EP0658379B1 - Roller mill - Google Patents

Abstract

The roller mill has a grinding roller (1, 2) which revolves in a grinding ring (3, 4), the diameter of the grinding roller corresponding to at the least the inside radius of the grinding ring. The grinding roller (1, 2) is kept in motion by a tangential force from a drive (7). To this end, the drive (7) drives a drive table (20) to which two parallel stop beams (21) are fastened. Projecting between these beams is a stop body (23) which transmits the force to the grinding roller. The grinding roller (1, 2) and the grinding ring (3, 4) are each suspended on three universal shafts (6 and 5 resp.) and can be deflected laterally. This arrangement ensures that the centre of gravity of the grinding roller always revolves in the grinding ring at a constant revolving frequency. In addition, the suspension of the grinding roller by universal joints guarantees that its rotary impulse does not change during the revolving so that the torques acting on the mill housing remain small. <IMAGE>

Description

The invention relates to a roll mill according to the Preamble of the first claim.

A mill of this type is in US 2,303,387 disclosed. However, it has the disadvantage that it has a relatively low grinding capacity because it does not can be operated at high roller speeds and there is no uniform distribution of the regrind is guaranteed.

Mills with a grinding roller in a cylindrical grinding ring surface, and where the Diameter of the grinding roller at least the radius of the grinding ring surface are e.g. from WO 87/06500 and FR-349 886 known. By using such a large one There are several advantages to the grinding roller. So reduced especially the rolling resistance to non-generic Solutions with several smaller, on one level arranged grinding rollers, e.g. in EP-A-0 102 645 are described considerably. In addition, the mechanical Construction easier, e.g. less stock needed thanks to the large mass of Grinding roller less sensitive to hard foreign objects, such as e.g. Metal. In the previously known devices In this way, the grinding roller was usually swiveled suspended and driven by a drive to rotate around it brought own axis. This led to a rolling motion the grinding roller on the cylindrical grinding ring surface.

However, these known mills could be found in Do not enforce practice as they have various disadvantages to have. In particular, it has been shown that the Orbital frequency of the center of gravity of the grinding roller in the grinding ring surface (and thus also the centrifugal or pressure force) at a given drive speed, strongly from the diameter depends on the grinding roller. This effect makes itself felt increasing wear of the grinding roller noticeable. However, since the pressure force of the grinding roller on the grinding ring surface in Operation should remain essentially constant Systems of this type very complex speed controls and Gearbox for the drive as well as permanent monitoring the rotational frequency of the grinding roller.

Therefore the task arises of a roller mill to provide the type mentioned at the outset shows high grinding performance.

This object is achieved by the first claim described roll mill solved.

According to this solution, the drive does not work directly a rotation of the grinding roller around its own axis, but drives it by means of a tangential force component to circulate in the grinding ring surface so that it rolls on it. This allows the center of gravity of the grinding roller center of gravity controlled directly by the drive frequency become and is no longer of the grinding roller diameter dependent. The centrifugal resp. Pressing force of the The grinding roller on the grinding ring surface is therefore also a lot less dependent on the grinding roller diameter and changes even if the grinding roller wears out.

The grinding ring surface and / or are preferred The grinding roller is mounted so that it can be deflected laterally. As a result, the grinding ring surface has a lateral surface during operation Pendulum movement, the common focus of Grinding roller and grinding ring surface practically not deflected becomes. In this way, the load on the frame of the Mill diminished.

Storage of the grinding roller in is advantageous such that the direction of the mill roll axis at the Orbital movement remains essentially constant. Thereby becomes a periodic change in the angular momentum of the grinding roller avoided. In the known plants, where the grinding roller usually performs a swiveling movement when rotating, their angular momentum is constantly changed. this leads to to significant torques, especially at large Speeds and large grinding roll mass can hardly be absorbed are.

Preferably, the grinding roller is from one Grinding roller table held, gimbal attached to the grinding ring is. The grinding roller table is driven by the drive driven in a circular motion around the mill axis. Thus, the grinding roller and grinding ring form one together stored unit, the focus of which is stationary in operation remains. This reduces the dynamic loads that the frame of the mill is exposed.

