Patent Abstract:
An apparatus removing material accumulated on the exterior surfaces of adjacent heat exchanger plates arranged side-by-side in a spaced relationship in a bulk material heat exchanger and a bulk material heat exchanger incorporating the apparatus is provided. In one aspect, the apparatus develops vibratory shock waves through each coil to dislodge material that has accumulated on the surfaces of the heat exchanger plates. In another aspect, the apparatus translates each heat exchanger plate in a sequential back-and-forth motion to create a shearing effect in material that has accumulated between the adjacent surfaces of heat exchanger plates. In one aspect, the apparatus includes a driven cam and a cam follower, where the cam or cam follower includes a profile to achieve the desired motion of each heat exchanger plate.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional of application Ser. No. 10/775,381, filed Feb. 10, 2004, now U.S. Pat. No. 7,093,649 which is incorporated herein in entirety by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to flat heat exchanger plates for use in heat exchangers. More particularly, relating to a flat exchanger plates, a method and apparatus of cleaning flat heat exchanger plates and a bulk material heat exchanger using the same. 
   2. Description of the Prior Art 
   Typically, in processing bulk materials, such as pellets, granules, powders or the like, heat exchangers are employed to either cool or heat the material during the processing thereof. The heat exchangers employed consist of an array of heat exchanger plates arranged side-by-side in spaced relationship and are positioned in an open top and open bottom housing. The like ends of each heat exchanger plate are connected to together by means of a manifold and a heat exchange medium, such as water, oil, glycol or the like is caused to flow through the plates. Generally, the material treated by the heat exchanger is allowed to gravity flow through the housing and the spaces between the spaced plates. During the progression of the material through the heat exchanger, the material is caused to contact the walls of the plates thereby effecting heat transfer between the material and the plates. The rate at which the material flows through the heat exchanger and ultimately across the plates can be controlled by restricting the flow of the material at the outlet of the heat exchanger. 
   The heat exchanger plates are constructed by attaching metal sheets together along the edges thereof and this is normally accomplished by seam welding the sheets together to form a fluid tight hollow plate. Heretofore, heat exchanger plates have been constructed to operate under internal pressure caused by pumping the heat exchange medium through the plate. To resist internal pressure and to prevent the sides of the plates from deforming, depressions or dimples are formed along the plate. An example of similar heat exchanger plates and their use are described in U.S. Pat. No. 6,328,099 to Hilt et al. and U.S. Pat. No. 6,460,614 to Hamert et al. 
   During the normal operation of the heat exchanger the bulk material tends to accumulate within the dimples or spot welds and continues to collect to a point where the efficiency of the heat exchanger is greatly reduced and must be cleaned to remove the material residue from the dimples and surrounding exterior surface of the plates. In some circumstances, the material is allowed to collect to a point where the material will bridge between adjacent plates; this not only reduces the heat transfer efficiency of the heat exchanger, but also restricts the flow of the material through the heat exchanger. These circumstances are very undesirable because the operation of heat exchanger must be shut down for a period of time to clean the plates, which many times means the material production line is also shut down, resulting in loss of production and ultimately loss in profits. 
   Therefore, a need exists for a new and improved flat heat exchanger plate that can be used for bulk material heat exchangers which reduces the tendency for the material to accumulate on the plates. In this regard, the present invention substantially fulfills this need. In this respect, the flat heat exchanger plate according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of increasing the efficiency of bulk material heat exchangers and reducing down time thereof. 
   SUMMARY OF THE INVENTION 
   In general in one aspect, an apparatus for removing accumulated material between adjacent heat exchanger plates arranged side-by-side in a spaced relationship in a bulk material heat exchanger is provided. The apparatus includes a support member for supporting the heat exchanger plates and a lift means for lifting each heat exchanger plate, the lift means operable to raise each heat exchanger plate a predetermined distance and lower each heat exchanger plate the predetermined distance to cause material that has accumulated on the exterior surfaces of the heat exchanger plates to be dislodged from the exterior surfaces. 
