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Recommendations for flat gaskets
Installation
Correct installation is the main requirement for the reliable functioning of a gasket. The bolts and the surfaces to be sealed must be selected according to the surface pressure (minimum required and maximum permissible) for the respective gasket.

Please note:
  • Only new, undamaged, and dry gaskets should be used. Observe the storage conditions (see below).
  • Clean the sealing surfaces carefully, without scratching them. Make sure that the sealing surfaces are dry.
  • Position the gasket centrally; do not apply any supplementary media (grease, releasing agent, or sealing compound) to gaskets or sealing surfaces.
  • Do not use corroded bolts, nuts or washers. The calculated surface pressures must coincide with the achieved pressures, therefore the bolts and nuts should be lubricated lightly.
  • Mount the second sealing surface parallel to the first surface, and tighten the bolts by hand.
  • In order to achieve an even distribution of surface pressure, the bolts must be torqued to the specified value "crosswise" and using at least 3 steps. Example:
Step 1:    20 % of the specified torque.
Step 2:    60 % of the specified torque.
Step 3:  100 % of the specified torque.
  • All bolts must reach the same specified torque.
  • Every gasket settles, especially after a longer period without loading. Therefore, the bolts should be retorqued to 100 % before commissioning.
  • Retorquing of fiber or PTFE-based gaskets that have already reached a higher operating temperature should only be done in the cold condition with great care and also in several steps, because there is a risk of destroying the gasket (especially with fiber gaskets that have hardened).

Storage conditions for fiber-based gaskets and gasket material sheets (FA to DIN 28091-2)
Maximum storage period is two or three years under the following conditions:
  • Temperature: below 20 °C
  • Relative humidity: 30...60 %
  • No direct sunlight
  • No artificial lighting with high UV content
  • No ozone
  • Stress-free storage
Any large deviation from the above will reduce the permissible storage period. In case of critical (e.g. toxic) gases, the storage period should not exceed one year. If necessary, the gaskets or gasket material sheets must be sealed in airtight and lightproof wrappings.

Fuji films for determining surface pressure
The Fuji "Prescale" film is ideally suited for the simple determination of the achieved surface pressure with flat gaskets, and its distribution over the sealing surface.

Depending on the sensitivity of the selected film, surface pressures between 0,2 N/mm2 and 130 N/mm2 are represented by different shades of red color. Fuji "Prescale" film can be ordered from: REINZ-Dichtungs-GmbH.

Give us a call under ++49 (0)731 7046-777.

Special applications
Frequently, there are applications in which simple, punched gaskets are not sufficient.

Especially with molded seals or gaskets for covers and housings, only a low surface pressure is possible, so that even very soft gasket materials are not compressed sufficiently. By means of screen printing, an elastomer bead is deposited on both sides of the gasket. Consequently, the bolt force is concentrated at these points, whereby the gasket is compressed sufficiently to provide a reliable seal. The same effect is achieved with the beaded, elastomer-coated metal gaskets MatriCS and RETALL.
 
In particular with media that are sensitive to contamination, or for increased sealability (especially with graphite), blow-out safety or chemical resistance, flange gaskets with an internal metal bead (preferably of stainless steel) are used. Such beaded gaskets require higher surface pressures during installation.
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