Patent ID: 7475586

Claim:
A flow meter calibration apparatus, comprising: a) a calibration cylinder defining a chamber, the cylinder including first and second end caps at axially opposing ends thereof, a first cylinder port adjacent the first end cap and a second cylinder port adjacent the second end cap; b) a piston movable within the cylinder between a first stop position adjacent the first end cap and a second stop position adjacent the second end cap, the piston defining a first and a second chamber portion on opposite sides of the piston, the first and second chamber portions being in fluid communication with the first and second cylinder ports, respectively, regardless of the position of the piston; c) a valve movable between first and second valve positions for alternately directing fluid flow from a supply line to one and separately to the other of the first and second cylinder ports; and d) wherein the volume swept by the piston when moving from one to the other of the first and second stop positions defines a calibration volume, and upon admitting an amount of fluid through a respective cylinder port equal to the calibration volume, further fluid flow into the respective cylinder port is stopped.