Backup breathing gas supply for an oxygen concentrator system

Claim 1

A backup breathing gas supply for use with an oxygen concentrator in which a source gas is coupled by a rotary valve to a plurality of beds of molecular sieve material in the concentrator to produce an enriched product gas at the concentrator outlet for delivery as a breathing gas to a breathing regulator, wherein the rotary valve periodically alternates the flow of the source gas to the plurality of beds of molecular sieve material in order to produce breathing gas, the backup breathing gas supply comprising: a plenum chamber for storing a quantity of breathing gas, a quantity of molecular sieve material contained in the plenum chamber, whereby the capacity of plenum chamber to contain breathing gas is increased by the addition of molecular sieve material, a plenum line coupling the outlet of the oxygen concentrator to the plenum chamber, a bypass line coupled to the outlet of the oxygen concentrator in parallel with the plenum line, control means for selectively coupling either the plenum chamber or the bypass line to the breathing regulator, said control means comprising a three-way valve coupled to the outlet of the plenum chamber and the bypass line, a check valve in the plenum line upstream of the plenum chamber whereby breathing gas fills said plenum chamber whenever the concentrator outlet pressure exceeds the plenum pressure, and whereby loss of stored gas from the plenum input through the bypass line to the breathing regulator when the concentrator outlet pressure is less than the plenum pressure is prevented, a rotation sensor means for detecting the failure of the rotary valve, said sensor means causing said control means to deliver breathing gas from the plenum chamber to the breathing regulator upon said failure, and restrictor means in the plenum line upstream of the plenum chamber for limiting the fill rate of the plenum chamber during periods when the concentrator output pressure exceeds the plenum pressure.