Ventilator system
First Claim
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1. A ventilator for patients needing assistance in breathing, comprising:
- a) a compressor having an air input and an air output, and being arranged to compress said air at said output to a first pressure level;
b) a flow valve having an inlet and an outlet, and a valving element interposed therebetween, said air at said first pressure level being applied to said inlet, and said air exiting said outlet at a second pressure level;
c) a bypass valve arranged to receive a portion of said air at said first pressure level and to discharge said air into the input side of said compressor when said bypass valve is open;
d) said bypass valve being biased with a bias toward the closed position and being further so connected to said outlet of said flow valve that said bypass valve opens whenever said first pressure level exceeds the sum of said bias plus said second pressure level; and
e) a conduit arranged to introduce said air exiting said outlet into the lungs of said patient.
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Abstract
A portable mechanical ventilator uses a constant-speed compressor compressor and a recirculating bypass circuit. Bypass flow is governed by a spring-biased bypass valve so connected to both the inlet and the outlet of the main flow control valve as to maintain a differential pressure across the flow valve sufficient to operate the ventilator with minimal energy consumption. The flow valve is operated by a microprocessor in accordance with empirically derived lookup tables to both produce the desired air flow and provide a measure of that air flow.
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Citations
16 Claims
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1. A ventilator for patients needing assistance in breathing, comprising:
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a) a compressor having an air input and an air output, and being arranged to compress said air at said output to a first pressure level; b) a flow valve having an inlet and an outlet, and a valving element interposed therebetween, said air at said first pressure level being applied to said inlet, and said air exiting said outlet at a second pressure level; c) a bypass valve arranged to receive a portion of said air at said first pressure level and to discharge said air into the input side of said compressor when said bypass valve is open; d) said bypass valve being biased with a bias toward the closed position and being further so connected to said outlet of said flow valve that said bypass valve opens whenever said first pressure level exceeds the sum of said bias plus said second pressure level; and e) a conduit arranged to introduce said air exiting said outlet into the lungs of said patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for closed-loop control of air flow through a ventilator valve without measuring said air flow, comprising the steps of:
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a) providing a valve with known flow path cross sections at various valve positions; b) producing a pressure differential between the inlet and the outlet of said valve; c) monitoring said pressure differential; d) controlling the position of said valve in accordance with a control signal; and e) using said pressure differential and said control signal to adjust said control signal for producing a desired air flow. - View Dependent Claims (14)
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15. In a ventilator for patients needing assistance in breathing, a self-regulating flow control system, comprising:
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a) a flow valve having an inlet and an outlet and defining a gas flow path between the inlet and the outlet, the flow valve including a valving element in the gas flow path that is movable through a plurality of positions, each of which defines a specific cross-sectional area of the gas flow path, whereby a differential pressure is developed between the inlet and the outlet, and a gas flow rate is generated through the outlet that is a function of the cross-sectional area of the gas flow path; b) a pressure transducer in communication with the inlet and the outlet so as to generate a differential pressure signal indicative of the differential pressure; and c) a controller arranged to control the position of the valving element, the controller receiving the differential pressure signal and a position value indicative of the position of the valving element, wherein the controller, in response to the position value and the differential pressure signal, adjusts the position of the valving element for closed loop control of the gas flow rate. - View Dependent Claims (16)
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Specification