Figur 1 einen Schnitt durch eine erste Ausführung der Mühle;

Figur 2 eine vergrösserte Ansicht des mittleren Teils von Figur 1;

Figur 3 eine Aufsicht auf die Mahlrollenhalterung;

Figur 4 einen Schnitt durch die Mahlrollenhalterung der Figur 3;

Figur 5 eine schematische Ansicht einer Kopplung zwischen Antrieb und Mahlrolle;

Figur 6 eine alternative Ausführung der Kopplung zwischen Antrieb und Mahlrolle;

Figur 7 einen Schnitt durch eine zweite Ausführung der Mühle, und

Figur 8 einen Schnitt durch eine dritte Ausführung der Mühle.

Further advantages and applications of the roll mill according to the invention result from the following description of two exemplary embodiments with reference to the figures. Show:

1 shows a section through a first embodiment of the mill;

Figure 2 is an enlarged view of the central part of Figure 1;

Figure 3 is a plan view of the grinding roller holder;

FIG. 4 shows a section through the grinding roller holder of FIG. 3;

Figure 5 is a schematic view of a coupling between the drive and grinding roller;

Figure 6 shows an alternative embodiment of the coupling between the drive and grinding roller;

7 shows a section through a second embodiment of the mill, and

Figure 8 shows a section through a third embodiment of the mill.

Figure 1 shows a section through a first Implementation of the invention. This is a Grinder for grinding gravel and stone, for example for Cement production.

The most important parts of the mill are the grinding roller 1, 2, the grinding ring 3, 4, the suspension 5 rsp. 6, the drive 7 with the coupling 8 between the drive 7 and Grinding roller 1, 2.

The grinding roller 1, 2 consists of an outer one Jacket 1 made of hard steel, e.g. High manganese steel, and one Core 2 made of aluminum. He is with a pivot bearing 9 a grinding roller holder 10 connected. This pivot bearing is coaxial to the axis of the grinding roller. The grinding roller is 1.2 thus about its grinding roller axis relative to the holder 10 rotatable. The grinding roller holder is schematic on three Cardan shafts 6 shown on the lid 11 of the frame of the Mill hung up. Each propeller shaft consists of three rigid ones Parts that are connected by two universal joints. By using at least one cardan shaft a rotation of the grinding roller holder 10 relative to the The frame of the grinder is prevented without having to swing out to the side the grinding roller holder would be hindered.

The grinding roller holder 10 consists of the Support structure as shown in Figures 3 and 4 becomes. It has three arms 12 for receiving the cardan shafts on. Baffles 13 for guiding the Grist provided. The screws for fastening the Bearings 9 are inserted into six holes 14. The grinding roller holder serves on the one hand to hold the grinding roller and on the other hand as a distribution plate for the from above the regrind falling into the opening 15 (FIG. 1).

From Figure 1 is outside the grinding roller 1.2 the grinding ring 3, 4 can be seen. This consists of a inner layer 3 made of high carbon steel, the surface of which is the grinding ring surface 16 forms, and an outer ring 4, which can be softer material. The grinding ring is over three Cardan shafts 5, only shown schematically, offset by 120 ° connected to the lid 11 of the mill frame. The usage prevented by at least one propeller shaft too here that the grinding rings 3, 4 turn against the mill can without a lateral deflection of the ring would be hindered.

There is a cylindrical guide plate on the grinding ring 46 provided, which prevents regrind falls laterally over the grinding ring.

A rubber ring 17 is located outside the grinding ring arranged. This acts as damping in the event that the grinding ring is deflected too much. Such strong excursions can in a low speed range when starting and / or the mill will leak if the Orbital frequency of the natural oscillation frequency of the pendulum body corresponds.

The motor 7 here is a three-phase motor with 30 kW power. It is via a gear, not shown in detail or just a coupling 18 of a known type connected to the axis 19 which rotates the drive table 20.

