Gas distribution method and gas distribution device for checking SF6 (sulfur hexafluoride) analyzer

Abstract

The invention provides a gas distribution method and a gas distribution device for checking an SF6 (sulfur hexafluoride) analyzer. The gas distribution method comprises the following steps of mixing SF6 gas and sample gas under the control of mass flow controllers, and thinning the concentration of the sample gas; mixing the thinned sample gas and the SF6 gas under the control of the mass flow controllers, and thinning the concentration of the sample gas for the second time; mixing the sample gas after second time of thinning and the SF6 gas under the control of the mass flow controllers, and thinning the sample gas for the third time. The gas distribution device is characterized in that a pressure relief valve, a first mass flow controller, an electromagnetic valve, a first static mixer, a second mass flow controller, a second static mixer, a third mass flow controller and a third static mixer are sequentially arranged at the end, connecting with an SF6 gas cylinder, of a main gas path; the SF6 gas cylinder is connected with the input end of the second static mixer through a fourth mass flow controller, and is connected with the input end of the third static mixer through a fifth mass flow controller; each sample gas cylinder is respectively communicated with a main gas path through a branch pipeline, and a sixth mass flow controller and the electromagnetic valve are arranged on the branch pipeline.

Description

technical field [0001] The invention provides a gas distribution method and a gas distribution device for calibration of a sulfur hexafluoride analyzer, specifically referring to a method and a device for preparing a low-concentration standard gas by adopting a three-stage dilution technology. Background technique [0002] Sulfur hexafluoride gas has good insulation and arc extinguishing properties, and has been widely used in gas-insulated electrical equipment. In recent years, with the operation of UHV AC / DC substations, a large number of high-voltage sulfur hexafluoride electrical equipment has been included in the daily technical supervision work, and now most of them use SF 6 Gas decomposition product meter, SF 6 Implementation of SF by gas purity meter, etc. 6 Quality supervision of electrical equipment. [0003] In order to ensure the measurement accuracy of the instrument, the above-mentioned instruments need to be calibrated regularly. At present, the gas distrib...

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Problems solved by technology

[0003] In order to ensure the measurement accuracy of the instrument, the above-mentioned instruments need to be calibrated regularly. At present, the gas distribution instrument is mostly used in the laboratory to prepare the standard gas to SF 6 Analyzer calibration, the existing gas distribution technology has the following problems: the most advanced gas distribution instrument currently controlled by a mass flow meter has a maximum single-channel ratio (volume ratio) of up to 1:70, the lowest gas concentration (volume ratio) that can be prepared ratio) is 14286ppm, and the minimum concentration of the calibration gas required for calibration of the sulfur hexafluoride decomposition product instrument in the laboratory is 2ppm. Therefore, in the actual calibration process, a calibration gas with a concentration of about 50ppm is first prepared in the steel cylinder by the syringe quantitative method 1 , after being quantified by the chromatograph; then, use the standard gas 1 as the gas source, and prepare a 2ppm standard gas with the aid of a gas distribution device. This method has problems such as cumbersome operation, low efficiency, high accuracy, and easy introduction of other impurities. There is an urgent need for a gas distribution technology with convenient operation, high gas distribution efficiency and good accuracy

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