Jacketed metal gaskets were once the industry norm; however, advances in fabrication led to the development of spiral wound gaskets.
Not replacing the jacketed gasket completely, but offering an alternative solution for applications requiring a robust sealing solution.
Both of these gaskets offer an effective seal for high-temperature, high-pressure, and chemical applications, and both are semi-metallic. However, they seal differently and exhibit subtle differences, making them suitable for various applications.
Throughout this post, we examine these differences further and explore the applications these gaskets are suitable for.
Spiral wound vs metal jacketed gaskets
Some of the key gasket comparisons between metal jacketed and spiral wound seals UK include:
Sealing performance
Spiral wound gaskets are incredibly stable under fluctuating pressure and temperature conditions, offering a good level of stress compensation. Spiral wound gaskets also have the capability to adjust to the changing working conditions they are exposed to in order to maintain a concrete seal.
In comparison, jacketed gaskets for all have a good overall sealing performance; unlike spiral wound gaskets, they lack elasticity, which can, over time, affect sealing performance. However, in pipelines where conditions include high pressure and high temperature, metal gaskets are a good solution as they can maintain a seal for a long time.
Adaptability
A spiral wound gasket is a suitable seal for various applications and environments. Offering temperature, pressure, and high levels of chemical resistance, spiral wound gaskets can withstand a great deal.
Metal jacketed gaskets, however, do not perform as well in ultra-low temperatures or where chemical corrosion is a feature. This is due to the material becoming brittle at low temperatures and the metal gasket corroding easily, especially if they don’t have any special protective coatings or alloy materials built into the gasket.
This is a significant difference, as spiral wound gaskets use soft fillers in order to add to their corrosion resistance.
Spiral vs jacketed makeup
When we examine the makeup of the gaskets individually, you will find that the spiral wound gasket can pull apart and be easily crushed. In comparison, metal jacketed gaskets are more robust, offering a high level of structural strength.
To help improve its strength, spiral wound gaskets can include an inner ring to prevent the windings from buckling.
Metal gaskets are therefore most suitable for static sealing as the compressed soft filler is encased in the metal jacket to support compression.
The makeup of a spiral wound gasket includes V-shaped metal strips and filler that provides the elasticity to the gasket, which supports better recovery.
Cost
Jacketed gaskets are cheaper to fabricate than spiral wound gaskets, making them cheaper to purchase.
Gasket compressions, spiral vs jacketed
Predominantly, industries such as the petrochemical sector prefer to use spiral wound gaskets for sealing; however, metal jacketed gaskets are better for applications that are exposed to external pressure.
The aim is to understand the pros and cons of each and better understand which gasket is most suitable for your application.
Spiral wound gaskets are typically used in:
- Pipe flanges
- Valves
- Pumps
- Pressure vessels
Metal jacketed gaskets can be found in:
- Heat exchangers
- Reactors
- Vessel manways
Jacketed vs spiral
Metal jacketed gaskets include a soft, compressible filler that is encased in a metal shell. This metal shell is typically made up of stainless steel, carbon steel, brass, aluminium, soft iron, and titanium.
Metal gaskets are also available in flat cross-sections or corrugated jackets, and the profiles can be single- or double-jacketed.
When these gaskets are compressed, stress is spread across the jacket with the filler conforming to any irregularities in the surface, providing a tight seal.
Jacketed gaskets work best with smooth and flat surfaces and can offer a long life in stable conditions. However, the drawbacks to these gaskets are that they have limited recovery, and bolt load can affect seal performance.
Spiral wound gaskets UK include a graphite or PTFE soft filler built into the spiral element of the gasket. Spiral wound gaskets are available as basic windings, can include a centre ring (suitable for raised face flanges), and include inner and outer rings (to prevent inward buckling and improve blowout resistance).
Offering a high level of elastic recovery, SPG is tolerant of thermal and pressure cycling as well as bolt relaxation. This type of gasket also has excellent resilience and recovery rates and is most suitable in applications that experience fluctuating temperature and pressure.
However, the main drawback to a spiral wound gasket is that this seal can fall victim to overcompression, especially if the seating stress is uncontrolled.
We would recommend metal jacketed gaskets for non-circular and complex pattern applications, and spiral wound gaskets for standard circular flanges.
Spiral wound gasket suppliers UK
Your gasket selection should be based on environmental conditions, flange type and style, shape and size of intended application, and maintainability.
At Specialist Sealing Products, we stock and provide a range of seals and gaskets suitable for a significant range of applications across various sectors.
Speak to a member of our team today and see how we can help you.
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