Method and apparatus for dispensing liquids and solids
First Claim
1. A dispensing system comprisinga plurality of progressive cavity pumps;
- a mixer in communication with the progressive cavity pumps;
a conduit having an outlet, the conduit being in pressure flow communication between the mixer and the outlet;
a pressure sensor in communication with the pressure flow to the outlet;
a plurality of motors, the motors being coupled to the progressive cavity pumps, respectively;
a controller in signal communication with the pressure sensor and with the motors, the controller being responsive to pressure input from the pressure sensor to control the motors based on the pressure sensed by the pressure sensor and on the pressure sensed by the pressure sensor as a function of time.
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Accused Products
Abstract
A system for metering and dispensing single and plural component liquids and solids as described herein. The dispensing system has a microprocessor-based control system and progressive cavity pumps which provide a very accurate control of component ratios, shot sizes, flow rates and dispense durations. The system has numerous feedback components for accurately controlling the pressure, flow rates, fluid levels and amounts of fluids dispensed. Where a valved nozzle is used, the pressure in the flow system is used to control the pumps rather than the valve. Such a system may be used as a sprayer with compressed air added. Drum rams are associated with the supply drums and the progressive cavity pumps may be placed on the drum ram. Maintenance of a steady state in the system is accomplished with back and forth movement of the pump, with compensation for pressure changes. Absolute rotational position of the pump can be monitored when a set pressure is maintained, to diagnose system conditions. A high flow system uses ball valves and a releasably coupled manifold. A mold charging system uses pressure to control the pumps which are cycled on and off to avoid overpressurizing the mold. The rate of pressure increase is used to control the rate of flow from the pumps as the mold approaches completion of the charge, again to avoid overpressurizing the mold. A signal controlled by a timer can indicate elapsed time as a warning that material within the mixer conduit is hardening to a condition such that flow cannot be reinitiated.
132 Citations
34 Claims
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1. A dispensing system comprising
a plurality of progressive cavity pumps; -
a mixer in communication with the progressive cavity pumps; a conduit having an outlet, the conduit being in pressure flow communication between the mixer and the outlet; a pressure sensor in communication with the pressure flow to the outlet; a plurality of motors, the motors being coupled to the progressive cavity pumps, respectively; a controller in signal communication with the pressure sensor and with the motors, the controller being responsive to pressure input from the pressure sensor to control the motors based on the pressure sensed by the pressure sensor and on the pressure sensed by the pressure sensor as a function of time. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for pressure dispensing with a mixture of materials from progressive cavity pumps driven by motors, respectively, through a conduit, comprising
driving the pumps; -
mixing the pumped materials; repeatedly sampling pressure of the mixed pumped materials; sending a signal from the controller to turn off the pumps when pressure of the mixed pump materials rises above a preselected high pressure; sending a signal from the controller to turn on the pumps when pressure of the mixed pump materials falls below a preselected low pressure; reducing the driving speed of the pumps when a rate of pressure increase of the mixed pump materials exceeds a preselected amount. - View Dependent Claims (8, 9)
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10. A dispensing system maintaining a target pressure during dispensing, comprising
a progressive cavity pump having an outlet; -
a motor coupled with the progressive cavity pump; a pump control system controlling the motor and including a preset target pressure; a pressure sensor in pressure communication with the pump outlet and in signal communication with the pump control system, pump speed being controlled as a function of the differential pressure between actual pressure of the pressure sensor and the preset target pressure by the pump control system. - View Dependent Claims (11, 12, 13, 14, 34)
- 14. The dispensing system of claim 10, the function being
- space="preserve" listing-type="equation">Q=G.sub.p ·
dP.sub.s +G.sub.i. (dP.sub.s +dP.sub.s-1)+G.sub.d ·
(dP.sub.s -dP.sub.s-1).
where Q is flow rate of the pump, Gp is the proportional gain, Gi is the integral gain, Gd is the derivative gain and dPs is the differential between the target pressure and the actual pressure with the subscript s denoting successive pressure samples. - space="preserve" listing-type="equation">Q=G.sub.p ·
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34. The dispensing system of claim 10 further comprising
a nozzle; a conduit in flow communication between the mixer and the nozzle.
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15. A method for maintaining a target pressure during dispensing using a pump control system, comprising
controlling the speed of a progressive cavity pump with the pump control system; -
repeatedly sensing pressure of the output of the pump; providing the sensed pressure to the pump control system; storing a target pressure in the pump control system; adjusting control of the progressive cavity pump with the pump control system as a function of the differential pressure between actual pressure of the pressure sensor and the preset target pressure. - View Dependent Claims (16)
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17. A method for maintaining a target pressure using a controller during the dispensing through a mixer of a mixture of materials from progressive cavity pumps driven by motors, respectively, comprising
repeatedly sensing pressure of the output of at least one of the pumps; -
providing representations of the repeatedly sensed pressure to the controller; storing a target pressure; driving the motors at proportional speeds; mixing the materials from the progressive cavity pumps; sending signals from the controller to adjust the proportional speeds of the motors as a function of the differential pressure between actual pressure of the pressure sensor and the preset target pressure. - View Dependent Claims (18, 19, 20)
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20. The method of claim 17 further comprising
sending a signal from the controller to turn off the pumps when pressure of the mixed pump materials rises above a preselected high pressure; sending a signal from the controller to turn on the pumps when pressure of the mixed pump materials falls below the target pressure.
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21. A method for maintaining a target pressure using a controller during the dispensing through a mixer and a valve controlled nozzle from the mixer of a mixture of materials from progressive cavity pumps driven by motors, respectively, comprising
repeatedly sensing pressure of the output of at least one of the pumps; -
providing representations of the repeatedly sensed pressure to a controller; storing a target pressure; driving the motors at proportional speeds; mixing the materials from the progressive cavity pumps; sending signals from the controller to adjust the proportional speeds of the motors as a function of the differential pressure between actual pressure of the pressure sensor and the preset target pressure; opening and closing the valve controlled nozzle independently of the sampled pressure. - View Dependent Claims (22, 23, 24)
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24. The method of claim 21 further comprising
selectively closing the valve; - stabilizing the pressure between the progressive cavity pumps and the valve with the valve closed, including in periodic cycles, in seriatim for each pump, measuring the sampled pressure a first time, rotating the progressive cavity pump a partial turn in a first direction, rotating the progressive cavity pump a partial turn in a second direction opposite to the first direction, measuring the sampled pressure a second time, and comparing the second measurement of the sampled pressure with the first measurement of the sampled pressure, the rotation of the progressive cavity pump a partial turn in the second direction including changing the amount of rotation in the second direction if the sampled pressure after rotation was different from the sampled pressure before rotation in the just prior cycle.
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25. A dispensing system maintaining a target pressure during dispensing, comprising
a plurality of progressive cavity pumps; -
a mixer in communication with the plurality of progressive cavity pumps; a plurality of motors, the motors being coupled with the progressive cavity pumps, respectively; a pump control system controlling the motors to drive the pumps at proportional speeds and including a preset target pressure; a pressure sensor in pressure communication with the output of at least one of the plurality of progressive cavity pumps and in signal communication with the pump control system, pump speeds being controlled as a function of the differential pressure between actual pressure of the pressure sensor and the preset target pressure by the pump control system. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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29. The dispensing system of claim 25 further comprising
a nozzle; a conduit in flow communication between the mixer and the nozzle.
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30. The dispensing system of claim 29 further comprising
a valve in the nozzle. -
31. The dispensing system of claim 29, the valve being controlled independently of the pump control system.
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32. The dispensing system of claim 31 further comprising
a valve in the nozzle. -
33. The dispensing system of claim 31, the valve being controlled independently of the pump control system.
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Specification