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Wood Recycling: The Eco-Friendly Innovation Is On Its Way
GREENJOIST, a 36 month project co-funded by the European Commission through the LIFE+ programme, is approaching its conclusion. The spiral joist extruder, thanks to this effective recycling tool, designed to protect the environment and nature, is near completion.
Four years after the design process commenced, and despite encountering three major problems which significantly slowed down the various steps to accomplish the system as it stands today, IMAL has succeeded in its mission to produce a top quality green joist at a competitive cost, designed to replace joists made from virgin wood which are widely utilized throughout various industrial sectors.
FIRST PROBLEM: Joists cracking due to uneven supporting surface
After the initial experimental stages, it seemed as though IMAL had managed to produce a functional joist, capable of supporting heavy weights.
The illusion of the preliminary stages rapidly faded though when IMAL encountered its first problem: the joists started to crack for no apparent reason. A host of tests and trials were immediately run to identify the cause and it was discovered that if the joist was placed on an uneven supporting surface (even if this was barely a couple of centimetres), the joist would crack at the point where it came in contact with the uneven surface.
Once the cause had been identified, a solution had to be found: by adapting the prototype it was possible to produce joists with the right requirements. The next step after the experimentation, was to tackle the problem of designing a prototype to produce different sized joists and cover all the market requirements. The IMAL strategy to have one spiral conveyor as a base and change the outfeed flange as required, would have kept the costs of the equipment down.
SECOND PROBLEM : the pressure of the material passing through the spiral conveyor, with the diameter required by the European project, is breaking the outfeed.
When IMAL began to adapt the equipment to the standards required by the GREEN JOIST project, the second problem emerged: with the diameter (80×80) required by the project, the pressure generated by the material as it moved along the spiral conveyor was causing the outfeed to rupture. This meant that it was not possible to produce the range of dimensions required utilizing the same spiral conveyor and this not only complicated the work further but the need for new mechanical items arose as well, with a consequent increase in cost.
As a result, IMAL had to go back to the drawing board and after a close review of the drawings of the equipment, a double spiral conveyor was designed to attenuate this friction.
THIRD PROBLEM: The increase in pressure is cracking the spiral on the conveyor.
As the prototype was adapted to meet European standard requirements, likewise the production of the joist had to comply with the Directives governing the industrialization of the product. The production speed targeted in the GREEN JOIST project is 2 metres of joist a minute, whereas the speed which IMAL managed to achieve initially was barely 80 cm/min. Pressure was increased in an attempt to accelerate production speed to reach the required production levels but this led to the third problem, the spiral cracked. After reviewing the drawings once again and repairing the spiral, IMAL has come to the conclusion that to achieve the targets set in the GREEN JOIST project, each joist format requires its own extruder.
