Parr Instrument Series 4580 - Manual (Page 14)

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HOW TO USE THE VESSEL
Fixed Head Vessels
To Open the Vessel
Lower the heater and push it aside
before attempting to remove the split ring
and cylinder.
Raise the cylinder support holder to the
bottom of cylinder. Open the gas release
valve to discharge any internal pressure.
Next remove the split rings.
Loosen bolts in a criss-cross pattern,
reversing the tightening procedure, gradually
decreasing the torque on each bolt. The
split ring halves can now be removed. In the
fixed head arrangement the head with
attached connection lines will remain in
place. The cylinder can be lowered.
Before Closing the Vessel
Examine the head seal carefully to be
sure that it is in good condition. The seal
should not have any nicks, be hardened, or
deformed. Examine the mating surfaces on
the cylinder and head to be sure they are
clean and free from burrs.
To Close the Vessel
Put the two split ring halves around the
head and cylinder flanges. Tighten the bolts
finger tight and then follow the torque
procedure listed below.
Removable Head Vessels
First, open the gas release valve to
discharge any internal pressure. Loosen
bolts in a criss-cross pattern, reversing the
tightening procedure, gradually decreasing
the torque on each bolt.
The moveable head style can be lifted
out of the cylinder. Care must be taken not
to damage any of the internal fittings.
To Close the Vessel
Slide the two split ring halves around the
cylinder and head flanges.
Sealing Vessels with Flexible Graphite
Gaskets
A torque wrench should be used to
tighten the compression bolts on vessels
equipped with a flexible graphite gasket.
Since both 6-point and 12 point bolts are
used on various Parr high pressure vessels,
the user must be sure that the torque
wrench is fitted with an adapter which
matches the bolts on which it will be used.
Additional information about flexible
graphite gaskets for use to 500 °C can be
found in Manual 285M.
To ensure uniform loading, clamp the
cylinder in a vise service fixture or attach an
anti-rotation clamp; inspect the gasket and
set the head in place. Slide the split ring
sections into position, turn each of the
compression bolts finger-tight, and then
apply the sealing force with a torque wrench
in the following manner:
Pick a starting bolt and tighten it to
approximately 15 ft-lbs. Then by-pass the
adjacent bolts and move around the closure
to a bolt approximately 180 degrees from
the start. Torque the second bolt and
continue in the same pattern until all are
snug at 20 ft-lbs. Then repeat the
procedure, increasing the torque to the
required limit shown in the table below.
Note: The following steps are common to
both head configurations.
Gas Connections
Gas connections are dependent on
applications. For most applications the
A506HC hose furnished with the system is
sufficient. Attach the Type “A” coned
pressure fitting into the adapter attached to
the gas inlet valve and tighten the
Recommended Bolt Torque
For Flexible Graphite gaskets:
3000 PSI 35 ft-lbs
For PTFE gaskets:
2100 PSI 25 ft-lbs