Medical ventilator
Patent 5474062 Issued on December 12, 1995. Estimated Expiration Date: 
December 12, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 12, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorsAssigneeApplicationNo. 406914 filed on 09/13/1989US Classes:128/205.24, Valve, or valve control, structure128/204.18, Means for supplying respiratory gas under positive pressure128/204.21, Electric control means128/204.27Snap action toggle included in control mechanismExaminersPrimary: Howell, Kyle L.Assistant: Lacyk, John P. Attorney, Agent or FirmForeign Patent References
International ClassA62B 009/02AbstractA medical ventilator having a valve which controls the flow of gas from a pressurized gas source to a patient for inhalation. Flow through the valve is choked and pressure upstream of the valve is held stable so that a known relationship exists between the position of the valve and the flow rate through the valve. An open loop control system causes the valve to open or close as needed to deliver a preselected tidal volume of gas to the patient on each breath. Since the flow rate is known, no feedback to the controller regarding actual flow conditions is required. The exact positioning of the valve and length of time that the valve is to be held open is predetermined by the controller before the breath is delivered, and is repeated for subsequent breaths. Preferably, the valve is driven by a stepping motor, and the controller comprises a microcomputer. The controller compensates for ramping of the stepping motor as the valve opens and closes in determining the positions of the valve required to deliver the preselected tidal volume. To ensure precise engagement between a valve member and a valve seat, the valve member is mounted on a flexible, linear wire. Additionally, a spirally-wound spring surrounds a stepping motor shaft and biases the shaft so as to close the valve in the event of a power loss.Other References
Field of SearchValve, or valve control, structureMeans for sensing condition of user's body Electric control means Means for supplying respiratory gas under positive pressure RESPIRATORY METHOD OR DEVICE Means for sensing partial pressure, or amount, of component in gas mixture Gas stream passed through jet nozzle or venturi passage Means for varying air/oxygen ratio Gas supplied by piston pump Indicator structure Encased | |
