EP0207105A1

EP0207105A1 - Hammer mill.

Info

Publication number: EP0207105A1
Application number: EP86900046A
Authority: EP
Inventors: Richard Schultz
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-01-02
Filing date: 1985-12-30
Publication date: 1987-01-07
Also published as: JPS62501340A; DK418886A; CA1251427A; FI863544A; DK418886D0; FI863544A0; US4690339A; EP0207105B1; DE3565634D1; WO1986003990A1

Abstract

Le broyeur à marteaux comporte une chambre de broyage (1) disposée horizontalement à la périphérie de laquelle sont répartis plusieurs canaux d'alimentation (4) munis d'un orifice d'entrée (7a) pour le produit brut à broyer. A chaque canal d'alimentation (4) correspond un canal de sortie (5) situé à côté du canal d'alimentation et muni d'un orifice de sortie (7b) pour le produit concassé. Les entrées (7a) et les sorties (7b) sont réparties alternativement et régulièrement à la périphérie de la chambre de broyage; celle-ci est ainsi subdivisée à sa périphérie en un nombre correspondant de segments de broyeur qui sont chacun délimités par un canal d'alimentation (4) avec un orifice d'entrée (7a) et un canal de sortie (5) correspondant avec un orifice de sortie (7b). Une installation de dosage spéciale avec des compartiments coaxiaux (21, 22) et plusieurs vis de dosage (23) est prévue pour alimenter en continu les canaux d'alimentation (4) avec des produits bruts différents à partir des compartiments correspondants (21, 22). Le broyeur ainsi que l'installation de dosage conviennent pour différentes matières en vrac et différents broyages et offrent des avantages particuliers pour la préparation de mélanges de fourrages.The hammer mill comprises a grinding chamber (1) arranged horizontally at the periphery of which are distributed several feed channels (4) provided with an inlet orifice (7a) for the raw product to be ground. Each feed channel (4) corresponds to an outlet channel (5) located next to the feed channel and provided with an outlet orifice (7b) for the crushed product. The inlets (7a) and outlets (7b) are distributed alternately and regularly around the periphery of the grinding chamber; this is thus subdivided at its periphery into a corresponding number of crusher segments which are each delimited by a supply channel (4) with an inlet orifice (7a) and a corresponding outlet channel (5) with a outlet port (7b). A special dosing installation with coaxial compartments (21, 22) and several dosing screws (23) is provided for continuously supplying the feed channels (4) with different raw products from the corresponding compartments (21, 22). ). The crusher as well as the dosing installation are suitable for different bulk materials and grindings and offer particular advantages for the preparation of forage mixtures.

Description

Hammer mill

Field of the Invention

The invention relates to a hammer mill with a grinding chamber, a rotor with hammers or beaters for comminuting coarse material and a device for feeding in coarse material and discharging the comminuted product.

State of the art

In hammer mills of the type mentioned, the rotor in the grinding chamber generally rotates about a horizontally arranged axis, the feed taking place in the upper region of the grinding chamber. Usually, a baffle formed as a sieve jacket is provided at least in the lower part of the grinding chamber, through which the comminuted product enters and is discharged from a collecting space surrounding the grinding chamber or the sieve jacket. Such hammer mills have a high energy requirement, since the comminuted product can hardly pass through the sieve jacket, is unnecessarily carried along and passes through the grinding chamber several times.

BRIEF DESCRIPTION OF THE INVENTION It is the object of the invention to provide a hammer mill of the type mentioned which enables comminution with significant energy savings and high efficiency.

This object is achieved in a hammer mill of the type mentioned by the features specified in the claims.

The invention is based on the knowledge that, in a hammer mill, the material fed into the grinding chamber is comminuted after a very short grinding path. When the feed material is hit by the hammers for the first time, there is usually extensive comminution, whereupon the comminuted product unnecessarily rotates with the rotor until it can exit through the screen jacket. The hammer mill according to the invention is advantageously provided with a plurality of inlets and outlets evenly distributed over the circumference of the grinding chamber in order to be able to ensure uniform rotor loading, even when the rotor is reversed in the direction of rotation for the purpose of using the hammers or beaters on both sides.

