Metrohm tiamo 2.4 Manual - Manual (Page 1185)

￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
5 Method
tiamo 2.4
￭￭￭￭￭￭￭￭ 1169
Filling times
Filling times are not included in the calculation of the dosing rate. The fill-
ing times (including valve switching) can be estimated according to the
following formula:
Filling time in s = (max. filling rate/current filling rate) • t + 4 s
t = 20 s (for exchange units) or 18 s (for dosing units)
The maximum filling rate is dependent on the cylinder volume of the
exchange/dosing unit that has been put into use. The approximate filling
times (including valve switching) are given In the table below for various
cylinder volumes (exchange and dosing unit) at different filling rates:
Cylinder volume Filling time in s
max. 100 mL/min 50 mL/min 10 mL/min
1 mL 24/--- --- --- ---
2 mL ---/22 --- --- ---
5 mL 24/22 --- --- 34
10 mL10 mL 24/22 --- --- 64
20 mL 24/22 --- 28 124
50 mL 24/22 34 64 304
Example
1 L reagent is to be dosed within 1 hour with a 50 mL exchange unit.
What is the dosing rate?
Total duration = 60 min
Dosing volume = 1000 mL
Filling time = 24 s (at max. filling rate)
Cylinder volume = 50 mL
Number of refillings = dosing volume/cylinder volume = 1000/50 = 20
If the division gives a whole number, the last filling is no longer a refilling
and must be deducted. In our example, 19 refills are necessary. There is
no dosing during this time, i.e. the net dosing time is
3600 s - 19 × 24 s = 3144 s = 52.4 min
The dosing rate is thus
1000 mL/52.4 min = 19.1 mL/min
Summary in a formula: