The factors affecting the sealing performance of the c are as below:
A. sealing surface quality; b. sealing surface width; c. pressure difference; d. sealing surface material and its processing state; e. medium properties; f. surface hydrophilicity; g. the existence of sealing oil film ; h. the solid and structural characteristics of the closure.
1) Influence of sealing surface quality on valve sealing performance
When the  sealing surface pressure load is below 40 MPa, the quality of the sealing surface plays a decisive role in the sealing performance of the valve. This is because when the sealing surface pressure load is small and the surface roughness is low, the amount of leakage would rapidly increase. When the pressure load on the sealing surface is large, the surface roughness has a significant effect on the leakage amount.
2) Influence of sealing surface width on valve sealing performance

The width of the sealing surface determines the length of the capillary. When the width is increased, the movement of the fluid along the capillary is lengthened, thus increasing the resistance to motion. Increasing the width of the sealing surface reduces the erosion wear in the high pressure valve. When the width of the sealing surface is increased, the length of the leakage stroke is proportionally increased, so that the leakage amount can be reduced proportionally. However, the width of the sealing surface is increased, and under the same sealing force, the sealing specific pressure is reduced, which increases the possibility of leakage. Therefore, the sealing face width cannot be increased indefinitely.

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