Abstract:
A slide valve assembly is provided for selectively dispensing dry goods from a hopper. The slide valve assembly is readily attached and detached from the hopper and is readily disassembled and reassembled to facilitate cleaning and/or servicing. Preferably, the slide valve assembly includes a panel secured to spaced support rails, a movable valve panel for opening and closing of the dispensing portion of the hopper, and a collar retainer for releasable attachment to the dispensing portion of a hopper. The slide valve assembly may be attached, detached, assembled, and disassembled substantially without the use of tools or separate fasteners, to minimize the risk of creating a contamination hazard for the goods dispensed from the hopper, while still allowing for secure attachment to the hopper.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is directed to a slide valve and, more specifically, to a slide valve for use in selectively dispensing dry goods from a hopper. 
       BACKGROUND OF THE INVENTION 
       [0002]    Hoppers are frequently used for storage and dispensing of dry goods ranging from foodstuffs to chemicals, including powders and granular materials such as plastic resins, gravel, and sand, and are provided with a dispensing valve at the bottom of the hopper to control or limit the flow of the goods out of the hopper. However, typical slide valves can be difficult to remove and reinstall, which discourages operators from cleaning the valves on a regular basis. In addition, typical valves are assembled using rivets, bolts, or other mechanical fasteners that are prone to breakage or loosening during operation of the hopper and slide valve, which can lead to contamination of the dispensed dry goods with metal hardware. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention provides a slide valve that is releasably coupled to a lower or dispensing end portion of a hopper. The slide valve may be readily coupled to the hopper and decoupled from the hopper to facilitate cleaning and/or servicing of the valve. Further, the slide valve is assembled from interlocking parts so that it can be readily disassembled without tools, and to substantially limit or prevent the possibility of pieces associated with the valve (such as loose fasteners or the like) coming loose and falling into the dry bulk goods that are dispensed from the hopper. 
         [0004]    According to one form of the present invention, a slide valve for selectively dispensing dry bulk goods from a hopper includes at least one panel, a pair of spaced support rails, a movable valve panel, and a collar retainer. The at least one panel has opposite side portions to which the support rails releasably attach. The collar retainer is positioned adjacent the at least one panel and defines an opening for receiving a dispensing portion of a hopper, so that the collar retainer can releasably attach to the dispensing portion of the hopper. The movable valve panel is positioned between the support rails and is movable between an open position and a closed position. In the movable valve panel&#39;s open position, the dispensing portion of the hopper is at least partially unblocked by the movable valve panel, and in the movable valve panel&#39;s closed position, the dispensing portion of the hopper is substantially blocked by the movable valve panel. 
         [0005]    In one aspect, the collar retainer is made up of a pair of substantially similar collar retainer halves, each of which defines approximately one-half of the opening of the collar retainer. The collar retainer halves are separable from one another to disengage the dispensing portion of the hopper. 
         [0006]    In another aspect, the at least one panel includes at least one non-removable retaining element along each of the opposite side portions. Each of the support rails comprises at least one mounting element for securely and releasably engaging the non-removable retaining elements of the panel. 
         [0007]    In yet another aspect, the at least one panel includes at least one resilient locking projection configured to releasably and lockably engage at least one of the support rails at the at least one mounting element. 
         [0008]    In still another aspect, the at least one non-removable retaining element is a plurality of L-shaped projections along each side portion of the panel, and the at least one mounting element of the support rails is at least one row of apertures along each of the support rails. The apertures are configured to receive the L-shaped projections. Optionally, the L-shaped projections are unitarily formed with the at least one panel. 
         [0009]    In a further aspect, the at least one panel includes an upper panel disposed above the movable valve panel, plus a lower panel disposed below the movable valve panel. 
         [0010]    In another aspect, each of the support rails includes an upper channel and a lower channel, each for receiving a respective one of the opposite side portions of the upper panel and the lower panel, and each including a row of apertures for receiving the L-shaped projections of the upper panel and the lower panel. 
