Abstract:
A method for producing a heat exchanger in which the heat exchanger has a plurality of identically embodied guide baffles which form a helical guide for the composition and which are penetrated by heat exchanger tubes. For making through openings in the guide baffles for the heat exchanger tubes, a mounting device cooperates with a laser beam device. By making the through openings in the guide baffles that have already been provided with their final slope, the through openings can be adapted very precisely to the heat exchanger tubes. As a result, losses from overflow of the composition at the guide baffles are reduced, and the efficiency of the heat exchanger is increased.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based on German Patent Application 10 2004 061 354.0 filed on Dec. 21, 2004, upon which priority is claimed.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention relates to an improved method of and an apparatus for producing a heat exchanger for compositions in the candy-making industry.  
         [0004]     2. Description of the Prior Art  
         [0005]     From German Patent Disclosure DE 10 2004 028 528 A1, a heat exchanger is known which comprises a plurality of identically embodied guide elements that together form a helix. The guide elements are penetrated by tubes for a heating medium or cooling medium that are located parallel to the longitudinal axis of the housing jacket of the heat exchanger. The guide elements are embodied either with a steady curvature or in other words helically, or they also, in addition to guide portions that extend perpendicular to the longitudinal axis of the housing jacket, have guide portions that extend obliquely to the longitudinal axis of the housing jacket.  
         [0006]     To assure that a candy composition that must conventionally be heated will always follow the guide elements and not move from one side of the guide element directly to the other side in the region of the openings for the tubes, it is necessary to adapt the openings for the tubes at the guide elements as exactly as possible to the tubes themselves. This is problematic, because the regions of the guide elements that extend obliquely to the longitudinal axis of the heat exchanger require oval openings for the sake of freedom from gaps, and these openings, depending on the slope of the helix must be shaped differently from the inside outward. It would be conceivable, for the sake of the simplest possible production, to embody the openings as round bores with a large oversize. The resultant gaps existing between the openings of the tubes, because of the faster passage through them of the composition from the inlet side to the outlet side of the heat exchanger, reduce the efficiency. To increase the efficiency, it could be attempted that the gaps be welded, for instance. However, this goes against the demand for economical production and in practice is hardly feasible, because of the close arrangement of individual tubes.  
       OBJECT AND SUMMARY OF THE INVENTION  
       [0007]     It is therefore the object of the invention to furnish a method for producing a heat exchanger which makes especially high efficiency of a heat exchanger possible at reasonable cost. This object is attained by the characteristics of claim  1  essentially in that the openings for the tubes are not made in the guide elements until the applicable guide element has been put into its form required for the helical guide. As a result, the shape of the openings can be adapted exactly, or in other words with a minimal gap, to the tubes.  
         [0008]     It is especially advantageous to make the openings by means of a laser beam device, since this makes rational production possible. Advantageous refinements of the method of the invention, and an apparatus suitable for performing the method, are disclosed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of a preferred embodiment, taken in conjunction with the drawings, in which:  
         [0010]      FIG. 1  shows a heat exchanger in perspective and partly in section;  
         [0011]      FIG. 2  is a perspective view of an apparatus according to the invention for making the openings in a guide element;  
         [0012]      FIG. 3  shows the apparatus of  FIG. 2  from a different perspective; and  
         [0013]      FIG. 4  is a side view on the apparatus of  FIGS. 2 and 3  during the production of the openings in a guide element. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]     In  FIG. 1 , a heat exchanger  10  is shown, of the kind used in a candy-making industry for producing or processing such compositions as sugar/glucose solutions or the like. The heat exchanger  10  has a hollow-cylindrical housing jacket  11 , which is only partly visible in  FIG. 1 , for the sake of simplicity. On each of its face ends, the housing jacket  11  has a respective connection flange  12 ,  13 , which is connected to a respective closure piece  14 ,  15 . The closure pieces  14 ,  15 , which are bell-shaped, each have an inlet  16  and an outlet  17  for a heating or cooling medium. Also in the housing jacket  11 , near the connection flanges  12 ,  13 , there are an inlet neck  18  and an outlet neck  19  for the composition to be heated or cooled; these are shown only in simplified form in  FIG. 1 .  
         [0015]     A heat exchanger insert  20  can be inserted into the interior of the housing jacket  11 . The heat exchanger insert  20  has a tubular support element  21 , which is located centrally in the longitudinal axis of the housing jacket  11  and extends between the two connection flanges  12 ,  13 . The support element  21  may likewise have a flow of heating and cooling medium through it. In the space between the support element  21  and the housing jacket  1   1 , a plurality of heat exchanger tubes  23  are provided, which each extend parallel to one another and end in the connection flanges  12 ,  13 , which have suitable through bores for this purpose. The heating or cooling medium is transported inside the heat exchanger tubes  23 , specifically from the direction of the inlet  16  in the direction of the outlet  17 . Moreover, a helically embodied guide element  25  for the composition to be heated or cooled extends in the space between the support element  21  and the housing jacket  11 . The guide element  25  is adjoined in the region of the inlet neck  18  by an inlet adapter  22  and in the region of the outlet neck  19  by an outlet adapter  24 .  
         [0016]     The guide element  25 , in this exemplary embodiment, comprises many annularly or helically embodied guide baffles  26 , which adjoin one another and form the helical guide for the composition. To that end, the guide baffles  26  are welded together, for instance, at their narrow face ends  27  and are joined to the support element  21  on their inner circumference.  
