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Installation and Maintenance Tips For All Gaskets
 All
too often we hear "the gasket leaks." This is not
strictly true. It is the joint that leaks and the
gasket is one component of several that make up the
joint. Unfortunately, the gasket is expected to make
up for any and all deficiencies in design, improper
installation procedures, and to compensate for all
flange movement due to thermal changes, pressure
changes, vibrations,etc. In many cases the gasket
will do these things but only when careful attention
is given to all the aspects of gasket selection,
design and installation. Experience in investigating
leaky joints over the years has indicated the most
common cause of leaky joints improper installation
procedures being followed.
Gasket
Installation Procedures (And Bolt Torquing)
1.
1.Inspect
the gasket seating surfaces. Look for tool marks,
cracks, scratches or pitting by corrosion and make
sure that the gasket seating surface is proper for
the type of gasket being used. Radial tool marks on
a gasket seating surface are virtually impossible to
seal regardless of the type gasket being used,
therefore every attempt must be made to minimize
these. If remachining of flanges is not possible,
investigate the use of patching cements such as
Devcon which can be fairly effective in repairing
the gasket seating surfaces.
2.
2.Inspect the gasket. Make sure the material is as specified,
look for any possible defects or damage in the
gasket.
3.
3.Inspect
and clean each stud or bolt, each nut, each washer,
and the facing on the flanges against which the nuts
will rotate. Look for severe galling, pitting, etc.
If any of the above mentioned items are damaged
beyond repair, replace that item.
4.
4.Lubricate
all thread contact areas and nut facings. The
importance of proper lubrication cannot be
overstressed. No joint should be made up without the
proper lubricant being applied to the threaded
surfaces and to the nut facings. When flanges will
be subjected to high temperatures, the use of an
anti-seize compound should be considered to
facilitate subsequent disassembly. There are
available on the market today a vast variety of
suitable lubricants that can be selected to provide
the necessary low coefficient of friction for
installation and adequate anti-seize properties for
high temperature application. The better the
lubricant, the more consistent will be the actual
achieved bolt stress at installation.
5.
5.With
raised face and flat face installation, loosely
install the stud bolts on the lower half of the
flange. Insert the gasket between the flange facing
to allow the bolts to center the gasket on the
assembly. Install the balance of the bolts and nuts
and bring all to a hand-tight or snug condition. (if
the gasket is being installed in a recess or a
groove, center the gasket midway into the recess or
the groove. If the joint is vertical it may be
necessary to use some cup grease or a few dabs of
gasket cement or some other adhesive compatible with
the process fluids, to keep the gasket in position
until the flanges are tightened.)
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