Patent ID: 12241203

For the sake of clarity, the figures show some embodiments of the invention in a simplified manner. Like reference numerals identify like elements in the figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG.1is a schematic general side view of a general construction of a refiner1in cross-section, which refiner may be used for refining a fibrous material, such as a wood material containing lignocellulose or another fiber material suitable to be used for manufacturing paper or paperboard, for example. The refiner1shown inFIG.1is of conical type but disc-refiners, conical-disc-refiners and cylindrical refiners could be used as well as an example here. Generally, a refiner comprises at least two substantially oppositely positioned refining elements at least one of which is rotating, and a refining chamber formed between each two substantially oppositely positioned refining elements. In the following a refiner with only one rotatable refining element is described.

The refiner1ofFIG.1comprises a frame2and a stationary, fixed refining element3, i.e., a stator3, supported on the frame2. The stator3comprises two or more stator blade segments4, each of them comprising blade bars and blade grooves therebetween. The blade bars and the blade grooves in each stator blade segment4form a refining surface5of the respective blade segment4, the refining surface5of each stator blade segment4thereby providing a part of a refining surface of the stator3. A complete refining surface of the stator3is formed of the refining surfaces5of a necessary number of the blade segments4fastened next to each other in the stator3so that the complete refining surface5extending over the whole circumference of the stator3is provided. For the sake of clarity, both the refining surface of each single stator blade segment4as well as the complete refining surface of the stator3are herein denoted with the same reference sign5.

The refiner1further comprises a rotatable refining element6, i.e., a rotor6, of the refiner1. The rotor6comprises a hub7. The rotor6further comprises two or more rotor blade segments8supported to the hub7, each rotor blade segment8comprising blade bars and blade grooves therebetween. The blade bars and the blade grooves in each rotor blade segment8form a refining surface9of the respective blade segment8, the refining surface9of each rotor blade segment8thereby providing a part of a refining surface of the rotor6. A complete refining surface of the rotor6is formed of the refining surfaces9of a necessary number of the blade segments8fastened next to each other in the rotor6so that the complete refining surface9extending over the whole circumference of the rotor6is provided. For the sake of clarity, both the refining surface of each single rotor blade segment8as well as the complete refining surface of the rotor6are herein denoted with the same reference sign9.

The hub7of the rotor6is connected to a driving motor10by a shaft11so that the rotor6can be rotated relative to the stator3in a direction of arrow RD, for instance, the arrow RD thus indicating an intended rotation direction RD of the rotor6.

The refiner1may also comprise a loading device which, for the sake of clarity, is not shown inFIG.1. The loading device can be used for moving back and forth the rotor6attached to the shaft11, as schematically shown by arrow A, in order to adjust a size of a refining gap12, i.e., a refining chamber12, between the stator3and the rotor6, wherein the fibrous material is actually refined.

The fibrous material to be refined is fed into the refiner1via a feed channel13in a manner shown by arrow F. In one embodiment most of the fibrous material fed into the refiner1passes, in a manner schematically shown by arrows P, through openings14formed in the rotor blade segments8into the refining chamber12, wherein the fibrous material is to be refined. Furthermore, most of the already refined fibrous material is, in turn, discharged through openings15formed in the stator blade segments4into an intermediate space16between the frame2of the refiner1and the stator3, wherefrom the refined material is removed via a discharge channel17from the refiner1, as schematically shown by arrow D.

Since the space between the rotor6and the frame2of the refiner1ofFIG.1is not fully closed, some of the fibrous material to be fed into the refiner1may transfer into the refining chamber12from the right end of the refilling chamber12, i.e., from a first end18or an inner end18of the refiner1having a smaller diameter, as seen inFIG.1. Correspondingly, some of the already refined material may also exit the refining chamber12from the left end of the refining chamber12, i.e., from a second end19or an outer end19of the refiner1having a larger diameter, as seen inFIG.1, wherefrom a connection is provided to the intermediate space16.

