GB1569093A

GB1569093A - Grinder for bulk materials

Info

Publication number: GB1569093A
Application number: GB1304778A
Authority: GB
Original assignee: V N I KONSTRUKTTEKHNOLOG I MAS
Current assignee: V N I KONSTRUKTTEKHNOLOG I MAS
Priority date: 1978-04-04
Filing date: 1978-04-04
Publication date: 1980-06-11

Description

(54) GRINDER FOR BULK MATERIALS (71) We, VSESOJUZNY NAucHN > Is- SLEDOVATELSKY KONSTRUKTORSKO-TEKH- NOLOGICHESKY INSTITUT Po MASHINAM DLYA KOMPLEZNOI MEKHANISATISII I Avlo- MATIZATSII ZHIVOTNOVODCHESKIKH FERM "VNII2MIVMASH", an enterprise organised and existing under the laws of the Union of Soviet Socialist Republics (U.S.S.R.), of ulitsa Shamrylo, 23, Kiev, USSR, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: - The present invention relates to the production equipment designed for crushing and grinding various materials and, in particular, to the grinders for bulk materials and can be used for grinding corn and other ingredients of mixed fodder, soft minerals such as asbestos, talk, and the like.

The present invention contemplates the provision of a grinder for bulk materials, comprising a housing with an upper disk mounted therein and having a charging aperture in its central portion, cutting ribs disposed on the lower face of the upper disk and oriented from the centre towards the periphery, projections disposed on the lower face of said upper disk and running from the peripheral ends of the cutting ribs to the opposite ends of the adjacent cutting ribs so as to form a closed zigzag contour, therewith a lower disk mounted coaxially with the upper one and provided with cutting ribs on its upper face, a rotation drive connected to, at least, one of the disks.

With this constructional arrangement of the upper disk, the bulk material gets into a space confined by the ribs and projections, and its particles after having been cut once only, by the interacting cutting ribs, are forced from the closed zigzag contour and thrown by the centrifugal force out from the space between the disks and then removed beyond the grinder. Size of the ground material is defined by the height of the cutting ribs of the lower disk and thus practically is the same for all the fractions of the final product. Immediate discharge of the fractions already ground prevents them from being repeatedly subjected to the mechanical action and frictional abrasion resulting in the formation of dustlike particles.That each particle is subjected once only to the mechanical action permits the technological energy to be utilized more rationally, while freedom from the dust particles on the one hand brings down the loss of the material being treated, and on the other hand minimizes dust content in the production premises which in turn makes the additional equipment for air filtering and dust collecting unnecessary, and improves the grinder efficiency owing to the shortened idle time during its routine cleaning.

It is also possible to construct a grinder for bulk materials as a multistage one in which the projections and cutting ribs are arranged to form on the upper disk several closed concentric zigzag contours, while the surface of the lower disk is made stepped with the same number of the concentric circular steps the height of which gradually decreases from the center towards the periphery of the disk.

Such an embodiment of the invention, taking into account the above advantages, permits relatively large particles of the bulk material to be ground by stages to produce the desired size. At the same time this makes it possible to replace a multistage process line consisting of several disk grinders by one multistage grinder ensuring practically the same productivity of the process, and lowering the consumption of energy and the weight and size of the equipment.

To obtain a quality product it is most expedient that in the above embodiment of the multistage grinder the width of each step of the lower disk be equal to the maximum distance between the adjacent zigzag contours disposed over said step and formed by the cutting ribs and projections of the upper disk.

It is further expedient to make the cutting ribs of the upper and lower disks in the form of plate blades mounted in the slots thereof so that the cutting ribs of the upper disk extend above the projections thereof. This prevents damage to the projections by the hard particles in the basic material and permits the worn out and damaged parts to be replaced without change of the disks, which increases the service life of the grinder.

It will be appreciated that in the above one-stage and multistage grinder embodiment the plate blades are mounted in the slots of the upper and lower disks to permit the height of the cutting ribs to be varied for the purpose of adjustment.

