Patent Application
20220388264
This application claims priority to German Application No. 10 2021 114 404.3, filed on Jun. 3, 2021, the entire contents of which are hereby incorporated herein by reference.
The invention relates to a new design for rollers which consist of segments, in particular for comminuting or compacting bulk material.
Bulk material is comminuted and compacted in high-pressure roller mills (roller presses) in the gap between two counter-rotating smooth rollers. Said rollers consist of a roller shaft, a roller main body (roller core), and a roller shell. If the shaft, main body, and shell are formed in one piece, this is referred to as a solid roller. If the roller shell is separate, on the other hand, this is referred to as a compound roller.
Within the meaning of the present invention, the segmented roller is defined as being formed by a roller shaft and a roller shell. The segmented roller preferably has a one-piece roller shaft. The roller core can be a separate or integral component of the roller shaft or roller shell. The roller shell is made up of segments.
Solid rollers can be manufactured as composite castings to achieve the required wear resistance. However, they usually consist of a forged part of which the surface is protected by build-up welding or grid armour (hard metal pins with a material bed formed in between as autogenous wear protection). Nevertheless, due to the low material utilisation, solid rollers are usually only used in the cement industry, where high pressing pressures, but low wear rates (e.g. 0.1-1.0 g/t), are to be expected. The use of roller presses in the ore industry, where significantly higher wear rates of e.g. 3-10 g/t occur despite lower pressing pressures, only became possible with the use of compound rollers. Drum rollers, in which the roller shell is unsegmented (“drum”) and the forged part (with grid armour using hard metal pins, sintered wear plates, or build-up welding) or cast part (white cast iron or compound cast) is designed, are widely used in this field.
However, the shells of drum rollers cannot be dismounted radially, and therefore replacing worn roller surfaces requires the entire roller to be removed and thus leads to longer downtimes (loss of production) and high replacement and mounting costs.
The following documents, which concern segmented and radially dismountable roller shells, are known from the prior art.
DE°39°27°884° A1 discloses a segmented roller with complementary projections and recesses in the adjacent radially arranged segments and the entire body and surface thereof, which result in radial toothing. These are braced together and against the roller shaft by means of clamp elements via clamping screws and tie rods, which run axially through the roller shaft. In addition, there are those arranged axially in the roller shaft. The disadvantage here is that the roller must be removed or have recesses in the housing wall of the roller crusher which allow dismounting in the installed state. The manufacturing accuracies required to manufacture the segments and the roller shaft are considerable for the feather keys to correspond to the grooves of the roller shaft and segments.
DE°197°09°263° A1 represents a further development of this document and does not have any feather keys or feather key grooves, but instead reduces the projections and recesses from the roller surface to the roller shaft and supplements them with axial rows of teeth. Similarly to the previously mentioned disadvantages, a disadvantage here is that the accuracies for producing the receptacles for the tie rods, the protruding projections for the U-shaped clip elements of the tie rods, and the manufacture of the projections and recesses of the segments relative to one another are complex and therefore expensive.
The roller in DE 3 915 320 A1 is also designed without keys and key grooves and has sawtooth-shaped recesses on the roller main body. The segments of the roller shell are fastened to the roller main body by means of fastening flanges or are clamped to the roller main body by means axial clamping screws and clamping plate segments.
DE°43°44°206° A1 discloses clamping rings which are arranged axially on both sides of the segments in order to axially interconnect and arrange a plurality of segments via axially passed-through tie rods. Furthermore, feather key grooves are provided in the roller main body or roller shaft to fix the segments radially. A disadvantage here is the manufacturing accuracy required so that the segments correspond radially to the feather keys and the feather key grooves and axially to the shoulder surfaces which as a receptacle for the clamping rings and the tie rods guided thereby.
DE°197°36°087° A1 claims a roller shaft of the dovetail feather keys that are arranged axially thereon. The associated segments have undercut dovetail guide surfaces, which are arranged on the roller shaft in a wedge shape and at an angle to the roller axis and have their maxima between two segments. The at least two segments, each at least one dovetail guide surface wedge, are bolted on and braced against the wedge relative to one another using expansion bolts. A disadvantage here is the manufacturing outlay for the production of the dovetail pairing in the form of a double wedge. In addition, it is difficult or impossible to dismount the segments with the roller installed, because the expansion bolts run through all segments and the segments have to be pulled off axially.
