US3447468A - Metering pump - Google Patents

Description

June 3, 1969 w. E. KINNE METERING PUMP Filed Jan. 24. 1968 5,3 '5 m5 I72 I 2 332 3883K @601 300] 304 320 I96 *4 I0 208 91 g; 352 FIG.8 A 32a. FIG.II 324 33s 34s 44 364 324 332 348 Ir340 364 H INVENTOR u WALTER E.KINNE ATTORNEYS United States Patent 3,447,468 METERING PUMP Walter Earle Kinne, 4071 Jordan Road, Skaneateles, N.Y. 13152 Filed Jan. 24, 1968, Ser. No. 700,078 Int. Cl. F041) 7/06, 19/22, 49/00 U.S. Cl. 103-38 7 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention My invention relates to a pump, and more particularly to a metering pump for fluids. Even more particularly, my invention relates to a metering pump which effects ositive sealing of inlet and outlet ports.

Description of the prior art Metering pumps for high-pressure fluids that effect positive sealing of the inlet and outlet ports are known. In U.S. Patent No. 1,238,939, issued Sept. 4, 1917, for an Oil Pump, a metering pump is disclosed which consists of a cylinder having inlet and outlet ports, a piston adapted to reciprocate and rotate simultaneously in the cylinder and formed to provide a valve acting to alternately cover and uncover the ports as the piston is rotated. means for positively reciprocating the piston comprising an annular cam and abutments engaging with opposite faces of the cam, the a-butments being carried on the cylinder wall, one of said abutments being shiftable toward or away from the other abutment, and means exterior to the cylinder wall whereby the movable abutment may be shifted and operatively engaging the non-movable abutment. In short, the variable reciprocating motion is achieved by means of a cam attached to the rotating piston. The cam travels around between a stationary lug and a variable lug mounted on the cylinder wall. Adjustment of the distance between the lugs determines the amount of the reciprocating action of the piston, hence, the amount of fluid pumped. When the lugs are spaced apart a distance equivalent to the rotating cam path thickness, the cam will rotate in place without imparting any reciprocating action to the piston. This is so because the incoming fluid does not have a pressure associated with it which is appreciably above atmospheric. The means of obtaining the variable reciprocating motion is mechanically complicated and suffers from the difiiculties usually encountered with such systems, for example, the continuous mechanical shearing force developed on the surface of the cam and lugs as the cam rotates between the lugs.

Other conventional metering pumps utilize pistons with check valves, or piston-plus-diaphragm-head with check valves. These check-valve pumps have the diseadvantages that accuracy is lost to leakage by the check-valves, fluid is leaked even through the pump is shut off when inlet pressure exceeds discharge pressure, and appreciable pressure is required to seat and seal discharge check-valves, even when clean fluids are utilized. Peristaltic pumps (tube squeezers), which are used to pump slurries, will not operate effectively at high pressures and have a somewhat complicated design.

3,447,468 Patented June 3, 1969 SUMMARY OF THE INVENTION My invention is an improvement in a pump for the metering of fluids which is basically comprised of a cylinder having metered-fluid inlet and outlet ports, a piston, rotatably mounted in the cylinder, which is of suflicient length to cover the metered-fluid inlet and outlet ports for any positioning of the piston in the cylinder and containing a fluid-passage channel to provide valve means controlling the metered-fluid inlet and outlet ports upon rotation of the piston, means for rotating the piston in one direction, and means for adjustably controlling the length of the piston stroke. My improvement consists of providing driving-fluid inlet and outlet ports in the cylinder which are located at the end of the piston away from the metered-fluid inlet and outlet ports and which are covered by the piston for any positioning of it in the cylinder, and also providing the end of the piston near the drivingfluid inlet and outlet ports with channels for passage of the driving fiuid to form valve means to control the driving-fluid inlet and outlet ports upon rotation of the piston.

Thus, my invention utilizes driving-fluid means to impart a variable reciprocating action to the piston. My metering pump does not suffer from any of the mechanical complexities or failings of metering pumps which obtain a reciprocating piston action by means of a cam system such as the one described in U.S. Patent No. 1,238,939.