   In general in another aspect, an apparatus for removing material accumulated on the exterior surfaces of adjacent heat exchanger plates arranged side-by-side in a spaced relationship in a bulk material heat exchanger is provided. The apparatus includes a support member for supporting the heat exchanger plates and a lift means for lifting each heat exchanger plate, the lift means operable to raise each heat exchanger plate a predetermined distance and lower each heat exchanger plate the predetermined distance to cause material that has accumulated on the exterior surfaces of the heat exchanger plates to be dislodged from the exterior surfaces. The lift means operates to lift the support member carrying each heat exchanger plate therewith it and to abruptly drop the support member the predetermined distance to develop a shock wave through each plate heat exchanger 
   In general in another aspect, an apparatus for removing material accumulated on the exterior surfaces of adjacent heat exchanger plates arranged side-by-side in a spaced relationship in a bulk material heat exchanger is provided. The apparatus includes a support member for supporting the heat exchanger plates and a lift means for lifting each heat exchanger plate, the lift means operable to raise each heat exchanger plate a predetermined distance and lower each heat exchanger plate the predetermined distance to cause material that has accumulated on the exterior surfaces of the heat exchanger plates to be dislodged from the exterior surfaces. The lift means includes at least one cam, a motor operating to rotate the at least one cam, and at least one cam follower in rolling contact with at least one cam. 
   In general in another aspect, an apparatus for removing material accumulated on the exterior surfaces of adjacent heat exchanger plates arranged side-by-side in a spaced relationship in a bulk material heat exchanger is provided. The apparatus includes a support member for supporting the heat exchanger plates and a lift means for lifting each heat exchanger plate, the lift means operable to raise each heat exchanger plate a predetermined distance and lower each heat exchanger plate the predetermined distance to cause material that has accumulated on the exterior surfaces of the heat exchanger plates to be dislodged from the exterior surfaces. The lift means further includes a plurality sleeves each open at both ends with one each positioned through each heat exchanger plate such that the open ends of each of said plurality of sleeves are in cooperating alignment with one another. A cam follower attached to each of the plurality of sleeves and a plurality of cams spaced along the support member and in rolling contact with a respective cam follower. A motor is drivingly coupled to the support member. 
   There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. 
   Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of presently preferred, but nonetheless illustrative, embodiments of the present invention when taken in conjunction with the accompanying drawings. In this respect, before explaining the current embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction, the materials of construction or to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting. 
   As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
   For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
       FIG. 1  is a side elevation view of an embodiment of flat heat exchanger plate of the present invention. 
       FIG. 2  is an isometric view of the preferred embodiment of the bulk material heat exchanger constructed in accordance with the principles of the present invention in use with the flat heat exchanger plate of the present invention. 
       FIG. 3   a  is a cross sectional view of an end of an embodiment of the flat heat exchanger plate of the present invention illustrating one possible method of adjoining the sheets of the plate. 
       FIG. 3   b  is a cross sectional view of an end of an embodiment of the flat heat exchanger plate of the present invention illustrating a second possible method of adjoining the sheets of the plate. 
       FIG. 3   c  is a cross sectional view of an end of an embodiment of the flat heat exchanger plate of the present invention illustrating a third possible method of adjoining the sheets of the plate. 
       FIG. 3   d  is a cross sectional view of an end of an embodiment of the flat heat exchanger plate of the present invention illustrating a fourth possible method of adjoining the sheets of the plate. 
       FIG. 3   e  is a cross sectional view of an end of an embodiment of the flat heat exchanger plate of the present invention illustrating a fifth possible method of adjoining the sheets of the plate. 
       FIG. 4  illustrates a pressure resistor and a possible attachment method thereof to the flat heat exchanger plate of the present invention. 
       FIG. 5   a  illustrates a pressure restraint member and a possible attachment method thereof to the flat heat exchanger plate of the present invention. 
       FIG. 5   b  illustrates a pressure restraint member and a possible alternate attachment method thereof to the flat heat exchanger plate of the present invention. 
       FIG. 5   c  illustrates an alternate pressure resistor attached to a single side of the flat heat exchanger plate of the present invention. 
       FIG. 5   d  illustrates the pressure resistor of  FIG. 5   c  and a possible arrangement method thereof to the flat heat exchanger plate of the present invention. 
       FIG. 5   e  illustrates the pressure resistor of  FIG. 5   c  used as a pressure restraint member and a possible attachment method thereof to the flat heat exchanger plate of the present invention. 
       FIG. 6   a  is a cross sectional view taken across a flow diverter of the plate in  FIG. 1 . 
       FIG. 6   b  is a cross sectional view taken across an alternate flow diverter of the plate in  FIG. 1 . 
       FIG. 6   c  is a cross sectional view taken across an alternate flow diverter of the plate in  FIG. 11 , discussed below. 
       FIG. 7  is a side elevation view of an alternate embodiment of the flat heat exchanger plate of the present invention. 
       FIG. 8   a  is a cross sectional view taken through a flow diverter of the plate in  FIG. 7 . 
       FIG. 8   b  illustrates an alternate embodiment of  FIG. 8   a.    
       FIG. 9  is a side elevation view of the tapered embodiment of the flat heat exchanger plate of the present invention. 
