Page 136 - GarlockFluidSealing2010

Factors Affecting
Gasket Performance
A gasket is any deformable material which, when
clamped between essentially stationary faces, prevents
the passage of media across the gasketed connection.
Compressing the gasket material causes the mate-
rial to fow into the imperfections of the sealing areas
and effect a seal. This seal prevents the escape of the
contained media. In order to maintain this con-dition,
suffcient load must be applied to the connection to op-
pose the hydrostatic end force created by the internal
pressure of the system.
Gasket performance depends on a number of fac-
tors, including:
1. Gasket Metal and Filler Material: The materials
must withstand the effects of:
a. Temperature: Temperature can adversely af-
fect mechanical and chemical properties of the
gasket, as well as physical characteristics such
as oxidation and resilience.
b. Pressure: The media or internal piping pres-
sure can blow out the gasket across the fange
face.
c. Media: The gasket materials must be resistant
to corrosive attack from the media.
Forces Acting on a Gasket
2. Joint Design: The force holding the two fanges to-
gether must be suffcient to prevent fange separa-
tion caused by hydrostatic end force, resulting from
the pressure in the entire system.
3. Proper Bolt Load: If the bolt load is insuffcient to
deform the gasket, or is so excessive that it crush-
es the gasket, a leak will occur.
4. Surface Finish: If the surface fnish is not suitable
for the gasket, a seal will not be effected.
D-18
WARNING:
Properties/applications shown throughout this brochure are typical. Your specifc applica-
tion should not be undertaken without independent study and evaluation for suitability.
For specifc application recommendations consult Garlock. Failure to select the proper
sealing products could result in property damage and/or serious personal injury.
Performance data published in this brochure has been developed from feld testing,
customer feld reports and/or in-house testing.
While the utmost care has been used in compiling this brochure, we assume no respon-
sibility for errors. Specifcations subject to change without notice. This edition cancels
all previous issues. Subject to change without notice.