Patent Publication Number: US-8118070-B2

Title: Disconnect valve for gravity fed paint hoppers

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to the field of paint sprayers, more particularly to paint spray pumps having a gravity fed paint hopper to deliver paint to the pump. Some prior art systems did not have a convenient way to remove the hopper from the pump; consequently, during clean-up of the equipment after spraying water-based paint, the electric motor associated with the pump was undesirably subjected to water spray used to clean the hopper. Even if the user desired to remove the hopper from the pump for clean-up in such prior art systems, there typically was no convenient means to shut off paint from the hopper when the hopper was removed from the pump. Since the paint was fed from the hopper to the pump by gravity, removing the hopper would allow paint to leak from the hopper once the hopper outlet was separated from the pump inlet. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention overcomes this shortcoming of the prior art by providing a removable hopper with an automatic shut-off that closes the hopper outlet when the hopper is removed from the pump inlet below the hopper outlet. This enables a user, for example, to conveniently return unused paint remaining in the hopper to a storage container, and makes it easier and more convenient for the user to clean-up the hopper after spraying is completed. In addition, in at least one embodiment, residual paint remaining on the outlet may be automatically wiped off in the process of separating the hopper outlet from the pump inlet, eliminating or at least reducing the potential for paint to drip off the hopper outlet once it is separated from the pump inlet. 
     In one aspect of the present invention, a valve closes automatically when the hopper outlet is separated from the pump inlet. The valve may be held open (for gravity feeding of the paint when the hopper is connected to the pump inlet) by a projection extending from a structure subjacent the hopper outlet and attached to the pump inlet. 
     In another aspect, paint remaining on the hopper outlet is wiped off the outlet as the hopper is removed. The projection which operates the valve may support a wiper to accomplish this aspect of the invention. In one form, the outlet may be a conical extension, and, in another embodiment, the outlet may be a cylindrical extension. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective view from above and to the left of a prior art paint spray pump and hopper. 
         FIG. 2  is a view similar to that of  FIG. 1 , except from above and to the right and with a lid displaced from the hopper. 
         FIG. 3  is a fragmentary section view of the prior art pump and hopper shown in  FIG. 1 , taken along line III-III. 
         FIG. 4  is an exploded fragmentary section view of the prior art parts shown in  FIG. 3 . 
         FIG. 5  is a perspective view from above and to the right of a paint spray pump with a user removable hopper useful in the practice of the present invention. 
         FIG. 6  is a side elevation view of the paint spray pump and hopper of  FIG. 5 , partly cut away and in section along line VI-VI. 
         FIG. 7  is an enlarged view of the section view of  FIG. 6 , showing the hopper attached and with the disconnect valve open to provide fluid communication from the hopper to the pump. 
         FIG. 8  is a view similar to that of  FIG. 7 , except with the hopper detached and with the disconnect valve closed to prevent liquid from draining from the hopper. 
         FIG. 9  is side elevation view of a pump inlet sleeve for the disconnect valve, useful in the practice of the present invention. 
         FIG. 10  is a top plan view of the pump inlet sleeve of  FIG. 9 . 
         FIG. 11  is a side section view of the pump inlet sleeve taken along line XI-XI of  FIG. 10 . 
         FIG. 12  is a fragmentary section view of a hopper outlet and paint pump inlet in an alternative embodiment of the present invention, shown with the outlet connected to the inlet in a normal operating condition. 
         FIG. 13  is a view similar to that of  FIG. 12 , except with the hopper and hopper outlet partially displaced from the pump inlet in the process of being removed, to illustrate certain aspects of the present invention. 
         FIG. 14  is a view similar to that of  FIG. 13 , except with the hopper outlet fully separated from the pump inlet. 
         FIG. 15  is a top plan view of a strainer and valve guide shown in  FIG. 12 . 
         FIG. 16  is a side elevation view of the strainer and valve guide of  FIG. 12 . 
         FIG. 17  is a section view taken along line XVII-XVII of  FIG. 16 . 
