Parr Instrument Series 4580 - Manual (Page 7)

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FIXED HEAD OR REMOVABLE HEAD DESIGN
Parr Series 4580 High Pressure/High Temperature Reactors are furnished with two structural
options in addition to the size, pressure range, stirrer motor, controller and similar options. These
are:
There is no difference in the pressure or
temperature limits or basic operating
instructions based upon the fixed head or
movable vessel options. There are
differences in the design of the stand
components which adapt the vessels to the
support system.
In the fixed head design, the head of the
vessel may remain fixed in the reactor support
stand. All attachments to the head, gas and
liquid feed and discharge lines, cooling water,
vapor take-off and condenser, thermocouple,
and any electrical leads can remain
permanently in place. The reactor is opened
by removing the cover clamp sections and
lowering the cylinder away from the head.
In the removable head vessel design, all
connections to the head are removed to allow
the vessel to be opened.
Flat Flexible Graphite Gasket
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 sixteen compression bolts
which must be tightened to develop the
loading on the gasket.
An alternate PTFE gasket may be used for
operating temperatures up to 350
C. Metal
gaskets can be furnished for special
applications. The metal gaskets are not
interchangeable with the flat gasket design,
but require special grooves machined into the
head and cylinder.
Parr recommends the flexible graphite
gaskets for most applications.
Fixed Head with Flat Gasket Moveable Head with Flat Gasket