Abstract: A combined toxic gas sensor and an oxygen sensor includes a sensor body 1 with a top plate 2 provided with a toxic gas diffusion barrier 3 leading to a chamber 7 from having an outlet aperture 5 registering with the diffusion barrier 6 of the oxygen sensor.

Abstract: A system for monitoring potentially hazardous atmospheres in work areas includes as part of a central console unit, a central, single or multi-gas fixed or mobile gas monitor fitted with a master radio transmitter unit adapted for communication with a plurality of mobile slave radio-pager units.

Abstract: A combined toxic gas sensor and an oxygen sensor includes a sensor body 1 with a top plate 2 provided with a toxic gas diffusion barrier 3 leading to a chamber 7 from having an outlet aperture 5 registering with the diffusion barrier 6 of the oxygen sensor.

Abstract: An electrochemical gas sensor having a housing in which components of the sensor are mounted. A number of electrical connectors are secured to the housing and coupled to respective sensor components enabling the sensor to be connected to a sensor monitoring system for monitoring an electrical output from the sensor and for determining gas concentration. The housing includes one or more indicating formations whose position on the housing causes an appropriate calibration parameter to be selected.

Abstract: An electrochemical gas sensor comprises sensing and counter electrodes mounted on the same side of a planar support. An electrolyte is in contact with the sensing and counter electrodes. A capillary controls the access of gas to the sensing electrode. A barrier layer extends over the sensing and counter electrodes, the barrier layer being positioned relative to the capillary and the support being non-electrically conductive and being sufficiently porous such that gas from the capillary is guided transversely and laterally through the support first to reach the sensing electrode and then to reach the counter electrode.

Abstract: An electrochemical gas sensor assembly comprises an electrochemical gas sensor (1) including sensing (39) and counter (32) electrodes, an intervening body of electrolyte contacting the electrodes, and means (5) for controlling the diffusion of gas to the sensing electrode. A test gas generator (7) is connected to the sensor so as to supply a test gas directly to the sensing electrode (39) by-passing the gas diffusion control means (5).