User`s guide

Routine Maintenance
287
1. Slide a single disk into the mouth at the base of the
barrel section of the tool until it drops into the tapered
hole.
NOTE: You must make certain that only a single gauze disk is
inserted. Attempting to insert two disks stuck together will
usually damage the plastic plunger. When viewed against a
bright surface, two or more disks together will appear
much darker than a single disk.
2. Press the plunger down slowly until the gauze reaches
the required position, i.e., until the adjustable stop
prevents further movement.
3. The adjustable stop may also be set to cause the first
gauze disk to be pushed against the tube groove when
repacking the tube.
For this application the stop is set so that pressure on the plunger
causes the tube to push the ball just down into the base. If the gauze
disk travels too far into the tube, it will become distorted and spring
past the groove.
After considerable use, the plastic plunger tip may become worn or
broken. To replace it, unscrew it from the end of the plunger shaft
and install a new tip (P/N L407-1034).
Gauze disks with torn or ragged edges should not be used; they may
work loose after they are inserted.
When using the gauze-loading accessory to insert the second gauze
disk, do not exert too much pressure. If the second gauze disk is
forced down too hard, the adsorbent is compressed, resulting in a
large pressure drop across the tube. This will adversely affect
subsequent thermal desorption and pumped-air monitoring
procedures. Push the plunger of the gauze-loading accessory down
only until the ball-bearing spring under the tube flexes slightly.
Conditioning Packed Sample Tubes
When conditioning freshly packed tubes, it is advisable not to set the
instrument immediately to the maximum temperature limit of the
adsorbent. Instead, it is better to use a less stringent approach by
increasing the temperature gradually over three or more successive