3. The influence of pressure difference before and after valve on sealing performance
Theoretically, the pre- and post-valve pressure difference and leakage are proportional. However, the test proved that, under the same conditions, the increase in leakage is more than the increase in pressure difference.
4. The influence of sealing surface material and its treatment state on sealing performance
The sealing surface material and its treatment state have a great influence on the amount of leakage. Since the size of the remaining gap between the sealing surfaces depends on the microscopic unevenness of the sealing surface, if a sealing ring of a steel material is used to cause the same degree of sealing, a large specific pressure must be obtained, and the value must exceed that of brass. The specific pressure value of the sealing ring.
The surface treatment state associated with the seal, such as the deformation of the peak, the change in the size and the seal gap, and other phenomena occur on the metal surface. It is obvious that the performance of the surface layer is significantly different from the performance of the base material. The change caused by the processing can affect the surface layer thickness of 50 μm. The base metal is not exposed during grinding. The work surface layer tissue is different from the metal matrix structure.
Material properties have little effect on geometry and microgeometry. The difference in metal properties is usually less than the influence of other factors. This situation is even more pronounced when the sealing surface is operated under low pressure conditions. When the specific pressure is higher than 40 MPa, the influence of the surface roughness on the sealing property is reduced, and the influence of the material is increased.
5. Effect of medium properties on sealing performance
The effect of the liquid medium on the amount of leakage is essentially determined by viscosity. In the same sealing valve, in the case of the same conditions, the medium with a large viscosity is much smaller than the medium with a small viscosity. The difference between the gaseous medium and the liquid medium is more obvious, except for saturated steam, which is easy to ensure the sealing.