Abstract:
Methods for storing and moving adhesive particulate to an adhesive melter are disclosed. An interior space of a supply hopper is filled with adhesive particulate. A transfer pump is actuated to generate a vacuum at an inlet of the transfer pump to actuate removal of the adhesive particulate from the supply hopper. A consistent minimized depth of the adhesive particulate located directly above the inlet is maintained with a shroud located within the interior space of the supply hopper. In addition, adhesive particulate can be received in an interior space of a container. An open space is maintained within the interior space of the container proximate the pump inlet, where the open space entrains gas to be drawn by the transfer pump. The transfer pump can be actuated to generate a vacuum at the pump inlet to cause removal of the adhesive particulate from the container.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a divisional application of U.S. patent application Ser. No. 14/436,663, filed Apr. 17, 2015, and published as U.S. Patent App. Pub. No. 2016/0001988 on Jan. 7, 2016, which is a U.S. national stage application of International Patent App. No. PCT/US2014/031648, filed Mar. 25, 2014, and published as International Patent App. Pub. No. WO 2014/160667 on Oct. 2, 2014, which claims the benefit of U.S. Provisional Patent App. No. 61/806,205, filed Mar. 28, 2013, the disclosures of which are incorporated by reference herein. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates generally to an adhesive bin for an adhesive melter, and more particularly, to an adhesive bin and method for moving adhesive particulate with improved pumping efficiency to an adhesive melter. 
       BACKGROUND 
       [0003]    Thermoplastic adhesives, otherwise known as “hot melt” adhesives, have been widely used in industry for various applications. For example, thermoplastic hot melt adhesives are used for carton sealing, case sealing, tray forming, pallet stabilization, nonwoven application including diaper manufacturing, and many other applications. Hot melt adhesive, in its pre-melted state (referred to herein as “particulate” hot melt adhesive), can be provided in a variety of particulate shapes and sizes, ranging from small bb-sized pieces, to larger sized pieces including pellets and chips. Adhesive material, in the form of adhesive particulate, may be supplied to the adhesive melter where it is heated and melted to a desired temperature for dispensing. Hot melt adhesives are often dispensed by systems including a dispensing gun coupled via heated hoses to an adhesive melter. 
         [0004]    An adhesive bin may contain adhesive particulate for storage prior to melting in the adhesive melter. A transfer pump, such as a pneumatic pump, connects to the adhesive bin for moving the adhesive particulate via a hose from the adhesive bin to the adhesive melter. Pneumatic pumps generally rely on the suction of gas, such as air, entrained within gaps between individual pieces of adhesive particulate stored within the adhesive bin for moving the adhesive particulate. This gas may also be referred to as “make-up” gas. Traditionally, the adhesive particulate gravity feeds into a lower portion of the adhesive bin toward an inlet of the transfer pump and submerges a majority of the pump inlet. The transfer pump generates a vacuum at the inlet that withdraws the entrained make-up gas and adhesive particulate therein. In turn, the suction of the entrained make-up gas creates a vacuum within the gaps of the adhesive particulate that withdraws additional gas from a surrounding environment. The additional gas from the surrounding environment continuously replaces the entrained/make-up gas within the adhesive bin for moving the adhesive particulate with the transfer pump. 
         [0005]    Larger sizes of adhesive particulate tend to form larger gaps of entrained make-up gas, while smaller sizes of adhesive particulate tend to form smaller gaps of entrained make-up gas. In this respect, the smaller sizes of adhesive particulate may more densely pack within the adhesive bin than the larger sizes of adhesive particulate. The increased density results in smaller gaps throughout the adhesive particulate for drawing entrained make-up gas from the surrounding environment. Additionally, it has been determined that if a vertical depth of the adhesive particulate above the inlet is increased, then the transfer pump expends additional energy withdrawing make-up gas through the adhesive particulate within the adhesive bin. Thus, increases in the vertical depth of densely packed adhesive particulate above the inlet reduce the efficiency of the transfer pump. 
         [0006]    There is a need, therefore, for an adhesive bin and method for use with a transfer pump that addresses present challenges and characteristics such as those discussed above. 
       SUMMARY 
       [0007]    An exemplary embodiment of an adhesive bin for storing and moving adhesive particulate includes a supply hopper, a transfer pump, and shroud. The supply hopper includes a sidewall and defines an interior space. The interior space is configured for storing adhesive particulate. The transfer pump includes a pump housing that defines an inlet. The transfer pump is operatively connected to the supply hopper such that the pump housing extends into the interior space of the supply hopper. The transfer pump is also operable to generate a vacuum at the inlet to actuate removal of the adhesive particulate from the supply hopper. In addition, the shroud is connected to the sidewall and extends into the interior space of the supply hopper. The shroud surrounds at least a portion of the inlet for maintaining a consistent minimized depth of the adhesive particulate located directly above the inlet within the supply hopper. 
