炭鉱坑内用電気式温度計の研究
1986 年 102 巻 1175 号 p. 15-20
詳細
1986 年 102 巻 1175 号 p. 15-20
As widely known, an inadvertent break or make of a live circuit or poor connections in the circuit of any electric instrument may touch off a fire in underground coal mines unless both the voltage and the current in the circuit are small enough. A built-in battery, whenever it is implemented, may well be capable of igniting the inflammable gases when its terminals crash. JIS type 006P battery or an equivalent, however, is conceived to be satisfactorily a safe power source when it is engaged with micropower electric thermometer circuit systems with semiconductor temperature transducer. Due to the laminated construction of manganese elementary dry cells in this type of batteries, the internal resistance is fairly high, so it consequently suppresses the intensity of the short circuit current within a safe extent.This paper discusses the basic consideration of the power circuits of the new electric thermometers from the point of view of the gas inflammability.The compatibility of temperature transducers which assort with several versions of the thermometer circuitry is also described accompanying with a tabulation. Integrated, semiconductor, terr, ierature-transducing devices of the electric current output mode are regarded as competent for use in underground coal mines.Although both the thermal resistance and the thermal capacity of the transducer alone are very small, the effective time constant depends on the thermal properties of the protecting sheath, so that the time response of the transducer, in several media is almost the same to that of conventional alcohol thermometers.
