EP0135568B1 - Fine grinding installation for laboratory experiments - Google Patents

Abstract

In installations for fine grinding particularly of material samples for laboratory experiments, with a fixed grinding member and a rotating grinding member, arranged so as to have a surface facing another one with a small gap and through which the product to be ground is supplied, the following problem is raised: the samples have to be introduced and discharged one by one so that the work is carried out in batch process. It is also difficult to adjust accurately the grinding degree. In order to solve this problem and to carry out a continuous grinding of hard and very hard materials, as well as an adjustable grinding in relation to the grain size, the grinding members according to the present invention have on one hand a structure of a fixed cylinder body (22) and on the other hand a structure of a cylinder core (26) rotating in parallel to the shaft; between them, an annular narrow passage, preferably about half millimeter large, remains free. The product to be ground is introduced on the front side of the cylinder core, and the ground product is discharged on the other front side of the cylinder core; corresponding devices (20, 36; 21, 37, 38) are provided to this effect. The common longitudinal medial axis of both grinding members may be tipped by appropriate mechanisms (11, 12, 15) so as to assume a substantially vertical position while passing by numberless inclined position. A conical element (30) in the top surface of the cylinder core (26) may be arranged on at least one front side of the latter.

Description

The invention relates to a device for the fine comminution of, in particular, material samples for laboratory purposes with a fixed and a revolving comminution organ, each with a surface at a distance from one another and the material to be ground temporarily arranged between them, the comminution organs on the one hand having a cylinder jacket which is fixed against rotation and on the other hand a roller body rotating in the same axis is provided, between which the regrind is conveyed in an annular gap from a task on one end face of the roller body, in particular via depressions arranged on the roller body, to a discharge on the other end face of the roller body.

A shredding device with the above generic features is known from FR-A 2 183 676. This design, which is essentially designed as a mixing and refining device, is also used for comminution of regrind, which is conveyed on the way from the regrind feed to the regrind discharge via an axial annular gap arranged between it, between a fixed casing and a rotating roller body and thereby into the annular space both from the Jacket is crushed inwards as well as blow bars protruding outwards from the roller body.

The disadvantage of such a device is that only a comparatively narrow range of regrind can be comminuted, the fineness of the end grain of the regrind being adjustable only by inserting more or less protruding blow bars into the comminution members; for this reason, especially during the grinding process, it is no longer possible to adjust the grinding action. This results in a further disadvantage that the known comminution device cannot readily be used for a large hardness range of material to be comminuted, since softer materials require a different comminution characteristic than harder ones.

The invention is therefore based on the object of improving a comminution device of the type mentioned at the outset in such a way that it can be used for comparatively soft, hard and also the hardest materials without modifications. The device should be able to work continuously and the size reduction with respect to the grain size in the discharge should be able to be regulated to a very large extent. The task also includes the requirement for a compact design to adapt to the space available in laboratories and for a dustproof design.

The solution to this problem according to the invention results, including advantageous refinements and developments, from the content of the claims, which are presented after this description.

With the invention, the laboratory operation is advantageously provided with a mill in which not only coal and coke as examples of comparatively soft materials, but also, for example, limestone, cement and very hard ores can be pulverized, the grain size of the task preferably up to can be up to 8 millimeters, while a grain size of up to about 10 microns can be achieved in the discharge. The difference in grain size does not always have to encompass the aforementioned range, but rather smaller ranges can also be set. The device records a hardness range of 3 - 10 degrees on the Mohs hardness scale.

An essential feature of the device according to the invention is that, depending on the degree of hardness of the feed material, an adjustable, grinding grinding action is ensured, which is supported by a striking grinding action to the extent that the roller body rotating in the fixed cylinder jacket tumbles or prances within the jacket during operation Movements are carried out, but not the roller itself is caused to make these movements, but a corresponding effect is brought about by the fact that the cylinder jacket can move by a small amount relative to the roller, preferably under the influence of flexible components, for example mechanical compression springs or hydraulic ones Printing units. The movement processes in the device which are brought about in this way contribute to promoting the flow of material from the task to the discharge and also prevent it from sticking in the shredding area. Both dry and wet regrind can be processed.

Brief description of the drawings

In the drawing, an embodiment of the invention is shown, which is described below.

