DE1936269A1 - Hammer mill - Google Patents

Description

■ »AIENVANWÄLTE

DIPL-ING. CURT WALLACH 1936 269

DIPL.-ING. GÜNTHER KOCH DR. TINO HAIBACH

8 MUNICH 2, l6. July 1969 UNSERZElCHENi 12129 - /

Nicholas Pora, Scarborough, Ontario, Canada. Hammer mill

The invention relates to a hammer mill with two separate grinding stages that work simultaneously and of a common one Shaft are driven.

There are known single-stage hammer mills in which the grinding stock is subjected to a striking movement by a large number of so-called hammers or is exposed to clubs that are mounted on a central rotor. With such mills one generally takes into account a high degree of wear and tear and the grinding process is not always of the same consistency, especially if a considerable one The aim is to reduce the particle size in one step.

In addition, it is necessary in such single-stage hammer mills, using a fine screen when a consistent finely ground product is required and that screen degrades obviously the flow rate of the material is considerable. As a result, the speed at which relatively coarse material can be ground is very limited and actual the discharge when such a fine screen is used is oily inadequate and inefficient. If you try increasing the input of the coarse material then this leads to bucket fellsi; lr4ig © B clogging of the umbrella "

3Ü4 / 1-321.

Besides, there's a hammer or a beater in a hammer mill which is suitable for grinding coarse material, not necessarily also suitable for grinding fine material and vice versa. As a result, maximum efficiency is seldom achieved.

One of the factors that affects the rate of flow of fine material through a fine screen is the flow of air that can be obtained through the mill. Such finely divided material seldom moves under the influence of gravity or even the centrifugal forces that occur within the mill. It has in fact finely ground as essential to the movement of considerable masses pulvrisierten ma- f terlals proven to provide a substantial flow of air so that the material loaded pulvrisierte faster and the screen is cleaned more rapidly.

Accordingly, it is an object of the invention to provide two hammer mills to be arranged on a common drive shaft and means to be provided, the continuously and automatically the half-milled Out convey from the first stage to the second stage, which significantly reduces wear and tear and a more uniform end product is obtained, which is reduced even further in terms of particle size.

The invention aims to avoid the disadvantages inherent in the previously known hammer mills and to create a two-stage hammer mill in which coarse grinding takes place in the first stage and fine grinding in the second stage. The two rotors of the hammer mill are arranged at a distance from one another on a common drive shaft and are mounted in a common housing, a partition being located between the two rotors. The first stage causes a relatively coarse reduction of the material through a relatively coarse screen and then the coarsely ground material is transferred around the septum to the second stage, in which the fine grinding takes place; and the fineFerniahlene uut through a fine screen hindarchtr.ttt>

09884/1321
Bathroom original

-V-

Significant amounts of air are entrained in the process and ' the use of a twin-stage rotor system has been shown to cause increased air flow due to centrifugal action. If extra heavy materials have to be ground * additional Air is supplied between the first and second stage and the distance between the rotors of the first and second stage increases the rotor shaft '• is enlarged and there is a larger passage for the flow of the coarsely ground parts after the second rotor stage causes.

Accordingly, it is an object of the invention to provide a two-stage Creating hammer mill with two rotors on a common shaft wherein the semi-milled product is continuously and automatically transferred from the first stage to the second stage, whereby the wear is reduced considerably and a more even one Starting product with an even further reduction in particle size is obtained. Further objects of the invention are to provide a two-stage hammer mill in which the half-milled Well from the first to the second stage by pneumatic means is convicted.

Another object of the invention is? To create a & weiötuf © nhara ~ mermühle in which the second stage is provided with a fan, through which. Air is continuously drawn from the erateß stage, whereby the half-milled Out is carried, which is then blown directly out of the outlet end of the mill, this ground end product can be discharged with the air mass by the fan in any way.

The two-stage hammer mill according to the invention is characterized by a two-stage rotor mill which continuously processes a ground product in two stages, the material being processed into a semi-ground product in the first stage, which is then processed into a finely ground end product in the second stage. According to the invention, the hammer mill has a first rotatable Harara mill stage, which converts the material to be ground into a semi-milled state,

901884/1321

BATH

a second rotary hammer mill stage coaxial with the first Stage passes, receives the semi-milled product and the particle size further reduced to the finely ground end product, a line between the output side of the first stage and the The entrance of the second stage is provided to convey the semi-ground out between the stages, and with a fan in the second Stage is arranged and air leads through the second stage and ensures that the grist can flow freely through 13.

