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4560 Mini Bench Top Reactors
Parr Instrument Company
Revision 6-28-02
HOW TO USE THE VESSEL
(
Continued
)
Note: The following steps are common to
both head configurations
.
Gas Connections
For a gas connection to the vessel,
use the A495HC pressure hose furnished
with the reactor. Attach the hose to a
pressure regulator or flow control valve on a
commercial gas cylinder using PTFE tape or
other thread sealant on the 1/8" NPT male
nipple and on the 1/4" NPT bushing, if used.
Then screw the Type A coned pressure
fitting into the adapter attached to the gas
inlet valve and tighten the compression nut
firmly. Do not use any thread dope or tape
on the coned fitting. The A495HC pressure
hose is made of reinforced Nylon which can
be used for all non-corrosive gases at
pressures up to 2500 psig. For operations
involving corrosive gases, this hose should
be replaced with an A490HC hose (optional)
which has a PTFE lining and a braided
stainless steel outer covering. These hoses
have the same fittings as in the A455HC.
Pressurizing the Vessel
Check all valves carefully before
admitting gas into the system. The liquid
sampling valve must remain closed
throughout the charging procedure. The gas
release valve must also be closed unless
the vessel is to be purged, or unless there is
to be a continuous flow through the reactor
during a run. Always make certain that the
pressure in the gas tank is greater than the
pressure in the vessel; otherwise liquid will
be forced out of the vessel and into the gas
tank when the inlet valve is opened. If there
is any possibility that the tank pressure
might not be high enough to force gas into
the reactor, install a one way check valve
(optional) in the gas line to prevent any
reverse flow.
With the inlet valve open and the flow
control valve on the gas tank closed, open
the main valve on the gas tank only about
one-quarter turn; then use the flow control
valve or the valve on a pressure regulator to
control the flow of gas into the vessel. After
the desired pressure has been reached,
close the tank valves and the vessel inlet
valve and disconnect the hose at the vessel
end.
Do Not Overfill the Vessel
Always watch the pressure gage
closely when admitting gas so as not to
exceed the maximum working limit.
Remember that any subsequent increase in
temperature will raise the pressure. Also, be
sure that the amount of liquid placed in the
vessel is carefully controlled. As a general
rule, the liquid charge should not exceed
two-thirds of the capacity of the cylinder.
Too much liquid in the vessel can lead to
development of dangerous pressures if
sufficient space is not provided for
expansion when the liquid is heated. This
hazard is explained in greater detail in a
warning statement included in the Instruction
Manual No. 230M.
Releasing Pressure
Use the gas release valve to reduce
the pressure in the vessel if the reactor is
accidentally overcharged when filling. Use
this valve also to release any excess
pressure during a run and to exhaust the
vessel at the end of a run. If the discharge
gases are flammable or toxic, discharge to
an exhaust hood or to any other safe
release point.