Pneumatically coupled direct drive fluid control system and process
First Claim
1. A process for controlling an infusion of fluid from a fluid source to a liquid sink, comprising:
- a) exerting a negative pressure on a gas reservoir in fluid communication with a gas-side chamber separated from a fluid-side chamber by a flexible membrane to draw fluid from the fluid source into the fluid-side chamber through a one-way inlet valve until the fluid-side chamber fills with fluid;
b) exerting a positive pressure on the gas reservoir in fluid communication with the gas-side chamber by effecting a plurality of known, incremental changes in a volume of the gas reservoir as a series of discrete steps to deliver fluid in the fluid-side chamber to the liquid sink through a one-way outlet valve, wherein the one-way inlet valve and one way outlet valve each are passively operated and only open when a pressure differential between an upstream fluid and a downstream fluid reaches a predetermined cracking pressure;
c) monitoring pressure in the gas reservoir during the steps of exerting the negative pressure and exerting the positive pressure; and
d) determining volumes of fluid in the fluid-side chamber from the plurality of known, incremental changes in the volume of the gas reservoir and the gas-side chamber and any connecting dead space by an ideal gas law relationship, wherein P1V1=P2V2, wherein P1 and P2 are pressures measured before and after volume changes, respectively, and V1 and V2 are volumes before and after the volume changes, respectively.
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Accused Products
Abstract
A fluid control system for delivery of a liquid includes a pneumatic drive that incorporates a linear actuator to effect known volume changes in a gas reservoir. The gas reservoir is in fluid communication with a gas-side reservoir that is separated from a fluid-side reservoir by a flexible membrane. Movement of the linear actuator effects positive or negative volume differences on the gas in the gas-side reservoir, resulting in a decrease or increase in pressure of the gas that is transmitted to the fluid-side reservoir to draw fluid, primarily liquid, in from a source or deliver liquid out to a sink. In another aspect, a mechanism is provided for the detection and elimination of air bubbles in the fluid path.
64 Citations
11 Claims
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1. A process for controlling an infusion of fluid from a fluid source to a liquid sink, comprising:
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a) exerting a negative pressure on a gas reservoir in fluid communication with a gas-side chamber separated from a fluid-side chamber by a flexible membrane to draw fluid from the fluid source into the fluid-side chamber through a one-way inlet valve until the fluid-side chamber fills with fluid; b) exerting a positive pressure on the gas reservoir in fluid communication with the gas-side chamber by effecting a plurality of known, incremental changes in a volume of the gas reservoir as a series of discrete steps to deliver fluid in the fluid-side chamber to the liquid sink through a one-way outlet valve, wherein the one-way inlet valve and one way outlet valve each are passively operated and only open when a pressure differential between an upstream fluid and a downstream fluid reaches a predetermined cracking pressure; c) monitoring pressure in the gas reservoir during the steps of exerting the negative pressure and exerting the positive pressure; and d) determining volumes of fluid in the fluid-side chamber from the plurality of known, incremental changes in the volume of the gas reservoir and the gas-side chamber and any connecting dead space by an ideal gas law relationship, wherein P1V1=P2V2, wherein P1 and P2 are pressures measured before and after volume changes, respectively, and V1 and V2 are volumes before and after the volume changes, respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification