Double action simplex plunger pump

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.

BACKGROUND OF THE INVENTION

I. Field of the Invention

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.

II. Discussion of the Prior Art

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.

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

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.

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.

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 PREFERRED EMBODIMENT

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.

Referring first toFIG. 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 numeral10and is shown as being attached to an electric drive motor12in a manner that will be described in greater detail herein below. The pump10includes a pump body14that comprises a lower body half16and an upper body half18, 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 halves16and18are joined together about a midline plane20by nut and bolt fasteners as at22that pass through aligned apertures formed through the thickness dimension of laterally extending flange portions23and25of the upper and lower pump body halves,18and16, respectively.

As seen inFIG. 1, the lower16and upper18body halves each include a tubular pipe member, with pipe member24forming a part of the lower body member16and tubular pipe26forming part of the upper pump body member18. Pipe member24has first and second ends28and30. Likewise, tubular pipe member26has first and second ends32and34. In use, either end28or30of the pipe member24may 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 member26may 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 pipes24and26threaded, flexibility is afforded for the external connection of a fluid supply hose and a high pressure output hose.

Further, and as will be explained in greater detail below, depending upon the orientation of valve assemblies within the pump body14either pipe member24or tubular pipe member26may serve as the low pressure manifold with the other functioning as the high pressure manifold.

Turning next toFIGS. 2 and 3, the internal constructional features of the upper and lower pump body halves16and18can be viewed. Each of the upper and lower pump body halves has a planar surface36and formed inwardly thereof proximate opposed ends are first and second transversely extending pockets38and40leading to a flat annular surface42at the base of the pocket. The open center of the surface42leads to a bore (not shown) formed through the wall of the pipe members24and26.

Located longitudinally inward of the pockets38and40are semicircular recesses44and46and centrally disposed between the two ends is a generally rectangular pocket48. The rear wall50of the pump body halves16and18each includes a semicircular opening52therein leading to the pocket48. The bottom surface54of the pocket48includes an arcuate groove56adjacent to the rear wall50and a longitudinal groove58of semicircular cross section approximately midway between the rear wall50and a front wall60.

Plunger Pump Configuration

Attention is next directed to the cross sectional view ofFIG. 4which shows the lower pump body half16when containing the internal parts for implementing a plunger pump. As can be seen, the semi circular opening52in the rear sidewall is designed to accept a cylindrical projection62formed on the front end of the drive motor12therethrough. The pump is joined to the motor by bolts, as at63. The motor shaft64extends into the rectangular pocket48and mounted thereon is an eccentric member66that is held in place on the shaft by a setscrew68. The eccentric66includes a centrally disposed cylindrical nose portion70that extends through the central opening of a ball bearing set72.

A generally cylindrical shuttle member74has a notch76formed therein into which the bearing set72is made to fit with outer race.78abutting the shoulders80and82defining the opposed ends of the notch72.

The shuttle member74includes cylindrical stubs84and86on opposed ends thereof and the stubs, in turn, include longitudinally extending threaded bores into which are screwed connecting rod members88and90. The connecting rod members may comprise shoulder bolts that pass through cylindrical, tubular plungers92and94that 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 members92and94are held in tight abutting relationship to the ends of the stubs84and86of the shuttle member74and O-rings, as at96, serve as a seal to prevent fluid leaking along the interface between the connecting rods88and90and their respective plungers92and94from reaching the desired dry portions of the pump assembly including the rectangular pocket49and the component parts located there.

Next, turning momentarily toFIGS. 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 numeral100and includes a tubular valve casing102supporting an inlet poppet valve104and an outlet poppet valve106in spaced apart relation in the opposed end portions108and110of the tubular casing102. The5poppet 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 casing102of the valve assembly100includes a central opening112leading to an internal chamber114. A somewhat frustoconically-shaped flange115is integrally molded with the tubular body102and it is adapted to fit into either of the recesses44or46of the pump body16such that the tubular valve casing occupies one of the pockets38and40. O-ring seals, as at116and118, cooperate with the annular surfaces42formed in the pockets38and40to provide sealing therebetween.

