CA2229957A1 - Hammer mill or hammer crusher - Google Patents

Abstract

The invention relates to a hammer mill or hammer crusher which is provided with two rotors 2, 3 inside the housing 1. The rotors are essentially encircled by grinding paths 13, which are laterally retractable from the housing in an essentially horizontal direction.
Provision is thereby made for the section 23 of the grinding path located behind the vertical sectional plane through the rotor axis and projecting upwards from the lowest part of each rotor to be tilted downwards on retraction of the grinding path 13 and thus freeing this part from the rotor. According to the invention, curved flanges 24, 25 are provided on the downwardly tiltable section, which are supported by a counter-support 30.

Description

CA 022299~7 1998-02-20 Hammer mill or hammer crusher Description The invention relates to a h,..~....e~ mill or hA..,...el crusher equipped with at least one rotor fitt~ d with il, ~a~in~ implements and at least one grate or milling unit as counter-acting implement allotted to the rotor or to each rotor and at least partially encircling the rotor andL comprising impact bars, grate bars or screens and corresponding rel~ ing side o walls, the said grate or milling unit being provided with a guide device having a plurality of roller pairs and rails which allows its movement in an ec.~enti~lly horizontal direction for withtlrawal of the grate or milling unit from the housing, with a device to permit sufficient lowering of that section of the grate or milling unit which is designed to tilt downwards and which, when viewed from the direction of retraction, lies behind the vertical sectional plane passing through the rotor axis and projects upwardly from the lowest part of the rotor so that, on withdrawal of the grate or milling unit from the rotor, the said tiltable section can swing downwards on hinges connecting it to the fixed part of the grate or milling unit and pass freely underneath the bottom of the rotor.

20 In such types of mill or crusher, the crushing process is effected through impact by the rapidly ,ota~il g hammers in conjunclion with counter-acting implements. Such m~chines are designed with one or two rotors as single- or double-sha~ h~mmer mills or crushers, and have a high crushing efflciency. The counter-acting implements encircle the rotors and are only interrupted by the material inlet. Depending on the properties of the feed 25 material and the degree of crushing required, the counter-acting implements are provided as screems, milling grates or grinding paths, or a colllbinalion of all these implements.
The crus]hed material is discharged pne -m~tically from the mill or crusher via the screens or grates; the material outlet can be a l~lged underneath or above the rotor(s). In order to achieve maximum capacity and crushing efficiency, each rotor is enclosed extensively 30 by the counter-acting implements.

CA 022299~7 1998-02-20 Such counter-acting implements are subjected to high wear and must be easily replaceable. In the case of the afore-mentioned impact or h~mmer mills according to DE-PS 472 243, the screen unit provided underneath the rotor is equipped with a guide device to permit its holiGollLal movement and which colll~lises pairs of rollers and s collesponding rails to accommodate them. In order that the section of the screen unit proje~,lillg upwards from the lowermost point of the rotor behind the vertical sectional plane passing through the rotor axis can pass freely underneath the rotor when the screen unit is withdrawn from the crusher housing, it is designed to tilt downwards on hinged )oints.

For this purpose, the downwardly-tiltable section is movably connected by means of an axle to the carriage-type frame which accommodates the lelainel~ or side bars carrying the screens. The axle firmly connecte~ to the downwardly-tiltable section features a lever which is in er~ement with a tie-rod, the end of which is designed as a threaded spindle.
By means of a cranking handle ~tt~ched to the threaded spindle, the lever can be pivoted and the 1:iltable screen section tilted downwards. This design is, however, costly, and in addition to the fact that the movable parts, such as lever, tie-rod and in particular the threaded spindle are located in the material flow and subjected to fouling and wear, actuation of the crank handle can only be effected m~ml~lly and is thus onerous.20 FurthGIl,lol~;, this manual actuation cannot be utilised in larger hammer mills or crushers.

DE 32 15 882 A1 refers to a h~ er crusher in which the grate urits underneath the rotor are equipped with a guide device which allows essenti~lly horizontal movement, said device comprising pairs of rollers and rails to accommodate them. On retraction of 2s the grate units from the crusher housine in order to permit free movement undemeath the rotor of the grate section which is located behind the vertical sectional plane passing through the rotor axis and which projects upwardly from the lowermost point of the rotor, the rails are arranged in a sloping manner so that the grate units are lowered during the retraction movement.