In the embodiment ofFIG.1of the refiner1, only one feed channel13is provided, and it is arranged at the first end18of the refiner1having the smaller diameter. The actual implementation of the refiner could also comprise a second feed channel arranged at the second end19of the refiner1having the larger diameter, whereby the discharge channel17of the refiner1could be arranged for example somewhere between the first18and second19ends of the refiner1. In the following, the reference sign18and the term first end18or the term inner end18may indicate both the first end18or the inner end18of the refiner1having the smaller diameter and the first end18or the inner end18of the refining elements3,6or of the refining chamber12having the smaller diameter. Correspondingly, the reference sign19and the term second end19or the term outer end19may indicate both the second end19or the outer end19of the refiner1having the larger diameter and the second end19or the outer end19of the refining elements3,6or of the refining chamber12having the larger diameter.

It is emphasized that in addition to the conical refiner disclosed above the blade segment of the solution described herein may be applied in other kinds of conical refiners too. In addition to conical refiners the blade segment of the solution described herein is applicable to disc refiners and cylindrical refiners and to refiners comprising both a conical portion and a disc portion, as well.

FIG.2is a schematic planar upper view of a blade segment4,8applicable to be used for forming a part of the refining surface5,9of the stator3or the rotor6, whereby the complete refining surface5,9is provided by arranging the necessary number of the blade segments4,8ofFIG.2next to each other around a circumference of the stator3or the rotor6.FIG.3is a schematic planar upper view of a set of two neighboring blade segments4a,4b,8a,8bhaving the implementation corresponding to the blade segment4,8ofFIG.2,FIG.3depicting the way the blade segments4,8are mounted in a respective stator3or rotor6.

The blade segment4,8comprises an inner end edge20or a first end edge20to be directed towards the inner end18of the refining element3,6having the smaller diameter. The blade segment4,8further comprises an outer end edge21or a second end edge21to be directed towards the outer end19of the refining element3,6having a larger diameter. The blade segment4,8has a longitudinal axis extending from the inner end edge20to the outer end edge21and a width direction transversal to the longitudinal axis, the longitudinal axis of the blade segment being shown schematically by an arrow LA. When mounted in a refiner the longitudinal axis LA provides an axial direction of the refiner in the case of conical and cylindrical refiners and a radial direction of the refiner in the case of disc refiners.

The blade segment4,8further comprises a first side edge22or a leading side edge22extending from the inner end edge20of the blade segment4,8up to the outer end edge21of the blade segment4,8and providing the side edge of the blade segment4,8which is the first to meet an edge of a counter blade segment during rotation of the rotor6, thus it provides the side edge of the blade segment to be directed towards the intended rotation direction RD of the rotor6. The blade segment4,8further comprises a second side edge23or a trailing side edge23opposite to the first side edge22in the width direction of the blade segment4,8. The second side edge23extends from the inner end edge20of the blade segment4,8up to the outer end edge21of the blade segment4,8and provides the side edge of the blade segment4,8which is the last to meet the edge of the counter blade segment during rotation of the rotor6, thus it provides the side edge of the blade segment to be directed towards the direction that is opposite to the intended rotation direction RD of the rotor6. The inner20and the outer21end edges together with the first22and second23side edges define a periphery of the blade segment4,8.

The blade segment4,8comprises a body24having a front surface25to be directed towards the refining chamber12of the refiner1and a background or rear surface26to be directed towards the hub7of the rotor6, as shown for example inFIG.5. The front surface25of the blade segment body24is provided with blade bars27and blade grooves28which together provide the refining surface5,9of the blade segment4,8. The blade bars27are intended to defiber and refine the material to be refined and the blade grooves28are intended to convey the material to be refined forward along the refining surface5,9.

The blade segment of the solution disclosed herein comprises an opening14,15at least on one side edge22,23thereof. The opening14,15may have the form of an indent as schematically shown inFIGS.2and3, or a continuous slit or bay as schematically shown inFIG.4.