As seen inFIGS. 4 and 7, a smooth carbon guide sleeve120is captured within a cylindrical tubular retainer122which fits into the central opening112of the valve casing and the inner end of the retainer122abuts a washer124that is used to hold an elastomeric cup seal126. As seen inFIG. 4, the plunger92passes through the carbon guide sleeve120and cooperates with the cup seal126to preclude fluid flow along the OD of the plunger92. The plunger94has an identical guide and seal arrangement. The exploded view ofFIG. 9will aid the reader in understanding the overall construction manner in which the plunger pump is assembled.

Referring primarily toFIGS. 1,4and7, the operation of the fluid handling pump when configured as a plunger pump will next be described.

As the electric motor12drives the eccentric66, the ball bearing set72carried by the nose70of the eccentric will impart reciprocating linear motion to the shuttle member74by virtue of the engagement of the bearing's outer race78with the shoulders80and82of the shuttle member. This, in turn, will impart rectilinear reciprocating movement of the plungers92and94. Assuming that the pipe24is the low pressure inlet manifold of the pump, that pipe26is 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 valve104into the chamber114. Now, when the plunger begins its compression stroke, i.e., moves toward the valve assembly, the poppet valve104will seat while the poppet valve106is forced open against its spring, allowing the fluid in the chamber114to be forced out, under pressure, through the uncapped outlet port32or34of the pipe26. Because of the push/pull action of the pistons92and94, one complete revolution of the eccentric66will 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

Referring next toFIGS. 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 halves16and18are identical to one another and are the same as are used in the plunger pump ofFIG. 4. The motor12may be the same as are the eccentric66, the bearing72, the shuttle74, the connecting rods88and90. Also, the poppet valves employed may be identical, although the tubular bodies102′ and102″ (FIG. 8) are slightly different in that the frustoconical portion114′ is provided with a groove124for receiving an annular rib126that projects from one side surface of an elastomeric diaphragm128/129proximate its periphery. A clamping ring, as at130, is designed to fit within the arcuate recess46formed in the pump body (halves)16,18and it engages an annular rib132formed on the side of the diaphragm member128that is opposite from the rib126. It can be seen, then, that the diaphragm128is 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.

Shoulder bolts comprising the connecting rods88and90each pass through a central aperture formed in the respective diaphragms. When the threaded end is tightened into one of the stub portions84or84′ of the shuttle74, it is held against an arcuate backing plate133that is captured between the diaphragm128or129and a tubular bushing134or134′ designed to mate with the stub84or84′ of the shuttle74. The bushings134and134′ are preferably made of a carbon or bronze material to provide a low friction engagement with a surrounding stationary bushing136or136′ that is captured in a groove formed in the pump body.

The poppet valves that fit into the opposed ends of the tubular valve housing102′ are substantially identical to the poppet valves104and106used in the plunger pump. Each includes an open cage structure138containing a spring140, 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 at142, prevent leakage between the tubular valve housing102′ and the cage structure138. SeeFIG. 8.

With reference primarily toFIGS. 1,5and8, the operation of the fluid handling pump when configured as a double-acting diaphragm pump will next be described.

As the electric motor12drives the eccentric66, the ball bearing set72carried by the nose70of the eccentric will impart reciprocating linear motion to the shuttle member74by virtue of the engagement of the bearing's outer race with the shoulders80and82of the shuttle member. This, in turn, will impart rectilinear reciprocating movement of the connecting rods88and90within their guide sleeves134.

Assuming again that the pipe24is the low pressure inlet side of the pump, that pipe26is the high pressure outlet side and that one end of each of the pipes is appropriately capped, as one of the connecting rods88or90moves toward the pump's center, a negative pressure is developed within its associated valve body102′ causing the inlet poppet valve to open, allowing the fluid to be pumped to fill the chamber114of the valve body102′ or102″. Now, as the motor shaft continues to rotate and the eccentric drives the diaphragm128or128into the frustoconical portion115of its associated valve casing, the liquid being pumped to flow through its discharge poppet valve into the discharge pipe26is forced at a high pressure. It will be appreciated that as the connecting rod88is moving to the left inFIG. 5to create a pressure stroke, the connecting rod90is moving its diaphragm129in a direction to create a suction stroke. Thus, as the liquid being pumped is filling the valve chamber102′ of one of the valve assemblies, the liquid being pumped is being forced out of the high pressure discharge poppet of the other valve102″.

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.