Litton Systems, Inc.

David N Alftine

Tuan Q Cao

Richard W Hradek

William P Myers

In an oxygen concentrator which is intended for aircraft use, a booster compressor is used to increase the pressure of the product gas from the concentrator in order to increase the amount of the gas which can be stored in a plenum. The booster includes two moving pistons which are rigidly linked together and a series of check valves which control the flow of gases through the compressor. One of the pistons is driven by air from the rotary valve in the concentrator, and the other piston compresses the product gas for delivery to the plenum. A small sample of concentrator product gas is monitored by an oxygen sensor for oxygen concentration. Once the oxygen concentration has reached an acceptable level the booster compressor fills the plenum with product gas. Thereafter, if oxygen concentration of product gas delivered to the crew from the concentrator falls below the concentration which is required at a particular altitude, the product gas stored in the plenum is delivered to the crew. The oxygen sensor monitors the concentrator output product gas to the breathing regulator when the stored plenum gas is not being used.

Oxygen concentrator with pressure booster and oxygen concentration

A monitoring system for determining the concentration of oxygen in the product gas of an oxygen enriching system includes differential pressure regulator means for reducing the pressure of the product gas, for regulating the pressure of the product gas at a preset level, and for referencing the regulated pressure to atmospheric pressure. Solenoid valves allowing product gas to pressurize the monitoring system in a first condition and to allow product gas to vent the monitoring system to the atmosphere in a second condition are also included. Restrictive orifices upstream and downstream of a bed of molecular sieve material eliminate pressure spikes in the monitoring system. A bed of molecular sieve material to adsorb oxygen from the product gas wherein, in a first condition, with the system pressurized, the upper pressure limit is attenuated as the molecular sieve bed absorbs oxygen from the product gas, and, in a second condition, with the system vented to the atmosphere, the lower pressure limit is attenuated by the rate of desorption of the oxygen from the molecular sieve bed. Further included is a pressure transducer with means for converting the system pressure to an electrical analog of that pressure including means for comparing the electrical analog to a reference and inferring oxygen concentration.

Molecular sieve oxygen monitor

A monitoring system for determining the concentration of oxygen in the product gas of an oxygen enriching system comprises a plurality of pneumatic nor gates. Means are provided for coupling the outlet port of each gate to the control port of the subsequent gate to form a closed loop and a plurality of molecular sieve beds are pneumatically connected one each to the control port of the nor gates. The molecular sieve beds adsorb oxygen from the product gas to attenuate the rate of pressure change in the control ports and thus, the oscillation frequency of the monitor. The oxygen concentration of the product gas may be inferred from the oscillation frequency of the monitor.

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Bettendorf, IA, United States of America

David N Alftine