         [0011]    Optionally, each of the support rails includes a middle flange between the upper channel and the lower channel, the middle flange for slidably engaging opposite side portions of the movable valve panel. 
         [0012]    In a still further aspect, the slide valve includes a conduit that is removably positioned in an opening of the lower panel, the conduit in fluid communication with an opening of the upper panel and the dispensing portion of the hopper when the movable valve panel is in the open configuration. Optionally, the conduit is only removable from the lower panel when the upper panel has been removed from between the support rails and when the slide valve is detached from the hopper. 
         [0013]    In still another aspect, the slide valve is combined with a hopper configured to store and dispense dry bulk goods. 
         [0014]    According to another form of the present invention, a slide valve for selectively dispensing dry bulk goods from a hopper includes an upper panel, a lower panel spaced below the upper panel, a movable valve panel positioned between the upper panel and the lower panel, a collar retainer, and a pair of spaced support rails. The upper panel defines an opening and the lower panel defines an opening that is aligned with the opening of the upper panel. The collar retainer is positioned above the upper panel and defining an opening for receiving a dispensing portion of a hopper, the collar retainer configured to releasably attach to the dispensing portion of the hopper. Each of the support rails receives a respective opposite side portion of the upper panel and the lower panel. The movable valve panel is positionable between a closed position in which the openings of the upper and lower panels are substantially blocked, and an open configuration in which the openings of the upper and lower panels are at least partially unblocked. 
         [0015]    In various aspect similar to those described above, the collar retainer may include a pair of substantially similar collar retainer halves, which optionally may include at least one resilient locking projection for releasably and lockably engaging at least one of the support rails. The upper panel and the lower panel may each include at least one non-removable retaining element, such as a plurality of L-shaped projections, along each opposite side portion thereof, while each of the support rails may include at least one mounting element, such as one or more apertures, for securely and releasably engaging the at least one non-removable retaining element along each opposite side portion of the upper panel and the lower panel. The upper panel and the lower panel may each further include at least one resilient locking projection for releasably and lockably engaging at least one of the support rails. 
         [0016]    Optionally, each of the support rails defines an upper channel and a lower channel, each for receiving one of the opposite side portions of the upper panel and the lower panel, respectively. Each of the support rails may further include a middle flange, between the upper channel and the lower channel, for slidably engaging opposite side portions of the movable valve panel. 
         [0017]    Optionally, the slide valve may include a conduit that is removably positioned in the opening of the lower panel. The conduit is in fluid communication with the opening of the upper panel and the dispensing portion of the hopper when the movable valve panel is in the open configuration. The conduit may be positioned so that is only removable from the lower panel when the upper panel has been removed from between the support rails and when the slide valve is detached from the hopper. 
         [0018]    According to another form of the present invention, a method is provided for removing a slide valve from a hopper. The method includes providing a hopper with a dispensing portion, and providing a slide valve including an upper panel and a movable slide panel below the upper panel. Each of the panels is supported between a pair of support rails. A two-piece collar retainer is coupled between the support rails and disposed above the upper panel, the two-piece collar defining an opening for coupling to the dispensing portion of the hopper. A first piece of the two-piece collar is de-coupled from the support rails and from the dispensing portion of the hopper. The upper panel, the slide panel, and the support rails are then de-coupled from the dispensing portion of the hopper. Optionally, the upper panel, the slide panel, and the support rails may be de-coupled from the dispensing portion of the hopper, together as a unit. A second piece of the two-piece collar may optionally be de-coupled from the support rails prior to de-coupling the upper panel, the slide panel, and the support rails from the hopper. 
         [0019]    Accordingly, the slide valve of the present invention provides a valve that is readily detached from a hopper, disassembled, reassembled, and reattached to a hopper to facilitate cleaning or servicing of the valve. The slide valve reduces or eliminates the risk of contaminating dry goods that are dispensed through the slide valve with loose pieces from the valve, and facilitates a method by which the slide valve is readily removed from a hopper and disassembled. 
