Parr Instrument Flexible Graphite Gaskets User Manual
285M
Flexible Graphite Gaskets
Sealing Instructions
The amount of torque required to seal a pressure
vessel is a function of the intended operating
pressure.
The closure bolts may be tightened using either
an open-end wrench for smaller vessels where
the bolt torque requirement is less or with a
torque wrench where additional loading is required for the higher operating pressures.
Some of the gasket numbers shown in the attached table are furnished with vessels that have
different maximum working pressures. We have
shown the maximum torque value to correlate
to the maximum working pressure of the vessel.
It is important to make sure that the bolts are periodically lubricated with a high-temp anti-seize
compound to insure that they move freely so
that the desired torque value is obtained in the
tightening procedure.
It is also important to insure that there is uniform
loading on all of the bolts. Make sure that the
head sits levelly on the cylinder. Install the split
ring and tighten all bolts finger tight.
Pick a starting position and tighten the bolt to 5
or 10 ft-lbs depending on the maximum amount
of torque to be applied. For those vessels with
a maximum torque requirement of 15 ft-lbs, a 5
ft-lb increment is appropriate. For vessels with a
maximum of 135 ft-lbs, 20 ft-lb increments may
be used.
Bolt tightening should continue in a criss-cross
pattern from the initial bolt with the second bolt
180 degrees from the first and continuing until
all bolts are tightened. Repeat this procedure
increasing the torque to the required level as
shown in the table below.
Note: It may be possible to extend
the life of the flexible graphite gasket
by coating both sealing surfaces of the
head and cylinder as well as the gasket itself with a silicone base lubricant.
Additionally, it helps to rough up the
cylinder lip with 120 grit sandpaper to
insure that the gasket remains in the
head recess and does not stick to the
cylinder.
Recommended Bolt-Torque for Flexible Graphite Gaskets
Parr Part No. Pressure (psi) Torque (ft-lb)
315HC4KL 190 0 35
429HC2KL
457HC3KL
655HC3KL 1900 35
1808HCKL 5000 40
1812HCKL 3000 35
1829HCKL 8500 15
1559HC2KL 190 0 135
2303HC2KL 5000 55
211 53rd Street • Moline, Illinois 61265 USA 1-309-762-7716 • 1-800-872-7720 • Fax: 1-309-762-9453
285M R04 Revison 11/05/13
3000
3000 to 5000
3000
5000 to 6000
P
arr Instrument Company
E-mail: parr@parrinst.com • http://www.parrinst.com
15-20
20-25
35
40
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