       FIG. 10   a  is a cross sectional view of the plate in  FIG. 9 . 
       FIG. 10   b  illustrates an alternate embodiment of  FIG. 10   a.    
       FIG. 11  is a side elevation view of an alternate embodiment of flat heat exchanger plate of the present invention. 
       FIG. 12  is a front elevation view of the flat heat exchanger plate of  FIG. 11 . 
       FIG. 13   a  is an isometric view of an alternate embodiment of a combined flow diverter and pressure resistor of the present invention. 
       FIG. 13   b  is a front elevation view of an alternate embodiment of the flat heat exchanger plate of the present invention. 
       FIG. 13   c  is an isometric view of an alternate combined flow diverter and pressure resistor of the plate in  FIG. 13   b.    
       FIG. 14  is a front elevation view of an alternate embodiment of the flat heat exchanger plate of the present invention. 
       FIG. 15  is a cross sectional view of the plate in  FIG. 14 . 
       FIG. 16  illustrates the method of incorporating a removable seal between adjacent flat heat exchanger plates. 
       FIG. 17  is a side elevation view of an embodiment of the flat heat exchanger plate of the present invention illustrating the typical placement of support holes for supporting the plate. 
       FIG. 18  is a cross sectional view of one support hole of  FIG. 17 . 
       FIG. 19  is a side elevation view of an embodiment of the flat heat exchanger plate of the present invention illustrating a typical placement of location lugs, indents, support lugs and lifting lug for the plate. 
       FIGS. 20   a  and  20   b  illustrate a method of automated cleaning of the flat heat exchanger plates of the present invention. 
       FIGS. 21   a ,  21   b  and  21   c  illustrate an alternate method of automated cleaning of the flat heat exchanger plates of the present invention. 
       FIG. 22   a  illustrates an additional alternate method of automated cleaning of the flat heat exchanger plates of the present invention, where a plurality of cam elements are positioned along the length of a support bar. 
       FIG. 22   b  illustrates one possible cam arrangement for use in the method of automated cleaning of the flat heat exchanger plates illustrated in  FIG. 22   a.    
       FIG. 22   c  illustrates a second one possible cam arrangement for use in the method of automated cleaning of the flat heat exchanger plates illustrated in  FIG. 22   a.    
       FIG. 23  illustrates an example of a cam arrangement to provide horizontal, back and forth movement of the flat heat exchanger plates. 
       FIG. 24  illustrates an example of a cam arrangement to provide horizontal side-to-side movement of the flat heat exchanger plates. 
   

   The same reference numerals refer to the same parts throughout the various figures. 
   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings, and particularly to  FIGS. 1-2 , a preferred embodiment of the flat heat exchanger plate of the present invention is shown and generally designated by the reference numeral  10 . 
   In  FIGS. 1 and 2  a new and improved flat heat exchanger plate  10  of the present invention for the purpose of increasing the efficiency of bulk material heat exchangers and reducing down time thereof is illustrated and will be described. More particularly, in  FIG. 1 , the flat heat exchanger plate  10  has a flat, generally rectangular metal body  12  having two opposing side sheets  14 , two opposing longitudinal edges  16 , and two opposing transverse edges  18 . The two side sheets  14  are sealed to each other along the borders of the two longitudinal and two transverse edges  16  and  18  defining an open interior space.  FIGS. 3   a - 3   d  illustrate possible methods of seaming the edges of the flat heat exchanger plate  10 . Heat exchange medium inlet and exit nozzles  20  and  22  are provided in fluid communication with the open interior space and can be arranged for example along a common longitudinal edge  16 . 
   Each side sheet  14  is substantially smooth and free of depressions and/or dimples or the like. The phrase “substantially smooth” is to be defined in the context of this application for U.S. Letters Patent as free from ridges, depressions, and dimples or the like created in the sides of the flat heat exchanger plate during the manufacture thereof. 
   Prior art heat exchanger plates are manufactured with dimples and/or depressions formed on the sides thereof and welded together to increase the resistance of the sides from bowing outward due to a positive internal operating pressure created by pumping a heat exchange medium through the plate. These dimples are a drawback to prior art plates because in service bulk material tends to accumulate in these dimples which has a negative two fold effect. First, the heat transfer between the bulk material and the plate is reduced by a loss of effective surface area of the plate and second the bulk material may be allowed to accumulate to a point where the material bridges between adjacent plates thereby impeding the flow of the material through the heat exchanger. Once this occurs, the heat exchanger must be removed from service and cleaned, which results in undesirable down time of the material production line. To over come the drawbacks of the prior art, the flat heat exchanger plate  10  of the present invention is designed to operate under a negative internal pressure, thereby eliminating the need to create dimples on the sides of the plate. 
