GB2265844A

GB2265844A - Grinding roll apparatus.

Info

Publication number: GB2265844A
Application number: GB9304514A
Authority: GB
Inventors: Hermann Stein; Rainer Haussig; Siegfried Voigt
Original assignee: WIRTH MUEHLENBAU DRESDEN GmbH
Current assignee: WIRTH MUEHLENBAU DRESDEN GmbH
Priority date: 1992-03-17
Filing date: 1993-03-05
Publication date: 1993-10-13
Also published as: IT1261413B; GB9304514D0; CZ20893A3; DE4208488A1; ITRM930158A0; ITRM930158A1

Abstract

The apparatus comprises a base, a pair of grinding rolls 5.1, 5.2 mounted on respective pairs of roll carriers 8.1, 8.2 and 10.1. 10.2, adjusting means 14 for adjusting the grinding gap 6; the assembly of rolls, carriers and adjusting means represents an exchangeable assembly; the carriers 8.1, 8.2 are pivotably mounted at the base and the carriers 10.1, 10.2 are pivotably mounted at carriers 8.1, 8.2 (Figures 1, 2) or at the base (Figure 4). As shown, a feed slide with feed roll pair 4 serves for regulation of stock to be milled. Roll carriers 8.1, 8.2 are mounted at members 1.1,1.2 by way of inlet bushings 15.1, 15.2 or bearing blocks 18.1, 16.2 connected by vibration clamps 17.1, 17.2 with members 1.1, 1.2. Adjusting means comprising spindle 14 connected to carrier pairs at pivot points 18, 19 at least one of which has eccentric form. <IMAGE>

Description

GRINDING ROLL APPARATUS The present invention relates to milling

installations and has particular reference to grinding roll apparatus.

Grinding rolls have to absorb appreciable static and dynamic loadings during grinding operations. These dynamic loadings,caused by high grinding pressures, arise during grinding work in which extremely high dynamic forces are present, particularly in the case of smooth rolls and fine roll precisions. The specific throughputs, which continue to climb, further increase this effect. These forces are usually transmitted to side walls of the apparatus housing by way of bearings fixed in the side walls. In order to avoid undesired vibration of the side walls and thus generation of noise, these side walls must be very rigid and -stiff. This requires a heavy and expensive housing construction.

Apparatus in which these undesired effects are reduced is known from DE-OS 27 30 166. In that case,. a'rigid frame carrier, on which bearings of the grinding rolls are ounted, is arranged below the rolls. The carrier is mounted by way of an intermediate damping member in a base stand of the roll frame. The grinding rolls and a few functionally associated elements are combined into a constructional unit, the roll assembly. This assembly is easily removable from the roll frame and can be exchanged in the case of wear or other circumstances.

2 Due to the roll assembly, the dynamic forces are absorbed by the frame carrier and not introduced into the side walls to the same extent as before. However, it is disadvantageous in this solution that the side walls must nevertheless be constructed to be very rigid, since these absorb not only the remaining dynamic forces but also the appreciable static forces of the roll assembly. Moreover, the transmission of vibration is not completely avoidable in spite of the damping members. Since the large area side walls arranged at the base stand absorb vibrations, noise generation is not avoidable even though it is less.

There is therefore a need for an arrangement for reception of a grinding roll pair, which keeps vibrations induced by the dynamic loading of the rolls during grinding operations away from a base stand.

According to the present invention there is provided grinding roll apparatus comprising a stand supported on a foundation, a pair of grinding rolls and means for adjusting the spacing of the rolls from each other, wherein the mounting of the rolls and the-rolls.t-hemselves form an independent unit removable from the apparatus and wherein first roll carriers, which are associated with the foundation, are associated with the spigots of a first one of the rolls and second roll carriers which bear on the first roll carriers and are arranged to be pivotable on pivots, are associated with the spigots of the second one of the rolls.

Preferably, bearing blocks, which define bearing points and in which the first roll carriers are mounted, are arranged at the foundation frame. In one preferred embodiment the bearing points coincide with the pivots. The mounting of the roll carriers in the bearing blocks can be effected by way of silent bushings and the bearing blocks can be connected by way of vibration dampers with the foundation frame.

For preference, pivots, of which at least one is constructed as an eccentric and in conjunction with 'a lever serves for the adjustment of the grinding gap, are arranged above the two roll carriers. An adjusting device can be pivotably connected with one set of roll carriers and the lever.

