Abstract:
A valve structure is provided for controlling the discharge flow from a mixing apparatus. The mixing apparatus includes a mixing bowl with a discharge opening therein. The valve includes a paddle member dimensioned to conform to and close the discharge opening in the mixing bowl. A first actuator is provides for selectively moving the paddle member between a closed position, wherein the paddle member overlaps and covers the discharge opening, and an open position, wherein the paddle member is displaced from covering the discharge opening. A second actuator mechanism is provided for selectively moving the paddle member into a sealing engagement with the bowl discharge opening, when the paddle member is in the closed position, and displaced from engagement with the bowl opening, prior to movement of paddle member to the open position by the first actuator.

Description:
FIELD OF THE INVENTION 
       [0001]    The present disclosure relates to a discharge valve for use in a mixing apparatus or a similar device. The mixing apparatus may be used for the processing of a particulate material, a liquid or slurry and may include the application of microwave energy within the process. 
       BACKGROUND 
       [0002]    It is known to use microwave energy to heat a product on a continuous or batch basis, where the product is a particulate material, a liquid or slurry. The heating may be performed fur the purpose of cooking the product, reducing the moisture content of the product or to otherwise process the product. After completion of the processing, the processed material is discharged from the processing apparatus and transported away from the apparatus for further processing or storage. 
         [0003]    US 2010/0132210 to Kruger shows an apparatus with mixing blades positioned in a horizontal bowl. A heating device is used in the process, with microwave energy being one option for supplying heat to the product. A discharge opening is provided on an end wall of the apparatus, which is closed by a pivoting flap. 
         [0004]    U.S. Pat. No. 4,882,851 to Wennerstrum et al shows a device for batch drying of a powdered or particulate product by, means of a microwave vacuum, system. The device includes a vacuum means to withdraw liquid from the process chamber. An agitator is provided in the drying chamber. Discharge of the dried particulate is accomplished by rotation of the mixing container to dump the processed material through a discharge chute or the like. 
         [0005]    U.S. Pat. No. 5,400,524 to Crosnier Leconte et al shows a device for drying a granular or powdered product having a dielectric duct with a microwave applicator therein. A rotating metal screw is positioned in the duct to convey the product. The screw includes at least one helically wound wire that extends along the duct and is spaced from the duct wall. 
         [0006]    U.S. Pat. No. 5,857,264 to Debolini shows a dryer for a powdered product having a mixer within a drying chamber. The mixer includes a series of paddle blades mounted on a shaft that is eccentrically positioned within the drying chamber. An outlet is provided in an end wall for discharge of the processed product. 
       SUMMARY OF THE INVENTION 
       [0007]    The present disclosure relates to a valve for controlling the discharge flow from a mixing apparatus or the like. The mixing apparatus includes a chamber defined by a mixing bowl and a discharge opening in the mixing bowl. The valve includes a paddle member dimensioned to close and to conform to the discharge opening in the mixing bowl. A first actuator selectively moves the paddle member between a closed position and an open position. In the closed position, the paddle member overlaps and covers the discharge opening. In the open position, the paddle member is displaced from covering the discharge opening. A second actuator mechanism is provided for selectively moving the paddle member into a sealing engagement with the bowl discharge opening, when the paddle member is in the closed position of the first actuator. The second actuator mechanism also displaces the paddle member from engagement with the bowl opening, prior to movement of paddle member to the open position by the first actuator. 
         [0008]    In a further aspect of the disclosure, a valve housing is provided that surrounds and encloses the paddle member during its movement between the open and closed positions. The housing includes a valve discharge opening that is in communication with the bowl discharge opening when the paddle member is in the open position. 
         [0009]    In a further aspect of the disclosure, means may be provided for attaching the valve housing to the mixing bowl. The valve attaching means may releasably attach the housing to the mixing bowl. Further, the valve attaching means may pivotably secure the housing to the mixing bowl. 
         [0010]    In a further aspect of the disclosure, the first and second actuators may be attached to the housing and positioned outwardly of a housing wall. The first and second actuators preferably communicate with the paddle member through the housing wall. Further, the first actuator preferably moves the paddle member linearly and transverse to the discharge opening. The second actuator preferably rotates a cam shaft having an eccentric surface thereon. The eccentric surface preferably moves the paddle member between the engaged and displaced positions with the discharge opening. The eccentric surface may be provided in the form of a tab attached to the cam shaft. The second actuator mechanism may include two actuator members, each rotating a cam member into contact with the paddle member. The two actuator members are synchronized to engage their eccentric cam surfaces against the paddle in a manner that equalizes the sealing force of the paddle against the discharge opening. 
         [0011]    In a still further aspect of the disclosure, a further actuator may be provided for assisting the second actuator in selectively moving the paddle member into a sealing engagement with the bowl discharge opening. The actuator preferably rotates a further cam shaft having an eccentric surface thereon for engaging the paddle member for moving the paddle member between the engaged and displaced positions with the discharge opening. 
         [0012]    In a further aspect of the disclosure a mixing apparatus is provided having a mixing bowl and valve structure. The mixing bowl includes a bowl wall defining a mixing chamber, and a discharge opening in the mixing bowl. The valve structure is releasably attached to the mixing bowl and covering the discharge opening. The valve structure includes a paddle member dimensioned to close the discharge opening and formed to conform to the mixing bowl adjacent the discharge opening. A valve housing is provided and surrounds and enclosing the paddle member. The housing includes a valve discharge opening in communication with the bowl discharge opening. A first actuator is provided for selectively moving the paddle member between a closed position, wherein the paddle member overlaps and covers the discharge opening, and an open position wherein the paddle member is displaced from covering the discharge opening. A second actuator mechanism is provided for selectively moving the paddle member into a sealing engagement with the bowl discharge opening. This selective movement occurs when the paddle member is in the closed position of the first actuator. The paddle member is further displaced from engagement with the bowl opening, prior to movement of paddle member to the open position by the first actuator. 
         [0013]    Other features of the present invention and combinations of features will become apparent from the detailed description to follow, taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    For the purpose of illustrating the invention, the drawings show one or more forms that are presently preferred. It should be understood that the invention is not limited to the precise arrangements and instrumentalities shown in the drawings. 
           [0015]      FIG. 1  shows an elevation view of a mixing apparatus with certain internal structures of the mixer bowl and the agitator being shown in phantom and a discharge valve provided on an underside of the mixer. 
           [0016]      FIG. 2  shows an enlarged view in cross section of a portion of the mixing apparatus and a discharge valve structure. 
           [0017]      FIG. 3  shows a top plan view of the internal structures of the discharge valve, with the valve plate shown in an open position. 
           [0018]      FIG. 4  shows a perspective view of the discharge valve with structure elements being exploded from the main valve body. 
           [0019]      FIG. 5  shows a side elevation of the discharge valve as mounted on a bottom surface of the mixer (shown in cross section), with a secondary pivoted position for the valve structure shown in phantom. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    In the figures, where like numerals identify like elements, there is shown an embodiment of a mixer or mixing apparatus generally designated by the numeral  10 . The mixer  10  includes a bowl  12  supported by legs  14 . As shown, wheels are provided on the legs, making the mixer  10  portable. The mixer  10  defines a closed mixing chamber formed by the bowl  12  and a hinged cover or lid  16 . The lid  16  closes an access opening  22  into the bowl  12 . A series of ports (not shown) may be provided for access into (and out of) the chamber defined by the bowl. A further port may be provided for the introduction of microwave energy into the chamber. The further port may be connected to a duct, which is further connected to a wave guide or generator (not shown) for supplying the microwave energy into the chamber. In addition, a material source may be introduced into the chamber via one of the provide ports. An agitator  18  (shown in phantom) is provided within the mixing chamber. The agitator  18  as shown includes a series of paddles mounted on a rotational shaft that extends the length of the bowl  12  and is driven by a motor  20  attached at one end of the mixer  10 . Other forms of agitators may be provided, including a ribbon conveyor, flat blades or other structures. 
         [0021]    The mixer  10  as shown is for batch processing of product, as compared to the continuous processing of product. The lid  16  is provided to cover an inlet opening  22 . The lid  16  pivots with respect to the bowl  12  by means of a hinge to expose the opening  22 . The bowl  12  is preferably asymmetrical in that there is a rounded bottom or base portion  24  and extended, generally rectangular top portion  26 . The agitator  18  is positioned within the base portion  24  of the bowl  12 . The agitator paddles are rotated about the shaft and are positioned closely adjacent the curved bottom of the base  24  of the bowl  12 . The direction of rotation and the rotational speed of the agitator  18  may vary for purposes of mixing and discharge from the bowl. For example, it may be advantageous for the rotation to be reversed during one or more portions of the product processing. Alternatively or in addition thereto, the agitator rotation may be stopped during a portion of the process. The product being processed within the mixer, the form of the agitator and the timing of the microwave energy are three of the potential parameters that may affect the speed and direction of the agitator. 
