Pump and rubber lining specialist Weir Minerals Africa product manager for rubber products Ronald Govender tells Engineering News that its recently developed Linatex VS and Linard 60 VS steam cure rubber sheeting, which is manufactured from uncured rubber, will enable safer application, compared with chemical cure rubbers.
Designed specifically for the lining of pipes, as well as platework, the newly developed products have similar properties to the traditional Linatex and Linard 60 sheeting.
Govender explains that the method of lining pipes and equipment with steam-cured rubber sheeting is safer for the applicator.
“When it comes to the application of chemically cured rubber products, the risk exists that the incorrect quantity of reagent may be applied. If an excess is applied, it will penetrate through the rubber and reach the adhesive, which will cause the lining to separate from the substrate. If too little is applied, the product will not cure adequately and will result in premature failure,” he says.
He adds that chemically cured rubber, which is often used for lining pipes and equipment, is also, in effect, a cheap, low-grade material that has a shorter service life.
Govender says that Linatex VS has proven differentiated wear performance properties designed specifically for use in fine slurry appli- cations, where hot bonding is the preferred method of installation.
“Ideally suited for autoclave curing and compression moulding, pipelines, chutes, tank linings and hoses, Linatex VS delivers the lowest cost of ownership in its category of abrasion-resistant uncured rubber products,” says Govender.
Govender highlights that the global rubber industry, between 2010 and 2011, experienced the highest natural rubber price increases since 1972, ranging from 40% to 70%, depending on the grade.
He states that the excessive price increases are being driven by the current global rubber shortage, which has worsened when compared with supply in previous years.
Govender believes that the shortage is being fuelled by a recent rise in global demand for natural rubber across many industries, including the mining sector.
He adds that, although it is possible for the tyre manufacturing sector to convert to synthetic rubber in the midst of the natural rubber shortage and rising prices, the industrial rubber sector cannot afford to do this as the specific properties of natural rubber that provide for the necessary wear life of products and their integrity must be maintained.
He says this is central to Weir Minerals’ ‘total-cost-of-ownership’ approach, with the company reporting that the service life of its products is up to four times longer than those of competing products.
“Synthetic rubber will break down more easily compared with natural rubber in the presence of fine slurries,” says Govender.
“Weir’s strategy and the Linatex products go hand in glove with the recent trend by larger mining groups towards total cost of ownership. They are looking to reduce costs and, with our longer product service life, it is no longer necessary to keep replacing linings at short intervals, which translates into extensive maintenance costs,” he says.
Primarily used for abrasion resistance against fine slurries, thereby maximising equipment service life, Linatex is a 95% natural rubber manufactured using Linatex’s patented liquid-phase manufacturing process, which is an automated, continuous manufacturing process.
The company states that the process was developed more than 80 years ago and still remains the benchmark in rubber lining materials used today.
“We manufacture Linatex at temperatures below 40 ˚C, whereas other rubber products are manu- factured using extremely high temperatures of up to 120 ˚C. This breaks down the rubber’s molecular structure and impacts on the integrity of the rubber,” he says.
He adds that the liquid-phase manufacturing process entails very little mechanical work, which allows for the maximum pure rubber physical properties to be maintained.
At Linatex’s ISO-accredited manufacturing facility, in Malaysia, every sheet is simul- taneously measured at a predetermined number of points to ensure consistency of thickness. Random samples are taken and tested at the facility’s laboratories.
Safety and Innovation
Govender states that Weir Minerals is also currently looking at safer and more efficient methods of cutting the Linatex rubber, and this is aimed at minimising the risk associated with manual cutting and also improving delivery times to market.
He says that, at the main Linatex manufacturing plant, in Kuala Lumpur, continuous investment in rubber processing equipment upgrades over the past four years has ensured the highest product and manufacturing quality.
“We are also looking at developing additional rubber com- pounds to complement our product range and capture a larger market segment,” says Govender.
Other innovative developments include a shift in the manufacturing process of liners.
“Previously, our product was manufactured using a batch process, which we have now changed to a continuous automatic manufacturing process to increase consistency,” Govender states.
Meanwhile, Govender believes that skills development in the rubber industry has been domi- nated by the tyre and plastics industries, with industrial rubber being grouped with either of these industries.
However, certain industrial rubber products do not fit into these industries, which leads to skills shortages in the manu- facturing of specific rubber products.
“A specialist product like rubber hoses does not fit into these sectors and skills training requires different skills sets for such a specialised sector. We worked with the Services Sector Education and Training Autho- rity to develop a training programme for the industrial rubber sector and we have our own training division, which trains our staff and provides training for customers, agents and appli- cators at mine sites,” he says.
Govender stresses the need to actively start training in the industry.
“The basics in rubber processing have not changed that significantly, although safety aspects have improved. The industrial rubber sector can piggyback on the tyre sector with regard to training. We can gain a fair amount of skills because this initiative will offer an overview of the industry,” he explains.
The Weir Group acquired rubber lining specialist Linatex last year.
Govender says that the incorporation of the Linatex abrasion-resistant rubber lining products complements Weir Minerals’ extensive product range, which includes pumps, valves and cyclones, and is also expected to give Weir Minerals greater impetus to grow its market share and further strengthen its aftermarket presence.
He adds that Weir Minerals’ approach is “finding the right solution above all”.
“We have engineers that are capable of identifying which rubber sheet product is suitable for any given application. If we do not have a product to suit the application, we will not recommend another product as a substitute for the purpose of a sale,” he says.