Flowserve Dual Gas Barrier Seals - Manual (Page 3)


Dual Gas Barrier Seals - Installation and Mintenance Instructions for Machinery Components
1.3 Explosion Protection
The mechanical seal is regarded as a machine element. Machine elements do
not need to comply with Directive 94/9/EC (ATEX 95 product guide) as these
are regarded as an integral part of a larger piece of machinery (pump, agita-
tor). This has been confirmed by both the EC ATEX standing committee as well
as the European Sealing Association (ESA).Reference is made to following
web-sites:
EC ATEX standing committee: http://ec.europa.eu/enterprise/atex/rotating.htm
ESA position statement: http://www.europeansealing.com/statements.html
For applications which require information on expected surface temperatures
of the mechanical seal faces, Flowserve document “ATEX 17 information dec-
laration” is available upon request. This document allows users to determine
typical surface temperatures based upon seal design, operating conditions and
face materials and may be used by the users to comply with ATEX 1999/92/EC
(ATEX 17).
1.4 Functional requirements
The proper functioning of a mechanical seal is only achieved once the follow-
ing conditions have been met:
• The sealing surfaces are lapped within specification
• Perpendicularity and concentricity between the shaft and the seal chamber
face and bore respectively
• Freedom of movement of the spring loaded components in axial direction
• Axial and radial shaft movements within Flowserve or OEM tolerances
whichever is the tightest.
• The seal is run under the conditions for which it was selected.
• The equipment in which the seal(s) is (are) installed is operated within nor-
mal parameters (no cavitation, excess vibration etc.)
• Prevention of sedimentation on shaft or sleeve surfaces caused by for
instance crystallisation or polymerisation
• Permanent gas fluid film between the sealing surfaces
!
If these function conditions are not fulfilled, the consumption of product, for
example, is increased and parts of the product can escape into the atmo-
sphere. Other effects can include high component temperatures.
See the directive 94/9/EC, 1999/92/EC and EN 146-5.