Variable medium positive pressure method gas flow standard device

Abstract

The invention relates to the technical field of gas flow standard devices, and discloses a variable medium positive pressure method gas flow standard device which comprises an air compressor and a high-purity compressed gas tank, the air compressor is connected with a gas purification device through a pipeline, and the gas purification device is connected to one end of a gas storage tank through a pipeline; and the high-purity compressed gas tank is connected to the other end of the gas storage tank through a pipeline. The standard flow meter of the variable medium positive pressure method gas flow standard device is in positive pressure, the pressure is adjustable, and the detected flow meter works at normal pressure; according to the variable medium positive pressure method gas flow standard device, the temperature of a medium is stabilized by adopting a heat exchanger and a constant-temperature water bath box, and coefficient compensation is carried out on a standard flow meter in the pressure adjusting process; and the output end of the detected flowmeter is further connected with a vacuum pump through a pipeline, and the vacuum pump not only improves the pressure ratio, but also enlarges the flow range of the detected flowmeter.

Description

technical field [0001] The invention relates to the technical field of gas flow standard devices, in particular to a variable medium positive pressure method gas flow standard device. Background technique [0002] A gas flow meter is an instrument for measuring gas flow, which is installed in a pipeline to record the amount of gas flowing through it. After long-term use, the gas flowmeter will inevitably have measurement errors. At this time, it is necessary to use a gas flow standard device to verify or calibrate the gas flowmeter. [0003] However, in practical applications, we found that the traditional gas flow standard device still has some shortcomings, such as: [0004] 1. Most of the gas flowmeters are used in the positive pressure state. The working pressure of the flowmeter is higher than the local atmospheric pressure. However, most of the traditional gas flow standard devices are negative pressure gas flow standard devices. The flow rate used in the positive pre...

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Problems solved by technology

[0004] 1. Most of the gas flowmeters are used in the positive pressure state. The working pressure of the flowmeter is higher than the local atmospheric pressure. However, most of the traditional gas flow standard devices are negative pressure gas flow standard devices. The flow rate used in the positive pressure state The meter can only be verified or calibrated with the negative pressure method gas flow standard device, and there is a phenomenon that the verification or calibration conditions are inconsistent with the actual working conditions, which may easily cause the flow value to be inaccurately reproduced;

[0005] 2. For gas flow meters with large pressure loss, the inlet pressure of the tested flow meter must be above 0.2MPa ~ 0.5MPa to work normally, and the current gas flow standard device cannot be used;

[0006] 3. In the current gas flow standard device, the working pressure of the tested flow meter and the standard flow meter are basically the same, either they all work in a positive pressure state, or both work in a normal pressure state, and the scope of application of the gas flow standard device is relatively small;

[0007] 4. The current gas flow standard devices can only use a single medium as the detection working medium (such as air), and the medium used in the actual working condition of the gas flowmeter is not only a medium of air. For this type of flowmeter Gas flowmeters using various media in actual working conditions can only be tested with air flow standard devices, and the inconsistency of the detection media will lead to inaccurate flow values

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