Benefits of the Centring Ring

The spiral wound gasket outer centering ring provides the following benefits:

1. Optimum location between the bolts.
2. Protection of the spiral wound element.
3. Additional security against gasket blow-out.
4. Acts as compression limiter preventing overloading and over compression of the spiral wound element.
5. Prevents radial-flow of soft fillers, such as P.T.F.E. For these reasons it is preferable to use spiral wound gasket with outer centering rings. On the outer ring is marked with nominal size, pressure class, standard and materials.

Benefits of the Inner Ring

The spiral gasket inner ring provides the following benefits:

1. Prevents radial-flow of soft fillers, such as P.T.F.E.
2. Reduces turbulence-minimizing flow resistance and crevice corrosion.
3. Acts as a heat shield when the spiral wound gasket is subjected to high temperatures. Inner and outer rings are particularly recommended for use on spiral wound gaskets exceeding class 600lbs, but specifically recommended for high temperatures and pressures to optimize the operational reliability of the spiral wound sealing element.

Material Selection

Material selected for the inner ring and winding metal is usually the same as the flange metal, in order to prevent corrosion and differential expansion problems. The outer centering ring is generally manufactured from carbon steel with an anti- corrosion treatment; however, the ring may also be manufactured in the same metal as the flange to prevent corrosion problems.