Patent ID: 8505355

Claim:
A bidirectional sphere prover for use with a custody transfer meter for liquids, the prover comprising: a) a straight calibrated section of pipe having a first detector switch proximate a first end and a second detector switch proximate a second end and said straight calibrated section of pipe having a first flange at the first end and a second flange at the second end; b) the straight calibrated section of pipe being free of flanges, lateral openings and elbows between the first detector switch and the second detector switch; c) the straight calibrated section of pipe defining a tubular interior surface coated with a corrosion inhibitor; d) the first end of the straight calibrated section of pipe being connected to a first U-tube conduit being connected to a first elbow being connected to a first launch tube; e) the second end of the straight calibrated section of pipe connected to a second U-tube conduit being connected to a second elbow being connected to a second launch tube; f) a resilient single sphere moving back and forth from the first launch tube, through the first elbow, the first U-tube conduit the straight calibrated section of pipe, second U-tube conduit, the second elbow to the second launch tube in response to actuation of a 4-way valve; and g) the resilient single sphere being in sealing contact with the coating of corrosion inhibitor on the tubular interior surface of the straight calibrated section of pipe.