Windhexe (Wind Witch) – sort of like a dust devil, from the German

A very good example for the use of spiral motion is shown to us by the American Frank Polifka, who has been built a sort of cyclone for years producing remarkable effects with an artificial tornado. It transforms the nastiest waste to dry powder only by compressed air. The whole performance of this machine you can see at www.vortexdehydration.com.

Windhexe

Fig.: Windhexe by Frank Polifka

Vacuum cleaner

1985 the British engineer James Dyson developed a Hoover without a bag cleaning the air only by whirling through a swirl chamber, by the way an old principle with a great future. The air to clean is sucked tangentially in a cylindrical or egg shaped box and is blown out through the front end. Interestingly the „heavy“ particles accumulate in the centre, and it is possible to separate them.

Ranque-Hilsch-Vortex-Tube

Back in 1929 G.J. Ranque, while doing the experiments with a cyclone, found a temperature distribution and got a patent for this. 1948 R. Hilsch constructed the so called Ranque-Hilsch-Vortex-Tube. It is a simple pipe with relatively small diameter, in which compressed air (up to 8 Bar) is blown in tangentially. Also in this case one can see a separation of heavy (cold) and light (warm) air to blow out in both front sides. If cleverly constructed one can have cold air from a central hole at one side and warm air from a circular slit on the other side. The difference in temperature can be up to 1oo degrees and it´s possible to get up to -58°F (-50°C)! Since there are no moving or other components necessarily to repair the tube can be installed at inaccessible places for cooling e.g. electronic circuits. Unfortunately, the efficiency factor is not very good and therefore the use for air separation or for cooling machines is not possible in the near future. A company producing Ranque-Hilsch-Tubes is vortec, or exair.

Wirbelbirne (spiral bulb)

In industry huge amounts of gases are cooled. Mostly this happens by compressing the gases,which warms up and one can cool it with simple air. Afterwards the gas is decompressed through air regulators and is cooled down. It is possible to improve the energetic balance of the process by using a Wirbelbirne instead of a simple air regulator. It works like a Ranque-Hilsch-Tube. It is possible to cool the warm gas stream created a second time efficiently.

Wirbelbirne

Fig.: Wirbelbirne

Cyclone chamber

At the website www.tornadoproject.com one can order a construction manual for the device I would name “Wirbelkammer” or cyclone chamber. It is not completely useless ;) but you can create a tornado in an uncomplicated way. One can create this natural phenomenon at any time and watch it. I can tell you it is a great experience. I have built it, and everybody who has seen it, was quite stunned, like me.

Separation by cyclone-like pressure vessels

Yet for decades devices using the Ranque-Hilsch-Tube principle (cyclones) have been used for the separation of solids and fluids from gases (vacuum cleaner). They are ranging from a few centimetres to some meters in length.

Interestingly the principle is rarely used, only a few devices are to be found on the market even though various applications are possible. A good one is the cleaning of water, today mostly accomplished by more expensive filtration.

Zentrofan Mill

This grain mill was built in the second half of the forties last century by the German engineer Wilhelm Schulte. He wanted to treat the grain in a organic manner, and he found it in a novel way. The corn is to be fed in the middle of the mill at this moment an air stream grabs the corn, whirls it around and brings it to the inside of the mill, a basalt lava millstone, rubbing at the millstone constantly and turns into micro-milled particles of flour. The continuously swirling air stream removes the flour out of the chamber. It generates an extraordinarily high quality of flour, unbeatable in it´s grain size.

These days the mill is produced in little units by Rainer Braunwarth in 88662 Überlingen (www.zentrofan-muehle.de).

Zentrofanmühle

Fig.: Zentrofan mill