The most advantageous for the purpose of the simultaneous adjustment of the height of all the cutting ribs is the embodiment of the invention in which there are provided plates having plate blades, connected to the upper and lower disks by means of rods with variable length.

The desired distance between said plates and disks and hence the height of the cutting ribs of the upper and lower disks is achieved through varying the length of the rods, the cutting edges of the ribs of each disk being kept in the same plane.

The most simple and reliable embodiment of the above example is the construction of arrangement in which the plate blades of the upper disk are fastened to the plate by means of rods having lugs on their ends, said lugs being set in the orifices of said plate blades and fixed by means of pins resting upon the lower face of the plate and the upper edges of the plate blades, while the plate blades of the lower disk are mounted in the open slots and rest at their lower edges upon the surface of the plate To enable rapid replacement of the worn out or damaged cutting ribs of the lower disk, it is advisable to make their plate blades trapezoidal and the walls of the slots, on the periphery of the lower disk, inclined so as to have the centre of gravity of each plate blade below the line of contact thereof with the wall of the slot.With such a constructional arrangement the blades are simply positioned in the slots in which they are secured by the centrifugal force produced by the rotation of the lower disk.

It is technically expedient to make the upper plate in the form of a disk screwedin into the cylindrical shell of the body of the grinder and fixed by means of an insert positioned in the open radial orifice in the wall of the shell, secured by a screw and having on its one end a thread the pitch and profile of which coincide with the respective parameters of the thread in the shell. Such an arrangement prevents the upper disk from slippage, misalignment and damage to the cutting ribs.

The above-mentioned and other advantages of this invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein: Fig. 1, is a centre-line elevation of the bulk material grinder, according to the invention; Fig. 2 is a sectional view of the bulk material grinder, taken along the line II-II in Fig. 1 to illustrate the arrangement and orientation of the cutting ribs and projections on the lower face of the upper disk, according to the invention; Fig 3 is a sectional view of grinder taken along the lines III-III in Fig. 1 to illustrate the orientation of the cutting ribs on the upper face of the lower disk, according to the invention;; Fig. 4 is a fragmentary sectional view of the upper and lower disk with cutting ribs and projections taken along the line IV-IV in Fig. 1, according to the invention; Fig. 5 is a vertical centreline section of the modification of the stage grinder, according to the invention; Fig. 6 illustrates the modification of the grinder taken along the line VI-VI in Fig.

5, a fragmentary view of the lower face of the upper disk, showing the arrangement and orientation of the projections and cutting ribs, according to the invention; Fig. 7 illustrates the modification of the grinder of Fig. 5, as viewed along the line VII-VII in Fig. 5 to show the upper face of the lower disk and illustrate the orientation of the cutting ribs and the stepped surface, according to the invention; Fig. 8 is a fragmentary view of the upper and lower disks, taken along the line VTII VIII in Fig. 5, according to the invention; Fig 9 is a fragmentary view of the lower disk and impeller, taken along the line IX-IX in Fig. 7, according to the invention; Fig. 10 illustrates the modification of the grinder with the removable cutting ribs, vertical center-line section, according to the invention; ; Fig. 11 is a fragmentary view of the upper and lower disks with plates and plate blades, taken along the line XI-XI in Fig. 10, according to the invention; Fig. 12 is a fragmentary view of the upper disk with the connecting rods of the plate and plate blades taken along the line XIT-XII in Fig. 15, according to the invention; Fig. 13 is a fragmentary view of the upper disk with the plate and rods fixing the plate blade, taken along the line XIII XIII in Fig. 12, according to the invention; Fig. 14 illustrates fastening of the plate blade on the upper disk, taken along the line XIV-XIV in Fig. 13, according to the invention; Fig. 15 illustrates the lower face of the upper disk, taken along the line XV-XV in Fig. 10, according to the invention;; Fig. 16 is a fragmentary view of the lower disk with the plate and plate blade, taken along the line XVI-XVI in Fig. II, according to the invention; Fig. 17 illustrates fastening of the plate of the upper disk to the cylindrical shell of the body of the grinder in Fig. 10, according to the invention; Fig. 18 is a perspective view of the fixing insert, according to the invention; and Fig. 19 illustrates the modification of the grinder with the conical disks, vertical centreline section, according to the invention.

