Apparatus for determining the characteristic of a flowmeter.

摘要

A fluid displacement measuring cylinder has near its ends, respectively, an inlet and an outlet. A fluid displacement measuring piston is adapted to travel through the measuring cylinder as a fiuid barrier. A control piston having first and second sides is adapted to travel through the control cylinder as a fluid barrier. A rod connects the control piston only to the side of the measuring piston facing towards one end of the measuring cyilnder. A gas pressurized plenum chamber is connected to try control cyclinder so the force of the gas pressure urges the measuring piston toward the other end of the measuring cylinder. The movement of the measuring piston through the measuring cylinder is sensed and the movement of tne control piston tnrough the control cylinder is fluidically controlled. The pressure in the plenum chamber, which has a substantially larger volume than the control cylinder is selected so as to cancel the force imbalance caused by the rod.