   Turning to  FIG. 2 , numerous flat heat exchanger plates  10  are illustrated in an exemplary in-use arrangement positioned within a typical bulk material heat exchanger  24 . The flat heat exchanger plates  10  are arranged side-by-side in a spaced relationship within the shell of the bulk material heat exchanger  24 . The inlet nozzle  20  of each plate  10  is connected to a common heat exchange medium supply manifold  26  and the exit nozzle  22  of each plate is also connected to a common heat exchange medium return manifold  28 . The inlet nozzle  20  and the exit nozzle  21  can be formed to any suitable shape, such as but not limited to a rectangle or a circle. In operation, a vacuum source is provided at the heat exchange return manifold  28  and the flow of the heat exchange medium is indicated by arrows  30 , where the heat exchange medium enters the supply manifold  26  and is distributed to each of the inlet nozzle  26  of each plate  10 . The heat exchange medium is then drawn up and through each plate  10  and ultimately out of the heat exchange medium return manifold  28 . Arrows  32  indicate the flow of the bulk material, and the material flows through the heat exchanger and across the plates  10 , typically under the force of gravity. With this arrangement, the bulk material heat exchanger  24  operates as a counter flow type heat exchanger. 
   The flat heat exchanger plate  10  as indicated above, is designed to operate under a negative internal pressure or vacuum as low as about 10 psi (70 kPa) on a vacuum gage. To prevent the side sheets  14  of the flat heat exchanger plate  10  from collapsing at least one pressure resistor member  34  is positioned and strategically arranged within the interior space of the plate. During non-operational periods of the plate  10 , a positive internal pressure may be present due to the hydrostatic pressure of the heat exchange medium present within the plate in a static state. To prevent inflation or deforming of the sides of the plate  10 , at least one pressure restraint member  36  can be included and is positioned and strategically arranged within the interior space of the plate. 
   At least one flow diverter  38  is positioned within the flat heat exchanger plate  10  to a create flow passage for the circulating heat exchange medium to flow through. Preferably, flow diverters  38  are arranged to create a serpentine-like flow path for the heat exchange medium. The flow diverters  38  can also aid the pressure resistor members  34  in preventing the sides of the plate  10  from collapsing. 
     FIG. 4  illustrates a pressure resistor member  34  positioned between the interior surfaces  40  of the side sheets  14  of the flat heat exchanger plate  10 . The pressure resistor member  34  is generally cylindrical and is attached at one end to one interior surface  40  of a single side sheet  14 . Preferably, the pressure resistor member  34  is attached at one end to the interior surface  40  by a weld  42  with the opposite end of the pressure resistor member free from attachment to the opposing interior surface of the other side sheet. In a preferred embodiment, the pressure resistor member  34  is of a length equal to the distance between the interior surfaces  40  of the plate side sheets  14 . In the manufacture of the plate  10 , a predetermined number and arrangement of pressure resistors  34  are first attached in a desired pattern to the interior surface  40  of the side sheets  14  before the side sheets are assembled with the plate  10 . 
   Turning to  FIG. 5   a , one possible embodiment of a pressure restraint member  36  is illustrated and will be described. The pressure restraint member  36  is attached at one end to one interior surface  40  of one side sheet  14  by weld  44 . The opposite end of the pressure restraint member is plug welded  46  to the opposite side sheet  14  through a hole  48  formed therethrough and dressed flush with the exterior surface  54  of the side sheet. In this embodiment, the pressure restraint member  36  is cylindrical in shape and is of a length equal to the distance between the interior surfaces  40  of the side sheets  14 . 
   Now turning to  FIG. 5   b , an alternate embodiment of a pressure restraint member  36  is illustrated and will be described. The pressure restraint member  36  is attached at one end to one interior surface  40  of a side sheet  14  by a weld  44 . In this embodiment, the pressure restraint member  36  is of a length to pass through a hole  50  formed through the opposite side sheet  14  and is welded  52  around the hole  50 . In this application, the weld  52  and the end of the pressure restraint member are dressed flush with the exterior surface  54  of the side sheet  14 . 