A grinder for the bulk materials, according to the invention, as shown in Fig. 1, comprises a housing 1 which accommodates an upper disk 2 and a lower disk 3, and a rotation drive 4 connected to at least one of said disks. On the lower face of the upper disk 2 there are provided cutting ribs 5 while on the upper face of the lower disk 3 there are provided cutting ribs 6.

The upper disk 2 and the lower disk 3 are mounted coaxially in the housing 1. In the central portion of the upper disk 2 there is a charging aperture 7. On the periphery of the housing 1 there are provided grooves 8 for removal of the ground material. According to this embodiment of the invention the rotation drive 4 is connected, by means of a shaft 9 and a key 10, to the lower disk 3. Under the charging aperture 7 there is an impeller 11 fixedly mounted on the rotatable disk 3.

The upper disk 2 is fixedly secured to the housing 1 of the grinder.

In the embodiment disclosed in Fig. 2, on the lower face of the upper disk 2 there are provided projections 12. The cutting ribs 5 of the upper disk 2 are substantially oriented from the centre towards the periphery. Each projection 12 runs from the peripheral end of the cutting rib to the opposite end of the adjacent cutting rib so that the projections 12 and the cutting ribs 5 form, according to the invention, a closed zigzag contour. The closed zigzag contour confines, on the inside, channels 13 for the basic material to pass from the charging aperture 7 into the grinding zone, and, on the outside, channels 14, for removal of the ground material to the periphery of the disk and to the grooves 8.

The cutting ribs 6 of the disk 3 are oriented at an angle to the radius and, according to this modification, have a bent shape as shown in Fig. 3. At their intersection the cutting ribs 5 and cutting ribs 6 form an angle which must not exceed two times the angle of friction between the material being ground and the blades 5 and 6. The size of this angle is determined depending on the material to be ground by the grinder constituting the present invention.

With such relation between the angles of setting of the cutting ribs 5 and 6, the grinding of the bulk material is effected, mainly, owing to the slide cutting deformation between said blades.

As shown in Fig. 4 of the drawing, the height of the cutting ribs 5 and projections 12 of the upper disk 2 exceeds the height of the cutting ribs 6 of the lower disk 3.

In this modification of the embodiment of the invention the cutting ribs 5 and projections 12 are made integral with the upper disk 2 and the cutting ribs 6 are made integral with the lower disk 3.

Fig. 5 of the drawings discloses a modification of an embodiment of the grinder, according to the invention, designed for a state grinding of the bulk material. According to this modification the face 14 of the lower disk 3 has a stepped shape.

While the projection 12 and the cutting ribs 5 form several closed concentric zigzag contours 15, 16 and 17, as shown in Fig. 6 of the drawings.

Fig. 7 of the accompanying drawings represents the upper face 14 of the lower disk 3. As can be seen the number of the steps on the surface thereof corresponds to the number of stages of grinding, i.e. to the number of the closed concentric zigzag contours 15, 16, 17.

The height of the steps on the face 14 of the lower disk 3 gradually decreases from the centre towards the periphery of the disk, as shown in Figs. 5 and 8.

The width of each concentric step 18 of the disk 3, according to the invention, is equal to the maximum distance between the zigzag contours 16 and 17 disposed there over and is formed by the cutting ribs 5 and the projections 12 of the upper disk 2, as can be seen from Fig. 8 of the drawings.

It is expedient that a transition 19 between the adjacent concentric steps 18, 20 and 18, 21, etc. be smooth and made in the form of a bevel, as shown in Fig. 9 of the accompanying drawings.