An exemplary embodiment of the invention is described below with reference to the drawing. In the drawing show: Flg. 1 is a rare view, partly in section, of a two-stage. hammer mill according to the invention, designed for a large

Volume with a lighter and easy-to-grind Out, FIG. 2, on a larger scale, a view of the rotor of the second stage of the mill according to FIG.
Flg. 3 shows an axial view of the rotor of the second stage according to FIG. 2,

Fig. 4 On a larger scale, a single view of a hammer hammer,

5 shows a sectional view of a modified embodiment of the invention, particularly designed for an average output,
-Fig. 6 is a side view of a further embodiment of FIG

Invention, designed for great performance .. ι, ·

The hammer mill according Flg.l consists of a base 10 with bearings 11 which carry a shaft 12 which is rotated by unillustrated drive means "A stationary rotor housing 13 is supported by non-illustrated means and this is by a partition 14 divided into a first and a second rotor chamber, which are connected to one another via a circular central opening 55 in the partition wall. A material feed opening 16 communicates with the first rotor chamber via an opening 16a in the housing 1? in connection with each other and is equipped with an air flow regulating flap 17 which is adjustable therein.

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909884/1321

BATH ORIGINAL

A product outlet opening 18 communicates with the second rotor chamber Compound to remove the finely ground product.

The first rotor stage consists of a rotor 20, which preferably has three separate disks 21. The rotor 20 is on the shaft 12. held in place by suitable means, e.g. a retaining device. Longing and short hammer hammers 23 and 24, of which the edge in Flg.l is closed and which are shown in detail in FIG. 4 are arranged next to one another on bearing pins 25. It is clear that the Hammers 23 and 24 have different lengths, however both have approximately the shape shown in Figure 4 and they are alternately on corresponding bolts 25 at a distance from one another around the Rotor 20 arranged around. A total of about six such bolts 25 are provided, which in this preferred embodiment corresponding groups of hammers 23,24 carry. The ring-shaped Receiving wall 26 is secured within housing 10 closely adjacent to the path of rotor blades 23 and 24 as shown an annular screen 27 is between the wall member 26 and the Housing 13 carried to the semi-milled product from the rotor of the shield first stage, at the same time this material can emerge radially outward as soon as it passes through the mesh of the screen 27 Has. The housing 13 defines a substantially annular space, indicated generally at 28 and around the Screen 27 runs around so that the ground material can escape freely. The space 28 is in turn connected to a disk-shaped passage between the annular wall 26 and the Partition 14 is so that the air can flow freely and that semi-ground product along the path indicated by the arrows A through the opening 15 can reach the second stage.

The second stage of the hammer mill according to the invention consists of an arrangement which essentially corresponds to the first stage, but is somewhat larger than the first stage. It has a centrifugal fan to * \ m suck through the esSbe stage and then the product naeli d @ r "wide. Transfer stage and blow the ground end product out of the A ^ sIsS 18. The rotor of the second

908884/1321, ·.

SAOORfGJNAt

Stage and the centrifugal fan are carried by the same rotor 29, which is preferably provided with two separate disks j50 and 31 is provided. The disc 31 is equipped with a central annular opening 32 through which half or partially ground Can enter well from the first stage via the opening 15. In this preferred embodiment there are six separate fan blades 23 between the discs J50 and 31 and around them, attached radially as shown in FIGS. Additionally In this preferred embodiment, six groups of hammer hammers 34 and 35 are provided for these fan blades 33, the hammers 34 and 35 having different lengths, otherwise however, they have the same shape as can be seen in FIG. The blades 34 and 35 are next to each other alternately on retaining bolts 36 stored. An annular screen 37 is within the Housing 13 carried close to the circumferential path of the hammers 34 to allow the escape of grist. The housing 13 further defines a substantial annulus 38 extending outside the screen 37 and free flow of grist which is conveyed with the air through the screen 37 and to the outlet 18.

In operation wM the grist abandoned through the inlet 16 and enters the housing 13 on one side of the primary rotor 20, which rotates at high speed, so that the grinding stock through Centrifugal force flows outward between the hammer hammers 23 and 24 and is thrown by the hammer hammers 23 and 24 against the mesh screen and ground. The screen 27 is relative coarse in relation to the grist, so that only a partial grind takes place and then the semi-milled product can pass freely through the screen 27 into the annular space 28. Because both rotors 20 and 29 are mounted on a common shaft, the rotor 29 will rotate at the same speed as the rotor 20 and the fan blades 33 on the rotor 29 cause a relatively strong flow of air through the stage and after the outlet 18. The air that is expelled through this can of course only enter through the inlet opening 16 and consequently find it

