Encyclopedia of standard gas preparation methods
Release time: 2021-06-23 11:09:38
Source: Yuejia Gas
Author: Xiaoyue
Reading volume:
Standard gas preparation methods include: weighing method, permeation method, partial pressure method, diffusion method, volume method, saturation method, flow method, dilution method, volume method, etc. The main purpose of the standard gas is to calibrate and calibrate, so the accuracy requirements are relatively high. The production of standard gas must have the relevant national certification, and the enterprise's certification is a second-level standard material. There is also the National Standards Center.
Weighing method
1. Scope of application: The weighing method is a method recommended by the International Organization for Standardization. It is only suitable for gases that do not react between the components, the components and the inner wall of the gas cylinder, and the condensable components that are completely in the gaseous state under the experimental conditions .
2. Equipment required: gas distribution equipment: vacuum pump, vacuum gauge, high and low pressure gauges, valves, gas cylinder fixtures, and chassis. Weighing equipment: high-precision balance.
Infiltration method
1. Scope of application: The permeation method is suitable for the preparation of trace amounts of active gas. It is a dynamic gas distribution method.
2. Equipment required: gas distribution equipment: permeation pipe, pressure regulator valve, steady flow system, flow meter, temperature recording instrument, valve, pipeline, mixing tank.
Partial pressure method
1. Scope of application: The partial pressure method is suitable for preparing standard mixed gases with a content of 1~60% that are gases at room temperature.
2. Equipment required: gas distribution equipment: gas cylinder bus bar, pressure gauge, valve, vacuum pump, pipeline, gas cylinder fixture.
Diffusion method
1. Scope of application: the diffusion method is suitable for the preparation of organic gases that are liquid at room temperature
2. Required equipment: gas distribution equipment: gas cylinders, valves, flow control valves, flow meters, liquid components, analytical instrument cylinders, fixtures.
Volume method
1. Scope of application: The static volume method is suitable for the preparation of a variety of small and small amounts of standard gases in the laboratory, and the pressure is close to atmospheric pressure.
2. Equipment required: gas distribution equipment: gas cylinders, gas cylinder pressure reducing valves, fixed-volume pipes, pressure gauges, and vacuum pumps.
Saturation method
1. Scope of application: The saturation method is suitable for gas and steam that are easy to condense.
2. Equipment required: gas distribution equipment: gas cylinders, gas cylinder pressure reducing valves, condensers, saturators, thermostats, pressure gauges, circulating fans.
Flow method
1. Scope of application: The flow ratio method is a dynamic gas distribution method that strictly controls the flow of a certain proportion of the component gas and the release diluent gas, and is a standard gas obtained by mixing.
2. Equipment required: gas cylinders, gas cylinder pressure reducing valves, one-way valves, flow controllers, pressure gauges, pipes, and chassis.
Dilution method
1. Scope of application: Dilution method is one of the methods for preparing low-content standard gas.
2. Equipment required: gas cylinders, gas cylinder pressure reducing valves, flow controllers, pressure gauges, pipelines.
Volume method
1. Scope of application: The volume ratio method is a simple gas distribution method, which is calculated by volume according to the content of the required gas. The standard gas is obtained by controlling the volume of the component gas and the diluent gas after mixing.
2. Equipment required: syringes, fixed-volume containers.