Development of a reciprocating double-pistons gas prover

Piston prover is widely used as a standard gas flow device for its advantages of high accuracy in standard volume, flow stability and repeatability. The applications of the conventional piston provers are limited by the maximum calibration flow generated by the piston cylinder volume. In the current paper, a reciprocating double-pistons gas prover was proposed, which can provide a continuous standard flow to calibrate meters like critical nozzles and so on. There are two pistons within the proposed prover, which could be operated in three modes: single-piston mode, double-pistons parallel mode and double-pistons reciprocating mode. The working mechanisms of all three modes were presented and the mathematical model was also introduced, especially for the double-pistons reciprocating mode. Then experiments were carried out to validate the new calibrating method; it is shown that the proposed reciprocating double-pistons gas prover is capable of precisely calibrating gas flow meters. Comparisons between the experimental results and data obtained using the piston prover based on the balance adjustment principle are also presented.