   Referring to  FIGS. 5   c - 5   e , an alternate embodiment of a pressure resistor member  34  and a pressure restraint member  36  is illustrated and will be described. The pressure resistor member  34  and the pressure restraint member  36  have a cylindrical body, closed at one end  56  and a flanged end  58 . Application of the pressure resistor member  34  is illustrated in  FIG. 5   d , where the flanged end  58  is attached to the interior surface  40  of one side sheet  14  by a circular weld  60 . The pressure resistors  34  can be attached to the interior surfaces  40  of the side sheets  14  in an alternating pattern as illustrated. Application of the pressure restraint member  36  is illustrated in  5   e , where the flanged end  58  is attached to the interior surface  40  of one side sheet  14  by a circular weld  60 . Then on assembly with the other side sheet  14 , the cylindrical body  56  is weld thereto by weld  62 . The pressure restraint member s  36  can be attached to the interior surfaces  40  of the side sheets in an alternating pattern as illustrated. 
   Turning now to  FIG. 6   a , which is a cross sectional view of the flat heat exchanger plate  10  as illustrated in  FIG. 1 . This figure shows an example of one possible form of a flow diverter  38  positioned within the plate  10  and between the side sheets  14 . In this example, the flow diverter  38  is a strip of material having a bend of approximately 90 degrees along a centerline thereof. The flow diverter  38  includes a plurality of holes  64  formed therethrough along the centerline thereof. The holes  64  allow the flow diverter  38  to be positioned about an arrangement of pressure resistors  34  and/or pressure restraint members  36 . Referring back to  FIG. 1 , which illustrates the placement of multiple flow diverters  38  about the pressure resistors  34  and pressure restraint member s  36  to create a serpentine flow path for the heat exchange medium. The positioning of the flow diverters  38  as illustrated is for exemplary purposes only as the flow diverters can be arranged in any manner to create a desired flow path for the heat exchange medium. 
     FIG. 6   b  illustrates an example of a combined flow diverter and pressure resistor  38  positioned within the flat heat exchanger plate  10  between the side sheets  14 . In this example, the combined flow diverter and pressure restraint  38  is a strip of material having opposed edges bent orthogonal to the side sheets  14  to form two legs  15 . These legs act as pressure resistors to prevent the collapse of the plate  10  when operated under a negative pressure. The diagonal web  17  includes a plurality of locating holes  64 , and creates to flow passages  19  for the heat exchange medium. 
     FIG. 6   c  illustrates an additional example of a combined flow diverter and pressure resistor  38  in the form of a corrugated formed sheet of material positioned within the flat heat exchanger plate  10  and secured to the interior surfaces  40  of the side sheets  14 . 
   Turning to  FIGS. 7 ,  8   a  and  8   b  an alternate embodiment of the flat heat exchanger plate  10  and flow diverters  38  of the present invention is illustrated and now will be described. In this embodiment, the flow diverters  38  are formed from a solid rod or tube, which are bent and positioned within the plate  10  to create a desired heat exchange medium flow path. The pressure resistors  34  and the pressure restraint member s  36  are strategically positioned and attached to the side sheets  14  of the plate  10  to aid in the correct placement of the formed flow diverters  38 . Preferably, the pressure resistors  34  and restraints  36  are positioned to alternate from side to side of the flow diverters  38 , as illustrated in  FIG. 7 .  FIG. 8   a  is an enlarged partial cross section of the plate  10  illustrated in  FIG. 7  and this figure shows a flow diverter formed from a solid rod and illustrates the method of positioning the pressure resistors  34  and/or restraints  36  on opposite sides of the flow diverter  38  to aid in the positioning and retention thereof.  FIG. 8   b  illustrates an alternate embodiment of the flow diverter  38  illustrated in  FIG. 8   a . In this embodiment, the flow diverter is a tube. The flow diverters  38  illustrated in  FIGS. 7 ,  8   a  and  8   b  are of a material having a circular cross section for exemplary purposes only and should not limit the possibility of using material of other cross sectional shapes. 
   Referring now to  FIGS. 9 ,  10   a  and  10   b , which illustrate an additional embodiment of the flat heat exchanger plate  10  of the present invention. In this embodiment the thickness of the plate  10  decreases in the direction from one transverse edge to the second transverse edge. Preferably, the thickness of the plate  10  decreases in the direction of the flow of bulk material across the coil. Preferably in this particular embodiment incremental steps  66  decrease the thickness of the plate  10 . Most preferably, the steps  66  and thickness of the plate  10  correspond with the various diameters of rod or tube used for the flow diverters  38 .  FIG. 9  also illustrates an additional possible arrangement of the flow diverters  38  to create a serpentine flow path for the heat exchange medium. As in all of the aforementioned embodiments of the flat heat exchanger plate  10 , the flow diverters in this embodiment can aid the pressure resistors  34  in preventing the side sheets  14  of the plate  10  from collapsing. During the manufacture of this embodiment of the flat heat exchanger plate  10  the longitudinal edges  16  are cut to match the step profile of the side sheets  14  of the plate. Preferably, the longitudinal edges  16  are laser cut to match the step profile of the side sheets  14 . 
