Operating instructions

78 METTLER TOLEDO DE40/50/51 Density Meter
15. Automatic sampling pump ASU-DE (optional)
This optional automatic sampling unit replaces the air pump that comes with the basic
installation. With its membrane pump it allows to aspire samples of low to medium viscosity
(at the max. ca. 1000 mPa·s) directly into the measurement tube, to empty, rinse and dry it
after the measurement.
The sequence described in section 8.5, used to control this routine, allows to eliminate
operator specific influences on the measurement which usually occur when using a syringe.
This option allows you to get reproducible results, regardless of the operator using the
instrument.
This pump is also required together with the DCU-300B auto rinsing unit, the SOP40 and
SOP50 and the CHG-260B sample changer.
Instead of using the standard waste bottle of the ASU-DE you can also use the automatic
draining unit AD-510.
15.1 Safety measures
Measures for your safety
- Make sure to switch off the DE40, DE50 or DE51 and disconnect the power cable before
installing the automatic sampling pump ASU-DE!
- Make sure that the solvents used to rinse the measurement tube do not form dangerous
mixtures or reactions when combined with the sample solutions or other solvents, since all
solutions are dejected into the same waste bottle!
- Connect the exhaust tube to a system capable of disposing of poisonous or corrosive gases!
Measures for operational safety
- Empty the waste bottle (drain pot) before it is filled to the rim! Otherwise the waste solution
is sucked into the pump and ejected through the exhaust. This could even damage the pump.
- The material in contact with the liquid for sampling is made of glass, Teflon or carbon. Do
not use any sample that may corrode the material.
Samples of high viscosity cannot be aspirated. Maximum viscosity that can be pumped is
approximately 1000 mPa-s.
Automatic sampling pump