909884/1321

BATH ORIGINAL

a relatively strong air flow through inlet 16 at all times and around the rotor 20 and through the screen 27 into the annular space 28 and from there through the opening 15 in the partition 14 after the outlet 18. This air flow carries with it half-ground Out which has emerged from the screen 27 into the space 28 and this grist is dureti the air in the direction of arrow A carried and enters through the annular opening between the rotor 20 and partition 14 hindureä and arrives at the central one axial opening 15 of the second stage. At this point occurs as a result the conveying effect of the fan blade 33, the air and entrained semi-ground products through the axial opening 32 in the Rotor disk 31 passes through it and is then driven by the combined action of centrifugal force and air flow between the blades 33 and the Hammersehiägera J4 and 35 siaoh thrown outside. In At this stage, the semi-milled product undergoes a further painstaking action between dcsa hammer blows 34 and 35 and the with fine machine-provided screen 37, after which, as soon as the good has passed through the fine-mesh screen 37 Annular space 38 enters and from there out of the housing 13 through the Outlet 18 is discharged «This material is discharged with the mass air flow, which also emerges from the vent.

According to a modification of the invention shown in FIG and intended for a medium weight grist, is the Design of the housing 13 and the partition 14 modified so that a somewhat freer product flow from the first stage to the second stage takes place and there is also an additional air inlet provided in the housing to ensure the introduction of additional air between the first and second stage.

As can be seen from Fig. 5, the housing has a grist inlet 16 and primary air inlet means 40, which have a feed of air at a point somewhat closer to the first stage «! than in the embodiment according to Fig.i the Case was. This ensures that the unmilled Product is well ventilated and can flow freely. the

909884/1321

The configuration of the first and second stage rotors 20 and 29 is essentially the same as that of the embodiment according to Fig.l with the difference that the rotors a little further on the drive shaft 12 are distanced, so that a freer. * Air flow can take place and semi-ground material can be transferred from the first to the second stage. Also is a partition 41 is provided, which corresponds to the partition 1.4 according to FIG. 1 corresponds. This partition wall 41 has the general shape of a frustoconical saucer and is equipped with lips 42 which delimit the through opening 15. The lips 42 open directly after the central axial space around the rotor 29, which ensures that the air and semi-ground material sucked in directly after the central axial area

* flows and is completely married there. The annular space 28 is located around the screen 27 and there the good in this embodiment is ground a little more heavily, the main part of this half-ground material falls under the influence of gravity into the lower part Area of the annular space 28. In order to ensure a free and continuous flow of air and entrained semi-ground material from the annular space 28, a secondary air inlet 43 is in the Proximity to the lower part of the ring space 28 so that additional air is introduced into the system and that additional air is passed through the fan blade 33 and the rotor 29 * sucked in * As with the embodiment according to Flg.l, the screen is 37 of the second stage slightly larger in diameter and in the Width than the screen 27 of the first stage, creating a larger Screen surface is available for the passage of finely divided material, so that clogging of the screen to any Place is prevented. At a slightly different point, a product outlet 18 is provided through which the finely ground material is discharged.

Due to the design according to Fig. 4, it is a little heavier Well and the half-ground material from the first stage a slightly larger passage for a freer air flow old entrained half-ground material is available, whereby at any time

90988-4 / 13 21

BADORfGlNAL

a maximum throughput is guaranteed.

Another embodiment of the invention is shown in FIG. This hammer mill shown here is for higher performance intended and for an even heavier grist. In this case the housing 13 is separated into two by a partition 50 closed chambers divided and the rotors 20 and 29 are even more distant along the drive shaft 13, while otherwise essentially the same training as provided in the embodiment according to Pig.l and 5. In the embodiment of Figure 6 extends Screen 27 of the primary stage between the housing wall 13 and the Partition wall 50 and thus completely encloses the primary rotor 20; the annular space 28, which runs around the outside of the screen 27, is at its lower end with the product discharge channel 51 in connection. The channel 51 is at the lower end of the housing 13, as almost all heavy, semi-milled products quickly reach the lower section under the influence of gravity. As in the embodiment according to FIG. 5, a primary inlet 40 is provided in the vicinity of the ground material input 16, which ensures that the unground material can freely enter the housing 13 can reach one side of the rotor 20.

A secondary air inlet 52 communicates with the channel 51 and creates the possibility that additional air can enter and transfer the half-grain material through the opening 32 upwards and into the central region of the rotor 29 of the second stage. An additional partition 53 essentially closes off the rotor 29 of the second stage and the screen 37 of the secondary stage extends between the rare wall of the housing 13 and the partition 53. A product outlet 18 communicates with the annular space 38 in order to discharge the finely ground material.

