1、 Weighing method

1. Scope of use

The weighing method is recommended by the International Organization for Standardization. It is only applicable to the gases between components, which do not react with the inner wall of the cylinder, and the condensable components which are completely in the gaseous state under experimental conditions.

2. Required equipment

Gas distribution equipment: vacuum pump, vacuum gauge, high and low pressure gauge, valve, cylinder fixture, chassis.

Weighing equipment: high-precision balance

2、 Infiltration method

1. Scope of use

The weighing method is suitable for the preparation of trace active wave gases. It is a dynamic gas distribution method.

2. Required equipment

Gas distribution equipment: permeation pipe, pressure stabilizing valve, flow stabilizing system, Liu Lainian flowmeter, temperature recording instrument, valve, pipeline, mixing tank.

3、 Partial pressure method

1. Scope of use

Partial pressure method is applicable to the preparation of standard mixed gas with content of 1~60%, which is gas at normal temperature

2. Required equipment

Gas distribution equipment: cylinder manifold, pressure gauge, valve, vacuum pump, pipeline, cylinder fixture.

4、 Diffusion method

1. Scope of use

Partial pressure method is applicable to the preparation of organic gases that are liquids at room temperature

2. Required equipment

Gas distribution equipment: gas cylinders, valves, flow control valves, flow meters, liquid components, analytical instrument cylinders, fixtures.

5、 Static volume method

1. Scope of use

The static volume method is applicable to the preparation of a variety of small and small amount of standard gases in the laboratory, and the pressure is close to the atmospheric pressure.

2. Required equipment

Gas distribution equipment: gas cylinders, cylinder pressure reducing valves, fixed volume pipes, pressure gauges, vacuum pumps.

6、 Saturation method

1. Scope of use

Saturation method is applicable to gas and steam easy to condense.

2. Required equipment

Gas distribution equipment: gas cylinder, cylinder pressure reducing valve, condenser, saturator, thermostatic controller, pressure gauge, circulating fan.

7、 Flow ratio method

1. Scope of use

The flow ratio method is a dynamic gas distribution method. It is a standard gas obtained by strictly controlling the flow of a certain proportion of component gas and diluted gas and mixing them.

2. Required equipment

Gas cylinder, pressure reducing valve of gas cylinder, one-way valve, flow controller, pressure gauge, pipeline, chassis.

8、 Dilution method

1. Scope of use

The dilution method is one of the methods for preparing low content standard gases.

2. Required equipment

Gas cylinder, pressure reducing valve of gas cylinder, flow controller, pressure gauge and pipeline.

9、 Volume ratio method

1. Scope of use

Volume ratio method is a simple gas distribution method, which is calculated by volume according to the required gas content. Control the volume of component gas and diluted gas, and get the standard gas after mixing.

2. Required equipment

Syringe, fixed volume container.