Important Factors Affecting Gasket Selection
Gasket selection is not an easy task, especially in the selection of gasket sealing materials, many factors must be considered. The variables appearing at the flange connection seem to be endless. All these uncertain factors affect the sealing effect of the gasket. In the past, the parameters "TEMP" (temperature, application, medium, pressure) seemed sufficient. But today, the quality of the flange, the amount of bolt thread insertion, the amount of flange rotation, the amount of bolt tension, the filler of the medium and the surface treatment of the flange all affect the sealing effect of the gasket. Therefore, various parameters must be considered in order to make an appropriate choice.
(1) Temperature
In most selection processes, the temperature of the fluid is the primary consideration. This will quickly narrow the selection, especially from 200 ° F (95 ° C) to 1000 ° F (540 ° C). When the system operating temperature reaches the limit of the maximum continuous operating temperature of a particular
gasket material, a higher grade of material should be selected. This should also be the case at certain low temperatures.
(2) Application
The most important parameters in the application are the type of flange and the bolts used. The size, number and grade of bolts in the application determine the payload. The compacted effective area is calculated from the gasket contact size. The effective
gasket sealing pressure can be obtained from the bolt load and the gasket contact surface. Without this parameter, it will not be possible to make the best choice among many materials.
(3) Medium
There are thousands of fluids in the medium, and the corrosivity, oxidation, and permeability of various fluids are very different. Materials must be selected based on these characteristics when selecting. In addition, the cleaning of the system must be taken into account to prevent erosion of the
gasket by the cleaning solution.
(4) Pressure
Each type of
gasket has its highest ultimate pressure. The pressure-bearing performance of the gasket decreases with the thickness of the material. Selection must be based on the pressure of the fluid in the system. If pressure fluctuates frequently, you need to know the details to make a choice.
(5) PT value
The so-called PT value is the product of pressure (P) and temperature (T). The pressure resistance of each
gasket material is different at different temperatures and must be comprehensively considered. In general, the gasket manufacturer will give the maximum PT value for the material.
