| 摘要 |
Device for determining variations within an indicator tube having a material which varies in light intensity or color in the presence of particular gases, comprises a first set of light barrier devices as light sources and photoelectric cells on respective sides of the tube. A reference set of light barrier means is provided for sensing a reference value of light through the tube and is connected to a comparator for sensing the variations between it and the first set of light barrier tubes and for recording this information on a counter. The counters are connected to a time signal transmitter and time signal receiver and the predetermined variations which occur at various time intervals are picked up by an indicator or alarm circuit designed to show the variations and indications which are sensed in a particular time period. A method of gas measuring and warning using the light barriers disposed at spaced locations along the lengths of the indicator tube which has the substance therein which varies in light intensity or color, in accordance with the gas of a preselected type which is detected, when passed through the material therein, comprises converting the intensity of the light which is passed through the tube at the locations of the barriers into a logic signal, alternately storing the logic signals into two separate counters, periodically sensing the difference of the values in the counters, and using the sensed difference to start a time signal transmitter and time signal receiver. The time signal is monitored so that a new difference of the counters operates an alarm. The reciprocal of the value of the time signal sensed by the receiver may be used as an indication of the gas concentration. |