         [0017]     In the exemplary embodiment, the disposition of the guide baffles  26  inside the housing jacket  11  is such that over the entire length of the heat exchanger  10  between the inlet adapter  22  and the outlet adapter  24 , there is the same pitch or slope, or in other words the same spacing between individual guide baffles  26 .  
         [0018]     In the guide baffles  26 , there are through openings  28 , corresponding to the disposition of the heat exchanger tubes  23 , so that the heat exchanger tubes  23  can be installed or positioned when the guide baffles  26  have been installed on the support element  21 . The various gaps between the through openings  28  and the heat exchanger tubes  23  are made as small as possible, so that the composition will be hindered from passing through the various gaps.  
         [0019]     It is noted in addition that in the view in  FIG. 1 , for the sake of clarity, only some of the heat exchanger tubes  23  are shown, while at the guide baffles  26  all the through openings  28  are shown.  
         [0020]     The heat exchanger  10  functions as follows: The composition to be heated or cooled passes via the inlet neck  18  into the space between the housing jacket  11  and the support element  21 . Since the inflow of the composition takes place under pressure, the composition moves from the inlet neck  18  to the outlet neck  19  within the helical courses that are defined by the guide baffles  26 . During the passage through the heat exchanger  10 , the composition to be heated or cooled is in contact with the heat exchanger tubes  23 , through which a corresponding heating medium or cooling medium flows, and the heating medium or cooling medium enters the heat exchanger  10  through the inlet  16  and is removed from it via the outlet  17 .  
         [0021]     For producing the heat exchanger  10  and in particular for producing the through openings  28  for the heat exchanger tubes  23  in the guide baffles  26 ,  FIGS. 2 through 4  will now be described. A mounting device  30  can be seen, which has an approximately rectangular base plate  31  and a mounting plate  32  that is joined to the base plate  31 . One through bore  33 ,  34  is made on the diametrically opposed sides in the base plate  31 , which makes it possible to flange the base plate  31  to an adapter of a turning gear (not shown). By means of the turning gear, the base plate  31  can be rotated in the direction of the arrow  36  in the same axis  35  in which the mounting plate  32  is also disposed.  
         [0022]     In the base plate  31 , in the region of each of the diametrically opposed broad sides, a respective slitlike milled recess or groove  38 ,  39  is embodied, spaced only slightly apart from the edge of the base plate  31 , and this milled recess is suitable for receiving the respective portion  41 ,  42  of a guide baffle  26  by its outer circumference. The mounting plate  32 , located in the middle between the two through bores  33 ,  34  and perpendicular to the base plate  31 , also has one milled recess or groove  43 ,  44  each on the respective sides facing toward the face ends  27  of the guide baffle  26 , for receiving the guide baffle  26  by its corresponding face end  27 . By means of the mounting device  30  described thus far, a guide baffle  26  can be positioned in its installed position that is required and contemplated in the heat exchanger  10 ; before it is installed in the mounting device  30 , the guide baffle  26  is provided with or preshaped with a suitable slope.  
         [0023]     To fix the guide baffle  26  in the mounting device  30 , or in its milled recesses  38 ,  39 ,  43 ,  44 , a rectangular fixation plate  45  is provided, which can be secured by means of screws to the mounting plate  32  that protrudes to the height of the central opening  46  in the guide element  26 . The fixation plate  45  protrudes into the opening  46  and thus positions the guide baffle  26  in the milled recesses  38 ,  39 ,  43 ,  44 .  
         [0024]     In  FIG. 4 , a laser beam device  50  is schematically represented. The laser beam device  50  generates a laser beam  51  for making the through openings  28  in the guide baffle  26 . The laser beam device  50  is movable by means of an actuator both in the direction of the double arrows  53 ,  55  and perpendicular to the plane of the drawing in  FIG. 4  in the region of the guide baffle  26  in which the through openings  28  are to be made. The making of the through openings  28 , for manufacturing reasons, because the through openings  28  are close to the apparatus and would collide with the laser head of the laser beam device  50 , are made in two successive work steps. In a first work step, first those through openings  28  that are located on a half sector  54  of the guide baffle (see  FIG. 2 ) are made. For each through opening  28 , the laser beam  51  is moved in the plane perpendicular to the axis  56  along a circular path whose diameter, taking appropriate assembly tolerances into account, is essentially equivalent to the diameter of the heat exchanger tubes  23 . Next, the guide baffle  26 , along with the mounting device  30 , is rotated by 180° about the axis  35 , so that the other half sector  55  can be machined accordingly. Once the through openings  28  have been made in both half sectors  54 ,  55 , the guide baffle  26  can be removed from the mounting device  30 , so that the through openings  28  can be made in the next guide baffle  26 .  
         [0025]     The installation of the guide baffles  26  in the heat exchanger  10  is done by first threading the individual guide baffles  26  onto the tubular support element  21 ; the diameter of the support element  21  is adapted to the width of the opening  46  in the guide baffles  26 . As a result, a prealignment of the guide baffles  26  can be attained. Next, some of the heat exchanger tubes  23  are threaded through the through openings  28 , as a result of which, and also because of the exact axial alignment of the laser-made through openings  28 , the final alignment of the guide baffles  26  is obtained. Then, the thus-aligned guide baffles  26  are joined, in particular welded, to the support element  21 . Finally, the remaining heat exchanger tubes  23  can be installed, and the thus-formed unit, once it has been provided with the inlet adapter  22  and the outlet adapter  24 , can be thrust into the housing jacket  11 .  
         [0026]     The foregoing relates to a preferred exemplary embodiment of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.