PerkinElmer PINAACLE 900 Series, Customer Hardware And Service Manual

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60
Preparing Your Laboratory
Usually acetylene is dissolved in acetone, thus the tanks must be operated in the
upright position in order to prevent acetone from entering the tubing and hoses. At
low acetylene tank pressure the amount of acetone in the gas increases and may
produce an unstable flame. Therefore exchange the acetylene tank when the
cylinder pressure falls below 600 kPa (6 bar, 85 psig).
New tanks should be positioned vertically for at least 8 hours prior to use. The
practice of "cracking the valve" of an acetylene tank (that is, opening the valve
slightly fora very short period prior to attaching the regulator) is not recommended.
While such an action will clear the valve opening of dust or dirt particles and may
remove acetone from the cylinder valve, it is a potentially hazardous practice and
one which should never be attempted in the presence of an open flame, sparks or
other possible sources of ignition.
Both fuel and oxidant gas lines should be relieved of pressure at the end of the
working day or if the instrument is to remain unused for an extended period.
Cylinder valves should be closed to avoid the possibility of pressure regulators
failing and gas lines being subjected to the full cylinder pressure.
Nitrous Oxide:
For higher temperatures, nitrous oxide is used as an oxidant.
Warning: Explosion Danger
Acetylene line pressure from the tank to the instrument should never
exceed 103 kPa (1.03 bar, 15 psig). At the higher pressures, acetylene
can spontaneously decompose or explode.
PerkinElmer recommends that a maximum acetylene line pressure
of 80-95 kPa (12-14 psig) be used to provide a reasonable margin of
safety.
A flashback arrestor is required at the outlet of the pressure
regulator.
The nitrous oxide flame requires high flow rates of up to 30 L/min.
Simple pressure regulators may freeze and cause malfunction. The
two-step or heated pressure regulator is highly recommended.
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Warning
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Warning