GASKET DESIGN

When designing a gasket, a number of potential variables should be taken into consideration.

Application Variables

  • Temperature
    • High temperatures degrade materials
    • Consider both internal and external temperatures
  • Chemical Resistance
    • Interface with materials and binders can cause degradation




  • Flange Design
    • Flange surface finish is a factor in material function
    • Width of flange is proportional to amount of material that can be utilized
    • Flange composition
      • Material compostion affects performance
      • Dissimilar mating surfaces should be avoided
      • Bolt placement can cause material to blow out under internal pressure


      Flange Composition and Geometry
      Composition determines the strength or stiffness of the flange. The strength or stiffness is called the modulus.
      examples: aluminum
      steel
      cast iron
      plastic
      The higher the modulus the stiffer or more rigid the flanges. A higher modulus will generally allow the flange to more evenly distribute bolt load.


    • Hardware choice
      • Higher grade bolts are less susceptible to creep relaxation
      • Higher number of threads are less susceptible to creep relaxation
      • Length and type of bolts affect creep relaxation




    • Gasket Pressure Validation

      • EG Gasket has the capability to analyze their customers' sealing applications using Prescale/Pressurex Fuji Films. They provide a complete analysis of the total force, average pressure, and total square inches of contact over a sealing/flange surface area, plus, the pressure distribution can be displayed graphically. Let our staff help you determine the proper film pressure range for any given sealing application.

      If you can provide a drawing of the flange surface or current gasket, EG Gasket can pre-cut and prescale the film to match, a film that will be ready to assemble in the joint. We will even assist you in the process of assembly. Once we have applied pressure to the joint assembly, with the gasket in place, the film can be removed and read immediately, for sealing pressure feedback, or EG Gasket can use it to supply a complete analysis of the sealing application. All of this can be done by EG Gasket for a minimal investment from the customer.

      • Fugi paper tests for Flange load challenges

      • FEA Modeling
        • Finite element analysis (FEA) is the application of the finite element method to the analysis of static or dynamic physical objects and systems. A common use of FEA is for the determination of stresses and displacements in mechanical objects and systems. However, it is also routinely used in the analysis of many other types of problems, including those in heat transfer and fluid mechanics.

    • Outside environment
      • External conditions can degrade gasket
        • Paint
        • UV Exposure
        • Temperature
        • Chemical Exposure

TOOLING CONSIDERATIONS

  • Tolerances (Ref)
    • Steel rule dies-------+/- .005" to .015"
    • All steel tools-------+/- .005"
    • Compound tooling------+/- .0025"
  • Tooling cost reduction through gasket design
    • Identify critical dimensions
    • Radius corners where permissible
    • Ratio of flange width to material thickness should be at least 4 to 1
    • Distance between cutting edges of a minimum of 0.25"