Plansifter

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Plansifter with typical suspension on wooden sticks

A plansifter is a sifter in the mill for separating the grain components that arise after grinding on the roller mill in a mill.

technology

Through the separation process of sieving and layering, the ground material can be divided into components of different densities (in the case of flour this means different mineral content). The circular movement in a horizontal position causes the product to be stratified according to its specific weight so that the heavier particles come into direct contact with the sieve and the lighter parts float on top .

In each plansifter there are several viewing compartments with stacks of sieves that contain 8–32 sieves, depending on the design. So-called sieve cleaners run under each sieve layer (nowadays usually tilting cleaners) so that the sieves do not clog. The sieves in a sieve stack have different mesh sizes (approx. 100–1000 µm), so that a separation into flour , haze , semolina and coarse shell fragments can take place. Each sieve layer therefore has two outlets: a sieve deflection and a sieve dropout (see particle size diagram). The flow pattern and the screen coverings within a screen compartment can be changed individually so that a wide variety of product guides are possible.

history

Plansifters for flour were invented by Karl Haggenmacher in Budapest in 1888 and replaced hexagonal sifters and centrifugal sifters. In the mills that were usually operated with wind or water power at that time, the plansifters were made to vibrate by means of force transmission and an imbalance (forced running). In order to be able to swing freely, the devices, which weigh several hundred kilograms even in small versions, are often hung from the ceiling with flexible bundles of bamboo or rattan rods. This typical suspension can still be found in today's electrically rotated plansifters. A free-swinging plansifter, the construction principle of which is still used today, was presented in 1912 by the Amme, Giesecke and Konegen company (Braunschweig). The Kreuzjoch plansifter is a more recent development . In this construction, the sieve stacks are arranged opposite one another in such a way that the swing weight can be dispensed with as in the conventional construction, thus saving weight.

  • Plansifter with two sieve stacks or compartments

  • Plansifter drive in the middle

  • Sieve layers

  • Particle size scheme

Individual evidence

  1. ↑ a b c Peter Erling (Ed.): Manual flour and peeling mill. 2nd, revised, expanded edition. Agrimedia GmbH, Bergen / Dumme 2004, ISBN 3-86037-230-0 .
  2. ↑ Technical specification of a square plansifter , PDF, accessed on August 13, 2014.
  3. ^ From Lueger: Lexicon of the entire technology .
  4. ↑ Technology of the Kreuzjoch plansifter .

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