Gas small flow standard device

Abstract

The invention discloses a gas small flow standard device. The gas small flow standard device comprises a surge tank, a mass flow controller, a detected flowmeter and a water storage container which are in series connection with each other through pipelines in turn; the water storage container is connected with at least one standard gauge through a pipeline; an air bag or a membrane is arranged in the water storage container; the bottom surface of the standard gauge is higher than that top surface of the water storage container; the air bag or the membrane is provided with a temperature measuring device and a pressure measuring device for detecting the temperature and the pressure in the air bag or the membrane. According to the gas small flow standard device, the structure is simple, the price is low, the measurement accuracy is high, the detection stability is better than 0.1%, and the repeatability is good.

Description

technical field [0001] The invention relates to a gas small flow standard device. Background technique [0002] Gas small flow standard devices mainly include soap film flow standard device, gas bell jar, PVTt method gas flow standard device, m-t method mass flow standard device, piston method flow standard device, standard meter method gas flow device and constant volume gas micro flow rate standard equipment and more. [0003] The soap film flow standard device is one of the traditional gas flow measurement methods. The measurement accuracy of the mechanical soap film is generally lower than 0.5, and the operation is troublesome; the electronic soap film can reach or be better than 0.5. Depending on the size of the soap film tube, the flow rate can range from a few milliliters per minute to several cubic meters per minute. The advantages of this method are simple structure and low investment; the disadvantage is that there is no temperature and pressure compensation, low...

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Problems solved by technology

The standard gauge adopts a necked structure, and the gauge can meet the requirements of second-class standard metal containers. However, due to the direct contact between the measured gas and water, the water evaporates quickly and becomes water vapor into the measured gas. The measured pressure includes Water vapor pressure, if the influence of humidity changes is not accurately measured, it will have a great impact on the measurement accuracy. For example, the measurement results of a flowmeter at the same flow point at 20°C and 30°C may differ by about 1%, which is difficult to meet high-precision requirements. measurement requirements

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