Parr Instrument Series 4558 - Manual (Page 16)

4555 - 58 Series
5G & 10L Pressure Reactors
- 15 -
HOW TO USE THE VESSEL
The vessels used in Model 4555, 4556, 4557, 4558, 4667 and 4668 Reactors have two
types of closures: fixed head and removable head. They are designed so that the vessel
cylinder and heater can remain together while the head and split rings are attached or
removed.
Flat Gasket or Self Sealing O-ring Closure
The flat gasket is held in a recess in the vessel head and a machine pilot on the cylinder
closes the recess to completely contain the gasket. The split ring closure used with this
gasket has compression bolts which must be tightened to develop loading on the gasket.
The closure is designed so that the compression bolts in the split ring sections must make
contact within a lip on the compression ring which will bring the split sections into their
proper position. When opening these vessels, the compression bolts must be loosened
enough to clear the retaining lip on the compression ring before the split ring sections can
be removed.
The self sealing design features an O-ring retained in a groove on the vessel head. This
design is self sealing and the split ring used with this sealing system does not require nor
have the compression bolts as with the flat gasket.
To Open the Vessel
Open the gas release valve to discharge any internal pressure; then loosen the
compression bolts in the split ring sections (flat gasket design). The split ring sections can
now be removed, and the head with all attached fittings is free to be separated from the
cylinder.
For removable heads, Disconnect the drive by pulling down on the bottom 1743HC
Coupler Halve to disengage the 1746HC Spider from it and swing the lift tube assembly
positioning the lift plate/lift cables over the head and attach the three cables to the lift eyes
in the head until all internal appendages clear the cylinder lip. Rotate the head assembly
around and lower it into the rear service position of the right hand stand assembly. Handle
the head carefully so as not to damage the stirring shaft and other appendages when they
are outside of the cylinder. The cylinder may also be removed from the heater and lowered
into the front service position of the right hand stand assembly.
For fixed heads, slowly and carefully lower the cylinder using the joystick on the
pneumatic lift.
Before Closing the Vessel
Examine the head gasket carefully to be sure that it is in good condition. In flat gasket
designs, after considerable use, some of the PTFE gasket may extrude into a thin, ragged
edge around the inside diameters. This does not necessarily mean that the gasket must be
replaced, but the extruded portion should be removed with a sharp knife. Examine the
mating surfaces on the cylinder and head to be sure they are clean and free from burrs.