• Fig. 1 eine Seitenansicht der Zerkleinerungsvorrichtung, teilweise axial längsgeschnitten,
• Fig. 2 einen Querschnitt nach Linie 11-11 in Fig. 1,
• Fig. 3 einen Querschnitt nach Linie 111-111 in Fig. 1,
• Fig. 4 eine Seitenansicht der Zerkleinerungsvorrichtung in hochgeschwenkter Stellung,
• Fig. 5 eine Seitenansicht einer anderen Ausführungsform der Zerkleinerungsvorrichtung mit säulenförmigem Untergestell, in zwei Betriebssteilungen,
• Fig. 6 eine Seitenansicht der Zerkleinerungsvorrichtung gemäss Fig. 5, teilweise axiai längsgeschnitten.

Show it:

• 1 is a side view of the crushing device, partially axially longitudinally cut,
• 2 shows a cross section along line 11-11 in Fig. 1,
• 3 shows a cross section along line 111-111 in FIG. 1,
• 4 shows a side view of the shredding device in the swiveled-up position,
• 5 is a side view of another embodiment of the shredding device with a columnar base, in two operating divisions,
• Fig. 6 is a side view of the shredding device according to FIG. 5, partially axially cut longitudinally.

In the exemplary embodiment of the comminuting device shown in FIGS. 1-4, a support plate 12 is mounted on a table-like base frame 10 so that it can pivot about an axis 11 wearing. The support plate 12 with grinding device 13 and motor 14 can be tilted about the axis 1 by means of handles 15 (cf. FIG. 4), namely the tilting or swiveling angle is 90 degrees, all intermediate positions being infinitely adjustable. A scale 16 is used to precisely determine the angle of inclination a knurled wheel 17 which acts on a suitable clamping device (not shown) which fixes the support plate 12 in the desired position.

The grinding device 13 consists of a tubular housing 18 made of cast steel or light metal, which is provided on the outside with numerous longitudinal cooling fins 19. The end faces of the housing 18 are closed by closure pieces 20, 21, which are designed differently and allow the task or the discharge of the goods in a manner to be described. Arranged in the interior of the housing is a fixed comminution member in the form of a cylindrical shell 22 which cannot move relative to the housing 18 and is made, for example, of steel or ceramic. The inner surface of the jacket 22 is absolutely cylindrical and smooth, preferably very finely ground or polished.

The housing 18 rests on bearing blocks 23, each of which is essentially formed by a helical compression spring 24, as a result of which the housing is both movable within limits and has a relatively upward tendency to exert force.

In the interior of the housing 18 with the cylinder jacket 22, a roller body 26 is arranged on an axially extending shaft 25, the outside diameter of which is so much smaller than the inside diameter of the cylinder jacket 22 that a cylindrical annular gap of approximately 0.2-0.4 between these two parts mm gap width arises. The outer surface of the roller body 26 is also very finely smoothed or polished and, with the exception of two flats or chamfers 27, absolutely cylindrical. The chamfers 27 result from Fig. 2; they are arranged adjacent and abut one another in a roof-shaped manner, resulting in a narrow ridge surface 28 which extends in continuation of the outer surface of the roller body. The chamfers 27 create two adjacent longitudinal spaces 29 in the interior of the device, the cross section of which is essentially in the form of a segment of a circle. The roller body 26 consists in particular of steel and, if possible, has the same hardness as the cylinder jacket 22. The hardness of both comminution members 22, 26 should be greater than the hardness of the material to be comminuted.

In the embodiment shown in the drawing, there is a cone body 20 as a pre-comminution member on the right end face of the roller body 26. The outer surface of the cone body 30 merges into the outer surface of the roller body 26, but is provided with triangular grooves 31 which run in the axial direction and run from a largest cross section at the narrow end of the cone body 30 to a smallest cross section at the wide end of this body. In the area of the cone body 30, the inner surface of the cylinder jacket 22 can also be provided with correspondingly parallel grooves 32, as can be seen in FIG. 3.

The combined roller-cone body 26, 30 is supported with its shaft 25 in smooth-running roller bearings 33, and the shaft 25 is in a fixed drive connection to the motor shaft of the electric motor 14 via a coupling 34. In this way, the motor conveys a revolving speed of 3000 rpm to the rotating comminution member 26 30. A cooling fan 35, which is also arranged on the support plate 12, can be driven by the same shaft 25 by the motor 14. The cooling fan generates an air flow over the housing 18 and its cooling fins 19.

As mentioned, the closure pieces 20, 21 are designed accordingly for the task and the discharge of the regrind, namely the closure piece 20 arranged on the feed side is provided with a funnel 36 which extends into the upper half of the casing 22 in the region of the narrow end of the cone body 30 opens. The closure piece 21 on the discharge side of the housing 18 has a chamfer 37 on the inside, which opens into a lower opening 38 through which the comminuted material lusts the mill. During operation there is a constant flow of material from hopper 36 to opening 38, i.e. there is a continuous comminution process as long as new material is fed into the hopper 36.