The metering pump of my invention can be used to pump slurries, even at extremely high pressures, and therefore the term fluid includes slurries. The metering pump is economical, simple in design, which allows low construction costs, and is capable of operating over very wide delivery ranges. There is positive sealing of inlet and outlet ports even in the presence of solids in the metered fluid, which, of course, eliminates the need for back-pressure valves. Also, metered fluids can be at any pressure without aflecting pump accuracy. The metering pump of my invention, in general, can pump fluids having pressures from below atmospheric pressure to several thousand pounds per square inch.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the basic principles of my invention will be obtained from the accompanying drawings in which:

FIGURE 1 is a longitudinal sectional View, cut away, of a preferred embodiment of the pump of my invention,

partially metering illustrating the suction stroke and shown in conjunction With a typical apparatus for controlling the rotation of the piston, and in this embodiment the piston (and cylinder) is of two different diameters;

FIGURE 2 is a cross-sectional view of the metering pump shown in FIGURE 1 taken along lines 2-2 and viewed in the direction of the arrows;

FIGURE 3 is a cross-sectional view of the metering pump shown in FIGURE 1 taken along lines 3--3 and viewed in the direction of the arrows;

FIGURE 4 is a side elevation view of another embodiment of the piston with the left-hand end of the piston partially cut away;

FIGURE 5 is an elevation view of the left-hand end of the piston shown in FIGURE 4 as viewed from the left-hand side of FIGURE 4;

FIGURE 6 is a side elevation view of another embodiment of the piston with the left-hand end of the piston partially cut away;

FIGURE 7 is an elevation view of the left-hand end of the piston shown in FIGURE 6 as viewed from the left-hand side of FIGURE 6;

FIGURE 8 is a cross-sectional view, partially cut away, of the metering pump illustrating the discharge stroke;

FIGURE 9 is a cross-sectional view of the metering pump shown in FIGURE 8 taken along lines 9 -9 and viewed in the direction of the arrows;

FIGURE 10 is a cross-sectional view of the metering pump shown in FIGURE 9 taken along lines 10-10 and viewed in the direction of the arrows;

FIGURE 11 is a longitudinal sectional view, partially cut away, of one of the operational modes of another embodiment of the metering pump which can be used where the metered fluid is under appreciable pressure (substantially more than that required at the pump discharge) and in which the piston (and cylinder) is of only one diameter; and

FIGURE 12 is a longitudinal sectional view, partially cut away, of another of the operationol modes of the metering pump shown in FIGURE 11.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIGURE 1, the metering pump in general is indicated by the numeral 100. Metering pump 100 consists of cylinder 104, the bore of which has a comparatively small diameter at the left-hand end of cylinder 104 and has a comparatively large diameter at the right-hand end. The small diameter portion of the central bore (hereinafter termed the bore) extends about one-half the length of cylinder 104. The left-hand end of the bore of cylinder 104 is capped by means of cap 108 which is attached by screw threads to cylinder 104 at 112. The narrow diameter portion of the bore is known as chamber 116 or the fluid pumping chamber. The right-hand end of the bore is capped by means of cap 120 which is screw-threadedly attached to cylinder 104 at 124. The wide diameter portion of the bore is known as chamber 128 or the driving chamber. Fluid inlet port 132 passes radially through the wall of cylinder 104 into chamber 116. Fluid discharge port 136 (also termed fluid exit port 136) passes radially from chamber 116 through the wall of cylinder 104 and is located diametrically across from port 132. Air inlet port 140 (also termed driving-fluid inlet port 140) passes radially through the wall of cylinder 10 4 into chamber 128 and is located on a plane that intersects both port 132 and the axis of the bore of cylinder 104. Air exit port 144 (also termed driving-fluid exit port 1 44) passes radially from chamber 128 through the wall of cylinder 104 and is located diametrically across from port 140. The preferred air pressure range useful in this embodiment of my invention is between about p.s.i. to about 900 p.s.i., provided that a pressure differential of about 15 p.s.i. is maintained over the metered-fluid discharge pressure. The various inlet and outlet ports are placed in the same axial plane for reasons of simplicity of construction and operating design. However, such alignment is not crucial or required for the operability of this invention.

Piston 148, located within the enclosed bore area, consists of a left-hand segment 152 which has a comparatively small diameter. FIGURE 1 illustrates piston 148 in the left-hand position. Left-hand or delivery (metered fluid) segment 152 runs about one-half of the length of piston 148 and has a clearance with the cylindrical wall portion of chamber 116 that provides a smooth running fit, yet is tight enough to contain the fluid. Fluid leakage along the piston can be minimized by the use of piston rings, O-rings, etc. The right-hand or driving (driving-fluid) segment 156 of piston 148 has a comparatively large diameter and has a clearance with the cylindrical wall portion of chamber 128 that provides a smooth running fit, yet is tight enough to contain the fluid. The overall length of piston 148 is less than the overall length of the enclosed bore area, which allows piston 148 to have a reciprocating capacity. The length of each segment and the overall length of piston 148, as shown below, are one factor in the amount of fluid that metering pump 100 will deliver. The reciprocating movement of piston 148 is restricted in its left-hand directional movements by lip 160, located at the interface between chambers 116 and 128, which restrains further movement in that direction of segment 156 of cylinder 104. The inlet and outlet ports for both chambers 116 and 128 are located so that they are covered by piston 148 at all times within the limits of its reciprocal movement. Drive shaft 164 is attached to the right-hand end of piston 148 and protrudes through passageway 168, which is located in cap 120. Drive shaft 164 is rotatably and slidably mounted in passageway 168 but the fit is snug to minimize leakage out of chamber 128. Stutfing box 165 (the stufling is represented as 166) can be placed around drive shaft 164 on the outside of cap to further minimize the leakage outward along drive shaft 164. Sprocket 172 is affixed on drive shaft 164. Drive shaft 164 is connected to electric timing motor 176 by means of chain 180 (or timing belt) which is lapped over sprocket 172 and sprocket 184, the latter being afflxed on drive shaft 188 of electric timing motor 176. Adjustable stop 192 allows simple stroke adjustment which permits easy automation. (In general, drive shaft 164 can be rotated by any electric timing motor by menas of suit-able sprockets and chains or timing belts, or their mechanical equivalents, provided that the arrangement for driving drive shaft 164 has sufficient flexibility in the system to allow drive shaft 164 to follow the reciprocating action of piston 148 to which it is attached.) The right-hand directional move ments of piston 148 are restricted by adjustable stop 192, which means a limitation, in a sense, of the piston movement on the suction stroke. Adjustable step 192 may be the tip of a threaded rod, where adjustment is made by turning the rod, the tip of a rod whose position is controlled 'by an air diaphragm or electric solenoid such as a conventional control-valve positioner, or any other adjustable mechanical device. Sprocket 184 is easily changed to impart different rotational speeds to piston 148, thereby very wide capacity ranges are easily and simply obtained for metering pump 100. Preferably, stop 192, which is mounted externally from metering pump 100, contacts the right-hand end of drive shaft 164. An adjustable stop can be provided, alternatively, at the lefthand end of piston 148 to limit piston movement on the discharge stroke, but this is a less desirable arrangement since it involves sealing an opening in the fluid-pumping end of metering pump 100 to prevent leakage.

