Online measurement method for effective volume of piston cylinder of piston type gas flow standard device

Abstract

The invention discloses an online measurement method for the effective volume of a piston cylinder of a piston type gas flow standard device. Volume calibration needs to be carried out regularly in apiston type gas flow using period, a laser interferometer is used for measuring the movement distance of a piston, spectral confocal measurement technology measurement and outer diameter measurement are combined to obtain the inner diameter of a piston cylinder, and the effective volume of the piston cylinder is obtained. Therefore, periodic calibration of the volume of the piston cylinder can besimplified, on-line measurement of the volume of the piston cylinder is completed on the premise that the piston cylinder is not disassembled, and the online measurement method has the advantages of being high in measurement precision and convenient to calibrate.

Description

technical field [0001] The invention belongs to the field of gas flow detection, and in particular relates to an online measurement method for the effective volume of a piston cylinder based on a piston-type gas flow standard device. [0002] technical background [0003] At present, the standard device for achieving the minimum gas flow in my country is the pVTt device, which can achieve a minimum flow of 333ml / min. When it detects that the gas flow through the Venturi nozzle is the minimum flow, it takes half an hour, so the pVTt device In the measurement of small flow rate, the smaller the gas flow rate, the longer the test time is required, the test efficiency is low, and the pVTt device can only detect the critical flow Venturi nozzle, which has a single purpose. [0004] Compared with the traditional dynamic volume-time gas flow device, the piston gas flow standard device has the advantages of simple structure and low environmental requirements, and has obvious advantage...

AI Technical Summary

Problems solved by technology

[0012] The contact measurement in the prior art is easy to damage the inner wall of the piston cylinder; the three-coordinate measuring machine can only get the data at both ends of the inner diameter of the piston cylinder, and cannot directly measure the middle part of the piston cylinder, and the evaluation of the inner diameter is unreliable; the three-coordinate measuring machine Measuring the inner diameter needs to collect enough data points for fitting, and the measurement efficiency is low

In addition, the existing effective distance measurement uses a laser interferometer to measure the distance within a fixed time. There is a delay between the time measurement and the laser interferometer, which directly affects the flow value of the piston device.

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