When DL® Hamoruahlt is according Pig.6 in operation, the unground © P ^ Mukt is introduced into the product inlet 16 and flows under ¹ ü®m llnfluß of gravity through the opening 16a

• A-909884/1321

CLASS BAD ORIGINAL

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of the housing 13 and in the central area of the rotor 20, where the ground material passes through centrifugal force to the outside between the hammer hammers 23 and 24 and is processed into a semi-ground product in connection with the screen, 2J. As can be seen, the semi-milled product passes through the screen 27 and is withdrawn downwards to the lower region in the channel 51 by air drawn in through the primary air inlet 40 and the grist inlet 16 under the influence of the fan blades 33 of the second stage rotor . At this point, additional air is continuously sucked in through the blower blades 33 via the secondary air inlet 52 and this ensures that the entire semi-milled product is completely sucked off and. is conveyed upwards through the channel 51 and the opening 15 in the partition 53 and through the opening 32 in the disk 31 of the rotor 29 to the central area of the rotor 29, where the out is thrown by the centrifugal force and through the hammer striker 34, 35 is ground against the screen 37. The end product then exits via the annulus 38 and the product outlet 18.

It has been found that the performance requirements of the system for fine grinding relatively coarse material for a given Product output can be significantly reduced compared to the performance requirements of known systems and also will the wear of the moving parts by the invention is considerable reduced and also the de fahr is reduced that an undesirable Overheating of the ground material occurs during grinding.

Claims

909884/1321

BATH ORIGINAL

Claims (10)

Patent claims: 1 .. 'Two-stage rotary hammer mill for continuous grinding of a ""' product in two stages «whereby in a first stage the Product is subjected to a predetermined degree of grinding, while the semi-ground product is added in the second stage a finely ground end product is processed, characterized in that, that a first rotary hammer & h. stage (20,21,23 * 24) is provided is, through which the product is converted into the semi-ground state, that a second rotary hammer grinding stage (29,30,31,34,55) is provided coaxially to the first stage to which the semi-milled product is fed and which this a fine milling subjects that a line guide (29) between the output the first stage and the entrance of the second stage is provided to the semi-ground material from the one stage after the other, and that a rotating fan (33) is provided in the second stage, which works together with this and sucks air through the second stage and in free flow of the product guaranteed. 2. Hammer mill according to claim 1,
characterized, that it has a common housing for the first and second stages, that a drive shaft (12) extends through the housing, that a rotor (20 or 21) of the first or second stage are arranged on the drive shaft at a distance from one another that a partition (14) is provided in the housing, which is extends between the first and second rotor stages, and that an axial opening (15) in the septum around the drive shaft around half-milled material from the first Stage to transfer after the second stage. 3. Hammer mill according to claim 1,
characterized, that an annular product outlet space (28) around the first hammer mill stage is laid around that an inlet port (32) In the 909884/1321 ^{; 1} ^ ¹ ßAD ORIGINAL second. Stage around the common axis of the first and second Stage is arranged around, and that a product line guide (29) extends between the annulus and the second stage inlet port. 4. hammer mill according to claim 1,
■ characterized in that the second stage has at least two spaced apart disks (30,31) which are arranged on a central hub (29), and that the hammers (34,35) are pivotably mounted between the disks, and that a fan (33) is mounted between the discs. 5 hammer mill according to claim 4, characterized in that an annular product inlet opening (32) at least in one of the disks (31) is provided to convey semi-ground material around the hub, the material then between enters the slices to be ground. 6. hammer mill according to claim 1, characterized in that a common housing (13) for the first and second stage ... it is provided that a product inlet opening (l6) with the The first stage is related to unground product to be able to introduce on one side, and that a primary air inlet 17.40) is assigned to this product inlet opening. 7 Chamber mill according to Claim 6, characterized, that a secondary air inlet (43,52) with the line management between the stages is in communication to provide additional air to be introduced between the first and second stage. 909884/1321 BATH ORIGINAL 8. Hammer mill na © h claim 1 “. characterized in that jsd © Stuf® has at least two disks (21,50,51) which are mounted at a distance from one another on a hub (20,29), that hammer strikers (25 * 24 * 54 _£ 55) can swing between these disks and are rotatably mounted together, and that annular screens (27, 57) are arranged around the hammer strikers at a distance from them. 9 · hammer mill according to claim l _s characterized in that ^{e has} a common housing (15) for the first and second stages, that a partition (44) is arranged between the first and second stages, that the partition is designed in the form of a flat cone, the. The apex is directed towards the second stage, and that a circular product opening (42) is arranged in the septum around the apex of the cone. 10. H _ammern rtihie according to claim 1, characterized in that an annular product outlet space (28) is arranged around the first® stage and that © in the air inlet (45 _# §2) communicates with this annular space (28) to allow additional air to be drawn off by the fan. 909884/1321