Patent ID: 7934413

Claim:
An apparatus for calibrating fluid flowmeters, comprising; (a) a plurality of fluid containers interconnected with conduit piping as a closed fluidic circuit with a flowmeter under test; (b) said closed fluidic circuit being filled with a working fluid; (c) said working fluid having properties appropriate for calibration of the flowmeter under test; (d) said plurality of fluid containers each having a working fluid flow metering piston slidably mounted therein; (e) each of said fluid containers having working fluid inlet ports and working fluid outlet ports located to alternately receive and discharge working fluid on only one side of the working fluid flow metering pistons slidably mounted therein; (f) said working fluid flow metering pistons moving proportionally with working fluid flow in each of the fluid containers in which mounted and moving bi-directionally with directional dependence on working fluid flow into and out of the fluid containers; (g) a means for motivating the working fluid flow through the interconnecting conduit piping and the flowmeter under test and into one portion of the plurality of fluid containers and out of a second portion of the plurality of fluid containers; (h) a means for reversing direction of the working fluid flow relative to the plurality of fluid containers while maintaining unidirectional flow of the working fluid through the flowmeter under test; (i) a means for quantifying a volume of the working fluid displaced by the working fluid flow metering pistons in the plurality of fluid containers during a measured period of time; whereby said apparatus meters and delivers the working fluid flow from a portion of the plurality of fluid containers to the flowmeter under test while receiving back said working fluid flow after passage through the flowmeter under test into a second portion of the plurality of fluid containers.