Standard gas industry term for lead gases. Standard gases are standard substances of gases, also known as calibration gases, calibration gases, Standard Gases, Reference Gases, etc. Standard gas is a highly uniform, stable and accurate measurement standard, so standard gas must have the basic role of reproduction, preservation and transmission of values, used in physical, chemical, biological and engineering measurement fields to calibrate measuring instruments and measuring processes, evaluate the accuracy of measurement methods and test laboratory detection capabilities, determine the characteristics of materials or products, and conduct quantitative arbitration.
Standard gases include binary, ternary and multidimensional standard gases.
application field
1. Common standard gases include: gas alarm standard gases, power energy standard gases, petrochemical standard gases, environmental monitoring standard gases, medical and health standard gases, instrument standard gases, etc.
2. The standard gas can also be used for environmental monitoring, toxic organic matter measurement, automobile emission gas testing, natural gas BTU measurement, liquefied petroleum gas calibration standards, supercritical fluid technology, etc. Standard gas is divided into binary, ternary and multidimensional standard gas according to the number of components; gas registration accuracy requirements are characterized by gas distribution tolerance and analysis tolerance; SE 2MI gas distribution tolerance standard is more common, but each company has enterprise standards. The ** concentration of the components is 10 grades, and the number of components can reach more than 20 species. The preparation method can be gravimetric method, and then verified by chromatographic analysis, or can be transmitted according to standard transmission formula.
3. Large ethylene plants, ammonia plants and other petrochemical enterprises need dozens of pure gases and hundreds of multi-component standard mixtures during start-up, shutdown and normal production of the unit, which are used to calibrate and calibrate the online analytical instruments used in the production process and to analyze the quality of raw materials and products.
scope of application
1, for gas product quality control
2, used for instrument verification and calibration
3, for air pollution monitoring
4, for medical care and clinical testing
5, for building home environment monitoring
6. Establish traceability of measurement
7. Ensure accurate and consistent measurement results
8. Transfer of magnitude
9. Promote the development of measurement technology and quality supervision
Homogeneity is an important index for evaluating the performance of standard gases. The characteristics of a standard gas should be uniform, i.e., its magnitude should remain constant within a specified range. No matter which method is used to prepare the standard gas, it needs to be mixed. Standard gas mixing methods include: heat treatment method, cylinder rolling method, special filling method, natural diffusion method, other mixing methods, etc.
A reference material is a substance or material that is sufficiently homogeneous and has one or more well-defined characteristics for use in calibrating instruments, evaluating measuring methods, or determining the magnitude of a substance. Standard gas is a gas standard substance. Because standard gas has a certain validity period, the stability of standard gas is a key problem in the preparation and use process.
It is well known that an important condition for standard gases packed in high-pressure containers (cylinders) is that their values should not change during storage and use. In fact, the standard gas component gas or impurity in contact with the inner wall of the container often cause adsorption, desorption, chemical reaction and other phenomena, and make its value change with time, the lower the content, the more complex the composition, the greater this change.
In the research, development and production of automatic fire alarm, respirator, sensor and rapid detection instrument of inflammable, explosive, poisonous and harmful gases and other fire fighting products, it is often necessary to prepare a series of standard gases for testing and calibrating products.
In the investigation of fire cause, when studying and applying a method of analyzing and identifying gas evidence, it is necessary to prepare standard gas of certain concentration of detected substance to test the sampling efficiency of different sampling instruments or the absorption efficiency of different absorption solutions and the accuracy and reliability of identification method. Therefore, the preparation of a certain concentration of standard gas is an important link in the research, development, production and fire protection of fire products. The preparation of standard gas is different from that of liquid standard material, which has certain difficulty. Therefore, this paper will focus on introducing several kinds of instruments used, simple equipment, easy to operate, especially suitable for the development of fire protection products, production and fire protection practical work of standard gas preparation technology.
Standard gas refers to the standard reference material of gas state, including high purity standard gas and mixed standard gas. Gas distribution mainly refers to the preparation of mixed standard gas. A mixed standard gas is made by mixing a known amount of one or more components of a gas with a background gas that does not react with it. Standard gas preparation technology mainly includes static gas distribution technology and dynamic gas distribution technology.
What is the quality of the standard body in the process of research, and how poor it is in the method of analysis and comparison? what is the quality of the standard body in the period of validity and the effect after the reduction of the force in the bottle? both need to be judged by uncertainty. Because the degree of uncertainty is the indicator of the research level of the standard standard, it is the basis for determining the quality of the standard system.
The definition of standard uncertainty is defined as quantitative uncertainty. In general, it refers to the uncertainty of the measurement results. It can also be understood as a parameter of the measurement results, which is used to represent the dispersion of the values to be estimated reasonably. The measurement uncertainty generally consists of several grades, some of which can be determined by the statistical score of the results of the measurement series, and according to the actual standard.
Deviation is also regarded as Class A component, Class A determination or Class A uncertainty; other components can also be represented by standard deviation, which is estimated based on the probability score of experience or other information, and is regarded as Class B component, Class B determination or Class 8 inaccuracy. while the expansion of the degree of uncertainty is like giving more two-digit valid numbers, the inaccuracies in the inter-calculation can be taken more. In practical work, we can often get a meaningful measurement result by understanding the concept of uncertainty and correctly using the method of estimating uncertainty.
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