US2390762A - Pump - Google Patents

Description

Patemed Dec. 11,1945

PUMP

Frank C. lVoelfer, Jr., Cincinnati, Ohio, assignor to The Cincinnati Ball Crank Company, Cincinnati, (hio, a corporation of Ohio Original application March 9, 1940, Serial No. 323,195. Divided and this application May 14, 1942, Serial No. 442,923

1 Claim.

This invention relates to pumping apparatus of the type adapted to lift substances, for example, grease, from containers. More particularly, the invention is directed to pumping means of the type incorporating a tube depending from a pump actuating unit and including a piston reciprocating in the cylinder or tube and raising the substance to a chamber or supply point from which it is delivered to the point of use. The present application is divisional of my application Serial No. 323,195, led March 9, 1940, entitled Pumps, now Patent No. 2,312,857, granted March 2, 1943.

It has been the object of the present inventor to provide an improved piston structure incorporating value means so arranged as to coact witha valve in the base of the tube to permit grease or the like to pass through the piston on its down stroke and to cause the piston to lift the grease on the up stro-ke with the valve in the piston effective for permitting idling of the piston if the volume of grease or the pressure in the chamber which is supplied reaches a predetermined maximum.,

It has been a further object of the present inventor to provi-de a piston including a valve of this type which is held shut at a uniform pressure as the piston moves upward in the delivery stroke `and which will therefore open at the proper time; that is, will have a uniform action. More specilically, it has been the object to move the piston upwardly through solid contact with the piston rod as opposed to spring contact. The valve is free to act independently of the upward piston actuating force.

It will be appreciated that it is impossible to deliver a fixed amount of grease upon each normal stroke of the lifting or low pressure pump, and that in time, the supply chamber will be oversupplied or undersupplied. If undersupplied, the

pump is inefhcient and wasteful, and if oversup` plied, the operativeness of the mechanism is seriously affected for it will stall. Realizing that the output of the lift pump cannot be uniform, the present inventor has provided means for creating a slight reserve supply of grease in the chamber adjacent the high pressure pump and at the same time, means for preventing too much accumulation. Since the space in which the low pressure pump is mounted is limited, the present inventor has provided that this last-named means may also function a-s the intake means for the low pressure pump. In the disclosed embodiment, means employed for this purpose is constituted by a valve which has a double function, either opening for intake purposes for the low pressure pump, or opening for bly-passing purposes in the event of an oversupply of grease'to the high pres' sure pump.

Other objects and certain advantages of the present invention will be more fully apparent from the following description of the drawing in which:

Figure 1 is a sectional view taken vertically 'through the center of the apparatus showing the details thereof, with the pumping mechanism in position to start upward in the grease delivery stroke. e

Figure 2 is a fragmentary sectional View of the lower` end of the tube containing the low pressure pump showing the pump piston descending with the valve thereof in intake or open position.

Figure 3 is a View taken similar to Figure 2 showing the low pressure pump piston moving upwardly in the delivery stroke. l

Generally speaking, the pump assembly comprises an air motor II, a low pressure large vo-lume pump I2, and a high pressure small volume pump or grease ejector i3.` The low pressure pump I 2 is disposed below the air motor and sucks grease, for example, fromv a container, and delivers it through a by-pass to the high pressure plunger above the air motor. The air motor and pump plungers are in alignment and interconnect so that they reciprocate together.

The low pressure pump I2 operates in an intake cylinder I4. The upper end of cylinder I4 is threaded as at i5 to be secured to and depend from the yair pump casing, shown generally at I6, which houses the air motor I I. The lower endv of cylinder IB is internally threaded to receive an intake cap I'I. An aperture I8in the'bottomv of the cap I'I provides an intake opening, A bridge I9, spanning the aperture I8, spaces the intake cap from the bottom of the grease drum so that the aperture I 8 cannot become closed. n

At its upper or inner side, the aperture I8 provides a seat for a check valve 2U. Valve 20 i5 generally disc-shaped havingv its under, peripheral edge beveled to insure `a proper seal when seated.

A plurality of guiding Afingers 2 I extend outwardly and upwardly from the upper face of the check valve 2Q parallel 'to and in slidable Contact with the inner face of the intake cap so that the Valve remains centered with respect to the port I8. A set screw 22, extending through the wall of the cap II, limits the upward movement of the check valve.

