Parr Instrument Series 4580 - Manual (Page 16)

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HOW TO USE THE VESSEL
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Continued )
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.
Withdrawing Liquid Samples
Liquid samples may be withdrawn from
the sampling valve attached to the same
adapter as the gas inlet valve whenever the
vessel is pressurized. Always close the inlet
valve before withdrawing a liquid sample
and open the sampling valve cautiously
because liquid will be discharged with
considerable force. Be particularly careful if
the temperature of the sample is above its
boiling point at atmospheric pressure. If so,
it will “flash” and be lost as soon as it is
released from the vessel. This problem can
be avoided by connecting an optional 4351
Sample Collection Vessel to the sampling
valve to collect the liquid into an appropriate
receiver. The addition of a small amount of
gas can be used to clear the dip tube
between liquid samples so that the next
sample drawn through the tube will truly be
representative of the mixture.
Initial Operating Test
Read all operating instructions carefully
so as to be well acquainted with the correct
procedures for handling the vessel and for
operating the controller and other
accessories. An initial operating test should
be made, with only water, to check the
apparatus before starting the first
experimental runs. For this initial test, fill the
cylinder not more than half full of water and
run the temperature up to 150ºC while
checking the apparatus for leaks and
observing the performance of the
temperature controller.