Demand-responsive gas blending system for medical ventilator
First Claim
1. A gas blending system for blending two gases in response to a sub-ambient demand applied by a ventilator or the like, said gas blending system comprising:
- positive displacement gas pump means for periodically creating said sub-ambient demand;
demand valve means, having an outlet, and an inlet adapted to be coupled to a pressure-regulated supply of a first gas, for providing a flow of said first gas from said inlet to said outlet, in proportion to the demand experienced by said outlet; and
a blending valve, having a first inlet coupled to the outlet of said demand valve means, a second inlet coupled to a substantially ambient-pressure supply of a second breathable gas, and a blended gas outlet adapted to be fluidly coupled to said gas pump means, wherein said blending valve includes proportioning means for selectively adjusting the relative flow capacities of said first and second inlets;
whereby, when said inlet of said demand valve means is coupled to a pressure-regulated supply of a first gas, and said blended gas outlet is coupled to said gas pump means, the total blended gas flow through said blended gas outlet is proportional to the total demand applied to said blended gas outlet by said gas pump means, and whereby the percentage of said first gas in said total blended gas flow is proportional to the ratio of the demand applied to said first blending valve inlet to the total demand applied to said blended gas outlet.
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Accused Products
Abstract
A gas blending system for use with a medical ventilator blends a pressurized gas with ambient air for delivery to the ventilator in response to the ventilator'"'"'s demand for gas during the gas intake phase of its cycle. The system comprises a demand valve that discharges a flow of the pressurized gas in proportion to the demand applied to its outlet. The demand valve outlet is coupled to a first inlet of a blending valve, a second inlet of which is open to the atmosphere. The blending valve has a blended gas outlet adapted to be coupled to the ventilator. The total demand applied by the ventilator to the blended gas outlet is transmitted to the first and second inlets. A proportioning mechanism in the blending valve adjusts the demand that is transmitted to the demand valve outlet through the blending valve first inlet as a percentage of the total demand applied to the blended gas outlet. The total flow of blended gas from the blended gas outlet is proportional to the total demand applied thereto, while the percentage of pressurized gas in the blended gas flow is proportional to the ratio of the demand applied to the first inlet to the total demand applied to the blended gas outlet. The pressurized gas percentage is determined only by the proportioning mechanism, and is independent of the total applied demand.
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Citations
27 Claims
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1. A gas blending system for blending two gases in response to a sub-ambient demand applied by a ventilator or the like, said gas blending system comprising:
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positive displacement gas pump means for periodically creating said sub-ambient demand; demand valve means, having an outlet, and an inlet adapted to be coupled to a pressure-regulated supply of a first gas, for providing a flow of said first gas from said inlet to said outlet, in proportion to the demand experienced by said outlet; and a blending valve, having a first inlet coupled to the outlet of said demand valve means, a second inlet coupled to a substantially ambient-pressure supply of a second breathable gas, and a blended gas outlet adapted to be fluidly coupled to said gas pump means, wherein said blending valve includes proportioning means for selectively adjusting the relative flow capacities of said first and second inlets; whereby, when said inlet of said demand valve means is coupled to a pressure-regulated supply of a first gas, and said blended gas outlet is coupled to said gas pump means, the total blended gas flow through said blended gas outlet is proportional to the total demand applied to said blended gas outlet by said gas pump means, and whereby the percentage of said first gas in said total blended gas flow is proportional to the ratio of the demand applied to said first blending valve inlet to the total demand applied to said blended gas outlet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A gas blending system for controllably blending a pressure-regulated gas with ambient air in response to a sub-ambient demand applied by a ventilator or the like, said system comprising:
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positive displacement gas pump means for periodically creating said sub-ambient demand; demand valve means having an inlet for receiving said pressure-regulated gas and an outlet for discharging a flow of said gas in response to a demand applied thereto; blending valve means, having a first inlet coupled to said outlet of said demand valve means, a second inlet for receiving ambient air, and a blended gas outlet adapted to be coupled to said gaspump means; and proportioning means, operatively associated with said blending valve means, for selectively controlling the relative proportions of said pressre-regulated gas and ambient air flowing into said blending valve means through said first and second inlets, respectivley, said proportioning means being position-adjustable between first and second limits of travel; whereby the total blended gas flow through said blended gas outlet is proportional to the total demand applied thereto by said gas pump means, and whereby the relative proportions of said pressure-regulated gas and ambient air in said blended gas flow are determined substantially solely by the position of said proportioning means. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A gas blending system for controllably blended a pressure-regulated gas with ambient air in response to a sub-ambient demand applied by a ventilator or the like, said system comprising:
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positive displacement gas pump means for periodically creating said sub-ambient demand; a demand valve having an inlet for receiving said pressure-regulated gas and an outlet for discharging a flow of said gas in proportion to the demand applied thereto; gas blending means having a first inlet coupled to said demand valve outlet, a second inlet open to the ambient atmosphere, and a blended gas outlet adapted to be fluidly coupled to said gas pump means, whereby a flow of the gases received from said first and second inlet is discharged through said blended gas outlet in response to the total demand applied thereto by said gas pump means; and proportioning means, in said gas blending means, for adjustably varying the percentage of the total demand applied to said blended gas outlet which is transmitted to said demand valve outlet through said first gas blending means inlet, said proportioning means being adjustable between a first position in which a minimum percentage of the total demand is applied to said demand valve outlet, and a second position in which a maximum percentage of the total demand is applied to said demand valve outlet; whereby the total blended gas flow from said blended gas outlet is proportional to the total demand applied thereto, and whereby the relative proportions of said pressure-regulated gas and ambient air in said blended gas flow are determined by the position of said proportioning means. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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Specification