Sludge Dryer Feed Screw Conveyor

Product Overview

The WLS420×8500 sludge dryer feed screw conveyor is a shaftless screw conveyor (WLS series) purpose-built as the feed stage of sludge drying lines. It receives dewatered sludge from filter equipment and delivers it continuously at a controlled rate into the inlet of a low-temperature sludge dryer. Installed at a -20° downward incline, the unit moves material downward under both gravity and screw thrust, forming a steady feed stream that prevents wet cake build-up and bridging at the dryer entry.

Wetted parts are selected for sludge duty: the trough and cover are 304 stainless steel, the spiral is manganese steel, and the trough is lined with a 10 mm UHMWPE liner, combining corrosion resistance, abrasion resistance, and low friction. The shaftless design suits high-moisture, fiber-laden sludge and is a typical configuration for dryer feed applications.

Technical Specifications

Construction and Design Highlights

Downhill Feed Arrangement

The -20° incline lets the spiral push material downward against gravity, creating a fixed elevation difference between inlet and outlet. The unit connects directly to the dryer inlet, avoiding cake build-up and compaction at the feed point.

304 Stainless Steel Trough and Cover

The trough uses 4 mm plate and the cover 2 mm plate, both 304 stainless steel for corrosion resistance in sludge environments. One φ450 mm outlet is on the trough side and one φ450 mm inlet on the cover side; both can be matched to the dryer inlet flange.

Manganese Steel Spiral

With a φ420 mm outer diameter, 350 mm pitch, and a 20 × 160 mm blade section, the manganese steel spiral delivers better wear resistance than carbon steel for sand-laden filter cake. The shaftless design advances fibrous and hair-like material without wrapping, a key requirement in dryer feed duty.

UHMWPE Trough Liner

A 10 mm ultra-high molecular weight polyethylene liner provides a low-friction, self-lubricating surface, reducing wear on both the spiral and the trough. The liner is a replaceable wear component, keeping the major overhaul interval practical in abrasive service.

Working Principle

The shaftless spiral is driven only at one end and rotates inside a U-shaped trough, advancing material continuously along the full blade length. With the -20° downhill arrangement, the gravity component acts in the same direction as screw thrust. The 8 m³/h figure is the design capacity; actual throughput varies with sludge moisture content and viscosity.

Applications

• Low-temperature sludge drying: receives filter cake from belt or plate-and-frame filter presses and feeds the dryer at a controlled rate
• Feed stage of sludge incineration and cement kiln co-processing lines
• Downhill metered conveying of other sticky, fiber-laden materials

Sizing and Maintenance Notes

Spiral diameter, length, incline angle, and inlet/outlet positions can be customized to the dryer feed elevation and site layout. During operation, monitor residual UHMWPE liner thickness and spiral blade edge wear regularly — sand-laden material accelerates wear.