US3653788A

US3653788A - Metering pump

Info

Publication number: US3653788A
Application number: US25890A
Authority: US
Inventors: Edward I Klein
Original assignee: V Mark Automation Ltd
Current assignee: V Mark Automation Ltd
Priority date: 1970-04-06
Filing date: 1970-04-06
Publication date: 1972-04-04
Anticipated expiration: 1989-04-04
Also published as: CA939194A

Abstract

A metering pump having a passageway in the pump body, an inlet and outlet connected to the passageway and a valve member slidable between the inlet and outlet to alternatively open and close them. A chamber, the volume of which is changed by movement of a piston in the chamber, is connected to the passageway intermediate the inlet and outlet. Movement of the piston causes pumping of predetermined amounts of fluid through the passageway, the movement of the piston controlled by the position of the valve member.

Description

United States Patent [151 3,653,788 Klein 1451 Apr. 4, 1972 54] METERING PUMP 290,370 11/1931 Italy ..417/508 [72] Inventor: Edward I. Klein, Montreal, Quebec, Primary Emmmer R0bertM walker Canada At!0rneyAlan Swabey [73] Assignee: V-Mark Automation Ltd., Montreal,

Quebec, Canada RACT 22 i 1970 A metering pump having a passageway in the pump body, an inlet and outlet connected to the passageway and a valve [21] PP N05 25,890 member slidable between the inlet and outlet to alternatively open and close them. A chamber,-the volume of which is 52 0.8. 01 ..417/508,417/568 changed by mvem'em 0f 3 dumb, is 5 1 Int. Cl ..F04b 7/02, F04b 39/08, F04b 21/02, nected to the passageway intermediate the inlet and Outlet- 1 F0413 39/10 Movement of the piston causes pumping of predetermined 58 Field of Search ..417/508, 507, 568,557 amounts of fluid through the p y. the movement of the piston controlled by the position of the valve member. [56] References Cited FOREIGN PATENTS OR APPLICATIONS Claims Drawing Figure 5 /l9( )4 Germany fi l 7[50 8 control 1 66 devlce 67 PATENTEDAPR M912 control device INVENTOR Edward I. KLEIN METERING PUMP BACKGROUND OF INVENTION 1. Field of the Invention This invention relates to an improved metering pump.

More particularly, the invention relates to an improved metering pump which is simple in construction yet capable of operating at high speed to dispense a predetermined amount of fluid repetitively. The improved metering pump is particularly adapted to deliver predetermined amounts of fluid containing particles such as ink.

2. Description of the Prior Art Many small volume pumps used for repetitively delivering an amount of fluid use a reciprocating piston. However, pumps of this type have difficulty in delivering the same amount of fluid on each piston stroke, particularly if the fluid is not supplied to the inlet of the pump under relatively high pressure. In many pumps of this type, the outlet and the inlet of the pump are controlled by spring-biased valve members, the valve members being opened or closed depending upon the conditions within the chamber of the pump as a result ,of piston movement. At high speed operation of the pump, the springs could flutter, thus changing the time the valves are opened or closed and thereby changing the amount of fluid dispensed from the pump. Also, when the operation of springloaded valve means are dependent upon conditions within the chamber, unless the fluid is supplied to the inlet of the chamber at a relatively constant high pressure, the conditions within the chamber may change due to variations in the amount of fluid taken in, thus changing the timing of the operation of the valve means and again changing the amount of fluid dispensed by the pump.

In addition, in pumping fluids containing particles such as ink, the springs do not always exert sufficient pressure to positively seat the valve means in the inlet or outlet due to interference by the coloring particles in the ink. If colouring particles are located in the valve seat, they prevent the valve means from properly closing if the springs do not provide sufficient force to cause the valve means to cut through the particles. Thus, the seating of the valves means may not be positive, and this may again cause varied amounts of fluid to be dispensed from the pump.

In an attempt to partially overcome the above problems, attempts have been made to use the piston as a seal means for at least the inlet of the pump. However, accurate machining is required to obtain any sort of suitable seal, and this increases the cost of the pump. Even if an effective seal is obtained at the inlet, the outlet valve is still usually spring loaded resulting in the same problems previously discussed.

