4.3.3 Controlled Pressure Reduction
Vacuum Controller NC 800:
This controlling profile can only be
set in H1 operating mode.
Start the process by pressing the
MAN key
System will evacuate to the pre-
set pressure setpoint
"Mode“ display shows status
"H1". If a post distillation
time is entered numerically,
the remaining time appears in
minutes flashing alternately
with "H1".
Defined post distillation accor-
ding to the entered values.
When the pressure has been
reduced:
- the controller switches off;
-display „mode“ shows „End“;
-asignal sounds ( 3 x 10 seconds)
-the vacuum valve closes, the
system remains under vacuum.
Press the STOP key to finish.
4.4 Temporary Mode
4.4.1 Function and Operation
In the temporary mode, you can
interrupt the current program at any
point, and enter a temporary vacuum
setpoint which is not retained.
Press DOWN key once:
The actual pressure is tempora-
rily set as pressure setpoint.
LED in MAN display flashes.
If the DOWN key is held pres-
sed, evacuation continues until
ultimate vacuum is reached. The
actual pressure will be temporarily
set as pressure setpoint. Once
contact is released from the DOWN
key the system will evacuate to the
momentary pressure setpoint.
By pressing the UP key the venting
valve is phased in and the pressure
in the system is increased.
By further pressing the UP key the
venting valve is opened three
times briefly and then as long as
the key is pressed.
Switching to temporary mode
occurs only after the venting
valve has been activated three
times.
Once contact is released from
the UP key the system will eva-
cuate to the momentary pressure
setpoint.
The temporary mode is stopped
by pressing the MAN-Key. The
system will regulate to the pre-
vious pressure setpoint.
4.4.2 Aeration during Distillation
Aeration is possible during manual
distillation:
Press AER key.
Short tapping of the key pro-
duces short venting.
Key held down: after 4 short
venting periods, the system is
continuously vented.
The indicated actual pressure
becomes the temporary setpoint,
the current pressure differential
value is retained.
After releasing the AER key the
system evacuates to the new
temporary setpoint.
To end the temporaray mode press
the MAN key.
The system will evacuate to the
previous pressure setpoint.
4.4.3 Experimental Use
Preset the pressure differential (h)
(see section 4.2).
Press MAN key.
Press and hold DOWN key (thereby
changing to temporary mode).
When desired level is indicated by
vapour, release the DOWN arrow
key.
The actual pressure is retained
as temporary pressure setpoint
automatically.
4.5 Uncontrolled Evacuation/
Drying Mode
This function is started in the manual
mode.
Press MAN key again
Regulation of the pressure set-
point is switched off and the
system will evacuate to the final
vacuum.
The display „mode“ shows „PU“.
Press the STOP key to finish the
evacuation.
5. Automatic Operation
The vacuum controller searches auto-
matically for the first boiling point and
retaines the value found as the pressu-
re setpoint. In addition, a reduction
gradient can be entered, as in manual
mode. The reduction process begins
once boiling point has been achieved.
5.1 Controlling Profiles
The following controlling profiles can
be carried out:
APressure Differential
(see fig. 6):
Rapid reduction of pressure down
to the first boiling point, which will
be found automatically.
Pressure Differential Operation.
B Controlled Pressure Reduction
(see fig. 7).
Rapid reduction of pressure down
to the first boiling point, which will
be found automatically.
From boiling point a gradual reduc-
tion of pressure; reduction rate can
be set by pressure reduction d and
post distillation time t.
Setting values:
see section 5.2
Running:
see section 5.3
Boling points above 600 mbar
must be started manually (see sec-
tion 4.4.3 Experimental Use).
The amount of liquid to be distilled
must be at least 20% of the piston
volume.
5.2 Setting Values
The following operational parameter
can be set for automatic operation:
- Pressure differential (h) for vacu-
um valve;
- pressure reduction (d);
- post distillation time (t).
The presssure setpoint has no
significance during automatic ope-
ration.
The "mbar" displays functions
6Translation of original Operating Instructions, english, KNF 121205-121650 02/10