The pump I2 is connected to the air motor through a connecting rod 23 (Figure 1) 'Ihe piston 24 of the pump i2 is slidably supported on the rod 23 between two coil springs 25-2S. [Ascunterturned section 27 of the rod 23 provides a shoulder 28 which is engaged by the upper end of the spring 25. The lower end of the spring 25 is engaged fby the top of the piston.

The piston 24 comprises a head 29 which is slidably engaged around the counterturned section 27 of the rod 23. The head is similar to an inverted thimble in that an internal counterbore provides a chamber 30. A plurality of discharge passages 3| is bored through the head to open the chamber 30 to the upper side of the piston. The wall of chamber 30 is threaded at 32 to receive a tubular nipple 33 which has a radial flange 34 extending outwardly from its outer wall just below its threaded section. The flange 34 cooperates with the downwardly extended rim 35 of the inverted thimble-like head 29 to hold in .place a cup piston ring 35. The bottom flange of the cup piston ring is clamped between the rim Y 35 and the ange 34 when the nipple 33 is screwed tightly into the chamber 30.

A sleeve 38 is engaged over the rod `23 inside the chamber 30. Its outside diameter is smaller than the inside diameter of the tubular nipple 33, so that a passage 39 exists between the two. The sleeve 38 rests upon the head of a valve retainer sleeve 4|. When the piston is at rest, as shown in Figure l, the sleeve 38 has its upper end spaced slightly from the top of the chamber 35. 'Ihe valve retainer sleeve 4| is engaged around a counterturned portion 42 of the rod 23 and its head abuts the shoulder which is provided by the counterturned portion. b

A valve 43 is urged upwardly against the collar by the action of the spring 26 disposed around the bushing 4| under compression between the valve and a washer 44 which is held in place by a nut 45 threaded on the end of the rod 23. The nut also holds the bushing 4| tightly against the shoulder of the piston rod. 'I'he downwardly extended rim or edge of the tubular nipple 33 constitutes a seat which is engaged by the springurged valve 43.

The head of the pump assembly comprises: a cylinder block 46 which has a by-passage 47 and a cylinder bore 48 in which a piston 49 of the air motor reciprocates; a casing 50 which includes the high pressure pump |3; and a head which constitutes a guide for the piston 49.

The connecting rod 23 extends upwardly from the pump I2 coaxially with the cylinder |4, and enters the air motor cylinder 48 through a packing gland 52. 'I'he upper end of the rod 23 is threaded into a nut 53 which in turn is threaded into the lower face of the piston 49 of the air motor. The nut 53 has a radial ange 55 which engages a double cup gasket 56 and secures it between the flange 55 and the lower face of the piston 49. A metal ring 57 is interposed between the radial anges of the two cups to stiffen the l gasket 56.4

A counterturned shoulder in the upper end of the cylinder 48 seats a cup packing gland 59. The head 5| includes a flange 5D at its lower end which is bolted to the flange 58 of the cylinder block and holds the packing gland in place. The packing gland 59 provides a seal around the piston 49. The gasket 55 and packing gland 59 provide two chambers in the cylinder bore.

One pressure chamber 52, below the gasket 55, has an effective area equal to that of the cylinder bore minus the cross section of the rod 23. The other pressure chamber 63,- above the piston, has an eiective area equal to that of the cylinder boreminus the area of the piston.

The chamber 82, below the piston 49, has an inlet and exhaust which is controlled by a valve means (not shown), while chamber 63, above the piston ring, is under constant air pressure.

The downstroke of the piston 49 results due to the fact that the pressure is relieved below the piston and the normal head of pressure above the piston forces it down. Although the air pressures are the same on both sides, the upstroke or power movement occurs due to the larger area of contact on the bottom of the piston. Moreover, the air acting on this larger area produces the high pressure. The downstroke is a low pressure loading stroke.

The head 5| mounted on the top of the cylinder block, has an internal bore 65 into which the piston of the air motor extends when it is moved upwardly on its power stroke. The lower end of the casing 58 for the high pressure cylinder 67 depends into the internal bore 65. The piston 49 is tubular as at 68 except for its lower end so as to clear the casing.

