|
Gasket material
 Fills
the space between two objects, generally to prevent
leakage between the two objects while under
compression. Gasket material saves money by allowing
less precise mating surfaces on machine parts which
can use gasket material to fill irregularities.
Gaskets are commonly produced by cutting from sheet
gasket materials, such as gasket paper (beater
addition), Non-asbestos, Rubber, EPDM, Nitrile,
Buna, Neoprene, Flexible Graphite, Grafoil, Aflas,
Kalrez, Viton, Silicone, Metal, Mica, Felt or a
plastic polymer such as Teflon®
(PTFE), Peek, Urethane, or Ethylene Propylene (EP).
In the past, the gasket material selected for
specific applications may contain have contained
asbestos.
Today's
sealing products manufacturer's in the United States
no longer produce or offer any asbestos containing
products. Gasket materials containing asbestos have
been claimed to have caused Asbestosis. Of course it
would take the grinding of gasket material to
release the fibers and then the breathing in of
those fibers....possible but in the real world this
would be rare. Wetting or oiling a gasket before
grinding for removal greatly reduces any risk (not
grinding is even better). Asbestos gasket material
is still used in most of the rest of the world and
is a very effective low cost material.
It
is usually desirable that the gasket be made from a
material that is compressible such that it tightly
fills the space it is designed for, including any
slight irregularities. The most common misconception
when selecting a gasket materials thickness is to
choose a gasket material that is too thick. The
thicker the material the more likely the material
being contained can weep through the pores of the
gasket material itself. This is a greater issue with
some materials than others. A rule of thumb is to
have the material thick enough to compensate for any
surface face irregularities and to permit some
compression. The required compression for your
gasket material will depend many factors including:
1)Surface area
2)Pressure being sealed
3)Size of bolts (assuming bolts are
being used)
4)Number of bolts
5)Condition of the bolts
6)Lubrication on the bolts
All
must be considered when determining torque. Torque
data must be determined using all of the above and
should be provided by an engineer. In most cases
unless your gasket is a standard ANSI or API flange
using Ring or Full Face gaskets torque data will be
difficult to come by (due to staffing and the fear
of law suits). In most cases the old tighten it
tight enough to stop any leaks but not too tight as
to completely crush the gasket is generally
accepted.
>>Next
Page
| 