         [0020]    These and other objects, advantages, purposes and features of the invention will become more apparent upon review of the following specification in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a perspective view of a slide valve assembly in accordance with the present invention, positioned at a lower end portion of a hopper; 
           [0022]      FIG. 2  is an exploded perspective view of the slide valve assembly of  FIG. 1 ; 
           [0023]      FIG. 3  is a top plan view of the slide valve assembly of  FIG. 1 ; 
           [0024]      FIG. 4  is a side elevation of the slide valve assembly of FIG,  1 ; 
           [0025]      FIG. 5  is a sectional view of the slide valve assembly taken along section line V-V of  FIG. 4 ; 
           [0026]      FIG. 6  is a sectional view of the slide valve assembly taken along section line VI-VI of  FIG. 4 ; 
           [0027]      FIG. 7  is a sectional view of the slide valve assembly taken along section line VII-VII of  FIG. 4 ; 
           [0028]      FIG. 8  is another top plan view of the slide valve assembly; 
           [0029]      FIG. 9  is a section view of the slide valve assembly taken along section line IX-IX of  FIG. 8 ; 
           [0030]      FIG. 10  is an enlarged view of the area designated X in  FIG. 9 ; 
           [0031]      FIG. 11  is a perspective view of a lower panel of the slide valve assembly; 
           [0032]      FIG. 12  is a top plan view of an upper panel of the slide valve assembly; 
           [0033]      FIG. 13  is a bottom perspective view of a movable valve panel of the slide valve assembly; 
           [0034]      FIG. 14  is a top plan view of a collar retainer half of the slide valve assembly; 
           [0035]      FIG. 15  is a bottom perspective view of a conduit of the slide valve assembly; 
           [0036]      FIG. 16  is a side elevation of the conduit of  FIG. 15 ; 
           [0037]      FIG. 17  is a perspective view of a support rail of the slide valve assembly, with portions shown in phantom; 
           [0038]      FIG. 18  is a perspective view of another support rail of the slide valve assembly; 
           [0039]      FIG. 19  is a perspective view of a dust seal of the slide valve assembly; and 
           [0040]      FIGS. 20A-I  are perspective views of the slide valve assembly, depicting sequential steps of detaching the slide valve assembly from the dispensing portion of a hopper and disassembling the slide valve assembly until all of its components are separated from one another. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0041]    Referring now to the drawings and the illustrative embodiments depicted therein, a slide valve assembly  10  is installed at a hopper&#39;s lower dispensing portion  12  ( FIG. 1 ). Slide valve assembly  10  includes an upper panel  14 , a lower panel  16 , and a movable valve panel  18 , each supported between a pair of side or support rails  20   a,    20   b  ( FIGS. 1 and 2 ). Also supported between support rails  20   a,    20   b  is a collar retainer made up of two collar retainer halves  22   a,    22   b,  which are positioned above the upper panel  14  and which hold the slide valve assembly  10  to the lower end portion of the hopper  12 , as will be described below. In the illustrated embodiment, an optional conduit  21  and dust seal  23  ( FIG. 2 ) complete the slide valve assembly  10 . Movable valve panel  18  is positionable between an open and extended position ( FIGS. 1 ,  3 ,  4 ,  6 - 9 , and  20 A) and a closed and retracted position to selectively dispense dry goods out of hopper lower end portion  12  and through slide valve assembly  10 . It will be appreciated that slide valve assembly  10  is made up of self-engaging components that may be readily disassembled from hopper lower end portion  12  and one another, and reassembled to each other and hopper lower end portion  12 , all without using separate mechanical fasteners that could pose a contamination risk to the dispensed goods. 
         [0042]    Upper panel  14  is generally rectangular in shape, including opposite side portions  14   a,    14   b,  a distal end portion  14   c,  and a proximal end portion  14   d  ( FIG. 12 ). Upper panel  14  is substantially planar and defines a circular opening  24  that is spaced evenly between side portions  14   a,    14   b,  and that is positioned nearer to distal end portion  14   c.  A plurality of non-removable retaining elements, preferably in the form of L-shaped projections  26  that are integral and unitarily formed in one piece with side portions  14   a,    14   b,  so as to extend from each of the side portions  14   a,    14   b  of upper panel  14 . L-shaped projections  26  extend outwardly away from the respective side portions  14   a,    14   b  of the panel, and are shaped to lockably but releasably engage support rails  20   a,    20   b,  as will be described below. Proximal end portion  14   d  defines a recess  28  that provides clearance for an operator&#39;s hand when operating movable valve panel  18 . 