         [0008]    In one aspect, the shroud includes a plurality of connected panels. For example, the connected panels may partially or completely surround the pump housing around the inlet. In another aspect, the shroud extends from the sidewall around the pump housing such that the shroud, pump housing, and sidewall collectively define a gas space positioned within the interior space of the supply hopper. The gas space may entrain an additional amount of make-up gas proximate to the inlet when the interior space is filled with adhesive particulate. As a result of the consistent minimized depth of the adhesive particulate and the additional make-up gas proximate to the inlet, the transfer pump operates more efficiently in moving adhesive particulate to an adhesive melter because make-up gas is easier to draw into the pump inlet with the consistent minimized depth and the active addition of more gas located proximate to the pump inlet. 
         [0009]    In another embodiment, an adhesive bin for storing and moving adhesive particulate includes a supply hopper, a transfer pump, a vibrator, and a gas conduit. The supply hopper includes a sidewall and defines an interior space. The interior space is configured for storing adhesive particulate. The transfer pump includes a pump housing that defines an inlet. The transfer pump is operatively connected to the supply hopper such that the pump housing extends into the interior space of the supply hopper. The transfer pump is also operable to generate a vacuum at the inlet to actuate removal of the adhesive particulate from the supply hopper. Additionally, the vibrator is configured to fluidly connect to a gas supply for actuating the vibrator, which is fluidly connected to the gas conduit. The gas conduit defines a gas outlet for receiving the gas supply from the vibrator. The gas outlet is positioned proximate to the inlet for exhausting the gas supply as make-up gas located around the adhesive particulate proximate to the inlet. 
         [0010]    In use, a method of moving adhesive particulate to an adhesive melter includes filling an interior space of a supply hopper with an adhesive particulate. The method further includes entraining an amount of make-up gas within a gas space at least partially defined by a shroud within the interior space of the supply hopper. As such, the gas space is proximate to an inlet of a transfer pump to thereby increase an amount of make-up gas located around the adhesive particulate proximate to the inlet. Additionally, the method includes actuating the transfer pump to generate a vacuum at the inlet to actuate removal of the adhesive particulate from the supply hopper. 
         [0011]    Various additional features and advantages of the invention will become more apparent to those of ordinary skill in the art upon review of the following detailed description of the illustrative embodiments taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention. 
           [0013]      FIG. 1  is a front perspective view of an adhesive bin used to supply adhesive particulate to an adhesive melter of an adhesive dispensing system. 
           [0014]      FIG. 2  is an enlarged rear perspective view of the adhesive bin of  FIG. 1 , showing details of a supply hopper, a transfer pump, and a vibrator. 
           [0015]      FIG. 3  is a perspective sectional view of the adhesive bin of  FIG. 1  taken along section line  3 - 3  in  FIG. 1 . 
           [0016]      FIG. 4  is a cross-sectional view of the adhesive bin of  FIG. 1  taken along section line  4 - 4  in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    With reference to  FIGS. 1-4 , an exemplary embodiment of an adhesive bin  10  configured to store and move adhesive particulate, such as pellets and chips, to an adhesive melter  12  of an adhesive dispensing system is shown. The adhesive particulate may then be melted into liquid adhesive with the adhesive melter  12  and dispensed via an adhesive dispensing module  13 . According to the exemplary embodiment, the adhesive particulate is in the form of adhesive pellets  14  (see  FIG. 4 ). As used herein, the term “adhesive pellets” is not intended to be limiting as to any specific shape or size, so long as the adhesive pellets are suitable to be carried by a stream of forced air such as a vacuum-driven stream. For example, and without limitation, adhesive pellets may have regular shapes, irregular shapes, or any combination thereof. Moreover, any two pellets may have distinct shapes and/or dimensions and still be jointly and generally referred to as “adhesive pellets.” Furthermore, the collective adhesive particulate stored within the adhesive bin  10  includes a plurality of gaps between individual pieces of adhesive particulate. Gas, such as ambient air, is “entrained” within each of the gaps around the individual pieces of adhesive particulate. As used herein, the term “entrained” refers to gas generally within and around the collective adhesive particulate stored within the adhesive bin  10 . As such, “entrained” should not be limited to entrapping or sealing gas within the collective adhesive particulate or individual pieces of adhesive particulate. Rather, the term “entrained” refers to gas within the adhesive bin  10  that is at least partially surrounded by adhesive particulate. 
