Heidolph LABOROTA 4000 up to 4003 - Manual (Page 114)

Using the Laborota 4002 / 4003 control
112 Laborota 4000/4001 efficient, 4010/4011 digital, 4002/4003 control 1.02
6.4.2 p const mode
Use the Mode button to choose between three vacuum control modes. A LED
shows the currently active mode.
In p const mode, the vacuum is held constant at a given value. This setting is
especially suitable for all standard processes.
For distillation, that means:
- No temperature sensor required.
- The pressure must be adjusted manually during mixture distillation.
- Knowledge of thermodynamic material data is required.
Select the setpoint vacuum so that the boiling point of the substance to be
distilled is between the bath temperature and the temperature of the cooling
medium. Ideally, the difference between the bath temperature and boiling
temperature, and that of the boiling temperature and temperature of the
cooling medium, should each be 20 K.
Setting a value for Δp is superfluous when using the ROTAVAC vario control.
The display (Fig. 6-1 (14)) shows Set Δp: ----. Vacuum control is realised via
the speed of the pump.
The value of the differential gap (hysteresis) Δp indicates how much the
pressure may rise (in mbar) before the vacuum valve is opened.
High hysteresis leads to high loss rates due to increased gas transport.
Set Δp so that the valve does not activate too often.
For low boilers we recommend Δp values of 5–10 mbar, for high boilers
1–5 mbar.
1. Press Mode (Fig. 6-1 (12)) until Mode p const LED is lit.
2. Press
Select
(Fig. 6-1 (15)) until Set Vac LED is lit.
3. Use the arrow buttons (Fig. 6-1 (9)) to set the required vacuum.
The vacuum setpoint is visible on the display (Fig. 6-1 (14)).
VAC Senso T:
4. Press
Select
(Fig. 6-1 (15)) until Set Δp LED is lit.
5. Use the arrow buttons (Fig. 6-1 (9)) to set the desired differential gap
(hysteresis) Δp.
Selecting p const
mode