“In our experience, manufacturers are often faced with difficult decisions when it comes to optimising the performance of their existing infrastructure. Investment in a complete system replacement may not be justifiable, particularly as budgets continue to be stretched.
“Machine modernisation offers a cost-effective alternative that if expertly done can deliver long-term productivity improvements. We always combine the client’s knowledge with our engineering design experience to not only restore equipment, but to increase speed, quality and therefore profitability too. Bespoke engineering design enables manufacturers to significantly expand the lifespan of their investment and to remain competitive in the process.” John Bennett, Director, Bennett Engineering Design Solutions.
Marley Eternit is one of the UK’s leading roof systems manufacturers. Its Branston manufacturing plant in Burton on Trent produces high volumes of concrete tiles on automated production lines. Having been in place some years, Marley Eternit required an upgrade to its granulate recycling system to help eliminate hazards, material spillage and manual handling issues while also improving long-term productivity.
The company’s roof tile production includes a process that requires a specially prepared decorative surface coating (known as granulate), to be applied to the upper face of each tile. Originally its granulate line incorporated a series of screw feeders and a bucket elevator employed to transport and eventually recycle the granulate.
Bennett Engineering Design Solutions was approached in early 2016, after having successfully completed a recent design project for the client, to assist Marley Eternit’s engineers with an important recycling system upgrade.
John Bennett, director, Bennett Engineering Design Solutions, explains: “Marley Eternit’s existing system, although reliable, was difficult to access and maintain; it wasn’t capable of increasing output or dealing well with frequent product changeovers without material wastage – half a tonne of granulate was lost each time.”
Marley Eternit’s head of engineering, Lee Rich, comments: “We believed the project would deliver a broad range of improvements to our existing granulate system - including reduced downtime; the removal of operational hazards by re-locating the machinery itself; material wastage; improved ease of access and a greater materials capacity to help improve long-term productivity.”
Health and Safety: it was difficult to access, operate and maintain the original equipment. The system’s motor and gearbox on the bucket elevator was also over six metres up with insufficient means of access. Spillages of the granulate inevitably contributed to a dusty environment.
Down time: the system tended to block up and could be difficult to adjust.
Changeover: emptying the system was arduous, there were always cross contamination risks when changing products. It also took hours to empty the system and often caused a mess which had to be cleaned up.
Working environment: the system occupied a lot of space, leaked granulate and was noisy.
Production rates: although the original equipment had sufficient throughput for normal operations, it did not have sufficient internal storage to allow the production line to keep operating while the granulate supply intermediate bulk unit was changed.
The team at Bennett Engineering Design Solutions surveyed the existing granulate system and possible future locations. Then they calculated the required outputs and researched suitable manufacturers that could supply a practical and reliable vacuum transport system. Once the team knew how large the new equipment was likely to be and how much space they had available, they began to build up the possible layouts.
John Bennett, continues: “There were a number of obstacles preventing the best plant layout however, some could not be moved such as the plant’s building trusses, others might affect the operators or how the equipment would be maintained. We identified each and talked through the consequences with a team comprising of maintenance, production, health and safety and management.
“One of the obstacles was proving that the proposed equipment was capable of the required output without damaging or changing the granulate. We organised production trials at the supplier’s test plant. These proved that the proposed solution would work, being both clean and simple.”
Once the trials were completed the team developed the design, taking all these considerations into account. The design solution was presented at a site meeting using SolidWorks to display a 3D image. This helped ensure that also non-technical staff could appreciate the design solution.
As system trials were required, the actual project took four months to complete, despite the design and manufacture phases taking less time than anticipated. Limited headroom meant that a crane could not be used, so much of the structure was supplied in pieces so they could be manhandled into position.
Rich adds: “We have significantly reduced operational hazards, increased recycling capacity so that we can save more granulate and get it back into the manufacturing process once again.”
Bennett concludes: “Our new design not only meets the requirements of both production and maintenance needs within Marley Eternit, but it also offers features which go beyond the original design requirements. They are now able to completely empty the system which means that changeover times are massively reduced and cross-contamination is completely eliminated for the first time.”