Metrohm 807 Dosing Unit - Manual (Page 42)

4.1 Care and upkeep
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34 ￭￭￭￭￭￭￭￭
807 Dosing Unit
3 Place the dosing unit with the dosing cylinder in water (possibly with
a small amount of dishwashing detergent) for a few minutes.
4 Carefully release the cylinder base from the distributor by hand (with-
out rotating it) in order to separate the two discs from one another.
If the discs cannot be separated this way, inform the Metrohm Ser-
vice Dept.
Should it happen that the discs repeatedly adhere to one another, then
the contact surfaces of the valve disc and the distributor disc can be
greased with a small amount of paraffin grease 6.2803.010. This is how-
ever not to be generally recommended.
4.1.4 Resistance and materials
4.1.4.1 Solvent
Conventional reagents and media can be dosed without difficulty with the
807 Dosing Unit. The materials of the individual components (see Chapter
4.1.4, page 34) used which come into contact with the liquid being dosed
have been selected for maximum resistance to chemicals and functional-
ity.
It can however not be assumed that all types of aggressive or high-con-
centration reagents can be conveyed without difficulty. It is the responsi-
bility of the user to determine the resistance of the various individual com-
ponents to specific, aggressive media.
WARNING
Reagents which corrode glass, e.g. hydrofluoric acid HF or strong inor-
ganic alkalis, should be applied in diluted concentrations only. Caution
is also called for with concentrated solutions which are subject to crys-
tallization.
Many problems involving aggressive media can be prevented by regular
cleaning and inspections. It is possible that frequent replacement of the
cylinder unit (piston/cylinder/cylinder base with valve disc) will be required.
The temperature of the dosing material may not exceed 50°C. The dosing
unit and its components cannot be autoclaved. The sterility of a germ-free
dosing material cannot be guaranteed.