Metrohm 807 Dosing Unit - Manual (Page 26)

3.5 Mounting the dosing unit onto the bottle
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807 Dosing Unit
3.5.3 Buret tips
The following buret tips are included in the standard equipment of the
dosing unit:
6.1543.200
6.1543.060
Open dosing tip 6.1543.060
For tasks during which the top is not immersed, e.g. dosings.
The buret tip can be stored in the same solvent as the one contained in
the reagent in order to prevent reagent crystallization.
We recommend that the storage vessel be filled with solvent and that the
buret tip be placed inside it. In the event that KF reagent is used as the
titrant, use methanol or ethanol for storing the dosing tip.
Antidiffusion tip 6.1543.200
It is used for work requiring the immersion of the tip, e.g. titrations.
This tip prevents the diffusion of liquids into the buret tip.
The pressure of the surrounding liquid and the internal stress of the mem-
brane press on the tubing end, thus sealing off the opening.
The backpressure of the dosed liquid is overcome during the dosing proc-
ess. The membrane opens up the tubing end. The tubing end is sealed off
again automatically after the dosing is completed.
CAUTION
Do not disassemble the antidiffusion tip.