...13 CA 022299~7 1998-02-20 In order l:o achieve this, however, it is necess~. y for the rails for the front and rear rollers to be arr~nged in an offset manner, so that a total of four rails is required per grate unit, or the design of the outer rollers must be executed adjustably by means of an additional me~h~ni~m Additionally, provision is made for the crushing pressure to be absorbed by a 5 carrier tube onto which the particular grate unit with its grate side plates has to be seated. This design is complicated and thus expensive, as there has to be an exact and precise matçhine of the rails with their slopes to the rollers as well as the grate units to the corresponding carrier tube and other housing parts. Moreover, in addition to the grates, which of course can also be designed as grinding paths, the double-shaft harnmer 10 crusher described therein is provided centrally with an anvil, which is only separately eY~h~ngeable with some effort.

The same applies to the h~mmer crusher accoldillg to DE 21 40 026 A1. It differs from the present state of terhnology des~,lil,cd above in that the retractable frame with the 5 associated housing section, reception side plates and grate, which is allotted to each rotor is mounted on di~lelll rails. In the outer zone, the rails are embedded in the foundation which supports the h~mmer crusher and carry the outer rollers affixed to the retractable housing section. Moreover, the side plates connected to the housing section are themselves designed as rails which ride on pairs of rollers laterally affixed to the 20 housing. In addition, outer and inner counter-supports are provided for the housing and grate. Furthermore, only a small section of the inner-facing part of the grate is in interaction with the rotor, so that the grate does not need or hardly needs to be lowered.
The hammers are movably att~ched to the rotor, so that they are free to avoid any collision. With this design, the inside grate (or in the case of double-rotor crushers, the 2s grates al ~ anged near to the centre) have to be changed separately.

The aim of the invention is to avoid the disadvantages of the present state of technology described~ above and to present a h~mmer rnill or h~ crusher with counter-actingimplements which enclose the particular rotor to the m~im~lm extent for the purpose of 30 increasing the comminlltion effect, whereby all grinding path, milling grate or screen .../4 CA 022299~7 1998-02-20 parts a~ ged underneath the rotor(s) are easily accecsible and hence easily replaceable.
At the same time, in respect of the fabrication process, the necess~ry m~tr.hine of the components should be easy to execute, leading to reduced costs.

s This problem is solved in the following l.lamle-, the downward}y-tiltable section of each grate or milling unit features at least one curved flange, by means of which, when the grate or milling unit is advanced and runs against a counter-support, the tiltable section is pushed upwards into the operational position. With this measure, it is possible to move the tiltable section located behind the rotor into the operational position by simply lo advancing the grate or milling unit into the housing.

This perrnits designs in which the milling units enclose each rotor extensively, so that in double-n~tor crushers or mills, for example, counter-acting implements such as anvils, etc. securely affixed to the housing between the rotors are superfluous. Since the tiltable 15 section of the grate or milling unit no longer projects above the lowest point of the associated rotor, the grate or milling unit can be retracted without hindrance.

It is a fa,ct that DE-AS 19 30 038 reveals a double-rotor hA.. ~er crusher, in which the rotors are enclosed by grates, whereby the grates are designed as whole units which are 20 tiltable downwards and outwards. The side housing parts are of multi-tiltable design by means of hinged joints to permit access to the rotors from above. At the same time, however., access to the grates is difficult and they are only exchangeable as a whole unit, resulting is very high m~int~n~nce costs.

2s A further imple..~ ;on of the invention is the provision of rollers on the counter-support to guide the curved flanges of each grate or milling unit, reducine the effort required to advance and retract the grate or milling unit.

Also innovative in the double-rotor design is the fact that, when the tiltable sections of 30 the grate or milling unit are in the operational position, they are designed to support each ...l5 CA 022299~7 1998-02-20 other. This relieves grinding pressure on the counter-support, so that the latter and the rollers provided thereto can be of a lighter construction.

The drawing illustrates an embodiment of the invenhon as follows:

Fig. 1 is a lonf~;itu-lin~l view through a h~ r mill acco,dil-g to the invention, which can also be design~ted as a hamrner crusher o Fig. 2 is a large-scale part-section view of the tiltable sections of the grate or rnilling units Fig. 3 is a large-scale part-section view of the tiltable sections of the partially-retracted grate or milling units As Fig. I shows, the h~mmer mill features a housinE 1, h,l~lged in which are two rotors 2, 3 fitted with a number of h~ .e;~ 4 which are pivotably-mounted in the rotors on bolts 5. l'he h~.. e mill features a material inlet 6 and an outlet 7 for the crushed/milled material, which in the example shown is pnel~m~tic~lly discharged upwards with the aid of a flow of air. During operation, the rotors turn at a high speed in the direction of the arrows x around axes 8, 9. Whereas the material inlet 6 is open, material outlet 7 is provided with grate bars 10, which enclose the rotor 3 in the form of a circular seEm~nt and only allow passage of correspondingly commim-ted material through the bar gaps.
2s The other sectors of grinding chambers 11, 12 are closed by grinding paths 13 made up of impacl: bars 14 alternately separated by spacer bars 15.

