Receival, Storage and Outloading

Sliding-Frame Silos and Bunkers

SPIRAC’s sliding-frame silo systems complement our spiral conveyor live bottom expertise and expand our experience and competence in offering sludge storage solutions in the water and wastewater industries as well as various industrial applications.

What is a sliding-frame outloading System?

A sliding-frame is an extremely efficient extraction system that allows non-free flowing materials to be discharged from a flat bottom silo or receival bunker. These bulk materials can easily block the bottom of a silo by forming a bridge of material. The action of the hydraulically driven sliding frame breaks any bridges that may form over the extraction screw and pushes/pulls the material toward the centre of the silo for discharge.

Round silos – The sliding-frame is built as an elliptical frame, made of solid steel bars profiled to a wedge shape. This elliptical framework with its wedge profile, pushes under the sludge in one direction and draws it toward the discharge opening in the other, thereby allowing near total emptying of a flat bottom silo.

Rectangular silos – the sliding-frame is constructed as a rectangular “ladder” shape, transferring material from one wedge shaped “step” of the “ladder” to the next as it oscillates back and forth. This design is suitable for steel or concrete silos or bunkers.

PRODUCT BENEFITS

Reliable and simple operation.
Can be applied to rectangular silos, concrete bunkers and truck receival bunkers.
Even load distribution along full the length of the silo / hopper.
Minimal ongoing maintenance over the life of the equipment.
Complete aftermarket support available.
Prevents material bridging
Efficient handling of sticky or fibrous inconsistent materials.
High capacity outloading rates.
Low power consumption.
Low maintenance, no service parts inside of silo.
Modular system reduces site installation time.
Flat bottom silos are economical to manufacture.
Flat bottom silos maximize storage capacity for a given footprint and height.

TECHNICAL DETAILS

Round and rectangular sliding-frame outloading capacity up to 250m³/h (325yd³/h). High out loading rates via multiple shaftless screws, which are manufactured from very durable & abrasion resistant; high tensile micro-alloy steel.
Available in varying geometries and storage capacities ranging from 20m³ to 1000m³. (26yd³ to 1300yd³)
Allows for vertical walls and cylindrical silo construction, optimizing volume utilization with the capability of reducing height or footprint.
Round Sliding Frame Silos and Bunkers
- Diameter 3 -10m (10-30ft)
- Height 3 -15m (9 -50ft)
Rectangular Sliding Frame Silos and Bunkers
- Height 3-15m (9-50ft)

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Sliding Frame Installation

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Why Should You Buy From SPIRAC?

SPIRAC is a trusted global leader in engineered wastewater solutions for materials handling, delivering reliable, purpose-built systems backed by decades of expertise. Customers choose SPIRAC for its ability to design and manufacture high-quality shaftless spiral conveyors, screenings handling systems, and bulk solids handling equipment that perform in the toughest industrial and wastewater environments. With a strong focus on innovation, durability, and low maintenance, SPIRAC solutions are engineered to reduce downtime, improve operational efficiency, and minimise lifecycle costs. Supported by a global footprint and dedicated local service, SPIRAC partners closely with clients to provide customised, end-to-end solutions that consistently deliver long-term value and performance.

What To Expect From SPIRAC?

When you choose SPIRAC, you can expect a reliable partner committed to delivering high-performance, engineered solutions tailored to your specific needs. From the initial consultation through design, manufacturing, and installation, SPIRAC works closely with clients to ensure every system is fit-for-purpose and built to last. You can expect robust equipment designed for harsh operating conditions, minimal maintenance requirements, and long service life. SPIRAC also provides strong technical support, responsive service, and ongoing collaboration to optimise system performance, reduce operational costs, and ensure your materials handling processes run smoothly and efficiently.

Can SPIRAC provide evidence of proven track record?

SPIRAC can confidently demonstrate a proven track record built on decades of global project delivery and industry expertise.

With installations in municipal and industrial facilities across Australia, Europe, the Middle East, the UK, and North America, SPIRAC has successfully delivered thousands of materials handling systems operating in demanding environments such as wastewater treatment plants, pulp and paper mills, food processing facilities, and heavy industry. Its shaftless screw conveyor technology is widely recognised as a benchmark in the industry, with many long-term installations still operating efficiently after years of continuous service. In addition, SPIRAC supports its reputation with documented case studies, repeat clients, and ongoing partnerships with leading engineering firms and utilities—demonstrating consistent performance, reliability, and customer satisfaction across a wide range of applications.

Know Your Costs To Plan Effectively?

At SPIRAC, we understand that accurate cost visibility is critical to successful project planning. That’s why our team is ready to provide detailed, transparent quotations tailored to your specific requirements. Whether you’re upgrading existing infrastructure or planning a new installation, we work closely with you to scope your needs and deliver a clear, competitive proposal. With our engineering expertise and practical industry knowledge, you can move forward with confidence—knowing your solution is both technically sound and commercially aligned. Reach out today and let us help you plan with certainty.

only

56^%

of domestic wastewater is safely treated worldwide, and we aim to help improve this.

we serve clients in

60⁺

countries worldwide

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Sliding-Frame Silos and Bunkers

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Sliding-Frame Silos and Bunkers

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