GB2187658A

GB2187658A - Apparatus for dismounting rollers in a vertical roller mill

Info

Publication number: GB2187658A
Application number: GB08705566A
Authority: GB
Inventors: Ottmar Bacharach; Manfred Albus; Lothar Dickert
Original assignee: Gebr Pfeiffer AG
Current assignee: Gebr Pfeiffer AG
Priority date: 1986-03-12
Filing date: 1987-03-10
Publication date: 1987-09-16
Anticipated expiration: 2007-03-10
Also published as: DE3608192C2; GB8705566D0; GB2187658B; DE3608192A1; DK119287D0; DK119287A; DK171195B1

Abstract

A mounting aperture (9), which can be closed by a door (10), is provided in the mill housing (1) for the purpose of dismounting and mounting the crushing rollers (5) of a vertical roller mill. In front of this mounting aperture (9), a vertical shaft (14) is mounted by means of a bracket (11) and upper and lower sliding-pivot bearings (15,16) and at its bottom end this shaft (14) is provided with a hydraulic cylinder (19). By means of a lifting bracket (17) and retaining means (18) a secure three-point mounting is established between the shaft (14) and the crushing rollers (5). After lifting the auxiliary structure by means of the hydraulic cylinder (19), the crushing roller (5) can be swung out of the mill housing (1) through the aperture (9) and attached to an overhead crane (20). Remounting of the crushing roller (5) is carried out correspondingly in reverse order. <IMAGE>

Description

SPECIFICATION Apparatus for dismounting rollers in a vertical roller mill The invention relates to an apparatus for dismounting and mounting grinding or crushing rollers in a vertical roller mill, which have stationary crushing rollers arranged to roll on a rotary crushing pan and rotatably supported by roller retaining means, pressure means pressed on to the crushing rollers byway of tie rods, devices for supporting the crushing rollers on the crushing pan during mounting or maintenance, and a housing aperture which can be closed by a door and through which the crushing rollers can be dismounted or mounted.

Since the crushing rollersaresubjecttowearin operation all mills have devices which enable the crushing rollers to be dismounted and remounted.

In the simplest instance, a sifter or separator disposed on the mill housing is removed, for example, by means of an overhead crane and set down nearto the mill housing. The dismounting and mounting ofthe crushing rollers is then carried out from above by means of the crane.

Other mills have special rails along which the separator can be displaced by means of an undercarriage (DE journal "Aufbereitungs-Technik", No.9/1971, page 545, Figure 23).

In another known construction, the separator is attached by its own undercarriage to the rails of a overhead crane and can thus travel laterally (Patent Specification DE-OLS 2641620).

The disadvantage with these known devices is that the air-tight connections between the separator and mill housing orseparatorand exhaust airduct have to be loosened,the separatortogetherwith all components attached thereto shifted laterally and the means pressing the crushing rollersontothe crushing pan completely dismounted.

Anotherknown mill has large openings in the mill housing, on the upper side of which an individual crane track is introduced into the mill housing. The crushing rollers can be attached to this crane track and, when necessary, they can be moved outofthe mill (DE journal "Zement-Kalk-Gips", No.12/1985, page 705).

In yet another mill in use for many years, the crushing rollers can be swung outthrough a respective side door provided in the mill housing.

For this purpose they are supported on a respective hydraulic hinge device with a horizontal hinge axis.

The disadvantage with this is that a separate hinge device for each crushing roller is necessary, which increases the cost of the plant, entails sealing problems and requires an adequate amount of space around the mill (DEjournal "Aufbereitungs-Technik", No.9/1971, page 545, Figure 24).

Patent Specification EP-A 110535 discloses anotherapparatusinwhichthecrushing rollersare raised by means of a first cable incorporated in the mill and separator housing and they are removed through a special mounting aperture by means of an overhead crane. This construction is extremely dangerous because the supporting cables become kinked here and they chafe on the mill housing so that damage is inevitable. Depending on the size of the mill, a crushing rollerweighsseveraltonnes.

The subject of the present invention is an apparatus of the type mentioned atthe beginning, which allows all the crushing rollers to be dismounted and mounted through a single mounting aperture, of the smallest size possible, which and at the same time is simple, inexpensive and yet reliable in operation.

According to the invention belowthe door a bracket is provided externally on the housing, an upstanding shaft is provided which can be rotatably supported on the bracket and at its top and bottom ends can be secured to the housing above and below the door by respective sliding-pivot bearings, a lifting bracket and a retaining means are attached to the shaft whereby a secure and releasable connection to the roller retaining means can be effected, and a lifting device is provided atthe bottom end of the shaft.

This offers the advantages thatthe single mounting door can be kept relatively small, sincethe crushing roller can be swung edgeways out of the housing; that the seal between the relatively small door and the mill housing can be of correspondingly simple and reliable design; that on the mill housing itself onlythe bracket and securing facilities forthe sliding-pivot bearings have to be permanently provided, and thatthe entire apparatus can be very reliable in operation, despite its simplicity.