In operation, the raw material first reaches the area of the cone body 30 from the mouth of the funnel 36, where a pre-comminution takes place. The grain size obtained must correspond to the annular gap between the jacket 22 and the roller body 26. A progressive comminution then takes place in this annular gap during the further passage in the direction of the closure piece 21, the material itself - although not exclusively - acting as a grinding tool. The longitudinal spaces 29 formed by the chamfers 27 serve essentially for transport in the radial direction and for preventing blockages due to clumping. The longitudinal edges of rooms 29 take part in the shredding to a certain extent like tools.

The conveying of the millbase in the axial direction of the machine takes place only to a small extent under the influence of the constantly supplied raw material via the funnel 36, rather the conveyance is primarily caused by the gradient, which can be communicated to the housing 18 by tilting about the axis 11. The steeper the inclined position of the mill, the faster the material passes through the various comminution zones, so that the length of time of the material between the comminution elements is a function of the angle of inclination. This means that the degree of comminution is usually dependent on the set gradient, although the hardness of the material also plays a role. Another aspect arises from the moisture content of the raw material; The more wet the raw material is fed in, the more finely the discharge is generally crushed. The scraping effect of the longitudinal edges of the chamfers 27 is significant, particularly in the case of wet goods, i.e. the edges act as wipers.

In the comminution, the mounting of the housing 18 on the helical compression springs 24 plays an important role, because the jacket 22 is thereby pressed upwards and with the lower half of its inner surface against the lower half of the outer surface of the roller body 26. Since the housing 18 carries out prancing movements during operation, this occurs between the shredding organs signs of movement that influence the comminution. So that the vibrations of the housing 18 are kept within limits, especially when resonance vibrations cannot be ruled out, holding plates 39 are provided which surround the housing 18 with little play.

When the respective shredding program has ended and a new program with different raw material and possibly different shredding conditions is to be switched on, the machine must be cleaned. Since the discharge of shredded material is used for laboratory purposes, it is important that no residues from previous programs are contained in the current regrind, i.e. it must be possible to clean the machine very carefully. It is important that the cleaning can be carried out easily so that this does not result in a greater expenditure of time. This is ensured in the device according to FIG. 1 that in the drive shaft unit 25, 33, 34 a coupling member 40 is switched on, which essentially consists of a coupling sleeve seated on the shaft 25, which is pushed back so far against the spring pressure on the shaft 25 can be that it releases the subsequent shaft end 41. It is now possible to grasp the housing 18, lift it and pull it out obliquely upwards from the bearing 33 on the feed side. The closure pieces 20, 21, which are fastened in a conventional manner in the tube ends of the housing 18, can be easily removed, as a result of which there is nothing standing in the way of removing the roller body 26. The crushing elements 22, 26, 30 can thus be easily and completely cleaned. The subsequent assembly of the machine is accordingly quick and easy. Even during a grinding process, it is not particularly difficult to remove the roller body 26 in the manner described, for example if a disturbance due to a foreign body should have occurred. All of these circumstances make the possibility of using the described crushing device with the appropriate dimensioning also in the context of an ongoing production operation not seem excluded.

5 and 6 a further embodiment is shown, the difference from the embodiment according to FIGS. 1-4 in particular in the design of the chassis or base and in the storage of the crushing elements and the electric motor.

This is a table-top device with a column 43 which rises on a footplate (not shown) and which is designed in the middle as a joint or pivot bearing 44. This has a scale 16 and a knurled wheel 17 which acts on a suitable clamping device (not shown) which fixes the comminution device in the desired position, for example in the inclined position shown in FIG. 5 by dash-dotted lines.

While the shaft 25 carrying the roller body 26 is supported on both sides of the ends of the roller body in the embodiment according to FIGS. 1-4, the bearing in the embodiment according to FIGS. the roller body 26 is connected at only one end to the associated drive shaft, here the shaft 45, so that it protrudes into the cylinder jacket 22. The cylinder jacket 22 is also supported in a self-supporting manner, and the same arrangement principle is also implemented on the opposite side of the shaft 45, where the electric motor 14 with the rotor shaft 46 is located in a correspondingly self-supporting arrangement. However, the rotor shaft is supported in the conventional manner at its two ends in the motor stand (not shown). This results in a three-part arrangement of the components, namely in the middle the shaft 45 and axially on both sides of it the roller body 26 with the jacket 22 and the electric motor 14. The pivot axis for inclining the comminution members 22, 26 is in this configuration in the middle region namely below the shaft 45 in the pivot bearing 44. This also results in a particularly good handiness of the device.

