Which Is the Most Popular Semi-Metallic Gasket?

Spiral Wound Gaskets are the most used semi-metallic Gaskets for high pressure joints. Depending on the flange type and application, a wide variety of configurations of the Spiral Wound Gasket can be used. They are designed to maintain a seal in flanged joints under severe fluctuations of temperature and pressure.

Spiral Wound Gaskets are suitable for a wide range of operating conditions and can be adapted to suite almost all applications. The gaskets can seal fluid pressures up to 250 bar and temperature range of -200 Degrees Celsius to an excess of 450 Degrees Celsius. Spiral Wound Gaskets are manufactured by winding an alternating combination of a metal strip and soft filler material. The gasket depends upon the mechanical characteristics of a formed metal spiral strip. Rather than the compressive virtues of more traditional gasket materials. This makes it particularly suitable for low or fluctuating bolt loads.

Graphite is usually used in the sealing strips or fillers although sometimes other materials such as PTFE may also be used. Stainless steel is always used in the windings and the completed gasket is fitted into a steel ring of specific thickness. When the gasket is fitted into a flange and the bolt load is applied, flange closure is governed by the outer steel ring of the gasket. To further improve the pressure rating of the spiral wound gasket, a steel ring may be added to the inside which also protects the windings, particularly the filler from contamination or attack by the product.

Gaskets are color coated to help expedite the selection and identity of the gaskets one needs. The color on the outside edge of the centering ring identifies both the winding and filler material. The metallic winding material is designated by a solid color. The filler materials on the other hand, are designated by color stripes at equal intervals of the outside edge of the centering ring.