Abstract:
A double-acting, simplex, fluid handling pump is designed to facilitate an optional configuration as either a plunger pump or a diaphragm pump. An injection molded plastic pump body comprises two bilaterally symmetrical halves that include internal pockets and grooves for clamping and retaining first and second generally identical valve assemblies at opposing end portions of the pump body. When configured as a plunger pump, first and second plunger are arranged to move 180° out-of-phase with respect to one another within stationary guide sleeves that are clamped within the pump body where one plunger effecting a suction stroke while the other effects a compression stroke. When configured as a diaphragm pump, the plungers are removed from the connecting rods and replaced by diaphragms and a change is made in the valve casing employed but a majority of the remaining parts of the pump assembly remain unchanged from what is used in the plunger pump.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     I. Field of the Invention  
         [0002]     This invention relates generally to a double acting simplex fluid handling pump, and more particularly to such a pump having a housing that permits adaptation to either a plunger pump or a diaphragm pump using many of the same internal parts in each.  
         [0003]     II. Discussion of the Prior Art  
         [0004]     A variety of double acting fluid handling pumps are known in the art and are typically constructed so as to include a cast iron or aluminum housing, each of which requires rather extensive and costly machining. Such designs cannot be used to pump caustic chemicals because the housing and many of the internal parts of such prior art pumps become corroded, resulting in pump failure within a relatively short period of time.  
         [0005]     Thus, a need exists for a relatively low cost, long-lasting, simplex, double-acting pump capable of pumping both chemically inert liquids and caustic liquids. The present invention meets this need.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention comprises a fluid handling pump that is configurable either as a plunger pump or a diaphragm pump and that uses the same pump body and many of the internal working parts for each. The pump body itself is unique in that it comprises first and second bilaterally symmetrical halves that, when joined together about a midline, plane form an enclosed cavity. Each of the pump body halves includes a tubular pipe member with first and second ends. One of the first and second ends of the tubular pipe member on the first housing half comprises a low pressure fluid inlet port. In a like manner, one of the first and second ends of the tubular pipe member on the second pump body half comprises a high pressure fluid outlet port. The enclosed cavity defines first and second transversely extending pockets, each of which is in fluid communication with the lumens of the tubular pipe members and a longitudinally extending pocket that intersects with the first and second transversely extending pockets. Located in the longitudinally extending pocket are first and second reciprocally slidable connecting rod members that support either a plunger member, when the fluid handling pump is configured as a plunger pump, or a diaphragm when the fluid handling pump is configured as a diaphragm pump.  
         [0007]     Fitted individually into the first and second transversely extending pockets are first and second identical valve assemblies. Each of the valve assemblies comprises a tubular body that supports an inlet poppet valve and an outlet poppet valve in spaced apart relation in opposed ends of the tubular body. The tubular body of each of the valve assemblies includes a central opening that is generally aligned with either the plunger or the diaphragm, depending upon whether the fluid handling pump is configured as a plunger pump or a diaphragm pump. An eccentric is operatively coupled to the reciprocally slidable connecting rod members for imparting reciprocating strokes to the plunger or diaphragm.  
         [0008]     Although a die cast metal may be used, the pump body of the present invention is preferably an injection molded part formed from a suitable plastic, such as a polyester plastic material, preferably glass reinforced polybutylene terephthlate, and the only parts of the pump assembly that are not fabricated from an appropriate plastic are stainless steel springs forming part of the poppet valves. As such, the fluid-handling pump of the present invention is well suited for use in pumping a wide variety of corrosive chemicals. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0009]     Other features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several views refer to corresponding parts.  
         [0010]      FIG. 1  is a perspective view of the preferred embodiment of the present invention;  
         [0011]      FIG. 2  is a perspective view of an injection molded, plastic pump body half;  
         [0012]      FIG. 3  is a top plan view of the lower housing half shown in  FIG. 1  or a bottom view of the top pump body half shown in  FIG. 1 , the two being identical;  
         [0013]      FIG. 4  is a horizontal, longitudinal cross-sectional view taken in direction of the arrows  4 - 4  in  FIG. 1  when the pump is configured as a plunger pump;  
         [0014]      FIG. 5  is a view similar to that of  FIG. 4  when the pump in configured as a diaphragm pump;  
         [0015]      FIG. 6  is a top plan view of the valve assembly used in the pump of  FIG. 4  when configured as a plunger pump;  
         [0016]      FIG. 7  is a cross-sectional view taken along the line  7 - 7  in  FIG. 6 ;  
         [0017]      FIG. 8  is an exploded view of the valve assembly when the fluid handling pump is configured as a diaphragm pump;  
         [0018]      FIG. 9  is an exploded view of the entire fluid handling pump assembly when configured as a plunger pump; and  
         [0019]      FIG. 10  is an exploded view of the entire pump assembly when configured as a diaphragm pump. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the device and associated parts thereof Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import.  
