OFFICIAL APPROVAL SYSTEM OF GAS PIPING SYSTEM

摘要

PROBLEM TO BE SOLVED: To approve the flow rate of a mass flow controller officially and precisely by using a real process gas. ;SOLUTION: In gas lines 23A, 23B, cut off valves 25A, 25B, mass flow controllers 27A, 27B and cut off valves 29A, 29B are provided from an upper stream side respectively and joined and a pressure sensor 11 is installed there and then reach a process chamber 37 through the cur off valve 21. When the cut off valve 21 is closed after exhausting once the installation position of the pressure sensor 11 and the cut off valve 25A is opened, the indication value of the pressure sensor 11 is increased by the flow in of a process gas A and a flow rate is approved officially by the increase speed. The leak from the cut off valve can be approved officially by the change of the indication value of the pressure sensor 11 when the installation position of the pressure sensor 11 is held in an air tight state.;COPYRIGHT: (C)1997,JPO