         [0043]    Resilient locking projections  30   a,    30   b  extend or project from respective opposite side portions  14   a,    14   b  of the upper panel, in the vicinity of proximal end portion  14   d  ( FIG. 12 ). Each locking projection  30   a,    30   b  has, at its free end, an engaging portion  32   a,    32   b  that releasably and lockably engages a respective support rail  20   a,    20   b.  Engaging portions  30   a,    30   b  each include a respective stop surface  31   a,    31   b  that is substantially perpendicular to opposite side portions  14   a,    14   b,  and a ramped surface  33   a,    33   b  that is angled relative to opposite side portions  14   a,    14   b  and proximal end portion  14   d.  Stop surfaces  31   a,    31   b  are configured to contact portions of support rails  20   a,    20   b  to limit or prevent movement of upper panel  14  in the direction faced by the stop surfaces. Ramped surfaces  33   a,    33   b  allow upper panel  14  to be moved along the support rails in the opposite direction (i.e. in the direction of distal end portion  14   c ) during assembly of the slide valve by allowing locking projections  30   a,    30   b  to deflect inwardly. 
         [0044]    Lower panel  16  is substantially similar to upper panel  14 , and includes opposite side portions  16   a,    16   b,  a distal end portion  16   c,  and a proximal end portion  16   d  ( FIG. 11 ). Lower panel  16  further defines a circular opening  34  that aligns with hopper lower end portion  12 , a plurality of preferably L-shaped projections  36 , a recess  28  at the proximal end portion  16   d,  and a pair of resilient locking projections  40   a,    40   b  with engaging portions  42   a,    42   b  having respective stop surfaces  41   a,    41   b  and ramped surfaces  43   a,    43   b.  Projections  36  are preferably integral and unitarily formed in one piece with lower panel  16  at side portions  16   a,    16   b.  Opening  34  in lower panel  16  is substantially aligned with the opening  24  in upper panel  14  when slide valve assembly is fully assembled with upper panel  14  positioned directly above lower panel  16 . Opening  34  is generally circular and includes a pair of notches  44   a,    44   b  positioned across from one another. In addition, lower panel  16  defines a generally circular shelf portion  46  around the perimeter of opening  34 , where the thickness of lower panel  16  is reduced. Notches  44   a,    44   b  and circular shelf portion  46  facilitate supporting conduit  21 , as will be described below. 
         [0045]    Movable valve panel  18  is rectangular in shape and generally corresponds to the size and shape of upper panel  14  and lower panel  16 , although valve panel  18  may be at least somewhat narrower in width, and without L-shaped projections, to provide adequate clearance between support rails  20   a,    20   b  ( FIG. 13 ). Much like upper panel  14  and lower panel  16 , movable valve panel  18  includes opposite side portions  18   a,    18   b,  a distal end portion  18   c,  and a proximal end portion  18   d.  Each of the opposite side portions  18   a,    18   b  includes a single projection  48   a,    48   b  extending outwardly in the plane of panel  18  for limiting the extent of travel of the movable valve panel  18  along the support rails  20   a,    20   b,  as will be described below. Located at proximal end portion  18   d  is an opening  50  that provides a handle for grasping by an operator. The operator can grasp the movable valve panel  18  at the opening  50  and manually move the panel between an open position and a closed position by applying a pull or push force to the panel, respectively. In the illustrated embodiment, movable valve panel  18  includes a plurality of parallel grooves  52  in its lower surface, which grooves serve to reduce the friction of panel  18  as it slides along lower panel  16 , on which movable valve panel  18  is supported. It will be appreciated that the movable valve panel could be actuated between opened and closed positions by a powered actuator, if desired, such as a pneumatic, hydraulic, or electric actuator, which could be controlled from a remote location. 
