FLOW RATE CALIBRATION UNIT

PROBLEM TO BE SOLVED: To provide a flow rate calibration unit capable of calibrating a flow rate by replacing a plurality of gas integration units.SOLUTION: A flow rate calibration unit 1 calculates a volume V between flow rate control valves 125A-125C and a second isolation valve 105 by using a pressure fluctuation value per unit time of pressure measurement values measured by a pressure gage 103, with the second isolation valve 105 closed, and a temperature measurement value measured by a temperature gage 104, and calibrates flow rates of mass flow controllers 124A-124C one by one. A first calibration-side connection part 2 for detachably connected to the gas integration unit 20 is provided on an upstream side of the pressure gauge 103. A calibration gas input valve 10, a calibration-side mass flow controller 11, and a calibration-side flow rate control valve 12 that are connected in series are provided in parallel to the second isolation valve 105.SELECTED DRAWING: Figure 1 【課題】複数のガス集積ユニットに付け替えて流量検定できる流量検定ユニットを提供すること。【解決手段】第２遮断弁１０５を弁閉した状態で圧力計１０３が測定する圧力測定値の単位時間当たりの圧力変動値と温度計１０４が測定する温度測定値を用いて、流量制御弁１２５Ａ〜１２５Ｃと第２遮断弁１０５との間の容積Ｖを算出し、マスフローコントローラ１２４Ａ〜１２４Ｃの流量を１個ずつ検定する流量検定ユニット１において、ガス集積ユニット２０に着脱自在に接続する第１検定側接続部２を圧力計１０３の上流側に設け、直列に接続する検定ガス入力弁１０と検定側マスフローコントローラ１１と検定側流量制御弁１２を、第２遮断弁１０５に対して並列に設ける。【選択図】 図１