Saturday 23rd Oct, 2021

Different horses for conveyor courses

Conveying materials from one spot to another comes in many shapes and sizes. ABHR speaks with Victor Stiller, General Manager at Kotzur Toowoomba, about how the company provides a range of solutions.

Conveying materials from one spot to another comes in many shapes and sizes. ABHR speaks with Victor Stiller, General Manager at Kotzur Toowoomba, about how the company provides a range of solutions.

There are several different types of conveyor systems available for bulk handlers, each with different capabilities depending on parameters such as the required capacity, material to be conveyed, distance, height, and budget.

On top of that, conveying equipment often relies on specific equipment like valves, slide gates, spouts, and transitions to link everything together.

Victor Stiller, Kotzur Toowoomba General Manager, says it’s a case of different horses for different courses.

“Kotzur’s design team will scope out the project to get the best outcome for the client,” he says.

Kotzur can manufacture a wide range of conveyor systems, including drag conveyors, bucket elevators, screw conveyors, belt conveyors, road hoppers and silo unloaders.

Drag conveyors

Drag conveyors are effectively a chain in a loop with paddles attached, encased in an enclosed trough. The chain is driven by a sprocket on the discharge end of the conveyor. Product is dropped in one end, and the chain ‘drags’ the product along the conveyor and it discharges out the other end.

Stiller says there are a few variants available within two main types, en-masse drag conveyors and high-flight drag conveyors.

“En-masse drag conveyors are typically horizontal or shallow angles. They can carry product many times deeper than the height of the flights and as such are quite an efficient machine,” he says.

“High-flight drag conveyors are better suited to inclines that can be quite steep. They have flights that are at least as high as the required product depth which prevents the product rolling back at steep angles.

“Kotzur manufacture both types of drags in capacities from 10 tonnes per hour (and less) up to 1000 tonnes per hour. Higher conveyor capacities than this can be developed as a bespoke solution.”

The materials used for these conveyors is typically galvanised steel, but they can also be made from stainless or painted steel if required. Chains and flights are often manufactured from different materials as well, depending on the application, as some products can be quite aggressive on plain steel.

En-masse drag conveyors have the benefit of being relatively efficient and due to their fully enclosed nature, keep the elements away from the material and stop dust escaping. They are also relatively gentle on the conveyed material itself, when compared with a screw conveyor. In most applications, a drag conveyor will have low maintenance requirements.

Stiller says another benefit is the fact they can have multiple inlets and outlets, with each outlet controlled by a slide gate.

“Having multiple outlets can pose issues with a drag conveyor if product carries past the desired outlet as it can build-up at the ‘head’ end of the conveyor and cause damage,” he says.

“Kotzur have a specially designed ‘carryover head’ for this application that deals with this by returning any carried over product back around. A typical application for a drag with multiple outlets and one inlet would be across the top of several silos for filling. A similar drag conveyor on the bottom of the same silos would have multiple inlets and one outlet.”

Bucket elevators

Kotzur also designs and manufactures bucket elevators, which are the primary means of conveying product vertically. A belt (or chain in some cases) is looped around two pulleys: one at the ‘head’ or top of the elevator, the other at the ‘tail’, or bottom. The belt has a series of buckets attached to it which carry the product up the elevator over the head pulley and as they go over, they either throw the product out of a discharge chute on a high-speed system or simply tip it out on a low-speed system. The belt and bucket system as well as the pulleys are all contained within a fully enclosed casing.

Stiller says that while the the main principle of a bucket elevator is a relatively simple concept, there are many variations in casing material, bucket shape and material, belt material, size, belt speed, capacity, and height.

“The properties of the material being conveyed, and the desired throughput capacity and height are the main determining factors when determining the specifics of the system,” he says.

“The calculation of belt speed, bucket size and shape, pulley size and other parameters needs to be done very accurately, particularly on a high speed or centrifugal discharge elevator as they are all inter-related and impact on the efficiency of the machine.”

Kotzur design, manufacture, install and maintain bucket elevators from very low capacities up to units that achieve 1500 tonnes per hour in a high duty cycle, 24/7 commercial operation.

Casing materials include galvanised steel, stainless steel, or painted fabricated steel. Buckets can be made from different materials as well including stainless steel, mild steel, nylon or HDPE. There is often a high structural component to the elevators, given their size and height, requiring extensive engineering. There is typically a head platform at the top of the elevator for maintenance purposes and an access system to reach it.

Stiller says all of Kotzur’s equipment is designed and manufactured in Australia.

“While we have ‘standard’ models based primarily on capacity and some other parameters, these standard products are configurable to an extent to give optimum flexibility to the client,” he says.

“These can then be automated to different levels, from a basic ‘manual’ system to a system which allows a single operator to control a large and complex storage facility.”