Production Technology

Wouters-Tecnolub, 4890 Thimister, Belgium

Efficient oiling – just a must – for AAC production

Wouters-Tecnolub has therefore developed a lowpressure oiling system whose design has indeed taken into account the many troublesome problems that producers may face:

In the case of reduced oil quantities, problems with adhesion are likely to occur. As a result, there may be difficulties in removing the cake from the mould. Furthermore, mould cleaning operations can turn out to be a real nightmare ending up with extra costs.

In the case of excessive oil quantities, on the other hand, producers will have to face oil spills resulting in pollution and the certainly undesirable gradual development of oil leftovers in concrete recycling hoppers.

Calculating a perfectly appropriate minimum quantity of oil as such may be easy. However, finding the best way to spread the oil in such a manner that a uniform layer with the accurate quantity is achieved, and employing fully automatic operations, will probably be a more complicated endeavour. Thanks to the low-pressure technology that Wouters-Tecnolub has developed, the spraying devices forming part of this technology will allow producers to easily define quantities ranging from 10 to 100 g/m². This user-friendly technology is capable of achieving the minimum quantity needed to spray it in a uniform and even layer without polluting neighbouring surfaces.

Does sufficient oil everywhere mean pollution and overconsumption?

Pollution such as oil spillage on the ground is often a result of low-tech spraying systems or manual operation. Two kinds of pollution can be observed: oil mist and overspray. A classical oil spraying system working with high or medium pressure will be bound to generate oil mist/ fog because the size of the droplets is not controlled. Subsequently, as soon as the size of a droplet will fall below 20 μ, it will start to volatilize and hence cause the occurrence of pollution such as oil mist/ fog. Particles of oil contained in this mist and in the cement dust present in this work environment will then mix and tend to stick on the equipment. Cleaning operations subsequently undertaken to get rid of this pollution are time consuming and expensive.

Another disadvantage occurring with these kinds of devices is that spray cone diameters are very hard to adjust. That is to say, when the device attempts to reach the edge of the mould, the spray will tend to exceed the focused area to be sprayed. This phenomenon is called “overspray” and will create pollution in the form of spray leftovers spreading across the floor of the plant. The use of expensive equipment like exhaust systems or suction hoods can try to reduce the occurrence of such pollution, but will not solve the actual problem itself.

The solution: low-pressure oiling

Equipped with its own low-pressure technology (0.5 bar), the Wouters-Tecnolub technology has been providing unique oiling solutions to this effect for more than 25 years. Thanks to this coaxial technology, oil and atomizing air arrive at the SB35 nozzles via separate circular systems. Oil micro-droplets are extracted during airflow and remain locked in the same to prevent the occurrence of oil mist. Wouters-Tecnolub has developed an ideal spray cone angle. This allows for a 5-cm diameter spray spot effected at a distance of 20 cm. Wouters-Tecnolub spraying ramps will then be able to apply just the right quantity of oil in a uniform layer without any dry (uncovered) zones.

It is simple to adapt the size of the ramp to any mould’s dimensions. Its “U” framework will shorten oiling times by spraying a multitude of mould faces at the same time.

Significant oil savings

This unique Wouters-Tecnolub low-pressure technology offers multiple benefits such as:

  • Easy adaption to achieve minimum quantities
  • No pollution
  • No need for air extraction system
  • Very high spraying accuracy
  • Easy maintenance
  • Reduced cleaning operations

The technology

These low-pressure spraying systems are composed of:

  • Electrical control cabinet to be able to adapt the different parameters of the system via PLC:
    • Oil temperature
    • Oil pressure
    • Air pressure
    • Oil circulation (heating system)
  • Hydro-pneumatic cabinet with heating tank
  • Spraying ramp

A solution for every kind of production process

Closed moulds

ing for varying dimensions is used to enter the mould in order to spray all faces simultaneously. This solution requires a ramp movement along one or two axes.

One-axis movement – up / down:

  • In this case, the mould moves smoothly underneath the oiling station by simply installing an appropriate structure capable of moving up and down.

Two-axis movement – vertical / horizontal:

  • One-axis movement is not always possible. If the mould does not move as smoothly as desired, oiling quality will be affected, meaning that the oil layer will not be uniform. For this reason, too, the abovementioned appropriate structure must be installed. The ramp will go down into the halted mould and will then move forward along the mould to apply oil onto all its faces.

Wouters-Tecnolub devices are driven by four separate hydraulic circuits capable of enabling and disabling operations whenever needed to oil all mould surfaces properly.

Open moulds

In this section, an “open mould oiling station” is described. After a release operation, the mould will open to be brushed. Once cleaned, the mould will then be oiled and will close again to continue the production process. Wouters-Tecnolub has developed a fixed straight ramp, also driven by hydraulic circuits to spray only focused areas whenever this is needed. This is an easy implementation of an oiling system with large oil saving potential compared to a roller system.

Cutting frames

Wouters-Tecnolub can produce systems to oil the frames for cutting operations. Every liquid can be sprayed, however, with some conditions existing. The oils used in AAC production have certain peculiarities. To be efficient, they must be very viscous. This is due to the fact that they have to adhere to vertical surfaces but must also be able to resist the pressure of the concrete during the mould filling process. Degrees of viscosity will also change during winter or summer times. The same oil with different viscosity levels will make the difference in the oiling process.

In order to avoid this problem, Wouters-Tecnolub equips its oiling systems with heating tanks to guarantee a constant oil temperature level and hence its viscosity. Provided with a 20-litre tank and oil level sensors, this system is able to fill itself in a step-bystep manner to maintain the entire content at the same temperature. In addition to this tank, Wouters- Tecnolub has created a permanent circulation system for the entire system. This system features copper inside every pipe to ensure thermal inertia. In this manner, and in addition to being fully automatic, the system runs completely on its own, meaning that parameters remain the same all year long.

With international corporations such as H+H, Xella and CRH as its customers, but also some local producers like Solbet and Brukbet, Wouters-Tecnolub is demonstrating its capabilities in terms of oiling solutions for the AAC industry.

Rue de l’Avenir 14
4890 Thimister, Belgium
T +32 8733 1707>