Metrohm 711 Liquino - Manual (Page 147)

6. Appendix
711 Liquino, Instructions for use 141
Port 0 – is used for venting the storage vessel and is usually fitted with an absorber
tube (filled with a drying agent).
Port 1 – is side-mounted and its standard definition is as the dosing outlet.
Port 2 – is located on the lower surface; its standard definition is as filling inlet and
it is normally fitted with a dip tube.
Port 3 – is side-mounted and has no standard definition.
Port 4 – is located on the lower surface; its standard definition is as air inlet open-
ing when the tubing system is being emptied.
6.1.1 Preparing and emptying the dosing units
When the reagent is changed or if the dosing unit has not been used for a
long time the dosing cylinder and the dosing unit tubing must be rinsed. If
allowed to stand for a long time gas bubbles may form in the dosing cylin-
der. This can be traced back to leaking or badly tightened tubing connec-
tions or to the release of dissolved gases from the liquid.
Always carry out PREP before starting!
In order to achieve the highest possible precision during dosing it is an
absolute necessity that the liquid filling the dosing cylinder and tubing sys-
tem of the dosing unit is bubble-free.
In order that you do not have to carry this out manually by repeatedly filling
and emptying the dosing unit the Metrohm dosing and titrating devices are
equipped with the comfortable '
PREP' function (<PREP> key). By carrying
out an automated run in several steps the optimal amounts of regent solu-
tion (depending on cylinder and tubing dimensions) are aspirated; the tub-
ing rinsed and filled bubble-free.
• If you want to work with a particular mode then select this mode
(<MODE> key) and carry out the necessary settings. If you want to work
with a stored method then load this method (<USER METHOD> key or
<MEM CARD>). If you want to dispense or dose manually switch to
manual operation with the <MANUAL> key. Depending on the selected
mode the PREP function may be carried out differently. The occupancy
of the Dosino ports can also be different. If a SEQ method in which sev-
eral Dosinos are used is loaded then all the dosing units required are
prepared one after the other.
• Hold the tip of the connected tubing in a waste beaker
• Press <PREP>.
• You can now select (except in XDOS mode) whether excess reagent so-
lution should be emptied during the PREP run via the dosing tip
(Port 1) or into the storage bottle (Port 4). This is done by pressing key
<1> or <2>.
• When the dosing cylinder is empty the cylinder and all the connected
tubing is rinsed and filled with reagent solution.
• If special port occupancies have been defined in the XDOS mode they
will be used.