600-15000 DWT 100-500t/h Fixed Screw Ship Unloader

Continuous Discharge for Dedicated Berths

The ATXL-A is installed on a reinforced concrete foundation at the quay edge. Its rotary tower slews the horizontal beam while the vertical screw arm swings in and out, so the feeder tracks the material surface in three dimensions and keeps the screw intake buried in the cargo. Material is lifted by the vertical screw, transferred to the horizontal screw and discharged to the shore conveyor through the discharge device.

Because the base is fixed, there are no rail bogies or travel drives. That configuration suits terminals with predictable vessel arrivals and a single assigned berth, and it lowers the initial capital outlay compared with a rail-mounted machine of the same capacity.

Technical Parameters

Where the Fixed Configuration Fits

• Small port terminals — 600–10000 DWT vessels with annual throughput below 800,000 tons.
• Inland river ports — restricted-draft locations handling barges and small coasters.
• Cement distribution hubs — receiving bulk cement from 3000–12000 DWT vessels.
• Grain export facilities — dust-controlled handling of wheat, corn and soybeans.
• Industrial raw material receiving — power plants and factories taking coal, limestone or petcoke.
• Fertilizer terminals — granular and powdered fertilizers with moisture provisions.

Where vessel sizes vary widely or several berths share one machine, our 1000-70000 DWT 200-1500t/h Rail mobile Screw Ship Unloader covers a wider vessel range with rail travel.

Materials and Operating Boundaries

Sticky or cohesive cargoes may need reduced feed rates. For high-moisture materials above 12%, optional screw liners with reduced clearance are available.

Screw, Drive and Dust Control

The screw conveyor is the core of the machine. Standard screw diameter runs 350–500 mm with a pitch-to-diameter ratio of 0.7 and a speed range of 50–160 RPM through a variable frequency drive, allowing flow modulation from 20% to 100% of rated capacity. For abrasive cargoes such as quartz-bearing materials, we offer hardfaced flighting at 550–600 Brinell or bolt-on wear segments.

Dust capture operates at three points: the screw intake shroud, the transfer chute between the vertical and horizontal arms, and the discharge hopper. A central pulse-jet baghouse maintains negative pressure throughout, with filter bag efficiency of 99.9% for particles larger than 1 micron. Automatic cleaning cycles activate when differential pressure exceeds 1000 pascals.

Installation, Utilities and Controls

• Foundation — concrete pad 5.5 m × 5.5 m minimum, 1.8–2.2 m deep depending on soil bearing capacity; 35 tonnes load per support leg; anchor bolt pattern supplied with engineering drawings.
• Power supply — 380–690 V, 50 Hz or 60 Hz, three-phase; installed motor power 160–250 kW by capacity selection; terminal box at pedestal base; optional generator connection.
• Control — local control panel with remote monitoring capability; PLC-based sequencing of slew, luff, swing and screw speed; fault alarm and safety interlocks.
• Protection — integrated lightning protection system.

We configure the control system around the required line interface, so the unloader can hand over to the shore conveyor, silo feed or receiving hopper without manual intervention at the transfer point.

Quality, Testing and Acceptance

AOTUO is the responsible drafting unit for industry standard JC/T 2575 “Bulk Cement Spiral Unloader” and holds more than 100 valid patents and software copyrights. Production takes place in a 14,000 m² A-level workshop with testing equipment, under quality, environmental and occupational health and safety management systems.

Emission testing follows ISO 9096:2017 for stationary source emissions, sampled at 100% nameplate capacity over a three-hour continuous period, with third-party validation reports available. We recommend compliance testing every 12 months after handover.

Maintenance and Serviceability

• Screw flighting thickness inspection every 400 operating hours.
• Liner plate wear assessment at 800-hour intervals.
• For cement, screw flight replacement typically between 3500 and 5000 hours depending on abrasiveness.
• The vertical screw assembly includes a hinged access door for inspection without full screw extraction.
• Operator certification requires 32 hours of training covering boom controls, emergency stop procedures, dust system monitoring and daily inspection; refresher training every 24 months.

Information We Use to Configure Your Solution

• Vessel deadweight range and typical hatch geometry, including hatch width and hold depth.
• Material type, bulk density, particle size distribution, moisture content and angle of repose.
• Required peak and average discharge rate, and annual throughput target.
• Quay layout, freeboard range, reach from quay edge and foundation soil data.
• Shore receiving interface: conveyor, hopper or silo, and required transfer height.
• Available power supply, voltage, frequency and any generator operation.
• Local emission, noise and safety requirements applicable to the berth.

Our proposal is based on the working point, material and production target. Where a project also needs loading or transfer equipment, we supply the dust collector, belt conveyor and air slide range as part of the same port transfer system.

Frequently Asked Questions

How does fixed installation affect operational flexibility?

The fixed unloader serves a single dedicated berth. For terminals with predictable vessel arrivals and consistent vessel sizes, this configuration delivers adequate coverage without the cost of rail bogies and travel drives. Vessel positioning is managed through mooring line adjustments within the ±135° slewing coverage and a reach of approximately 15 m from the quay edge.

What is the recommended screw maintenance schedule?

Inspect screw flighting thickness every 400 operating hours and assess liner plate wear at 800-hour intervals. In cement service, screw flight replacement is typically required between 3500 and 5000 hours depending on material abrasiveness. The vertical screw assembly has a hinged access door so inspection does not require full screw extraction.

How does the dust collection system achieve 10 mg/m³?

Three-stage capture at the screw intake shroud, the transfer chute and the discharge hopper feeds a central pulse-jet baghouse that holds negative pressure through the material path. Filter bags reach 99.9% efficiency for particles above 1 micron, and automatic cleaning cycles start when differential pressure exceeds 1000 pascals.

Can this unloader handle different material types?

The standard configuration handles bulk density from 0.6 to 1.8 t/m³, particle size up to 40 mm and moisture up to 10%. Changing material requires cleaning the screw housing and dust collection system. Optional reduced-clearance screw liners suit high-moisture materials above 12%.

What is the capacity calculation basis?

Rated values are derived from cement at 1.2 t/m³ in free-flowing condition with moisture below 5%. Actual throughput varies with angle of repose, moisture level, particle size distribution and hold geometry; reduction factors apply for materials with an angle of repose above 40°.

Which screw configuration options are available?

Standard screw diameter is 350–500 mm with a 0.7 pitch-to-diameter ratio and 50–160 RPM via variable frequency drive. Abrasion-resistant options include hardfaced flighting at 550–600 Brinell or bolt-on wear segments for quartz-bearing materials.