Evacuation; Breaking The Vacuum (Flooding With Ambient Air); Operation With Inert Gas - Binder vdl 23 Operating Manual

14.1 Evacuation

• Close the aeration valve (5) and the fine dosing valve for inert gas (6).
• Turn on the vacuum pump.
• Turn the lever of the vacuum shut off valve (8) to
the "ON" position (valve open).
• Monitor the internal pressure on the pressure
display (3). The analog manometer displays the
running evaporation respectively the end of the
drying procedure. The scale of the manometer (3)
refers to an ideal ambient pressure of 1013 mbar
/ 29.9 inHg. Tolerance: 50 mbar / 37.5 mm Hg
(Torr) / 1.5 inHg (2.5% of the final scale value +
reading precision).
• When the desired end vacuum is obtained, turn
the VDL vacuum shutoff valve (8) to the "OFF"
position (valve closed). The reached vacuum is
now maintained.
The permissible end vacuum is 10
As long as there is a vacuum, never try to open the oven by force.

14.2 Breaking the vacuum (flooding with ambient air)

When the drying procedure is complete, the vacuum in the inner container is broken (flooded).
• Open aeration valve (5) and fine dosing valve for inert gas (6)
• As soon as aeration valve (5) is open, fresh air is sucked in through the fresh air connection (12).
When the fine dosing valve for inert gas (6) is open, fresh air is sucked in through the inert gas con-
nection (11).
Fresh air is introduced into the lower part of the rear panel of the inner chamber where it is evenly distrib-
uted in the inner chamber. This supply of fresh air by under-flooding prevents turbulence of pulverized
drying material.

14.3 Operation with inert gas

When operating the VDL vacuum drying oven with inert gas, correctly follow the technical ventilation
measures, as described in the DGUV guidelines 213-850 on safe working in laboratories (formerly
BGI/GUV-I 850-0, BGR/GUV-R 120 or ZH 1/119, issued by the employers' liability insurance association)
(for Germany).
During operation with inert gas, the chamber is supplied with an oxygen displacing gas (e.g. N
gases in high concentrations are hazardous to health. They are colorless and almost odorless and there-
fore practically imperceptible. Inhalation of inert gases can cause drowsiness up to respiratory arrest.
When the O content of the air decreases below 18%, there is risk of death from lack of oxygen. Any gas
2
that might escape has to be led out via good room ventilation or a suitable exhaust system.
VDL (E2.1) 05/2016
Figure 18: Manometer display
-2
mbar / 0.0003 inHg.
). Inert
2
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