Abstract: A gas sensor having a housing with first and second chambers featuring a porous separator located there between. The first chamber of the sensor being connected to atmosphere via a gas diffusion aperture. The gas sensor having a sensing electrode disposed within the first chamber and at least a second electrode disposed within the second chamber. The sensor having an ionic liquid electrolyte disposed within the second chamber where the sensing electrode and at least second electrodes comprise platinum.

Abstract: An electrochemical gas sensor having an electrode with a catalyst distributed on a porous surface is described. The porous surface can be a polytetrafluoroethylene tape. Alternate embodiments include layered or stacked electrodes.

Abstract: An electrochemical oxygen sensor includes a micro-porous plastic membrane supported on a sealing disk and located between a gas inflow port and the sensor's electrolyte. The membrane and disk minimize thermal shock effects due to using the sensor at a first location, at a first temperature, and then moving it to a second location at a different temperature.

Abstract: Devices and methods are disclosed that can adjust a hydration level in an electrochemical sensor or an instrument which includes such a sensor. The device can include a chamber which can, at least in part, surround an inflow port of the sensor. An adjacent reservoir of water can provide a source of water vapor which can be infused into the sensor.

Abstract: An electrochemical detector includes a carbon based element located between a separator and a current collector of an adjacent electrode. Elements can take the form of a carbon fabric located between the separator and the collector, or a linear, or, circular carbon deposit on a surface of the separator adjacent to the respective current collector. Other conductive coatings including gold, platinum or transition metals, as well as carbon, can be deposited directly onto a porous substrate, such as a masked separator material.

Abstract: A method of operating an electrochemical gas sensor includes: a) exposing, for a first predetermined duration, the electrochemical gas sensor to an atmosphere containing a target gas while the gas reaction capability of the electrode assembly is substantially reduced from a working level, such that target gas is collected within the housing; b) increasing the gas reaction capability of the electrode assembly to a level at which it consumes collected target gas and thereby outputs a signal to the sensing circuit, including an initial transient decay signal; c) monitoring the transient decay signal; and d) analysing the rate of decay of the transient decay signal to determine whether the performance of at least one component of the electrochemical gas sensor is within acceptable limits. An apparatus for operating an electrochemical gas sensor, adapted for connection to an electrochemical gas sensor via a sensing circuit for control thereof, can carry out the disclosed method(s).

Abstract: An electrochemical oxygen sensor includes a micro-porous plastic membrane supported on a sealing disk and located between a gas inflow port and the sensor's electrolyte. The membrane and disk minimize thermal shock effects due to using the sensor at a first location, at a first temperature, and then moving it to a second location at a different temperature.

Abstract: A gas detector includes at least two electrodes. The electrodes are carried on a common substrate having first and second spaced apart surfaces. The electrodes are formed on respective ones of the surfaces with the substrate sandwiched therebetween.

Abstract: An electrochemical oxygen sensor includes a micro-porous plastic membrane supported on a sealing disk and located between a gas inflow port and the sensor's electrolyte. The membrane and disk minimize thermal shock effects due to using the sensor at a first location, at a first temperature, and then moving it to a second location at a different temperature.

Abstract: An electrochemical sensor includes a micro-porous plastic membrane supported on a disk and located between a gas inflow port and an electrolyte having a gelled oxygen diffusion barrier. The oxygen diffusion barrier, formed of gelled agar, minimizes thermal shock effects by impregnating any porous materials in the sensor.

Abstract: A method of improving performance of electrochemical gas sensors includes cycling potentials applied to one or more of the electrodes of the respective sensor(s) to improve performance of a different electrode. In a process for treating a reference electrode, potentials can be applied to working and, or counter electrodes so as to modify the environment in the vicinity of the reference electrode. An apparatus can carry out the method automatically.

Abstract: A method of operating an electrochemical gas sensor includes: a) exposing, for a first predetermined duration, the electrochemical gas sensor to an atmosphere containing a target gas whilst the gas reaction capability of the electrode assembly is substantially reduced from a working level, such that target gas is collected within the housing; b) increasing the gas reaction capability of the electrode assembly to a level at which it consumes collected target gas and thereby outputs a signal to the sensing circuit, including an initial transient decay signal; c) monitoring the transient decay signal; and d) analysing the rate of decay of the transient decay signal to determine whether the performance of at least one component of the electrochemical gas sensor is within acceptable limits. An apparatus for operating an electrochemical gas sensor, adapted for connection to an electrochemical gas sensor via a sensing circuit for control thereof, can carry out the disclosed method(s).

Abstract: A liquid electrolyte composition obtainable by combining a first component comprising bistrifluoromethanesulfonimide and/or an analogue thereof with a second component comprising a dialkyl sulfone, diaryl sulfone, alkyl aryl sulfone, alkyl acyl sulfone, boric acid, alkyl boronic acid, aryl boronic acid, dialkyl phosphite, trialkyl phosphite, dialkyl phosphate, trialkyl phosphate, alkylene carbonate, alkanoic lactone, preferably alkanoic ?-lactone an analogue of any of these, or mixtures thereof, wherein any of the alkyl, aryl of alkenyl groups may be substituted or unsubstituted. The liquid electrolyte is used in an electrochemical gas sensor.

Abstract: A monitor is disclosed for monitoring an atmosphere for the presence of a target gas. The monitor includes an electrical gas sensor having a working (sensing) electrode and a counter electrode, an operational amplifier connected between the sensor electrodes, a detector, and a circuit. The sensor provides a current between the electrodes that is indicative of the amount of a target gas in the atmosphere. The operational amplifier generates an output signal according to the current flowing between the terminals where the output signal is indicative of the amount of target gas in the atmosphere. The detector detects when the current flowing between the sensor electrodes exceeds a predetermined threshold. The circuit restricts the potential difference between the sensor electrodes when the current between the terminals exceeds the predetermined threshold by supplying additional current or removing current from the working sensor electrode.

Abstract: A process is described for manufacturing gas diffusion electrodes, which process comprises: (a) treating an area of a pre-shrunk porous hydrophobic substrate so as to restrict the slurry deposited in step b) to the said area, preferably by forming a well in the area and/or treating the substrate in the area to render it less hydrophobic, e.g. by plasma treating the area; (b) dispensing a slurry of catalyst onto the said area, (c) removing liquid from the dispensed slurry, (d) treating the dried slurry to remove organic materials and e) cutting the catalyst and the underlying portion of substrate from the rest of the substrate.

Abstract: Devices and methods are disclosed that can adjust a hydration level in an electrochemical sensor or an instrument which includes such a sensor. The device can include a chamber which can, at least in part, surround an inflow port of the sensor. An adjacent reservoir of water can provide a source of water vapor which can be infused into the sensor.

Abstract: A method and apparatus for gas detection uses a sensor such as an electrochemical (EC) cell and includes a feedback control loop to control a pump to establish a first predetermined gas flow rate to the EC cell. The concentration of the gas at the first predetermined flow rate is measured. If the detected concentration exceeds a predetermined Alert value at the first flow rate an Initial Warning without remedial action is generated, and, the system then changes the gas flow rate before an Alarm is indicated. An Alarm is signaled only if the system verifies the first measurement. Preferably the first flow rate is set to optimize the measurement accuracy of the EC cell being used, and the second flow rate is lower than the first. Verification of an Alarm at the first flow rate may be conducted quickly by a quick-reaction process. The controller may periodically cycle the flow rates between the first and second rates for better accuracy and faster verification times.

Abstract: An electrochemical oxygen sensor includes a micro-porous plastic membrane supported on a sealing disk and located between a gas inflow port and the sensor's electrolyte. The membrane and disk minimize thermal shock effects due to using the sensor at a first location, at a first temperature, and then moving it to a second location at a different temperature.

Abstract: A method and apparatus for gas detection uses a sensor such as an electrochemical (EC) cell and includes a feedback control loop to control a pump to establish a first predetermined gas flow rate to the EC cell. The concentration of the gas at the first predetermined flow rate is measured. If the detected concentration exceeds a predetermined Alert value at the first flow rate an Initial Warning without remedial action is generated, and, the system then changes the gas flow rate before an Alarm is indicated. An Alarm is signaled only if the system verifies the first measurement. Preferably the first flow rate is set to optimize the measurement accuracy of the EC cell being used, and the second flow rate is lower than the first. Verification of an Alarm at the first flow rate may be conducted quickly by a quick-reaction process. The controller may periodically cycle the flow rates between the first and second rates for better accuracy and faster verification times.

Abstract: A gas sensor assembly comprises a housing (65) including a bore (61). A pin (50) extends through the bore (61) and an O-ring (100) is located in the bore. The O-ring (100) contacts the pin (50) and parts of the bore (61) so as to be restrained against movement in both lateral and axial directions. Two- and three-shot molding processes are described for fabricating the assembly.