The most expedient embodiment of the invention, ensuring a longer service life of the grinder, is shown in Fig. 10.

According to this embodiment of the invention of the cutting ribs 5 and 6 of the upper and lower disks 2 and 3 respectively, are made in the form of plate blades 22 and 23. The plate blades 22 are mounted in slots 24 of the upper disk 2, as shown in Fig. II of the drawings.

The plate blades 23 are mounted in slots 25 of the lower disk 3.

The height of the cutting ribs 5 of the upper disk 2, including the protruding portion of the blade 22, exceeds the height of the projections 12.

The plate blades 22 and 23 are mounted in the slots 24 and 25 of the upper and lower disks 2 and 3, respectively so as to permit the height of the protruding portion of said plate blades to be varied, thus enabling the height of the cutting ribs 5 and 6 to be adjusted. The slots 24 and 25 are inclined so that the plate blades 22 and 23 mounted therein are disposed at an angle to the surface of the disks 2 and 3, respectively. Such an arrangement allows the energy consumption per unit of the product to be cut down and ensures self-sharpening of the plate blades 22 and 23 in case they are made bimetallic.

For adjustment of the height of the cutting ribs 5 and 6, the upper and lower disks 2 and 3 have plates 28 and 29 connected thereto, by means of rods 26 and 27, as shown in Figs. 10, 11 and 12. The rods 26 and 27 are made so that their length can be varied to enable the distance between the disks 2, 3 and plates 28, 29 respectively, to be adjusted. As can be seen from Figs.

10 and 12 the rods 26 and 27 are made in the form of a pin threaded-in into the disks 2 and 3. Said rods 26 and 27 are fixed on the side of the plates 28 and 29 by means of nuts 30 and 31. The plates 28 and 29 carry the plate blades 22 and 23, respectively. As can be seen from Fig. 12, the plate blades 22 of the upper disk 2 are connected to the plates 28 by means of rods 32 having lugs 33 on their ends, said lugs 33 being set in openings 34 of the plate blades 22, as shown in Figs. 12 and 13. The rods 32 have at their opposite ends threads and are secured to the plate 28 by means of nuts 35.

The plate blades 22 are fixed by means of pins 36 resting upon the lower face of the plate 28 and upper edges of the plate blades 22 as shown in Figs. 13 and 14.

As shown in Fig. 15 of the drawings, the orientation of the cutting ribs 5 of the upper disk 2, when made in the form of the plate blades 22, approximates a radial one.

The plate blades 23 of the lower disk 3, as shown in Figs. 10, 11, 16 are mounted in the open slots 25 of the lower disk 3 and rest with their lower edges upon the surface 37 of the plate 29. Said plate blades 23, as can be distinctly seen from Fig. 16, have a trapezoidal shape, while the walls of the open slots 25 at the periphery of the disk 3 are inclined so that a centre 38 of gravity of each plate blade 23 is below the line of its contact with a wall 39 of the slot 25.

The most reliable in operation is a grinder, according to the invention, in which the plate 28, as shown in Fig. 17, is made in the form of a disk screwed-in into a thread 40 in a cylindrical shell 41 of the housing 1 of the grinder. The plate 28 is fixed against slippage by means of an insert 42 put into a radial opening in the wall of the shell 41. The insert 42 is secured by a bolt 43.

As illustrated in Fig. 18, the insert 42 has at its one end 44 a thread the pitch and profile of which coincide with the pitch and profile of the thread 40 in the shell 41.

It is quite evident that the disks 2 and 3 are not necessarily made flat as shown in the figures of the drawings explaining the above modifications. The disks 2 and 3 may be of conical shape, as shown in Fig.

19, though other more intricate shapes of their surfaces are also possible.

It is also evident that the drive 4 may be coupled either with the upper disk 2 only, or through a differential reducing gear with both of the disks 2 and 3.

