Little Element Yet So Important: Spiral Wound Gaskets

Spiral Wound Gasket, abbreviated as SWG, is that little thing that makes a huge difference. 

These gaskets are made from a thin metal strip placed between non-metallic filler layers. Alternative spiral layers of thin metal sheet and filler material are used by SWG.

This sort of gasket is frequently utilized with flange surface finishes generated with a flange-facing machine. The oil, gas, and petrochemical sectors require gaskets that can withstand high pressures, intense temperatures, and chemical attacks.

Fluctuations in the foregoing, as well as a temperature differential across the flange face and bolt tension relaxation, necessitate a flexible and recoverable gasket. It is impossible to overstate the importance of the gasket’s ability to rebound from changing conditions.

Construction of a Gasket

A spirally wound v-shaped stainless steel strip and a non-metallic filler material, such as graphite or PTFE, make up the semi-metallic spiral wound gasket. A complete outer ring is also included on the gasket, which is used for compression centring and control. This reduces the chance of material creeps due to overtightening.

Spiral wound gaskets with an additional inner ring are available for the harshest situations. This prevents contamination or attack of the windings (especially the filler) by the product passing through the pipeline joint.

Things to consider during the installation of spiral wound gaskets:

• The flange faces should be clean and free of indentations and scoring when fitting gaskets on a new flange or replacing an old one. Cross-face scoring is a key source of concern since it might result in joint leakage.
• When scoring is present, a portable machine tool like the Mirage Flange Facing Machine can be used to re-machine the flange surface. The flange faces should be parallel and concentric without the need for significant bolt pressures to pull them into place.
• It’s never a good idea to reuse a spiral wound gasket. Always start with a fresh one. Check that the gasket is not damaged and that it fulfils the required specifications before installing it.
• No lubricants or jointing chemicals should be utilized.

After installation, check the flange faces are parallel. This can be carried out with a flange gap measurement tool.

The spiral wound gasket is supplied with an outer ring consisting of Carbon steel, Stainless steel, or other materials such as Monel or Nickel for applications involving elevated face flanges. The outer ring works as a compression stop and provides the gasket with centring capability as well as winding blow-out resistance.

Many SW gaskets for sensitive applications contain an inner guide ring, which increases the gasket’s resistance to thermal shock and prevents the filler material from being sucked inside the pipe in vacuum service. On male-and-female flanges, such as those found in heat-exchanger, shell, channel, and cover-flange junctions, inner rings should be utilized with spiral wound gaskets.

Gaskets with flexitallic spiral wound gasket:

Flexibility and recovery are required to fight the impacts of pressure and temperature variations.

The Flexitallic spiral wound gasket is a precision-engineered solution for flanged joints, heat exchangers, boiler handholes, manholes, and other high-temperature, high-pressure applications, with resistance to practically every corrosive and poisonous element.

 

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