BUCHI Encapsulator B-395 Pro - Manual (Page 48)

6 Operation
48 B-395 Pro Operation Manual, Version C
4. Set the pumping speed and the vibration frequency to the values you determined that creates
a good, clear bead chain. Activate the electrostatic dispersion unit at 300 V and increase the
voltage by steps of 100 V until the one-dimensional bead chain is transformed into a funnel-like,
multi-line stream. The higher the electrostatic charge, the earlier the bead chain will separate.
This prevents the beads from hitting each other in flight and from hitting each other as they enter
the hardening solution since they are now like charged particles that repel each other. With this
exclusive feature, the Encapsulator can routinely generate bead batches with homogeneity greater
than 95 %.
5. Change the vibration frequency and the pumping speed and observe their influence on the
electrostatic voltage needed to generate the bead stream separation. The use of the electrostatic
dispersion unit enlarges the working range.
It can happen that after some time the beads no longer enter the receiving beaker or actually
jump out of it. This is due to the fact that electrostatic charges have accumulated in the electrically
isolated beaker. To avoid this phenomenon, place the supplied stainless steel clip of the grounding
wire over the edge of the beaker so it extends into the receiving liquid and connect the other end
of the green-yellow wire to the grounding plug on the front panel of the control unit (see figure 6-4).
If you work with the complete reaction vessel, then the electrostatic charges will be automatically
eliminated without the need of the grounding wire.
Figure 6-4: Grounding the open polymerization bath
6. Change the amplitude of the vibration and you will observe only slight changes in the bead chain.
In general, values between 1 and 3 are optimal for low viscous solutions. If immobilization mixtures
with high viscosity (> 150 mPa s) are used, values higher than 3 might be more appropriate.
7. Repeat this experiment with another nozzle size.