         FIG. 18  is a fragmentary section view of a hopper outlet and paint pump inlet in a second embodiment of the present invention, with the outlet connected to the inlet in a normal operating condition. 
         FIG. 19  is a view similar to that of  FIG. 18 , except with the hopper outlet partially displaced to a first intermediate position in the process of separating the hopper outlet from the paint pump inlet. 
         FIG. 20  is a view similar to that of  FIG. 19 , except with the hopper outlet further displaced to a second intermediate position in the process of separating the hopper outlet from the paint pump inlet. 
         FIG. 21  is a view similar to that of  FIG. 20 , except with the hopper outlet fully separated from the pump inlet. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the Figures, and most particularly to  FIGS. 1-4 , a prior art paint spray pump assembly  10  may be seen. Pump assembly  10  preferably includes an electric motor driven pump  12  located below a paint hopper  14 . The various details of assembly  10  are shown and described in commonly assigned U.S. Pat. No. 7,018,181, the entire contents of which are hereby expressly incorporated by reference. 
     In prior art versions of this equipment, the hopper  14  was secured to the pump  12  using a pair of bolts  16 , as shown most clearly in  FIG. 2 . While this provided a secure connection between the hopper  14  and the pump  12 , it also meant that the user could not conveniently remove the hopper from the pump, especially when some paint remained in the hopper. Even if a user were to remove the bolts  16  so that the hopper  14  could be removed from the pump  12 , any remaining paint in the hopper would then spill out of an outlet  18  of the hopper when the hopper was withdrawn from a paint pump inlet  22 .  FIG. 3  shows a partial cross section of the assembly  10  in an operating condition where the hopper outlet  18  is connected to a subjacent structure  20  including the pump inlet  22 .  FIG. 4  is a view similar to that of  FIG. 3 , except with the assembly partially exploded to illustrate that when the outlet  18  of the hopper  14  is separated from the pump inlet  22 , any material remaining in the hopper  14  will be free to drain by gravity through the open outlet  18 . 
     The prior art version of this equipment may thus be seen to have shortcomings in that the entire assembly  10  may be required to be lifted and tilted to empty excess paint remaining in the hopper  14  after spraying is completed. In addition, the hopper  14  is not readily removed from the remainder of assembly  10  for cleaning, thus increasing the risk that a user will spray the hopper  14  with a garden hose while the hopper is attached to the pump  12 , which may undesirably subject the electric motor associated with the pump  12  to water overspray. 
     Referring now most particularly to  FIGS. 5-8 , a paint spray pump and hopper combination  11  useful in the practice of the present invention may be seen. In  FIGS. 7 and 8  various details and aspects of this embodiment of a disconnect apparatus  25  for the present invention may be seen. Apparatus  25  automatically operates to open and close a gravity-type connection between the removable hopper  15  and a subjacent structure  21 . The apparatus  25  includes an outlet  19  of the hopper  15  located at a lowermost portion  27  of the hopper and a valve  29  located in the outlet  19 , with the valve automatically positioned to: i) an OPEN condition  31  (shown in  FIG. 7 ) and ii) a CLOSED condition  33  (shown in  FIG. 8 ), depending upon whether the hopper  15  is positioned on or removed from the pump  13 . 
     The valve  29  is held in the OPEN condition  31  when the outlet  19  of the hopper  15  is connected to the subjacent structure  21 , as is shown in  FIG. 7 . As shown in  FIG. 8 , the valve  29  moves to a closed condition  33  when the outlet  19  of the hopper  15  is removed from the subjacent structure  21 . As shown in these Figures, the subjacent structure  21  may include a pump inlet  23 . 
