| 摘要 |
PURPOSE:To achieve a stable detection, by keeping constant a flow rate in a leakage detector. CONSTITUTION:An atmosphere gas surrounding a sampling piping 9 is always sampled to sent to an ionization detector 20. The detector 20 ionizes a sodium particle in the gas by a filament and a number of the sodium particles in the gas is known from a condition of ionized electric current. A flow rate of the gas flowing in the detector 20 is controlled by a valve 25 and used sampling gas is sent to a pump 11 through a filter 26 and then, is returned to a housing receptacle. Further, a throttle 30 restricting the gaseous flow rate is provided on the rear stage of a leakage detector 20 and a by-pass pipe 31 is connected in parallel. Decrease of Na concentration in a detection piping is prevented by regulating the gaseous flow rate in the director 20 to 3- 5l/min. and also, regulating the flow rate in the pipe 31 to 15-50l/min. and then, increasing the flow rate in the detection piping of detection side 5-10 times the flow rate in the leakage detector. |
