User manual

ALT-A02/PLT-A01-BA-e-1310 31
9 User Instructions
• To form a reproducible mean value several density measurement are necessary
• Remove fat from solvent-resistant sample / /glass sinker /beaker.
• Regularly clean sample dishes/glass sinker/glass beaker, do not touch immersing
part with your hands
• Dry sample/glass 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 tweezers.
• 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
measuring liquid (density modification of distilled 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 measuring liquid.
• To avoid great vibrations of the balance, place sample carefully.
• Avoid static charge, e. g. dry glass sinker with cotton cloth only.
• If the density of your solid only deviates slightly from that of distilled water, ethanol
may be used as measuring liquid. However, check beforehand whether the
sample is solvent-proof. In addition you must observe the applicable safety
regulations when working with ethanol.
• Handle glass sinker with care
(no warranty claims in case of damage).
• To avoid corrosion, don't leave the density set immersed in liquid for a long time.