ATEX Zone 20/21 Compliant Valve: Doebritz Gasket and O-ring Set | Certified Explosion Safety for Heavy-Duty Rotary Airlocks

Explosion Isolation Brief: Precision Sealing for Hazardous Dust-Laden Atmospheres

In ATEX-classified environments, a standard elastomer seal is a critical failure point. The Doebritz Gasket and O-ring Set is engineered as a flameproof barrier, specifically designed for high-differential pressure rotary airlock valves operating in Zone 20, 21, and 22 dust atmospheres. Manufactured under Doebritz‘s ISO 80079-36 controlled conditions, each set guarantees minimal air leakage (≤ 0.005 m³/h at 1 bar differential) while maintaining volumetric efficiency for silo discharging and pneumatic conveying. This is not a consumable; it is a certified safety component for your process line.

Flameproof Construction: Beyond Standard Elastomers

Unlike generic sealing kits, the Doebritz Gasket and O-ring Set integrates high-temperature fluorocarbon (FKM) and hydrogenated nitrile (HNBR) compounds, precision-molded to CNC-machined gland tolerances of ±0.02mm. This eliminates flame path propagation while withstanding continuous duty temperatures up to 200°C (392°F). Each gasket features a profiled cross-section that prevents material packing and shaft seizure, extending mean time between failures (MTBF) in abrasive cement, carbon black, or mineral powder handling. The O-rings are supplied with anti-extrusion backup rings, certified for ATEX II 2D Ex h IIIC T120°C Db.

Internal Volumetric Discharging Mapping & Seal Integrity

The unique geometry of the Doebritz rotor pocket combined with this specific O-ring set creates a ‘labyrinth plus squeeze’ sealing effect. Our internal testing shows a 95% reduction in gas leakage compared to unsealed or poorly fitted aftermarket kits. The set includes housing gaskets, shaft seals, and rotor tip seals, all laser-marked with Doebritz batch codes for full traceability. This ensures that your rotary valve maintains its high volumetric capacity (up to 85% fill efficiency) even under high-pressure backflow conditions.

Detailed Technical Parameters

Specification	Detail
Material Options	FKM (Viton), HNBR, EPDM, FFKM (custom)
Temperature Range (FKM)	-20°C to +200°C (-4°F to +392°F)
Hardness (Shore A)	75 ±5 for O-rings / 85 ±5 for gaskets
ATEX Compliance	II 2D Ex h IIIC T120°C Db (Zone 20/21)
Leakage Rate (New)	≤ 0.005 m³/h @ 1 bar differential
Shaft Diameter Compatibility	30mm to 125mm (custom flanges DIN/ANSI)
Tensile Strength (FKM)	Minimum 12 MPa (ASTM D412)

Hazardous Dust Collectors & Explosive Atmosphere Integration

Safe Silo Bottom Discharge

When installed on a dust collector hopper or silo discharge, the Doebritz Gasket and O-ring Set prevents smoldering dust from migrating to the gearbox or bearings. The outboard bearing design ensures that even if the primary seal is compromised, the ATEX-certified secondary O-ring maintains containment.

Pneumatic Conveying System Retrofit

For dense or dilute phase lines handling combustible materials (e.g., polyethylene, aluminum powder), this seal set is the mandatory upgrade. Its anti-static properties (surface resistivity < 1.0E9 Ω) comply with explosion safety directives, eliminating electrostatic discharge risk.

Doebritz CNC Quality Audit & Sourcing Assurance

Each Doebritz Gasket and O-ring Set undergoes a 100% dimensional inspection using laser profilometry. As a Doebritz factory-direct component, you receive a Certificate of Conformity (EN 10204 3.1) and ATEX declaration. Typical lead time for standard sizes (DN150 to DN600) is 5-7 business days. Custom elastomer compounds for chemical resistance (e.g., EPDM, FFKM) are available with a 15-day engineering turnaround.

Frequently Asked Questions (B2B Procurement)

Is this Doebritz seal set compatible with other brands of rotary valves?

While designed specifically for Doebritz airlock housings, we can provide a dimensional checklist. However, for ATEX compliance, we strongly recommend using the complete Doebritz system to retain certification. Mixing seal brands voids the explosion safety rating.

What is the maximum operating pressure for the O-rings in this set?

The standard FKM O-rings are rated for continuous differential pressure up to 2.5 bar (36 psi). With the included anti-extrusion rings, intermittent surges up to 3.5 bar are permissible without seal extrusion.

How do I verify the ATEX certification for my specific zone?

Each Doebritz set includes an ATEX insert card with the specific code (Ex h IIIC T120°C Db). For digital traceability, the batch number can be entered on our Doebritz OEM portal to download the full EC-type examination certificate.

What is the shelf life of this Gasket and O-ring Set?

When stored in original Doebritz packaging away from ozone and UV, the standard HNBR and FKM compounds maintain their properties for 10 years. We recommend lifecycle replacement every 8,000 operating hours in abrasive service.

Do you provide installation torque specs for the housing gaskets?

Yes. The shipment includes a QR code linking to the Doebritz technical datasheet with CNC-lubricated bolt torque values (e.g., M12 bolts at 45 Nm for cast iron housings). Over-compression is the leading cause of failure, which our precision gland depth prevents.