Instruments and Systems: Monitoring, Control, and Diagnostics Annotation << Back The equation of gas expansion factor for the standard diaphragm DAEV ZH.A. This paper discusses the problems of the influence of the speed of sound on the processes of expansion of natural gas for the primary device for measuring the flow rate and quantity of natural and petroleum gas. The equation for the correction factor takes into account the expansion of the gas behind the diaphragm, which is expressed through the speed of sound (Mach number). Characteristics are constructed for the coefficient of expansion of the standard aperture of the new equation. In this paper made a comparative analysis of the existing equation and expressed through the speed of sound. The equations for calculating the relative standard and expanded uncertainties of the correction factor on the extension of the standard diaphragm. Recommendations on the use of the equation when measuring the flow rate and volume of natural gas through the nozzles. Keywords: orifice plate, flow, differential pressure, nozzle, gas, Mach number. Contacts: E-mail: zhand@yandex.ru Pp. 50-52.