     FIG. 10   a  is a side elevation view illustrating an example of one method of creating a tapered flat heat exchanger plate  10 . In this example, the side sheets  14  of the plate  10  are formed by overlapping sections of sheet metal  68 , as illustrated, which are then welded together. The thickness of the flow diverters  38  are equal to the distance between the interior surfaces  40  of the side sheets  14  for each step  66  of the plate  10 . For exemplary purposes only, the flow diverters in this figure are illustrated as solid rods. 
     FIG. 10   b  illustrates a side elevation view illustrating an example of a second method of creating a tapered flat heat exchanger plate  10 . In this example, a single sheet is used for each side sheet  14  and the sheet is bent inward at various positions along the length thereof to create the required stepped profile of the side sheet. The thickness of the flow diverters  38  are equal to the distance between the interior surfaces  40  of the side sheets  14  for each step  66  of the plate  10 . For exemplary purposes only, the flow diverters in this figure are illustrated as tubes. 
   Referring now to  FIGS. 11 ,  12  and  13 , which illustrate a third embodiment of the flat heat exchanger plate  10  of the present invention and an additional example of a flow diverter assembly  38  for use with a tapered or parallel plate. The flow diverter assembly  38  of this embodiment includes a plurality of tapered flow diverter strips  70  which are interlocked with a plurality of flow control strips  72 . Preferably, the flow control strips  72  and the tapered flow diverter strips  70  are interlocked orthogonal to each other. The flow control strips  72  include a plurality of reduced sections  74 , which are formed to be positioned between adjacent tapered flow diverter strips  70  and serve to control the amount of heat exchange medium that passes each flow control strip. The flow diverter  38  of this embodiment is also used to prevent the tapered plate  10  from collapsing under negative operating pressure. Pressure restraint members  36  (not illustrated) may also be used in the same manner as described previously to prevent inflation of the plate  10  and to help position the flow diverter  38  within the plate. 
   Referring to  FIGS. 13   b  and  13   c , which illustrate a fourth embodiment of the flat heat exchanger plate  10  of the present invention and an additional example of a plurality of flow diverters  38  for use with tapered or parallel flat heat exchanger plate. The flow diverter  38  of this example is a tapered or parallel strip of material formed in a serpentine shape and includes a heat exchange medium flow control leg  39 . The flow control leg  39  restricts the flow of heat exchange medium into each chamber  41  to ensure an even flow rate of heat exchange medium within each chamber across the plate. The flow diverter  38  of this example is also used to prevent the plate  10  from collapsing under negative operating pressure. In addition to the flow diverters  38 , pressure restraint members  36 . not illustrated, can be used in the same manner as previously described to prevent inflation of the plate  10  and to aid in the positioning of the flow diverters  38  within the plate. 
   Turning to  FIGS. 14 and 15  a fifth method of creating a tapered flat heat exchanger plate  10  is illustrated. The flat side sheets  14  are in parallel planes and increase in width in a direction from one transverse edge  18  of the plate  10  to second transverse edge  18  of the plate. Preferably, the thickness of the plate  10  remains constant along the length of the plate. The gradual increase in width of the plate  10  creates a greater volume between adjacent plates in a bulk material heat exchanger, which releases pressure build-up in particulate material flowing through the heat exchanger. The flow diverters  38  of this example are of an open channel material having a closed side  76  and an open side  78  that includes a pair of flanges  80 . The flat heat exchanger plate  10  is constructed by first attaching a plurality of flow diverters  38  to the interior surface  40  of one side sheet  14  by welds  82 . The plurality of flow diverters  38  are attached to the side sheet  14  in a desired pattern to create a flow path for the heat exchange medium. Then the second side sheet  14  is attached to the plate  10  and the flow diverters  38  by welds  84  from the exterior side of the second sidewall. Preferably, the welds are laser welded. This method of construction provides for the placement of the flow diverters  38  within the plate and allows the flow diverters to function as pressure resistors and restraints. 
   Now turning to  FIG. 16 , a removable seal  86  may be positioned between adjacent flat heat exchanger plates  10  to retain the flow of material  88  therebetween. The seal may be removed to help facilitate the cleaning of the plates  10  or by adjusting the vertical angle of the seal to control the flow of material  88  between the plates. 