         [0018]    The adhesive bin  10  includes a supply hopper  16  having a lid  18  movable between open and closed positions. The supply hopper  16  is formed from at least one sidewall. In the exemplary embodiment, the at least one sidewall includes a front sidewall  20  and an opposing rear sidewall  22 . A pair of opposing lateral sidewalls  24 ,  26  each extend between the front and rear sidewalls  20 ,  22  such that the supply hopper  16  is generally rectangular in shape. Furthermore, an upper portion  28  of the supply hopper  16  includes a plurality of ribs  30  positioned on each of the front, rear, and lateral sidewalls  20 ,  22 ,  24 ,  26  for improving the rigidity of the upper portion  28 . A lower portion  32  of the supply hopper  16  also includes a bottom  34  extending transversely between each of the front, rear, and lateral sidewalls  20 ,  22 ,  24 ,  26 . In this respect, the sidewalls  20 ,  22 ,  24 ,  26  and bottom  34  collectively define an interior space  36  for receiving and storing adhesive particulate. According to the exemplary embodiment, the front sidewall  20  also includes a window  35  for viewing the interior space  36 . The window  35  is connected to the front sidewall  20  via a plurality of window fasteners  37 . For example, the window  35  is generally transparent; however, the window  35  may also be generally translucent for viewing the interior space  36  to see the level of adhesive particulate within the interior space  36  in accordance with the invention described herein. 
         [0019]    The lid  18  covers an opening (not shown) into the interior space  36  when in the closed position. The opening (not shown) is generally square and defined by the upper portion  28  of the supply hopper  16  for receiving adhesive particulate from above the adhesive bin  10 . The lid  18  pivots about a hinge  38  adjacent to the rear sidewall  22  for moving between open and closed positions. Furthermore, the lid  18  includes a pair of handles  40  for manipulating the lid  18  between open and closed positions. 
         [0020]    The adhesive bin  10  also includes a pair of wheels  42  and a pair of support members  44  for supporting the supply hopper  16  on a floor  46 . Each of the wheels  42  are positioned on ends of an axle  48  extending through the lower portion  32  of the supply hopper  16  generally parallel to the rear sidewall  22 . The wheels  42  are generally positioned adjacent to the rear sidewall  22  and straddle the opposing lateral sidewalls  24 ,  26 . Each support member  44  is positioned on the bottom  34  adjacent to the front sidewall  20  and one of the lateral sidewalls  24 ,  26 . Thus, in the event that the adhesive bin  10  rests on the floor  46 , the wheels  42  and the support members  44  provide four points of contact with the floor  46  for stability. In the event that the adhesive bin  10  needs to be moved along the floor  46 , the adhesive bin  10  may pivot upward about the wheels  42  for lifting the support members  44  off of the floor  46  and rolling the adhesive bin  10  to another position. The particular structure and shape or profile formed by the adhesive bin  10  may be modified in other embodiments without departing from the scope of the invention. 
         [0021]    The adhesive bin  10  further includes an adhesive transfer assembly  49  configured for moving the adhesive particulate from the interior space  36  to the adhesive melter  12 . The adhesive transfer assembly  49  is generally mounted to a recessed portion  51  of the rear sidewall  22  with a plurality of fasteners  50 . The recessed portion  51  tapers into the interior space  36  for defining an assembly volume  52  in which the adhesive transfer assembly  49  is generally positioned. A mount panel  53  is also connected to the rear sidewall  22  for providing a rigid location for mounting various connections and conduits. Although the mount panel  53  and recessed portion  51  are shown angled from a horizontal orientation and a vertical orientation, respectively, it will be understood that the mount panel  53  and recessed portion  51  may be oriented in different orientations in other embodiments without departing from the scope of the invention, including horizontal and vertical orientations. For example, in an alternative embodiment, the recessed portion  51  may be positioned substantially flush with the remainder of the rear sidewall  22 . A gas source  54  for supplying a gas supply, such as shop air, is fluidly connected to a supply conduit  55  connected to the mount panel  53 . The supply conduit  55  directs the gas supply to a manifold assembly  56 . According to an exemplary embodiment, the gas supply first routes through a filter  58  of the manifold assembly  56  and then to the remaining portion of the adhesive transfer assembly  49  to diminish the likelihood of foreign particles damaging the components of the adhesive transfer assembly  49 . 