         [0022]    A discharge valve  30  is provided on the base  24  of the bowl  12 . The valve  30  is generally shown in  FIG. 1  and is removably attached to the underside surface of the base  24  of the mixer bowl  12 . In the cross section of  FIG. 2 , the valve is shown to include a housing  32  that engages the outside surface of the bowl  12  and is sealed thereto by a gasket  36 . The housing  32  surrounds a discharge opening  34  formed in the wall of the bowl  12 . The opening  34  communicates with the interior of the bowl  12 . The opening  34  is defined by a peripheral flange  38 . A paddle plate  40  is provided within the valve housing  32  and seals with the flange  38  to close the discharge opening  34 . As described in further detail herein, the plate  40  is movable out of engagement with the flange  38  to permit material to pass through the discharge opening  34  and out through a valve opening  42  at the base of the housing  32 . The structural elements of the valve  30  are shown in an exploded formation in  FIG. 4 . 
         [0023]    Movement of the plate  40  within the valve  30  is created by a first or linear actuator  44  and a second actuator mechanism formed by a pair of cam actuators  46 ,  48 . The linear actuator  44  moves the plate laterally between the bowl sealing position, as shown in  FIG. 2 , and the discharge position, as shown in  FIG. 3 . The cam actuators  46 ,  48  are provided for moving the plate  40  vertically into a sealing engagement with the flange  38  surrounding the bowl opening  34 . 
         [0024]    The cam actuators  46 ,  48  of the second actuator mechanism respectively rotate the cam shafts  50 ,  52  positioned within the housing  32 . Attached to the cam shafts  50 ,  52  are cam tabs  54 ,  56 . The tabs  54 ,  56  form eccentric surfaces that contact the underside of the plate when the cam shafts  50 ,  52  are rotated into position by their corresponding actuators  46 ,  48 . The actuators  46 ,  48  are positioned on the outside of the housing  32 . Linkage  58 ,  60  is respectively attached to each actuator  46 ,  48  to translate the linear movement of the actuators  46 ,  48  into rotational movement of the cam shafts  50 ,  52 . The actuators  46 ,  48  are oppositely positioned and rotate the two cam shafts  50 ,  52  in opposite directions. Rotation of the shafts  50 ,  52  move their corresponding tabs  54 ,  56  into and out of contact with the bottom of the plate  40 . The second actuator mechanism preferably synchronizes the rotating of the two cam members into contact with the paddle member. However, the amount of travel for each cam is contemplated to be independent and each may be adjusted as desired. Preferably, the two actuators engage the paddle in a manner that equalizes the sealing force of the paddle around the circumference of the discharge opening. Other forms of activation of the plate to seal with the flange and the discharge opening are possible and will be recognized upon review of the present disclosure. 
         [0025]    In  FIG. 2 , the actuators  46 ,- 48  are in their retracted position, rotating the shafts  50 ,  52  (with only shaft  52  shown after the cross section of the housing) such that the tabs  54 ,  56  (with only tab  54  shown in the cross sectional view) engage the plate  40  and move it into engagement with the flange  38  A gasket  62  may be provided on the flange  38  to enhance the sealing engagement between the plate  40  and the flange  38 . Vertical movement of the plate  40  relative to the actuator shaft  64  that extends from the linear actuator  44  is permitted by a connection adjusting means. The adjusting means is shown to be formed by a projecting hook member  66  formed on the underside of the plate  40  (shown in cross section in  FIG. 2 ) and an engagement tip  68  on the end of the shaft  64 , forming a receiving groove. The hook member  66  forms a slot in which the engagement tip is inserted. The slot permits the plate  40  to move vertically while the shaft tip  68  remains laterally engaged with the hook  66 . Other forms of engagement the permit the plate to move vertically during its sealing activation motion are possible and will be recognized upon review of the present disclosure. 
