The internal leakage of stainless steel valves is mainly from two aspects:
  1. The internal leakage of stainless steel valves is usually caused by the failure of the valve seal.
  2. Regardless of the defect of the valve body, the leakage of the valve is mostly caused by the damage of the middle flange or the stem stuffing box.

The first type: the isolation of the medium in the pipe is achieved by the sealing of the valve core and the valve seat surface due to the increased tolerance due to the adhesion and wear caused by the flatness of the two sealing surfaces; the erosion of hard particles under load; the bubble point state Vapor formation due to changes in liquid pressure, cavitation and damage to the protective film of corrosion-resistant materials, and corrosion of exposed metal in a corrosive environment may cause the valve core and valve seat seal to fail and cause internal leakage of the valve.

The second type: the sealing of the middle flange mainly depends on tightening the evenly distributed bolts. After determining the temperature and pressure level of the valve, the selection of bolts and gasket materials becomes the key to the sealing of the middle flange.
The leakage at the valve stem is realized by the stuffing box. The use conditions of the valve, stem material, packing performance and size, and packing pre-tightening force all affect the sealing of the stuffing box. The erosion and abrasion of foreign matter, loss of elasticity and loosening of the packing are the main reasons for the failure of the stuffing box seal.
Solution:
   1. Standardize design content.
   2. Change improper operation mode.
   3. Change the non-standard installation method.
  When designing and selecting, issue a valve specification including the design temperature and pressure, the nature and state of the medium, as well as the valve type, valve body and main internal materials, and the requirements of the connection. In this way, it can not only strengthen the awareness of design and selection, but also purchase the valve. Provide a scientific basis.

A large part of the cause of internal leakage may be caused by thought damage or wrong operation. In the production of advanced stainless steel valves, the production of advanced stainless steel valves is strictly regulated. The valve itself can completely avoid the occurrence of leakage. Choosing a high-quality valve is the key. Installation and maintenance are even more important. Only when a comprehensive protection of the valve is achieved, the internal leakage can be essentially solved.