Gas mixing apparatus for a ventilator
First Claim
1. A method for mixing gas for a ventilator system for supplying mixed gas to a patient airway during an inspiratory portion of a breath cycle, said ventilator system including a pump chamber, a gas displacement member disposed within said pump chamber, the gas displacement member being moveable between first and second positions, the method comprising the steps of:
- mixing a first selected gas with a second selected gas to provide mixed gas for the pump chamber;
moving the gas displacement member between said first position and said second position to deliver a flow of mixed gas from the pump chamber to the patient airway, and to draw mixed gas into the pump chamber.
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Accused Products
Abstract
The gas mixing apparatus provides the components of a breathing gas for mixing at approximately ambient atmospheric pressure, and regulates the pressure of a selected gas to approximately ambient atmospheric pressure for mixing with air at ambient atmospheric pressure. The gas mixing apparatus includes a piston disposed within a pump chamber. A flow limiting inlet controls introduction of a first selected gas such as oxygen for mixing with a second selected gas such as air. The pressure of the first selected gas is limited to an acceptable maximum pressure, so that even if a valve for admitting the first selected gas for mixing at ambient pressure fails, breathing gas will not be provided at an excessive pressure. A demand valve is alternatively provided for reducing the pressure of the first selected gas supplied before mixing, but a pressure sensor is also provided downstream of the demand valve for detecting failure of the demand valve, to shut off the supply of the first selected gas to prevent overpressurization.
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Citations
4 Claims
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1. A method for mixing gas for a ventilator system for supplying mixed gas to a patient airway during an inspiratory portion of a breath cycle, said ventilator system including a pump chamber, a gas displacement member disposed within said pump chamber, the gas displacement member being moveable between first and second positions, the method comprising the steps of:
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mixing a first selected gas with a second selected gas to provide mixed gas for the pump chamber;
moving the gas displacement member between said first position and said second position to deliver a flow of mixed gas from the pump chamber to the patient airway, and to draw mixed gas into the pump chamber. - View Dependent Claims (2, 3, 4)
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Specification