scope:

2.2 SCOPE

The objectives of this research are as follows:

1. Develop general theories, which can be used for design, of gasket performance for R, RX, and BX gaskets. Fundamental to this is a prediction of leakage as a function of flange pre-load or flange face movement. Seating load prediction is also an important factor for designers and in that regard, previous API work on firesafety (7) will also be useful. The general theory should include the effects of size, pressure, pre-load, external loads, interference (for RX and BX gaskets), materials, and contained fluid (gas or liquid).

2. Perform finite element analyses of selected connections, including the gaskets to develop the theories.

3. Test selected sizes to evaluate the analytical work and the proposed design theories.

4. Provided limited guidance on tolerances and elevated temperature effects.

5. Provide some indication of the effects of cyclic service and fretting on gasket performance, at least on a limited basis.

The philosophy of this research project was to use the finite element method and full-scale testing to help confirm and validate general theories of behavior. The general theory of behavior which was evaluated was that leakage is likely to occur when the contact pressure between the seat and the seal is less than the applied internal pressure that is being sealed. This has been a simple concept of metal seals for some time (5).