Systems and methods presented herein provide for multivariable model predictive control of a multistep plant. In one embodiment, a model predictive controller (MPC) includes a model of the multistep plant. The MPC is operable to linearize at least two steps of the multistep plant into cycle steps based on the model, to process an output signal from the multistep plant, and to independently control the cycle steps based on the output signal to optimize an output of the multistep plant.

Apparatus provide gas sensing operations such as for oxygen concentration sensing with an oxygen concentrator. In some versions, gas concentration sensing apparatus with pressure, temperature and/or mass flow sensors measure characteristics of a gas mixture in a vessel. A controller of the apparatus may estimate concentration of a constituent gas in the gas mixture as a function of the measured pressure, temperature and mass flow rate. In some versions, the sensing apparatus may measure a thermal conductivity of enriched gas, and, with a controller, estimate concentration of argon in the enriched gas from the thermal conductivity. The controller may estimate concentration of oxygen in the enriched gas from the concentration of argon. In some versions, an oxygen concentrator may have a mass flow sensor and a controller configured to trigger bolus delivery and/or measure oxygen concentration, and/or regulate bolus profile based on signals from the mass flow sensor.

Provided are an oxygen concentrator, a control method, and a control program capable of preventing a drop in pilot pressure supplied to a pilot type solenoid valve used in at least either of the supply flow path opening/closing unit or the exhaust flow path opening/closing unit. An oxygen concentrator capable of preventing a pressure drop in both cylinders in the pressure equalization step and, as a result, preventing a drop in pilot pressure supplied to a pilot type solenoid valve used in at least either of the supply flow path opening/closing unit or the exhaust flow path opening/closing unit, as well as a pressure drop in the adsorption cylinder, by starting pressurization in advance in the already depressurized adsorption cylinder before the pressure equalization step.

Provided are an oxygen concentrator, a control method, and a control program capable of preventing an internal pressure drop of the concentrated oxygen gas tank in order to extract concentrated oxygen gas at a predetermined flow rate. An oxygen concentrator capable of preventing a pressure drop in both cylinders in the pressure equalization step and, as a result, preventing a drop in the internal pressure of a concentrated oxygen gas tank, by starting pressurization in advance in the already depressurized adsorption cylinder before the pressure equalization step.

An oxygen concentrator comprises a product tank that is fluidly coupled to at least one sieve bed, and a product gas accumulator tank that is fluidly coupled to the product tank via a first conduit and to an outlet port via a second conduit, wherein the first conduit and the second conduit are disposed to allow at least a portion of product gas to flow from the product tank to the outlet port.

Disclosed herein is a device that functions as a glucose sensor. The device has a reference electrode; a counter electrode, a working electrode; an electrically conducting membrane; an enzyme layer; a semi-permeable membrane; a first layer of a first hydrogel in operative communication with the working electrode; the first layer of the first hydrogel being operative to store oxygen; wherein the amount of stored oxygen is proportional to the number of freeze-thaw cycles that the hydrogel is subjected to; and a second layer of the second hydrogel. Disclosed too is a method that comprises using periodically biased amperometry towards interrogation of implantable glucose sensors to improve both sensor's sensitivity and linearity while at the same time enable internal calibration against sensor drifts that originate from changes in either electrode activity or membrane permeability as a result of fouling, calcification and/or fibrosis.

Oxygen production process of VSA type from a flow of air, implementing at least one group of at least 3 adsorbers installed in parallel and following the same VSA cycle comprising, in succession, a phase of adsorption at the high pressure of the cycle, a phase of desorption at pressures lower than the high pressure of the cycle, a phase of repressurization of the adsorber to the high pressure of the cycle, characterized in that, periodically or exceptionally: a) at least one adsorber of the group of adsorbers is isolated so as to no longer follow the pressure cycle, b) the adsorbent contained in the adsorber isolated in the step a) is regenerated by raising the temperature, and c) the adsorber regenerated in the step b) is re-incorporated in the group of adsorbers so as to once again follow the pressure cycle.

This disclosure relates to a portable oxygen concentrator system. The system includes a case containing a portable oxygen concentrator, a mask, and a button. The case is configured to be worn on a user's back. The mask is configured to deliver oxygen from the portable oxygen concentrator to the user. The button, when activated, is configured to cause the portable oxygen concentrator to deliver an increased flow of oxygen to the user for a period of time.

An oxygen concentrator comprises a product tank that is fluidly coupled to at least one sieve bed, and a product gas accumulator tank that is fluidly coupled to the product tank via a first conduit and to an outlet port via a second conduit, wherein the first conduit and the second conduit are disposed to allow at least a portion of product gas to flow from the product tank to the outlet port.

Systems and methods for producing a product gas are provided. In one embodiment, a system includes at least one separation bed to separate adsorbable components from a gas source, a valving means to selectively direct gas from the gas source to the at least one separation bed, at least one sensing device associated with the at least one separation bed to sense the progress of an adsorption zone within the separation bed, and a controller. The controller includes logic to read the output of the at least one sensing device and control the gas separation process based on the progress of the adsorption zone.