What are the factors in selection of seals and gaskets?
6 Factors to Consider when Buying Seals and Gaskets
- Environment. Consider the environment of the seals.
- Application. This is an obvious, but nevertheless important, factor.
- Regulations. Sometimes factors outside the scope of the job can affect your choices.
- Chemical compatibility.
- Flange design.
How do I choose a thick gasket?
Flanges requiring thicker gaskets create problems that a gasket manufacturer cannot control. Therefore the best solution is to use or design flanges with higher available compressive loads, keep the surface finish in good condition, and use 1.5 mm or even 1.0 mm thick gaskets whenever possible.
What is the first thing to consider when selecting seals?
LIQUID. Identifying the exact liquid being handled is the first step in the seal selection process. Seal material must be able to withstand the fluid being processed. All seal materials must be chemically compatible with the fluid, or there is an increased risk of seal failure.
How do I choose a gasket hardness?
As a general rule, a rubber gasket should be soft enough to fill and seal the gap between two surfaces, but at the same time needs to be hard enough to resist loading forces and not be extruded out of the joint. Hardness of a gasket elastomer is typically measured by the Shore A scale.
What is gasket seating condition?
Gasket seating condition. The operating condition is used to verify the flange design will be sufficient enough to resist the maximum allowable working pressure. Whereas, the gasket seating condition is used to verify the gasket will be “crushed” or seated in order to provide a sufficient joint.
What does m and y mean in gasket factors?
well basically m and y are the gasket factors which are used for flange designers only as specified in the ASME Boiler and Pressure Vessel Code Division 1, Section Vlll, Appendix2. The m = maintenance factor which provides the additional pre-load needed in the flange fasteners to maintain…
What is a gasket factor?
Factor ”m” – defined by ASME code as gasket factor or tightening factor. This is a multiplier applied to the value of the internal fluid pressure in order to obtain the necessary working gasket seating pressure.
What is the Y constant of gasket stress?
The gasket must conform to the flange surface and be sufficiently compressed to compensate for internal voids or spaces that could be detrimental to a seal. The gasket stress required to achieve this initial seal is considered the y constant.
Which gasket constants should be used in the code formulas?
However, these constants, y (seating stress) and m (gasket factor), must be used in the code formulas unless the designer can justify the use of other values for these constants. Values for constants of specific gaskets are included in the ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, Table 2-5.1.