1. Basic concepts of laboratory centralized gas supply:

Laboratory centralized gas supply means that all cylinders are centrally stored in the cylinder room, and gas is delivered to each laboratory (i.e. instrument end) through the cylinder valve.

When gas cylinders are stored centrally, flammable gases and combustion-supporting gases must be stored separately; Must be ventilated

Flammable gases such as acetylene, methane, chlorine, etc

Combustion-supporting gases such as oxygen, air, etc

2. Operating principle

The laboratory gas supply has two stage decompression and multi-stage decompression

The two-stage pressure reducing valve means that the cylinder end adopts a one-stage pressure reducing valve and the end adopts a one-stage pressure reducing valve to achieve the purpose of two-stage decompression. The laboratory generally recommends the use of two-stage pressure reducing, which can ensure the purity of the gas and save the cost, and also achieve the effect of multi-stage pressure reducing (recommended).

Multi-stage decompression that is, the end of the gas cylinder with two stage pressure reducing valve or multi-stage pressure reducing valve and the end of the two stage pressure reducing valve or multi-stage pressure reducing valve to achieve the purpose of the multi-stage pressure reducing valve, the decompression effect is similar to the two stage pressure reducing effect. But the cost will be higher.

3. Introduction to valves

When choosing the pressure reducing valve, we must consider the type of gas, the allowable pressure range, the maximum amount of gas and the flow rate, the structure of the pipeline and the place of use.

A: Due to the different use of various gases, there will be some differences in the choice of materials such as: general inert gas valve body and valve core with chrome copper (stainless steel can also be selected), acetylene and corrosive gas recommended valve body and valve core with stainless steel materials.

B: Chromium plated copper valve body and stainless steel valve core are recommended for non-corrosive and inert gas materials with gas purity of 5.06.0. Gas purity is 6.0 corrosive, toxic gas material recommended to choose stainless steel valve body, stainless steel valve core; Because the density of oxygen is too thick, it is different from other inert gases. When choosing the pressure reducing valve, it should be different from other gases.

C: cylinder pressure reducing valve (disposable pressure reducing valve)

According to the frequency and volume of gas used by the user, the cylinder pressure reducing valve is divided into single cylinder type decompression and multi-cylinder type decompression, and multi-cylinder type decompression can be divided into semi-automatic decompression and automatic decompression, and the corresponding cost will be different. The cylinder pressure reducing valve is installed uniformly on the top of the cylinder (single cylinder) or on the wall (double or multiple cylinders).

D: Terminal pressure reducing valve according to the user's installation mode, control mode can have many choices, such as

That is, an instrument needs to use several gases, with several terminal pressure reducing valves, at present most laboratories have adopted this method (recommended), the pressure is stable, the flow is stable.

That is, a terminal pressure reducing valve is installed, and then distributed to each instrument through the joint. The cost will be lower, but the pressure and flow of the gas will be affected to a certain extent

The terminal pressure reducing valve can be installed on the wall or on the table according to the appearance and user needs.