The upper portion of casing 58 is fitted into a central bore 79 in the top of the head 5|. A counterturned portion of bore 79 provides a shoulder 72 which abuts a shoulder 73 on the casing to secure it against upward displacement. The upper end of the casing is threaded internally as at 74 to engage threads on the lower end of the grease supply head 7|. A hexagonal ilange 75, just above the threads on the head 7|, engages the top of the head 5| so that as the head 7l is threaded into the housing the shoulder 72 on the housing is drawn up against the shoulder 73 in the bore 7|), thus fixing the casing 58 in place.

' The outer wall of the cylinder 67, near its upper end, has a counterturned section which vprovides a shoulder 77. The cylinder is held in place by the nut 18 of a packing gland 79, at its lower end which nut is threaded into the casing 50. When the nut 78 is tightened, the shoulder 77 on cylinder 67 is forced against a shoulder 80, which is on the inside of the bore in the casing 55.

The high pressure plunger 3 extends axially from the center of the piston 49 and upwardly through the packing gland'79 into the bore of cylinder 67. The plunger is held in place by a head at its lower end which is engaged between the nut 53 and the piston 49.

A counterbored section 8| in the upper end of the bore of the casing 59 contains a valve member 82. A ball check valve 83 is loosely mounted in the lower portion of the valve member and closes against a seat 84 when moved upwardly. The ball is retained by a pin 85 which passes horizontally through the member 82 below the valve. The upper portion of the valve member is tubular and extends partially up into the bore .of the grease supply head 7|. A shoulder 87 on the valve member engages the lower edge of the head 7| and is forced downwardly against a shoulder 89 provided by the counterbore 8|. A plurality of intake ports 99 are provided around the mid-section of the valve member. The counterbore 8| is larger than the valve member so that a chamber 9| is provided around the intake ports 93. The grease delivery to the high pressure piston is through a pipe 92 from the bypass chamber 47 in the cylinder block. Pipe 92 is threaded into the casing 5| in a line with the plurality of intake ports 98. A port 93 in the casing 5|) between the pipe 92 and the ports 98, connect the two.

When the piston of the air motor moves upwardly, the low pressure grease pump |2 forces grease up through the cylinder I4 through the bypass and port 93 and through the ports 99 into the head. At the same time, the high pressure plunger is moving upwardly, and since the grease above it in the bore of the cylinder Gl is under greater pressure than the grease in the head, the ball check valve 83 remains closed'. The grease under high pressure is forced from the bore of cylinder tl into a bore S4 in the casing wall which is below the check valve and above the upper extremity of the plungers stroke. A nipple Q5, threaded into the bore 9d through the wall of head 5| comprises the outlet for the grease.

On the down stroke of the piston, the check valve 83 opens and grease is forced by the air above it in the head and by suction, past the valve 83 into the high pressure cylinder bore. At this time, the low pressure pump moves downwardly, opening as it moves (Figure 2), to allow grease to pass through it.

The nipple 95 extends from the head 5| and is engaged by a T 96 at its outer end. A bleeder valve assembly 9'! is threaded into the end of the T 95 opposite the nipple 95. prises a tube 98 having a valve seat which seats a valve 99 xed on a stem Illl. The section oi plunger Ioutwardly from the valve 39 is square and has threads at its four corners for engagement with internal threads in the tube at this point. A pin is fixed in the outer end of stem |09 to facilitate turning. When the collar 99 is unseated by unscrewing the stem, a passage is opened past the flat sides of the square end of the stem. This is provided so that any air that is in the system when the unit is set up can be released easily at this point.

The inner end of the stem beyond `the valve 99 is cone shaped to iit into a concavity in the square base |02 of a seat for a spring m3. The coil spring |03 extends to the other side of the T 96 and urges a ball check valve against a seat |94 in the inner end of the nipple 95. The other arm |65 of the T 9B is counterbored .to provide a seat |96 which seats a ball check |81. Ball The bleeder comr check valve |87 is urged against its seat by a spring |03. The other end of spring |33 is engaged by the inner end of a threaded secti-on |99 of a swivel coupling H0. Beyond the coupling ||0 an elbow fitting has the high pressure grease hose connected to it.

Description of operation In operating the pump, it is mounted in any one of several ways so as to disposeits tube or cylinder Ill in the grease drum. The pump intake |8 of the low pressure pump, is then disposed adjacent the bottom of the drum. The nozzle of the grease discharge hose is extended .to the point of use. Air is admitted through the air intake conduit and enters the pressure chambers 2-53 in the pump cylinder. The air is at the same pressure in both of the chambers. It forces the pump piston 49 upwardly due to the difference between the area of piston exposed in the lower chamber 62 and that exposed in the upper charnber 63. Therefore, the air in chamber 63 is never lost.

The piston 24 is moved upwardly by direct contact of the piston rod 23 with the sleeve 38 which in turn engages the piston (Figure 3). When the pist-on 49 reaches the end of its upstroke, the air control valve (not shown) is tripped through its mechanism and the lower chamber 52 is then open to the atmosphere. As the air motor piston moves up, the pistonl of the low pressure pump l2, is drawn up in the tube |4 and grease is lifted to the chamber Tl above the high pressure cylinder 61'. As the air motor piston moves up, it also moves the piston of the high pressure pump I3. The high pressure piston causes the valve 83 to close in the high pressure cylinder and the grease is forced out through the port 94. In other words, as the grease is being lifted under low pressure for supply purposes for the high pressure pump, the high pressure pump is delivering 'a high pressure charge.

In the event that there is too much grease in the tube I4 and the pressure above the high pressure cylinder becomes too great, the resistance to the upstroke of the piston will unseat the valve 43 against the pressure of the spring 26.

VThis occurs when the pressure in the grease is greater than the force of the spring 26 which holds the valve 43 in seated position. The result is then that the grease by-passes through the piston and the rest of the stroke is lost motion. The suction valve 29 at the base of the cylinder i4 will open to admit the grease as the piston is moving up.

Now as the air motor moves down, the valve 20 closes (see Figure 2) and the descending rod 23 carrying the low pressure piston slides through the low pressure piston assembly unseating the valve against the pressure of the spring 26. Thus, the grease is free to iiow through the piston into the tube above it. As the high pressure piston descends, the vacuum created by the retraction of the high pressure piston draws a supply of grease into the high pressure cylinder. The head is constantly filled with grease and this accumulated supply column of grease is always available just over the high pressure cylinder. Each time the high pressure piston delivers a charge of grease under high pressure, the low pressure system lifts a supply.

It is impossible to provide a constant supply on each stroke and the volume of grease in the supply chamber varies. In this arrangement, a safety arrangement is provided. Excessive amounts are by-passed and stalling (such as would occur if the Agrease became too tightly packed in the supply chamber) is prevented. The same valve which permits ffilling of the tube above the piston brings about this ley-passage of oversupply.

The chamber provided in the head 'H over the high pressure cylinder provides a space in which the grease may accumulate. This chamber is l.. referred to as an accumulating or charging chamber since it is just above the high pressure chamber. The moment the high pressure piston starts down, the grease moves into the high pressure cylinder, not only because of expansive pressure in the grease but because of the suction created by the movement of the high pressure piston. Thus, it is provided that the high pressure cylinder is immediately completely filled with grease and the discharge stroke is entirely effective.

It will be noted Ithat there is very little agitation of the grease. This, of course, is advantageous since churning vor `undue working of the grease back and forth in the pump tends to break through the body of the grease. As the low pressure piston moves down through the grease, the grease flows through it. As it moves up, the grease is elevated. If there is too much grease above the piston, the valve unseats and the grease is by-passed back below the piston. It will be noted that the grease which is by-passed, that is, the `grease directly below the piston, is

picked up on the next stroke so that no specific quantity of grease is agitated over and over again.

Having described my invention, I claim:

In a lubricant pump, a cylinder, a piston in said cylinder, a piston rod for reciprocating said piston in the cylinder, said piston rod slidably mounted through said piston, a valve slidably mounted on said piston rod, said piston including a seat on its underside adapted to be engaged by said valve, an abutment of the lower end of the piston rod, a coil spring disposed under compression between the valve and the abutment, a shoulder on the piston rod adapted to engage the amount.

FRANK C. WOELFER, JR.

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