Elevator control for inductor pump

An inductor pump system comprises a fluid activated ram, an inductor pump platen, a fluid activated motor and a fluid control. The inductor pump platen is driven by the fluid activated ram. The fluid activated motor is coupled to the platen. The fluid control comprises an inlet for receiving a source of pressurized fluid, a first circuit and a second circuit. The first and second circuits are configured to receive pressurized fluid from the inlet. The first circuit comprises a switching valve connected to the inlet; an actuator line connected to the ram and the switching valve; and a blow-off line connected to the inductor pump platen and the switching valve. The second circuit is connected to the inlet to receive pressurized fluid and to the motor.

BACKGROUND

The present invention relates generally to inductor pumps for pumping highly viscous fluid from containers. In particular, the present invention relates to elevator controls for lifting and lowering platens used to push the fluid from a drum or container.

Inductor pumps typically comprise a linear pneumatic ram that forces a pipe having a platen into a drum. The platen includes a central bore that leads to a passageway in the pipe. As the platen is lowered into the drum by the pneumatic ram, the highly viscous fluid is forced into the central bore and up the passageway. The fluid is pushed into a pneumatic pump that forces pressurized fluid through a hose into a dispensing device where an operator can dispense a metered amount of fluid into some other typically smaller container.

Compressed air for operating the pneumatic ram and the pneumatic pump is delivered to a control panel on the inductor pump from a compressor or some other source. A compressed air line from the control panel is connected to either the pneumatic ram or the pneumatic pump, depending on which sub-system is being operated. In order to lift the platen, the compressed air is connected to the pneumatic ram. An on/off valve on the control panel is opened to allow air into the actuator to lift the platen so that a container of fluid can be positioned under the platen. Sometimes it is necessary to manually open a vent in the platen to prevent a vacuum from forming in the container. The on/off valve is closed to allow the platen to descend into the container. With the platen in a container, the compressed air line is disconnected from the pneumatic actuator and connected to the pneumatic pump. The on/off valve then toggles operation of the pump to control dispensing of the fluid from the container. Quick disconnect couplings are used on the compressed air line to facilitate operation of the actuator and pump. However, operation of the inductor pump is slowed by having to wait for the container to fill through the vent and by having to switch the source of compressed air. There is, therefore, a need for a more expediently controlled inductor pump.

SUMMARY

The present invention is directed to inductor pump systems and fluid circuits for controlling inductor pump systems. In one embodiment, an inductor pump system comprises a fluid activated ram, an inductor pump platen, a fluid activated motor and a fluid control. The inductor pump platen is driven by the fluid activated ram. The fluid activated motor is coupled to the platen. The fluid control comprises an inlet for receiving a source of pressurized fluid, a first circuit and a second circuit. The first and second circuits are configured to receive pressurized fluid from the inlet. The first circuit comprises a switching valve connected to the inlet; an actuator line connected to the ram and the switching valve; and a blow-off line connected to the inductor pump platen and the switching valve. The second circuit is connected to the inlet and to the motor.

The present invention is also directed to methods of operating an inductor pump system. In one embodiment, the method comprises providing a source of pressurized fluid to a control module, opening a relieving valve to allow pressurized fluid to flow through a switching valve to an actuator to raise a platen out of a container, actuating the switching valve to direct fluid away from the actuator and to the container through the platen to pressurize the container, and toggling the switching valve to alternately route air from the switching valve to the container or to the actuator.

DETAILED DESCRIPTION

Ram16comprises pneumatic cylinder34in which piston36is disposed. As shown inFIG. 1, piston36is fully seated within cylinder34of ram16. Support bracket38is mounted to a top, exposed end of piston36. Air motor18is mounted to the top of support bracket38and is controlled by elevator air controls14, which are mounted to the front of support bracket38. Pressurized air from a separate source (not shown) is provided to inlet50of elevator air controls14. Air motor18receives a flow of pressurized air from elevator air controls14through line52A. Cylinder34receives a flow of pressurized air from elevator air controls14through line52B. Pump20is suspended from the bottom of support bracket38by pins46that connect to housing40. Drive shaft48extends from air motor18to connect with pump20. Ram pipe22connects to inlet42of pump20and a dispensing device (not shown) is connected to outlet44through a hose. Hub64of modular platen assembly12connects to ram pipe22and wiper ring assembly66connects to hub64using coupling ring76.

