Weir : Enhancing the flexibility of your process pipeline

A key component of any mill circuit process is flexibility. The more freedom the pipeline has to move, the less energy is required, resulting in a faster and leaner production, with less risk of breakdown.

Take the human body for example. The older we get, the stiffer our muscles become affecting our range of movement around our joints. The same can be said for a pipeline system: the pipes require flexibility to move!

An integral part of everyday mining, the added flexibility and increased wear performance achieved using hoses make them a product of choice for many operators.

Flexible hose solutions have been used throughout mineral processing for many years and its advantages are well known. Installing a combination of straight hoses, preformed bends, intake and discharge hose reducers, slurry bellows or a custom designed hose solution into a piping circuit provides multiple advantages to the overall flexibility of plant design and maintenance. For the purpose of this feature, I would like to focus explicitly on pre-formed hose bends and how these can benefit your process.

Pre-formed hose bends

Although it's important to take a holistic approach to improve a process circuit in its entirety, there are individual brush strokes of specific importance in delivering the overall advantage of a flexible pipeline. A key component of any flexible pipeline is pre-formed hose bends which complement the entire circuit.

Pre-formed hose bends may seem like a small consideration on the grand scale of a mine site, yet the advantages they yield are significant.

The advantages of pre-formed hose bends

• Ergonomically easy to install, creating a flexible union with the pipeline or pipe spool
• Cost saving as a result of quick and easy installation
• Improved wear performance
• Absorbs vibration
• Custom-made to match operators' internal diameter, bend angle, radii and centre line to face requirements
• Manufactured to suit a wide range of duties

Wear and corrosion repair in a process pipeline

Every day a mine site pumps large amounts of slurry through its pipelines. This slurry is often highly abrasive and corrosive; creating a great deal of strain and wear on the pipeline.

Maintaining critical assets like slurry pipelines against wear and corrosion is an important consideration for maintenance teams. So how do pre-formed hose bends differ from steel lined pipe bends?

Steel lined pipe bends are rigid, giving the plant operators little flexibility to manoeuvre and install replacement pipes, which can result in hours of lost downtime. The lack of flexibility creates ergonomic issues on fitment and often chain blocks are needed to pull the rigid bends into place, which in turn loads up other critical equipment and pipework.

Exposure to the natural elements also impacts on pipework, resulting in contraction and elongation of the pipework due to temperature fluctuations. Temperature, ground movements due to natural causes, or pressure surges can potentially load up equipment due to the lack of flexibility in a pipeline and this will have a negative impact to the structure of the pipeline and the adjoining assets.

By incorporating preformed hose bends in the pipe circuit, you give the structure freedom to move as required by multiple external factors and slurry requirements. Implementing flexibility into the pipeline aids deflection, avoiding stresses onto the frame and helps with misalignment. The goal is to distribute interior wear evenly.

Misalignment in the slurry flow

To successfully match internal diameters between steel lined bends and the adjoining pipework, the wear lining thickness should often be consistent throughout all mating pipework. This makes it difficult to address the high wear areas that are commonly experienced in steel lined bends as increasing the rubber thickness creates a misalignment, which can then lead to a reduction in slurry flow and increased velocity and wear. This could then potentially lead to abrasion on the leading edge and result in delamination of the internal wear liner.

This is not the case with Linatex® preformed hose bends, as our product is engineered to suit the required internal diameter, and as a ply up manufacturing process we are able to increase the lining thickness within the bend and match the same internal diameter as the adjoining pipework. In fact, we can build up the outer arch, where we see the most abrasion, with additional lining thickness to increase the life of the preformed Linatex® hose bend without impacting on the internal diameter or flow of slurry through the bend.

Wear materials

In a steel pipeline, the mineral particles impact against the rubber lining and the rubber absorbs the kinetic energy and deflects the particles. As the particles continue to abrade the rubber it wears to a minimal thickness where the compound is unable to absorb the impact of the mineral particles. This results in either the adhesive bond between the rubber and steel failing and the rubber delaminating, or the rubber holing out.

In contrast, the same Linatex® rubber compound used in a Linatex® 808-PHB preformed hose bend will outperform a lined steel pipe using the same compound. The critical difference is the matrix of the bend, manufactured with raw materials such as nylon or polyester and incorporating a steel wire helix, as the construction allows for impact from the process slurry to dissipate through the bend. The rubber preformed hose bend absorbs energy far more effectively than a rigid steel bend, increasing the wear performance of the hose bend and improving the service life of the entire pipeline.

When it comes to pipelines, we live by the motto: 'The more movement, the less wear' - and this is achieved by the materials we use.

Wear liner composition is critical to the performance of pre-formed hose bends. Our premium Linatex® natural rubber suits most slurry duties and is designed to prolong wear performance of the pipeline by providing outstanding wear resistance and extended wear life. Where Linatex® rubber is not suitable for the required duty, we also offer a broad range of alternative compounds such as Linagard® and Linard® polymers. These natural rubber products provide high resilience and resistance to wear for aggressive chemical applications.

Within the ever-changing minerals marketplace, it's important that we design our products and solutions for your specific duty parameters to yield the greatest efficiency in your processing environment. We custom build our Linatex® hose systems to suit your operational needs, and complement our overall pipeline solutions offering.