Method and device for calibrating flow coefficient of orifice plate by adopting pressure method

Abstract

The invention discloses a method and a device for calibrating a flow coefficient of an orifice plate by adopting a pressure method, and the method comprises the following steps: measuring the pressure change to obtain the relationship between multiple groups of pressure and flow, and further fitting the slope and intercept of a flow coefficient function expression. The device comprises a feeding container, a feeding slow pressure tank, a pressure stabilizing tank and a receiving container which are sequentially communicated through a vacuum pipeline, a valve is arranged at an outlet of the feeding container, an electric pressure regulating valve is arranged between the feeding slow pressure tank and the pressure stabilizing tank, and a pore plate is arranged in the vacuum pipeline between the pressure stabilizing tank and the receiving container. According to the invention, mass weighing is not needed; the number of test points is not limited by the number of collection containers in a weighing method, and the test points can be freely increased; the flow coefficients of pore plates with different pore diameters can be measured by adjusting the volume V of the gray area, and the calibration range of the pore plates is wide; the influence of weight error of the weighing and receiving container is avoided; and the potential safety hazard of excessive gas collected by the material collecting container is avoided.

Description

technical field [0001] The invention belongs to the field of test and calibration of gas flow, in particular to a method and a device for calibrating the flow coefficient of an orifice plate by a pressure method. Background technique [0002] In a vacuum system, it is usually necessary to stably pass a certain amount of gas into the vacuum pipeline. The gas flow control needs to be realized by installing an orifice plate with a certain aperture, and the gas flow rate passing through the orifice plate in a certain period of time is calculated by the orifice plate flow formula. The orifice flow formula is a linear function expression related to the pressure in front of the orifice. The flow coefficient of the orifice plate is obtained by linear fitting of the data corresponding to the flow rate of multiple pressure points, and the slope and intercept of the linear function expression are obtained, which are used to determine the gas flow value in the subsequent use of the ori...

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Problems solved by technology

[0003] However, the following problems exist in the process of calibrating the flow coefficient of an orifice plate with a large or small diameter using the conventional weighing method: (1) the diameter of the orifice plate is too small, the gas flow through the orifice plate is small within a certain period of time, and the weighing The weighing deviation of the container loaded with gas during the weighing process seriously affects the accuracy of the gas weighing data; (2) The diameter of the orifice plate is too large, and the pressure in the container loaded with gas during the weighing process is too high, which exceeds the acceptable range of the container, posing a safety hazard , making the method difficult to implement

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