Worm Gearbox for Screw Conveyor / Auger

Worm Gearbox for Screw Conveyor / Auger — Reliable Bulk Material Drive

Screw conveyors and augers are the workhorses of mineral processing, grain handling, cement plants, and waste-management facilities. A compact worm gearbox mounted directly to the trough end-plate drives the screw at precisely controlled low speeds while handling the high resistive torques generated by dense, abrasive, or sticky bulk materials. Visit our applications page to explore the full range of worm reducer use cases.

Application Detail: Screw Conveyors in Mining & Processing

In mining applications, screw conveyors transport ore fines, tailings, and filter cake at controlled feed rates. The worm gear reducer provides the necessary speed reduction from a standard 1,450 rpm motor to typical screw speeds of 20–120 rpm, while generating the high starting torque needed to shear through packed material. The hollow-shaft (torque-arm) mounting option — where the gearbox slides directly onto the conveyor screw shaft — eliminates the need for a separate coupling, shaft alignment, and mounting frame, reducing installation time significantly.

Construction Details

Housing: Heavy-duty cast-iron body with high-grade sealing — prevents fine ore dust and moisture from contaminating the gear oil.
Worm Wheel: Tin-bronze (ZCuSn10Pb1) — provides the lubricity needed for the high contact stresses in slow-speed, high-torque operation.
Seals: Special heavy-duty oil seals rated IP65+ — resists fine dust ingress characteristic of mineral processing environments.
Output Options: Solid shaft, hollow bore (torque-arm), or flanged output for direct trough mounting.

Technical Parameters

Parameter	Value / Range
Gear Ratio	7.5:1 – 100:1
Output Torque	Up to 3,200 Nm (standard series)
Input Speed	1,450 rpm (50 Hz, 4-pole)
Typical Screw Speed	15 – 120 rpm
Housing Material	Grey cast iron GG25 / Nodular cast iron GGG50
Mounting	Foot-mount, hollow shaft torque-arm, flange mount
Protection	IP55 standard; IP65 with heavy-duty seals
Thermal Rating	S1 continuous duty; S2/S3 for intermittent loading

Service Factor Note: Screw conveyors handling wet, sticky, or over-sized material should use a service factor of 2.0–2.5. If the screw is started under full load (choked condition), an additional start-up torque allowance of 2× rated torque for up to 2 seconds should be confirmed against the gearbox peak-torque rating.

Standards & Certifications

Worm gear units for screw conveyors conform to ISO 9001:2015 quality management and carry CE marking. Input flanges comply with IEC 60072 motor-frame dimensions, covering B3, B5, and B14 mounting types for compatibility with all standard three-phase and single-phase motors. Dust protection IP65 is standard; IP66 is available for wash-down environments in mineral processing plants.

Real-World Case Studies

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Gold Processing Plant — Northern Territory — Tailings screw conveyor

Challenge: Standard gearboxes failed within 4 months due to ultra-fine gold tailings penetrating seals.

Solution: Fitted cast-iron worm reducers with IP65 heavy-duty triple-lip seals and quarterly oil analysis program.

Result: MTBF increased from 4 months to 26 months; annual replacement costs down 78%.

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Cement Plant — South Australia — Raw meal screw feeder

Challenge: Gearboxes ran excessively hot (>90°C oil temperature) during summer at 42°C ambient.

Solution: Switched to synthetic ISO VG 220 oil and added external cooling fins; thermal derating applied during design.

Result: Oil temperature stabilised at 72°C maximum; no heat-related failures in two production seasons.

Grain Terminal — Fremantle, WA — Ship-loader auger conveyor

Challenge: High starting torque when auger engaged compacted grain caused motor tripping and coupling shear.

Solution: Selected worm reducer with ratio 50:1 and peak-torque rating 2.5× rated load; hollow-shaft mount eliminated coupling.

Result: Zero coupling failures; auger starts reliably under full load with motor protection intact.

Why Partner with Us?

Hollow-Shaft Expertise

Torque-arm hollow-shaft models eliminate coupling alignment — reduce installation time by up to 60%.

Custom Auger Interfaces

Non-standard bore diameters and keyway profiles machined to your screw-shaft drawings.

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Thermal Engineering

Thermal capacity calculations provided for high-ambient and enclosed installations at no charge.

Export Packaging

Sea-freight rated crating and corrosion-protection packaging for remote mining sites.

Full Documentation

Test certificates, material certs, and dimensional drawings supplied with every order.

Frequently Asked Questions

▼ What is the advantage of a hollow-shaft worm gearbox for screw conveyors?

A hollow-shaft (torque-arm) gearbox slides directly onto the screw shaft and is prevented from rotating by a torque arm bolted to the trough structure. This eliminates a flexible coupling, separate mounting frame, and alignment procedure — reducing installation time and removing the coupling as a failure point.

▼ How do I select the right gear ratio for my screw conveyor?

Divide your motor’s rated speed (e.g., 1,450 rpm) by the required screw speed. For example, 1,450 ÷ 40 rpm = 36:1 ratio. Round up to the nearest available catalogue ratio (e.g., 40:1). Then verify that the resulting output torque does not exceed the gearbox’s rated output torque at that ratio.

▼ Can the gearbox handle a screw that starts against a full load?

Yes, provided the gearbox’s peak-torque rating (typically 2.5–3.0× rated torque) exceeds the start-up breakaway torque of the loaded screw. If the start-up torque is unknown, measure it with a torque meter or calculate it from the screw’s material-resistance coefficient and conveyor geometry.

▼ What causes early seal failure on screw conveyor gearboxes?

The most common cause is excessive radial load on the output shaft due to an off-centre screw or worn trough end-bearing. This distorts the output shaft seal lip, accelerating wear. Ensure the conveyor’s end bearing is properly maintained and that the hollow-shaft bore is concentric with the screw shaft.

▼ Is IP55 sufficient for a screw conveyor in a mineral processing plant?

For most indoor dry-material applications, IP55 is adequate. For outdoor installations, wash-down zones, or very fine-dust environments (sub-100 µm particles), specify IP65 or IP66 to ensure long-term sealing performance.