Cost effective blast cleaning of weldments has always been a technological challenge for users. But if the reliability of the welded components in question can potentially affect human lives, quality and process safety are of particular importance. That is why a manufacturer of rescue lifting equipment and aerial ladders, decided to equip its existing shot blast machine for weldments with state-of-the-art turbine technology from Rösler. The customer chose the high performance Gamma 400 G turbines, which were installed step by step. This turbine exchange not only improved the overall equipment uptime, but it also helped reduce the energy consumption and improved the overall shot blast results by about 20 percent. In the meantime the customer decided to purchase a new shot blast machine from Rösler located in Untermerzbach, Germany. The new roller conveyor blast machine, specially designed for blast cleaning of welding constructions, will be used for processing different types of aerial ladder components and will be equipped with the already existing Gamma 400 G turbines.
Rosenbauer International AG, located in Austria, is a globally leading manufacturer of fire fighting and disaster management equipment. The company develops and manufactures special vehicles, fire extinguishing systems, equipment and telematics solutions for professional, corporate and volunteer fire brigades as well as solutions for fire prevention. The products, manufactured in Europe, Asia and North America, are in full compliance with all relevant standards.
State-of-the-art turbine technology improves the uptime of the shot blast machine
The plant in Karlsruhe is specialized in rescue lifting equipment and produces rotary aerial ladders and hydraulic platforms for use by fire brigades. An important stage in the manufacturing chain is the blast cleaning of the different ladder components after welding.
Explains Erwin Hoffmann, manufacturing team leader at Rosenbauer in Karlsruhe: “An essential manufacturing step is the blast cleaning of the ladder components after they are welded. We are using blast media with a pellet size of one millimeter. With this media size the ladders are not only cleaned, but tensions in the material are removed, and the surface is peened. To date the company used a blast machine that is more than 25 years old and equipped with eight turbines. Since the supplier of this machine does not exist any more, it was no longer possible to purchase the required original turbine spare parts. „The parts offered by various other suppliers, did not meet our quality standards. Generally they allowed us to achieve sufficient shot blasting results, but we faced frequent equipment down times“, reports the team leader. For this reason, about 4 years ago Rosenbauer decided to exchange the existing turbines step by step with modern turbine technology. At an exhibition Erwin Hoffmann found out about the TuneUp program. The Retrofit trade name of the Rösler Oberflächentechnik GmbH is specialized in the modernization of shot blast machines, be it the improvement of the equipment uptime and shot blast performance, the adaptation to changed shot blast specifications and, even, the optimization of the energy efficiency. Rösler TuneUp develops tailor-made solutions for the customers irrespective of who the supplier of the original shot blast equipment was.
20 percent savings – a significant improvement of the overall cost efficiency
Erwin Hoffmann continues: “After we had decided to utilize the Rösler Gamma 400 turbines in our existing shot blast machine, the company developed an operating cost analysis for us. Based on this we proceeded to exchange the existing turbines step by step, two turbines at a time”. The first exchange took place at the beginning of 2015, and the last existing turbines were replaced with the high performance Gamma 400 G turbines, with 11 kW drive power each, early 2017.
The special curved Y-design of the throwing blades, combined with an optimized media transfer in the turbines, generates a highly fluidized movement of the blast media. This generates a higher throwing and, subsequently, a higher impact speed of the blast media resulting in a 15 – 20 percent higher blast performance compared to conventional blast turbines of the same size. Moreover, their special design allows the use of both sides of the throwing blades increasing their usable life by a factor of two. Erwin Hoffman confirms this: “With the old turbines we could only use one side of the throwing blades, turning them around was not possible. Since each turbine is equipped with an amperage meter, also measuring the energy consumption, I found out that Gamma 400 G turbines are using around 20 percent less energy”.
Improved blast pattern improves pass-through times
Higher uptimes and lower energy use are not the only features of the Gamma turbines from Rösler. With each turbine exchange the blast pattern could also be significantly improved. Reports the team leader: „The welded ladder components pass through our overhead rail shot blast machine at a defined speed. Each time we exchanged two turbines we could achieve the required blast cleaning results in a shorter cycle time”.
A safe investment – also for the new shot blast machine
The move into a new building that changed the overall work flow, required the investment in a new shot blast machine at Rosenbauer in Karlsruhe. Because of its excellent experience with the Gamma turbines the customer decided to purchase the new machine from Rösler. The Gamma 400 G turbines already installed in the old shot blast machine will also be used for the new machine so that the investments since 2015 can still be utilized. Erwin Hoffmann concludes: “Our reasons for this decision were not only the lower consumption and wear rate. Important for us was also the better shot blast performance and the excellent technical service by Rösler”.
