For many years, Mannings has used the same technology on numerous custom-built heating applications and has found that energy savings are often accompanied by faster production. For example, a low-voltage heating unit was recently supplied which eliminated a production bottleneck and increased output for James Walker, the gasket and seal manufacturer.
Mannings developed a design which would not only allow several metal tools of various sizes to be heated simultaneously to a controlled temperature of 170 degrees C but also maintain temperature uniformity within very tight limits. To achieve the quality required it was also essential for the tool to be heated uniformly to the correct temperature. This ensures that the seal rubber ‘flows’ to take on the shape of the mould when it is transferred to the press.
The new unit can hold up to 10 tonnes of moulds. These are placed on a refractory base and a mobile motorised cover is then moved over the base to form a sealed heating chamber. The heating system, which is incorporated into the base construction, consists of the ceramic heating elements laid in slots in the base brickwork so that the whole hearth area can be uniformly heated to ensure good thermal performance. A re-circulation fan has also been incorporated into the cover design as well as internal air distribution ducting. This helps to produce uniform heat distribution throughout the chamber. Tony Magorrian of James Walker said: `The new preheat unit has made a vast improvement since the tools are now warm enough to form within minutes and the in-built flexibility allows production to be varied as required.’