Why you should stop using gate valves in the oxygen pipeline?

In recent years, with the increase use of oxygen, some users have used oxygen pipes to deliver oxygen. Due to the long pipeline and wide distribution, and the sudden opening or quick closing of the valve, accidents that cause the combustion and explosion of oxygen pipelines and valves often occur. Therefore, making a comprehensive analysis of the hidden dangers existing in oxygen pipelines and cold doors, and taking corresponding measures is crucial.

1. Analysis of several common causes of combustion and explosion of oxygen pipelines and valves.

1) The friction between the rust, dust, welding slag in the pipeline and the inner wall of the pipeline or the valve port produce high temperature, causing combustion.

This situation is related to the type, particle size, and air velocity of the impurities. Iron powder is liable to combust with oxygen, and the smaller the particle size, the lower the ignition poin, the faster the gas velocity, the more prone to cause combustion.

2) There are low-flammable substances such as grease and rubber in pipes or valves, which ignite under local high temperature.

3) The high temperature caused by adiabatic compression makes combustibles burn.

For example, the pressure is 15MPa in front of the valve, the temperature is 20 ℃, and the normal pressure is 0.1MPa at the back of the valve. If the valve is opened quickly, the oxygen temperature can reach 553 ℃ according to the adiabatic compression formula, which has reached or exceeded the ignition point of some substances.

4) The reduction of the ignition point of combustibles in high-pressure pure oxygen is the cause of the combustion of oxygen pipeline valves

Oxygen pipelines and valves are very dangerous in high-pressure pure oxygen.

2. Precautionary Measures

1) The design should comply with relevant regulations and standards.

The design should comply with the “Several Provisions for Oxygen Pipe Networks of Iron and Steel Enterprises” issued by the Ministry of Metallurgy in 1981, as well as the “Technical Regulations for the Safety of Oxygen and Related Gases” (GB16912-1997), “Code for Design of Oxygen Stations” (GB50030-91) and other regulatory standards Requirements.

2) Installation Precautions

A. All parts in contact with oxygen should be strictly degreased, and then cleaned with dry air or nitrogen without oil after degreasing.

B. Welding should be argon arc or arc welding.

3) Precautions for Operation

A. Open and close the oxygen valve slowly. The operator should stand In the side of the valve and open it once.

B. It is strictly forbidden to blow the pipeline with oxygen.

C. Implement the operation ticket system, and make more detailed explanations and regulations on the purpose, method and conditions of the operation in advance.

D. Manual oxygen valves with a diameter greater than 70mm are allowed to operate only when the pressure difference between the front and rear of the valve is reduced to within 0.3MPa.

4) Maintenance Precautions

A. The oxygen pipeline should be inspected and maintained frequently, and derusted and painted once every 3 to 5 years.

B. The safety valves and pressure gauges on the pipeline should be checked regularly, once a year.

C. Improve the grounding device.

D. The selection of valves, flanges, gaskets, pipes and fittings shall comply with the relevant provisions of the "Safety Technical Regulations for Oxygen and Related Gases" (GB16912-1997).

E. Establish technical files, train maintenance personnel.

5) Other Security Measures

A. Increase operation personnel attention to safety.

B. Increase the vigilance of management personnel.

C. Improve the level of science and technology.

D. Continuously improve the oxygen delivery plan.