Parr Instrument Series 4550 - Manual (Page 6)

4550 Floor Stand Reactors
P a r r I n s t r u m e n t C o m p a n y 6
Fixed Head or Removable Head Design
Parr Series 4550 Series Reactors are furnished with two structural options in addition to the size, pressure
range, stirrer motor, controller and similar options. These are:
Fixed Head or Removable Head Vessel Design
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 vessel design, the entire vessel
must be removed from the support stand for charg-
ing, product recovery, and cleaning.
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 dif-
ferences in the design of the stand components which
adapt the vessels to the support system.
Fixed Head with O-ring
Flat PTFE 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 six cap screws which must be
tightened to develop the loading on the gasket.
The self sealing design features an O-ring retained in
a groove on the vessel head. This design is self seal-
ing and the split ring used with this sealing system
does not require nor have the cap screws used with
the flat gasket.
Maximum temperatures of a given system are de-
pendant upon the material of construction and type
of seal. Other accessories may limit operating tem-
perature. The flat PTFE gasket can be used to operat-
ing temperatures as high as 350 °C. The flat flexible
graphite gasket can be used to operating temperatures
as high as 500 °C. The maximum temperature of the
vessels equipped with O-ring seals depends upon
the material used for the O-ring. The most common
material is a fluoroelastomer (FKM) which has a 225 °C
maximum operating temperature limit.
Moveable Head with Flat Gasket