the free end of the tightening bolts  5   a ,  5   b  and kept in place by nuts  20 . The support device  15  extends between the two tightening bolts  5   a  and  5   b , and ensures that distance between the two tightening bolts  5   a  and  5   b  is invariable and that forces affecting the upper tightening bolt  5   a  are transferred to the ground. The further details of function and operation of the support device  15  will be described in connection with the description of the opening and closing process of the plate heat exchanger  1 . 
         [0042]    Now the opening of the plate heat exchanger  1  will be described. In  FIGS. 1 and 2  the plate heat exchanger  1  is operational mode. For enabling maintenance such as cleaning, repairing, replacing heat exchanger plates etc., the plate heat exchanger  1  can be opened. The nuts  20  are screwed off and the supporting device  15  and the outer guiding elements  14   a ,  14   b  are taken away of the tightening bolts  5   a ,  5   b . The nuts  6  arranged to the tightening bolts  5   a ,  5   b  are screwed off and the outer guiding elements  14   a ,  14   b  are again arranged onto the free parts of the tightening bolts  5   a ,  5   b  and pushed abutment against the inner guiding elements  13   a ,  13   b . The package of heat exchanger plates  4  and the first end plate  2  is still kept together by the further tightening bolts  5   c . The supporting device  15  is once again mounted onto the free parts of the upper and lower tightening bolts  5   a ,  5   b . The supporting device  15  is supported to the ground via the outer guiding element  14   b  and the guiding rail  12 . The nuts  20  are brought upon the tightening bolts  5   a ,  5   b  and tightened. The further tightening bolts  5   c  are demounted. As the tightening bolts  5   c  are released the first end plate  2  and the heat exchanger plates  4  may thereafter be moved along the guiding elements  7   a ,  7   b . Hereby an open mode of service of the plate heat exchanger  1  is attained, when the heat exchanger plates  4  are situated between the end plates  2 ,  3  may be separated for cleaning and one or several heat exchanger plates  4  may be taken out and eventually new ones put in without the need for demounting of the rest of heat exchanger plates  4 . Closing or tighten together the plate heat exchanger  1  into operational mode is executed in an analogous reversed way. 
         [0043]    The supporting device  15  is a bar, a plate iron or the like with a sufficient length to be able to hold the uppermost and lowermost tightening bolts  5   a ,  5   b  at a correct distance in relation to each other and at the same time in the open mode of service for the plate heat exchanger  1  to be able to serve as a supporting device  15  for the whole plate heat exchanger  1  together with the second end plate  2 . It further ensures that forces affecting the upper tightening bolt  5   a  are transferred to the ground via the lower tightening bolt  5   a.    
         [0044]    The guiding element  7   a ,  7   b  and the guiding rail  12  are preferably made of an extrudable material such as a plastic or aluminum profile, but can also be made of any other suitable manufacturing method or material. 
         [0045]    The invention is not limited to the embodiments described above and shown on the drawings, but can be supplemented and modified in any manner within the scope of the invention as defined by the enclosed claims.