Double Jacketed Gaskets

GASKETS

Metal-plastic gaskets, also called double-jacketed gaskets, consist of a metal jacket and a soft material filler.

The sealing filler provides excellent resilience, while the metal coating (or jacket) protects against pressure, temperature fluctuations and corrosion.

They are useful in a variety of applications. Especially in heat exchanger equipment.

• Coating (jacket or envelope):
  • Copper
  • Stainless Steel
  • Carbon Steel
  • Brass
  • Monel
  • Others: Nickel, Aluminium, Titanium, Hastelloy, Incoloy, Silver, etc.
• Filler:
  • PTFE
  • Asbestos-free fibre

Profile	Section	Material	KO	K1	RZ *
			[N/mm]	[mm]	(µm)
FW3 F3 F4		Al	50 bD	1,4 bD	25 a 50
F6		Cu	60 bD	1,6 bD	12,5 a 25
F8		Ni	70 bD	1,8 bD	6,3 a 12,5
F10		CrNi – Steel	100 bD	2,0bD	2,5 a 6,3
F12
F17		Steel	60 bD	1,6 bD	12,5 a 25

* Recommended surface roughness of flange sealing surfaces

Metal-plastic seals are seals with a metal-to-metal contact surface. This results in relatively high minimum sealing forces. The table of minimum min (joint closure) and maximum max (breaking limit) stresses for metal-plastic joints is given below:

When installing the metal-plastic seal in the device, the arrangement of the housing and the cover in the tongue and groove socket must be taken into account. Accordingly, the shell side should be installed towards the male and the cover side towards the socket (female); otherwise the seal may be irreversibly damaged by premature collapse of the cover.

Sometimes it is desired that the metal-plastic gasket be without ribs (one-piece gasket); in this particular case the minimum radius of connection of the rib to the ring is r = 10 mm.

It has been widely demonstrated that manufacturing with welded ribs is more economical and technically better (better sealing), since in this case there is a double sealing line as opposed to the construction of the one-piece joint, which only has one sealing line.

Double Jacketed Gaskets: A Versatile Solution for Industry

Metal-plastic gaskets are essential components in many industrial applications, especially in systems requiring reliable seals to ensure tightness under variable conditions. In this article, we’ll explore what metal-plastic gaskets are, their features, benefits, and the key applications that make them stand out.

What Are Double Jacketed Gaskets?

Metal-plastic gaskets combine metallic and non-metallic materials to deliver effective sealing across a wide range of applications. This hybrid design allows these gaskets to adapt to various operating conditions, providing both structural strength and flexibility/adaptability.

Typical Structure of a Double Jacketed Gasket:

• Metal Component: Acts as the structural backbone, providing mechanical strength. Common materials include carbon steel, stainless steel, or special alloys.
• Plastic Component: Usually made from materials such as graphite, PTFE (Teflon), or KEMMICA® (mica), depending on the application environment. Its primary role is to ensure a hermetic seal by conforming to surface irregularities.

Characteristics of Double Jacketed Gaskets

Metal-plastic gaskets are designed to offer a balance between mechanical strength and sealing flexibility. Key features include:

• Ability to Adapt to Irregular Surfaces: The soft component ensures reliable sealing even with imperfect flange surfaces.
• Chemical Resistance: Depending on the filler material used, they can withstand a wide range of aggressive chemicals.
• Wide Temperature Range: These gaskets are suitable for systems operating at moderate to high temperatures.
• Compatibility with Moderate Pressure Systems: Their design is ideal for applications with medium pressures, although they can handle higher pressures with specific configurations.

Advantages of Double Jacketed Gaskets

• Sealing Efficiency: They provide effective sealing for systems handling fluids or gases.
• Versatility: Adaptable to various industries due to their ability to operate under diverse conditions.
• Durability: The combination of materials ensures a prolonged service life, even in demanding environments.
• Ease of Installation: These gaskets are typically lighter and more flexible than alternatives, making them easier to handle and install.

Common Applications

Metal-plastic gaskets are widely used in sectors such as:

• Chemical Industry: In pipelines and tanks handling corrosive chemicals.
• Food Industry: In equipment requiring non-contaminating seals that resist moderate temperatures.
• Automotive Sector: In cooling systems, engines, and transmissions.
• Pharmaceutical Industry: In equipment requiring high chemical resistance and hygienic compatibility.
• Water Treatment: In pipelines and valves exposed to various chemical conditions.

Selecting and Maintaining Double Jacketed Gaskets

How to Select the Right Gasket:

• Evaluate the operating conditions, including temperature, pressure, and type of fluid.
• Ensure the filler material is compatible with the chemicals present in the system.
• Consider the equipment’s design and specifications.

Maintenance and Care:

• Regularly inspect gaskets for wear, damage, or deformation.
• Clean contact surfaces to avoid contaminants that could compromise the seal.
• Replace damaged gaskets to prevent leaks and operational issues.

Conclusion

Double Jacketed gaskets offer a reliable and versatile solution for a wide range of industrial applications. Their hybrid design delivers the best of both worlds: the strength of metal and the adaptability of plastic.

Do you have questions about choosing the ideal Double Jacketed gasket for your project? Feel free to ask or contact us for expert advice!

Kempchen-Comdiflex manufactures Double Jacketed gaskets in Spain, customized to any dimensions, designs, and compositions to meet your specific needs.

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