To adjust a plurality of gas flows having the different molar masses by providing an adjusting device, which prevents the occurrence of large transition flow rates or pressure states in duct lines.
An adjusting device 14A for the specified gas flow of a plurality of analysis gases having the different molar masses is arranged in an analyzing duct line 7. A sending device 9 has a pure gas source, an impurity source 15 and a mixing device 16, which diffuses impurities into the pure gas in the specified pattern. The supplied gas flow to a refining unit 17 is controlled by a mass flow rate adjusting device 18 arranged a supply duct line 8. A mixing means 16 includes a means 19, which divides the gas flow sent from the refining unit 17. The means 19 supplies the gas to a plurality of mixing and diffusing stages 20, 21 and 22, which are arranged in series. A branch pipe 23 of the gas-flow dividing means 19 includes a device 14B for adjusting the specified upstream-side gas pressure of a plurality of the gases having the substantially different molar masses. The structure of this adjusting device 14B is the same as that of an adjusting device 14A.
MAIL ALAIN
MAROT YVES