     As illustrated in  FIG. 7 , the apparatus  24  also may include means  35  for opening the valve  29  when the outlet  19  of the hopper  15  is connected to the subjacent structure  21 . The means for opening the valve is mounted on the subjacent structure. The means for opening the valve includes the structure of a projection  37  extending toward the valve  29 , more particularly the projection  37  may be formed as a part of an inlet sleeve  41 . The valve  29  may have a stem  43  and a head  45  arranged to engage a seat  47  when the valve  29  is in the CLOSED condition  33 . The outlet  19  is preferably, but not necessarily, cylindrical. In the operation of the valve  29  of the present invention, the projection  37  presses against the head  45  of the valve  29  to move the valve  29  to the OPEN condition  31  when the outlet  19  of the hopper  15  is connected to the pump inlet  23 . A spring  49  urges the valve  29  toward the CLOSED condition  33  in which the head  45  seals against the seat  47 , preventing flow from the outlet  19 . 
     A strainer and valve guide  51  may be used to locate and support the valve  29  in the outlet  19 . Guide  51  provides a reaction surface  53  against which spring  49  reacts to urge the valve  29  to the CLOSED condition  33 . 
     A valve retainer  63  is preferably threaded onto the outlet  19  and secures the guide  51  to the outlet  19  of the hopper  15 . Retainer  63  also preferably has valve seat  47  formed integrally therewith. The valve  29 , valve guide  51  and valve retainer  63  may be formed of a polymeric material resistant to degradation in the presence of conventional paints and paint solvents, and other similar coating materials and their respective solvents. 
     Referring now to  FIGS. 9 ,  10 , and  11 , various details of the inlet sleeve  41  may be seen. Sleeve  41  may form the pump inlet  23  and includes projection  37  surrounded by a plurality of apertures  61 . Threads  55  may be used to secure sleeve  41  to the pump  13 , and threads  57  may further secure sleeve  41  in a pump housing a threaded ring  65 . 
     Various details and aspects of another embodiment of a disconnect apparatus  24  (similar to apparatus  25 ) useful in the practice of the present invention may be seen in  FIGS. 12 ,  13  and  14 . Apparatus  24  automatically operates (i.e., opens and closes) a gravity-type connection between a removable hopper  14 ′ and a subjacent structure  20 .′ The apparatus  24  includes an outlet  18 ′ of the hopper  14 ′ located at a lowermost portion  26  of the hopper and a valve  28  located in the outlet  18 ′, with the valve  28  positionable between OPEN and CLOSED conditions. The valve  28  is held in an OPEN condition  30  when the outlet  18 ′ of the hopper  14 ′ is connected to the subjacent structure  20 ,′ as shown in  FIG. 5 . As shown in  FIGS. 6 and 7 , the valve  28  moves to a CLOSED condition  32  when the outlet  18 ′ of the hopper  14  is removed from the subjacent structure  20 .′ As shown in these Figures, the subjacent structure  20 ′ may include a pump inlet  22 .′ 
     As illustrated in  FIG. 12 , the apparatus  24  also may include means  34  for opening the valve  28  when the outlet  18 ′ of the hopper  14 ′ is connected to the subjacent structure  20 .′ The means for opening the valve is mounted on the subjacent structure. The means for opening the valve includes the structure of a projection  36  extending toward the valve  28 , more particularly the projection  36  may be a perforated cylinder  38  having a plurality of apertures  39  circumferentially spaced around the cylinder  38 . The valve  28  may be a poppet valve having a stem  40  and flange  42  with a rim  44  arranged to engage a seat  46  when the valve  28  is in the closed condition  32 . The outlet  18 ′ is preferably, but not necessarily, cylindrical. The valve  28  has a conical interface between the rim  44  and the seat  46 , with the cone direction of the conical mating surfaces inverted from that of conventional poppet valves such as those commonly used as intake and exhaust valves in internal combustion engines. In the operation of the valve  28  of the present invention, the projection  36  presses against the flange  42  of the valve  28  to move the valve  28  to the OPEN condition  30  when the outlet  18 ′ of the hopper  14 ′ is connected to the pump inlet  22 .′ A spring  48  urges the valve  28  toward the CLOSED condition  32  in which the rim  44  seals against the seat  46 , preventing flow from the outlet  18 .′ 
     A strainer and valve guide  50  for this embodiment may be seen in various views in  FIGS. 15 ,  16  and  17 . Guides  50  and  51  are similar. As shown in  FIGS. 12-14 , guide  50  locates and support the valve  28  in the outlet  18 .′ Guide  50  provides a reaction surface  52  against which spring  48  reacts to urge the valve  28  to the closed condition  32 . Guide  50  preferably has a perforated strainer portion  54  supported by a plurality of ribs  56  with a depending peripheral mounting flange  58  all integrally together. Guide  50  may have a cruciform opening  60  to receive the stem  40  in a sliding relationship. The stem  40  and opening  60  preferably have mating and loosely interfitting cruciform cross sections. 