As best seen in Figure 2, there are two parallel to each other on the drive table Stop bar 21 arranged. Between these A beam is formed that runs radially on the drive table Guide track 22. A stop body projects into this 23, which is connected axially to the grinding roller 1 via a rotary bearing 24, 2 is connected. Seen from above, the one used here Stop body 23 has a rectangular cross section and has lateral slide bearing 25 (e.g. made of Teflon or nylon).

The three-dimensional arrangement of the stop bars 21 and the stop body is schematically again illustrated in Figure 5. In this figure, the Presentation of insignificant details in this context waived. It shows a view of the drive table 20, on which the stop bars 21 run. Between the stop bar protrudes from above the stop body 23, which is dashed here and without its arranged above it Suspension is shown. Between the stop bars a deflection bearing 26 is also attached, which a radial stop for the stop body 23 forms and deflects it from the mill axis 27 in the rest position. This ensures that the mill starts up safely. As soon as the drive starts to move the stop body 23 in the guideway along arrow A outwards and move a little upwards until the Grinding roller touches the grinding ring surface.

The coupling between the drive and the grinding roller This version must be such that it a tangential force component in the direction of rotation of the drive table can transmit, but a deflection the grinding roller to the side and upwards is not hindered. Instead of the stop bar 21 and the stop body 23 can e.g. as a coupling between table 20 and grinding roller also a rope sp. Chain arrangement can be used. Other couplings, e.g. Oil coupling or magnetic Couplings are conceivable. It is important that the transfer a force component tangential to the mill axis 27 is possible.

Figure 5 also indicates the course of a compressed air line 28 on. This is part of an overpressure system, by means of which dust is kept away from the bearings. The compressed air is for this purpose as shown in Figure 2 a hose 29 to the gearbox. the clutch 18 out. From there it reaches openings 30 and one Annular channel 31 for connecting piece 32 on the drive table. From there it is in the room via the flexible hose 28 33 led below the grinding roller 1, 2, from where it the Camp 9 and 24 can reach. This way all sensitive parts of the mill are under pressure and dust intrusion can be prevented. The pressurized system of the mill is replaced by suitable Seals of a known type isolated.

Figure 6 shows an alternative embodiment of the Coupling between drive and grinding roller. Instead of the stop bars 21 and the stop body 23 are here Grinding roller (not shown) and the drive table 20 over an articulated rod 40 connected. On hers the upper end is the rod 40 via a hinge joint 41 attached to the pivot bearing 24 'with a horizontal tilt axis. This pivot bearing replaces the bearing 24 in FIG. 2 and permits rotation of the grinding roller relative to the rod 40. At its lower end, the rod 40 is over a second one Hinge joint 42 attached to a lower pivot bearing 43. This pivot bearing 43 is connected to the drive table 20 connected. The pivot bearing 43 allows the rod 40 to be radial Follow movements of the center of the grinding roller. The hinges 41 and 42 allow the rod 40 to be vertical Compensate movements of the grinding roller.

In operation, the regrind is through the opening 15 introduced, lands on the grinding roller holder 10 and is thrown off to the side. Lateral form Material cone 35 and the material falls into the gap 36 between grinding roller and grinding ring. The orbital speed The grinding roller is so large that the Gap 36 falling material safely in one circulation Grinding roller is gripped and ground, i.e. that the minimum Fall time through the gap is greater than the round trip time the grinding roller is. The ground material then falls through a cylindrical space 37 outside the engine and leaves this room through floor openings (not shown).

A second version of the mill results from Figure 7. This mill has the same basic structure as those according to Figure 1 with grinding roller 1, 2, grinding ring 3, 4, drive 7 and coupling 8 between drive 7 and grinding roller 1, 2. The purpose of the coupling 8 is, in turn, one the grinding ring surface tangential to the grinding ring axis exert vertical force on the grinding roller 1, 2, so that this is driven to circulate in the grinding ring.

In contrast to the embodiment according to FIG. 1 here, however, the grinding roller 1, 2 is not directly on the mill frame hung up. Rather, it rests rotatable about a bearing 50 via an eccentric member 55 on a round eccentric plate 51. The eccentric plate 51 is in turn on a table 52 on. The eccentric plate 51 is on the side by guides 53 held and can rotate about the eccentric axis 54.

