Surgery – Respiratory method or device – Means for supplying respiratory gas under positive pressure
Reexamination Certificate
1999-04-26
2001-02-20
Lewis, Aaron J. (Department: 3761)
Surgery
Respiratory method or device
Means for supplying respiratory gas under positive pressure
C128S203110
Reexamination Certificate
active
06189532
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a valve for use in an oxygen or gas delivery system. In particular, the valve provides a safety mechanism wherein if a system which delivers oxygen or gas to a patient through a mask becomes dysfunctional, the valve opens to the atmospheric environment.
BACKGROUND OF THE INVENTION
Nasal masks currently are employed for various purposes, including the delivery of oxygen to persons who suffer from lung disease or who are exposed to rarefied atmospheres, for administering anesthetic gases and for delivering pressurized air to persons who suffer from disorders such as sleep apnea. The masks usually are molded from a relatively soft, resilient, elastic material and they are shaped during manufacture to match the facial contours of an average intended wearer. However, a problem with the known types of masks is that, because individuals vary so much from the average, the masks must be forced against their inherent resiliency to deform and so adapt to the shapes of the users in order to avoid gas leakage. This requires that the masks be secured firmly by retaining straps or harnesses in order to prevent air leakage.
Flow generators are typically utilized to deliver a breathable gas to a patient wearing a mask. The flow generator is generally connected to flexible tubing which is secured to a mask worn by a patient. If the flow generator's operation is interrupted as a result of a power outage or other mechanical or electrical failure, there may be a significant build up of carbon dioxide in the mask as the patients exhaled air is not washed out of outlet vents which are usually contained in the mask. This may present a health problem to the patient. Additionally, when oxygen is being delivered in a closed system by a flow generator, and there is a failure of the flow generator, oxygen may still be delivered. If and when power is restored to the flow generator, there may be a significant amount of oxygen present in the flow generator creating a possible explosion hazard. Finally, there are often humidifiers used with flow generators. Any water from the humidifier should be prevented from entering the generator.
There have been numerous patents which have addressed some sort of safety valve for gas or air delivery masks. An example of such a patent is U.S. Pat. No. 5,438,981. This patent utilizes a counter balanced, rigid valve element which depending on the gas flow, either covers an opening to the ambient air or covers the gas flow airway such that the air or breathing gas is forced out into the ambient air opening. However, this system suffers from being a fairly complicated and expensive system which must rely on a counter balanced moving part. Additionally, if any condensation from the air gets on or around the balanced valve element, the operation of this valve element may be compromised. Finally, this valve is difficult to clean.
Thus, there is a need for a valve with fewer moving parts and easier operation in the event of moisture or condensation entering the valve element.
SUMMARY OF THE INVENTION
The present invention is a slider valve element with a hollow or vented housing aligned with inlet orifices and exhaust vents. A returning force, such as a magnet or coil spring, is used to return the vented slide element to its resting position when the inlet orifices are blocked. When the air flow is applied to the inlet, the returning force is overcome wherein the slider element is pushed up to block the exhaust vents. Thereafter, the air flows through the slider and into the mask or tubing to provide therapy to the patient. If the airflow from the flow generator or air source is taken away, the returning force returns the slider element to block the inlet airway passage and thus opens the exhaust vent to the atmosphere. The valve is designed to fit directly onto a mask frame elbow and/or tubing and/or the outlet of the flow generator. There may also be multiple valves in a single system.
REFERENCES:
patent: 4449525 (1984-05-01), White et al.
patent: 4579114 (1986-04-01), Gray et al.
patent: 5230330 (1993-07-01), Price
patent: 5878743 (1999-03-01), Zdrojkowski et al.
patent: 5881722 (1999-03-01), Devries et al.
patent: 5896857 (1999-04-01), Hely et al.
patent: 5950623 (1999-09-01), Michell
patent: 6032667 (2000-03-01), Heinonen
patent: 6055981 (2000-05-01), Laswick et al.
Hely Kenneth Frederick
Lithgow Perry David
Lewis Aaron J.
Pillsbury Madison & Sutro LLP
ResMed Limited
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