SUMMARY OF THE INVENTION The pump of the present invention is designed to overcome the above disadvantages. The pump is particularly adapted to be capable, even at high speed operation, to positively deliver predetermined amounts of fluid, particularly ink, more accurately than known pumps while being less expensive to manufacture. The pump is particularly suited for delivering accurate amounts of fluid regardless of the manner in which the fluid is supplied to the inlet of the pump. The fluid may be supplied under relatively high pressure, gravity feed or even vacuum. The pump is constructed to provide positive, independent sealing of the inlet and outlet prior to commencing the inlet or outlet stroke of the piston whereby more accurate amounts of fluid can be taken in and delivered from the pump.

The pump is constructed to avoid possible interference of the valve means by particles carried in the fluid by using a positive seating valve. The pump includes means for automatically repetitively dispensing a predetermined amount of ink at high speeds whereby it is useful for filling pens or cartridges with ink at assembly line speeds. The pump further includes means for easily adjusting the amount of fluid to be dispensed.

The invention is particularly directed toward a metering pump having a body with a passageway in the body. A fluid inlet and fluid outlet are connected to the passageway. A valve member is mounted for reciprocal movement within the body. Means are provided to positively reciprocate the valve member between the inlet and the outlet to alternatively close and open the inlet and outlet. Means are also provided communicating with the passageway for moving fluid into the passageway through the inlet, while the inlet is open and the outlet is closed by the valve member, and for moving fluid out of the passageway while the inlet is closed and the outlet is open by the valve member.

The invention further includes means operated by the valve member moving means for controlling operation of the fluid moving means.

BRIEF DESCRIPTION OF THE DRAWING The invention will now befdescribed in detail having reference to the accompanying drawing which illustrates a preferred embodiment of the dispensing pump shown in crosssection.

DESCRIPTION OF THE PREFERRED EMBODIMENT The metering pump 1 comprises a body 3 having a passageway 5 within the body for receiving the fluid to be dispensed by the pump. A fluid inlet 7 and outlet 9 are provided on opposed end faces 11 and 13 of the pump body. The

. inlet and outlet communicate via

channels

15, 16 with the passageway 5 respectively. If desired, fittings 17, 18 can be threadably connected to the inlet and outlet, each fitting having a through bore 19, 20 to communicate with

channels

15, 16 respectively. Means are provided in the fittings 17, 18 to permit connection of fluid inlet and outlet lines 21, 23 thereto.

Movable valve means 25 are provided within the body of the pump for cooperating with seats in the inlet and outlet to open or close the inlet and outlet thereby controlling the flow of fluid to and from the passageway 5 from inlet and outlet lines 21, 23. The valve means 25, as shown in the drawing, preferably comprises a cylindrical valve rod 27, larger in diameter than the bores 19, 20, slidable'in a bore 29 formed in the body above the passageway 5 and aligned with the inlet 7 and outlet 9. The ends 31, 32 of the rod 27 preferably are conical but could also be rounded. The ends 31, 32 of the rod 27 slide into the bores 19, 20 until stopped by the

seats

33, 34 formed on the

ends

35, 36 of the fittings 17, 18. The mouth of the bores 19, 20 defined by the

seats

33, 34, presents a sharp edge which cooperates with the ends 31, 32 of the rod to cut through any particles in the fluid at the seats and thus provide positive closure of the inlet and outlet. The rod 27 floats to some extent in bore 29 and each end is thus self-centering to some degree with respect to the seats to ensure a better seal. The rod 27 is slightly shorter in length than the distance between the

valve seats

33, 34 on the inlet and the outlet so that when one end 31 of the rod closes the inlet 7, the opposite end 32 of the rod is spaced away from the outlet 9 permitting communication of the bore 20 in the outlet fitting with the passageway 5 via the channel 16.

Means are provided for positively reciprocating the valve rod 27 back and forth in the bore 29 to alternatively close and open the inlet 7 and the outlet 9. These means preferably include a lever 37 pivotably connected by a pin 39 to the pump body 3 and located in a slot 41 in the body opening into the bore 29. One end 42 of the lever 37 is forked to have arms 43 (one of which is shown) straddling the rod 27. Each arm has a notch 45 to receive a pin 47 on the side of the rod 27. The opposite end 48 of the lever is located outside the slot 41. Pivoting of the lever 37 back and forth about pivot pin 39 causes the rod 27, through its connection by the notches 45 and pins 47, to reciprocate back and forth in bore 29 in the body.

