Patent WO-2013180427-A1 (WO)
Title: Gas flow meter program of constriction device and flow measurement method and flow measurement device using same
Inventor: YOON JUNG JOONG
IPC: G01F15/00
Filed: 2013-05-27
Abstract: The present invention relates to: a method for measuring the flow of a gas using a method for simply correcting the gas expansion coefficient and coefficient of runoff by calculating the adiabatic index, the vapor density, and the viscosity coefficient in a gas flow meter using a constriction device by using a thermodynamic expression and an arrangement function, and then obtaining the adiabatic index, the gas density, and the gas viscosity coefficient corresponding to each temperature and pressure condition; and to a program for same and to a flow measurement device. The present invention provides a gas flow measurement method comprising: a process in which the type, temperature (T), pressure (P), and pressure difference (dP) of gas for which flow is to be measured, and the entrance diameter (D) and the throat diameter (d) of the flow measurement device of a constriction device are input; a process in which input constants according to the type, temperature, and pressure of the gas are selected and inputted from an input constant (adiabatic index k, gas viscosity μ, and gas density ρ<sub/>value) database according to the type of the predetermined gas; a process in which an expansion coefficient (ε) is calculated using the input adiabatic index (k), diameter ratio (β), and pressure ratio (τ); a process in which the coefficient of runoff (C) is corrected; and a process in which the calculated expansion coefficient, the corrected coefficient of runoff, and the pressure difference, the throat diameter, the diameter ratio, and the gas density are substituted in a gas flow measurement formula and calculated. The present invention also provides a gas flow measurement method comprising: a process in which the coefficient of runoff is corrected; a process in which a certain preset coefficient of runoff is inputted; a process in which a gas flow is set by a calculation process according to a gas flow measurement formula; a process in which Re is set through a calculation process according to an Re calculation formula; a process in which the coefficient of runoff is corrected again through calculation according to the coefficient of runoff calculation formula; and a process in which the correction process is repeated 2 to 10 times. The present invention also provides a gas flow measurement method comprising a process in which, in the input constant inputting process, interpolation or extrapolation is used to calculate and input the input constants from the input constant (adiabatic index k, gas viscosity μ, and gas density ρ<sub/>value) database according to the type, temperature, and pressure of the gas. The present invention also provides a gas flow measurement method in which: the above processes include a process in which the content ratio, of various types of mixed gases for which flow is to be measured, is measured and inputted; and which comprises a process in which a single input constant is extracted through calculation using the inputted content ratio and input constants of the gases to be measured. The present invention also provides a gas flow measurement program formulated from the gas flow measurement method using programming language. The present invention also provides a gas flow measurement device comprising: an information processing device (60) including a gas flow measuring body (10) and a pressure sensor (20), a temperature sensor (30), a pressure difference sensor (40), and a display unit (50) mounted and provided on the body, and having the gas flow measurement program loaded therein; and a preset input constant database (70) capable of being used in the gas flow measurement program. The present invention also provides a gas flow measurement device in which a gas selection unit and a function selection unit are further added to the information processing device.