6 shows the details of the exemplary embodiment shown externally in FIG. 5. The upstanding column 43 is box-shaped hollow above the pivot bearing 44 and serves as a carrier for the shaft 45 and thus also for the self-supporting components arranged on both sides, namely the crushing elements 22, 26 and the motor 14 with rotor shaft 46 Wall of the upper part of the column 43 fastened in corresponding openings bearing flanges 47, 48, in which there are ball or roller bearings 49, 50, between which the shaft 45 extends. This shaft 45 is a hollow shaft in the form of a sleeve open on both sides with different inner diameters (cf. FIG. 6). The inside of the shaft 45 serves on the motor side for the positive reception of the rotor shaft 46 of the electric motor 14, while the shaft 45 is provided on the other side for receiving an axle stub 51 which is integral with the roller body 26. In this way, the shaft 45 forms a coupling connection between the motor 14 and the roller body 26.

On its outer circumference, the shaft 45 carries an impeller 52 of an axial fan, which rotates with the shaft 45. As a result, cooling wind is sucked in from below through the upper part of the column 43 according to the arrows 53 and, after being deflected and bundled at right angles, passed through a nozzle-shaped guide plate 54 via the comminution members 22, 26. While the suction openings for the cooling wind in the column 43 are not shown, the outlet openings for the used cooling medium from FIG. 6 result from the reference number 55.

While the electric motor 14, which is designed as a flange motor for this purpose, is screwed onto the flange 48 outside the column 43, a sleeve-like housing 56 connects to the other flange 47, in which the comminution members 22, 26 with the filling funnel 36 and discharge tube 57 are accommodated . A bottle 58 is connected to the discharge pipe 57 as a collector for the comminuted material. In the interior of the housing 56, the outer casing 59 of the cylindrical comminution member 22 is behind via the resilient bearing blocks 23 supported extensively so that the jacket 22 surrounding the roller body 26 can move in relation to the roller body, should this be necessary, for example, due to material accumulations or foreign bodies. The housing 56 is fastened to the column 43 by means of three clamping screws 60, which can be loosened in a conventional manner for removing the housing 56 and each pivoted outwards. When the housing 56 is attached to the column 43, the open edge of the housing is pushed over the correspondingly graduated outer edge 61 of the flange 47, the annular edge of the jacket 22 resting against a flexible seal 62, and the clamping screws 60 are then tightened. With this construction, the casing 22 can be removed very easily from the roller body 26, for example for cleaning purposes or for exchange for another casing 22 which is more suitable for the next shredding process.

In this exemplary embodiment, the roller body 26 is also combined with a cone body 30 as a pre-comminution member. The outer surface of the cone body 30 merges into the outer surface of the roller body 26, as is also the case in the exemplary embodiment according to FIGS. 1-4. On the conical body 30, however, the stub shaft 51 connects here, with which the inner comminution member 26 is fastened to the shaft 45 in a slightly exchangeable manner. A grub screw 63 serves to secure the attachment.

In operation, the processes take place as has already been described with reference to the exemplary embodiment according to FIGS. 1-4. In the exemplary embodiment according to FIGS. 5 and 6, the prancing movements of the jacket 22 or 59 mentioned there relative to the roller body 26 can be influenced by a regulating screw 64, which acts on the outer bearing block 23.

Claims (19)

1. Apparatus for fine grinding of in particular material samples for laboratory experiments, with a fixed grinding member and a rotating grinding member, which are disposed in such a was that each has a surface which faces the other and is spaced therefrom, with the material which is to be ground being received and passed between these surfaces, the grinding members being constructed on the one hand as a cylindrical body which is fixed against rotation, and on the other hand as a roller body which rotates coaxially therein; a small annular gap remains between the two bodies; the material which is to be ground is conveyed between this annular gap from an introducing means on one end face of the roller body to a discharge on the other end face of the roller body along grooves being disposed in particular at the roller body, characterized in that the housing (18, 59) which surrounds the cylindrical body (22) is mounted on elastic bearing blocks (23, 24), the degree of elasticity of which is adapted to be adjustable by means of a hand grip (64), in such a way that the lower half of the inner surface of the cylindrical body (22) is pushed upwardly against the lower half of the outer surface of the roller body (26).

2. Apparatus according to claim 1, characterized in that the elastic bearing blocks (23) are essentially formed by respective compression springs (24).

3. Apparatus according to claim 1, characterized in that the common central longitudinal axis of the two grinding members (22, 26) is basically horizontal and can be pivoted by suitable means (11, 12, 15, 44) through numerous inclined positions up to an essentially vertical position.