Container94(FIG. 1C), which holds a fluid or viscous material that is to be dispensed by system10, is stored on platform26so that container94is accessible to platen assembly12. Wheels28A and28B are mounted on axle29, which is connected to platform26. Platform26is maintained level by wheels28A and2813and kickstand30. However, by tipping cart24backwards on wheels28A and28B, such as by tilting ram16using handle32, cart24can be easily moved to different locations. Once at the desired location, a dispensing device connected to pump20at outlet44is used to meter fluid pressurized by system10. Specifically, modular platen assembly12is pushed by ram16to engage container94and push fluid into ram pipe22such that pump20can be operated by air motor18to dispense the fluid. Air controls14of the present invention are coupled to mounting plate63as discussed with reference toFIG. 2and are arranged to control fluid flow through a number of fluid lines that form various fluid circuits, as discussed with reference toFIG. 3.

In operation, ram16is used to lift support bracket38up and away from platform26such that an empty container94can be removed from platform26and a full container94can be positioned between platform26and modular platen assembly12. Specifically, with pressurized air delivered to inlet50, on/off valve56is closed to prevent air from entering line52A and air motor18, while relieving valve62is opened to direct air to ram16by allowing air to enter line52B, as is discussed in greater detail with reference toFIG. 4A. The pressurized air travels to the bottom of cylinder34through piston36and pushes piston36out of cylinder34, pushing support bracket36away from platform26. If needed, switching valve60is actuated to cut off air flow to line52B and to deliver air to platen assembly12through line52C to assist in movement of platen assembly12, as discussed in greater detail with reference toFIG. 4B. Subsequently, container94storing a viscous fluid is positioned on platform26below wiper ring assembly66. Relieving valve62is repositioned to stop providing pressurized air to cylinder34, allowing modular platen assembly12to fall into the container94, as can be seen inFIG. 1Cand discussed in greater detail with reference toFIG. 4C. Check valve53prevents flow of air from container94into switching valve60or cylinder34. Additionally, bleed stick68can be manually actuated to allow airflow into and out of container94through a vent in hub64. The speed of travel of piston36is controlled by the rate at which air is permitted to leave cylinder34at a relief orifice in relieving valve62. Additionally, the descent of modular platen assembly12can be paused by actuating switching valve60while relieving valve62is closed to prevent air in cylinder34from reaching the relief orifice in relieving valve62and leaving cylinder34, as discussed in greater detail with reference toFIG. 4D

On/off valve56is positioned to permit pressurized air to flow to air motor18, which causes air motor18to actuate drive shaft48, as discussed in greater detail with reference toFIG. 4E. Depending on the type of pump used, drive shaft48rotates or reciprocates to drive pump20. Pump20pressurizes the fluid provided by ram pipe22and distributes the pressurized fluid to outlet44whereby the dispensing device can be used to meter measured amounts of the fluid. As fluid from container94is consumed, modular platen assembly12falls to the bottom of container94.

Wiper ring assembly66of modular platen assembly12engages the side of container94to push the viscous fluid downward, which forces the fluid up into a central bore located in hub64such that the fluid travels into ram pipe22and to pump20. As modular platen assembly12descends into container94, wiper72deflects to engage the sidewalls of container94to seal and scrape against container94. Container94comprises many different configurations, such as the diameter of the sidewalls, the slope of the sidewalls, and the presence or not of ribbing, corrugations or other stiffening features in the sidewalls. Modular platen assembly12permits wiper ring assembly66and coupling ring76to be expediently removed from hub64without having to disassembly wiper72and spacer74. As such, other wiper ring assemblies with different spacer and wiper configurations can be quickly secured to hub64for use with various configurations of container94. Further description of modular platen assembly12is located in related U.S. Pat. No. 8,708,201 entitled “MODULAR PLATEN ASSEMBLY FOR INDUCTOR PUMP,” which is filed on the same day as this application and is incorporated herein by reference.

To remove modular platen assembly12from container94, the steps ofFIGS. 4A and 4Bare repeated. Specifically, relieving valve62is again positioned to allow pressurized air to flow into cylinder34, and switching valve60is toggled to alternatively direct air from elevator air controls14to line52C, which delivers pressurized air into container94through modular platen assembly12to prevent a vacuum from forming in container94and to help push wiper ring assembly66out of container94. Air controls14allow pressurized air to be delivered to ram16and container94such that actuation of platen assembly12is more easily accomplished, while also allowing pressurized air to be delivered to air motor18.

FIG. 2is a front view of elevator air controls14ofFIGS. 1A,1B, and1C showing pressure regulator54, on/off valve56(also known as first on/off valve56), pressure gauge58, switching valve60and relieving valve62(also known as second on/off valve62) positioned on mounting bracket63. Mounting bracket63comprises a metal plate mounted to support bracket38of ram16(FIGS. 1A,1B and1C) that is positioned for convenient use by an operator of system10. Pressurized air is introduced to air controls14at inlet50and the various components of controls14control distribution of the pressurized air to the components of system10. Mounting bracket63consolidates the location of controls for system10such that an operator need not move about system10to control its various components, such as air motor18and ram16.

Operation of air motor18is controlled with on/off valve56(also known as first on/off valve56), pressure regulator54and pressure gauge58. On/off valve56comprises a simple ball valve, as is known in the art, that opens and closes depending on the position of lever78. With lever78oriented vertically as shown inFIG. 2, the ball closes the valve such that pressurized air cannot flow through valve56. With lever78oriented horizontally, the ball opens the valve such that pressurized air flows through valve56to air motor18. Pressure regulator54comprises any conventional regulator valve as is known in the art. Pressure regulator54matches the pressurized air provided to air motor18with the level of pressurized air demand by air motor18. Pressure regulator54also prevents elevated pressures from reaching air motor18. An operator of system10can manually adjust pressure regulator54to control the speed of air motor18. Pressure gauge58comprises any pressure gauge as is known in the art and provides an indication of the pressure output of pressure regulator54to an operator of system10. Operation of air motor18is controlled by pressure regulator54and on/off valve56independent of operation of ram16.

Operation of ram16is controlled with switching valve60and relieving valve62. Specifically, relieving valve62controls flow of pressurized air to ram16and switching valve60indirectly determines both upward and downward movements of ram16as used in system10. Relieving valve62, also known as second on/off valve, comprises an on/off ball valve having a relief orifice, as is known in the art. Valve62opens and closes depending on the position of lever80. With lever80oriented vertically, the ball closes the valve such that pressurized air cannot flow from inlet50through valve62. However, with the ball closed, air is allowed to flow back into valve62from ram16(FIG. 1B) and out the relief orifice. With lever80oriented horizontally as shown inFIG. 2, the ball opens such that pressurized air flows through valve62to air switching valve60.

In the embodiment described, switching valve60comprises a 3-way, 2-position pushbutton valve. Such valves and their functional equivalents are known in the art. Switching valve60includes an inlet into which pressurized air from valve62is introduced and two outlets for distributing the air to ram cylinder34and platen assembly12(FIG. 1B). Pushbutton82toggles switching valve60between delivering air to ram cylinder34and platen assembly12. As such, various fluid lines are connected to the components of controls14to form a circuit for controlling air motor18, and a circuit for controlling ram cylinder34and platen assembly12, as is shown inFIG. 3.

Inlet50is adapted to couple to a source of pressurized air. Inlet line84carries the pressurized air to first circuit86and second circuit88. First circuit86and second circuit88operate independently of each other. In first circuit86, pressure regulator54, pressure gauge58, on/off valve56and air motor18are connected in series. Thus, pressurized air flows to air motor18when on/off valve56is open, with the volume being controlled by regulator54. Air motor18can be operated regardless of the state of second circuit88and without having to disconnect or reconnect any air inlet lines.

In second circuit88, relieving valve62and switching valve60are connected in series. Inlet line88A feeds relieving valve62. Pressure line88B feeds an inlet to switching valve60from an outlet of relieving valve62. Relief orifice90is positioned within relieving valve90between the inlet and outlet. Relief line92connects the outlet of relieving valve62with relief orifice90. Switching valve60includes two outlets, to which actuator line52B and blow-off line52C are connected. Actuator line52B connects directly to cylinder34of ram16. Pressurized air within cylinder34pushes piston36out of cylinder34, carrying platen assembly12with it. Blow-off line52C connects to platen assembly12and includes check valve53, which permits flow into platen assembly12and prevents flow out of platen assembly12. Air from blow-off line52C pressurizes container94, which is mounted on platform26(FIGS. lA and1B). Bleed stick68can be manually operated to relieve pressure within container94. An exemplary bleed stick mechanism is described in U.S. Pat. No. 6,675,991 to Johnson et al., which is assigned to Graco Minn. Inc. Platen assembly12pushes material from container94through ram pipe22to pump20, where it provides pressurized material for metering with dispenser96.

FIG. 4Ais a flow diagram showing air flow through the air lines and valves ofFIG. 3while platen assembly12is being lifted away from container94by ram16.FIG. 4Adepicts a state of system10when an empty container94needs to be removed from platen assembly12such that a new, full container94can be positioned under platen assembly12. On/off valve56is closed such that pressurized air from inlet50can travel through first circuit86only as far as regulator54and gauge58. As such, air motor18is not operating. In second circuit88, relieving valve62is open such that pressurized air from inlet50travels through relieving valve62and into switching valve60. Button82of switching valve60is not pressed and switching valve60is not actuated such that pressurized air flows through switching valve60to actuator line52B, but not to blow-off line52C. Air from actuator line52B enters cylinder34, pushing piston36upwards. Platen assembly12is thus moved upwards within container94. After platen assembly12traverses some distance within container94, a vacuum begins to form within container94impeding further upward movement of platen assembly12.

