Areas of Application

Special Industries

Roto-Fan® use in Alumina Plants

Reduce your Energy Consumption significantly in achieving spotless clean pipes (down to the bare metal) in Digester Pipes, Heat -Exchanger tubes, etc.

A pipe-cleaning procedure with high-pressure is well known in Alumina-oxide-plants. A high-pressure hose with a retro-nozzle in front is normally pushed into the pipe to be cleaned. The nozzle itself is driven into the pipe by the reaction force and the retro-jets unevenly clean the pipe. Pressures up to 1200 bars and pumps of 350 hp are normally used. This method can be radically improved by using the


The fundamental difference to the ancient static nozzle method is that our nozzles rotates. The speed of rotation and the linear advance per revolution of the nozzle can be adjusted remotely at any time during the operation of the unit.

The manual handling of the high-pressure water hose during the operation is completely eliminated and the ability to negotiate and clean a great number of bends in pipes is greatly improved by reduction in friction resulting from the rotation of the hose and nozzle.

It has been found that the system is capable to work with almost the same efficiency from ID 10 - ID 5000 mm. Cleaning depths of several hundred meters have been achieved even if there were elbows, valves or similar restrictive passages in the pipe system to be cleaned. The space required in front of the pipe to be cleaned is less than 500 mm.

The linear advance synchronized with the rotation of the nozzle provides a thorough and even cleaning of the entire interior surface of the pipes. The resulting even smoothness of the pipe interior reduces the build-up rate of subsequent encrustation substantially compared with pipes that were unevenly cleaned static units.

The VELTRUP-Roto-Fan-System is only rotating and self-advancing semi-automatically high-pressure-water-cleaning-system currently on the market. In recent years, this system has been operating in a variety industrial plants, particularly in the chemical industry, where considerable problems or pipe encrustation occur.

It has been a very successful maintenance unit at many alumina plants all over the world. Substantial reduction in downtime have been achieved during this period. The main areas of application are:

  • Digestor Pipe Cleaning

    The removal of very hard encrustations in long pipe reactors (ID 80 - ID300 mm, cleaning length up to 150 m) with several 180 elbows.

    It was found that the pipe cleaning rate increased dramatically. No normal work was necessary during the cleaning procedure thereby reducing labour cost. The cleaning quality of the pipe interior was superb.

    Furthermore, the safety level was increased dramatically since the operator only has to control the cleaning process visually standing faraway from the hazardous cleaning accessories and the cleaning equipment itself.

    Typical cleaning rates between 1-2.5m/min. were achieved using a pump capacity of 180 1/min. and 800-1000 bars.

  • Heat exchanger Cleaning (insitu)

    It has been found that heat-exchangers (e.g. ID 20 - ID 80 mm) which due to the process get constantly blocked with extremely hard encrustations can be cleaned quite easily with the rotating system. After a cleaning procedure with the VELTRUP-Roto-Fan-System the operating time of the heat-exchanger between blockages was significantly increased. Furthermore, the yield of the alumina plant due to good heat exchanger were dramatically increased.

    Manual work was again avoided. The operator just had a control basic function, which especially on hit countries dramatically increased the cleaning volume per working shift.

  • Other pipe work, contaminated with:
    • aluminum-hydrate
    • aluminum-silicate
    • aluminum-calcide
    • ferrum oxide
    • magnesium-oxide
    • calcium-oxide
    • titanium-2-oxide
    • silicium-oxide

    Of all dimensions in the plant are successfully cleaned without being dismantled or dismounted.

  • Autoclaved, precipitator tanks or similar:

    Even with encrustations that couldn't be removed with hammer and chisel are cleaned with high cleaning rates.


Roto-Fan® Cleaning of Graphite-Heat-Exchanger


Inside graphite-heat-exchanger tubes sometimes scale is created which even results in total blockages. This scale very often is hard and can't be flushed away. On the other side it is not possible to operate conventional high-pressure-water-cleaning devices inside these tubes with more than 100 bars since the graphite is very sensitive against damage.


The VELTRUP Roto-Fan® System

A rotating high-pressure water cleaning device with precisely synchronized forward feed defined rpm of the nozzle is installed according to the picture below. The Roto-Fan® works independent of horizontal or vertical cleaning necessities. The Roto-Fan-unit itself is not moved at all during the cleaning operation. The work is performed by two operators, one of which indexes from one pipe to the xy-unit while the other one remotely controls the pump.

Due to exact rpm's and feed-ratio, the cleaning results are excellent. The tubes get absolutely clean and normally do not get damaged during this operation although pressures between 400-800 bars are normally used. The feed-ratio is determined by the sort of scale to be removed. On softer encrustations cleaning speed go up to 10 m/min. on harder scales the speed may be reduced down to approximate. 2 m/min. The time for indexing from one pipe to the next is approx. 5 seconds.

The following dimensions have been cleaned successfully: ID10, ID12, ID 20, ID 25, ID 32, with pipe lengths between 250-10000 mm per pipe.


The safety standard of the system is extremely high. The operator are not affected by splashing water, which is a significant improvement since rest remains of acids or alkalis are always of potential danger for the cleaning crew.