Patent ID: 8646307

Claim:
A mass flow controller verifying system for use in a gas piping system provided with one or a plurality of influent flow gas lines each having a mass flow controller and provided with a pre-diverting flow gas line which is before gas lines including the influent flow gas lines are diverting and wherein the pre-diverting flow gas line is provided with a pre-diverting valve thereon, said verifying system comprising: a verifying gas line provided with a flow rate measurement unit adapted to measure a flow rate of a gas, a flow rate adjustable valve by which an opening degree thereof is adjusted so that the measurement flow rate measured by the flow rate measurement unit is coincident with a set flow rate, and a pressure measurement unit adapted to measure a gas pressure, wherein the verifying gas line is arranged in parallel to the influent flow gas lines and connected to the pre-diverting flow gas line; a reference volume calculating portion adapted to calculate a reference volume based on time series data of a measurement pressure measured by the pressure measurement unit, wherein the reference volume is a volume inside a piping portion determined by the flow rate adjustable valve, a closing position of each of the influent gas lines and the pre-diverting valve, in a state that each of the influent gas lines is closed and the pre-diverting valve is closed; a verifying parameter calculating portion adapted to calculate a verifying parameter based on the time series data of the measurement pressure measured by the pressure measurement unit in a state that the influent gas lines, except for an influent gas line having a target mass flow controller to be verified, are closed at the same position as the closing position in the calculation of the reference volume, and the flow rate adjustable valve and the pre-diverting valve are closed; and a comparing portion adapted to compare a reference parameter set based on the reference volume and the verifying parameter.