Patent Publication Number: US-6986651-B2

Title: Pump priming apparatus

Description:
BACKGROUND OF THE INVENTION 
   In order to remove fluid material from a container of such material, and particularly in the event that the container of fluid material contains substantially more fluid material than is needed at any given point in time, the fluid material is typically pumped out of the container in the desired quantity. This holds true for a variety of fluid materials, including but not limited to highly viscous lubricating fluids such as high viscosity grease. However, in order to pump such materials from a container, the material must first be drawn into the pumping device. This initial drawing in of material into the pumping device is referred to by those of ordinary skill in the art as “priming” the pump. In sum, in order for a pump to effectively remove fluid from a container, the pump must first be primed. When the fluid material is highly viscous, the sheer inertia of the still fluid is substantial and such inertia must be overcome in order to prime the pump. Therefore, to prime a pump with highly viscous fluid, the priming mechanism of the pump must impart enhanced force on the fluid. 
   Prior art pump priming mechanisms address the problem of priming pumps with highly viscous fluid materials in a variety of ways. One such way is the creation of a partial vacuum which is then released, causing a sudden equalization of air pressure that urges the high viscosity material into the pump. As used herein, the term “partial vacuum” means an air pressure lower than an ambient air pressure. 
   One prior art example of the utilization of sudden release of a partial vacuum for pump priming is U.S. Pat. No. 4,249,868 to Kotyk. The Kotyk patent discloses a pump with a priming mechanism designed to address the problem of pumping high viscosity material. In the Kotyk pump, the piston travels within a cylindrical valve, which in turn travels within the pump cylinder. When the piston completes a downstroke, the cylindrical valve blocks the inlet of the pump. On the upstroke, the piston creates a partial vacuum within the cylindrical valve until the piston reaches the top of the cylindrical valve and lifts the valve such that the inlet is reopened. Upon the reopening of the inlet, the partial vacuum in the cylindrical valve is released and the sudden equalization of pressure causes the fluid material at the inlet to rush into the cylindrical valve before proceeding into the succeeding stages of the pump. 
   In contrast to Kotyk and other partial vacuum priming devices in the prior art, the pump priming apparatus of the present invention provides a simple piston and cylinder structure to accomplish the priming without the need for additional parts that ultimately add expense to the construction and maintenance of the pump while diminishing its reliability. 
   SUMMARY OF THE INVENTION 
   One embodiment of the invention is a pump priming apparatus including a housing through which fluid object material may be urged to flow, the housing including an intake portion and a pumping portion downstream from the intake portion. This apparatus embodiment of the invention further includes a piston assembly carried for reciprocation in the housing, the piston assembly and the housing being configured such that a partial vacuum is developed in the pumping portion of the housing as the piston assembly moves through the pumping portion of the housing toward the intake portion of the housing and such that the partial vacuum is substantially released upon the movement of the piston assembly into the intake portion of the housing, thereby causing the fluid object material in the intake portion of the housing to flow into the pumping portion of the housing. 
   Another embodiment of the invention is a method of priming a pump for pumping fluid object material, the method including the steps of providing a pump priming apparatus comprising a housing through which fluid object material may be urged to flow, the housing including an intake portion and a pumping portion downstream from the intake portion. Additional steps of this method embodiment of the invention include placing the intake portion of the housing in the fluid object material to be pumped, creating a partial vacuum in the pumping portion of the housing, substantially releasing the partial vacuum in the pumping portion of the housing, thereby causing the fluid object material to flow from the intake portion of the housing into the pumping portion of the housing, and pumping the fluid object material out of the pumping portion of the housing. 
   Yet another embodiment of the invention is a pump priming apparatus including means for carrying a flow of fluid object material therethrough, the carrying means including an intake portion and a pumping portion downstream from the intake portion. This apparatus embodiment of the invention further includes means for urging the fluid object material through the carrying means, the urging means and the carrying means being configured such that a partial vacuum is developed in the pumping portion of the carrying means as the urging means moves through the pumping portion of the carrying means toward the intake portion of the carrying means, and such that the partial vacuum is substantially released upon the movement of the urging means into the intake portion of the carrying means, thereby causing the fluid object material in the intake portion of the carrying means to flow into the pumping portion of the carrying means. 
