Method of Measuring Critical Flow Venturi Nozzle with Piston Gas Flow Standard Device

This paper introduces a method of testing critical flow venturi nozzle with piston type gas flow standard device. The traditional testing methods for critical flow venturi nozzle are divided into real flow verification method and geometrical verification method. The existing real flow verification method is generally carried out on pVTt gas flow standard device. By comparing the two testing methods from the aspect of testing principle, it is found that it is feasible for the device to transmit volume to the nozzle through uncertainty analysis, The test result of nozzle of piston gas flow standard device and the test result of pVTt method are verified, and the EN value meets the requirement. The piston-type gas flow standard device is used to transmit the nozzle volume, which greatly improves the efficiency of nozzle volume transmission. When there are problems such as misalignment or incomplete sealing during nozzle clamping, it can be found quickly; However, due to the limited cylinder size and motor speed of the piston unit, its flow is limited and it is impossible to measure nozzles with excessive flow.