| 摘要 |
PROBLEM TO BE SOLVED: To reduce a consumption amount of a reference gas used in the calibration of a gas purity meter. SOLUTION: A constituent device 14 is provided to the gas cooling system of a dynamo. A calibration piping system is constituted as a closed pipeline by the constituent device 14, distribution pipes 12 and 13 and the gas purity meter 2 of the dynamo and atmospheric discharge is also enabled through an atmosphere discharge pipe 7. At the time of setting of a reference point, the reference gas is allowed to flow through the gas purity meter 2 of the dynamo and a calibration gas purity meter 15 and discharged to the atmosphere by opening a valve 17. When the measured value of the gas purity meter 15 becomes the density of a reference point gas, the valve 17 is closed while a valve 33 is opened to stop the supply of the gas from a reference gas cylinder 3 and a fan 16 is operated to circulate the reference point gas to the purity meters 2 and 15. The flow rate of the gas is controlled constant by the fan 16 and the pressure of the gas is controlled so as to become the highest use pressure or below of the purity meter 15. The flow rate of the reference point gas becomes constant and, when the calibration gas purity meter 15 continues the concentration of 100% of the reference gas for a constant time or above, the reference point of the gas purity meter 2 of the dynamo is set. COPYRIGHT: (C)2006,JPO&NCIPI
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