   Yet another embodiment of the invention is a method of priming a pump for pumping fluid object material, the method including the steps of providing a pump priming apparatus comprising a means for carrying a flow of fluid object material therethrough, said carrying means comprising an intake portion and a pumping portion downstream from the intake portion. Additional steps of this method embodiment of the invention include placing the intake portion of the carrying means in the fluid object material to be pumped, creating a partial vacuum in the pumping portion of the carrying means, substantially releasing the partial vacuum in the pumping portion of the carrying means, thereby causing the fluid object material to flow from the intake portion of the carrying means into the pumping portion of the carrying means, and pumping the fluid object material out of the pumping portion of the carrying means. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present disclosure may be better understood when taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a perspective view of a pump priming apparatus according to an embodiment of the invention; 
       FIG. 2  is an exploded view of a piston according to an embodiment of the invention; 
       FIG. 3  is a bottom plan view of a valve according to an embodiment of the invention; and 
       FIGS. 4 ,  5 ,  6 , and  7  are cross-sectional views of the pump priming apparatus of  FIG. 1  taken through line  4 — 4  in  FIG. 1 , illustrating four positions successively occupied by an embodiment of a piston according to the invention during one full downstroke of the piston in the cylinder. 
   

   DETAILED DESCRIPTION 
   Referring now to the drawings,  FIG. 1  illustrates a pump priming apparatus  10  according to an embodiment of the present invention. The basic components of the pump priming apparatus  10  are the cylinder  11 , the piston rod  12 , and the piston  13 . The piston  13  is carried on one end of the piston rod  12 , which reciprocates in the cylinder  11  during operation of the pump priming apparatus  10 . The cylinder  11  is provided with a threaded portion  14  for interfacing with an adjacent section of the pump (not shown). The cylinder  11  has a proximal end  15  and a distal end  16 ; the proximal end  15  includes the threaded portion  14  of the cylinder  11 . A pumping portion  20  of the cylinder  11  is adjacent to the proximal end of the cylinder  11 , while an inlet portion  21  of the cylinder  11  is adjacent to the distal end  16  of the cylinder  11 . The inlet portion  21  defines a plurality of inlet ports  22  for allowing fluid material (not shown) to flow into the cylinder  11 . The inlet ports  22  allow the fluid material to flow into the cylinder  11  when the distal end  16  of the cylinder  11  is resting on the bottom of a container (not shown) of fluid material. 
   Turning now to  FIG. 2 , the construction of the piston  13  is shown. A disc valve  23  comprises the central portion of the piston  13 . The disc valve  23  includes a upper valve portion  24  having a upper major valve surface  25  facing toward the piston rod  12  and a lower valve portion  26  having a lower major valve surface  30  facing away from the piston rod  12 . A chamfer  31  sloping radially outward from the periphery of the upper valve portion  24  to the periphery of the lower valve portion  26  results in the diameter of the upper valve portion  24  being smaller than the diameter of the lower valve portion  26 . The valve  23  defines a centrally disposed port  32  that enables the fastening of the valve  23  as part of the piston  13 . Furthermore, as shown in  FIG. 3 , the valve  23  defines a weep hole  33  for preventing the piston  13  from seizing in the cylinder  11 , as described further below. 
   Turning back to  FIG. 2 , the piston  13  further includes a washer  34  and a hexagonal nut  35 , which engage the upper and lower major valve surfaces  25 ,  30 , respectively, when the piston  13  is fully assembled. The washer  34  and the nut  35  each define respective centrally disposed ports  36 ,  40  that align with the centrally disposed port  32  defined by the valve  23  when the piston  13  is assembled. 
   Still referring to  FIG. 2 , the piston  13  is fastened to the piston rod  12  as follows. A piston-engaging end  41  of the piston rod  12  carries a threaded bolt shank  42 . An internally threaded sleeve  43  is provided for receiving the bolt shank  42 . The bolt shank  42  and the sleeve  43  are screwed together and carry the piston  13  by insertion through the centrally disposed ports  32 ,  36 ,  40  of the valve  23 , the washer  34 , and the nut  35  of the piston  13 . 
   Turning now to  FIGS. 4 ,  5 ,  6 , and  7 , the piston rod  12 , the piston  13 , and the interior of the cylinder  11  are more visible and four successive stages of one complete downstroke of the piston  13  are shown. It can be seen from these drawings that the inner diameter of the pumping portion  20  of the cylinder  11  is smaller than the inner diameter of the inlet portion  21  of the cylinder  11 . This variance in the inner diameter of the cylinder  11  is directly related to the outer diameter of the piston  13 . Specifically, the outer diameter of the piston  13  is nearly equal to the inner diameter of the pumping portion  20  of the cylinder  11 , but is smaller than the inner diameter of the inlet portion  21  of the cylinder  11 . 
   This variation in the inner diameter of the cylinder  11  and its relation to the outer diameter of the piston  13  enables a pressure differential and equalization to occur during the movement of the piston  13  in the cylinder  11 . As the piston  13  moves on a downstroke beginning from the proximal end  15  of the cylinder ( FIG. 4 ) through the pumping portion  20  of the cylinder  11  (FIG.  5 ), a partial vacuum is developed in the pumping portion  20  of the cylinder  11 . As the piston  13  continues its downstroke toward the distal end  16  of the cylinder  11  by moving into the inlet portion  21  of the cylinder  11  (FIG.  6 ), the partial vacuum in the pumping portion  20  of the cylinder  11  is substantially released and the pressures in the pumping portion  20  and the inlet portion  21  suddenly equalize, forcing the fluid material in or near the inlet portion  21  of the cylinder  11  to be drawn into the pumping portion  22  of the cylinder  11 . 
   The weep hole  33  ( FIG. 3 ) defined by the valve  23  allows a small amount of air and/or fluid material in the cylinder  11  to flow back and forth between the pumping portion  20  and the inlet portion  21  of the cylinder  11  (FIGS.  4 , 5 , 6 , 7 ) as the piston  13  moves within the cylinder  11 . This small air and/or fluid material flow helps prevent the partial vacuum created in the cylinder  11  during operation of the apparatus  10  from becoming so strong as to cause the piston  13  to be immobilized in the cylinder  11 . However, the flow enabled by the weep hole  33  does not detract from the above-described priming action of the apparatus  10 . 
   After the piston  13  reaches the distal end  16  of the cylinder  11  to complete its downstroke (FIG.  7 ), the piston  13  begins its upstroke in the cylinder  11  by traveling back toward the proximal end  15  of the cylinder  11 . The order of the piston positions discussed above and shown in  FIGS. 4 ,  5 ,  6 , and  7  need only be reversed to view various stages of the upstroke motion of the piston  13 . On its upstroke, the piston  13  forces the fluid material in the cylinder  11 , and especially the fluid material in the pumping portion  20  of the cylinder  11 , out of the cylinder  11  through an opening  44  in the proximal end  15  of the cylinder  11  and into an adjacent section of the pump (not shown). 
   Although the above description and the accompanying drawings describe embodiments of the cylinder, piston, and valve of the present invention that are cylindrical and/or annular in shape, similar results may be achieved with elements of varying shapes, so long as the seal between the valve on the piston and the pumping portion of the pump priming apparatus is sufficient to create the desired partial vacuum in the pump priming apparatus and so long as the partial vacuum may be released to cause the flow of fluid material into the pump priming apparatus. Similarly, the composition of the various elements of the pump priming apparatus may also vary so long as the necessary functions of those elements are still served. 
   A pump priming apparatus is described above. Various details of the invention may be changed without departing from its scope. Furthermore, the foregoing description of the invention and the best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation—the invention being defined by the claims.