DE°10°2007°032°261° A1 discloses that the segments are connected to the roller shaft via intermediate elements. The intermediate elements in turn have white feather key grooves that run axially and correspond to the roller shaft. The intermediate elements are screwed onto the roller shaft and the segments are screwed onto the intermediate elements. A disadvantage is the use of the intermediate elements with the feather keys and the feather key grooves relative to the roller shaft, which makes the construction complicated and expensive. In addition, there is also the expense of the many bores and screw connections on the circumference of the roller shaft for securing the intermediate elements in place, as well as the positioning of said elements with respect to one another for inserting the screws. It is almost impossible to mount the segments in the installed state because the screws have to reach far into the segments and intermediate elements in the axial direction. The positioning the segment bores over those of the intermediate elements appears to be just as difficult.
The disadvantage of the prior art is that the disclosed segmented rollers have not been successful due to the features described and the disadvantages thereof, and the following:
The problem addressed by the present invention is therefore that of overcoming the disadvantage of the prior art.
The problem is solved by the features of the independent claims. Advantageous embodiments are specified in the dependent claims.
The invention relates to a method for mounting segments on a roller shaft, comprising the following steps:
The individual steps of the method are listed in a simplified manner. The segments can be placed, for example, by securing the segments to a hoist or by using mounting handles that then enable people to move them. The positioning takes place as a smooth transition from the setting down of the segment on top of the roller core as a further step. For optimal alignment of the segment on the roller core, positioning aids such as fitting bolts/sleeves can be used, or alignment is carried out flush via the mounting collar. A mounting collar should be understood to be a shoulder that is supported on the roller core and preferably runs completely around it. For this purpose, for example, the roller core is fixed and aligned under the relevant segment by rotation. After the positioning is complete and the relevant segment is supported in the correct position on the roller core, mounting means are arranged, for example the segments are fixed relative to the roller core by means of screws. The other segments are then attached according to the previous steps. When all segments are fixed in their position, the respective bracing elements are inserted radially. For example, one or more circumferential grooves can be provided between two or more segments. These bracing elements are preferably bracing sets which brace the segments relative to each other and with respect to the roller shaft. This bracing results in a form-fitting and frictional connection. This combination is considered to be very efficient. In practice, for example, the bracing elements are braced slightly, and the position of the segments is then checked. If the position is correct, there are no further steps to be taken and the mounting means are removed. This is followed by the final bracing of the segments and, if necessary, a final check of the position.
In a further development, the method enables the dismounting of already mounted segments from a roller shaft, comprising the following steps:
The process of dismounting segments of the segmented roller begins with arranging mounting means thereon. This secures the segments with respect to the roller core during dismounting. The bracing elements are then released, so that the bracing of the segments is released and the segments can be removed. Owing to the mounting means, the segments remain in their position on the roller core. The bracing occurred between the segments relative to one another and between the individual segments and the roller core. After the mounting means are released, they can be set down on the roller stub, for example, or removed therefrom. This is possible because the bracing elements are arranged radially on the end faces and their space requirement upon removal from the roller is small, which means that the roller does not have to be removed. Eyes for securing or mounting handles can then preferably be attached to the segment that is to be removed. Before removing a segment, the roller should be positioned in such a way that it can be removed from above or from below from the crusher or mill, for example. The roller should then preferably be secured in its position so that the relevant segment can be safely removed after the mounting means have been released and removed. This means that all segments on the roller core, or, if necessary, a single segment, can be removed therefrom.
The invention proposes a segmented roller, in particular for comminuting or compacting bulk material, comprising at least one roller shaft, at least two segments, and at least one radially arranged bracing element, the roller shaft being designed as an n-gon, in particular as a convex and/or regular n-gon, each segment being supported on the roller shaft with multiple support, and the support surfaces forming at least one common corner/transition of the roller shaft and surfaces being supported thereon.
In the broadest sense of the invention, bracing elements are understood to mean elements that have at least one conical surface and/or are designed to enable a frictional shaft-hub connection, and which can also be designed as a bracing set.
