Composition pulse time-of-flight mass flow sensor
First Claim
1. A device for measuring the flow rate of a liquid in a flow channel, comprising:
- a pair of spaced-apart electrodes disposed along the liquid flow axis in the flow channel;
means for applying a voltage pulse to said pair of electrodes to produce a variation in the composition of the liquid;
means for detecting the compositional variation; and
means for measuring flight time.
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Accused Products
Abstract
A device for measuring fluid flow rates over a wide range of flow rates (<1 nL/min to >10 μL/min) and at pressures at least as great as 10,000 psi. The invention is particularly adapted for use in microfluidic systems. The device operates by producing compositional variations in the fluid, or pulses, that are subsequently detected downstream from the point of creation to derive a flow rate. Each pulse, comprising a small fluid volume, whose composition is different from the mean composition of the fluid, can be created by electrochemical means, such as by electrolysis of a solvent, electrolysis of a dissolved species, or electrodialysis of a dissolved ionic species. Measurements of the conductivity of the fluid can be used to detect the arrival time of the pulses, from which the fluid flow rate can be determined
47 Citations
17 Claims
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1. A device for measuring the flow rate of a liquid in a flow channel, comprising:
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a pair of spaced-apart electrodes disposed along the liquid flow axis in the flow channel;
means for applying a voltage pulse to said pair of electrodes to produce a variation in the composition of the liquid;
means for detecting the compositional variation; and
means for measuring flight time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A device for measuring liquid flow rates, comprising:
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a substrate fabricated to define a microchannel system disposed thereon, the microchannel system, in part, comprising;
a flow channel;
a pair of spaced-apart electrodes disposed along the liquid flow axis in the flow channel;
means for applying a voltage pulse to said pair of electrodes to produce a variation in the composition of the liquid;
means for detecting the compositional variation; and
means for measuring flight time. - View Dependent Claims (10, 11, 12)
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13. A device for measuring liquid flow rates at pressures as great as 10,000 psi, comprising:
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a flow channel;
a pair of spaced-apart electrodes disposed along the liquid flow axis in the flow channel;
means for applying a voltage pulse to said pair of electrodes to produce a variation in the composition of the liquid;
means for detecting the compositional variation; and
means for measuring flight time.
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14. A method for measuring liquid flow rates, comprising:
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providing a liquid flow channel;
flowing liquid through the flow channel;
producing a compositional variation in the liquid;
detecting the compositional variation; and
measuring the flight time of the variation.
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15. An electrode for electrokinetic systems, comprising;
an outer body fabricated from a microporous material and an inner metal electrode. - View Dependent Claims (16, 17)
Specification