System solution pays off in hydraulics design

Hydraulic control equipment, hydraulic motors and high efficiency planetary gear stages all feature in a new self-propelled sand and gravel sorter designed for quarrying and grading operations.

A new type of self-propelled sand and gravel sorter designed for quarrying and grading operations by Rotamill of Rotherham is being powered by a combination of hydraulic control equipment, hydraulic motors and high efficiency planetary gear stages from Brevini UK.

The combination system provides reliable and efficient high-torque, low-speed operation to both the track drives and conveyor system The machine replaces traditional static hoppers that require an additional tractor unit to drag them from one position in the quarry to another in order to feed the main field conveyor, which carries the sand and gravel from the face to the process plant.

The advantages are inevitably increased production through shorter handling time and quicker redeployment to new positions for working.

There is also a long term saving in not having to purchase and maintain an additional dedicated tractor unit.

The complete system was designed and supplied from the UK.

Jon Snaith, Sales Manager for Brevini UK comments: "The design aim was to optimise the effectiveness and efficiency of the package as a whole, contributing to the reliability and competitiveness of the machine".

The package included a hydraulic pump to provide system pressure; the pump was the first of several items supplied by Brevini UK group company Sam Hydraulik that also supplied the proportional valves for the hydraulic circuit controlled by the radio unit.

The design brief for the new track mounted heavy duty "box feeder" was to design and manufacture a machine that was capable of handling 150t/h of sand and gravel of up to 100mm in size.

The hopper has a reject grid fitted that performs primary sizing - anything above the mesh size is rejected and rolls off on to the floor, The machine had to be self-propelled to allow ease of movement from one position to another and have a travel speed of approximately 2.5km/h in both forward and reverse under full load conditions.

The weight of the box feeder machine is around 15,000kg and it can carry a further 12,000kg of product.

Power is provided by a Cummins four-cylinder diesel power plant delivering an output power of 100hp to a hydraulic power pack.

Most tracked vehicles from tanks to cranes use hydraulic power for the tracks as it allows very high torque operation and is conveniently packaged in compact independent power units for each driven wheel or sprocket.

The tracks on the Rota-Mill unit are fitted with salt chains, minimising the risk of seizure when stood for long periods of time.

They are driven by Brevini case-rotating track drive gearboxes and hydraulic motors, the planetary gear component provides an additional gearing down stage, providing more low speed torque and allowing for a smaller and therefore more hydraulically efficient motor to be used.

The main belt conveyor has a variable speed feature and is also driven by a Brevini shaft mounted planetary gearbox and an orbital hydraulic motor from Brevini Group company Sam Hydraulik.

The combination of a small hydraulic motor and multiple stage planetary gearing also provides efficient low speed torque and high reliability.

The drive combination is tough and weatherproof, as it has to be, to survive outside in a quarry environment.

The system requires minimal maintenance and is well proven in arduous conditions on land and at sea.

The machine is operated remotely by a radio control unit and proportional valves in an onboard hydraulic control circuit designed and supplied by Brevini.

Hydraulically operated skirts fitted to each side of the machine are used to protect the tracks from damage caused by the wheels of the loading shovels and from any spillage of product.

The skirts lift easily to provide access for inspection and maintenance of the tracks.

Initial trials have indicated that the machine is capable of safely handling much more than the target 150t/h.

Brevini UK drew on its integrated hydraulic systems and gearbox expertise to engineer a complete drive system for the track mounted heavy duty box feeder, using components from group companies and in-house design expertise to deliver a power transmission system solution.

Bob Taylor, Managing Director of Rotamill, confirms: " Previously I've encountered compatibility and servicing problems with components sourced from multiple suppliers".

"It is essential that the hydraulics on our machines are able to cope with harsh operating and environmental conditions".

"We demand technical support in the event of any problems, rather than suppliers blaming the failure on a different component and avoiding any responsibility".

"Brevini UK were the only supplier who could do this for us: design, specify, supply and support the complete system solution".

Jon Snaith adds: "In our experience, machine manufacturers are more and more reliant on suppliers who have good quality products, coupled with the knowledge and experience to take responsibility for the performance of the machine".

"Rotamill is a classic example where meeting the client's engineering, supply and support requirements are paramount".

Back to top