Research Of The Electrical Driving Double Pistons Gas Prover

Piston gas prover is a gas prover which belongs to volumetric method. Itsadvantages are high precision, stable flow, adjustable working pressure, fastmeasuring speed and high efficiency of automatic control. In order to solve theproblem that piston prover’s maximum calibration flow is limited by the pistoncylinder volume, a double-piston gas prover which is now used for the calibration ofcritical flow meters was developed. The prover’s two pistons run alternately andgenerate continuous standard flow. It breaks the restriction of cylinder volume, thenincreases piston prover’s maximum calibration flow.Firstly, summed up and analyzed the piston prover’s research status and it waslack of study of piston device with double working chambers up to now. Secondly,put forward the device’s overall design scheme and mechanical structure, andestablished its corresponding calibration mode. The prover is based on active pistonand negative-pressure method. It has two piston cylinders and the control system iscombined by PLC and LabVIEW. Then based on Simulink, the process which twopistons move together was studied. Finally, according to the requirements of thecalibration, the control system was completed: synchronization control of the twoaxes realized by PLC is the core of lower machine; the upper machine’s functions areprocess monitoring, data processing and so on.After completing the device, a series of experiments and uncertainty assessmentwere done. The experimental results show that the prover’s repetitiveness is less than0.02%. In comparison with the piston standard facility in Zhejiang Institute ofMetrology which based on balance adjustment principles, the results show a goodagreement. The electrical driving double-piston gas prover which uses a newworking principle and has innovations in design ideas is feasible cetified byexperiments.