         [0022]    From the manifold assembly  56 , the gas supply is directed by a controller  60  to a transfer pump  62 , such as a pneumatic pump, and a vibrator  64 , each of which is connected to the recessed portion  51  of the rear sidewall  22 . A power cord  66  is connected to the mount panel  53  for electrically connecting to a power supply  68  of the controller  60 . As such, the controller  60  operatively directs the gas supply through a coupling  70 . The coupling  70  splits the gas supply into a first gas supply portion and a second gas supply portion. The first gas supply portion flows from the coupling  70  to a pump gas inlet  72  via a pump gas conduit  74  for operating the transfer pump  62 . Meanwhile, the second gas supply portion flows from the coupling  70  to a vibrator gas inlet  76  via a vibrator gas conduit  78  for operating the vibrator  64 . In this respect, the gas supply may simultaneously be used to operate the transfer pump  62  and the vibrator  64 . According to an exemplary embodiment, the gas supply is pressurized at approximately 65 psi and adapted to provide at least approximately 21 cubic feet per minute (cfm) of gas. With respect to the exemplary transfer pump  62  and the exemplary vibrator  64 , the transfer pump  62  uses approximately 12 cfm as a venturi pump for operation while the vibrator  64  uses the remaining gas supply for operation. 
         [0023]    With respect to  FIG. 2  and  FIG. 3 , the transfer pump  62  includes an inner pump housing  80 , which defines a pump inlet  82 , and an outer pump housing  84 , which defines a pump outlet  86 . The inner and outer pump housings  80 ,  84  are connected to the recessed portion  51  of the rear sidewall  22 . Specifically, the inner pump housing  80  extends from the recessed portion  51  to within the interior space  36 , and the outer pump housing  84  extends outwardly from the recessed portion  51 , away from the interior space  36 . As such, the pump inlet  82  fluidly connects with the pump outlet  86 . In turn, the pump outlet  86  is fluidly connected to the adhesive melter  12  for moving the adhesive particulate through the transfer pump  62  and to the adhesive melter  12 . 
         [0024]    The vibrator  64  is mounted to the recessed portion  51  via vibrator fasteners  88 . The gas supply powers the vibrator  64  to operatively vibrate the recessed portion  51  for reducing compaction of the adhesive particulate within the interior space  36  adjacent to the pump inlet  82 . According to an exemplary embodiment, the gas supply exhausting from a vibrator outlet  90  is directed into the interior space  36  via an exhaust gas conduit  92 . Alternatively, the gas supply exhausting from the vibrator outlet  90  may be directed outside of the interior space  36 . However, by routing the exhaust gas conduit  92  as shown in  FIG. 2  and  FIG. 3 , the exhausting gas supply is effectively used as additional “make-up” gas for improving the efficiency of the transfer pump  62 . As described herein, the term “make-up” gas generally refers to gas within the supply hopper  16  drawn into the pump inlet  82  from around the adhesive particulate during use. The make-up gas may be provided actively, such as pumping gas directly into the interior space  36 , or passively, such as drawing entrained gas from gaps and other spaces around the adhesive particulate. According to an exemplary embodiment, the actively provided make-up gas and/or passively provided make-up gas are provided at least proximate to the pump inlet  82  for improving the efficiency of the transfer pump  62 . 
         [0025]    As described above, the exhausting gas supply from the vibrator  64  is routed proximate to the pump inlet  82  via the exhaust gas conduit  92 . More particularly, the exhaust gas conduit  92  includes an exhaust conduit outlet  93  and extends through the recessed portion  51  of the rear sidewall  22  and into the interior space  36 . According to an exemplary embodiment, the exhausting gas supply provides a preferred source of make-up gas because it is already sealed and filtered within the adhesive transfer assembly  49  as described above. However, it will be appreciated that other sources of make-up gas for exhausting proximate to the pump inlet  82  may also be used. In any case, the exhaust conduit outlet  93  is positioned generally proximate to the pump inlet  82 . 
         [0026]    With respect to  FIG. 3  and  FIG. 4 , the gas supply actuates the transfer pump  62  to generate a vacuum at the pump inlet  82  for withdrawing gas through the pump inlet  82  as shown by arrow  95   a.  As the gas moves into the pump inlet  82 , the gas actuates removal of the adhesive particulate by picking up and carrying adhesive particulate proximate to the pump inlet  82  into the transfer pump  62 . However, without an amount of make-up gas being readily available proximate to the pump inlet  82 , the efficiency of the transfer pump  62  is reduced. In this respect, actively providing make-up gas proximate to the pump inlet  82  as shown by arrow  95   b  improves the efficiency of the transfer pump  62 . 