The roller shaft designed as an n-gon preferably has an n-gon cross section that runs continuously in the axial direction. The support surfaces formed in this way are distributed n times rotationally symmetrically over the circumference of the shaft. The support surfaces preferably have no structural elements such as a feather key groove, dovetail, or the like.
In embodiments of the invention, a form fit between the roller shaft of the segmented roller and the at least two segments can be achieved by multiple support across corners, this multiple support preferably being a triple support and the support surfaces being circumferentially consecutive.
Within the meaning of the invention, multiple support is understood to mean that at least two segments, preferably a plurality of segments, are arranged on the roller core, where they are supported on a plurality of support surfaces.
In embodiments of the invention of the segmented roller, the multiple support of the segments on the roller shaft is a double support, this double support resulting from at least two adjacent surfaces.
The double support is characterised by adjacent surfaces which are usually positioned at 90 degrees to each other, which results in a superposed form fit in addition to the friction fit via the bracing elements for a stronger shaft-hub connection.
In embodiments of the invention of the segmented roller, the at least one bracing element rests radially in at least one groove on the end faces of the segments. These bracing elements press the segments against the shaft core by means of a friction fit, said segments being prestressed during use.
For this purpose, the grooves can be provided in an end face so as to be circular, it being possible for the number of these grooves to vary; one groove is preferred. Other arrangements of the grooves can also be implemented, such as partial circles between individual segments, these partial circles preferably overlapping one another so that closed prestressing towards the roller core is possible. Grooves arranged on both sides in the segments and arranged symmetrically on the end faces are particularly preferred. Depending on the roller width, it is possible to install single- or multi-row bracing sets on both edges of the roller and to design the segments with appropriate wall thicknesses in order to withstand the high pressing pressures in the middle of the roller.
In embodiments of the invention of the segmented roller, the segments have mounting means on at least one end face, it being possible for these mounting means to surround the shape of the roller shaft, it also being possible for this shape to be interrupted.
Within the meaning of the invention, the mounting means (which may also be referred to herein as mounting fasteners, or individually, as mounting fastener) can be designed, for example, as screws that are carried by a mounting flange or mounting collar, without being limited thereto. The mounting means are preferably provided in one piece and circumferentially on the relevant segment. Different designs, such as interrupted, multi-part mounting means or mounting collars, are conceivable.
The mounting means rest on the roller core or are very slightly spaced therefrom. They are used for easy mounting/dismounting of the segments on the roller core.
In embodiments of the invention, the mounting means are detachably or non-detachably connected to the relevant segment.
These mounting means on the segments, preferably designed as mounting flanges, are detachably connected, preferably screwed, thereto. They can also be non-detachably connected, for example welded or forged on.
In embodiments of the invention, the mounting means of the segmented roller have openings for the detachable arrangement of the segments on the roller shaft.
The segment is thus connected to the shaft via screws during mounting/dismounting and thereby secured.
In embodiments of the invention of the segmented roller, the segments have variable dimensions and material thicknesses, said segments being made of different materials and material combinations.
These materials are preferably metallic, such as cast or forged materials, and particularly preferably steels and alloys thereof. Within the meaning of the invention, composite materials and sintered materials are understood to mean a combination of materials, without being limited thereto.
In embodiments of the invention of the segmented roller, it is formed integrally by the roller shaft and roller core. This roller shaft thus has connections and roller cores which are integral components of the roller shaft. In a further embodiment of the invention, the components are designed to be partially integral and, for example, the roller core is shrunk onto the shaft with the connections.
A further aspect of the invention relates to the use of a method according to the invention for mounting and/or dismounting a segmented roller according to the invention.
Another aspect of the invention is the use of a segmented roller according to the invention using a method according to the invention.
In one of the claimed embodiments, the claimed method and/or the segmented roller prevent the erosion of screw bores in the case of radial fastening, because these can advantageously be dispensed with: if the segments are screwed radially to the main body, they can be dismounted without removing the rollers. However, due to the high pressing pressures, the counterbores are eroded. If the segments are only screwed to the roller edge, this in turn leads to insufficient support for the segments.
The disadvantages of the prior art are overcome by the claimed method and/or the segmented roller.
The invention will be explained in greater detail below with reference to an embodiment. The embodiment is intended to describe the invention without limiting it.
In the drawings:
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 114 404.3 | Jun 2021 | DE | national |