The inlet channels are preferably arranged in such a way that they feed the coarse material to the grinding chamber in a plurality of horizontal planes, in order to also allow full use of the rotor height. Thanks to the horizontal arrangement of the grinding chamber according to the invention with a vertical rotor axis, it is possible to arrange a large number of inlet and outlet channels distributed over the circumference of the grinding chamber in a simple and particularly advantageous manner, so that the material fed from above can be easily fed radially into the grinding chamber can. Since each inlet channel is assigned an outlet channel, which is arranged at a relatively short distance behind this inlet channel, the material fed in via each inlet channel can be crushed as a comminuted product immediately after it has been crushed when the hammers or beaters hit it, directly via the outlet corresponding to the outlet that follows Outlet channel are discharged from the grinding chamber. The shredded product is no longer dragged along unnecessarily in the grinding chamber as before. Due to the special arrangement according to the invention, the hammer mill is divided in the circumferential direction into a more or less large number of mill segments arranged one behind the other, each of which is limited by an inlet with the corresponding inlet channel and by an outlet arranged at a relatively short distance next to the corresponding outlet channel, whereby the rotor carrying the hammers or beaters is assigned to all these mill segments together.

The outlets provided according to the invention can be completely free, or optionally covered with sieves of different hole sizes, in order to allow the size of the product to be preselected. Two or more such screens can be arranged very simply on a common slide which can be moved in order to either leave the corresponding outlet completely free or alternatively to cover it with one of the screens. An embodiment of the invention is explained with reference to the drawings.

Brief description of the drawings

Figure 1 is a schematic front view of the hammer mill. Figure 2 is a schematic top view of this hammer mill. Figure 3 shows schematically two outlet screens. FIG. 4 is a schematic front view of a metering device for the material to be comminuted. FIG. 5 is a schematic view of the underside of the metering device according to FIG. 4.

Embodiment

How from. 1 and 2, a rotor 3 is mounted in a grinding chamber 1 on an essentially vertically oriented axis 2, which is driven by an electric motor 11. The rotor 3 is provided in a known manner and not shown here with hammers or beaters, the outer ends of which stroke the impact circle 3 shown in dashed lines in FIG. 2. In the arrangement shown here, three inlet channels 4 are provided on the circumference of the grinding chamber 1 and are connected to the grinding chamber 1 via three corresponding inlets 7a. The regrind fed via the inlet channels 4 is thus fed radially downward on the circumference of the milling chamber 1. Each inlet channel 4 is provided with guide elements 10 which radially feed the coarse material to the grinding chamber 1 or the rotor 3 in several horizontal planes. For this purpose, guide plates 10 are provided in each inlet channel 4 in the arrangement shown in FIGS. 1 and 2. It is also possible to use other suitable guide elements which, for example, can be raised to feed the material to be ground radially into the grinding chamber 1 at different levels. Each inlet channel 4 is also assigned a corresponding outlet channel 5 on the circumference of the grinding chamber, which is arranged at a short distance in the grinding direction, ie in the direction of rotation of the rotor 3, along the grinding path behind the respective inlet channel 4. These outlet channels 5 are each connected to the grinding chamber 1 via an outlet 7b. The inlet channels can be arranged in any other suitable way in order to feed the coarse material supplied from above radially into the corresponding mill segment on the circumference of the grinding chamber 1. The outlet 7b of each outlet channel 5 can optionally be covered with a sieve of a certain hole size in order to adjust the size of the shredded product discharged via this outlet 7b. Sieves of different hole sizes are advantageously arranged on a common slide 9, as is shown schematically in FIG. 3, for example. The screens arranged on the slide 9 in this case comprise two screen surfaces 8a and 8b of different hole sizes and a free through opening 8c arranged between them. If the slide 9 is displaced in the vertical direction relative to the corresponding outlet 7b in the manner shown schematically in FIG. 1, the free through opening 8c can thus be located at the outlet 7b, or the screen surfaces 8a or 8b can optionally be in this outlet 7b can be used when the size of the shredded product to be dispensed is to be selected. The arrangement of the hammer mill described and shown schematically in the drawing here comprises, for example and in order to simplify the drawing, three inlet channels 4 with three associated outlet channels 5, which are arranged alternately and are distributed uniformly over the circumference of the grinding chamber 1. The number of feed channels and the corresponding Auslauf¬ channels can be selected depending on ^{'requirement,} however, and the respectively desired grinding operation to be adjusted.

