Molecular sieve oxygen monitor

Abstract

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.