Parr Instrument Series 5500 - Manual (Page 7)

Compact Mini Bench Top Reactors
w w w . p a r r i n s t . c o m 7
Pressure and Temperature Limits
Working pressures up to 3000 psig (200 bar)
maximum are permissible in these Mini Reactors
when constructed of Type 316 Stainless Steel and
equipped with a magnetic stirrer drive. Pressure
limits for reactors made of materials other than Type
316 Stainless Steel can be obtained from customer
service. No attempt should be made to increase
these limits by making alterations or by substituting
components which are not recommended by Parr
Instrument Company. It must also be understood
that lower pressure and temperature limits may
be required for modified reactors and for vessels
made of special alloys. Limits for such vessels will
be determined by the physical characteristics of the
material of construction and will be prescribed on
an individual basis.
Working temperatures up to 350 ºC are permissible
in Mini Reactors equipped with a standard, flat
gasket, No. 457HC2, made of PTFE fluoropolymer
resin. A PTFE gasket is the recommended choice
for most applications since the PTFE resin is inert
to most chemicals and it will provide good seals
under repeated opening and closing if the gasket
temperature does not exceed 350 ºC. The service
life of a PTFE gasket will, however, be reduced
considerably if used at temperatures above 300 ºC.
For better service in the 300 ºC to 350 ºC operating
range Parr recommends a flexible graphite gasket,
No. 457HC3KL.
The maximum working pressure and temperature
for any vessel is governed by the design of the
vessel and the strength of the material from which
it is constructed. There is also a close relationship
between working pressure and temperature since
the strength of any material will normally fall off as
the temperature is increased.
Temperature and pressure limits are also affected
by the physical properties and temperature limits
of the gaskets and seals used in the vessel, and by
any valves, gages or other fittings attached to the
vessel. Obviously, the safe operating pressure of
any system can be no higher than that of its lowest
rated component.
Working temperatures up to 225 ºC are permissible
in mini reactors equipped with fluoroelastomer
(FKM) O-ring seals. The higher the operating tem-
perature above 200 ºC, the shorter the life of the
O-ring will be. Perfluoroelastomer (FFKM) O-ring
seals have a broad chemical resistance and can be
used to temperatures up to 300 ºC. Unfortunately
they are very expensive and will generally be re-
served for unique applications. Ethylene-propylene
(EP)
O-rings can be used to 170 ºC and are recommend-
ed for applications such as ethers, ammonia and
amines which will rapidly destroy fluoroelastomer
O-rings.
Pressure and Temperature Limits
The working pressure and temperature in these 100 mL thru 600 mL reactors must not exceed the following maximum limits:
Vessel Material Maximum Pressure Maximum Temperature
T316SS 3000 psig 350 ºC PTFE Flat Gasket
T316SS 3000 psig 225 ºC FKM O-Ring
T316SS 3000 psig 300 ºC FFKM O-Ring