The above-disclosed grinder for the bulk materials operates as follows: The bulk material to be ground, is passed through the charging aperture 7 into the grinder. The particles of the material being ground are forced, by the impeller II actuated by the rotation drive 4, into the inner channels 13 of the closed zigzag contour formed by the ribs 5 and projections 12. The particles of the bulk material in the channels 13 pass down by gravity and under the action of the cutting disk 3 are moved by virtue of the centrifugal force along the edges of the cutting ribs 5 to the periphery, and at the points of intersection of the ribs 6 and 5 are subjected to the deformation of the slide cutting. Once having been separated from the basic particles of the material ground, the smaller particles with the size equal to the height of the cutting ribs 6 are forced thereby into the channels 14 and are thrown by the centrifugal force to the periphery of the disk into the discharge grooves 8 without being essentially subjected to any other destructive action such as crushing abrasion, etc.

In cases where the size of particles of the bulk material exceeds the height of the ribs 6 of the lower disk 3, said particles are gradually ground to the required size while passing through the zone of grinding of the corresponding number of the cutting ribs 6 in the channel 13.

The multistage grinder for the bulk materials, which is one of the modifications of the present invention operates in a similar manner, however, after the first step of the contour 17, the cut particles are not immediately forced to the periphery of the disk but are passed to the successive steps formed by the contours 16 and 15.

The modification of the grinder shown in Fig. 10, according to the invention, is used in both one-stage grinding and mutistage one. Such a constructional arrangement permits the height of the cutting ribs 6 of the lower disk 3 to be adjusted to the required one, which allows the size of the particles of the final product to be controlled.

Adjusting of the grinder is effected by loosening the nuts 31, 35, 30 and then turning the rods 27 and 26 respectively, so as to cause the plate blades 22 and 23 to lower into the slots 24 and 25, or extend therefrom, the upper disk 2 being displaced up or down over the same distance. If the disk rotates together with the plate 28 the bolt 43 is loosened. Varying the height of the protruding portion of the plate blades 23 enables the size of the final product to be controlled.

The replacement of the lower cutting blades 23 is done by merely lowering them into the slots 25, wherein they are secured by the centrifugal force produced by rotation of the disk. In comparison with the prior art the grinder, according to the invention, has the following advantages owing to its constructional arrangement. Quantity of the dust-like fractions formed in the process of operation of the above grinder is minimized, which permits the loss of the material to be reduced and the dust content in the production premises to be lowered, which in turn makes the additional air-filtering and dust-collecting equipment unnecessary. Another important advantage lies in that its energy consumption is lower than in the known machines of the same type, while its efficiency is higher.

While particular embodiments of the invention have been shown and described, various modifications may be made within the scope of the appended claims.

WHAT WE CLAIM IS: - 1. A grinder for the bulk materials, comprising a housing with an upper disk mounted therein and having a charging aperture in its central portion, cutting ribs disposed on the lower face of said disk and oriented from the centre towards the periphery, projections disposed on the lower face of said upper disk and running from the peripheral ends of the cutting ribs to the opposite ends of the adjacent cutting ribs so as to form, together with said cutting ribs, a closed zigzag contour, a lower disk mounted coaxially with the upper one and having cutting ribs disposed on its upper face, a rotation drive coupled with at least one of said disks.

2. A grinder according to claim 1, in which the cutting ribs and projections form, several closed concentric zigzag contours on the upper disk, and the surface of the lower disk has a stepped shape with the same number of the concentric circular steps the height of which gradually decreases from the centre towards the periphery of the disk.

3. A grinder according to claim 2, in which the width of each step is equal to the maximum distance between the adjacent zigzag contours disposed thereover and formed by the cutting ribs and projections of the upper disk.

4. A grinder according to claim 1, in which the cutting ribs of the upper and lower disks are made in the form of plate blades mounted in slots of said disks so that the height of the cutting ribs of the upper disk exceeds the height of the projections thereof 5. A grinder according to claims 4, in which the plate blades mounted in the slots of the upper and lower disks can be lowered and raised, permitting adjustment of the height of the cutting ribs.

6. A grinder according to claim 5, in which the plates with the plate blades are fixed to the upper and lower disks by means of rods with a variable length.

7. A grinder according to claim 6, in which the plate blades of the upper disk are fastened to the plate by means of rods having lugs at their ends, said lugs being set in the openings of said plate blades and fixed by means of pins resting upon the lower face of the upper disk and upper edge of the plate blades of said upper disk, while the plate blades of the lower disk are mounted in the open slots and rest with their lower edges upon the surface of the plate under the lower disk.

8. A grinder according to claim 7, in which the plate blades of the lower disk are of a trapezoidal shape and the walls of the open slots on the periphery of the lower disk are inclined so that the centre of gravity of each plate blade is below the line of their contact with the wall of said slots.

9. A grinder according to claim 6, in which the plate above the upper disk is

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. In cases where the size of particles of the bulk material exceeds the height of the ribs 6 of the lower disk 3, said particles are gradually ground to the required size while passing through the zone of grinding of the corresponding number of the cutting ribs 6 in the channel 13. The multistage grinder for the bulk materials, which is one of the modifications of the present invention operates in a similar manner, however, after the first step of the contour 17, the cut particles are not immediately forced to the periphery of the disk but are passed to the successive steps formed by the contours 16 and 15. The modification of the grinder shown in Fig. 10, according to the invention, is used in both one-stage grinding and mutistage one. Such a constructional arrangement permits the height of the cutting ribs 6 of the lower disk 3 to be adjusted to the required one, which allows the size of the particles of the final product to be controlled. Adjusting of the grinder is effected by loosening the nuts 31, 35, 30 and then turning the rods 27 and 26 respectively, so as to cause the plate blades 22 and 23 to lower into the slots 24 and 25, or extend therefrom, the upper disk 2 being displaced up or down over the same distance. If the disk rotates together with the plate 28 the bolt 43 is loosened. Varying the height of the protruding portion of the plate blades 23 enables the size of the final product to be controlled. The replacement of the lower cutting blades 23 is done by merely lowering them into the slots 25, wherein they are secured by the centrifugal force produced by rotation of the disk. In comparison with the prior art the grinder, according to the invention, has the following advantages owing to its constructional arrangement. Quantity of the dust-like fractions formed in the process of operation of the above grinder is minimized, which permits the loss of the material to be reduced and the dust content in the production premises to be lowered, which in turn makes the additional air-filtering and dust-collecting equipment unnecessary. Another important advantage lies in that its energy consumption is lower than in the known machines of the same type, while its efficiency is higher. While particular embodiments of the invention have been shown and described, various modifications may be made within the scope of the appended claims. WHAT WE CLAIM IS: -

1. A grinder for the bulk materials, comprising a housing with an upper disk mounted therein and having a charging aperture in its central portion, cutting ribs disposed on the lower face of said disk and oriented from the centre towards the periphery, projections disposed on the lower face of said upper disk and running from the peripheral ends of the cutting ribs to the opposite ends of the adjacent cutting ribs so as to form, together with said cutting ribs, a closed zigzag contour, a lower disk mounted coaxially with the upper one and having cutting ribs disposed on its upper face, a rotation drive coupled with at least one of said disks.

4. A grinder according to claim 1, in which the cutting ribs of the upper and lower disks are made in the form of plate blades mounted in slots of said disks so that the height of the cutting ribs of the upper disk exceeds the height of the projections thereof

5. A grinder according to claims 4, in which the plate blades mounted in the slots of the upper and lower disks can be lowered and raised, permitting adjustment of the height of the cutting ribs.

9. A grinder according to claim 6, in which the plate above the upper disk is

made in the form of a disk screwed-in into the cylindrical shell of the body of the grinder and fixed against slippage by means of an insert put into the circular opening in the wall of said cylindrical shell, fixed by the screw and having at one its end a thread, the pitch and profile of which coincides with the parameters of the thread on said shell.

10. A grinder substantially as herein described with reference to the accompanying drawings.