Parr Instrument Series 4580 - Manual (Page 13)

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OTHER VESSEL HEAD FITTINGS
Safety Rupture Disc
There is a safety rupture disc attached to
the head which is intended to rupture and
release the pressure before it reaches a
dangerous level. A metal tag wired to the
safety head identifies 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 Operating Instruction No.
231M for a complete description of the
characteristics of rupture discs and the
precautions to be observed when operating
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, flammable or volatile material which
would be released if the rupture disc should
burst.
Type J Thermocouple
A Type J thermocouple in a 1/8” dia.
stainless steel sheath is furnished with the
reactor. Insert this thermocouple into the
thermowell; connect the A470E_ Series
extension wire to both the thermocouple and
the receptacle on the back panel of the
controller. For a single thermocouple connect
it to the “Primary Temp Input” position. If a
High Temp Cut Off or External Temperature
Limit package is part of the system, a second
thermocouple may be inserted in the
thermowell (or optionally in the heater
sidewall). This extension wire is connected to
the “Temperature Input” position on the rear
panel of controller.
Pressure Gage
The pressure gage furnished with this
reactor has a T316 Stainless Steel Bourdon
tube. Gages are furnished in a variety of
ranges to met 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 fittings 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
fittings to be drawn up tightly when facing in
any direction. To attach these fittings to the
head, screw the gage or valves firmly into the
adapter, and 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 fitting firmly 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
Temperature 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 bushings. PTFE tape
should only be used on the (NPT) threads
such as the needle valves or gage connection.