2.9 Replacing the Glass Cylinder and the PTFE Piston
Replacing the glass cylinder and the piston does not require any additional tools. In certain cases the piston
extractor has to be used.
•
Remove the interchangeable unit from the base unit.
•
Unscrew the hose between the glass cylinder and the valve from the glass cylinder.
•
Rotate the blue UV protection 5 to 6 times to the left to loosen it.
•
You can remove the UV protection and pull out of the glass cylinder together with the piston inside it.
•
Insert a new glass cylinder and piston (Fig. 21) into the interchangeable unit, and then slip on the blue
UV protection again.
•
Tighten the blue UV protection again by rotating it 5 to 6 times to the right.
•
The piston rod should project 1-2 cm out of the interchangeable unit (Fig. 22 a). At this point, tilt the unit
forward until the slanted bottom side is in flat contact with the lab table (Fig. 22 b). This forces the piston
into its correct position. Should the piston be forced somewhat too far into the glass cylinder, simply pull it
out and place it in the correct position according to the procedure described above.
Glass cylinder
Piston rod
Fig. 21
Piston rod
Fig. 22 a
Chapter 2 - Unpacking and first Operation
105