Such grillding paths are provided at the top between the two rotors 2, 3 where they are more easily acces~ikle, but also underneath the rotors as well, in which location, they can only be serviced and the impact or spacer bars exchanged if they are first moved into a ...16 . .
2~ 2~98 13: 36 --HRZE~1RG 8. EPR - ~ 61323284413 NUt1124 ;~32 position where they are rs~ ble to ~ nce ~.~llnel. To do this, the lower ths ~re a~ched to ~ide walls 16, 17 which can be re~cted from the ho~
I and w~ch eac!l r~terr~ y to~gcthcr with a hou~ wall 18, 19 form a ' ~ B closure.
The u"d~:. ~cs of the side phtes are pro~ided with pai~ of roUers 20, which , p~ I on s rails 21, 22 thc grinding units thus forlr~d. The grinding un ts c~ be moved in and out of the mill hou~ng 1 by means of :~*'e movîng devicos (not illw~ ), such as hydr~ulic ~- d ~ r piston units.

The inna-f~cing part 23 of each ~; ~ ~ pa~ 13 pro3~cts u~d~ nd t~e lowcst 10 point of the ~~ ~cioted rotor 2, 3 by a cons de~ble amount. In order that each milling unit can be r~ d from the l ol~sinc 1 with the ~..~ g path 13, part 23 of the milling un~t which preje ~c upwardly ofthe fixed rotor parts is designed so that it is d~,.. ~y tiltable. As can be ~een in p_rticul. r in Pig. 2, this p~rt GC~ 'I8eS c~lrvcd flanges 24, 25 in psirs onto which the impact bars 14 and spacers 15 sre secured by means of r_I~.~s 26. ~he flanges 24, 25 are tiltably r ~ ed to the side walls 16, 17 by hingcd joints 27, 28.

In the centre of ~he mill ho~leine 1 at the bottom between the houci~ walls is provided a be~m 29 on which is ~ltu.ge~ a counter-suppon 30 which illt~ ~tc with the curvedflsnges 24, 25. For the purpose of f~cilit~i~ the Illo~ t opc.~ons and to guidc the flanges 2!4, 251 the counter-support 30 is fitted with rollers 31, 32. The CC..l~ ~o~d,ng c~ e~l;Qns bet~veen the side walls 16, 17 and the sides of the fl~ng~ 24, 25 facing them are made by cross-bars 33, 34 and 35, 36. The tiltable section of each milling unit ;s provided at its top end 37 with bars 3~ and 3g t~s~e~i~ely, ~llw~ both bars 38, 39 25 touch snd ~UppOl ~ each other snd hence the tiltable sGctiQns of the milling units.

As shown in Fig. 3, on ~k~l;on of the milling uns~s, the W Fved flanges 24, 25 ride on the rollers 31, 32 of the cour~er-support 30, during which, tog~ .e with the n -o~
parts 23 tha~ tilt downwards ~r enough to enable the whole milling unit to be moved 30 ho~o..I~lly to the outside unde...,e~th the rotor 2, 3 fi.l ~id above it.
...J7

Claims (3)

1. A hammer mill or hammer crusher equipped with at least one rotor fitted with impacting implements and at least one grate or milling unit as counter-acting implement allotted to the rotor or to each rotor and at least partially encircling the rotor and comprising impact bars, grate bars or screens and corresponding retaining side walls, the said grate or milling unit being provided with a guidedevice having a plurality of roller pairs and rails which allows its movement in an essentially horizontal direction for withdrawal of the grate or milling unit from the housing, with a device to permit sufficient lowering of that section of the grate or milling unit which is designed to tilt downwards and which, when viewed from the direction of retraction, lies behind the vertical sectional plane passing through the rotor axis and projects upwardly from the lowest part of the rotor so that, on withdrawal of the grate or milling unit from the rotor, the said tiltable section can swing downwards on hinges connecting it to the fixed part of the grate or milling unit and pass freely underneath the bottom of the rotor, characterised in that the downwardly tiltable section (23) of each grate or milling unit (13, 16/17, 18/19, 20) features at least one curved flange (24, 25), with which the tiltable section can be pressed upwards into the operational position by running against a counter-support (30) when the grate or milling unit (13, 16/17, 18/19, 20) is advanced.

2. A hammer mill or hammer crusher according to claim 1, characterised by rollers (31,32) on the counter-support (30) to guide the curved flanges (24, 25).

3 A hammer mill or hammer crusher according to claim 1, characterised in that, in the double-rotor design, the downwardly tiltable sections (23) of the grate or milling unit (13, 16/17, 18/19, 20) are designed to support each other in the operational position.

.../8