Safety Practices and Hazards
18
Agilent 240/280 Series AA (including Zeeman)
Use only acetylene that is packed in acetone. Some gas suppliers offer acetylene
packed in material other than acetone. While these alternatives may overcome
some of the disadvantages of acetone, they may also introduce the more serious
problem of corrosion in the gas control module and must not be used with Agilent
atomic absorption spectrometers.
If the pressure in the acetylene cylinder is allowed to fall below 700 kPa (100 psig),
or the consumption is greater than 1/7 of the cylinder contents per hour, acetone
may be carried over from the cylinder and into the spectrometer. Acetone in the
spectrometer can damage seals, O-rings and hoses, degrade analytical
performance and precipitate flashbacks.
Minimize the amount of acetone that is carried over with the acetylene by:
Replacing cylinders when their contents pressure drops below 700 kPa (100
psi)
Ensuring that the rate of acetylene drawn off from each cylinder is not
excessive.
If high rates of consumption are observed, then connect two or more cylinders in
parallel to a manifold. This reduces the rate at which acetylene is drawn from each
cylinder.
To reduce the possibility of fire or explosion:
Test the supply ‘plumbing’ regularly for leaks with a brush and soapy water or
a proprietary leak-detecting solution (never use a naked flame when testing for
leaks)
‘Crack’ the cylinder before use by gently opening the valve to check for any
drops or spray of acetone. Any cylinder showing acetone should be returned
to the supplier for replacement.
Use ‘Instrument Grade’ acetylene that is at least 99.5% pure.
Turn off fuel gas at the cylinder when you have completed your flame analysis.
Refer also to your local regulations governing the use of acetylene.
Nitrous oxide
The decompression of high-pressure N
2
O gas at the regulator can cause
excessive cooling and eventual freezing of the regulator. To prevent regulator
malfunction and possible flashback, the gas should be heated with an in-line or
wrap-around heater.
Summary of Contents for 240 Series AA
Page 1: ...Agilent 240 280 Series AA including Zeeman User s Guide...
Page 63: ......