Preferably, a central column can be set up in the centre of the crushing pan, a mounting spider with lateral arms is secured to the head of the central column, and the connection between the arms and the roller retaining means is effected by cotter pins.

This construction prevents the crushing rollers from tipping overwhen the pressure means is raised,which mostsimply is effected by means of the tie rods normally exerting a downwardtension on the pressure means (Patent Specification DE-OS 3106546). The connection between the mounting spider and the roller retaining means by cotter pins is simple and therefore entirely secure. As soon as the crushing rollers and/ortheir retaining means are connected to the central column, they can be moved successively in front of the mounting aperture by slowly rotating the crushing pan.

Preferably the central column in the crushing pan can be lowered.

This is a simplification in construction which also allowsthemounting operationstobedonequickly.

In the accompanying drawings: Figure lisa cross-section through a vertical roller mill, in the operating position; Figure2 is a section through the mill according to Figure 1 taken along the line ll-ll; Figure 3 is a cross-section through the mill according to Figure 1, with a dismounted crushing roller; and Figu-re4isasectionthroughthe mill according to Figure 3, taken along the line IV-IV.

Figures 1 and 2 show a mill housing 1 of a vertical rollermill,ontheupperendofwhich aseparator2is mounted in conventional manner. In the lower part of the mill housing 1 there is disposed a transmission 3 which drives a crushing pan 4. Three crushing rollers 5 are arranged to roll on the crushing pan 4.

These crushing rollers 5 are supported stationarily by roller retaining means 6 and are pressed on to the crushing pan 4 by way of a common pressureframe 7 by means of tie rods 8 which are anchored to the mill base.

Amounting aperture 9 isvisible on the right-hand side ofthe mill housing 1 and it is closed and sealed buy a door 10 during a crushing operation.

Belowthe door 10 a bracket 11 is provided externally on the mill housing 1.

In the centre of the crushing pan 4, there is a central column 12which is lowered during a crushing operation,which is partofthe apparatus for dismounting and mounting the crushing rollers 5.

Figures 3 and 4 showthe mill during the dismounting of one of the crushing rollers 5. By extending the tie rods 8, the pressure frame 7 is raised from the crushing rollers 5 and from the roller retaining means 6. The central column 12 is extended upwards so asto preventthecrushing rollers 5 from tipping over and it carries a mounting spider 13 with three arms. The ends of the arms of the mounting spider 13 are connected to the roller retaining means by means of cotter pins 21.

As shown particularly in Figure 4, the door 10 is open. Avertical shaft 14 is disposed on the bracket 11 and is secured to the mill housing 1 by respective upperand lowersliding-pivotbearings 15and 16.A lifting bracket 17 engaging underthe roller retaining means 6 is secured to the shaft 14. Additional retaining means 18 are provided engaging the shaft 14and the roller retaining means 6, so as to establish a stablethree-point mounting ofthe roller retaining means 6 on the shaft 14.

A hydraulic cylinder 19 is provided as a lifting device atthe bottom end ofthe shaft 14. As soon as the connection is made between the shaft 14 and the crushing roller5 brought in front ofthe mounting aperture 9, the crushing roller 5 is raised by means of the hydraulic cylinder 19 and can then be swung freely out of the mounting aperture 9. Since the crushing roller5 is here swung with its edge or rim through the aperture 9, the size ofthe aperture 9 can be kept relatively small.

As soon as the roller 5 has been swung fully out, it can be lifted by means of a cable 20, by an overhead crane, and transported away.

If further crushing rollers 5 are to be dismounted, they are moved in front of the single mounting aperture 9, by slowly rotating the crushing pan 4 because of the secure connection with the central column 12 by way ofthe mounting spider 13 and dismounted in the manner described.

The mounting of crushing rollers is carried out correspondingly in reverse order.

Claims

1. An apparatus for dismounting and mounting grinding or crushing rollers in avertical roller mill, which has stationary crushing rollers arranged to roll on a rotary crushing pan and rotatably supported by roller retaining means, pressure means pressed on to the crushing rollers by way of tie rods, devices for supporting the crushing rollers on the crushing pan during mounting or maintenance, and a housing aperture which can be closed by a door and through which the crushing rollers can be dismounted or mounted, wherein belowthe door a bracket is provided externally on the housing, an upstanding shaft is provided which can be rotatably supported on the bracket and at its top and bottom ends can be secured to the housing above and below the door by respective sliding-pivot bearings, a lifting bracket and a retaining means are attached to the shaft, whereby a secure and releasable connection to the roller retaining means can be effected, and a lifting device is provided at the bottom end ofthe shaft.

2. An apparatus as claimed in Claim 1, wherein a central column can be set up in the centre ofthe crushing pan, a mounting spider with lateral arms is secured to the head ofthe central column, and the connection between the arms and the roller retaining means is effected by cotter pins.

3. An apparatus as claimed in Claim 2, wherein the central column in the crushing pan can be lowered.

4. An apparatus as claimed in Claims 1,2 or 3, wherein the lifting device is a hydraulic cylinder.

5. Apparatus substantially as herein described with reference to and as shown in the accompanying drawings.