Parr Instrument Series 4570 - Manual (Page 11)

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4570 HP/HT Pressure Reactors Parr Instrument Company
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
Instruction Sheet 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. 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 with a 1/8” dia.
Stainless steel sheath is furnished with the
reactor. Insert this thermocouple into the
thermowell and connect it to the
thermocouple socket on the rear panel of
the temperature controller using the A470E2
extension wire furnished with the reactor.
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, 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.