Autor: Roland Gruber , 18.10.2021

Canada, Bhutan, Costa Rica, Germany, Albania, Italy, South Africa – these are just a few countries where plant operators rely on the technical know-how of Austrian Braun Maschinenfa­brik GmbH.

The product range of the hydraulic steel engineering experts covers trash rack cleaning machines in a variety of designs. From large-scale to small-scale power plants, Braun has the
solution to all requirements and application needs. A few years ago the Vöcklabruck hydrotech industry specialists reacted to the increased demand for horizontal rake systems and are now able to offer this variation with the superior technology Braun is known for today.

Braun Maschinenfabrik, based in Upper Austria, has been engaged successfully in the fields of hydraulic steel engineering and the construction of trash rack cleaning machines for over 50 years. Braun offers individual solutions to power plants of all sizes with a comprehensive product range. Braun's portfolio covers conventional cable winches, hydraulic telescopic arm trash rack cleaners, fully automatic cleaning machines with articulated arms that are movable along tracks, as well as all usual types of trash rack cleaners. Braun's largest trash rack cleaning machine with an articulated arm is employed at the Sohlstufe Lehen power plant in Salzburg. This machine is a showcase project in its own right as the parameters for dimension and total weight have broken many inhouse records.

The trash rack cleaning machine with an articulated arm is a tool that moves along tracks and consists of a traction and a rotary drive. The balance weight, the booth, the switchboard and the hydraulic power unit are assembled on the rotating upper operating console. The main arm has a total length of 14 m and a weight of 5 tons and is also attached to the upper operating console. The cleaner rake is attached together with the grabber to the lower end of the 12.3-m-long articulated arm. During the cleaning process the rake tines of the cleaner rake enter the fine rack. At this stage the grabber is open and will not close around the collected debris until it reaches the water surface. The grabber bottom is rotatable and is put into the initial position during the cleaning process. After the cleaning process is completed the grabber bottom on the upper end of the rake is slewed all the way up. The collected debris falls into the rake through this “spooning-like motion”. Then the grabber closes and the trash rack cleaner moves to the container. During the emptying process the grabber bottom is slewed all the way down and the debris falls out of the rake. In this position the grabber is securely holding on to debris of any size. Within the last ten years many other extralarge trash rack cleaning machines with articulated arms were ordered, especially by the German energy suppliers EnBW and LEW/BEW for equipping various power plants on the Dan­ube and the Neckar River. An extraordinarily large unit for instance is used at the Knochendorf power plant on the Neckar River.

For some years now smaller hydropower plants have benefited from Braun's experience in the planning and execution of cleaning devices for large-scale plants. Because of the increase in orders by smallscale hydropower plant operators, Braun's engineers have adapted their collected knowhow of large-scale projects onto smaller power plants. The results are tailor-made telescopic arm trash rack cleaners offering the most reliable cleaning performance and an excellent costperfor­mance ratio, just as their “big brothers” do. For several years now there has been a trend toward the installation of horizontal rakes, both at newly-built plants and at renovated facilities – above all to protect fish populations. Narrow bar gaps of 15 – 30mm and low flow velocities enable the fish to extricate themselves from intakes. Greater protection for fish populations is a key argument in favour of horizontal rake solutions. Braun Maschinenfabrik produces horizontal rakes in the superior quality expected of the name, having begun to react to the increased demand for horizontal rakes several years ago. Braun stands for long-lasting, technically sophisticated, robust and reliable solutions. Proof of this can be found at numerous reference facilities, both at home and abroad, particularly the horizontal rake cleaning machines installed for the Höfen hydropower plant in Tyrol or the unit for the new Danzermühl hydropower plant on the River Traun, where a rake cleaning system was integrated to service a rake width of 48m.

Efficient Machine of Innovation
The corresponding effect on the plant’s annual capacity can only be achieved if a constant and unhindered flow of water can be guaranteed. Combined flow-optimised fine rakes and an effective and reliable rake-cleaning machines are still some of the most important infrastructural components of a hydroelectric power station – be it a vertical or horizontal rake installation. A fully automated and reliable, high-performance rake cleaning machine ensures the maximum flow is constantly guaranteed across the entire cross-section of the rake. As recognised industry specialists, it is these attributes that have also helped to establish Braun Maschinenfa­brik’s excellent reputation in horizontal rake technology. As a well-known non-stop engine of innovation this reputation has already spread far beyond the Austrian borders. The company’s list of references from the last few years provides some very convincing proof.

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MSOXE5126 web


Braun Maschinenfabrik’s horizontal rake systems prove their worth under difficult conditions.

photo credits: Braun

Knickarm RRM Sohlstufe Lehen web2


Braun Maschinenfabrik GmbH's largest trash rack cleaning machine with an articulated arm is employed at the “Sohlstufe Lehen” power plant in Mozart's hometown.

photo credits: Braun

83 KW Braun web


The horizontal rake system has proven itself to be reliable, robust and efficient.

photo credits: Braun

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Smaller in design, but with the same reliable working performance as its “big brothers": The telescopic arm trash rack cleaners by Braun Maschinenfabrik.

photo credits: Braun