| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a flow rate calibration method of flow rate controller by a build-up (or ROR) method which can be more rapidly performed with high precision by a downsized calibration unit. <P>SOLUTION: A calibration unit 5, which comprises a build-up tank BT, on-off valves V<SB POS="POST">1</SB>, V<SB POS="POST">2</SB>, a temperature detector Td, and a pressure detector Pd, is branchedly connected to a gas supply passage L, and the on-off valve V<SB POS="POST">2</SB>is connected to a vacuum evacuation device. At first, respective on-off valves Vo<SB POS="POST">1</SB>to Vo<SB POS="POST">n</SB>of flow rate controllers and an on-off valve Vo at a gas usage part are closed and the on-off valves Vo<SB POS="POST">2</SB>, Vo<SB POS="POST">1</SB>are opened. Then, only an on-off valve of a flow rate controller to be calibrated is opened to allow a set flow rate of gas to flow into the calibration unit 5, and at a time t<SB POS="POST">0</SB>gas temperature and gas pressure in the tank are measured. Thereafter, the on-off valve V<SB POS="POST">2</SB>, is closed and build-up of the gas in the tank BT is carried out. At a time t<SB POS="POST">1</SB>the on-off valve V<SB POS="POST">1</SB>is closed, and at a time t<SB POS="POST">2</SB>gas temperature and gas pressure are measured. Then, a flow rate of gas Q is calculated from measured values and flow rate calibration is performed by comparing the set flow rate of gas with the calculated flow rate of gas Q. <P>COPYRIGHT: (C)2012,JPO&INPIT |
