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14.0 MAINTENANCE
14.1 FITTING A NEw O RING TO THE DIE
The die "O" ring is used to prevent polymer from leaking past the die during a test.
Therefore, the "O" ring diameter should be slightly larger than the die so that it protrudes out slightly
from the recess in the die.
When the "O" ring becomes worn or damaged, it should be replaced otherwise low IV measurements
will be produced.
There is no hard and fast rule as to the frequency that the "O" ring should be replaced but this may
need to be replaced daily if samples are tested on an hourly basis.
O-ring
Die
Shown: Expansion Tool
To remove the "O" ring make a vertical cut in the ring using a sharp pointed scalpel or Craft Knife.
WARNING: Always wear cut resistant gloves, such as ones made of Dyneema.
Lever out the old "O" ring with the knife.
Place the die on the bench with the "O" ring slot uppermost.
Position the Expansion Tool over the top of the die.
Place a new PTFE "O" ring over the tapered end of the expansion tool.
Slide the "O" Ring over the tool onto the die by hand.
Position the "O" ring into the recess on the die.
The "O" Ring must now be fitted into the die recess by inserting the die with the "O" ring into the wide
end of the contraction taper tool and gently pushing it with the cleaning tool until it emerges from the
narrower opening.
Stretched O-ring
O-ring reformed to
correct size
Shown: Contraction Tool
PET Plus User Manual
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