VACUUM-PRESSURE IMPREGNATION PLANTS FOR WOOD PROTECTION WITH TOP AUTOCLAVE – IMP-VP-D series – As per E.C. rules
COMPLETE PROTECTION OF WOOD AGAINST DEGRADATION AGENTS USING PRESSURE-VACUUM TECHNOLOGY
The IMP-VP plants are suitable for treatment of items that fall into risk classes 3, 4 and 5 and are an effective repellent against the enemies of wood:
– marine organisms
– atmospheric agents
The natural conformation of wood makes it unsuitable for use outdoors.
Its composition (20-30% lignin 40-50% cellulose, 20-24% carbohydrates) makes it vulnerable to “degradation agents” which begin their action when humidity is high and the temperature is between 10 and 40 °C.
Fungi, mildew and bacteria are in ideal conditions to develop, whereas the ultraviolet rays present in the sun light photochemically decompose the lignin making it soluble in water.
The only way to fight the action of the enemies of wood is to turn to the help modern chemistry provides.
In fact if a good insecticide and fungicide is applied in sufficient quantity so that the internal parts of the wood are involved, the attack from micro organisms and insects can be offset for several years. Both the fungicide and the insecticide lose their effectiveness over the years, therefore the duration of the protection is directly proportional to the quantity applied. An impregnant with a high dry residual level can make the wood waterproof defending it against water as long as it is not applied so as to form a surface film.
The pigments, which are not transparent, form an impermeable surface barrier against ultraviolet rays, thus preventing decomposition of the lignin.
The traditional systems of dipping, brush painting and spraying are not able to guarantee to achieve the three results.
A product with a high dry residue level will form a surface film, limiting the penetration of the insecticide and fungicide solution.
On the contrary, a product with a low dry residue level will have better penetration allowing the insecticide and fungicide solution to be more active, but having very little resistance to the penetration of humidity into the internal parts of the manufactured item.
Only the use of pressure-vacuum technology has enabled pigmentation products with high dry residue levels (12-30%) to be applied resulting in complete protection of the item.
WOOD TREATMENTS BY PRESERVATIVE WITH SALTS DISSOLVED IN WATER: THE PLANT IMP-VP
It consists of an autoclave laid upon a bath to be intered.
The bath is used for the preservative storing, the autoclave for the wood to treat laying on proper carriage.
During the operative phase the preservative passes from the storing bath to the autoclave which contains the timber and after having performed the impregnation, it comes back into its former container.
All the process is by automatic cycle.
The plants work by using a maximum vacuum of -730 mmHg. and hydraulic overpressure of 12 Atm. and then may perform impregnation cycles by full-cell, empty-cell or only at the pieces pheriphery.
It is the ideal plant for the treatments by preservative with salts dissolved in water.
A standard plant is made up of:
An autoclave capable of resisting a vacuum of -700mmHg at a pressure of 12 atm.
Storage tank for the impregnant.
A small sized preparation tank for the impregnant.
A vacuum pump.
A high-pressure pump.
An electric switchboard panel with a microprocessor, with the possibility of connecting it to a personal computer.
Should the plants be “off the ground” the possibility exits for structuring the plant with an autoclave positioned higher acting as a storage tank for the solution.
The reduced sizes compared to the productivity of these plants allow considerable savings in terms of space and they are easy to place inside the company.
The quality of the materials used in manufacturing the autoclave, such as stainless steel, guarantees long life against corrosion and the components have all been selected from leading Italian and foreign companies, giving a high level of reliability.
These characteristics, common to all ISVE plants are reflected in the high impregnation quality achieved in a short time and with very limited operating costs.
THE IMPREGNATION CYCLE OF WOOD USING VACUUM
Phase 1: Initial Vacuum
The pile of wood, once positioned on the powered trolley of the autoclave, is placed inside the plant to start the cycle.
The hermetic closing of the door enables the machine to begin treatment by starting the vacuum pump. This phase, which is very important for the success of the cycle, frees the pores of the wood of air, by generating a “vacuum” which will allow the wood “to breathe” in the preserving solution.