In the blade segment4,8ofFIG.2, there are openings14,15on the first side edge22of the blade segment4,8. The opening14,15extends from the first side edge22towards the opposite second side edge23so that the opening14,15has a dimension both in the direction of the longitudinal axis LA and a dimension in the width direction of the blade segment3,8. In other words, there is at least one opening14, i.e., one or more openings14, at the first side edge22of the blade segment4,8such that the first side edge22does not form a completely straight line between the inner end edge20and the outer end edge21. The openings14,15extend from the front surface25of the blade segment body24up to the rear or background surface26of the blade segment body24, the openings14thus extending through a whole thickness of the blade segment4,8or the blade segment body24.

FIG.2shows an embodiment of the blade segment4,8with four openings14at the first side edge22of the blade segment4,8. Alternatively, the blade segment4,8may comprise at the second side edge23one or more openings14that extend(s) from the second side edge23towards the opposite first side edge22such that the second side edge23does not form a completely straight line between the inner end edge20and the outer end edge21.

FIG.4shows schematically an upper oblique view of a part of a set of another neighboring blade segments8a,8bas applied in a rotor6of a conical refiner1. The blade segments8a,8bofFIG.4comprise shoulder members32,33,34,35in proximity of corners of the blade segment8a,8b, i.e., a shoulder member32at the first end edge20of the blade segment8a,8bon the side of the first side edge22, a shoulder member33at the first end edge20of the blade segment8a,8bon the side of the second side edge23, a shoulder member34at the second end edge21of the blade segment8a,8bon the side of the first side edge22and a shoulder member35at the second end edge21of the blade segment8a,8bon the side of the second side edge23. The shoulder member32,33,34,35is intended to come into contact with a corresponding shoulder member in a neighboring blade segment when assembled to provide a part of a refining surface of a refining element of a refiner.FIG.4also shows schematically fastening holes36intended to receive fastening means, like bolts, for fastening the blade segment to the hub7of the rotor6, or any supporting structures directly or via supporting means, like fixing rings37.

Between the shoulder members32,34on the first side edge22of the blade segment8a,8bthe first side edge22comprises a number of longer edge portions22aconnected by elbows22btherebetween, i.e., there is the elbow22bbetween two successive longer edge portions22a. The longer edge portions22aand the elbows22bare arranged to deviate from the direction of the longitudinal axis LA of the blade segment8a,8bsuch that a substantially continuous slit-like or bay-like opening14is arranged at the first side edge22of the blade segment8a,8b.

In the embodiment ofFIG.4the longer edge portions22aare arranged to deviate to the same direction with respect to the direction of the longitudinal axis LA and the elbow22bis turned away from the longer edge portions22ato deviate with respect to the direction of the longitudinal axis LA in a different direction than the longer edge portions22abut other mutual implementations of the longer edge portions22aand the elbows22bare also possible.

Similar longer edge portions and elbows as disclosed above may also be applied on the second side edge23of the blade segment23, whereby the slit-like or bay-like openings14on the first side edge22and/or the second side edge23of the blade segments8a,8bprovide the substantially continuous slit-like or bay-like openings14, having a form of a kind of zig-zag, between the neighboring blade segments8a,8bin the rotor6.

Similar construction of the blade segments as disclosed inFIG.4and the related description may also be applied in the stator3of the refiner1correspondingly.

The embodiments of the blade segments4,4a,4b,8,8a,8bofFIGS.2and3and the blade segments8a,8bofFIG.4further comprise feed grooves29. A more detailed discussion about the feed grooves29is disclosed later in this description.

Referring toFIGS.3and4showing schematically planar upper views of a set of two neighboring blade segments4a,4b,8a,8b, i.e., a first blade segment4a,8aand a second blade segment4b,8b, it can be seen that the openings14,15in the first blade segment4a,8aremain between the first side edge22of the first blade segment4a,8aand the second side edge23of the neighboring second blade segment4b,8b. In other words, the walls14a,14b,15a,15bof an opening14,15are formed by the side edges22,23of two neighboring blade segments4a,4b,8a,8bsuch that the first side edge22of the first blade segment4a,8aforms or provides a first wall14a,15aa of the opening14,15at each opening14,15and the second side edge23of the second blade segment4b,8bforms or provides a second wall14b,15bof the opening14,15at each opening14,15. InFIG.3the openings14,15have the form of an indent and inFIG.4the openings14have the form of continuous slits or bays.