         [0046]    In the illustrated embodiment, the collar retainer that couples slide valve assembly  10  to hopper lower end portion  12  includes of a pair of collar retainer halves  22   a,    22   b  that are substantially identical to one another ( FIGS. 5 and 14 ). Each collar retainer half  22   a,    22   b  includes a half-circular recess  54 , a pair of resilient locking projections  56   a,    56   b  with respective engaging portions  58   a,    58   b,  and an arcuate section of reduced thickness  60  that surrounds half circular recess  54  ( FIG. 14 ). Arcuate section  60  is dimensioned to receive one-half of a generally circular flange  64  ( FIGS. 2 and 9 ) at the lower end portion of the hopper  12 , to fixedly attach slide valve assembly  10  to the lower end portion of the hopper, such as best shown in  FIGS. 1 ,  2 ,  9 , and  10 . Thus, collar retainer halves  22   a,    22   b  cooperate to fully encircle and entrap the flange  64  of the hopper lower end portion  12 , which holds slide valve assembly  10  fixed (except for movable valve panel  18 ) relative to hopper lower end portion  12 . Each collar retainer half  22   a,    22   b  includes a pair of distal end faces  62   a,    62   b  that lie in close proximity to (or in abutment with) the corresponding distal end faces of the other collar retainer half  22   b,    22   a  when slide valve assembly  10  is assembled, such as shown in  FIG. 5 . 
         [0047]    Collar retainer halves  22   a,    22   b  have substantially the same width as upper and lower panels  14 ,  16  (excluding L-shaped projections  26 ,  36 ), so that the collar retainer halves may be placed and retained between support rails  20   a,    20   b.  Collar retainer halves  22   a,    22   b  include resilient locking projections  56   a,    56   b  that are configured to lockably but releasably engage respective ones of the support rails  20   a,    20   b,  much like the resilient locking projections  40   a,    40   b  and  30   a,    30   b  of upper and lower panels  14 ,  16 . Resilient locking projections  56   a,    56   b  are flexible so that engaging portions  58   a,    58   b  may be selectively disengaged from the support rails  20   a,    20   b,  which allows one or both of collar retainer halves  22   a,    22   b  to be removed from support rails  201 ,  20   b  such that support rails  20   a,    20   b  may be removed or locked in place for detaching or attaching slide valve assembly  10  from the hopper lower end portion of hopper  12 , or for allowing further disassembly of the slide valve assembly. 
         [0048]    Conduit  21  is generally tubular in shape, with an upper flange  66  ( FIGS. 6 ,  10 ,  15 , and  16 ) that is supported at circular shelf portion  46  of lower panel  16 . In addition, conduit  21  includes a pair of radial and partially-circumferential projections  68  spaced slightly below upper flange  66  ( FIGS. 15 and 16 ), which are received in the notches  44   a,    44   b  surrounding the opening  34  of lower panel  14  ( FIG. 11 ). Projections  68  may be used to lock conduit  21  to lower panel  16 , such as by rotating the conduit  21  relative to lower panel  16  so that circular shelf portion  46  is received in the space between projections  68  and upper flange  66 . Optionally, projection  68  may simply rest in the respective notches  44   a,    44   b  to limit or prevent rotation of conduit  21  relative to lower panel  16 . In the illustrated embodiment, the lower tubular portion of conduit  21  is slightly funnel-shaped, having a narrower outlet than inlet, which facilitates the attachment of a container such as a bag, or which can be used to direct the flow of goods out of the hopper lower end portion  12 . 
         [0049]    Support rails  20   a,    20   b  are substantially identical and formed in a mirror image of one another, such as shown in  FIGS. 17 and 18 . Each support rail  20   a,    20   b  includes an upper longitudinal channel  70  for receiving upper panel  14  and collar retainer halves  22   a,    22   b,  and a lower longitudinal channel  72  for receiving lower panel  16 , which in turn supports conduit  21 . Thus, each of the support rails  20   a,    20   b  is generally E-shaped in cross section, with upper longitudinal channel  70  defined between an upper flange  74  and a middle flange  76 , and with lower longitudinal channel  72  defined between middle flange  76  and a lower flange  78 , all of which face inwardly when support rails  20   a,    20   b  are assembled with slide valve assembly  10 . 
