Reciprocating pump with electronically monitored air valve and piston

Abstract

An air operated pump 10 uses a magnet 14 mounted in the valve cup 16 of the air motor 18 and two reed sensors 20 mounted in the valve cover 22 to monitor the speed and position of the valve 16. A solenoid 24 is mounted on the valve cover 22 and can be commanded to extend a plunger 26 into the valve cup 16 to stop valve movement and therefore the pump from running away A magnetoresistive sensor 34 is located in the center of the air motor 18 to precisely monitor the piston 36 position and with air valve sensors 20 provides the input necessary for precise control and diagnostics of the pump 10 and makes it suitable for metering and plural component application.

Claims

1. An air operated reciprocating piston pump comprising: an air motor for driving the pump, the air motor having a piston; a sensor comprising a linear transducer that monitors position of the piston in the air motor; an air valve that controls flow of air to opposite sides of the piston of the air motor, the air valve including: a valve cup; a valve cover; a magnet mounted in said valve cup of said air motor; first and second reed sensors mounted in the valve cover to monitor the speed and position of the valve, wherein the first and second reed sensors and the magnet are located so as to detect when the air valve is at an extreme position of each stroke or in transition between extreme positions, or both; a solenoid having a plunger and being mounted on said valve cover, said solenoid being capable of extending said plunger into said valve cup to stop valve movement and therefore the pump from running away; a controller that calculates a rate at which the air motor is running based on opening and closing of the first and second reed sensors activated by varying positions of the air valve, determines whether the air motor is in a runaway condition, and activates the solenoid to extend the plunger into the valve cup to stop valve movement and thereby stop the air motor when the controller determines that a runaway condition is present.

2. The air operated reciprocating piston pump of claim 1 further comprising a user interface responsive to the controller to allow the display of various parameters based upon monitoring of the reed sensors by the controller.

3. The air operated pump reciprocating piston of claim 2 wherein said parameters include at least one of cycle rate, flow rate, total cycles and diagnostic errors.

4. The air operated reciprocating piston pump of claim 1 wherein said linear transducer comprises a magnetoresistive sensor.

5. The air operated reciprocating piston pump of claim 4 wherein said controller utilizes information from said linear transducer for feedback to an air regulator that modulates air pressure input to the air motor.

6. The air operated reciprocating piston pump of claim 5 wherein said controller controls pump flow volume based upon information from the linear transducer by controlling shaft displacement and velocity.

7. The air operated reciprocating piston pump of claim 5 wherein said controller controls pump flow rate based upon information from the linear transducer by controlling shaft displacement and velocity.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows a cross-section of the air valve as part of the instant invention showing the magnets and reed switches.

(2) FIG. 2 shows a detail of the FIG. 1 cross-section of the air valve as part of the instant invention.

(3) FIG. 3 shows a cross-section (opposite that of FIG. 1) of the air valve as part of the instant invention showing the solenoid.

(4) FIG. 4 shows a view of a pump incorporating the instant invention.

(5) FIG. 5 shows a detail of the user interface of the instant invention.

(6) FIG. 6 shows the diagnostic codes which may be obtained by sensing the sir valve.

(7) FIG. 7 shows the piston and magnetoresistive sensor.

(8) FIG. 8 shows a block diagram of the pump of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

(9) In an air-operated reciprocating piston pump 10, the controller 12 uses a magnet 14 mounted in the valve cup 16 of the air motor 18 and two reed sensors 20 mounted in the valve cover 22 to monitor the speed and position of the valve 16. A solenoid 24 is mounted on the valve cover 22 and can be commanded to extend a plunger 26 into the valve cup 16 to stop valve movement and therefore the pump 10 from running away (typically caused by the fluid supply being empty or the hose of other supply conduit having a leak/rupture.) The user interface 28 comprises an LCD display 30 and buttons 32 to set up and control the pump 10. The display 30 can be toggled to display cycle rate, flow rate (in various units), total cycles and diagnostic errors. Setup parameters can include fluid units (quarts, liters, etc.) and the runaway set point.

(10) The reed switches 20 and magnets 14 are located so as to detect when the air valve 16 is at the extreme position of each stroke or in transition or both. The controller 12 calculates the rate at which the motor 18 is running by counting the opening and closing of the reed switches 20 activated by the varying positions of the air valve 16. The controller 12 then compares that rate to a pre-programmed value to determine if the air motor 18 is in a runaway condition. The that condition is present, the controller 12 activates the solenoid 24 preventing changeover which stops the motor 18. This acts to prevent spilled fluid and/or pump damage.

(11) A magnetoresistive sensor 34 is located in the center of the air motor 18 to precisely monitor the piston 36 position. The data from this sensor 34 in conjunction with that from the air valve sensors 20 provides the input necessary for precise control and diagnostics of the pump 10 and makes it suitable for metering and plural component application.

(12) The controller 12 of the instant invention seen in FIG. 8 can use information from the linear transducer for feedback to the air pressure (or fluid pressure if hydraulic) to control the flow volume and rate by controlling shaft displacement and velocity. Such can be done via an air pressure regulator 40 which modulates a supply 42 of pressurized air (or hydraulic fluid). This feedback may be used in either a simple meter dispense system with one fluid or a two (or more) component system where the feedback is used to maintain flow, pressure and ratio.

(13) It is contemplated that various changes and modifications may be made to the pump control without departing from the spirit and scope of the invention as defined by the following claims.