Delfin MTL 451 1/2D INERT
Single-phase ATEX vacuum for Zone 21 with INERT neutralisation bath -- brushless motor for intensive use, 15 L total tank in AISI 304
- Ammunition manufacturing in ATEX Zone 21-classified facilities
- 3D printing with reactive metal powder (aluminium, titanium) in Zone 21
- Light-metal machining in aerospace and defense
- Powder metallurgy with magnesium or zirconium in ATEX zones
- Process plants with pyrophoric metal powders and Zone 21 classification
- ATEX Directive 2014/34/EU -- II 1/2D Ex h tb IIIC T80°C (Int) /T95°C (ext) Da/Db
- EN 17348:2022 (harmonized March 2023)
- IEC 60335-2-69 (industrial vacuums)
Delfin MTL 451 1/2D INERT
The Delfin MTL 451 1/2D INERT is the ATEX-certified brushless sister to the 452 ACD INERT: same neutralising AISI 304 liquid bath, same HEPA H14 final filter, but now with notified-body certification for ATEX Zone 21 with internal Zone 20 (II 1/2D Ex h tb IIIC). The single-phase brushless motor (1.1 kW) is built for continuous operation without brush wear and delivers 215 m³/h airflow at 221 mbar. Used where both reactive metallic dust and ATEX-classified area require simultaneous protection -- for example ammunition manufacturing, 3D printing with metal powder in ATEX zones, and light-metal machining in aerospace.
Applications
- Ammunition manufacturing in ATEX Zone 21-classified facilities
- 3D printing with reactive metal powder (aluminium, titanium) in Zone 21
- Light-metal machining in aerospace and defense
- Powder metallurgy with magnesium or zirconium in ATEX zones
- Process plants with pyrophoric metal powders and Zone 21 classification
Technical specifications
| ATEX marking | II 1/2D Ex h tb IIIC T80°C (Int) /T95°C (ext) Da/Db |
|---|---|
| Internal / external zone | 20 / 21 |
| Motor type | 1-faset brushless-motor (1,1 kW) |
| Duty cycle | Periodic |
| Airflow | 215 m³/h |
| Vacuum | 221 mbar (2250 mmH₂O) |
| Container | 15 L |
| Sound pressure | 74 dB(A) |
| Filter class | H class |
| Filter type | HEPA H14 (EN 1822-5), 99,995 % MPPS, 11.000 cm² filterflade |
| Primary filter | Stjerne/taske polyester ANT M-klasse antistatisk, 20.000 cm², diameter 420 mm |
| Cleaning system | Manuel filterrensning + indikator for tilstopning |
| Collection system | INERT neutralisation bath |
| Material | Lakeret staalkonstruktion, AISI 304 INERT-beholder |
| IP class | IP64 |
| Power | 1.1 kW |
| Current | 8 A |
| Voltage | 115/230 V / 50-60 Hz |
| Inlet | Ø 50 mm |
| Dimensions (L × W × H) | 610 x 660 x 1330 mm |
| Weight | 52 kg |
INERT TECHNOLOGY — EN 17348:2022
What is an INERT vacuum cleaner?
Delfin's INERT vacuum cleaners are built to collect reactive metallic dust — the kind of dust that can self-ignite or react violently with oxygen, heat or water. Instead of collecting dust dry in a bag or container, the vacuum channels it directly into a neutralising liquid bath (typically water with a passivating agent added), where the reactive metal particle is inactivated on the spot. That is the difference between a controlled process and a vacuum that can itself become the ignition source.
Tested to EN 17348:2022
The INERT range is certified and performance-tested to EN 17348:2022, the harmonized European standard for industrial vacuum cleaners in ATEX zones. The test confirms that the neutralisation system actually inactivates reactive dust under real operating conditions — not merely in a lab setup. Combined with HEPA H14 final filtration (99.995 % efficiency at MPPS per EN 1822-5), the exhaust is clean down to the finest health-hazardous particles.
Typical applications
INERT vacuums are used at shooting ranges (lead dust and primer residue from cartridges), in ammunition manufacturing, for 3D printing with metal powders (aluminium and titanium are highly reactive when finely divided), in light-metal machining in aerospace and defense, and at process plants where pyrophoric powders such as zirconium and magnesium are handled. Some models are ACD-certified (IEC 60335-2-69 Annex AA) for non-ATEX-classified areas, others are ATEX-certified for Zone 20, 21 or 22 — but they all share the same neutralising liquid bath and the same uncompromising filtration.
INERT versus conventional HEPA filtration
A conventional HEPA vacuum retains particles in a filter but leaves them dry and potentially reactive. With reactive metallic dust that is not enough — the particle may react with oxygen (exothermic oxidation) or moisture (hydrolysis of certain metal hydrides) and disrupt the collection process itself. INERT technology solves this by inactivating the particle at the moment of collection: dust is immersed in the liquid before it can react, and the HEPA H14 filter then captures any residual aerosol before exhaust.
Questions and answers
What does INERT mean in this context?
INERT denotes a vacuum cleaner with a neutralising liquid bath in the collection tank. Dust is channelled directly into the liquid and inactivated immediately, so it cannot react with oxygen, heat or sparks. The technology is developed for reactive metallic dust (aluminium, titanium, magnesium, zirconium, lead dust from shooting ranges), where conventional dry collection would itself be an ignition source.
Is the INERT system tested to EN 17348:2022?
Yes. The entire Delfin INERT range is performance-tested to EN 17348:2022 -- the harmonized European standard for industrial vacuum cleaners in ATEX zones. The test confirms that the neutralisation bath actually inactivates reactive dust under real operating conditions, not just in a lab setup. Documentation available on request.
What types of dust is INERT technology intended for?
Reactive metallic dust: aluminium and aluminium alloys, titanium, magnesium, zirconium, fine iron powder, lead dust and primer residue from shooting ranges, and pyrophoric powders from aerospace and defense. For non-reactive dust (organic process dust, plastics, etc.) the INERT technology adds no further safety -- a standard ATEX or ACD model without liquid bath is selected instead.
How does the HEPA H14 final filter work together with the liquid bath?
The neutralisation bath inactivates dust at the moment of collection, but there will always be a fine aerosol fraction that passes the liquid surface. The HEPA H14 filter captures 99.995 % of particles down to 0.3 micrometres per EN 1822-5 (MPPS method) before exhaust. The combination secures both safe collection (no reactive dry particle) and clean exhaust (no health-hazardous aerosol). The filter is Included/Incluso as standard on all INERT models.
Why brushless motor instead of bypass motor?
The brushless motor has no brushes, no sparks from the commutator and requires no motor-level maintenance. It is therefore built for continuous operation in ATEX zones, where every ignition source must be eliminated. The bypass motor (as on the 452 ACD INERT) is cheaper and delivers higher airflow, but requires periodic brush replacement and suits periodic duty in non-ATEX areas. The choice between brushless and bypass follows the zone: ATEX = brushless, ACD = bypass.
What does II 1/2D Ex h tb IIIC T80°C (Int) /T95°C (ext) Da/Db mean?
The marking has four parts: (1) II 1/2D -- equipment group II, category 1 internal (Zone 20 inside the tank) and category 2 external (Zone 21 outside). (2) Ex h tb IIIC -- protection method h (combined prevention) and tb (tank barrier), dust group IIIC (conductive dust). (3) T80°C (Int) /T95°C (ext) -- maximum surface temperatures. (4) Da/Db -- equipment protection level 'Da' internally and 'Db' externally. The machine is thus suited to a setup where Zone 21 is classified outside, but internal volumes correspond to Zone 20.