Segment 152 of piston 148 is provided with a fluidpassage channel which extends from a point to the right of fluid inlet port 132 to the left-hand end of segment 152. The fluid-passage channel can be flat side 196 on the periphery of piston 148 (as shown in FIGURE 1), or longitudinal groove 200 on one side of piston 148 (as shown in FIGURES 4 and 5), or internal passageway 204 in piston 148 connected to the periphery by an axial opening. The fluid-passage channel, in each of the above variations, extends from the left-hand end of the piston to a point where it can coincide with the fluid inlet port 132 and discharge port 136 for all longitudinal positions of piston 148. Flat side 196 is termed fluid passage channel 196. Segment 156 of piston 148 is provided with an air passage channel similar to the one provided in segment 152, for example, see flat side 208 on the periphery of segment 156. Flat side 208 is termed air-return channel 208. Air-return channel 208 is normally aligned axially with the fluid-passage channel 200 for simplicity in construction and because air-inlet port is normally aligned axially with fluid-inlet port 132. Air-return channel 208 extends longitudinally from the interface between segment 152 and segment 156 in piston 148 where the diameters change, to a point where it can coincide with air-inlet port 140 and air-outlet port 144 for all longi tudinal positions of piston 148. Segment 156 of piston 148 also contains a second air passageway similar to flat side 208. This second air passageway is flat side 212 and is termed air-driving channel 212. Air-driving channel 212 extends from the right-hand end of segment 156 of piston 148 to a point where it coincides with air-inlet port 5 140 and air-outlet port 144 for all longitudinal positions of piston 148. Air-driving channel 212 is located diametrically across from air-return channel 208.

Fluid-inlet port 132 is connected by suitable piping or tubing to the fluid to be pumped and metered. This may be a liquid, a liquid-solid slurry, or a gas. It can be in a container at the same level as the pump, at a higher or lower level, or can be supplied from a system under considerable pressure. Compressed-air inlet port 140 is connected to a source of compressed air or other gas or fluid under pressure. The pressure required is dictated primarily by the discharge pressure required of the pumped fluid. No connection to air vent port 144 is required if air or other harmless gas is used. With steam or liquids under pressure, air vent 144 is piped to a suitable point for disposal or reuse.

In operation, timing motor 176 causes drive shaft 164 and piston 148 to begin rotating. As piston 148 rotates it reaches a position where air-return channel 208 faces air-inlet port 140. Compressed air flows into channel 208, forcing piston 148 towards the right. As piston 148 moves to the right, compressed air flows into the annular space portion of chamber 128 where segment 152 of piston 148 changes into segment 156. Air trapped at the right-hand end of chamber 128 is vented out since air-driving channel 212 faces air-outlet port 144. Simultaneously, fluidpassage channel 196 faces fluid-inlet port 132. As piston 148 moves toward the right-hand end of pump 100, fluid is drawn into the expanding annular space at the left-hand end of chamber 116. The distance that piston 148 moves to the right on the suction stroke is determined by the position of adjustable stop 192, thereby regulating the amount of fluid that is drawn into chamber 116. Piston 148 continues to rotate during and after the suction or fluidintake stroke.

When piston 148 has rotated approximately 180, airdriving channel 212 faces air-inlet port 140 and air-return channel 208 faces air-outlet port 144 (see FIGURE 8). Compressed air flows into the space at the right-hand end of chamber 128, forcing piston 148 to the left and forcing the air in the annular space at the left-hand end of chamber 128 to vent out air-outlet port 144. Simultaneously, fluid-passage channel 196 faces fluid-outlet port 136. The fluid is expelled through discharge port 136 from the diminishing space at the left-hand end of chamber 116 as piston 148 is forced to the left. Continued rotation of piston 148 results in suction (intake) and discharge strokes being repeated again and again at a frequency controlled by the timing motor speed and sprocket drive ratio. In this way, a predetermined amount of fluid can be delivered in a certain amount of time at predetermined intervals.

FIGURE 2 is a cross-sectional view of metering pump 100 illustrating the relationship of flat space 196 of segment 152, fluid inlet port 132 and fluid outlet port 136, when piston 148 is in the suction stroke position shown in FIGURE 1. With piston 148 in the same position, FIG- URE 3, which is another cross-sectional view of metering pump 100, illustrates the relationship of flat spaces 208 and 212 of segment 156, air-inlet port 140' and airoutlet port 144. FIGURE 9 is a cross-sectional view of metering pump 100 illustrating the relationship of the same parts mentioned in FIGURE 2, but with piston 148 in the discharge stroke position shown in FIGURE 8. FIGURE 10 is a cross-sectional view of metering pump 100 illustrating the same relationship of the same parts mentioned in FIGURE 3, but with piston 148 in the discharge stroke position.

