KERN KERN YDB-03, Руководство по эксплуатации

Страница: 115 / 115

YDB-03-BA-e-2114 115
9 User Instructions
•
To form a reproducible mean value several density measurement are necessary
•
Remove fat from solvent-resistant sample / sinker / glass beaker.
•
Regularly clean sample dishes/ sinker/glass beaker, do not touch immersed part
with your hands
•
Dry sample/ sinker/pincers after each measurement.
• Adjust sample size to sample dish (ideal sample size > 5 g).
•
Only use distilled water.
•
When immersing for the first time, lightly shake sample dishes and sinker, in order
to dissolve air bubbles.
•
Always ensure that, when re-immersing into the liquid no additional bubbles
adhere; it is better to use pincers to place the sample.
•
Remove firmly adherent air bubbles with a fine brush or a similar tool.
•
To avoid adherent air bubbles smoothen samples with rough surface.
•
Take care that no water drips onto the upper sample dish when weighing with the
help of pincers.
• In order to reduce the surface tension of water and the friction of the liquid on the
wire, add three drops of a common detergent (washing-up liquid) to the aid liquid
(density modification of dist. water occurring due to the addition of tensides can
be ignored).
•
Oval samples can be held more easily with pincers when you cut grooves into
them.
•
The density of porous solids may only be determined approximately. Buoyancy
errors occur when not all the air is eliminated from the pores during immersion in
the aid fluid.
•
To avoid great vibrations of the balance, place sample carefully.
• Avoid static charge, e. g. dry sinker with cotton cloth only.
•
If the density of your solid only deviates slightly from that of distilled water, ethanol
may be used as aid liquid. However, check beforehand whether the sample is
solvent-proof. In addition you must observe the applicable safety regulations
when working with ethanol.
•
To avoid corrosion, don't leave the density set immersed in liquid for a long time.