Rotary winnowing machine
The Rotationsworfelmaschine even winnowing , pulverizer , Kornfege , wind faces , Fegemühle , Blähmühle , cereal winds , cereal woe or corn plaster mill u. v. a. called, is a machine for cleaning grain that works on the principle of air separation. It is partly still used today in China or in developing countries, but also occasionally in Europe and the USA.
How it works and uses
A rotary winnowing machine separates the chaff from wheat , millet , rice or other grains by means of a wind wheel set to rotate by a hand crank . First, the threshed grain (including the chaff) is filled into a hopper and fed through a steady stream of air created by the wind turbine in an air duct. Due to its lighter weight, the chaff is blown out of the machine by the air flow, while the grain and other remaining heavier foreign bodies remain in the machine and are then separated from one another by vibrating sieves.
In addition to grain cleaning, the machine can also be used in other areas where components of different weights need to be separated from one another. In the Eichenau Peppermint Museum, for example, a wind sweep can be seen that was previously used to separate dried peppermint into the lighter leaves and the heavier stems.
history
In the history of agricultural engineering , wind sweeps are one of the oldest known machines . Although in the Chinese Empire as early as the 2nd century BC. Chr. Known, they were only used territorially limited. The machine was expensive, so that in the end it was only used sporadically in the more affluent southern China for the rice harvest and was usually loaned out in order to share costs. Nevertheless, it represented a head start over Europe, where chaff and wheat were thrown into the air by hand or with shovels so that the wind carried the chaff away, or the similarly laborious winnowing ("grain swing") used.
The Dutch first used these machines in Europe in the 17th century, although technology transfer from China is considered rather unlikely. Although its effectiveness has been established (two tons of grain per day versus 45 kilograms per hour), it was only used sporadically, as it ultimately turned out to be unprofitable due to the high acquisition costs and the need for maintenance. It was not until 1710 that the further development of the screen wind sweep made the process cost-effective and prevailed.
In Europe, wind sweeps were largely replaced by threshing machines in the second half of the 19th century to the beginning of the 20th century . These, in turn, were later replaced by combine harvesters in the 20th century .
literature
- Uwe Meiners : The grain sweep in Central Europe. Verbal and factual studies of the history of an early agricultural machine. F. Coppenrath, Münster 1983, ISBN 3-88547-216-3 , ( full text as PDF )
Web links
Individual evidence
- ↑ Clean the grain. In: irreler-bauerntradion.de. Irreler Bauerntradition, accessed on April 18, 2018 .
- ↑ Uwe Meiners: The grain sweep in Central Europe. See the table of contents, with many old expressions.
- ^ Meyer's Large Conversational Lexicon. Volume 7, Leipzig 1907, pp. 767-76: Grain cleaning machines at Zeno.org .