Leakage along piston 148, especially the liquid-pumping end, may be minimized by the use of piston rings, O-rings, etc. Overpressure protection for the pumped fluid end can be provided by applying safety-relief devices to the compressed-air driving system; this is of great value when the pumped fluid is a highly corrosive material which would require exotic materials of construction in its relief system.

Piston 148 can be modified so that it is in effect two pistons (with or without different sized diameters) with a connecting shaft between the pistons.

Referring to FIGURE 11, which is another embodiment of my invention, the metering pump in general is indicated by the numeral 300. This embodiment can be used where the fluid is under appreciable pressure, that is, substantially more than that required at the pump discharge. In this case, the use of compressed air can be eliminated and the construction of the pump simplified in that a cylinder and piston of only one diameter is needed. The driving fluid comes from the same source as the fluid to be metered. The incoming pressurized fluid at one end forces the metered amount of fluid entrapped at the opposite end of the piston out through the discharge port. Rotation of the piston 180 reverses the roles of the two ends of the unit. Metering pump 300 consists of cylinder 304, the internal bore thereof being equi-diametered, cap 308 which is screw-threadedly attached to the left-hand end of cylinder 304 at 312, and cap 316 which is screwthreadedly attached at the right-hand end of cylinder 304 at 320. The left-hand end of the bore of cylinder 304 is known as chamber 324 and the right-hand end is chamber 328. Inlet port 332 passes radially through the wall of cylinder 304 into chamber 324. Exit port 336 passes radially from chamber 324 through the wall of cylinder 304 and is located diametrically across from port 332. Inlet port 340 passes radially through the wall of cylinder 304 into chamber 328 and is located on a plane that intersects both port 332 and the axis of the bore of cylinder 304. Exit port 344 passes radially from chamber 328 through the wall of cylinder 304 and is located diametrically across from port 340. The various inlet and exit ports are placed in the same axial plane for reasons of simplicity of construction and operating design. However, such alignment is not crucial or required for the operability of this invention.

Piston 348, located within the enclosed bore area of cylinder 304, has a clearance with the inner cylindrical wall portion of cylinder 304 that provides a smooth running fit, yet is tight enough to contain the fluid. FIG- URE 11 illustrates piston 348 in the left-hand position. The overall length of piston 348 is less than the overall length of the enclosed bore area of cylinder 304, which allows piston 348 to have a reciprocating capacity. The length of piston 348, as shown below, is one factor in the amount of fluid that metering pump 300 will deliver. The inlet and exit ports for both chambers 324 and 328 are located so that they are covered by piston 348 at all times within the limits of its reciprocal movement. Drive shaft 352 is attached to the right-hand end of piston 348 and protrudes through passageway 356, which is located in cap 316. Drive shaft 352 is rotatably and slidably mounted in passageway 356 but the fit is snug to minimize leakage out of chamber 328. A stuffing box can be placed around drive shaft 352 on the outside of cap 316 to further minimize the leakage outward along drive shaft 352. Drive shaft 352 is rotatably interconnected with an electric timing motor in a manner similar to that shown in FIGURE 1 for metering pump Piston 348 is provided with channel 360 which is a flat side on the periphery of piston 348 and extends from the left-hand end of piston 348 to a point where it can coincide with inlet port 332 and outlet port 336 for all longitudinal positions of piston 348. Piston 348 is further provided with channel 364 which is a flat side on the periphery of piston 348 and is located diametrically across from channel 360. Channel 364 extends from the righthand end of piston 348 to a point where it coincides with inlet port 340 and outlet port 344 for all longitudinal positions of piston 348.

Inlet ports 332 and 340 are connected by suitable pip- 7 ing or tubing to the fluid to be pumped and metered. The fluid to be delivered is under substantial pressure, substantially more than that required at the pump discharge. Outlet ports 336 and 344 are connected by suitable piping or tubing, if necessary, to the fluid delivery point.