4. Apparatus according to claim 3, characterized in that the housing (18), together with its units and the drive (14), is mounted on a chassis (12) which can be pivoted by means of a hinged connection (11) about approximately 90 dregrees between a horizontal and a vertical position, and can be fixed in any position, even in intermediate positions.

5. Apparatus according to claim 4, characterized in that the hinged connection (11) for the pivotable mounting is equipped with a scale (16) and with means (17) for fixation pursuant to values shown on the scale for the time that the material which is to be ground remains in the apparatus.

6. Apparatus according to claim 4, characterized in that the chassis is in the form of a column (43) having a base plate, and in that on or near the upper end of the column, (43), the housing (56, 59) together with its units (22, 26), hangs over to one side, and the electric motor (14) hangs over on the other side, with both the electric motor and the housing being pivotable in common and being mounted in such a way that they can be fixed in any position.

7. Apparatus according to claim 6, characterized in that the housing for the grinding members (22, 26), the cover (43) of the shaft (45), and the outer casing of the electric motor (14) are designed together as a uniform and essentially cylindrical body.

8. Apparatus according to claim 6 or 7, characterized in that the fixed cylindrical body (22, 59) is in a form of a housing which is open on one side and has an end wall, and in which the roller body (26, 30) is rotatably mounted in an overhung arrangement on a shaft (45) which on its opposite end is coupled with the rotor shaft (46) of an electric motor (14), with the roller body (26, 30), the shaft (45) and the rotor shaft (46) being disposed in such a way that they extend coaxially.

9. Apparatus according to claim 8, characterized in that the shaft (45) which holds and drives the roller body (26, 30) is in the form of a hollow shaft, and at one end receives in its hollow interior an easily replaceable shaft neck (51) which is preferably formed integrally onto the roller body (26, 30) and firmly holds the latter in place on the shaft (45) in a self-supporting manner.

10. Apparatus according to claim 9, characterized in that the shaft (45) is accomodated in the upper part of the column (43), where it is supported by flanged bearings (47, 48) on which there is mounted on the one hand on the outside thereof the electric motor (14), and on the other hand there is mounted the outer housing (56) which receives the grinding apparatus (13) via the elastic bearing blocks (23, 24).

11. Apparatus according to claim 10, characterized in that the outer housing including the body part (22) of the grinding apparatus (13), is mounted on the column (43) in an easily removable manner by means of attachment screws (60).

12. Apparatus according to claim 1, characterized in that the cylindrical body (18, 22) is provided on the outside with means for increasing the surface area, especially with longitudinal ribs (19), for dissipating heat.

13. Apparatus according to claim 12, characterized in that a cooling wind generator (35) is disposed in the vicinity of the housing (18, 19, 59) which is provided with the increased surface area.

14. Apparatus according to claim 13, characterized in that the drive shaft (25, 45) of the roller body (26) is provided with fan blades (52) which have a slope which conveys the cooling air over the surfaces of the housing (18, 59).

15. Apparatus according to claim 6 and 13, characterized in that the cooling wind generator (52) is mounted on the shaft (45) which drives the roller body (26, 30), and in that the interior of the column (43) is constructed as an intake connection for the cooling wind.

16. Apparatus according to claim 15, characterized in that the direction of conveyance of the cooling wind generator (52), and in the vicinity thereof, there is disposed a funnel (54) which tapers in this direction and is in the form of a nozzle for concentrating the cooling wind which passes over the body (22, 59) of the grinding apparatus (13).

17. Apparatus according to claim 7 and 13, characterized in that the coaxial and successive arrangement of the grinding apparatus (13), the shaft (45), and the electric motor (14) is in the form of a linear cooling wind channel with cooling wind intake openings being provided on the side of the electric motor (14), and cooling wind exhaust openings (55) being provided on the side of the discharge conduit (57) for the material which is ground, while the cooling wind generator (52) is located on the shaft (45) in the middle region of the arrangement.

18. Apparatus according to claim 1, characterized in that the roller body (26), in a manner known per se, is provided with two roof-shaped abutting flattened or champfered portions (27) which extend over the entire length of the roller, and in that the ridge (28) formed by the flattened portions (27) of the roller body (26) is formed by a narrow strip of the roller body.

19. Apparatus according to at least one of the preceding claims, characterized in that a collecting container (58) for the ground material is connected to the discharge opening (38) or to the discharge conduit (57), so that this container follows the pivoting movements of the grinding apparatus (13, 22, 26, 30).

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