PURPOSE: To provide a system for inspecting the sensitivity of a specific gas detection head without interrupting the operation of the entire gas leak monitoring system and which can be installed in an existing facility without requiring significant modification.
CONSTITUTION: A standard gas can be fed from a standard gas cylinder 11 through a stop valve 12 and a gas detection head 1 is fed selectively with the standard gas or a sample gas from a region to be monitored through a change- over valve 14. A processing circuit 15 delivers a pseudo-signal representative of normal state to an indicator 6 and a signal is delivered from the gas detection head 1 to a controller 17 having decision function. This constitution allows inspection only of a specific gas detection head without causing alarm operation in the indicator 6.
ARAI HIROO
IBA TOSHIRO
KOIKE HIDEKI
HITACHI LTD