         [0027]    The adhesive bin  10  also includes a shroud  94  for minimizing a depth of adhesive particulate located directly above the pump inlet  82 . The shroud  94  is connected to an inner surface  96  of the recessed portion  51  and extends from the inner surface  96  into the interior space  36  so as to at least partially surround the inner pump housing  80 . The shroud  94  includes a cover panel  98  vertically above the pump inlet  82 . A medial panel  100  is connected on each side of the cover panel  98  for further widening the shroud  94  above the inner pump housing  80 . Finally, a side panel  102  extends downward from each of the medial panels  100 , and a bottom panel  104  extends between the pair of side panels  102 . In this respect, the inner pump housing  80  is completely surrounded by the shroud  94  in the exemplary embodiment. Moreover, the bottom panel  104  also includes a recess  106  to help assist the adhesive particulate in filling up and covering the pump inlet  82  during use. However, it will be appreciated that the shroud  94  may be shaped or formed into various configurations. As such, the shroud  94  is not intended to be limited to the exemplary embodiment described herein. For example, the bottom panel  104  and/or other panels may be omitted in other embodiments of the adhesive bin  10 . 
         [0028]    As the adhesive particulate falls into the interior space  36  while being filled, the shroud  94  effectively deflects the adhesive particulate and prevents the adhesive particulate from stacking with a large depth directly above the inner pump housing  80 . As described in more detail below, the large depth or variable depth of particulate adhesive that results when the shroud  94  is not present makes it more difficult for the pump inlet  82  to draw make-up air from the surrounding environment. In this respect, the shroud  94  and inner pump housing  80  collectively define a gas space  108  that may entrain additional gas proximate to the pump inlet  82 . The entrained gas within the gas space  108  may then be used as make-up gas for improving the efficiency of the pump. In addition, the gas space  108  is sized above the pump inlet  82  so as to provide a consistent minimized depth d c  of adhesive particulate in which the pump inlet  82  is positioned. The consistent minimized depth d c  is generally defined as the depth of adhesive particulate from the top of the gas space  108  to the pump inlet  82 . In contrast, the adhesive particulate generally has a variable depth d v  above the pump inlet  82  that lowers as the transfer pump  62  moves the adhesive particulate from the supply hopper  16 . The variable depth d v  is generally defined as the depth of the adhesive particulate from an upper surface of the adhesive particulate to the pump inlet  82 . Specifically, the variable depth d v  is greater than the consistent minimized depth d c  until the supply hopper  16  is substantially empty. At this point, the variable depth d v  is generally equal to the consistent minimized depth d c . According to an exemplary embodiment, the pump inlet  82  is not submerged at a depth greater than the consistent minimized depth d c , because the shroud  94  and the gas space  108  are positioned vertically above the pump inlet  82 . Thus, when the variable depth d v  is greater than the consistent minimized depth d c , the transfer pump  62  effectively withdraws make-up gas from the gas space  108  along the lesser depth d c , and this further improves pumping efficiency. 
         [0029]    Furthermore, the vibrator  64  is rigidly connected to the recessed portion  51 , which is rigidly connected to the shroud  94 . Thus, the vibrations created by the vibrator  64  also vibrate the shroud  94 , which extends even further into the interior space  36  than the recessed portion  51 . The vibration of the shroud  94  further loosens the adhesive particulate proximate to the pump inlet  82  and, in turn, provides for additional entrainment of make-up gas around the adhesive particulate for improving the efficiency of the transfer pump  62 . Consequently, the position of the shroud  94 , the vibrations of the vibrator  64 , and the delivery of gas supply through the exhaust gas conduit  92  may collectively be used to increase entrained make-up gas available proximate to the pump inlet  82 . This additional access to make-up air, in combination with the consistent minimized depth of particulate adhesive located above the pump inlet  82 , enables a more efficient pumping operation. 
         [0030]    While the present invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features shown and described herein may be used alone or in any combination to provide advantageous and efficient operation of the transfer pump. For example, it will be appreciated that the shroud and the vibrator may be used exclusively or in combination for further improving the efficiency of the transfer pump. Thus, the invention is not intended to be limited to the combination of the vibrator and transfer pump as described herein. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method and illustrative examples shown and described. Accordingly, departures may be from such details without departing from the scope of the general inventive concept.