GB2269976A

GB2269976A - Method and equipment for the preparation of wheat flour

Info

Publication number: GB2269976A
Application number: GB9316927A
Authority: GB
Inventors: Michael Andreae-Jackering
Original assignee: JACKERING ALTENBURGER MASCH
Current assignee: JACKERING ALTENBURGER MASCH
Priority date: 1992-08-25
Filing date: 1993-08-13
Publication date: 1994-03-02
Anticipated expiration: 2013-08-13
Also published as: GB9316927D0; GB2269976B; DE4228114A1

Abstract

Wheat flour is prepared by a method wherein wheat is purified by passing through aspirator 2, vibrator 3 and separator 4 to remove, grass, stones and other impurities before being husked in machine 5 with rotating drum 7 with brushes and outer pot 6 into which water and grain is fed prior to conditioning at 9 and 11 and milling in a standard impact mill 13. The flour may then pass through cyclone 15 to remove air and be separated into flour and bran in sifter 16. <IMAGE>

Description

2269976 1 Method and equipment for the preparation of wheat flour The

invention concerns a method for preparing wheat flour by milling wheat, whereby the wheat is purified and moistened before the actual milling is performed and afterwards sifted. Furthermore, the invention also encompasses the equipment necessary for implementing this method.

The common procedure is to purify and moisten the wheat whereupon it is allowed to settle before being transferred to the mill. In order to obtain a low mineral content of the final product using this method, it has proven necessary to mill the wheat in several stages in expensive roller mills.

The purpose of this invention is to allow wheat flour with a low mineral content to be prepared at significantly less expense.

This requirement is satisfied by husking the wheat before milling, thus removing the outermost layer from the wheat. This ensures that the constituents of this layer (cellulose, fibres etc.) are not in the ground material, thus reducing the mineral content considerably. Furthermore, the moisture, which is not just added during the subsequent storage in a conditioning vessel but, for practical purposes, also during the husking stage, is able to infiltrate the wheat endosperm more effectively and more quickly. This results in a noticeable reduction in the conditioning period and also in a better milling effect, thus rendering it superfluous to perform the milling in complex roller mills in order to obtain a low mineral content in the final product. A single-stage milling process in significantly cheaper mills, e.g. in an impact mill, suffices in order to obtain a mineral content of less than 0.7 % in the final product.

Further advantages and details of this invention are illustrated by means of the following diagram and a sample process.

The diagram shows that the wheat is fed via a balance 1 to purification stations consisting of an aspirator 2 (removal of coarse straw), a vibrating screen 3 (removal of other impurities) and a stone separator 4.

The wheat which has been purified in this manner is then fed to a husking machine 5, which can consist of an outer pot 6 containing a rotating drum 7. Brushes protrude into the resulting annular space 8 and husk the wheat grain, i.e. remove the cellulose layer, while water is fed into the pot.

The husked wheat is then fed to and stored in conditioners 11 via wetting conveyors 9 (conveyors into which water is dispensed) so that the moisture can seep fully into the wheat.

1 2 When moistened sufficiently, the product is fed via further conveyors 12 to a mill 13, which functions as an impact mill, for example, albeit with a high air content in the material to be ground. A mill 13 as specified by DE-OS 35 43 370 is suitable for this purpose. The rotor consists of several stacked disks, each with a large number of peripheral grinding plates and a common stator. In the grinding process of this mill which uses air as a carrier gas, the particles of the material to be ground are accelerated to a high speed by the great number of turbulent air streams generated by the grinding plates and thus collide predominantly with one another. These mutual collisions cause the particles to break apart. Only a small part of the grinding procedure is performed by particles of the material colliding with fixed or rotating machine parts. Since the mutual collisions of the particles in the air stream prevail, the material is subjected to particularly mild pulverisation.

This process has proven particularly effective for the grinding of temperature-sensitive products. Since the product is in turbulent air streams at all times, the heat which inevitably results is dispersed immediately. The moisture present is also absorbed by the air thus allowing damp material to be dried.

The mixture of air and ground material is subsequently fed to a filter cyclone 14, in which the relatively high air content is separated from the ground material. The material is then fed via a cellular wheel sluice 15 of the filter cyclone 14 to a sifter 16, in which the ground material is separated into flour and bran.

Sample process: EC wheat is fed via the balance 1 and the purification stations 2, 3 and 4 to a husking machine 5, in which the outer layer of the wheat is peeled off. Between 2 % and 8 %, usually approx. 5 %, are separated with respect to the total weight of the wheat. The mineral content of the husked bran is approx. 1.2 %. The mineral content of the wheat is reduced significantly to approx. 1.6 % during the husking process.

Wheat grain prepared in this manner is then stored in a conditioning vessel. The conditioning period is usually between 4-8 hours, depending on the nature of the wheat. Afterwards, the husked and moistened wheat is sent through a single grinding stage in a mill of the type ULTRA-ROTOR (trademark of the applicant). The ground material is sifted following the extraction of carrier air in a filter cyclone. A final sifting stage (200 l,1) separates the bran from the flour. The flour fraction has a mineral content of much less than 0.7 %.

The invention allows wheat flour with a very low mineral content to be prepared more quickly and at lower expense. Multiple grinding stages in complex roller mills are no longer necessary. In addition, the conditioning periods are much shorter (reduction from 12-16 hours to 4-8 hours).

Claims

Patent claims

1 Method for the preparation of wheat flour by milling wheat, whereby the wheat is purified and moistened before the actual milling and sifting processes, characterised in that the wheat is husked before milling.

2) Method in ace. with Claim 1, characterised in that the husking is performed in a husking machine (5) accompanied by a supply of moisture.

3) Method in acc- with Claim 1 or 2, characterised in that between 2 % and 8 % of the total weight of the wheat are peeled off.

4) Method in acc. with Claim 1, 2 or 3, characterised in that the husked wheat is stored in a conditioner (11) before milling.

5) Method in ace. with Claim 1, 2, 3 or 4, characterised in that the husked wheat is milled in one step.

6) Method in acc. with Claim 5, characterised in that the milling of the husked wheat is performed in an air current providing a high air content.

7) Method in acc. with Claim 5 or 6, characterised in that the milling is performed in a mill (13) functioning as an impact mill.

8) Method in acc. with one of the above claims, characterised in that purified wheat is husked in a husking machine (5) and stored in conditioners (11) for four to eight hours, that the husked wheat is ground in turbulent air streams in an impact mill (13) and that the ground product is fed to a 200 g final sitter upon extraction of the air in a filter cyclone (14).

9) Device for executing the methods in acc. With one of the above claims, characterised in that it encompasses the purification stations (2, 3 and 4), a husking machine (5), a conditioning vessel (11), a mill (13) functioning as an impact mill, a cyclone (14) and a sifter (16).