Means are provided for rocking the lever 37 back and forth about the pivot pin 39 to move the closure member 25. These means can comprise two

actuators

49, 51, one mounted on one extension 53 of the pump body, the other mounted on a second extension 55 of the pump body so that the

actuators

49, 51 face each other with the end 48 of the lever 37 extending from the pump body located between them. Each actuator can comprise a piston 57, mounted in a chamber 59 formed in the

extensions

53, 55. The piston 57 is biased by a spring 61 in a direction away from the lever 37. A pin 63 extends from the piston 57 in one direction through one end wall 65 of the extension defining the chamber. An inlet 67 is provided in the opposite end wall 69 of the chamber. A fitting (not shown) connects a hydraulic or

pneumatic line

71, 72 to each chamber. The

lines

71, 72 are connected to a hydraulic or pneumatic supply and control device 73. The

actuators

49, 51 operate alternatively so that first one pushes the lever 37 about its pivot 39 to one side and then the other pushes the lever back to the other side.

Means are provided in the pump for moving liquid through the pump from the inlet 7 into the passageway 5 and from the passageway 5 out through the outlet 9. These means comprise a chamber 73 in the pump body 3. The chamber 73 preferably extends transversely to the passageway 5 and is connected thereto by a port 75. A piston 77 is mounted in the chamber 73. The piston 77 is operated by a pneumatic or hydraulic cylinder 79 to move back and forth in the chamber. The piston 77 moves down away from port 75 after the rod 27 is positioned to close the outlet 9 and to open the inlet 7. This creates a vacuum in passageway 5 to draw in fluid from a fluid supply (not shown) through the inlet 7. After a required amount of fluid has been drawn into the passageway 5 and also into chamber 73 through port 75, the rod 27 is moved by the lever 37 to close the inlet 7 and open the outlet 9. The piston 77 then is moved toward the port 75 to force a required amount of fluid out of the chamber 73 and passageway 5 through the outlet 9. The amount of fluid drawn in and pumped out each cycle is determined by the stroke of the piston 77. The larger the stroke, the greater the amount of fluid which can be drawn in.

Means can be provided for automatically controlling the operation of the piston 77 in sequence with the reciprocable operation of the valve rod 27 opening and closing the inlet and outlet. These means can comprise any well-known type of sensor means 81, 83 located in the path of movement of the free end 48 of the lever 37. Each sensor means 81, 83 has a sensing

member

85, 86 movably mounted in the upper end of each

body extension

53, 55 and extending toward the lever. Each sensing

member

85, 86 can be spring biased toward the lever and operatively connected to the control means 73 through

lines

87, 88. The sensing means 81, 83 may be connected to the control means 73 by electrical, pneumatic or hydraulic means.

The operation of the metering pump will now be described. The pump has been primed and a start signal is delivered to the control means 73 by means not shown. The control device then operates actuator 51, causing its pin 63 to push the lever 37 clockwise, as viewed in the drawing, thus closing, through valve rod 27, the outlet 9 of the pump and opening the inlet 7. Actuator 49 is not operative at this time, and its pin 63 is withdrawn away from the lever through spring 61 allowing the lever to move. When the lever 37 is moved clockwise, it contacts sensor 81, which, through its line 87, signals the control device 73 to cause operation of the cylinder 79 through line 91 in a manner to move piston 77 down. The timing is such that piston 77 moves down only when valve rod 27 has moved to close outlet 9. The inlet 7 is now open, and as the piston 77 moves away from port 75, fluid is drawn into passageway 5 and chamber 73 from inlet line 21. At the end of the piston stroke, a sensor (not shown) can be triggered by the piston causing the control device 73 to actuate the actuator 49 and release actuator 51 thus causing pin 63 of actuator 49 to move the lever 37 counter-clockwise. This slides the valve rod 27 away from the outlet 9 toward the inlet 7 thus opening the outlet and closing the inlet. As the lever 37 moves counter-- clockwise, it contacts sensor 83 thus, through the control means 73 and line 93, causing the cylinder 79 to raise the piston 77 forcing fluid out of the passageway 5 and chamber 73 through the outlet 9 whichis now open. When the piston 77 reaches the end of its stroke adjacent port 75, a further sensor (not shown) can be triggered by the piston to signal the control device 73 to again operate actuator 51 to repeat the cycle.

