Recirculating breathing apparatus and method
First Claim
1. Apparatus for supplying a variable, controlled composition of a breathable gas mixture through oxygen in liquid-vapor form to a ventable breathing means at a variable ambient pressure, said apparatus comprising:
- a container (for the oxygen in liquid-vapor form) having an inlet and an outlet and adapted to hold oxygen in liquid-vapor form, said inlet located below the normal surface level of the liquid oxygen and said outlet located above the normal surface level of the liquid oxygen;
an inhale conduit at one end connected to the container outlet and at the other end adapted to be connected to the breathing means;
an exhale conduit at one end connected to the container inlet and at the other end adapted to be connected to the breathing means thereby forming a loop wherein gas exhaled by a user at the breathing means passes through the exhale conduit to the container where poisonous components of the gas are frozen out and the remaining gas bubbles through the oxygen in liquid-vapor form to replace consumed oxygen and the resultant gas is supplied to the user through the inhale conduit; and
means for heating the gas in the inhale conduit to substantially the temperature at which the gas is breathed.
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Accused Products
Abstract
A process for supplying the proper amount of oxygen in a breathing gas mixture of at least one inert gas for use at any pressure by passing the gas mixture through the liquid phase of a cryogenic liquid-vapor system containing oxygen and thereby saturating with oxygen the gas mixture at the system pressure. The saturation concentration of oxygen in the gas stream is controlled to the desired oxygen partial pressure substantially independent of the total pressure of gas mixture by controlling the temperature of the two-phase cryogenic system.
A device embodying the process includes oxygen in liquid-vapor form within a container to which are connected gas conduits, one for delivering the saturated breathing gas mixture to a user and the other for returning the exhaled gas to the container. A filter in the return conduit extracts carbon dioxide and water vapor. The return gas is cooled to the cryogenic temperature and the saturated gas is heated to breathing temperature by a heat exchanger thermally connecting the two conduits. The two-phase system is maintained at the proper constant temperature by submerging the container in a tank of liquid nitrogen and allowing the nitrogen to boil-off at a certain pressure. A supply of inert gas is stored under high pressure in the container. A regulator determines total pressure requirements for the user and releases sufficient inert gas through the liquid oxygen to maintain required total pressure.
57 Citations
15 Claims
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1. Apparatus for supplying a variable, controlled composition of a breathable gas mixture through oxygen in liquid-vapor form to a ventable breathing means at a variable ambient pressure, said apparatus comprising:
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a container (for the oxygen in liquid-vapor form) having an inlet and an outlet and adapted to hold oxygen in liquid-vapor form, said inlet located below the normal surface level of the liquid oxygen and said outlet located above the normal surface level of the liquid oxygen; an inhale conduit at one end connected to the container outlet and at the other end adapted to be connected to the breathing means; an exhale conduit at one end connected to the container inlet and at the other end adapted to be connected to the breathing means thereby forming a loop wherein gas exhaled by a user at the breathing means passes through the exhale conduit to the container where poisonous components of the gas are frozen out and the remaining gas bubbles through the oxygen in liquid-vapor form to replace consumed oxygen and the resultant gas is supplied to the user through the inhale conduit; and means for heating the gas in the inhale conduit to substantially the temperature at which the gas is breathed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification