|
The logs are then debarked using
any of the three large de-barkers and proceed from here to the various
finishing machines i.e. pole peeler, Bezner rounding machine, Saw
mill etc. (depending on the end product required). Our machining
division can process a range of popular profiles from semi round
rails to tongue and groove interlocking timbers. We also have a
machine stress grader and proof tester enabling us to produce in
accordance with the new structurally verified timber standards.
Once the green processing stage
is complete it is on to the Kilns. Poles, Piles and critical use
timbers are subjected to a high pressure, high temperature steam
charge. This opens the cells in the timber to enable maximum treatment
penetration. A stand time of at least 24 hours is required to cool
the timber before moving on to the final stage of processing (the
treatment stage).
The treatment plant is capable
of treating poles of up to 27 metres (88 feet) in length. The timber
is placed in the cylinder where it is cycled under pressure in CCA
Oxide (copper, chrome, arsenate and oxide) using either the alternating
pressure method (APM) where the treatment cylinder is flooded and
held under a repeated pressure cycle for several hours or the Bethel
or 'full cell' pressure method depending on the product being treated.
Much of the Croftpole and Croftpile
product now goes through an accellerated fixation process to minimise
leaching and improve production times.
|