Patent ID: 9506801
Filing Date: 2016-11-29
CPC Classification: G01F

Claim Text:
1. A piston prover comprising a measurement cylinder having an upstream end and a downstream end; a hydraulic cylinder coupled with a side of the downstream end of the measurement cylinder; a measuring piston that moves through a predetermined distance from an upstream side toward a downstream side through the measurement cylinder during measurement due to a fluid flown from the upstream end to eject a reference volume of fluid; and a piston rod that is movably accommodated in the hydraulic cylinder, and having the measuring piston and the piston rod separately constructed, wherein measurement standby position stop means that stops the measuring piston at a predetermined upstream measurement standby position is included, and when returning the measuring piston to the predetermined measurement standby position, the piston rod moves the measuring piston from the downstream side to the upstream side and the measurement standby position stop means stops the measuring piston at the predetermined measurement standby position, after which only the piston rod is caused to move from the upstream side to the downstream side and is accommodated in the hydraulic cylinder.