         [0050]    The middle flanges  76  of support rails  20   a,    20   b  each include an elongate notch  80 , defined between a middle or distal end  80   a  and an opposite or proximal end  80   b,  the notch  80  extending along approximately one-half of the length of the middle flange  76 . Thus, the elongate notches  80  are arranged generally toward the end of each support rail  20   a,    20   b  that is away from conduit  21 , and in the direction of handle  50  of movable valve panel  18  ( FIGS. 16 ,  17 , and  18 ). Elongate notches  80  receive the respective projections  48   a,    48   b  of movable valve panel  18 , and serve to limit the travel of movable valve panel  18  along support rails  20   a,    20   b.  Thus, when movable valve panel  18  is pushed in fully to its closed position, projections  48   a,    48   b  contact the middle or distal ends  80   a  defining elongate notch  80 , and when the movable valve panel  18  is moved out to its fully open position, projections  48   a,    48   b  contact the opposite or proximal end  80   b  of elongate notch  80 . However, it will be appreciated that notches  80  and projections  48   a,    48   b  could be positioned elsewhere and/or made with different dimensions, such as to change the travel limits of movable valve panel  18 . 
         [0051]    Each support rail  20   a,    20   b  includes a plurality of mounting elements in the form of an upper row of apertures  82  along upper longitudinal channel  70  and a lower row of apertures  84  along lower longitudinal channel  72  (FIGS,  1 ,  2 ,  4 , and  7 ). Upper apertures  82  are spaced corresponding to the spacing of L-shaped projections  26  of upper panel  14 , while lower apertures  84  are spaced corresponding to the L-shaped projections  36  of lower panel  16 . Thus, upper apertures  82  configured to receive L-shaped projections  26  and lower apertures  84  are configured to receive L-shaped projections  36  during assembly of the slide valve assembly, such as shown in  FIGS. 1 and 7 . 
         [0052]    In addition, each support rail  20   a,    20   b  includes a pair of spaced upper openings  86   a,    86   b  ( FIGS. 1 and 2 ) for receiving the respective engaging portions  58   a,    58   b  of the resilient locking projections  56   a,    56   b  of collar retainer halves,  22   a,    22   b,  such as shown in  FIG. 5 . Spaced upper openings  86   a,    86   b  permit collar retainer halves  22   a,    22   b  to be retained securely between support rails  20   a,    20   b  unless and until resilient locking projections  56   a,    56   b  are manually deflected to disengage the engaging portions  58   a,    58   b  from spaced upper openings  86   a,    86   b  of support rails  20   a,    20   b.  Located at a proximal end of each support rail  20   a,    20   b  is a panel lock opening or aperture  88  for receiving the engaging portions  32   a,    32   b  and  42   a,    42   b  of resilient locking projections  30   a,    30   b  and  40   a,    40   b  of upper panel  14  and lower panel  16 , respectively. Thus, the engagement of engaging portions  32   a,    32   b  and  42   a,    42   b  with panel lock openings  88  in support rails  20   a,    20   b  prevents the upper panel  14  and lower panel  16  from disengaging their respective L-shaped projections  36  from the respective upper apertures  82  and lower apertures  84 , so that support rails  20   a,    20   b  cannot be separated from upper panel  14  and lower panel  16  unless resilient locking projections  30   a,    30   b  and  40   a,    40   b  are first manually deflected inwardly to disengage the engaging portions  32   a,    32   b  and  42   a,    42   b  from panel lock openings  88  ( FIGS. 1 and 7 ). 