         [0021]     Referring first to  FIG. 1 , there is illustrated a perspective view of the preferred embodiment of the double acting, simplex, fluid handling pump comprising a preferred embodiment of the present invention. The pump is indicated generally by numeral  10  and is shown as being attached to an electric drive motor  12  in a manner that will be described in greater detail herein below. The pump  10  includes a pump body  14  that comprises a lower body half  16  and an upper body half  18 , the two being bilaterally symmetrical and, therefore, being identical parts. Each is preferably injected molded from a suitable plastic, taking into account operating pressures, speeds and the nature of the fluid being pumped. A polyester plastic, and preferably glass reinforced polybutylene terephthlate has been found suitable for many applications. It is to be understood, however, that a die cast metal pump body can be used as well. The two body halves  16  and  18  are joined together about a midline plane  20  by nut and bolt fasteners as at  22  that pass through aligned apertures formed through the thickness dimension of laterally extending flange portions  23  and  25  of the upper and lower pump body halves,  18  and  16 , respectively.  
         [0022]     As seen in  FIG. 1 , the lower  16  and upper  18  body halves each include a tubular pipe member, with pipe member  24  forming a part of the lower body member  16  and tubular pipe  26  forming part of the upper pump body member  18 . Pipe member  24  has first and second ends  28  and  30 . Likewise, tubular pipe member  26  has first and second ends  32  and  34 . In use, either end  28  or  30  of the pipe member  24  may serve as a lower pressure fluid inlet port while the opposite end thereof is suitably capped by a threaded end cap (not shown). Likewise, either end of the pipe member  26  may serve as a high pressure fluid outlet port, again with the opposite end suitably capped with a screw-on cover (not shown). By having both ends of each of the tubular pipes  24  and  26  threaded, flexibility is afforded for the external connection of a fluid supply hose and a high pressure output hose.  
         [0023]     Further, and as will be explained in greater detail below, depending upon the orientation of valve assemblies within the pump body  14  either pipe member  24  or tubular pipe member  26  may serve as the low pressure manifold with the other functioning as the high pressure manifold.  
         [0024]     Turning next to  FIGS. 2 and 3 , the internal constructional features of the upper and lower pump body halves  16  and  18  can be viewed. Each of the upper and lower pump body halves has a planar surface  36  and formed inwardly thereof proximate opposed ends are first and second transversely extending pockets  38  and  40  leading to a flat annular surface  42  at the base of the pocket. The open center of the surface  42  leads to a bore (not shown) formed through the wall of the pipe members  24  and  26 .  
         [0025]     Located longitudinally inward of the pockets  38  and  40  are semicircular recesses  44  and  46  and centrally disposed between the two ends is a generally rectangular pocket  48 . The rear wall  50  of the pump body halves  16  and  18  each includes a semicircular opening  52  therein leading to the pocket  48 . The bottom surface  54  of the pocket  48  includes an arcuate groove  56  adjacent to the rear wall  50  and a longitudinal groove  58  of semicircular cross section approximately midway between the rear wall  50  and a front wall  60 .  
       Plunger Pump Configuration  
       [0026]     Attention is next directed to the cross sectional view of  FIG. 4  which shows the lower pump body half  16  when containing the internal parts for implementing a plunger pump. As can be seen, the semi circular opening  52  in the rear sidewall is designed to accept a cylindrical projection  62  formed on the front end of the drive motor  12  therethrough. The pump is joined to the motor by bolts, as at  63 . The motor shaft  64  extends into the rectangular pocket  48  and mounted thereon is an eccentric member  66  that is held in place on the shaft by a setscrew  68 . The eccentric  66  includes a centrally disposed cylindrical nose portion  70  that extends through the central opening of a ball bearing set  72 .  
         [0027]     A generally cylindrical shuttle member  74  has a notch  76  formed therein into which the bearing set  72  is made to fit with outer race. 78  abutting the shoulders  80  and  82  defining the opposed ends of the notch  72 .  
