Patent ID: 7424895

Claim:
A measurement system for measuring a rate of flow through a flow controller that can be operatively coupled to a fluid distribution system downstream of the flow controller, the measurement system comprising: an inlet; a pressure sensor operatively coupled to the inlet; a valve operatively coupled to the inlet downstream of the pressure sensor; a chamber having a known internal volume and operatively coupled to the valve downstream of the valve; and a choking orifice operatively coupled to the inlet upstream of the pressure sensor; the choking orifice having a choked position; wherein, when the inlet of the measurement system is operatively coupled to the fluid distribution system, the measurement system: collects first rate of pressure rise data pertaining to the chamber during a first interval in which the choking orifice is in the choked position and the rate of flow is sufficient that the pressure upstream of the choking orifice is approximately twice that of the pressure downstream of the choking orifice; calculates a first rate of flow through the flow controller based upon the first rate of pressure rise data, and the known internal volume of the chamber; and determines the measured rate of flow through the flow controller based upon the calculated first rate of flow.