Frontier EGA/PY-3030D, Руководство по эксплуатации

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7-4
Ver.1.36
7.3 TYPICAL TROUBLESHOOTING PROCEDURE
The two most prevalent problems encountered when using the pyrolyzer are gas leaks (at the needle
interface) and a clogged ITF needle. Here are some examples of the symptoms associated with
these two problems:
・
Background peaks in the MS spectrum have a high abundance of m/z 28 and 32.
・
Poor reproducibility of pyrograms.
・
Insufficient column head pressure (flow).
The total flow setting for the carrier gas may be too low. Set it at 50 mL/min or more.
・
In the constant flow mode, the carrier gas pressure plateaus while the column is being
temperature programmed.
The carrier gas supply pressure may be too low. Set it to the proper pressure by consulting your
GC manual.
Troubleshooting for gas leaks is described. If symptoms mentioned above are observed, follow the
procedure below to troubleshoot.
(1)
Checking gas leakage of pyrolyzer
Perform the leak test below.
(1)-1 Plug the outlet of the separation column or EGA tube using a septum.
(1)-2 Plug the outlets of the split and purge vents using cap nuts.
(1)-3 When the carrier gas is turned on, the column head pressure increases and should be the
same as the supply pressure. If not, there is a leakage. Use a He leak detector to locate the
problem.
The causes of gas leakage originating from the pyrolyzer are provided here along with the solutions:
・
O-ring (Fig. 7.1a) that seals the upper end of pyrolysis tube has become loose.

Further tighten
the three hexagonal screws or replace the O-ring (P-6W, P/N:PY1-2017)
・
The graphite Vespel ferrule or graphite ferrule at ITF union has become loose or degraded (Fig.
7.1b)

Further tighten (work gently to avoid breaking the tube) or replace the ferrule (P/N:
PY1-7911 graphite Vespel ferrule, PY1-7921 graphite)
・
The metal ferrule on the ITF needle (Fig. 7.1b) has become loose or degraded.

Tighten it
further or replace the ITF needle (the metal ferrule is fixed to the needle, needle set P/N:
PY1-1274).
・
Liquid sampler (Fig. 7.1c) has become loosen, the O-ring of the sampler base has degraded or
foreign objects present.

Tighten it further (normally finger-tightening is adequate). Clean the
O-ring and the mirror-finished part of the sampler using a cotton swab dampened with methanol,
or replace O-ring (P-12 P/N: PY1-7811)
The work is done with an ITF needle N whose end is very sharp. For
your safety, wear protective gears such as safety goggles.
CAUTION
!