     In the embodiment shown in  FIGS. 12-14 , valve retainer  62  is preferably threaded onto the outlet  18 ′ and secures the flange  58  of the guide  50  to the outlet  18 ′ of the hopper  14 .′ Retainer  62  also preferably has valve seat  46  formed integrally therewith. The valve  28 , valve guide  50  and valve retainer  62  may be formed of a polymeric material resistant to degradation in the presence of conventional paints and paint solvents, and other similar coating materials and their respective solvents. 
     Referring now to  FIGS. 18 ,  19 ,  20  and  21 , a still further embodiment  64  of the disconnect apparatus of the present invention may be seen. This embodiment provides an additional feature of automatically wiping paint off an interior surface  68  of the hopper outlet  70  downstream of a shutoff valve  74  while removing the hopper. This has the advantage of reducing the risk of dripping paint as and after the hopper is removed. In the embodiment of  FIGS. 18-21 , the apparatus  64  includes means  66  for wiping the interior  68  of the outlet  70  of the hopper  72  below (downstream of) the shutoff valve  74  when the outlet  70  of the hopper is removed from a subjacent structure  76 . The means for wiping  66  is preferably located on the subjacent structure  76 . Structure  76  includes a paint pump inlet  78 . The means for wiping  66  may include a peripheral surface  80  on a projection  82  mounted on the subjacent structure  76  and extending toward the valve. In one form, the means for wiping may include an O-ring  84 . 
     The apparatus may further include an outer wall  86  connected to the subjacent structure  76  and surrounding the projection  82 . As with the embodiment shown in  FIG. 12 , the projection  82  may include a perforated cylinder  88 . 
     The outlet  70  may include a cylindrical extension  90  having a circular opening with an inner diameter  92 . The projection  82  may include a cylindrical support  94  having an outer diameter  96  sized to closely interfit with the inner diameter  92  of the circular opening of the cylindrical extension  90  of the outlet  70 . The means for wiping  66  comprises a circumferential surface on the cylindrical support  94 . The cylindrical extension  90  has an axial length  98  and the projection  82  has a length  100  greater than the axial length  98  of the cylindrical extension  90 , so that the O-ring  84  (or other means for wiping) will traverse the entire downstream area of the outlet  70  as the hopper  72  is withdrawn from the pump inlet  78 , to provide complete wiping of the interior surface. 
     In another aspect, the present invention may be seen to be a method of providing a disconnect apparatus for a gravity-fed paint hopper comprising the steps of providing the paint hopper for containing paint, with the hopper located above the inlet of a paint pump and having an outlet located at the lowermost portion of the hopper, locating a valve in the outlet, urging the valve to an open condition when the hopper is connected to the inlet of the pump, and releasing the valve to move to the closed condition when the hopper is removed from the inlet of the pump. The invention may also include using a projection extending from the inlet of the pump to wipe paint from the outlet as the hopper is removed from the inlet of the pump. 
     In this method, the valve may be a poppet valve having a stem and the method may include guiding the stem of the valve as it moves. The method may also include wiping the bore, such as by using an edge of the projection to wipe the outlet. Alternatively, the method may use an O-ring mounted on the projection to wipe the outlet. 
     This invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the spirit or scope of the invention.