The length of the vacuum phase can vary from 30 to 90 minutes according to the characteristics of the wood.
Phase 2: Filling
Once the first phase is over, the vacuum is used to convey the treatment solution from the lower tank to the autoclave positioned above.
A level sensor that sends the plant computer a control signal controls the filling phase.
Phase 3: Application of pressure
The 3rd treatment phase has the important task of “forcing” the solution into the wood. The pressure pump may operate for from between 30 to 180 minutes depending on the characteristics of the wood.
The combined action with the vacuum will enable the active principles to establish themselves deep in the wood thus guaranteeing long lasting protection.
Phase 4: Discharging the solution
On termination of the treatment phases, the solution not absorbed by the wood returns to the lower tank by means of a discharge valve positioned on the bottom of the autoclave.
Special automatic systems top up the salt contents and restore the level of the impregnant so that it is ready for a new cycle. All solution not absorbed is available for a new cycle without any waste.
Phase 5: Recovery vacuum
A further vacuum phase lasting about 20-40 minutes facilitates the bonding of the active principles of the wood.
This phase is important in the “dripping” phase of the material being treated.
Phase 6: End of cycle
At the end of the impregnation cycle the autoclave returns to atmospheric pressure and the wood is ready for the following phases.
Duration of the process
The duration of the cycle varies depending on the following factors:
– Characteristics of the wood
– Quantity and concentration of the salts required to be administered
USE OF IMPREGNATORS IMP-VP TO PROTECT WOOD EXPOSED TO EXTERNAL WEATHER CONDITIONS
The use of vacuum-pressure impregnators is advisable for all those products, such as
– garden furniture
– prefabricated elements for building
– platforms for trucks
– ship fittings
– piles in agriculture
which are exposed for varying lengths of time to external weather conditions.
In the same way, treatment of all those exotic and non-exotic woods with insecticides is indispensable in that even if only used indoors, they are subject to woodworm and other similar xylophages.
The products that can be used in our plants are:
Solvent based IMPREGNANTS having a protective, exterminating action against mildew, insects, bacteria
Salt based IMPREGNANTS dissolved in water having a protective, exterminating action against mildew, insects, bacteria
Fireproof salt based IMPREGNANTS dissolved in water having also a protective action.
ADVANTAGES OF VACUUM IMPREGNATORS
There are many points in favour of this type of investment. Here following are the most important:
*Low capital investment
– Very few investments in the wood industry can be compared to the capital investment over thousands of cu.m. of treated wood a year, as an IMP-VP plant.
*Low labour cost
– One person in charge for each work shift is sufficient to manoeuvre, unload and load the plant, as long as there is a mechanical means of handling the piles of wood.
*Wide and expanding market
All that is required is to evaluate the customs entry for imports of treated material to assess the available market space.
*Low maintenance costs
If care is taken in keeping the plant clean, the maintenance costs are very low as there are very few moving parts.
Not only can the material be treated with a humidity of 30%, but, the material can be used and handled without problems only a few days after treatment.
*Easy to adapt to market requirements
Thanks to the limited labour required it is easy to face variations in production without creating serious problems.
*No form of contract is required for impregnated products
The customer is free to move on the market without any form of restriction
*No danger of ruining the material
IMP-VP plants are supplied with an electric control panel equipped with a microprocessor (Vacutronic system) which minimises the possibility of an erroneous manoeuvre.
Connection to a normal PC means all the cycle phases for RAL certification can be visualised and printed
IMP-VP-D-1500/6000 – autoclave L. 11500 / top autoclave L. 12000
IMP-VP-D-1500/9000 – autoclave L. 16800 / top autoclave L. 18000
IMP-VP-D-1500/12000 – autoclave L. 22000 / top autoclave L. 22000
IMP-VP-D-1800/6000 – autoclave L. 16500 / top autoclave L. 17000
IMP-VP-D-1800/9000 – autoclave L. 24000 / top autoclave L. 25000
IMP-VP-D-1500/12000 – autoclave L. 32000 / top autoclave L. 34000