Apparatus embodying the invention may have the advantage that the noise level on the grinding floor is appreciably reduced and the construction of the roll stand housing, in particular that of the side walls, may be able to be very light, since this now has only the function of a cladding and serves for the reception of feeding equipment. Consequently, material is saved and the need to load the ceiling at the place of installation may be reduced. Due to the 2() structuring of the roll stand the operator may benefit from a higher rigidity, reduced noise output, ease of operation during the roll change, and the possibility of re-equipping, if so desired, the roll stand at low cost with rolls of a different diameter.

4 Embodiments of the present invention will now be more particularly described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic elevation of one half of a double roll stand embodying the invention; Fig. 2 is an end view, from the operating side, of the roll stand of Fig. 1; Fig. 3 is a schematic elevation of one half of a double roll stand similar to that of Fig. 1, but with rolls of different diameter; and Fig. 4 is a schematic elevation of one half of a further double roll stand embodying the invention.

Referring now to the drawings, there is shown in Figs. 1 and 2 a roll stand comprising a base stand formed by foundation frame members 1.1 and 1.2 and a central rigid middle wall 2. An inlet 3 is provided in the upper part. A feed slide (not shown) with a feed roll pair 4 serves for regulation of the inflow of stock to be milled. The regulation of the inflow of the stock and the components necessary for this do not concern the invention and therefore are not illustrated or further described.

A grinding roll pair, consisting of grinding rolls 5.1 and 5.2, is disposed below the feed roll pair 4. A grinding gao 6 is present between the grinding rolls.

The mounting of the grinding roll pair is evident from Fig. 1 in conjunction with Fig. 2. The foundation frame members 1.1 and 1.2 are set onto a foundation 7 which is, as a rule, the milling floor of a mill. Respective roll carriers 8.1 and 8.2 are arranged at the two ends of the grinding roll 5.1 and are mounted at pivots 13.1 and 13.2, respectively. The roll carriers 8.1 and 8.2 receive roll axle spigots 9.1 and 9.2,, respectively, arranged at the end faces of the grinding roll 5.1, by way of bearings (not shown). Similarly, the grinding roll 5.2.is carried by a further pair of roll carriers 10.1 and 10.2, which similarly receive roll axle spigots 11.1 and ll.',i2,r.espectively, at the end faces of the roll 5.2. The roll carriers 10.1 and 10.2 are mounted to be pivotable at pivots 12.1 and 12.2, which are provided on the carriers 8.1 and 8.2, respectively.

Fig. 4 shows another embodiment in which the pivots 12.1 and 12.2 coincide with the pivots 13.1 and 13.2. The pivots 12.1 and 12.2 can be in any suitable position along the carriers 8.1 and 8.2, but a position in the upper region is more favourable, i.e. in the immediate proximity of the grinding roll pair 5.1, 5.2, because the roll carriers 8.1 and 8.2 together with adjusting means for f ixing the relative positions of the roller carrier pairs and thus of the two rolls then form a more rigid unit. Grinding forces are short circuited by way of this unit so that they are not transmitted to the outside.

The mounting of the roll carriers 8.1 and 8.2 is effected by way of silent bushings 15.1 and 15.2 fixed in the foundation frame members 1.1 and 1.2 or by way of bearing blocks 16.1 and 16.2 connected by means of suitable vibration dampers 17.1 and 17.2 with the frame membersM and 1.2.

6 The adjusting means, for adjustment of the grinding gap 6, operates to alter the angle between the roll carrier pairs and comprises a draw spindle 14 connected to the carrier pairs at pivot points 18 and 19. The pivot points 18 and 19 are advantageously arranged above the mounting of the roll axle spigots in the roll carrier pairs. At least one of the pivot points 18 and 19 has the form of an eccentric and the grinding gap 6 is adjusted by pivotation of the roll carriers 10.1, 10.2 towards or away from the roll carriers 8.1, 8.2 through rotation of the eccent.ric. R.otation is transmitted from a lever 20 displaced by a suitable mechanicl, electromechanical, pneumatic or hydraulic drive device, in particular a piston-cylinder unit 23. The carriers 8.1, 8.2 are fixed to the wall 2 by way of a coupler 21.