         [0053]    The main components of slide valve assembly  10 , including upper panel  14 , lower panel  16 , movable valve panel  18 , support rails  20   a,    20   b,  collar retainer halves  22   a,    22   b,  and conduit  21  may be made from metal or resinous material, or any other material that is sufficiently strong and rigid, and moisture or corrosion resistant, depending on the goods dispensed through the valve assembly, the operating environment, etc. For example, stainless steel approved for food contact may be used for dispensing grains or other foodstuffs, or resinous materials such as plastics or reinforced plastics may be used. 
         [0054]    Optionally, and with reference to  FIGS. 10 and 19 , dust seal  23  may be provided above movable valve panel  18  to clean the top surface of the distal end portion  18   c  of the valve panel as the valve panel moves relative to dust seal  23  from the valve panel&#39;s open position to its closed position. Dust seal  23  also substantially seals or blocks the gap between upper panel  14  and lower panel  14  when movable valve panel  18  is in an open position, such as shown in  FIG. 10 , to limit or prevent the venting of dust from slide valve assembly  10  when dry goods are being dispensed through the valve. Dust seal  23  includes a mounting portion  90  and a generally planar flexible wiping portion  92  ( FIG. 19 ). Mounting portion  90  is received in a correspondingly-shaped channel  94  at the lower surface of upper panel  14  ( FIG. 10 ). Dust seal  23  may be made from essentially any sufficiently strong and resilient material, such as natural or synthetic rubber or the like, and provides the function of a squeegee or wiper as it traverses the upper surface of movable valve panel  18 . 
         [0055]    Accordingly, the present invention provides a slide valve for dispensing dry bulk goods from a hopper, the slide valve assembly made from mutually-engaging components, and preferably without the use of separate fasteners, so that the slide valve assembly can be readily removed from the hopper for cleaning, and can be readily disassembled and reassembled without the use of special tools. By avoiding the use of separate mechanical fasteners, the risk of any part of the slide valve assembly falling off and contaminating the goods is minimized. 
         [0056]    In addition, and with reference to  FIGS. 20A-I , a method is provided for separating the slide valve assembly  10  from the hopper lower end portion  12 , and for subsequently fully disassembling the slide valve assembly. Initially, slide valve assembly  10  may be fully assembled and attached to hopper lower end portion  12 , such as shown in  FIG. 1 . To begin the process of separating slide valve assembly  10  from hopper lower end portion  12 , engaging portions  58   a,    58   b  of collar retainer half  22   a  are depressed inwardly against the biasing force of resilient locking projections  56   a,    56   b  so that the engaging portions  58   a,    58   b  (and, particularly, stop surfaces  51   a,    51   b ) no longer engage the upper openings  86   a,    86   b  of support rails  20   a,    20   b  This permits removal of collar retainer half  22   a  by sliding it outwardly away from the hopper lower end portion  12  as shown in  FIG. 20A . 
         [0057]    Once collar retainer half  22   a  has been removed, the slide valve assembly is no longer locked onto the hopper lower end portion  12 , so that the remainder of the slide valve assembly may be moved or slid away from hopper lower end portion  12 , such as shown in  FIG. 20B . Alternatively, collar retainer half  22   b  could be slid or moved out of engagement with hopper lower end portion  12  in substantially the same manner as described above for the removal of collar retainer half  22   a,  either before or after (or simultaneously with) the removal of collar retainer  22   a,  such as to facilitate the removal of slide valve assembly  10  in a lateral direction opposite to that shown in  FIG. 20B . Optionally, slide valve assembly  10  could be removed downwardly away from hopper lower end portion  12  by first removing both collar retainer halves  22   a,    22   b.    
