The sealing reliability of the valve directly affects the performance of the valve. In order to achieve better performance of the valve, special requirements are required for the structure and materials of the valve. The valve is used for hazardous media containing highly toxic gas, ammonia, sodium, heavy water or radioactive substances. Double packing sealing structure is adopted. The packing adopts high-quality flexible graphite braided packing, and the gasket adopts high-strength flexible graphite plate to ensure the reliability of sealing. The valve is used in high temperature, strong acid, strong alkali and other strong corrosion conditions. In addition to proper selection of the material of the internal parts of the valve (such as the valve stem is 1Crl8Ni9Ti or 2Cr13), high-strength bolts and nuts should also be used. " The sealing surface of the valve seat shall be made of different surfacing materials according to the actual working conditions of the transmission medium. The double eccentric semi pneumatic ball valve adopts a metal hard sealing structure, which is suitable for conveying gas-liquid two-phase flow media containing solid particles. It has been used in petroleum, chemical, gas, metallurgy, steel, power and other industries, and is welcomed by users.

The vicious competition of hot water pipelines affects the development of metal compensators in the heating industry
At present, the types of contraction joint compensators widely used in the field of heat supply include metal bellows contraction joints, sleeve contraction joints and rotary contraction joints. Among them, the metal bellows contraction joints used in the main pipe network of heat supply have some advantages, such as sensitive and diverse compensation methods, easy pipeline layout, and no maintenance during operation, It has been widely used in heating pipe networks in large and medium-sized cities such as Beijing, Tianjin and Taiyuan,
However, due to the problems of non-standard design and manufacturing and vicious competition in the industry, leakage accidents of bellows contraction joints occurred successively in Halbing, Datong and other places, which had a negative impact on the society, thus arousing users' doubts about the safety and reliability of metal bellows compensators and other products, Affects the development of metal compensators in the whole heating industry. The heating shrink joint compensator industry is in good development
With the constant promotion of new urbanization, large and medium-sized cities will add a large number of heat supply networks every year. At the same time, in order to improve the air quality of large and medium-sized cities, the central heat sources supporting the cities will also be moved to the surrounding suburbs and counties and towns, and the construction of long interval heat supply pipeline will be greatly increased. The diameter of the heat supply network will become larger and larger, and the pressure will become higher and higher, The demand for the safe and reliable operation of the pipe network is getting higher and higher. Recently, the country has put forward a planning request for the establishment of a comprehensive pipe gallery under the city. Therefore, in the next few years, the central heating shrink joint compensator industry will meet a good development opportunity, and at the same time, the demand for the safety and reliability of the shrink joint that compensates for the thermal displacement of the pipeline will also become higher and higher