A portable oxygen concentrator includes at least one separation mechanism and an oxygen storage tank, where the separation mechanism is connected to the oxygen storage tank and includes an air bag and a molecular sieve tank that is filled with a molecular sieve for adsorption. The air bag has an air inlet and an air outlet. The air bag is connected to the molecular sieve tank through a valve group, which includes a first single valve and a second single valve. The air bag is connected to the molecular sieve tank through the first single valve. Each of the two ends of the molecular sieve tank has at least one gas outlet. When an inner space of the air bag is compressed and expanded once, the molecular sieve in the molecular sieve tank adsorbs and desorbs once.

A portable oxygen concentrator retrofit system and method in which an existing portable oxygen concentrator may be retrofitted to output an enriched oxygen gas at a flow rate suitable for use in a patient ventilation system without the need for an external source of compressed gas.

A method for separating N.sub.2 from a hydrocarbon gas mixture containing N.sub.2 comprising the steps of: i) providing a bed of adsorbent selective for N.sub.2; (ii) passing the hydrocarbon gas mixture through the bed of adsorbent to at least partially remove N.sub.2 from the gas mixture to produce: (a) N.sub.2-loaded adsorbent and (b) N.sub.2-depleted hydrocarbon gas mixture; iii) recovering the N.sub.2-depleted hydrocarbon gas mixture; iv) regenerating the N.sub.2-loaded adsorbent by at least partially removing N.sub.2 from the adsorbent; and v) sequentially repeating steps (ii) and (iii) using regenerated adsorbent from step (iv); wherein the adsorbent comprises a pyrolized sulfonated macroporous ion exchange resin.

Concentration of oxygen gas with electrochemical stacks arranged in series gas flow. A system includes a plurality of electrochemical stacks for extracting oxygen from an input gas, wherein the plurality of electrochemical stacks outputs oxygen gas and oxygen-reduced gas. The system includes a heat exchanger in fluid communication with the plurality of electrochemical stacks, wherein the heat exchanger consumes the input gas and the oxygen-reduced gas, and wherein the heat exchanger transfers heat from the oxygen-reduced gas to the input gas. The system includes a mechanical blower for driving the input gas into the heat exchanger. The system is such that the plurality of electrochemical stacks are organized in series gas flow.

Methods and apparatus may implement controlled generation of oxygen enriched air in an oxygen concentrator while implementing control that reduces pneumatic imbalance between the concentrator's canisters, such as dynamic pressure imbalance or other pneumatic characteristic. One or more controllers may regulate operation of a compressor that feeds a pressurised air stream to the concentrator's canisters. This may regulate speed of the compressor to a speed set point for generating the pressurised stream. The regulating may involve generating a compressor control signal having a characteristic parameter such as a power parameter. The controller(s) may operate valve(s) in a cyclic pattern so as to produce oxygen enriched air in an accumulator. A cycle of the cyclic pattern may include a plurality of phases, where each of the plurality of phases has a duration. The controller(s) may then generate a dynamic adjustment to the duration(s) based on an evaluation of the characteristic parameter.

A process for separating components of a fluid mixture using membranes comprising a selective layer made from copolymers of perfluorinated dioxolanes. The resulting membranes have superior selectivity performance for fluid pairs of interest while maintaining fast fluid permeance compared to membranes prepared using conventional perfluoropolymers, such as Teflon® AF, Hyfion® AD, and Cytop®.

An apparatus for separating oxygen from a gas mixture includes an oxide layer having ion transport channels therein, which facilitate the migration of oxygen ions from a first side to a second side of the layer. Molecular oxygen is decomposed into oxygen ions at the first side, whereas oxygen ions recombine into molecular oxygen at the second side. A first chamber into which a gas mixture (e.g., air) is admitted is located on the first side of the oxide layer. A second chamber receives oxygen from the oxide layer, and is located on the second side of the oxide layer; the second chamber has a polarizable medium that is in contact with the oxide layer. A gate electrode in contact with the polarizable medium applies an electric field to the second side of the oxide layer, thereby driving oxygen ions across the oxide layer.

Described herein are various embodiments of an oxygen concentrator system and method of delivering oxygen enriched gas to a user. In some embodiments, oxygen concentrator system includes one or more components that improve the efficiency of oxygen enriched gas delivery during operation of the oxygen concentrator system.

A battery retaining system for a portable oxygen concentrator includes a first rail configured to receive a first slide of a battery, a second rail configured to receive a second slide of the battery, the second rail being spaced apart from the first rail so as to form a channel configured to receive the battery, and a flexible stiffening mechanism configured to impart a biasing force on a surface of the battery when the battery is received within the channel. The flexible stiffening mechanism includes a protrusion projecting from the first rail at least partially towards the second rail and a slit positioned behind the protrusion and configured to facilitate travel of the protrusion fore and aft.

Provided are a methane-selective composite membrane comprising: a UiO-66 type organic-inorganic composite nanoporous material, a MIL-100 type organic-inorganic composite nanoporous material, or a ZIF-8 type organic-inorganic composite nanoporous material to which a methane-selective functional group is introduced for selectively separating methane from a gas mixture containing methane/nitrogen, a use thereof, and a method of preparing the same.