Flow Rate Accuracy of a Fluidic Delivery System
First Claim
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1. A valve assembly with variable flow rate of fluid delivery, comprising:
- a power supply;
charge pump circuitry powered by the power supply;
a piezoelectric actuator charged by the charge pump circuitry, the charge applied across the piezoelectric actuator reaching a predetermined voltage threshold over a predetermined rise time; and
a valve transitioning from a CLOSED state to an OPENED state when the charge applied across the piezoelectric actuator exceeds the predetermined voltage threshold;
the valve assembly having a duty cycle adaptable to vary the flow rate of the fluid delivered by the valve.
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Abstract
Improving the accuracy of the flow rate of a valve in a fluidic delivery device in which a desired flow rate may be achieved by varying the duty cycle of the valve. The flow rate of fluid delivery from the valve over its lifetime is stabilized by minimizing the voltage OPENING time of the valve to account for valve and piezoelectric actuator drift. Also, the valve OPENING time of one or more fluidic parameters that impact on the flow rate delivery by the valve and differ among fluidic delivery devices is compensated to optimize the flow rate accuracy.
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Citations
2 Claims
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1. A valve assembly with variable flow rate of fluid delivery, comprising:
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a power supply; charge pump circuitry powered by the power supply; a piezoelectric actuator charged by the charge pump circuitry, the charge applied across the piezoelectric actuator reaching a predetermined voltage threshold over a predetermined rise time; and a valve transitioning from a CLOSED state to an OPENED state when the charge applied across the piezoelectric actuator exceeds the predetermined voltage threshold;
the valve assembly having a duty cycle adaptable to vary the flow rate of the fluid delivered by the valve.
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2. A method for varying a flow rate of fluid delivery from a valve assembly including charge pump circuitry powered by a power supply for applying a charge across a piezoelectric actuator, and a valve transitioning from a CLOSED state to an OPENED state when the charge applied across the piezoelectric actuator exceeds a predetermined voltage threshold, comprising the step of:
varying the flow rate of the fluid delivery from the valve by adjusting a duty cycle of the valve.
Specification