         [0026]    in  FIG. 3 , the actuators  46 ,  48  are operated to extend, rotating the shafts  50 ,  52  to remove the sealing force caused by the earn tabs  54 ,  56 . As the tabs  54 ,  56  are moved away from forcing the plate  40  into sealing engagement with the flange  38 , the linear actuator  44  is activated to retract and withdraw the plate  40  from under the flange  38 . As the plate is moved to the open position, the material within the bowl  12  of the mixer  10  may move out of the discharge opening  34 , through the valve housing  32 , and out of the valve opening  42 . A transport bin or connecting conduit (not shown) may be provided to move the discharged material to a new location from further processing. 
         [0027]    In  FIG. 5  there is shown the releasable attachment of the valve  30  to the bowl  12  of the mixer  10 . In the first or sealed position of the valve  30 A, the housing  32  is fixed to the underside of the bowl  12  and sealed by gasket  36 . The structure of attachment means is also shown in  FIG. 4 . Pivot brackets  72  attached to the bowl wall are positioned on one side of the housing  32  and connector brackets  74  are positioned on the opposing side. Release of the connection of the housing to the connector brackets permits the housing  32  to pivot about its connection to the pivot brackets  72  into the valve position  30 B. The valve may then be removed from the bowl or otherwise accessed. 
         [0028]    The pivot brackets  72  each include a pivot shaft  76  and removable pins  78  to hold the shaft in place. Projecting hooks  80  are formed on the outside of the housing  32 . The hooks  80  fit within slots formed in the body of the brackets  72  and wrap over the pins  78 . A lock may be provided to assist in fixing the position and engagement of the hooks with the brackets. 
         [0029]    The connector brackets  74  each include a shaft  82  have a hole  84  therein that aligns with a slot within the bracket body. A screw shaft  86  is inserted into the hole  84  in the shaft  82  and projects from the bracket body. Threads are provided on the end of the screw shaft and are engaged by a thumb nut  88 . A projecting tab  90  is formed on the outside of the housing  32  and includes a slot for receipt of the screw shaft  86 . The thumb nut  88  engages the tab  90  and, upon tightening, secures the housing  32  to the bowl wall. Un-tightening the thumb screws  88  permits the screw shaft to be rotated away from the tab  90  to release the housing  32  and permit pivoting of the valve to position  30 B. Other forms of securing and sealing the valve housing to the bowl around the discharge opening are possible and will be recognized upon review of the present disclosure, 
         [0030]    Various openings and flanges are shown to be formed and attached to the housing  32  of the valve  30  and their structures detailed in  FIG. 5 , among other places. A plurality of sanitary fittings  92  are provided on the sidewalls of the housing  32  and include sealing end caps  94  thereon. The end caps  94  may be selectively removed for access to the interior of the housing, including the paddle member  20 . The fittings  92  may also support a variety of sensors, clean-in-place equipment, input devices, etc. Tri-clamps  96  are shown as forming the seal for various structures, including the cam shafts  50 ,  52  and actuator  44 . 
         [0031]    The valve structure as described and shown is contemplated to be applicable to a number of apparatus and is not limited to mixing apparatus. In the presently contemplated structure, the paddle is formed as a flat plate, with the projected end of the flange being machined to form matching flat engagement surface. Preferably, the plate of the paddle and the tubular flange are formed of metal. The flange may include a machined groove therein for receipt of an o-ring (or similar) gasket to add to the sealing of the paddle to the flange. 
         [0032]    In the preferred application, the mixing apparatus may further process the contents by heating, including the use of microwave energy as part of the heating or processing of the product, A microwave or other energy source may be directed into the bowl through a flanged inlet (not shown) that surrounds a projected portion of the bowl. The fittings and sealing structures of the valve are contemplated to be formed in a way to form a microwave choke and thus deter or prevent microwave leakage from the bowl. The flat—metal-on-metal—seal arrangement between the paddle member and the flange surrounding the discharge opening is sufficient to choke or prevent microwave leakage, particularly when the product is filled in the bowl. The addition of the (o-ring) gasket is contemplated to further seal the bowl opening within applications involving liquid or slurries. The gasket may also be effective in sealing the bowl in pressurized or vacuum applications. 
         [0033]    The present disclosure includes a description and illustration of various exemplary embodiments. It should be understood by those skilled in the art from the foregoing that other changes, omissions and additions may be made, without departing from the spirit and scope of the invention, with the invention being identified by the foregoing claims.