Corrugated and grooved gaskets are part of the semi-metallic category. This type of gasket is a mixture of metal and a sealing material that plays the role of an elastic element between the two sealing surfaces. Corrugated and grooved gaskets are used for the sealing of flange joints from heat exchangers, under-pressure recipients, valves, high pressure pumps in petrol-chemistry, oil refining, paper, energy and nuclear industries.
The most often used gasket is the grooved gasket (kammprofile), followed by the corrugated and jacketed gaskets.
Grooved Gaskets GG (kammprofile)
are manufactured from a metal core with concentric grooves on both sides, covered with sealing material on both sides.
The grooved gaskets can resist to pressures of up to 350 bar and temperatures of up to 800°C, depending on the sealing material type.
Their application is for difficult sealing environments where performance is critical or where sealing stresses are low.
Advantages of grooved gaskets:
- Depending on the metal core, the gaskets can be refurbished (the only type of gaskets that can be used again after having been refurbished)
- Very good sealing properties for a wide variety of seating stress levels
- Helps the compensating of high temperatures and pressure fluctuations
- Excellent when used for narrow flanges
- Easy to manoeuver
Main standards for grooved gaskets:
- ASME B16.20
- EN 1514-6
- EN 12560-6
Recommended thickness of the ring: 3 mm or 4 mm.
Recommended thickness of the sealing material: 2 x 0.5 mm or 2 x 1 mm.
- Metallic ring: SS 304; SS 316L; SS 321; SS 304L; Carbon steel
- Sealing material: flexible graphite; PTFE; Mica; Ceramics
Types of grooved gaskets:
|GG-CR0- is an independent sealing element. Usually used for Tongue and Groove or Male and Female flanges connection. Not recommended for Flat Face or Raised Face flanges types due to misalignment issues.|
|GG-CR1- Composed of the sealing element and a guide ring machined from one piece of metal. Used for Flat Face and Raised Face flanges, where the outer ring allows the axial alignment with the pipe bore.|
|GG-CR2- Composed of the profiled core with a loose guide ring that is connected onto the outside diameter of the core. The guide ring is manufactured from a thin 0.5 mm plate sheet and is attached to the sealing element. Used for Flat Face or Raised Face when the material of the metallic core is very expensive or hard to machine. It is used for resistance to radial shear and temperature differences between the flanges.|
Grooved gaskets are also available in convex profile. The parallel profile core is the standard design.
Corrugated gaskets CG CG
are manufactured from a core of profiled metal plate in order to ensure the rigidity and durability of the gasket.
The shape of the profile and the thickness of the gasket depend on the diameter and width of the gasket.
Graphite layers can totally cover the metallic profile or, by request, just the inside part so that the gasket could also have a centre ring.
Are strictly connected to the materials that are to be used in the manufacturing of spiral wound gaskets.
- Temperatures: -200°C… 550°C
- Pressure: max 160 bar
- pH: 0…14
Recommended thickness of the core: 0,5 mm.
Recommended thickness of the sealing material: 2 x 1 mm.
Advantages of corrugated gaskets:
- Very good sealing properties at low seating stress levels
- Excellent resistance to radial shear
- Resistance to thermal cycling
- Can be used for flanges with imperfections
- Metal material: SS 304; SS 316L; SS 321; SS 304L; Carbon steel
- Sealing material: Flexible material; PTFE; Mica; Ceramics
Types of corrugated gaskets
|GRAFEX CG – Manufactured from corrugated steel rings covered on both sides with soft sealing material (graphite of PTFE). It is a high performance gasket for standard flange or heat exchanger applications.|
|GRAFEX CG-CR1 – For type FF flanges and for optimized width of the sealing area|
|GRAFEX CG with inner eyelet – increased sealing capacity, blowout resistance.|
Metal jacketed gaskets JG
consists of a metal cover and soft sealing material as filler.
Frequently used with heat exchangers, although they are more and more often replaced with corrugated and grooved gaskets.
They require mechanically processed flanges, high bolt loads and a correct alignment in order to provide an efficient sealing.
- Temperature: -200°C… 800°C
- Pressure: max 160 bar
- pH: 0…14
Recommended thickness: 3 mm; 4 mm.
Advantages of jacketed gaskets:
- Adequate for narrow flanges
- Easy to handle and install
- Suitable for high temperatures
- Metal material: SS 304; SS 316L; SS 321; SS 304L; Carbon steel; Copper; Aluminium
- Sealing material: Flexible graphite; PTFE; Mica; Ceramics; Type AF materials