The operation of the

actuators

49, 51 and piston 77 can be by pneumatic, hydraulic or electrical means. The control means 73 can be of any well-known type for pneumatic, hydraulic or electrical systems. While two sensing systems have been described, one system for sensing the position of lever 37 and the other for sensing the position of piston 77,

only one sensing system could be used, if desired. The one system could sense the position of the lever 37 through sensors 81, 83 and through suitable timing means in the control device, cause operation of the piston 77 through cylinder 79 at the proper time having regard to the position of rod 27.

It will be seen that the valve rod 27 is positively driven and held to close either inlet7 or outlet 9, even at high speed operation, by the

actuators

49, 51. No springs are necessary and sealing is positive, particularly when the valve rod'27- is self-centering as shown. Also, the inlet or outlet is positively closed or opened before, and not by, the piston intake or exhaust stroke. Thus, the pump can effectively operate to draw in and dispense accurate predetermined amounts of fluid regardless of whether the fluid is supplied to the inlet under relatively high pressure, gravity or vacuum. With the outlet positively closed and the inlet open, the piston 77 then provides excellent vacuum for drawing in a predetermined amount of fluid regardless of how it is supplied to the inlet. However, piston 77 is only operated after outlet 9 is closed through sensor 81.

1 claim:

1. A metering pump having a body, a fluid passageway in the body, a fluid inlet and a' fluid outlet connected to the passageway, a valve member mounted for reciprocal movement in the body, first means for moving said valve member to positively reciprocate it between the inlet and the outlet to alternatively close and open the inlet and the outlet, and second means communicating with the passageway, intermediate the inlet and the outlet, for moving fluid into the passageway through the inlet while the inlet is open and the outlet is closed by the valve member, and for moving fluid out of the passageway while the inlet is closed by the valve member and the outlet is open, said second means comprising a chamber, a port connecting one end of the chamber to the passageway, a piston in the chamber, and third means moving the piston toward and away from the port, whereby movement of the piston toward the port decreases the volume of the chamber to move fluid therefrom through the passageway and the outlet and movement of the piston away from the port enlarges the chamber to move fluid into it through the passageway and the inlet.

2. A pump as claimed in claim 1, wherein each of the inlet and outlet includes a valve seat, a bore in the valve seat, the valve member comprising a rod having a diameter greater than the diameter of the bore in the valve seat, one end of the rod centrally located with respect to the bore in the inlet valve seat and slidable therein until the rod abuts the inlet valve seat to close the inlet, the other end of the rod centrally located with respect to the bore in the outlet valve seat and slidable therein until the rod abuts the outlet valve seat to close the outlet.

3. A metering pump as claimed in claim 1, including means for adjusting the size of the chamber.

4. A metering pump having a body, a fluid passageway in the body, a fluid inlet and a fluid outlet connected to the passageway, a valve member mounted for reciprocal movement in the body, first means for moving said valve member to positively reciprocate it between the inlet and the outlet to alternatively close and open the inlet and the outlet, and second means communicating with the passageway, intermediate the inlet and the outlet, for moving fluid into the passageway through the inlet while the inlet is open and the outlet is closed by the valve member, and for moving fluid out of the passageway while the inlet is closed by the valve member and the outlet is open, said first means comprising a lever connected at one end to the valve member, the lever pivotably connected intermediate at its ends to the body, and fourth means cooperating with the other end of the lever to rock it about its pivot connection to the body, said fourth means including opposed actuator members positioned on either side of the other end of the lever, said actuator members spring biased in a direction away from the lever, and fifth means for selectively moving each actuator member toward the lever to move the lever thereby causing movement of the valve member.

