It was frequently a judgement of the maintenance personnel when to rotate the tires and when the tire was fully worn it had to be discarded and replace. Some suppliers would take these worn wheels and coat them with urethane but the result was a wheel which did not meet the original, optimal design specifications for wheel weight and size which would reduce the mixing efficiency of the wheels and stress the performance of other components such as shafts, bearings, etc.

In 2019 Simpson introduced a completely redesigned urethane muller wheel for the G series Simpson Mix-Mullers and Simpson Multi-Mulls. These new wheels are designed to provide exceptional performance in terms of wear and cleanliness and significantly reduce maintenance.

Each wheel has been designed to feature a cast iron core and a urethane outer layer that maintains the original wheel design weight and size in order to assure optimal mixing performance. Since urethane is less dense than cast iron, as the urethane wears less weight is lost when compared to traditional iron wheel.  As the urethane wears the cast iron core will maintain the significant majority of the desired wheel weight.

To signal to the maintenance staff that it is time to rotate the wheel two sets of wear indicators are fastened to the cast iron core and embedded into high visibility yellow urethane. The yellow urethane is bright inside the muller and when the outer edge of the wheel wears the urethane down to the “high” indicator the maintenance staff will know it’s time to rotate the wheel. The process will repeat again and eventually the second “high” indicator will be revealed and the wheel will be rotated again. This process will repeat until both of the “low” indicators have been revealed and the wheel has gone through 3 rotations. When the last “low” indicator is revealed it is time to remove the wheel from the machine and replace it with a spare. The removed wheel can then be sent to Simpson Technologies where the worn urethane and wear indicators will be removed and replaced. The wheel can be repaired for a fraction of the cost of a totally new wheel.

Lifting the wheel for rotation or removal has been dramatically simplified by placing four locations where a sling and lifting fixture can be attached through the wheel to securely hold the wheel to an overhead crane. All Simpson Mix-Mullers and Simpson Multi-Mulls also have removable mixer wall sections and dust hood sections that make it easy for maintenance personnel to enter the machine and remove large parts. Maintenance is safer and consumes less time for busy maintenance staff.

To complete the upgrade of the mixer interior we can also provide a mixer wall scraper and urethane mixer wall liners that will help to keep the mixer clean during operation and for maintenance.

All of the mentioned improvements are available to upgrade any G series Simpson Mix-Muller or Simpson Multi-Mull and can be retrofitted to a mixer during a normal maintenance cycle.