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VDL (E3.1) 10/2020 Page 25/196
• Power plug: Connection outside of a zone required
No classification, unprotected.
• Plug connection of the optional analog output: Connection outside of a zone required
No classification, unprotected.
• Electrical installation area, controller housing and heater area (preheating chamber) between the
inner and outer chamber: enclosure (overpressure, sweeping with compressed air)
Ex pzc Ignition protection Pressurized enclosure “p” per EN IEC 60079-2
Equipment protection level:
Increased protection "pzc", suitable for use in Zone 2 (chamber
housing as protection against an explosive atmosphere in the event of a fault)
II 3 G Ex pzc IIB T3 Gc
1.9 Intended use
Following the instructions in this operating manual and conducting regular maintenance work
(chap. 25) are part of the intended use.
Any use of the chambers that does not comply with the requirements specified in this Operating
Manual shall be considered improper use.
Other applications than those described in this chapter are not approved.
Use
VDL vacuum drying ovens are suitable for drying and heat treatment of solid or nonflammable pulverized
charging material, as well as bulk material, using the supply of heat under vacuum.
During this process, the contained solvent may be able to form an explosive mixture with air under normal
conditions. Ignition of an explosive atmosphere is prevented in the VDL vacuum drying ovens by various
safety measures. The maximum drying temperature lies by a standard safety factor below the maximum
permitted auto-ignition temperature. The drying temperature must lie below the sublimation point of the
loading material.
The VDL vacuum drying ovens are approved for drying of materials with organic solvents. This may cause
unlimited amounts of solvents to appear temporarily. The chambers are equipped with an explosion-proof
inner chamber.
The VDL vacuum drying ovens are not intended for installation in a Zone 1 or 0. The chamber must not be
installed or operated in an occasionally or continuously / for long periods / frequently potentially explosive
area. Measures must be taken to prevent the spread of explosive atmospheres to unprotected areas.
The chamber plug (power plug) is unprotected because it must be disconnected in case of an emergency
to completely separate the chamber from the power supply. Therefore, the electrical connection must be
established outside a zone.
Temperature class
The temperature class of the inner chamber according to IEC 60079-0 is T3. It depends on the maximum
operation temperature inside the oven. The auto-ignition temperature is determined from the safety speci-
fications of the solvent used. In the case of solvent mixtures, the solvent with the lowest auto-ignition tem-
perature as this is critical.
According to IEC 60079-0 the VDL vacuum drying ovens are NOT suitable for the temperature classes T4,
T5 and T6. Insert only substances with an auto-ignition temperature that is higher than 200 °C / 392 °F.
The information listed on the on the type plate.for explosion protection is essential for classification.
For the Device category, refer to the area classification information on the site of installation in Chap. 3.5
.
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