In operation, the timing motor causes drive shaft 352 and piston 348 to begin rotating. A's piston 348 rotates, it reaches a position where channel 360 faces inlet port 332. High pressure fluid flows into channel 360, forcing piston 348 towards the right. As piston 348 moves to the right, high pressure fluid is, first, allowed to slightly depressurize by escape out exit port 344 since channel 364 faces exit port 344 in this position of piston 348, and, then, is forced out exit port 344. As piston 348 moves toward the right-hand end of pump 300, high pressure fluid enters the expanding annular space at the left-hand end of chamber 324. Piston 348 continues to rotate during this right-hand directional stroke of pump 300.

When piston 348 has rotated approximately 180, channel 360 faces exit port 336 and channel 364 faces inlet port 340 (see FIGURE 12). High pressure fluid flows into the space at the right-hand end of chamber 328 and subsequently flows on into chamber 328, forcing piston 348 to the left. Simultaneously, channel 360 faces exit port 336. The high pressure fluid is expelled from chamber 324 through exit port 336 from the diminishing space in chamber 324 as piston 348 is forced to the left. Continued rotation of piston 348 results in the pumping and filling strokes being repeated again and again at a frequency controlled by the timing motor speed and sprocket drive ratio. In this way, a predetermined amount of fluid can be delivered in a certain amount of time at predetermined intervals.

This embodiment of the metering pump of my invention can pump fluids under pressures up to several thousand p.s.i. where the pressure differential over the delivered fluid pressure is about 20 p.s.i.

As illustrated in FIGURE 11, piston 348 is free to longitudinally travel the length of the bore of metering pump 300. An adjustable stop can be placed in a position abutting the right-hand end of shaft 352, similar to the adjustable stop shown in FIGURE 1, which will cause the amount of fluid pumped to be regulated.

I claim:

1. In a pump for the metering of fluids which is comprised of a cylinder having metered-fluid inlet and outlet ports, a piston, rotatably mounted in the cylinder which is of sufficient length to cover the metered-fluid inlet and outlet ports for any positioning of the piston vin the cylinder and which piston contains a fluid-passage channel to provide valve means controlling the metered-fluid inlet and outlet ports upon rotation of the piston, means for rotating the piston in one direction, and means for adjustably controlling the length of the piston stroke, the improvement consisting of driving-fluid inlet and outlet ports in the cylinder located at the end of the piston away from the metered-fluid inlet and outlet ports and covered by said end of the piston for any positioning of it in the cylinder, and the end of the piston near the driving-fluid inlet and outlet ports containing fluid-passage channels forming valve means that control the driving-fluid inlet and outlet ports upon rotation of the piston.

2. The pump of claim 1 in which the interior of the cylinder consists of two segments, each having a dilferent diameter, and the piston consists of two segments, each having a different diameter, which correspond to the segments of the cylinder.

3. The pump of claim 1 wherein the rotating motion of the piston is produced by a timing motor connected to a shaft attached to the driving-fluid end of the piston.

4. The pump of claim 1 wherein the length of the piston stroke is controlled by an adjustable stop arranged to contact the end of the piston shaft at the end of the piston stroke.

5. The pump of claim 1 in which the interior of the cylinder is of uniform diameter and the piston is of corresponding uniform. diameter.

6. The pump of claim 5 wherein the rotating motion of the piston is produced by a timing motor connected to a shaft attached to the driving-fluid end of the piston.

7. The pump of claim 5 wherein the length of the piston stroke is controlled by an adjustable stop arranged. to contact the end of the piston shaft at the end of the piston stroke.

- References Cited UNITED STATES PATENTS 412,217 10/1899 Wheeler 91 233 763,133 6/1904 Wheeler 91 233 1,428,204 9/1922 Barnickle 103 38 X 1,999,881 4/1935 Lowe.

2,898,890 8/1959 Lynott 91 37s 2,702,510 2/1955 Dourte -1 103-1s7 3,230,892 1/1966 Burns 103-157 3,313,237 4/1967 Plato 103-157 HENRY F. RADUAZO, Primary Examiner.

U.S. C1.X.R.

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