PTFE Gasket

Influence of PTFE Gasket Geometric Dimensions
       Influence of PTFE gasket thickness. Under the same compression load and the same medium pressure, the leakage rate decreases with the thickness of the PTFE gasket. This is because under the same axial load, a thicker PTFE gasket has a greater compression rebound. When the initial conditions have been met, a thicker PTFE gasket with greater elastic reserve can better compensate for the relative separation caused by medium pressure, and retain a larger residual compressive stress on the gasket surface, thereby reducing the leakage rate. However, it is not the case that the thicker the gasket, the better the sealing performance. This is because the conditions for establishing initial sealing differ with the thickness of the PTFE gasket. Due to the influence of friction on the surface, the PTFE gasket surface is in a triaxial compressive stress state, and the material's deformation resistance is greater; while the influence on the end of the PTFE gasket is smaller, and its deformation resistance is also smaller. Under the same preload, the middle part of the PTFE gasket is more prone to plastic deformation than the surface, making it more difficult to establish initial sealing. Therefore, when the thickness of the PTFE gasket reaches a certain value, the sealing performance.
Sealing of High-Pressure Equipment.
                            
High-pressure equipment sealing is widely used in the petrochemical industry. Its structure is relatively complex, and the manufacturing requirements are high. Compared with medium and low-pressure equipment and pipeline sealing, it has the following characteristics.
      To enable the PTFE gasket to achieve sufficient pre-compression sealing specific pressure and operational sealing specific pressure, ensuring sealing performance without causing it to collapse, metal PTFE gaskets are often used. The contact surface between the gasket and the sealing surface is very narrow, sometimes almost line contact.
      To reduce the size of sealing components, including the main bolts, the diameter of the sealing surface should be as small as possible, and the sealing surface should be as close to the inner wall as possible. Often, a cylinder end flange is used, paired with a double-headed stud structure, to minimize the size of the end flange. To achieve the desired sealing performance, self-tightening or semi-self-tightening sealing structures are more commonly used, i.e., making full use of the operational PTFE gasket to form the operational sealing specific pressure. Since the high-pressure space in high-pressure equipment is very valuable, the sealing structure should occupy as little high-pressure space as possible. Depending on the sealing force, high-pressure sealing can be divided into three types: forced sealing, semi-self-tightening sealing, and self-tightening sealing. Forced sealing relies on the tensile force of the bolts to ensure a certain contact pressure (or sealing specific pressure) between the top cover, sealing elements, and the cylinder end flange to achieve sealing. This type of sealing requires large bolt tension to ensure reliable sealing performance between the gasket, cover, and cylinder end under working conditions.