         [0058]    Once slide valve assembly  10  has been separated from hopper lower end portion  12 , the remainder of the slide valve assembly may be fully disassembled, beginning with the removal of collar retainer half  22   b  ( FIG. 20C ), if it has not been removed previously. Once both collar retainer halves  22   a,    22   b  have been removed, support rails  20   a,    20   b  are removed either simultaneously or one at a time, such as shown in  FIGS. 20   d  and  20   e . As discussed above, support rails  20   a,    20   b  are held in fixed positions along upper panel  14  and lower panel  16  via locking engagement of L-shaped projections  26 ,  36  with upper apertures  82  and lower apertures  84 . Movement of support rails  20   a,    20   b  relative to upper panel  14  and lower pane  16  is normally precluded by the engagement of engaging portions  32   a,    32   b  and  42   a,    42   b  of resilient locking projections  30   a,    30   b  and  40   a,    40   b  with the panel lock opening or aperture  88  of each support rail  20   a,    20   b.  Thus, to separate the support rail  20   a,    20   b  from upper panel  14  and lower panel  16 , the engaging portions  32   a,    32   b  and  42   a,    42   b  are manually depressed inwardly until they disengage panel lock opening  88 , so that support rails  20   a,    20   b  may be initially slid along the side portions of upper panel  14  and lower panel  16  and then pulled away from the panels (as shown by jogged arrows in  FIGS. 20D and 20E ) to disengage L-shaped projections  26 ,  36  from upper apertures  82  and lower apertures  84 . 
         [0059]    Once support rails  20   a,    20   b  are removed from the upper and lower panels, the upper panel  14 , lower panel  16 , and movable panel  18  may be separated from one another as shown in  FIGS. 20F and 20G . Once the upper flange  66  of conduit  21  is no longer blocked by distal end portion  18   c  of movable valve panel  18  (compare  FIG. 200  to  FIG. 20F ), conduit  21  may be removed from lower panel  16  by lifting the conduit  21  as shown in  FIG. 20H . Optionally, such as if conduit  21  is locked to lower panel  16  via engagement of projections  68  with circular shelf portion  46  of lower panel  16 , the conduit  21  is initially rotated until projections  68  align with notches  44   a,    44   b,  before lifting conduit  21  upwardly out of opening  34  and away from lower panel  16 . Once distal end portion  14   c  of upper panel  14  is exposed via separation of support rails  20   a,    20   b,  dust seal  23  may be slid laterally outwardly away from the upper panel  14 , such as shown in  FIG. 20I . Thus, the slide valve assembly can be removed from the hopper lower end portion and disassembled without the use of tools, and without the use of separate mechanical fasteners. It will be appreciated that, although the disassembly method or procedure is primarily described as not requiring the use of tools, a screwdriver or other small tool could be used to aid in depressing the engaging portions to move them out of engagement with the support rails 
         [0060]    Slide valve assembly  10  may be reassembled and reattached to hopper lower end portion  12  in substantially the reverse order of removal and disassembly, described above. However, rather than depressing engaging portions of respective resilient locking projections of the upper panel  14 , lower panel  16 , and collar retainer halves,  22   a,    22   b,  the ramped surfaces of the engaging portions allow the upper panel  14 , lower panel  16  and collar retainer halves  22   a,    22   b  to “snap” into engagement with respective openings or apertures in the support rails  20   a,    20   b,  without need to manually depress the engaging portions of the resilient locking projections of these components. Thus, the slide valve assembly can be snapped together without the use of tools, and without the use of separate mechanical fasteners. 
         [0061]    It will be appreciated that although the terms “upper” and “lower” are used throughout the specification, these terms are merely used to indicate relative positioning of various components as shown in the drawings. For example, it is envisioned that the hopper could have a dispensing portion along a side, such as for auger-driven dispensing of product, with the slide valve assembly mounted substantially perpendicularly to the orientation shown in the drawings, without departing from the spirit and scope of the present invention. It is further envisioned that the slide valve assembly could be readily adapted for dispensing fluids from a hopper or pipe, such as by adjusting tolerances and/or adding seals as appropriate to create fluid-tight connections to the hopper or pipe dispensing portion, and within the slide valve assembly itself. 
         [0062]    Accordingly, the present invention provides a slide valve assembly that is readily assembled and disassembled, without the use of special tools, and which does not include separate fasteners that could be prone to detachment or loosening and risk falling into the goods that are dispensed through the slide valve assembly. 
         [0063]    Changes and modifications in the specifically described embodiments can be carried out without departing from the principles of the present invention which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law, including the doctrine of equivalents.