US 5,858,063 A · Oxygen concentrator with beds' duty cycle control and self-test

Abstract

A method of controlling an oxygen concentrator having a first sieve bed operated over successive control periods according to a duty cycle for alternately pressurizing and flushing the first sieve bed and a second sieve bed operated over the successive control periods according to a reciprocal of the duty cycle is disclosed. The duty cycle and the reciprocal duty cycle are adjusted during every second one of the successive control periods to change the pressurizing relative to the flushing of the first sieve bed and to change the flushing relative to the pressurizing of the second sieve bed, for reducing concentration of oxygen produced. The duty cycle and the reciprocal duty cycle are adjusted during remaining control periods to change the flushing relative to the pressurizing of the first sieve bed and to change the pressurizing relative to the flushing of the second sieve bed, such that water vapor is purged from the first and second sieve beds after pressurizing thereof. A pressure-swing adsorption (PSA) subsystem performance check is disclosed. This test is performed as part of a maintenance BIT (Built-In-Test) function. After verifying that the oxygen sensor accuracy is acceptable using prior art techniques, a set of bleed valves are opened to load the oxygen concentrator at a specific flow. The oxygen concentration is then checked via the sensor to determine whether the PSA subsystem is operating to within a predetermined concentration level.

Claims17

Dependent claims

A method of controlling performance of an oxygen concentrator having a first molecular sieve bed which is operated over successive control periods according to a duty cycle, said duty cycle including time periods for alternately pressurizing and flushing said first molecular sieve bed, and a second molecular sieve bed which is operated over the successive control periods, said duty cycle including time periods having a length which is a reciprocal of said time periods of the first molecular sieve bed during a particular control period for alternately flushing and pressuring said second molecular sieve bed, the method comprising the steps of:

a) adjusting said time periods during successive duty cycles and successive time periods during the reciprocal duty cycle during every second one of said successive control periods to change the time period for pressurizing relative to the time period for flushing of said first molecular sieve bed and to change the time period for the flushing relative to the time period for the pressurizing of the second molecular sieve bed, thereby degrading performance of the oxygen concentrator for reducing concentration of oxygen produced by the oxygen concentrator;
and
b) adjusting the time period during the duty cycle and the time period during the reciprocal duty cycle during remaining control periods to change the time period for the flushing relative to the time period for the pressurizing of the first molecular sieve bed and to change the time period for the pressurizing relative to the flushing of the second molecular sieve bed, such that water vapor is purged from the first and the second molecular sieve beds after pressurizing thereof.

An aircraft oxygen system for providing a controlled concentration of oxygen to the cabin of said aircraft, comprising:

a) an air inlet;
b) an exhaust port;
c) a slide valve connected to said air inlet and said exhaust port;
d) first and second molecular sieve beds each having an inlet connected to said slide valve and an outlet to said cabin;
and
e) a controller for operating said slide valve over successive control periods at high altitudes according to a duty cycle for alternately pressurizing and flushing said first molecular sieve bed and a reciprocal of said duty cycle for alternately flushing and pressurizing said second molecular sieve bed to generate oxygen enriched product gas, said duty cycle including time periods having a length for said first molecular sieve bed and a time period for the second molecular sieve bed which is a reciprocal of the length of the time period for said first molecular sieve bed, said controller controlling said slide valve by adjusting said duty cycle and said reciprocal duty cycle during every second one of said successive control periods to change the time period of the first molecular sieve bed for pressurizing relative to said flushing of said first molecular sieve bed and to change the time period of the second molecular sieve bed flushing relative to said pressurizing of said second molecular sieve bed, thereby changing the concentration of oxygen in said product gas, such that water vapor is purged from said first and second molecular sieve beds after pressurizing thereof.

3 more elements

Dependencies are inferred from the claim text.

Oxygen concentrator with beds' duty cycle control and self-test

Life of this patent

Oxygen concentrator with beds' duty cycle control and self-test

Life of this patent

Abstract

Claims17