   Referring to  FIGS. 17 and 18 , which illustrate a typical placement of support holes  90  through the flat heat exchanger plate  10 . The support holes  90 , which may be of any desired shape, are formed through both side sheets  14 . A tubular sleeve  91  is placed in the support holes  90  then welded to both side sheets  14  and then dressed flushed with the exterior surfaces of the side sheets. The support holes  90  are typically used in supporting the flat heat exchanger plate  10  within a heat exchanger. 
   Now turning to  FIG. 19 , which illustrates the capability of incorporating the placement of location lugs  92 , which extend from the ends of the flat heat exchanger plate  10 , indents  94  formed into the ends of the plate, support lugs  96  extending from the edges of the body of the plate and a lifting lug  98  extending from the top of the plate. Currently, plate heat exchangers are manufactured with supports below the plates which can impede the flow of bulk material and also increase the overall height of the heat. The incorporation of location lugs  92 , indents  94 , support lugs  96 , or a lifting lugs  98  eliminates the need for the supports below the plates  10  and improves the flow path for the bulk material. The overall height of the heat exchanger can be reduced correspondingly. 
   Referring to  FIGS. 20   a  and  20   b , an additional embodiment the flat heat exchanger plate  10  is illustrated and will be described. In this embodiment, the flat heat exchanger plate  10  is designed and manufactured such that upon removal of the negative operating pressure the flat heat exchanger plate sides  14  will slightly inflate due to a positive internal pressure created exerted by the heat exchange medium. Isolating the vacuum source and allowing the heat exchange medium to develop a desired hydrostatic pressure within the flat heat exchanger plates  10  can achieve the slight inflating of the plate coil sides  14 . Upon reestablishing the negative operating pressure, the flat heat exchanger plate sides  14  return to a non-inflated position. Preferably, the hydrostatic pressure is allowed to reach a about 5 PSI (34 kPa) and is only applied for a short duration. The duration is at least 1 second. Preferably the duration is from about 1 to about 10 seconds and most preferably, the duration is about 5 seconds. An automated pulsing system  100  can be incorporated in the heat exchange medium system  102  to cause the inflation-deflation cycle of the flat heat exchanger plates  10  at a predetermined frequency. 
   Incorporating the above cyclic inflation of the flat heat exchanger plates  10  in, for example a bulk material heat exchanger would be beneficial in processing fine particulate materials which tend to bridge across narrow spaces such as the gaps between adjacent flat heat exchanger plates, which creates blockages in the flow of the material. By inflating the flat heat exchanger plate sides  14  by a small fraction of an inch the gap between adjacent flat heat exchanger plate decreases thus compressing any bulk material in the gap. On returning the flat heat exchanger plate sides  14  to the non-inflated position, the gap between adjacent flat heat exchanger plate increases to the normal operation gap and the compressed bulk material is dislodged from the sides. This system provides for the automated, self-cleaning of flat heat exchanger plates  10 , which reduces operating costs and service time of the flat heat exchanger plates. 
   In an additional embodiment of the flat heat exchanger plate system of providing automated, self-cleaning flat heat exchanger plate  10  is illustrated in  FIGS. 21   a ,  21   b  and  21   c . In this embodiment, the self-cleaning system includes a lift means  106  for lifting the flat heat exchanger plate  10  to aid in the removal of any bulk material that has accumulated on the exterior surfaces of the flat heat exchanger plate. In one example, the flat heat exchanger plates  10  are supported on a bar  104  passing through sleeves  91 , which can be extended as illustrated to maintain the flat heat exchanger plate spacing. Referring back to  FIG. 2 , a flexible connection is incorporated between the flat heat exchanger plate inlet nozzles  20  and the inlet manifold  26 , and a similar flexible connection is incorporated between the flat heat exchanger plate exit nozzles  22  and the outlet manifold  28 . In  FIGS. 21   a  and  21   b , the ends of the bar  104  are supported by the casing of the bulk material heat exchanger  24 . The lift means  106  for lifting and rapidly dropping the bar  104  and the flat heat exchanger plates  10  is attached to the bar. The lift means  106  would raise the bar  104  off of its supports  105  by a fraction of an inch, as illustrated in  FIG. 21   a  and then allowed to fall under the effect of gravity back onto the supports as illustrated in  FIG. 21   b . By the lift means  106 , the flat heat exchanger plates  10  supported by the bar  104  are raised and dropped developing a shock wave through the flat heat exchanger plates. The resultant shock wave will dislodge any present bulk material blockage between adjacent flat heat exchanger plates  10 . 
   The lift means  106  could incorporate, for example a cam  108  that is driven by motor  110 . The cam  108  is in contact with the cam follower  112  attached to the end  114  of the bar  104 . The cam  108  can include a gradual lift profile about a predetermined number of degrees of rotation and a flat profile about a predetermined number of degrees of rotating.  FIG. 21   c  illustrates an example of a cam profile that could be used. The lift profile of the cam  108  will gently raise the support bar  104  and the flat heat exchanger plates  10  to a maximum predetermined lift that is a fraction of an inch. The flat profile  109  of the cam  108  will cause the bar  104  to free fall under the force of gravity the distance it was originally raised causing the bar to impact its support  105 , thereby forming a shock wave through the flat heat exchanger plates  10 . 
   Referring to  FIGS. 22   a ,  22   b  and  22   c , an additional example of the lift means  106  is illustrated and will be described. A cam  116  for each flat heat exchanger plate  10  can be incorporated into the support bar  104  and a cam follower  118  can be incorporated into each sleeve  91 . Upon rotation of the support bar  104 , for example by attaching an end  114  of the support bar to the shaft of a motor, the flat heat exchanger plates  10  are raised and lowered based upon the profile of each cam  116 . Preferably, the maximum lift of each cam  116  is sequentially offset so that each flat heat exchanger plate  10  will be raised and lowered in predetermined sequence thus creating a shearing effect in the material between each adjacent flat heat exchanger plate. Turning to  FIG. 22   b , the cam profile of the cam  116  can include a steep profile section  120  which would cause the flat heat exchanger plate  10  to fall under the force of gravity a predetermined distance in accordance with the profile section  120 . This fall would send a shock wave through the flat heat exchanger plate  10  and aid in the removal of the material from of the exterior surface thereof. 
     FIG. 22   c  illustrates an additional example of a cam profile for the cam  116  that could be used. In this example, the flat heat exchanger plates  10  would be raised and lowered in a predetermined sequence thus creating a shearing effect the material between each adjacent flat heat exchanger plate. The incorporation of a scraper element  122  into the bearing surface of the sleeve  91  would act to keep the surface of the cam  116  clear of material debris that could impede the operation of the cam. 
   Referring to  FIG. 23 , which illustrates an example of a cam arrangement including an eccentric cam  116  and cam followers  118  incorporated into the sleeve  91  of a plate coil. In this example, upon rotation of the support bar  104  the cam followers  118  would follow the profile of the cam  116  and flat heat exchanger plate  10  would translate horizontally back and forth. Such as described above a plurality of cams  116  would be incorporated along the length the support bar  104  with the maximum lift of each cam  116  offset from each other to create a shearing effect in material between each adjacent flat heat exchanger plate. 
   Referring to  FIG. 24 , which illustrates an additional cam arrangement example including a plurality of lateral cams  116  cut into the support bar  104  and a cam follower  118  incorporated into the sleeve  91  of each flat heat exchanger plate  10 . In this example, upon rotation of the support bar  104  the cam follower  118  would follow the profile of the lateral cam  116  cut into the support bar  104  and the flat heat exchanger plates  10  would translate horizontally from side-to-side in unison. In addition, the sleeves are extended to provide spacing for adjacent flat heat exchanger plates  10 . The side-to-side, unison movement of the plate coils  10  aids in dislodging bulk material accumulated between adjacent flat heat exchanger plates. 
   A method of automated cleaning of the exterior surfaces of adjacent flat heat exchanger plate  10  is provided and includes the steps of providing at least two flat heat exchanger plates  10  arranged side-by-side in a spaced relationship, wherein the flat heat exchanger plates include a heat exchange medium inlet nozzle and an exit nozzle  20  and  22 . Attaching the heat exchange medium inlet  20  and exit nozzles  22  to a heat exchange medium supply system  102 , wherein the supply system includes a vacuum source which is attached to the heat exchange medium exit nozzles for creating a negative operating pressure within the flat heat exchanger plates. Isolating the vacuum source allowing the heat exchange medium to develop a predetermined desired hydrostatic pressure within the flat heat exchanger plates  10  to slightly inflate the flat heat exchanger plates to reduce the space between the flat heat exchanger plates and compress any bulk material that is accumulated on the exterior surfaces of the sides of the flat heat exchanger plates. And reconnecting the vacuum source to reestablish the negative operating pressure and thus deflating the flat heat exchanger plates  10  to increase the space between the plates and dislodge the compressed bulk material. 
   This method may also include connecting a pulsing  100  system between the vacuum source and the exit nozzles of the flat heat exchanger plates  10  to isolate the vacuum source and reconnect the vacuum source in a cyclic manner having a predetermined frequency. 
   While a preferred embodiment of the flat heat exchanger plate  10  has been described in detail, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
   Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Technology Classification (CPC): 5