The table 52 rests with an axle 56 in a rotary bearing 57, by means of which it is connected to a holder 58 connected is. This bracket 58 includes radial struts 59 and a cylindrical jacket 60. The cylindrical Jacket 60 is fixedly attached to grinding ring 3, 4.

The axis piece 56 of the table 52 is also connected to the drive 7 via a cardan shaft 70. Alternatively, the drive 7 can be mounted directly on the holder 58 be flanged.

A distribution table is located above the grinding roller 1, 2 62 provided, the radial plates 63 with a frustoconical bracket 64 is connected, as well as a Filler neck 65. Bracket 64 forms a wall, which prevents material from going over the outer edge of the Rings 3, 4 falls.

In operation, the motor 7 drives via the cardan shaft 70 on the drive table 52. This turns it around the central axis of the grinding ring 3, 4. The eccentric plate 51 thus runs eccentrically around the central axis. she will orientate itself in their tours 53 in such a way that the eccentric 55 as far from the central axis is carried away that the grinding roller 1, 2 with the grinding ring 3, 4 comes into contact. Due to the centrifugal effect the grinding roller 1, 2 pressed against the grinding ring 3, 4 and rolls on this one.

A third and currently preferred version the mill is shown schematically in FIG. Also this mill has the same basic structure as that according to 1 and 7 with grinding roller 1, 2, grinding ring 3, 4, drive 7 and coupling 8 between drive 7 and grinding roller 1, 2. The purpose of the coupling 8 is, in turn, one the grinding ring surface tangential force on the grinding roller 1, Exercise 2 so that it can circulate in the grinding ring is driven.

As in the embodiment according to FIG. 7, the Grinding roller 1, 2 attached to grinding ring 3, 4 here. For this the grinding roller has a central rotary bearing 50 which it is connected to the roller table 52 '. Roller table 52 'and grinding roller 1, 2 are coaxial with each other rotatable. The roller table 52 'rests on three or four cardan shafts 75, of which only two in Fig. 8 in schematic Are indicated. The cardan shafts 75 are on Support elements 76 which are fixed to the outside Part 4 of the grinding ring are connected. So make up Grinding roller 1, 2 and grinding ring again a dynamic one Gimbal joint unit 5.

The motor 7 is fixed to the mill frame connected. A motor table 76 rests on the motor axis 19. Is located between the motor table 76 and the roller table 52 ' a rope coupling 77 - 79. This includes one first anchoring pin attached eccentrically to the motor table 77, a second, attached to the roller table Anchoring pin 78 and one movable with both anchoring pins connected rope 79. The mutual situation the anchor pins and the length of the rope are like this dimensioned that the roller table 52 'by the rotational movement of the motor table 76 on a circular path around the mill axis is pulled along. The radius of this circular path is so large that the grinding roller 1, 2 with the grinding ring 3, 4 safely in Contact comes and can roll on this.

Instead of the rope coupling 77 - 79 you can also one of the couplings according to FIG. 5 or 6 can be used.

Furthermore, the motor 7 can also be outside the Axis of the mill can be arranged by motor 7 and coupling 77 - 79 can be moved in parallel. The radius r of the When new, the grinding roller is 35 cm, the inner radius R of the grinding ring 40 cm. The roller and ring are useful in operation so that in extreme cases r = 30 cm and R = 45 cm can.

Thanks to the drive that is directly on the orbital movement the center of gravity of the grinding roller acts in the grinding ring, the orbital frequency of the grinding roller center of gravity remains in Grinding ring constant since it is the rotation frequency of the drive table corresponds. The pressure force also changes the role on the ring only slightly depending on the wear of roll and ring. The speed of the drive is in the present example 750 revolutions per minute.

