Mirror Polished Sifter, Doebritz Rotary Airlock, 30 m³/hr / ATEX Zone 21
Doebritz Mirror Polished Sifter: ATEX certified, <0.05% air leakage, CNC-machined rotor. Ideal for food-grade & explosive dust. OEM supply. Get quote.
Product Summary
Engineered for ultra-hygienic and high-containment applications, the Doebritz Mirror Polished Sifter combines mirror-finished stainless steel surfaces with true airlock integrity. This rotary valve achieves a discharge capacity up to 35 m³/hr, handles differential pressure up to 1.5 bar, and is fully ATEX Zone 21 certified for explosive dust environments (St2). Designed for powders, pellets, and friable flakes, it delivers minimal product degradation and <0.05% air leakage at 1 bar.
Why Source Doebritz Mirror Polished Sifter
- Mirror-Finished Hygienics: Ra ≤0.4µm sanitary surface eliminates product adhesion and bacterial growth, reducing cleaning cycles by 40%.
- Certified Explosion Proof: Full ATEX II 2D c T120°C certification with grounded rotor and anti-static seals for safe pneumatic conveying.
- CNC Precision Sealing: Double-lip PTFE or FDA silicone seals achieve ≤0.03% volumetric air leakage rate, verified by independent test bench.
- Global OEM Supply Chain: Drop-in replacement for Coperion, Zeppelin, and Schenck systems. Custom flanges (DIN, ANSI, JIS) available 5-7 days lead time.
- 30-Year Casting Heritage: Investment-cast SS316L housing with 100% X-ray inspected wall thickness, no porosity or micro-leaks.
Housing & Rotor Engineering
The Doebritz Mirror Polished Sifter features a one-piece investment cast stainless steel housing with integral end covers, eliminating weld seams that trap contaminants. The 10-vane open rotor design is precision balanced to G2.5 (ISO 21940) and CNC-machined with a 0.08mm tip-to-housing clearance — critical for both airlock efficiency and gentle powder handling. Outboard-mounted, grease-lubricated bearings isolate the product zone from lubricants, while a triple-seal shaft arrangement (compressed air purge + PTFE lip + V-ring) guarantees zero fugitive emissions for pharmaceutical or food duty.
Technical Specifications
All data verified under actual differential pressure of 1.0 bar (15 PSI) with calcium carbonate powder (d50=15µm).
| Specification | Detail |
|---|---|
| Body Material | SS316L investment casting (mirror polished, Ra≤0.4µm) |
| Rotor Design | 10-vane open rotor, CNC machined, tip clearance 0.08mm |
| Inlet/Outlet Size | DN150 (6 inch) round, custom ANSI/DIN/JIS available |
| Capacity (rotary) | 15 – 35 m³/hr at 20 RPM (dependant on powder bulk density) |
| Max Differential Pressure | 1.5 bar (21.7 PSI) |
| Air Leakage Rate | ≤0.05% of conveying volume at 1 bar (tested) |
| Temperature Range | -20°C to +180°C (PTFE seals), +350°C optional |
| ATEX Certification | II 2D c T120°C (dust Zone 21) | II 2G optional |
| Shaft Sealing | Triple seal: air purge + PTFE lip + V-ring |
| Bearings | Outboard, grease-lubricated, life 40,000 hours |
Heavy-Duty Application Scenarios
Pneumatic Conveying Systems
Installed as a pressure-tight rotary feeder for dilute or dense phase systems conveying cement, plastic pellets, or lactose. Maintains system vacuum/pressure stability with pulsation-free discharge.
Silo Discharging with Bridging Prevention
The mirror-polished internal cone and variable frequency drive (VFD-ready) rotor prevent arching and bridging in hygroscopic materials like titanium dioxide or food starch.
Dust Filter Collectors
As a high-sealing rotary airlock under dust collectors (baghouse / cyclone), the Doebritz valve achieves <0.5 mbar cross-leakage, maximizing filter efficiency and reducing compressed air pulsing cycles.
Frequently Asked Questions
- Q1: What is the maximum operating temperature for your Mirror Polished Sifter?
- A: Standard PTFE seals support -20°C to +180°C. For high-temperature applications up to +350°C (e.g., hot calcined powder), we offer graphite laminate seals and a water-cooled bearing housing option. Please specify your process temperature in the RFQ.
- Q2: Can Doebritz manufacture non-standard inlet/outlet flanges?
- A: Absolutely. While we stock DIN 2576 PN10 and ANSI 150# flanges, we support custom drilling patterns, square flanges, or tri-clamp connections for sanitary lines. Minimum order for custom flange: 5 pieces, lead time 10 working days.
- Q3: Is the ATEX certificate valid for both gas and dust?
- A: The Doebritz Mirror Polished Sifter carries EC-type examination certificate for dust explosive atmospheres (ATEX II 2D). For gas (G) applications with Zone 1 or 2, we provide a separate ATEX II 2G version with spark-resistant rotor (copper/aluminum alloy). Please confirm your zone classification.
- Q4: What’s your lead time for a complete rotary valve with motor and VFD?
- A: Standard stainless steel models (DN100 to DN300) are 15-18 working days ex-works. For cast iron with special rotor coatings (nickel or tungsten carbide), lead time extends to 25 days. Express delivery (7 days) available for EU stock items – contact our sales team for current inventory.
- Q5: How do you verify the mirror polish quality and air leakage rate?
- A: Each unit undergoes three checks: (1) Surface roughness measurement (Ra value, 5 points on housing bore), (2) 100% borescope inspection of internal welds and edges, (3) Dry air leakage test at 1 bar differential for 30 minutes – we provide a signed test certificate with each shipment. Leakage rate guaranteed ≤0.05% of conveying air volume.
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