         [0028]     The shuttle member  74  includes cylindrical stubs  84  and  86  on opposed ends thereof and the stubs, in turn, include longitudinally extending threaded bores into which are screwed connecting rod members  88  and  90 . The connecting rod members may comprise shoulder bolts that pass through cylindrical, tubular plungers  92  and  94  that are preferably formed from a suitable ceramic and which are polished to provide a smooth, uniform outside cylindrical surface. The inner ends of the plunger members  92  and  94  are held in tight abutting relationship to the ends of the stubs  84  and  86  of the shuttle member  74  and O-rings, as at  96 , serve as a seal to prevent fluid leaking along the interface between the connecting rods  88  and  90  and their respective plungers  92  and  94  from reaching the desired dry portions of the pump assembly including the rectangular pocket  49  and the component parts located there.  
         [0029]     Next, turning momentarily to  FIGS. 6 and 7 , there is shown a valve assembly to be used when configuring the fluid handling pump as a plunger pump. The valve assembly is indicated generally by numeral  100  and includes a tubular valve casing  102  supporting an inlet poppet valve  104  and an outlet poppet valve  106  in spaced apart relation in the opposed end portions  108  and  110  of the tubular casing  102 . The  5  poppet valve assembly used in the device is entirely conventional and employ a spring to normally urge the disk-like poppet valves in sealed relation relative to a cooperating valve seat formed in the valve cage. The tubular casing  102  of the valve assembly  100  includes a central opening  112  leading to an internal chamber  114 . A somewhat frustoconically-shaped flange  115  is integrally molded with the tubular body  102  and it is adapted to fit into either of the recesses  44  or  46  of the pump body  16  such that the tubular valve casing occupies one of the pockets  38  and  40 . O-ring seals, as at  116  and  118 , cooperate with the annular surfaces  42  formed in the pockets  38  and  40  to provide sealing therebetween.  
         [0030]     As seen in  FIGS. 4 and 7 , a smooth carbon guide sleeve  120  is captured within a cylindrical tubular retainer  122  which fits into the central opening  112  of the valve casing and the inner end of the retainer  122  abuts a washer  124  that is used to hold an elastomeric cup seal  126 . As seen in  FIG. 4 , the plunger  92  passes through the carbon guide sleeve  120  and cooperates with the cup seal  126  to preclude fluid flow along the OD of the plunger  92 . The plunger  94  has an identical guide and seal arrangement. The exploded view of  FIG. 9  will aid the reader in understanding the overall construction manner in which the plunger pump is assembled.  
       Operation—Double Acting Plunger Pump  
       [0031]     Referring primarily to  FIGS. 1, 4  and  7 , the operation of the fluid handling pump when configured as a plunger pump will next be described.  
         [0032]     As the electric motor  12  drives the eccentric  66 , the ball bearing set  72  carried by the nose  70  of the eccentric will impart reciprocating linear motion to the shuttle member  74  by virtue of the engagement of the bearing&#39;s outer race  78  with the shoulders  80  and  82  of the shuttle member. This, in turn, will impart rectilinear reciprocating movement of the plungers  92  and  94 . Assuming that the pipe  24  is the low pressure inlet manifold of the pump, that pipe  26  is the high pressure outlet manifold and that one end of each of the pipes is capped, during a suction stroke of the plunger, i.e., when the plunger is moving toward the central axis of the pump, the fluid to be pumped will be drawn through the poppet valve  104  into the chamber  114 . Now, when the plunger begins its compression stroke, i.e., moves toward the valve assembly, the poppet valve  104  will seat while the poppet valve  106  is forced open against its spring, allowing the fluid in the chamber  114  to be forced out, under pressure, through the uncapped outlet port  32  or  34  of the pipe  26 . Because of the push/pull action of the pistons  92  and  94 , one complete revolution of the eccentric  66  will result in two suction strokes and two pressure strokes such that the high pressure fluid leaving the high pressure outlet will be somewhat less pulsatile than if only a single plunger is involved.  
       Diaphragm Pump Configuration  
       [0033]     Referring next to  FIGS. 5 and 10 , there are shown a cross-sectional view through the fluid handling pump and an exploded view thereof when configured as a diaphragm pump. It will be recognized that many of the parts used in implementing the diaphragm pump are the same as those used in implementing the plunger pump. For example, the pump body halves  16  and  18  are identical to one another and are the same as are used in the plunger pump of  FIG. 4 . The motor  12  may be the same as are the eccentric  66 , the bearing  72 , the shuttle  74 , the connecting rods  88  and  90 . Also, the poppet valves employed may be identical, although the tubular bodies  102 ′ and  102 ″ ( FIG. 8 ) are slightly different in that the frustoconical portion  114 ′ is provided with a groove  124  for receiving an annular rib  126  that projects from one side surface of an elastomeric diaphragm  128 / 129  proximate its periphery. A clamping ring, as at  130 , is designed to fit within the arcuate recess  46  formed in the pump body (halves)  16 ,  18  and it engages an annular rib  132  formed on the side of the diaphragm member  128  that is opposite from the rib  126 . It can be seen, then, that the diaphragm  128  is captured only proximate a peripheral edge portion thereof and the remaining portion of the diaphragm are free to flex or distort as the connecting rods reciprocate.  
