摘要 |
An apparatus is described for calibrating at least one sensor within a gas detector ( 22 ), which detector has a gas inlet in fluid communication with the or each sensor, the apparatus comprising a housing ( 10 ) that contains: a) a surface ( 24 ) for abutting against the detector ( 22 ); b) a holder ( 14 ) for holding the gas detector ( 22 ) with respect to the housing ( 10 ) in such a manner that a region of the detector containing the gas inlet abuts against the surface ( 24 ) of the housing to form a sealed gas interface between the surface ( 24 ) and the detector ( 22 ); c) a connector for connecting a source of pressurised calibration gas ( 12 ) to the apparatus, d) a conduit ( 32 ) for delivering a calibration gas from the connector ( 34 ) to the interface between the detector and the apparatus housing, e) electrical connections ( 40 ) within the holder for forming electrical connections between the apparatus and a detector held within the holder, and e) a flow controller ( 34, 36 ) within the conduit for providing calibration gas at a predetermined level to the interface, the flow controller including an electrically-operated valve ( 36 ) being controllable for initiating and terminating the flow of calibration gas through the conduit ( 32 ) by means of signals received from the detector via the electrical connections ( 40 ). The whole calibration is controlled by the detector and not the calibration apparatus. |