So in the present construction it is Rotation frequency F of the center of gravity of the grinding rollers in the grinding ring equal to the rotational frequency of the drive table resp. Drive. The rotational frequency W of the grinding roller around itself is however not the same as F resp. f, but depends strongly on the ratio r / R. If r / R goes against one, then F / W very large. However, this interferes with practical operation Not.

In contrast, in the known arrangements according to the prior art, as described, for example, in WO 87/06500, the rotational frequency F of the center of gravity of the grinding rollers in the grinding ring is given by the formula F = fxr / (R - r) given, where f is the speed of the motor and the roller. Here, with a large radius r of the roller (r approximately equal to R), the rotational frequency F of the roller center of gravity is strongly dependent on the wear of the roller and the ring and is much larger than the drive frequency f. In order to achieve uniform grinding conditions, these known mills must therefore be provided with a controllable drive and a large reduction, which brings considerable problems and costs with larger plants, such as those used in cement production. These problems do not occur in the mill according to the invention.

Claims (13)

1. Roller mill with a milling roller (1, 2), a substantially cylindrical milling ring surface (16) and a drive (7, 8), wherein the milling roller (1, 2) has a diameter, which is approximately as large as or lager than the radius of the milling ring surface (16), and wherein for milling the milling roller (1, 2) is rotating about a milling roller axis and is rolling on the milling ring surface (16), wherein the milling roller (1, 2) can be freely rotated about the milling roller axis and a force component tangential the milling ring surface (16) can be exerted onto the milling roller (1, 2) by means of the drive (7, 8), characterised in that the milling roller (1, 2) and a milling ring (3, 4) forming the cylindrical milling ring surface (16) are mounted in laterally displaceable manner and that a distributing table (62) for material to be milled is arranged on the milling ring (3, 4) above the milling roller (1, 2).
2. Roller mill of claim 1, characterised in that the milling roller is mounted in such a way that the direction of the milling roller axis always remains the same during milling.
3. Roller mill of one of the preceding claims characterised in that the milling roller (1, 2) is held by a milling roller table (52, 52'), wherein the milling roller table (52) is rotatably arranged on a milling roller table holder (58; 75, 76) and wherein the milling roller table holder (58) is fixed in position in respect to the milling ring surface (16).
4. Roller mill of claim 3, characterised in that the milling roller table (52') can be driven to a circular motion about the central axis of the milling ring (3, 4).
5. Roller mill of one of the claims 3 or 4, characterised in that the milling roller table (52) is connected to a drive (7, 19) by means of a cardan shaft (70).
6. Roller mill of one of the preceding claims characterised in that it comprises a resting frame (11) and that the milling ring (3, 4) cannot be rotated in respect to the frame (11).
7. Roller mill of one of the preceding claims characterised in that the milling roller (1, 2) is connected to a rotating drive shaft (19, 20) by means of a coupling means (8), wherein the milling roller (1, 2) can be rotated in respect to the coupling means (8).
8. Roller mill of claim 7, characterised in that the coupling means (8) comprises at least two stopping elements (21, 23), a first (21) of which is connected to the driving shaft (19, 20) and a second of which is connected to the milling roller (1, 2), wherein the tangential force component can by transmitted by means of the stopping elements (21, 23).
9. Roller mill of claim 7, characterised in that the coupling means comprises a coupling member (40), which is connected by a first joint assembly (24', 41) with the milling roller (1, 2) and by a second joint assembly (42, 43) with the driving shaft (19, 20).
10. Roller mill of claim 7, characterised in that the coupling means (8) comprises a roller table (52'), which is connected to the milling ring in non-rotational but laterally displaceable manner and which can be driven in a circular motion about the central axis of the milling ring (3, 4).
11. Roller mill of one of the preceding claims characterised in that in a resting position of the roller mill the milling roller (1, 2) is moved out of the centre of the milling ring surface.
12. Roller mill of one of the preceding claims characterised in that a wall (46, 64) is arranged on the milling ring (3, 4) in order to prevent that material to be milled falls over the outside of the milling ring.
13. Roller mill of one of the preceding claims characterised in that a damping element (17) for damping of strong movements of the milling ring (3, 4) is arranged outside the milling ring (3, 4).

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