BrandTech Scientific HandyStep S - Manual (Page 33)

English
Checking the Volume
1.
Preparation of the instrument
Fitting tip. This test can be carried out with PD-Tips of any size.
However, size 5 ml is most commonly used for this purpose.
2.
Carry out the test
a) Adjust the stroke setting of HandyStep ® S to Step 5 (10 % of
nominal volume).
b) Filling the PD-Tip, immersing it vertically into the testing liquid.
c) Discard the first step; it only serves to align the internal mecha-
nism.
d) Place the weighing vessel (containing a small amount of deionized
water) on a balance and tare the balance.
e) Dispense the second step into the weighing vessel. For this, push
down the dispensing lever at a steady rate to the stop and hold
it there. Then wipe the tip on the vessel wall over a distance of
approx. 10 mm.
f) Enter weighed value into test record.
g) Repeat points D to F 10 times.
(For the 10th volume test, the 5 ml PD-Tip with a stroke setting
of 5 has to be filled a second time – steps A through C.)
h) Repeat the same testing procedure at stroke settings 3 (6 % of
nominal volume) and 1 (2 % of nominal volume).
i) This results in a total of the 30 weighed values needed.
Depending on use, we recommend that gravimetric testing of the instru-
ment be carried out every 3-12 months. This time frame should be
adjusted to individual requirements. Gravimetric volume testing according
to DIN EN ISO 8655-5 is performed as follows:
33