Abstract: A dual gas sensor is described, having first and second working electrodes separated by a gas impermeable portion. The electrodes are preferably located on a gas permeable polymer support, with the gas impermeable portion being formed by compression of the permeable support. The sensor may also include one or more filters for location adjacent the electrodes to filter certain gases from the air. The preferred sensor is able to detect carbon monoxide and hydrogen sulfide. The sensor housing is formed with four connection pins, allowing a standard sensor housing to be used for dual sensors as well as single sensors having a dummy pin.

Abstract: An electrochemical gas sensor comprises: a working electrode for exposure to a gas to be sensed; a counter electrode having an outer periphery; a reservoir for electrolyte; wick means providing a path for electrolyte to pass from the reservoir, around a first part or parts of the outer periphery of the counter electrode to provide electrolytic continuity between the counter electrode and the working electrode; and a gas diffusion means providing a path for gas to diffuse to or from a second part or parts of the outer periphery of the counter electrode.

Abstract: Electrochemical sensor for determining analyte in the presence of interferent, particularly carbon monoxide in the presence of hydrogen. An electrochemical cell is designed so that current flow resulting from reference electrode potential shift caused by interferent cancels out the current flow caused by interferent at the working electrode. Another electrochemical cell corrects for interferent concentration using the potential difference between a reference electrode in contact with interferent and a referent electrode not affected by inteferent.

Abstract: An electrochemical gas sensor comprises: a working electrode for exposure to a gas to be sensed; a counter electrode having an outer periphery; a reservoir for electrolyte; wick means providing a path for electrolyte to pass from the reservoir, around a first part or parts of the outer periphery of the counter electrode to provide electrolytic continuity between the counter electrode and the working electrode; and a gas diffusion means providing a path for gas to diffuse to or from a second part or parts of the outer periphery of the counter electrode.

Abstract: Electrochemical sensor for determining analyte in the presence of interferent, particularly carbon monoxide in the presence of hydrogen. An electrochemical cell is designed so that current flow resulting from reference electrode potential shift caused by interferent cancels out the current flow caused by interferent at the working electrode. Another electrochemical cell corrects for interferent concentration using the potential difference between a reference electrode in contact with interferent and a referent electrode not affected by inteferent.

Abstract: A sonde is provided which includes a plurality of discrete sensing electrodes of analog output projecting from a housing within which are accommodated a micro-processor and an analog-digital converter to digitize the output of the electrodes. A stirrer is fully integrated into the housing and projects from the housing centrally with the electrodes around it. The stirrer motor and the stirrer control are integrated into the housing. The micro-processor controls the stirrer control. The sonde also has a readily attachable and detachable calibration cup with wells defined therein. Each well is designed to receive its own liquid. The calibration cup is designed such that all the electrodes can be calibrated simultaneously.

Abstract: A multi-probe metering apparatus is characterized by a central unit (I) comprising various signal processing circuits and modules (II) having two gates (A, B) to which are connected various pick-ups (III). The central unit (I) communicates with the module (II) via a numerical signal link (10) for the transmission of pick-up identification signals, and by two analogue links (9, 9b) permitting simultaneous connection of two pick-ups.