The hammer mill according to the invention is each divided into the largest possible number of mill segments or comminution zones, the distance between the inlet and outlet channels 4 and 5 being kept as short as possible and being practically zero.

Tests have shown that after the feeding of coarse material through an inlet channel 4, the comminution is largely complete after about 40 to 60 mm of grinding path. In one embodiment of the hammer mill, the grinding chamber diameter of which is 1500 mm, the outlet channel 5 assigned to each inlet channel 4 follows at a distance of only 50 mm, the width of each inlet 7a having an arc length of 100 mm and of each outlet 7b having an Arc length of 200 mm were chosen. It follows that only about 300 to 350 mm of the grinding chamber circumference is required for each mill segment which has an inlet channel 4 with an inlet 7a, a jacket segment surface 6 and an associated outlet channel 5 with an outlet 7b.

With the selected dimensions, the hammer mill can therefore be equipped with sixteen inlet channels 4 and sixteen outlet channels 5 on the circumference of the grinding chamber and can thus be divided into sixteen mill segments. Examples of numbers for the hole sizes on the outlet slide 9 are 1.5 mm for the screen area 8a and 3 mm for the screen area 8b. Instead of the free opening 8c, a third sieve with a very large hole size of z. B. 20 mm or more can be provided.

In the hammer mill shown, the coarse material, which is fed in vertically from above and fed radially into the grinding chamber 1 via an inlet channel 4, is hit and largely crushed by the hammers or beaters of the rotor 3 passing the inlet 7a, after which it is immediately crushed to the Outlet 7b of the associated outlet channel 5 arrives. Since the product produced in a certain mill segment has already been largely comminuted, it can almost completely pass through the free opening 8c or through a sieve 8a or 8b into the assigned outlet channel 5, so that the comminuted product is discharged and no further is dragged through the mill. As a result of the vertical feed and radial feed of the coarse material into the grinding chamber 1, the material is deflected by 90 in a horizontal movement path by the hammers or beaters of the rotor, which further promotes the comminution effect.

The comminuted product discharged via the outlet channels 5 of the hammer mill according to the invention can be fed to a suitable sieve device, it being possible to return sieve residues for the purpose of further comminution. The relatively simple arrangement of the hammer mill according to the invention offers various advantages, the following being mentioned: a considerable reduction in the power requirement for the comminution, a reduction in the wear costs and less heating of the material and a lower moisture removal during the comminution.

The dosing device shown schematically in FIGS. 4 and 5 is particularly suitable for the continuous feeding of material to be comminuted into a hammer mill according to the invention with a plurality of feed channels, each feed channel of the hammer mill having a corresponding dosing screw of a dosing device of the one in FIGS 5 shown type is assigned.

4 and 5 is arranged symmetrically about a vertical axis 20 and comprises two coaxial cells 21 and 22 for receiving two different goods, several dosing screws 23 arranged underneath and corresponding openings 24 and 25 in the bottom of the cells 21 or 22, which correspond to a first inlet or a second inlet of the metering screws 23. As can be seen in particular from FIG. 5, the metering screws 23 are arranged around the vertical axis 20 and extend from the openings 24 and 25 arranged under the cells 21 and 22, or from the corresponding first and second screw entries, to their outlet pipe 26 radially outwards.

The speed of the metering screws is controlled in a known manner by a control device, not shown, as a function of the required load on the hammer mill, so that the mill fed by this metering device with goods to be comminuted is operated with a uniform load.

The two cells 21 and 22 are used to hold two different goods, for example in two different grain sizes, which are sequentially gripped by the screws 23 via the openings 24 and 25 and fed to the mill. A first item located in the central cell 21 is detected with priority by the metering screws 23 via the inner openings 24 or the corresponding first screw entries and fed to the mill, a second item being borrowed continuously from the outer annular cell 22 via the outer ones Openings 25 or the corresponding second screw entries through the screws 23 are added in sufficient quantity to operate the mill with the desired load.

