Objective
Steel or concrete surfaces have to be shot blasted before being painted or epoxy coated. The adhesion of the coating lasts seven times longer if the surface has first been shot blasted with grits. This machine will be dust-free and will perform a low consumption shot blasting on steel or concrete vertical surfaces. Shot blasting with a centrifugal wheel uses only 12% of the energy required to perform the same work with sanding nozzles.L%
The machine motorised with a 10 kW is able to work out 25 m²/h, with a finish of SA3 (the SA3 finish is a swedish norm and it is the best finish in the shot blasting field).
The first handling of the machine was monitoring step by step from an electric cupboard. After that we have made a complete automatic handling. But this complete remote control is expensive. Now, the last solution is in between; the remote control is not completely automatic and the operator has to order some functions.
Some improvements in the handling has been made after the end of the project.
For example, we have put all the hanging system in the floor. It is easier to place it and customers are more satisfy. In another hand, the shot blasting machine is better apply in the wall which is a big advantage.
We have made test of shot blasting in a big tanker and the work done was perfect. The only think that the customers ask us to improve is the hanging system. So we built up a new hanging system we place easily on the floor.
The machine is able to shot blast, in SA3, 25 m²/h to 40 m²/h with a 7.5 kW in the wheel. The shot blasted strip has a width of 33 cm which the overlapping is about 3 cm, thus we shot blast a strip of 30 cm effective.
The rotation of the wheel is 6000 RPM, diameter 215 mm. The moving of the machine is, in phase of shot blasting, 1.4 m/min.
We shot blast always in the upper direction, from the bottom to the top position.
The efficiency of the machine is :
25 m²/h - 40 m²/h
power 7.5 kW
average 32 m²/h
specific energy consumption 0.23 kWh/m²
The machine is full automatic.
Shot blasting, or energetic scouring, consists in throwing metal grits (or sand) on surfaces that need to be shot blasted or processed in order to obtain a certain roughness before coating or painting them. Sometimes, it is just a matter of improving the roughness of the surface in order to obtain a better grip (highway, airport, factory, entrance,...). Two projection methods are being used today :
- expanded compressed air blasting where the grits are blown away with the air through the nozzle.
- mechanical projection through a centrifugal blast wheel which ejects the grits peripherally.
With the dust collector having a power of 10 kW, our vertical shot blasting installation requires only 20 kW in comparison with the 180 kW needed to achieve the same time production with compressed air blasting.
The collecting of grits and dust is made via the high residual energy that the grits still have after impact. Dust is drawn up through the same collecting canal by the air flow of the dust collector. This simple process is also used in horizontal shot blasting. As far as vertical shot blasting is concerned; the collecting canal must be properly adapted (shape, length, angle).
Grits and dust reach the top of the hopper. The grits fall back into it while dust is drawn up, collected and stocked in the dust collector. The grits that are in the hopper are then put back in use and are reejected on the surface being processed.
The machine is hung to a moving and powered winch placed on rails and covering a distance equal to one strip length at each pass. It is started up by remote control. The hanging system must be designed very carefully. Its simplicity will make the machine competitive and will avoid resorting to gigantic means to perform this kind of shot blasting. Moreover, it will be possible to shot blast in wet dock, as it is the case for ferries for the time being.
All the main functions of the blasting machine will also be started up by remote control.
Programme(s)
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Call for proposal
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DEM - Demonstration contractsCoordinator
4400 Herstall
Belgium