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RAPID IN-LINE TREATMENT PLANT
Introduction:
The Uniplant is the first commercially viable rapid treatment plant available to the timber treatment market. While it is correct to say that the idea of low pressure rapid treatment is not new, the Uniplant has been designed to meet two criteria:
1. Full sapwood penetration
2. It can be installed in an existing production flow to keep pace with the required rate
Design:
The plant consists of a treatment vessel, similar to normal plants, except that it is much smaller in cross-section, rectangular, and is long enough to take the longest timbers to be treated. Clever engineering ensures the rapid entry of the timber into the vessel, fast door closure, very fast transfer of the solution, fast vacuum and, where necessary, fast pressure, all to effect a rapid treatment cycle. This cycle time would be less than two minutes and can be as short as one minute.
MARKET
It is aimed at the H2 treatment markets, as a superior product to spray or dip treatments. However, there is no reason it can not be used for H3 treating. The preservative can be of any type; waterborne BT Wood is the obvious most economic type for H2, but alternatives such as solvent based boron are possible. There are many options to look at for H3, including the tried and true CCA, LOSP options and new oil type treatments for decking. The type of preservative used is very flexible, and indeed, they can be interchangeable.
DETAILS
VESSEL DIMENSIONS
The plant would be sized to be somewhat quicker than the production flow it is required to fit into. So, assuming a cycle time of two minutes, if the plant is to be installed following a planer which is running at say 50m per minute producing 90x35 at six metre lengths, the plant would need to take a minimum 16 pieces every charge. Say 16 pieces per charge, at 4 wide by 4 high, the dimensions would need to be about 400mm wide by 250mm high by 6.5m long. However, it may be preferable to make the timber up into normal packs and treat them as such. This then requires the vessel to be larger, thereby giving a greater volume throughput. Actual dimensions and production rates need to be assessed on a case by case basis.
OTHER EQUIPMENT
The remainder of the plant consists of a working tank which contains the working solution, a vacuum pump which is sized to pull a vacuum on the treatment vessel in the shortest time possible, pipe-work and valves to ensure the rapid transfer of liquid into and out of the treatment vessel.
The plant will be fully automated, including the door mechanism and the timber transfer mechanism.
TIMBER TRANSFER
The treatment principle is simple, but probably the most difficult part of the procedure is the transfer of the timber into and out of the vessel in the correct manner.
Depending on the space available and directional constraints, it is envisaged that the timber could be fed into the vessel from one end, and then out the opposite end.
TECHNOLOGY
The process would be automated in a black box type control system. The technology belongs to the CRC for Wood Innovations, a research co-operative based at the University of Melbourne at Creswick in Victoria. TimTech Chemicals is a member of that CRC and has the exclusive worldwide license to the technology. TimTech is looking to sub-license the technology to users in return for a royalty charge which would be payable to the CRC.
ADVANTAGES OF THIS TYPE OF PLANT
• Full sapwood penetration
• In-line treatment
• Small volume of solution within plant footprint
• No drip
• No sprays to escape into workplace
• No blockages, so everything guaranteed to be treated
• No further holding or heating required
• Flexible with respect to size
• Can be used with any preservative
• Can change from one preservative to another very quickly
• Economic capital cost, dependant on size, throughput and associated equipment required
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