In-house-product-developments are distinguishing us in terms of quality from the conventional products of other suppliers:

One product development can be seen in the use of the Hollow-Flight principle, which was initially  made possible by a cooperation with the former Lurgi GmbH. This principle was incorporated in the seventieth into the company standard of Lurgi GmbH. As Lurgi GmbH was a pure engineering company, it started looking for a producer and came across Köllemann. The Hollow-Flight principle was initially advanced by Köllemann in the seventies in cooperation with Lurgi and already used in screw conveyors. Later on, the Hollow-Flight-Principle for screw conveyors was further developed and optimized by Köllemann GmbH. Today we are the market leader in the field of screw heat exchangers thanks to the use of this technology.

Our screw conveyors are designed according to the hollow-flight principle, which is a decisive advantage especially in the thermal treatment of bulk solids. In addition, the screw conveyors and the rotary valves can be equipped with a self-cleaning system, which enables the treatment of strongly adhesive and bridging substances.

According to the hollow-flight principle, screw flights are hollow, so that they provide a path for a cooling or heating medium to flow through. This means that bulk materials that have to be thermally processed, can be cooled, heated or kept at a constant temperature. Screw conveyors with conventional design only allow the heating or cooling medium to flow through the housing and optionally the worm shaft, where as the hollow screw flights of our KÖLLEMANN screw-heat-exhanger are used for heat or cooling transfer by means of a thermal medium along the entire length of the screw. With the active use of the screw flight as heat exchange surface, the efficiency of the thermal heat transfer of a screw heat exchanger increases disproportionately. The hot or cold surfaces of the screw flights are in constant contact with the bulk product and allow an optimum heat exchange .

The screw flight surface makes up more than two-thirds of the entire product-contacting surface of a screw heat exchanger. Thus, compared to conventional products, the Köllemann screw-heat- exchanger has considerably more area per meter of conveying path and thus a considerably higher efficiency.

The supplied heat is utilized to the maximum by minimizing radiation losses. This results in a multiple of the transfer capacity and is the only reason why applications in higher performance ranges can be realised at all. This process  offers great advantages in terms of maintenance, service life, efficiency and space requirements of the machine. This design allows maximum performance in the smallest space.

For some products, we have also developed self-cleaning systems. Our screw conveyors can convey products, which are not manageable for simple screw conveyors. This is achieved by two shafts, which rotate in the same direction and  guarantee a high lateral speed between the individual surfaces. To further enhance this effect, the second shaft rotates at twice the speed. With this unique system, KÖLLEMANN screw-heat-exchangers can even convey highly adhesive and bridging substances up to conditions comparable to Vaseline. Due to the high cleaning performance of the screw-heat-exchanger it operates with minimal residues on the screw shaft and offers consequently optimum heat transport.

Köllemann self-cleaning-rotary valves convince with forced cleaning , which safeguards a proper discharge of every kind of material.
A scraper located below the rotor is driven with the help of a synchronisation gear. This forcefully removes the adhering bulk product mechanically to achieve the best possible throughput and to avoid possible blockages.

Thanks to the precisely matched cleaning curve, KÖLLEMANN rotary valves achieve optimum pocket emptying performance with minimised adhesions and residues.

The forced cleaning offers controlled conveying of all bulk materials that could not be handled by a non-cleaning standard model.Click here for image video

Your contact partner

Guido Fiedler
Chief Executive Officer

Hollow-flight screw conveyor