spirometallic gaskets

SPIRAL WOUND

GASKETS

Spiral wound gaskets consist of a metal strip with a “V” profile wound in a spiral form and filled with soft material.

The soft material provides the spiral wound gasket with sealing properties and the metal strip provides the stiffness properties.

The combination of these two types of materials makes spiral wound gaskets ideal for sealing fluids at high temperatures (up to 1000°C) and under high pressure conditions (up to 250°C).

Spirometallic Gaskets

“Mechanical durability, high flexibility and exceptional recovery in heavy operation conditions”

  • With inner ring, outer centering ring or both.
  • TA LUFT Fugitive Emissions Prevention Certificate (environmentally friendly)
  • Standard sizes acc/to ASME, EN or to customers specifications.
  • SS304L, SS316L, SS321.
  • Successfully used in a wide range of applications: piping, heat exchangers or pressure vessels on steam, petrochemical, nuclear and marine plants.
  • Extraordinary ability to adapt with recovery and flexibility under frequent fluctuations of pressure and temperatures.

Materials

In general, the metal strip of the spirals is manufactured in the classic 18/8 type stainless steels (AISI-316L, AISI-304, AISI-321), special stainless steels (AISI-309 or similar) and other materials such as Monel-400, Titanium, etcetera.

The soft filling (material that specifically performs the sealing function) can be supplied in Graphite, PTFE, ceramic material or other asbestos-free materials.

Profiles

perfiles juntas espirometálicas
materiales colores juntas espirometalicas

The most common nominal thicknesses for spirals are 3.2 mm and 4.5 mm.
For diameters up to 1200 mm, 4.5 mm thickness is recommended; for diameters up to 1800 mm, 5.5 mm thickness and for sizes up to 4000 mm, 6.5 mm or 7 mm thickness is recommended.
for sizes up to 4000 mm it is advisable to use 6.5 mm or 7 mm thickness.

Profiles and values

Profile Section Material/ Coating KO K1 RZ *
[N/mm] [mm] (µm)
SpV1 Perfil SpV1

Steel
Cr-Steel
CrNi-Steel
Monel
Titanium

50 bD 1,3 bD

12,5 a

25

SpV2 Perfil SpV2 55 bD 1,4 bD
SpV2J Perfil SpV2J 55 bD 1,4 bD
SpZ1J Perfil SpZ1J

CrNi steel
Asbestos free
PTFE o
Graphite

40 bD

1,2 bD

25 a 50

SpZ2J Perfil SpZ2J

*Recommended surface finish for the surface of the flange

We also manufacture spiral wound gaskets for fittings and equipment. It is also possible to manufacture oval shapes (for manholes) and there is also the possibility to manufacture special spiral wound gaskets with metal-plastic ribs for heat exchangers.

Perfil SpV2J

Spiral wound seals with an inner retaining ring are also available (profiles SpV1J, SpV2J). The inner ring makes the seal safer by protecting the spiral from the possible turbulent action of the fluid and from pressure and/or temperature oscillations, additionally preventing the lateral sliding effect that could occur.

Perfil SpZ1J
Perfil SpZ2J

In SpZ (zone) profile spiral wound seals, the filling is usually made of graphite and the middle zone of PTFE or special compressible graphite. In this type of seals, lower closing deformation forces are required, as the surface pressure is mainly concentrated in the middle zone.

The minimum surface pressure is 30 N/mm2, instead of the 45-50 N/mm2 that would be required for a normal gasket. The combined filler (the zone) also protects the gasket better against high pressures or varying load conditions, and its configuration allows it to withstand higher stresses than a normal gasket.

With spiral wound seals, values of 10-8 mbar/ s-1 m-1 (measured with a Helium leak detector) can be achieved, considering a central PTFE zone of DN-150.

Perfil SpFS

Spiral wound gaskets profile SpFS in “fire-safe” version are equipped with PTFE-filled tapes on the inside and graphite-filled tapes on the outside. They are suitable for applications where the product must not come into contact with graphite and where the operating temperature is below 280°C.

For temperatures above 280°C with the requirement of “fire-safe“, SpV spiral wound gaskets with graphite tape on the outside or SpZ gaskets with graphite zone can be used.

Surface pressure

Profile

Material

Surface pressure (N/mm2)
T = 20ºC T = 300ºC
smin smáx smin smáx
SpV1
SpV2
1.4541/Graphite 50 150 60 120

SpV1J, SpV2J

SpZ1, SpZ2

1.4541/Graphite

1.4541/Graphite: PTFE

50

30

300

150

60

45

220

120

SpZ1J, SpZ2J 1.4541/Graphite: PTFE 30 300 45 220

SpV1 *, SpV1J *

SpZ1 *, SpZ1J *

1.4541/Graphite

1.4541/Graphite+ PTFE

70

70

View note

View note

70

70

View note

View note

Note: Spiral wound metals marked with (*) are assumed to be confined in a tongue and groove pocket; the seal is based on metal-to-metal contact, which is why the upper limit of the smáx is not limited by the gasket material but by the strength of the flange.

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