FIG. 4Bis a flow diagram showing air flow through the air lines and valves ofFIG. 3while container94is being pressurized through platen assembly12.FIG. 4Bdepicts a state of system10when it is desirable to eliminate a vacuum that has formed in container94. On/off valve56remains closed such that air motor18is off, and relieving valve62remains open such that air flow to switching valve60remains active. Button82of switching valve60is pushed, or actuated, such that airflow from pressure line88B is prevented from entering actuator line52B, but is permitted to enter blow-off line52C. The air passes through check valve53and platen assembly12and enters container94, thereby pressurizing the backside of platen assembly12and neutralizing the vacuum therein. After the vacuum has dissipated, pushbutton82can be released to return system10to the state ofFIG. 4Aso lifting of platen assembly12with ram16can be resumed. Pushbutton82is subsequently toggled to lift platen assembly12and to fill the vacuum within container94until platen assembly12is removed from container94. With platen assembly12elevated, the empty container94can be removed, a new container can be replaced and platen assembly12can be lowered into position. Platen assembly12can be held in place with piston36fully extended from cylinder34by leaving system10in the state ofFIG. 4A.

FIG. 4Cis a flow diagram showing air flow through the air lines and valves ofFIG. 3while platen assembly12is descending into container94.FIG. 4Cdepicts a state of system10when it is desirable to load a container full of material into system10. On/off valve56of first circuit86again remains closed such that air motor18is off. Also, pushbutton82of switching valve62is released and relieving valve62is closed such that pressurized air does not flow to switching valve62. With pushbutton82released, actuator line52B is connected to pressure line88B such that air from within cylinder34is allowed to pass into switching valve60. With switching valve60closed, air from pressure line88B can escape second circuit88through relief line92and relief orifice90. Thus, piston36is unimpeded in its descent into container94and is free to push material in container94through ram pipe22to pump20. Descent of piston36into container94can, however, be paused such that container94can be properly aligned with platen assembly12.

FIG. 4Dis a flow diagram showing air flow through the air lines and valves ofFIG. 3while descent of platen assembly12into container94is paused.FIG. 4Ddepicts a state of system10when it is desirable to align or realign container94with platen assembly12to prevent binding in the system. On/off valve56of first circuit86remains closed such that air motor18is off. Relieving valve62is also closed as inFIG. 4Csuch that pressurized fluid is prevented from flowing to switching valve60. Pushbutton82of switching valve60is again pressed such that connection of actuator line52B with pressure line88B is cut off. Thus, air is prevented from escaping cylinder34through switching valve60. The weight of piston36pressurized the air trapped within cylinder34, resisting any further descent of piston36. Thus piston36becomes locked in place. The position of container94can then be adjusted with platen assembly12at rest. With container94and platen assembly properly aligned, system10can be configured for distribution of material from container94using dispensing device96.

FIG. 4Eis a flow diagram showing air flow through the air lines and valves ofFIG. 3while platen assembly12is descending and pump20is activated.FIG. 4Edepicts a state of system10when it is desirable to distribute material using dispensing device96. Relieving valve62is closed as inFIG. 4Dsuch that pressurized fluid is prevented from flowing to ram16or platen assembly12through switching valve60. Pushbutton82is released such that air is allowed to escape cylinder34through relief orifice90as isFIG. 4C. Thus, platen assembly12is free to drop into container94to push material into ram pipe22. Material in pipe22is delivered to inlet42(FIG. 1A) of pump20. Pump20is actuated by air motor18, which is activated by pressurized air from first circuit86. Specifically, with on/off valve56open, pressurized air flows into air motor18. Using pressure gauge58as an indicator, an operator can adjust pressure regulator54to allow a desired amount of air through pressure line86B and valve56such that air motor18operates at a desired speed. Air motor18actuates shaft58to drive pump20, which draws in material from pipe22. Pump20pressurizes the material and distributes the material to hose98. Dispensing device96, which comprises any known device such as a spray gun or metering receives pressurized material from hose98and upon actuation by an operator, dispenses the material for a desired application or into a desired container.

Air controls14of the present invention permit an operator of inductor pump system10to operate both air motor18and ram16without having to reposition lines of pressurized air. For example, a pressurized air source does not need to be disconnected from cylinder34and reconnected to air motor18. Thus, ram16and air motor18can be operated independent of the state of the other component. Furthermore, ram16can be fully operated to lift, pause and drop platen assembly12. For example, pushbutton82of switching valve60allows for two-way flow of air from cylinder34so that platen assembly12can be lifted by actuating piston36or lowered by allowing piston36to fall into cylinder34. Switching valve60and check valve53allow for one-way flow of air into platen assembly12such that air can be introduced into container94to assist in raising platen assembly12from container12. Switching valve60can be actuated to lock air inside cylinder34pausing movement of piston36. Thus, operation of inductor pump system10is expedited, reducing set up times and speeding up operations relating system10.