Doebritz PTFE Star discharge valve | Heavy-Duty Rotary Airlock Valve with PTFE Lining & ATEX Certification
Doebritz PTFE Star discharge valve: Heavy-duty rotary airlock with PTFE lining, ATEX Zone 20/21, 0.1-0.2mm clearance, and CNC precision. Ideal for corrosive powders. OEM supply.
Product Snapshot: Doebritz PTFE Star Discharge Valve for Corrosive Bulk Solids
Doebritz introduces the PTFE Star discharge valve (model DBR-1237 platform) – a heavy-duty rotary airlock engineered specifically for highly corrosive, abrasive, and sticky powders. Unlike standard unpainted or painted carbon steel valves, this unit features a full PTFE (polytetrafluoroethylene) lining on all product-contact surfaces, combined with CNC-machined 316L stainless steel internals. The result is a star discharge valve that resists chemical attack, prevents material build-up, and maintains minimal air leakage (0.1–0.2 mm radial clearance) even in aggressive pneumatic conveying or gravity discharge lines. Backed by Doebritz‘s 15+ years of heavy industrial manufacturing, this valve delivers superior total cost of ownership for plant maintenance and global OEM supply projects.
Why Plant Sourcing Chooses Doebritz PTFE Star Discharge Valve (Minimal Leakage + Corrosion Resistance)
- PTFE Lined Product Zone: Full PTFE coating on housing and rotor pockets – resists HCl, HF, solvents, and acidic powders. No metallic contact with aggressive bulk solids.
- Precision Sealing & Airlock Efficiency: Rotor-to-housing clearance held to 0.1–0.2 mm via Doebritz‘s 5-axis CNC machining. Achieves < 0.2 m³/h air leakage at 0.6 bar differential – ideal for dense phase conveying.
- ATEX Certified Explosion Safety: Compliant with Zone 20/21/22 dust explosion protection. Flameproof design with 16 bar pressure shock resistance and anti-static PTFE grade.
- Heavy-Duty Outboard Bearings: Isolated from product zone – prevents bearing contamination and extends MTBF > 25,000 hours.
- Quick-Clean Demountable Design: Tool-free access to rotor and lining – supports manual cleaning, CIP, or WIP protocols for sanitary changeovers.
Housing & Rotor Engineering – PTFE Integrity Meets Heavy Continual Load
The Doebritz PTFE star discharge valve starts with a SUS316L stainless steel housing (or optional carbon steel substrate) that is sandblasted, primed, and then coated with 4–6 mm industrial-grade PTFE via high-adhesion sintering. The rotor is precision-machined from solid 316L, then fully encapsulated in PTFE – no exposed metal edges. Shaft sealing employs lip seals with air purge chambers (optional PTFE packing) to prevent fine powder migration. All flanges are HG20592 or custom DIN/ANSI, drilled after lining to ensure perfect mating. External surfaces receive epoxy coating or stainless steel bright finish with anti-fingerprint treatment, while internal Ra ≤ 0.8 μm (under PTFE) for non-stick performance.
Technical Specifications – Doebritz PTFE Star Discharge Valve (Model DBR-1237 Platform)
Body Material: SUS316L with full PTFE lining (also available: carbon steel + PTFE, or PTFE/PE/PA for non-metallic zones)
Rotor Type: 8-vane open rotor, PTFE encapsulated
Radial Clearance: 0.1–0.2 mm (CNC matched)
Shaft Seals: PTFE lip seals + air purge (optional PTFE packing)
Pressure Range: -1 bar to +1 bar (vacuum to positive), high-pressure version up to 1.6 bar
Temperature Range: -15°C to +80°C (PTFE lining), optional water-cooled jacket for higher temps
ATEX Certification: Zone 20/21/22, II 1/2 D c, pressure shock resistant 16 bar
Port Sizes: DN150, DN200, DN250, DN300, DN350 (customizable)
Drive Options: Direct gearmotor, VFD-ready, explosion-proof motor (Ex d)
Finish (product contact): PTFE glossy smooth, Ra ≤ 0.8 μm
Cleanability: Quick-release disassembly for manual cleaning; optional CIP/WIP ports
| Specification | Parameter |
|---|---|
| Model Base | DBR-1237 Platform |
| Body Substrate | SUS316L / Carbon Steel + PTFE Lining (4–6 mm) |
| Rotor Type | 8-Vane Open Rotor, PTFE Encapsulated |
| Radial Clearance | 0.1–0.2 mm (CNC matched) |
| Max Differential Pressure | 1.0 bar standard, up to 1.6 bar HD |
| Air Leakage @ 0.6 bar | < 0.2 m³/h |
| Temperature Range (Product) | -15°C to +80°C (PTFE), up to 150°C with cooling |
| ATEX Certification | Zone 20/21/22, II 1/2 D c, 16 bar shock |
| Flange Standards | HG20592, DIN, ANSI, JIS (custom) |
| Surface Roughness (Wetted) | Ra ≤ 0.8 μm (under PTFE) |
| Cleanability | Quick-release, manual/CIP/WIP |
| Motor Options | IEC frame, VFD-ready, Ex d explosion-proof |
Heavy-Duty Application Scenarios – Where PTFE Star Discharge Valve Excels
Corrosive Powder Pneumatic Conveying
Fluoropolymer powders, lithium battery salts, agricultural intermediates, and chlorinated paraffin – the PTFE lining prevents corrosion and eliminates product adhesion, while the precision clearance ensures stable lock-up under both positive and negative pressure.
Silo Discharging in Chemical & Pharmaceutical Plants
When gravity-dropping aggressive pigments, vitamin intermediates, or acid-functionalized resins, the PTFE star discharge valve provides no leakage, no powder jamming, and supports VFD speed control for batch metering or continuous feeding.
ATEX Dust Explosion Hazard Zones
Certified for Zone 20 (continuous dust cloud) environments, this valve is used in spray dryers, mills, and dust collectors handling combustible organic powders or metal dusts. The anti-static PTFE grade (surface resistivity < 10^9 Ω) prevents electrostatic ignition.
Global OEM Assurance – Doebritz Manufacturing Power
Doebritz operates a ISO 9001:2025 certified factory with in-house CNC machining centers, robotic PTFE coating lines, and full ATEX test benches. Every PTFE star discharge valve undergoes:
– Leakage testing at 0.8 bar differential (max 0.2 m³/h air loss)
– PTFE thickness verification (eddy current)
– Spark test for pin-hole-free lining
– Material certificates EN 10204 3.1
– CE + TÜV + Statement certification
Lead times: standard sizes 2–3 weeks; custom flanges or special PTFE grades 4–5 weeks. Global spare parts availability for 10+ years.
Frequently Asked Questions – B2B Procurement
- Q: Can the PTFE star discharge valve handle 120°C corrosive gases?
- A: Standard PTFE lining is rated for continuous operation up to 80°C (product temperature). For higher temperatures up to 150°C, specify the optional PFA lining or water-cooled jacket design. Doebritz provides thermal expansion compensation in the housing.
- Q: How does the PTFE lining affect volumetric efficiency compared to bare stainless steel?
- A: The PTFE thickness (approx. 0.5–1.0 mm per side) reduces theoretical displacement by 70% for free-flowing powders), often outperforming metal rotors that suffer from material build-up.
- Q: Is the valve suitable for FDA-compliant food contact?
- A: Yes. Doebritz offers FDA-grade PTFE (21 CFR 177.1550) and polished 316L substrate. The quick-release design supports CIP cleaning, making it suitable for dairy powder, spice blends, and nutritional ingredients requiring < 10W/30W cleanroom compliance.
- Q: What is the recommended maintenance interval for the shaft seals?
- A: With air purge (0.2–0.5 bar above conveying pressure), PTFE lip seals typically last 8,000–12,000 operating hours. For highly abrasive fine powders, upgrade to PTFE braided packing for extended life. Doebritz provides seal kits and 24/7 technical support.
- Q: Can I get a custom flange pattern (e.g., ANSI 150#, JIS 10K) and motor voltage for a project in Southeast Asia?
- A: Absolutely. Doebritz specializes in OEM and project-specific configurations – any flange standard, any motor voltage (230/460V, 380V, 400V, 50/60Hz), and any explosion-proof class. Request a factory quote with your dimensional drawing.
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