IMAL on MDF YEARBOOK magazine, 2012-2013.
DYNASTEAM : New Steam Technology For Mat Preheater
IMAL’s patented method for injecting steam into the mat prior to pressing does not create condensation or spots. This new patented method is rather unique and the results are excellent. “The pre-heater can be installed on any kind of continuous press, it does not require foundations, and takes just one day’s production shutdown to install. Benefits gained with this application include the following”.
Production capacity increase
Saturated dry steam injected into the two surfaces superheats the mat so that the core reaches 100°C well before it would normally do. This increases capacity on MDF lines by over 20% and the additional costs only apply only to wood, resin and power. Steam requirements are very low at around 1 t/h for a line producing 1,000 m3/day of MDF.
Fixed costs are not affected hence “excellent profits may be made”.
Some plants do not have extra drying capacity, or wood preparation to handle an increase in production, but this does not mean that other benefits offered by Dynasteam should be excluded. At each maintenance shut-down or for some other reason for example, the bins are normally full when the line is restarted. “However, if Dynasteam is installed the line can operate 25% faster, while the material is still in excess. Furthermore, production capacity remains the same with all thicknesses across 12-15mm board or 38-45mm board.
Production losses restricted
if the type of resin used is changed to E0 instead of E1 for instance, the press factor can decrease by up to 18%. However, “by using the Dynasteam this loss is easily regained” by a return to the same production speed obtained with the other resin.
Better degassing process
The wider an MDF line, the more likely it is that the internal bond is lower in the centre than at the sides, because degassing is more problematic in the centre. With the application of the Dynasteam, it has been noted that the internal bond is more homogenous over the entire width of the board.
Better surface profile
The steam softens the two surfaces of the mat as it enters the press, making it easier to compress. A significant and immediate improvement is seen in the density profile when steam is applied.
Less porous surface
The steam greatly reduces the pores on the two surfaces, resulting in a more compact surface. The results of the toluene test are much better and a significant reduction in lacquer consumption will be noted during the lacquering process. “Some customers report that they have managed to decrease lacquer consumption by as much as 20%” with the obvious effect of lowering their costs.
Lower formaldehyde emission
“Less formaldehyde is released with a tighter and more compact surface and customers who have installed our Dynasteam report a reduction in board formaldehyde emission”.
Less mechanical strain, less maintenance and longer lifetime
Since the two mat surfaces are softer, the mat is easier to compress and consequently the main drive motor tends to absorb less current. Absorption on an MDF line in Italy for example, has dropped from 240A to 200A, clearly putting less strain on the chains, less wear on the steel belt and naturally reducing the amount of oil consumed. A decrease in pressure of 50-60 bar has also been noted on the hydraulic cylinders due to the effect of the steam on the fibre.
Reduction in resin consumption
By slowing down line production speed, an increase in cure time will improved board property values, in particular in the internal bond value. For various reasons, when steam is injected into the mat, it may not be possible to increase production capacity due to insufficient material, insufficient drying capacity etc. But by maintaining the same production speed, this will have exactly the same effect as increasing board cure time because 100°C is reached much earlier. “As a result, injecting steam into the mat at the same line speed, will increase internal bond values and hence reduce the amount of resin applied. The success of Dynasteam is well proven in that around 43 units have been sold over some 23 months.”