ACCURATE METERING SYSTEM
First Claim
1. An accurate metering device comprising:
- a fluid dispensing container containing a fluid to be dispensed, wherein said fluid dispensing container comprises a reducible volume;
a movable portion that is free to move in response to changes in fluid volume of said fluid contained within said fluid dispensing container;
a net fluid volume, wherein said net fluid volume within said fluid dispensing container changes as said movable portion moves with respect to said fluid dispensing container;
a metering drive that selectively contacts said movable portion;
a starting point comprising a point wherein said metering drive is re-zeroed; and
wherein said metering drive is actuated a known amount from said starting point thus moving said movable portion and reducing said reducible volume of said fluid dispensing container and causing a specific quantity of said fluid to be dispensed from said fluid dispensing container.
3 Assignments
0 Petitions
Accused Products
Abstract
The present invention is directed to metering devices, systems, and methods that mitigate differential thermal expansion/contraction for the efficient, accurate, and reproducible metered delivery of fluids. The present invention allows the net fluid volume and a plunger location within a fluid dispensing container to automatically adjust under the influence of differential thermal expansion/contraction between the fluid and the fluid dispensing container that the fluid is contained within. Further, the present invention allows the metering system drive to sense the adjusted plunger location and allows the metering system drive to re-zero itself to produce an accurate volumetric delivery of fluid from the fluid dispensing container. The metering system includes means for controlling the travel of the metering system drive, and hence the travel of the plunger into the fluid dispensing container, for delivering accurate/precise amounts of the fluid from the fluid dispensing container. The metering system may also mitigate dead volume in the metering system.
55 Citations
60 Claims
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1. An accurate metering device comprising:
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a fluid dispensing container containing a fluid to be dispensed, wherein said fluid dispensing container comprises a reducible volume; a movable portion that is free to move in response to changes in fluid volume of said fluid contained within said fluid dispensing container; a net fluid volume, wherein said net fluid volume within said fluid dispensing container changes as said movable portion moves with respect to said fluid dispensing container; a metering drive that selectively contacts said movable portion; a starting point comprising a point wherein said metering drive is re-zeroed; and wherein said metering drive is actuated a known amount from said starting point thus moving said movable portion and reducing said reducible volume of said fluid dispensing container and causing a specific quantity of said fluid to be dispensed from said fluid dispensing container. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A syringe-based metering system that mitigates differential thermal expansion, said syringe-based metering system comprising:
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a syringe defining an interior volume for containing a fluid; an outlet opening at a front end of said syringe; a piston-type plunger slidably disposed within said syringe through an opening in a rear end of said syringe; a net fluid volume defined by a location of said plunger within said syringe, wherein said net fluid volume changes with movement of said plunger within said syringe; and a metering drive that selectively engages and disengages said plunger, wherein said metering drive engages said plunger through said opening in said rear end of said syringe and is advanced to expel fluid from said syringe, wherein said metering drive disengages said plunger by being backed off of said plunger when said syringe-based metering system is not in use; wherein said plunger is permitted to slide axially within said syringe to mitigate differential thermal expansion and/or contraction between said syringe and said fluid contained within said syringe. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A method of mitigating the effects of differential thermal expansion in a metering system to ensure accurate metering of a fluid, said method comprising:
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containing a fluid to be dispensed in a fluid dispensing container having a reducible volume; providing a movable portion that can slide within said fluid dispensing container to reduce said reducible volume causing said fluid to be dispensed; providing a metering drive that can selectively engage said movable portion to move said movable portion causing said reducible volume of said fluid dispensing container to be reduced in an operating mode; and mitigating the effects of differential thermal expansion by allowing said metering drive to be backed off of said movable portion in a non-operating mode to provide a clearance between said movable portion and said metering drive. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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Specification