Buchi B-720 - Page 13

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BÜCHI Vacuum Controller B-720 5 Operation
5.5 Working example
The values in the following example apply for the distillation of
ethanol. For the values of other solvents, please consult the
table at the end of this section. Check the following items before
each distillation:
• Cooling water connected
• All the electrical connections OK
• All the hose connections OK
• Vacuum source connected
If there is any foaming or severe splashing, it is possible to
intervene directly with «UP»/«DOWN» Hold state.
Press the «START» key for the distillation to continue, i.e. the
system will operate at the set desired pressure.
«STOP» 957 • The system is ventilated (the ventilation valve remains open)
(current system pressure) • The LED «STOP» lights up
• The cooling water valve remains open for about another 5
min.
Press «STOP» 2 x 957 • Press «STOP» twice for the cooling water to switch off
briefly (current system pressure) immediately
Table 6: Working example
«UP» Current system pressure • System is ventilated for as long as the key is kept depressed
• When the key is released, the pressure is adjusted to the new
set-point value.
• The LED «START» flashes.
«START» Current system pressure • The system is evacuated to the initial set-point value
• When «START» is released, the pressure is adjusted to the
current value.
• The LED «START» lights up.
Action Display Function
Distillation «ON» switch 957 • The system pressure is displayed.
of ethanol (current system pressure)
«P» 147 • The desired pressure is displayed and can be varied with
(desired pressure) «UP» and «DOWN» (1 mbar-atmospheric pressure).
«욼P» H 16 • The hysteresis displayed.
«DOWN» key until H 5 • Set hysteresis 5.
desired hysteresis is set
«START» 957 • The system is evacuated to the preselected desired value of
72 72 and is conntrolled there within the set hysteresis of 5.
(current system pressure)