网络优化资料：

In recent years, all-welded ball valves have been used on foreign natural gas trunk lines, that is, the middle valve flange and dozens of pairs of bolts and bolt caps of the ball valve. Both ends of them are not equipped with flanges, but are welded with short pipes of the same size as the pipeline . The advantage of this is that the weight of the entire ball valve can be reduced, the weight of the ball can be reduced to the maximum, and the leakage can be reduced. It is connected with the pipeline, eliminating the need for connecting flanges, which is conducive to the overall anti-corrosion of the pipeline.

However, the production process and manufacturing process of the fully welded ball valve are more complicated, so the cost of the first conductive solenoid valve is also relatively high. Therefore, it is recommended that all-welded ball valves be used in higher pressure and more important pipelines, such as annular pipelines or main pipelines. Now in addition to imported fully welded ball valves, domestic valve manufacturers have also begun to produce ball valves. For the convenience of users, the following reference opinions are provided here.

The shell of the fully welded ball valve should be made of high-strength and corrosion-resistant forged steel.

The hydrogen sulfide in the gas reacts with iron to form iron sulfide, so the anti-corrosion inside the water pipe solenoid valve housing is the key. Of course, the external anti-corrosion is also very important.

It is recommended that users choose a valve seat with dual piston effect.

A good sealing structure directly affects the performance of the ball valve, and it is very important to use a valve seat with a double piston effect. The working principle of the double plunger effect valve seat is that the sealing pair has two sets of valve seat seals. If the upstream valve seat is damaged and the medium enters the middle cavity, the downstream end sealing pair can still play a sealing role with the help of the pressure of the medium.

In the seal structure, if the sealing pair can be made into a soft and hard seal type, it is ideal, that is, PTFE adopts soft seal, and stainless steel metal elastic ring adopts hard seal. This combination of soft and hard seal not only improves the seal The tightness of the parts, and it has fire resistance. After the soft seal is burnt, the metal hard seal can still maintain the basic sealing state. At present, a composite sealing structure is also being researched at home and abroad to ensure that the ball valve has better performance and longer service life.