Patent ID: 7376520

Claim:
A gas flow rate verification apparatus, comprising: a first volume defined within a first chamber; a second volume defined within a second chamber, the second volume being larger than the first volume, wherein the second volume is isolatable from the first volume by at least one valve; a first pressure measurement device configured to be connected in fluid communication with either the first volume, the second volume, or both the first and second volumes; and a second pressure measurement device configured to be connected in fluid communication with either the first volume, the second volume, or both the first and second volumes, the second pressure measurement device capable of measuring higher pressures than the first pressure measurement device, wherein each of the first volume, the second volume, or both the first and second volumes is selectable as a test volume for measuring a gas flow rate, wherein each of the first pressure measurement device or the second pressure measurement device is selectable for measuring a pressure within the test volume.