Vertical Screw Mixer, Doebritz Industrial Mixer, 150 Tons/Hour / ATEX Zone 21

Product Summary

Engineered for continuous high-volume blending of dry powders, granules, and fibrous materials, the Doebritz Vertical Screw Mixer delivers a homogeneous output of up to 150 tons per hour. Featuring a heavy-duty ATEX Zone 21 certified housing and a low-friction auger flighting design, this vertical agitator guarantees minimal residual material (<0.5% dead zone), making it the preferred choice for chemical, mineral, and food processing lines requiring 24/7 reliability.

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Why Source Doebritz Vertical Screw Mixers

As a certified ISO 9001:2025 manufacturer with 15+ years of OEM supply to Fortune 500 cement and pigment plants, Doebritz provides procurement advantages that lower total cost of ownership (TCO).

• CNC-Precision Flighting: Each screw helix is 5-axis machined to <0.1mm clearance, eliminating product trapping and reducing cross-contamination risks.
• Minimal Dead Zone: Vertical cone geometry with a steep 75° angle promotes mass flow, ensuring <0.5% material retention during batch changeovers.
• ATEX & Dust Explosion Proof: Standard configuration includes ATEX Zone 21 / 22 certification for explosive dust atmospheres (optional Zone 0).
• Heavy-Duty Outboard Bearings: Isolated bearing housing prevents dust ingress, doubling service life in abrasive environments (e.g., silica sand, carbon black).
• Global OEM Logistics: Ready stock of screw tips, stuffing boxes, and drive spindles in EU, US, and Asia hubs. 15-day lead time for non-standard flange sizes.

Housing & Rotor Engineering

The Doebritz Vertical Screw Mixer begins with a cast ductile iron GGG-40 or SS316L conical housing, internally polished to a Ra 1.6μm finish for non-stick performance. The screw assembly features a helical auger flight with a variable pitch – compact at the intake for shearing agglomerates, expanding towards discharge for gentle blending. Welded by robotic submerged arc for maximum fatigue strength, each rotor is dynamically balanced at 150% operational speed. For high-abrasion duties, optional CrC (Chromium Carbide) hardfacing or PU-coated flights are available.

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Technical Specifications

Below are the standard engineering boundaries for the Doebritz VSM series. Customizations (flange drilling, increased shaft diameter, sanitary finish) are supported for OEM clients.

Specification	Detail
Model Range	VSM-200 (200L) to VSM-5000 (5000L)
Body Material	Cast Ductile Iron GGG-40 / SS316L (Sanitary)
Screw Design	Variable pitch helical auger, 6 to 12 mm flight thickness
Drive Power	5.5 kW to 110 kW (IE4 motor standard)
Capacity (Dry Powder)	10 to 150 tons/hour (depending on screw speed & bulk density)
Max Operating Temp	80°C standard / 300°C with cooling jacket
ATEX Rating	ATEX Zone 21 (II 2D Ex h IIIC Db) / Option Zone 0
Surface Finish	Ra 1.6μm to 3.2μm (Ra 0.8μm optional for food/pharma)

Heavy-Duty Application Scenarios

Pneumatic Conveying Systems Integration

When mounted beneath a dense-phase or lean-phase transporter, the Doebritz Vertical Screw Mixer works as a live bottom feeder, preventing bridging and providing a steady, pulsed mass flow to rotary valves. The vertical design suppresses pressure pulsation feedback into the silo.

Silo Discharging & Blending

For large storage silos holding fly ash, lime, or plastic regrind, the unit acts as a recirculation mixer – extracting material from the outlet and returning a homogenized stream to the top, effectively eliminating vertical segregation during storage.

Dust Filter Collectors

In dedusting systems, the vertical screw functions as a dust conditioner, mixing fine captured dust with binding agents (water or oil) to create dust-free pellets before disposal, compliant with EPA fugitive emission standards.

Frequently Asked Questions

Q1: What is the typical air leakage rate for a Doebritz Vertical Screw Mixer when used under a pressure system?

A: Standard units maintain 0.25 m³/min at 0.6 bar differential pressure when tested with nitrogen. For higher pressure sealing (up to 2.5 bar), we offer a pressurized stuffing box or mechanical seal option, reducing leakage below 0.05 m³/min.

Q2: Can Doebritz provide non-standard inlet/outlet flanges, e.g., DIN, JIS, or ASME?

A: Absolutely. While standard is ANSI 150# or PN10, we supply customized drilling patterns and facing finishes per ASME B16.5, DIN 2576, or JIS B2220. Minimum order quantity for custom flanges: 4 units.

Q3: Is the vertical screw mixer ATEX certified for gas groups IIC and dust zones?

A: Yes. Doebritz offers full ATEX II 2D Ex h IIIC Db (dust) and II 2G Ex h IIC Gb (gas) certification. Each unit includes a laminated nameplate with CE and identifying certificate number. IECEx is also available upon request.

Q4: What’s the maximum operating temperature for the VSM series?

A: Standard packing seals support 80°C continuous. With the high-temperature configuration (graphite packing and a cooling jacket on the lower bearing), the mixer handles up to 300°C product temperature.

Q5: Do you offer a trial rental unit before bulk procurement?

A: For qualified industrial accounts, Doebritz provides a 160 L capacity pilot mixer (VSM-200) for on-site material testing. Rental fee is credited back to the first purchase order of 10+ units.