By virtue of the described arrangement, all forces apart from those resulting from the grinding pressure are conducted by way of the foundation frame members 1.1 and 1.2 into the foundation 7. The dynamic and static grinding forces are absorbed within the unit of roll carrier pairs and draw spindle 14 and are not transmitted to the outside. The middle wall 7 of the frame now serves only for the fixing of the roll carriers 8.1 and 8.2 by way of the coupler 21. The side walls 22, which are situated between the end faces of the grinding rolls and the roll carrier pairs, serve only for sealing against the exit of dust and do not have to absorb any static or dynamic forces.

The vibrations resulting from the dynamic grinding forces and consequent transmission of sound through solids are damped by the bushings 15.1 and 15.2 or the dampers 17.1 and 17.2 to such an extent that there is substantially no sound transmission to the apparatus frame or to the foundation 7.

The dimensioning of the frame as well as of the side wall 22 can be such that a substantial saving of material is achieved. Moreover, the subassembly of the grinding roll pair in conjunction with the roll carrier pairs represents an easily exchangeable assembly. Maintenance becomes less complicated, since the entire unit of the grinding roll pair, roll carrier pairs and adjusting means can, after undoing the coupler 21, be tilted out by way of the bearing points 13.1 and 13.2.

A further advantage is evident from Fig. 3, in which a different arrangement of the grinding roll pair is illustrated. As already explained, the mounting method makes exchange of the grinding roll pair possible. In that case, as shown, it is quite possible to insert a grinding roll pair of a different diameter into the roll stand. In recent years, in consequence of the frequency of the milling of wheat, a grinding roll diameter of 250 millimetres has prevailed, which is not, however, optimum for the milling of rye, where diameters of more 1 than 300 millimetres are desired. Due to the smal 1 demand and the greater dimensions required with the conventional mode of construction of roll stands, roll stands with grinding roll diameters of more than 300 millimetres are no longer offered. The simple and light housing construction of apparatus embodying the present invention permits roll stands to be realised without undue technical effort with the same 1 external dimensions with a roll diameter of 250 millimetres in horizontal arrangement (Fig. 1) as well as with larger diameters in diagonal arrangement (Fig. 3). In the case of double roll stands, for example, one side can have roll diameters of 315 millimetres and the other side roll diameters of 250 millimetres without the external dimension of the roll stand housing being changed. Subsequent reequipment to a different roll diameter is also readily possible.

A further advantage is that, by virtue of the apparatus construction, favourable production conditions, as well as saving of materi a], resul t f or the manuf acturer, - s i nce the h i gh producti on accuracies required in roll stands are principally concentrated on the roll carrier pairs rather than the entire roll stand.

Claims

- 9 CLAIMS

1 Grinding roll apparatus comprising a base, a housing arranged on the base, a pair of grinding rolls arranged in the housing, mounting means mounting the rolls and adjusting means for adjusting the spacing of the rolls, the rolls, mounting means and adjusting means being removable as a unit from the housing and the mounting means comprising first carrier means carrying a first one of the rolls and mounted on the base and second carrier means carrying the second one of the rolls and pivotably mounted on pivots at the first carrier means or the base.

2. Apparatus as claimed in claim 1, the first carrier means being mounted on the base by way of bearing blocks defining mounting points.

3. Apparatus as claimed in claim 2, wherein the pivots coincide with the mounting points.

4. Apparatus as claimed in claim 2 or claim 3, the first carrier means being journalled in the bearing blocks by way of silent bushings.

5. Apparatus as claimed in any one of claims 2 to 4, wherein the bearing blocks are connected to the base by way of vibration damping means.

6. Apparatus as claimed in any one of the preceding claims, the adjusting means comprising coupling means coupling the first carrier means and the second coupling means together at respective coupling points above the rolls, and eccentric means arranged at one of the coupling points and operable to displace the first carrier means and second carrier means relative to each other.

7. Apparatus as claimed in claim 6, comprising drive means pivotably connected to one of the carrier means and drivingly coupled to the eccentric means.

8. Apparatus as claimed in claim 7, the drive means being drivingly coupled to the eccentric means by way of a lever.

9.. Grinding roll apparatus substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

10. Grinding roll apparatus substantially as hereinbefore described with reference to Fig. 3 or the accompanying drawings.

11. Grinding roll apparatus substantially as hereinbefore described with reference to Fig. 4 of the accompanying drawings.