Blast cleaning is uniquely capable and efficient at delivering the pre-coating surface preparation required for components that must be able to withstand severe ambient conditions including heavy equipment for construction and mining, agricultural machinery, transportation and material handling equipment, and railway equipment and rolling stock.
When Dutch equipment manufacturer Delwi Groenink sought a better solution for prepping its various steel weldments for painting, the company enlarged its manufacturing depth with a new continuous hanger shot blast machine from Rosler.
Based in Enschede, Netherlands, the company designs and produces numerous products including placement systems for container pads. Its customers largely work within the material handling, offshore, and transportation sectors.
Prior to the new system, pre-treatment of steel components utilized various external job shops for manual shot blasting in labor-intensive blast rooms and paint booths. In addition to complex logistics, the process was also time-consuming.
To accelerate the manufacturing process and become more flexible, the company decided to bring these processes in-house and took over the job shops including their staff. To further optimize operations, Delwi Groenink invested in a modern shot blasting machine, which was placed in a new building adjacent to the painting facility.
The company selected Rosler’s continuous hanger shot blast machine RHBD 27/32-K after shot blasting trials with Delwi Groenink components in our Customer Experience Center in addition to demonstration of similar Rosler systems in the field, and Rosler’s technical service in the Benelux countries.
The RHBD-K is designed for continuous processing of single components and batches of multiple work pieces with dimensions up to 10 ft (3 m) long, 10 ft (3 m) wide, and 40 ft (12 m) long.
The blast chamber is manufactured from manganese steel. Easy-to-exchange, gap-free manganese liners are also added in areas exposed to the blast stream for added protection.
The required high blasting intensity is generated by 16 Gamma 400 G turbines, each with an installed power of 11 kW. The turbines are arranged vertically in two rows on the left and right wall of the blast chamber, with the two rows being somewhat offset from each other. Combined, the turbines throw approximately 5,000 lb (2,240 kg) of blast media per minute. This ensures excellent blast coverage and uniform preparation of all surfaces.
The special “Y” design of the throwing blades and the optimized media transfer in these Rosler high-performance turbines allow a highly fluidized media movement with little or no turbulence. Compared to conventional turbines of similar sizes, the resulting higher throwing and impact speeds produce a 15- to 20-percent-higher blast performance. Blasting efficiency is further improved by the concentrated blast pattern.
Moreover, both sides of the throwing blades can be utilized resulting in a doubling of the uptime of the throwing blades. All these technical features, along with the fact that the blades can be exchanged within only seven minutes, convinced the customer.
Once a steel weldment has been transferred to the transport truss, the RHBD-K recognizes that a component is ready to be blasted and transports it into the entry chamber. As soon as a sensor monitoring the front area of the blast machine signals that no people are present, the double-leaf door closes automatically.
According to the part-specific treatment program, all or some turbines then start up and blasting begins in the blast chamber. This blasting intensity can be adjusted with frequency inverters.
After completion of the blast cycle, the work piece is transported into the exit chamber, media flow is interrupted with shell valves, and turbines turn off allowing the operator to manually remove blast media and dust from the work piece.
Once finished, the operator leaves the exit chamber and signals another sensor to initiate and open the double-leaf doors so a transport truss can remove the work piece from the machine.
Designed to handle a media throughput of around 2.5 metric tons per minute, the media recycling and cleaning system includes an elevator, cross auger, and air wash separator.
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