5. A metering pump having a body, a fluid passageway in the body, a fluid inlet and a fluid outlet connected to the passageway, a valve member mounted for reciprocal movement in the body, first means for moving said valve member to positively reciprocate it between the inlet and the outlet to alternatively close and open the inlet and the outlet, and second means communicating with the passageway, intermediate the inlet and the outlet, for moving fluid into the passageway through the inlet while the inlet is open and the outlet is closed by the valve member, and for moving fluid out of the passageway while the inlet is closed by the valve member and the outlet is open, said first means comprising a lever connected at one end to the valve member, the lever pivotably connected intermediate at its ends to the body, fourth means cooperating with the other end of the lever to rock it about its pivot connection to the body and sixth means, operated by movement of the lever, for controlling operation of the second means moving fluid into and out of the passageway.

6. A pump as claimed in claim 5, wherein the sixth means for controlling the operation of the second means includes sensors positioned in the path of movement of the lever, movement of the lever in one direction to move the valve member to close the outlet, causing one of said sensors to operate the second means to draw fluid into the passageway after the outlet is closed, movement of the lever in the opposite direction to move the valve member to close the inlet causing the other sensor to operate the fluid moving means to move fluid out of the passageway after the inlet is closed.

7. A metering pump having a body, a fluid passageway in the body, a fluid inlet and a fluid outlet connected to the passageway, a valve member mounted for reciprocal movement in the body, first means for moving said valve member to positively reciprocate it between the inlet and the outlet to alternatively close and open the inlet and the outlet, second means communicating with the passageway intermediate the inlet and the outlet, for moving fluid into and out of the passageway through the inlet and outlet respectively, control means for controlling operation of the second means, and first actuating means for actuating said control means to operate said second means to move fluid into the passageway when the outlet is closed by the valve and to move fluid out of the passageway when the inlet is closed by the valve, said first actuating means including sensor means operated by the first means.

8. A metering pump as claimed in claim 7 wherein the second means comprises a chamber, at least one port connecting the chamber to the passageway intermediate the inlet and outlet, a piston in the chamber, means for moving the piston toward and away from the port, said control means connected to said piston moving means to control the movement of the piston.

9. A metering pump as claimed in claim 8, including means for adjusting the size of the chamber.

10. A metering pump as claimed in claim 7, wherein each of the inlet and outlet includes a valve seat, a bore in the valve seat, the valve member comprising a rod having a diameter greater than the diameter of the bore in the valve seat, one end of the rod centrally located with respect to the bore in the inlet valve seat and slidable therein until the rod abuts the inlet valve seat to close the inlet, the other end of the rod centrally located with respect to the bore in the outlet valve seat and slidable therein until the rod abuts the outlet valve seat to close the outlet.

11. A metering pump as claimed in claim 7, wherein the first means comprises a lever connected at one end to the valve member, .the lever pivotally connected intermediate its ends to the body, and second actuating means cooperating with the other end of the lever to rock it about its pivot connection to the body.

12. A metering pump as claimed in claim 11, wherein the second actuating means includes opposed actuator members positioned on either side of the other end of the lever, said actuator members spring biased in a direction away from the lever, and means for selectively moving each actuator member toward the lever thereby causing movement of the valve member.

Claims

1. A metering pump having a body, a fluid passageway in the body, a fluid inlet and a fluid outlet connected to the passageway, a valve member mounted for reciprocal movement in the body, first means for moving said valve member to positively reciprocate it between the inlet and the outlet to alternatively close and open the inlet and the outlet, and second means communicating with the passageway, intermediate the inlet and the outlet, for moving fluid into the passageway through the inlet while the inlet is open and the outlet is closed by the valve member, and for moving fluid out of the passageway while the inlet is closed by the valve member and the outlet is open, said second means comprising a chamber, a port connecting one end of the chamber to the passageway, a piston in the chamber, and third means moving the piston toward and away from the port, whereby movEment of the piston toward the port decreases the volume of the chamber to move fluid therefrom through the passageway and the outlet and movement of the piston away from the port enlarges the chamber to move fluid into it through the passageway and the inlet.

11. A metering pump as claimed in claim 7, wherein the first means comprises a lever connected at one end to the valve member, the lever pivotally connected intermediate its ends to the body, and second actuating means cooperating with the other end of the lever to rock it about its pivot connection to the body.