| 摘要 |
PURPOSE:To eliminate the change of characteristics of gas due to the pressure change of standard gas when the temperature is changed by controlling the volume changeable part in accordance with the pressure of measured gas vessel, which is connected to the vessel filled by the standard gas. CONSTITUTION:A pair of sound pipes 22, 23 is arranged nearly in the constant temperature oven 21. The measured gas is introduced from a pipe 25 and is exhausted from an exhaust pipe 42 to atmosphere after flowing through the sound pipe 22. The standard gas is filled in the other sound pipe 23. The pressure difference between pipes 22, 23 is detected by the pressure difference detector 41 and the motor 45 is driven in accordance with this pressure difference signal. The pressure is controlled to be equalized by changing the volume of a bellows 44. On the other hand, the standing sound waves in accordance with the distances l1, l2 given by microphones 28, 31, speakers 29, 32 and amplifier 30, 33 and the speeds of sound of the measured gas and the standard gas are conducted to a recorder 36 via a mixing detector 34 and a frequency-voltage convertor 35. And the total quantity of calorific value and the specific gravity of the measured gas is identified. By these, the accuracy of measuring characteristics of gas can be improved. |
