Parr Instrument 4700 - Manual (Page 6)

General Purpose Pressure Vessels
P a r r I n s t r u m e n t C o m p a n y 6
CLOSURES
Split Ring Closures
Most Parr pressure ves-
sels are equipped with
a unique split ring cover
clamp in which the head
of the vessel is clamped to
the cylinder by a hardened
steel ring which has been
split into two sections.
These sections slide into
place from the sides
without interfering with
any fittings attached to the
head.
The closing force is devel-
oped by simply tightening
a set of compression bolts
in the ring sections with a
hand wrench. As a further
convenience, larger Parr
vessels in one and two
gallon sizes, and certain
high temperature and
high pressure vessels, are
equipped with split ring
closures which do not
require an outer retaining
ring or drop band. This
allows the vessel to be
opened and closed by
simply sliding the split ring section into place from
the sides and tightening the compression bolts
while the cylinder remains in place in its heater or
other fixed support.
Split Ring Closure Operations
All vessels with split ring closures, except the larger
Series 4660, 4670 and 4680 sizes, must be removed
from the heater and set on a bench or table top
before attempting to remove the split rings and
head.
1. To Open the Vessel: open the gas release valve
to discharge any internal pressure; then loosen
the compression bolts in the split ring sections.
Loosen the cone pointed screw in the outer band
and lower the band to rest on the table. The ring
sections can now be removed, and the head with
all attached fittings is free to be lifted from the
cylinder.
4751 125 mL Vessel with
Split Ring Closure and
4316 Gage Block Assembly
2. 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 or be hard-
ened, discolored, or deformed. Examine the
mating surfaces on the cylinder and head to be
sure they are clean and free from burrs; then set
the head on the cylinder.
3. To Close the Vessel: put the two split ring halves
around the head and cylinder flanges, fasten the
latches or tighten the bolts as assembled before.
4. Routinely inspect the bolts on split ring clo-
sures for lubrication and cleanliness. These
screws should not be allowed to dry because
the threads will seize. Regularly apply Parr High
Temperature Anti-Seize Lubricant before this
happens.
Screw Cap Closures
On the smallest Parr vessels a
threaded sleeve and screw cap
are used to clamp the head to a
cylinder. This is a union type cou-
pling in which proper alignment
between the head and cylinder
is always assured since neither
of these parts rotates when the
screw cap is tightened. The flat
gasket is held in a recess in the
head. The seal is made as the
lip of the cylinder is compressed
against the gasket through tight-
ening the screw cap and sleeve.
All components must be kept
clean. The gasket must be re-
placed whenever it becomes worn
or damaged. Any nicks in gasket
recess area or to the sealing face
of the cylinder must be avoided.
Operating 4700 Screw Cap Vessels
To close the Series 4700 Screw Cap Vessels: raise
the sleeve against the top rim of the cylinder; set
the head on the cylinder and attach the screw cap.
Turn the screw cap down until it is finger tight; then
set the vessel in a Parr A22AC3 bench socket and
tighten the cap firmly with a 21AC4 box wrench.
4703 22 mL Screw
Cap Vessel