| 摘要 |
PURPOSE:To prevent errors due to change in gas composition by obtaining a sound speed constant based on gas temperature obtained on the low temperature side of a gas flow path and a sound-wave propagating speed, and computing the temperature of a part to be measured based on said constant value and a sound wave propagating time obtained at the part to be measured. CONSTITUTION:In an acoustic type thermometer on the side of high temperature gas, a sound wave from a transmitter 4 is received with a receiver 5, and propagating time is measured with a propagating time measuring device 11. Meanwhile, in an acoustic type thermometer on the side of low temperature gas 3, a sound propagating time between a transmitter 6 and a receiver 7 is measured with a propagating time measuring device 11. The temperature of the gas is measured with a thermocouple 8. A present sound speed constant is computed in a gas-temperature computing device 12. Then, the temperature on the side of the high temperature gas 2 is computed with the gas-temperature computing device 12 by using the sound-wave propagating time obtained on the high temperature side and the sound speed constant obtained on the low temperature side. Then the result is outputted. Even if the gas composition is changed between the starting time and the loaded operation time as with a boiler, the gas temperature on the high temperature side can be measured accurately. |