For example, the outlet channels 5 of the hammer mill can be connected to the central cell via a screening device (not shown)

21, respectively, said outer annular cell is provided 22 with fresh coarse material ^'.

Thanks to the special mode of operation of the described dosing device, the first good located in the central cell 21 is guaranteed absolute priority over the second good located in the outer annular cell 22, since this first good in the central cell 21 is inevitably via the inner openings 24 corresponding first screw entries through the metering screws 23 are first detected and only then is the second material from the outer annular cell

22 detected via the second screw entries corresponding to the outer openings 25 and fed to the hammer mill.

Thanks to such a mode of operation of the described dosing device, known problems arising during the grinding of different goods can be solved in an extremely simple manner with minimal work and simple technical aids.

Such an arrangement of the metering device is also possible with other controllable funding, eg. b. possible with chain conveyors, vibratory conveyors, etc., while the advantages explained above of the automatically controlled priority of dosing different goods are retained thanks to the very simple coaxial arrangement of the cells, which, as described, interact with several radially arranged dosing means via corresponding openings.

The number of coaxial cells and the associated metering devices can be chosen more or less freely as required. Technical applicability

The hammer mill according to the invention and the metering device can be used for different comminution work and bulk goods. They are particularly well suited for compound feed preparation, whereby an interaction between the hammer mill with several inlet channels and the metering device for the continuous metering of different goods by means of several metering devices offers special advantages.

Claims

1. Hammer mill with a grinding chamber, a rotor with hammers or beaters and a device for feeding in coarse material and discharging the comminuted product, characterized in that the grinding chamber (1) is arranged essentially horizontally, the rotor (3) A vertical axis is mounted, and that a number of inlet channels (4) with a corresponding inlet (7a) for feeding in coarse material to be shredded, and a number of outlet channels (5) with a corresponding outlet (7b) for the discharge of the crushed product from the grinding chamber, are arranged on the circumference of the grinding chamber (1) so that each inlet channel ^'(4) is associated with an inlet (7a), a corresponding outlet channel (5) with a daneben¬ lying outlet (7b), wherein the outlets (7b) are each distributed between two inlets (7a) on the circumference of the grinding chamber (1), so that the grinding chamber in the circumferential direction into a corresponding number of mill segments n is divided, which are each delimited by an inlet (7a) and a corresponding outlet (7b). 2. Hammer mill according to claim 1, characterized in that the inlets (7a) and the corresponding adjacent outlets (7b) are evenly distributed over the circumference of the grinding chamber (1).

3. Hammer mill according to claim 1, characterized in that the outlets (7b) are assigned several interchangeable sieves (8a, 8b) with different hole sizes, which can be brought into the corresponding outlet (7b) in the operative position.

4. Hammer mill according to claim 3, characterized in that the screens (8a, 8b) each on one, the corresponding

Outlet (7b) associated slide (9) are arranged.

5. Hammer mill according to one of claims 1 to 4, characterized in that the inlet channels (4) have guide means and are designed so that the coarse material can be fed to the rotor circumference in different horizontal planes. 6. Hammer mill according to claim 1, characterized in that a metering device for the continuous metering and supply of different bulk materials in several bulk material streams with adjustable feed for the continuous feeding of the feed channels (4) of the hammer mill with different to be crushed bulk materials is provided is that this metering device has at least two coaxial cells (21 or 22) which are arranged on a vertical axis (20), a first, central cell (21) being used to hold a first bulk material and by at least a second, outer annular cell (22) for receiving a second bulk material, and that a number of metering devices (23) are arranged radially under these cells (21, 22), each metering device (23) with the central cell ( 21) via a first unit corresponding to an opening (24) in the bottom of this cell (21) rode the dosing device (23) and with the second, outer, annular cell (22) via a second inlet of the dosing device (23) corresponding to an opening (25) in the bottom of this annular cell (22) stands so that the dosing devices' (23) remove the different bulk materials from the corresponding cells (21 or 22) via the first or the second inlet (24 or 25) during operation and at their outer end via an outlet pipe ( 26) to allow the continuous supply of appropriate feed channels (4) to the hammer mill with the bulk materials.

2. Hammer mill with a metering device according to claim 6, characterized in that the metering devices consist of radially arranged metering screws (23) with adjustable speed.