| 摘要 |
For calibration of gas alarms, one uses a portable device 18, which produces the desired gas mixture of required type and concentration on site. The device contains an air pump 10 and a container 23 which can be connected to its outlet. A connection line 24 is provided to an evaporation chamber 25, preferably of self-sealing elastic material, in which an evaporable liquid can be injected in a quantity yielding the desired concentration when the container is filled with air. The container 23 is advisedly configured as a pouch of inelastic material, and a pressure 16 is arranged to stop the pump drive motor 11 when the container is full. During the calibration, gas from the container is made to flow past the alarm's detectors 28, 33. In such installations where air is sucked from the premises past the detector 28, figure 2, one connects the line 24 from the container directly to the inlet of the intake line 29, and the fixed installation sucks air from the container 23. In a different type of gas alarm, figure 3, one connects the container 23 to the inlet 21 of the pump 10 and lays a second line 30 between the pump's outlet 22 and the detector 33, and allows the pump 10 of the device to blow out gas around the detector. <IMAGE> |
