Parr Instrument Series 4530 - Manual (Page 9)

Floor Stand Reactors
w w w . p a r r i n s t . c o m 9
OTHER VESSEL HEAD FITTINGS
Safety Rupture Disc
There is a safety rupture disc attached to the head that
is intended to rupture and release the pressure be-
fore it reaches a dangerous level. A metal tag wired to
the safety head identifi es the burst pressure at room
temperature for that particular disc. A similar tag is
furnished with each replacement disc. This tag must
remain with the apparatus at all times so that both
present and future operators will be aware of the disc
rating. Users should read the discussion of rupture
discs given in the Instruction Sheet No. 231M for a
complete description of the characteristics of rupture
discs and the precautions to be observed when op-
erating pressure equipment protected by this type of
safety device.
A typical pre-bulged disc can be used to 90% of the
rating on the tag. For additional protection, the user
should install an adequate and safe venting system
for removing any toxic, fl ammable or volatile mate-
rial which would be released if the rupture disc should
burst. A connector for attaching 3/8” OD tubing to the
discharge port of the rupture disc is provided for this
purpose.
Type J Thermocouple
A Type J thermocouple in a 1/8” dia. stainless steel
sheath is furnished with the reactor. Insert this thermo-
couple into the head thermowell and connect it to the
thermocouple socket on the rear panel of the tempera-
ture controller using the A470E2 extension wire fur-
nished with the reactor.
Pressure Gage
The pressure gage furnished with this reactor has a
T316 Stainless Steel Bourdon tube. Gages are fur-
nished in a variety of ranges to meet individual needs.
Typically, the gage and the rupture disc are furnished
as matched ranges. For applications where a gage is
selected with a range under 1000 psi, a relief valve is
added and set to protect the gage. A 1000 psi rupture
disc is installed as the fail-safe vessel protection.
For highly corrosive applications where the vapor
phase might corrode the stainless Bourdon tube, Parr
offers isolator assemblies in a variety of materials.
These isolators with their internal piston isolate the
vapors from the gage.
The gage adapter includes a ¼” NPT side port with a
plug installed. This position may be used for a variety
of fi ttings such as a needle valve, pressure transducer
or relief valve.
Gage and Valve Adapters
The pressure gage and the combined gas inlet and
sampling valves are attached to the head with an
adapter which allows these fi ttings to be drawn up
tightly when facing in any direction. To attach these
fi ttings to the head, screw the gage or valves fi rmly
into the adapter, then run the 209HC4 bushing onto the
threaded stem as far as it will go. Screw this assembly
into the head until the nose of the adapter is seated;
then back it off until the valve or gage is facing in the
desired direction. Now hold the fi tting fi rmly in place
and close the joint by tightening the 209HC4 bushing.
This connection can be made and broken repeatedly
without destroying the sealing faces. A light coating of
thread lubricant, such as Parr No. 424HC2 High Temper-
ature Anti-Seize Lube, applied to the threads and to the
nose of the adapter will help to obtain a tight joint.
Note: Do not use PTFE tape on the straight thread
connections of the coned adapters and mating bush-
ings. PTFE tape should only be used on the (NPT)
threads such as the needle valves or gage connection.