Velp Scientifica OV 725 Digital Manual De Instrucciones página 11

This will prevent part of the sample from remaining on the walls of the container and therefore not being homogenized.
Keep in mind that the insertion of the tool into the receptacle causes the liquid level to rise.
Position of the dispersing tool
•
Place the dispersing tool not in the middle of the receptacle (Figure 1)
•
Place the dispersing tool about 1/3 of the sample height from the bottom of the receptacle (Figure 2).
Figure 1
If you use a dispersing tool that is too large for the sample amount, it could suck air.
Dispersing speed
Always start at a low speed, then gradually increase it. This allows to keep control of the process.
Normally the dispersion occurs in 30 – 60 seconds, if this does not happen, check:
•
The dispersing tool position in the container
•
If the sample is too viscous
•
Incorrect dispersing tool for the sample (size, type)
TO NOT REDUCE THE LIFETIME OF THE DISPERSING TOOL AND THE DISPERSER
Never run the dispersing tool without liquid
The dispersing tool requires a liquid sample for the lubrification of the gasket during machining.
A PTFE gasket is placed between the rotor and stator to prevent the rotor from bending or moving inside the tool. The
gasket must be immersed in the liquid sample, otherwise it will burn causing overheating and subsequent damage to the
sample and the dispersing tool.
Without the liquid, the PTFE gasket can burn causing damage to the tool and the disperser.
Cleaning and maintenance of dispersing tool
It's necessary to disassemble and wash the dispersing tool after each use, checking the good condition of the gasket and
the metal parts and replacing them if necessary. The PTFE gasket is naturally subjected to wear because of the friction with
the rotating elements of the tool; therefore it's necessary to periodically replace it in order to guarantee the correct operation
of the tool and the dispersing instrument.
Replace the PTFE gasket if the following conditions occur:
•
Visible wear of the component (e.g. deformations, thinning),
•
Unusual noise and vibration during the operation of the dispersing instrument,
•
When the space between the gasket and the internal and external metal parts is excessive.
To disassemble the dispersing tool, use the appropriate tool disassembly kit supplied with the drive unit and read the
instruction manual supplied with each tool.
Figure 2
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