         [0034]     Shoulder bolts comprising the connecting rods  88  and  90  each pass through a central aperture formed in the respective diaphragms. When the threaded end is tightened into one of the stub portions  84  or  84 ′ of the shuttle  74 , it is held against an arcuate backing plate  133  that is captured between the diaphragm  128  or  129  and a tubular bushing  134  or  134 ′ designed to mate with the stub  84  or  84 ′ of the shuttle  74 . The bushings  134  and  134 ′ are preferably made of a carbon or bronze material to provide a low friction engagement with a surrounding stationary bushing  136  or  136 ′ that is captured in a groove formed in the pump body.  
         [0035]     The poppet valves that fit into the opposed ends of the tubular valve housing  102 ′ are substantially identical to the poppet valves  104  and  106  used in the plunger pump. Each includes an open cage structure  138  containing a spring  140 , preferably fabricated from stainless steel so as to resist corrosion and which cooperates with a poppet to normally urge that poppet against an annular seat formed in the cage structure. O-ring seals, as at  142 , prevent leakage between the tubular valve housing  102 ′ and the cage structure  138 . See  FIG. 8 .  
       Operation—Double-Acting Diaphragm Pump  
       [0036]     With reference primarily to  FIGS. 1, 5  and  8 , the operation of the fluid handling pump when configured as a double-acting diaphragm pump will next be described.  
         [0037]     As the electric motor  12  drives the eccentric  66 , the ball bearing set  72  carried by the nose  70  of the eccentric will impart reciprocating linear motion to the shuttle member  74  by virtue of the engagement of the bearing&#39;s outer race with the shoulders  80  and  82  of the shuttle member. This, in turn, will impart rectilinear reciprocating movement of the connecting rods  88  and  90  within their guide sleeves  134 .  
         [0038]     Assuming again that the pipe  24  is the low pressure inlet side of the pump, that pipe  26  is the high pressure outlet side and that one end of each of the pipes is appropriately capped, as one of the connecting rods  88  or  90  moves toward the pump&#39;s center, a negative pressure is developed within its associated valve body  102 ′ causing the inlet poppet valve to open, allowing the fluid to be pumped to fill the chamber  114  of the valve body  102 ′ or  102 ″. Now, as the motor shaft continues to rotate and the eccentric drives the diaphragm  128  or  128  into the frustoconical portion  115  of its associated valve casing, the liquid being pumped to flow through its discharge poppet valve into the discharge pipe  26  is forced at a high pressure. It will be appreciated that as the connecting rod  88  is moving to the left in  FIG. 5  to create a pressure stroke, the connecting rod  90  is moving its diaphragm  129  in a direction to create a suction stroke. Thus, as the liquid being pumped is filling the valve chamber  102 ′ of one of the valve assemblies, the liquid being pumped is being forced out of the high pressure discharge poppet of the other valve  102 ″.  
         [0039]     It can now be appreciated that the present invention provides an improved, double-acting, simplex plunger or diaphragm pump that is characterized by having a unique method of assembly involving all but a few of common parts and a structural pump body having internal recesses for retaining the necessary bushings and seals when the identically configured pump body halves are bolted together. The two pump body halves effectively “sandwich” and clamp into molded recesses two valve casings that are generally in the shape of a “T” fitting. The two opposing ends of the “T” fitting contain the inlet and outlet valves. These two valves are identical with only the orientation of the valve relative to the “T” housing changing, thus allowing the movement of the fluid through the chamber in only one direction. Each pump body half has two ports and a common connecting pipe or channel for connecting the two pumping chambers. Depending upon the valve orientation, the common connecting pipe becomes either a suction manifold or a discharge manifold. In that each identical pump body half has one such pipe or channel, there is then a suction and a discharge passage. The pump of the present invention can be readily converted from a piston pump to a diaphragm pump by merely replacing the tubular valve housings, and substituting a diaphragm for a plunger or vice versa while the remaining parts are common to both.  
         [0040]     This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself