Precision flow control system
First Claim
1. A low flow rate precision flow controller system comprising:
- (a) a plurality of continuously variable pressure fluid supplies delivering a plurality of fluids;
(b) a single fluid outlet being in fluid communication with the plurality of fluid supplies, the plurality of fluids being mixed before exiting through the outlet;
(c) a plurality of pressure sources corresponding to the plurality of fluids, each pressure source applying pressure to each fluid;
(d) a plurality of capillary tube thermal mass flowmeters, each flowmeter detecting the flow rate of each fluid of the corresponding plurality of fluids; and
(e) a controller for electronic flow control in communication with the respective flowmeter and the respective pressure source, wherein the controller compares the respective measured flow rate to a respective desired flow rate and adjusts the respective pressure source so that the respective fluid flows at the respective desired flow rate, wherein the fluids flow out of the fluid outlet at a flow rate of less than approximately 100 microliters/minute.
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Accused Products
Abstract
A precision flow controller is capable of providing a flow rate less than 100 microliters/minute and varying the flow rate in a prescribed manner that is both predictable and reproducible where the accuracy and precision of the flowrate is less than 5% of the flow rate. A plurality of variable pressure fluid supplies pump fluid through a single outlet. Flowmeters measure the flow rates and a controller compares the flow rates to desired flowrates and, if necessary, adjusts the plurality of variable pressure fluid supplies so that the variable pressure fluid supplies pump fluid at the desired flow rate. The variable pressure fluid supplies can be pneumatically driven.
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Citations
16 Claims
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1. A low flow rate precision flow controller system comprising:
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(a) a plurality of continuously variable pressure fluid supplies delivering a plurality of fluids; (b) a single fluid outlet being in fluid communication with the plurality of fluid supplies, the plurality of fluids being mixed before exiting through the outlet; (c) a plurality of pressure sources corresponding to the plurality of fluids, each pressure source applying pressure to each fluid; (d) a plurality of capillary tube thermal mass flowmeters, each flowmeter detecting the flow rate of each fluid of the corresponding plurality of fluids; and (e) a controller for electronic flow control in communication with the respective flowmeter and the respective pressure source, wherein the controller compares the respective measured flow rate to a respective desired flow rate and adjusts the respective pressure source so that the respective fluid flows at the respective desired flow rate, wherein the fluids flow out of the fluid outlet at a flow rate of less than approximately 100 microliters/minute. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A low flow rate precision flow controller system comprising:
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(a) a plurality of fluid supplies in fluid communication with a fluid outlet so that a plurality of fluids mix before flowing through the outlet; (b) a mechanical pump for each fluid applying pressure to the respective fluid; (c) a capillary-tube thermal mass flowmeter for each fluid for measuring the flow rate of the respective fluids; (d) a thermocouple in communication with the capillary-tube thermal mass flowmeter for taking a temperature measurement; and (e) at least one controller for each mechanical pump in communication with the respective flowmeter via respective thermocouple and the respective pressure source, wherein the at least one controller compares the respective measured flow rate to a respective desired flow rate and adjusts the respective mechanical pump so that the respective fluid flows at the respective desired flow rate, wherein the fluids flow out of the fluid outlet at a flow rate of less than approximately 100 microliters/minute.
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Specification