FIG.5is a partial schematic cross-sectional end view of a first embodiment of the blade segments8,8a,8bofFIGS.2,3and4along the cross-sectional lines A-A shown inFIGS.3and4. The feed groove29is omitted inFIG.5. Further it should be noted that even inFIG.5, as well as later inFIGS.6and7, the construction of the blade segment is disclosed in view of the rotor blade segment, similar construction of the blade segment is applicable also for the stator blade segment.

In the embodiment ofFIG.5there is arranged a projection30in the background or rear surface26at the first side edge22of the blade segment8,8a,8bat least at each opening14of the blade segment8,8a,8b. In other words, the blade segment8,8a,8bcomprises in the background surface26of the blade segment body24the projection30at the first wall14aof at least each opening14. The projection extends substantially beyond the rear plane of the blade segment, i.e., in the rotor6substantially towards a center of the rotor6when the blade segment8,8a,8bis to be installed to the rotor6. The projection30may also extend over the whole longitudinal length of the blade segment8,8a,8bbut the projection30extends at least substantially over the longitudinal extension of the opening14, and preferably at least at each opening14of the blade segment8,8a,8b.

In the embodiment ofFIG.5the projection30is a solid part of the body24of the blade segment8,8a,8b. Alternatively, the projection30could be a separate part that is welded, soldered or in some other manner fastened to the body24of the blade segment8,8a,8b.

The projection30disclosed provides on the side of the background or rear surface26of the blade segment8,8a,8ba height difference between the background surface26at the first side edge22of the blade segment8,8a,8band the background surface26at the second side edge23of the blade segment8,8a,8bat the opening14, and preferably at least at each opening14, of the blade segment8. In other words, the projection30disclosed provides at the opening14on the side of the background surface26of the blade segment8,8a,8ba height difference between the background surface26at the first wall14aof the opening14and the background surface26at the second wall14bof the opening14, and preferably at least at each opening14, of the blade segment8.

The height difference between the background surface26at the first side edge22and the background surface26at the second side edge23of the blade segment8,8a,8bis considered in respect of a reference level provided by a level or plane of the background surface26the blade segment8,8a,8bnot taking into account possible protrusions in the body24of the blade segment8,8a,8bintended for example for supporting the blade segment8,8a,8bto the hub7of the rotor6or cavities or pockets in the body24of the blade segment8,8a,8bintended to lighten a structure of the body24of the blade segment8,8a,8b.

The height difference provided by the projection30forms on the side of the background surface26of the blade segment8,8a,8ba wing-like structure or a guide element or a guide surface that during operation of the refiner intensifies the feed of the material to be refined through the opening14from the background surface26side of the blade segment to the front surface25side of the blade segment, i.e., to the refining surface9of the blade segment8,8a,8bor into the refining chamber12between the stator3and the rotor6by guiding the flow of material towards the opening14. The feed direction of the material to be refined inside the rotor6is shown schematically with an arrow FI.

The improved flow of the material to be refined into the refining chamber12has the effect that the material to be refined does not plug the openings14, which, in turn, has the effect that the overall refining result is more constant. Furthermore, the operating pressure of the refiner is maintained better such that there is higher pressure after the refiner than previously, which provides higher capacity in the refining. The higher capacity to be achieved means also that the same capacity as earlier may be obtained even if an open area of the opening14would be reduced. This, in turn, makes it possible to increase a cutting-edge length of the blade bars27of the blade segment8,8a,8bfor improving especially hardwood refining.

According to an embodiment, at least one side edge of the blade segment is at least on a portion of its thickness direction inclined towards or away from the neighboring wall14a,14bat the opening14of the blade segment. According to this embodiment, the first side edge22of the blade segment8,8a,8b, i.e., the first wall14aof the opening14, and/or the second side edge23of the blade segment8,8a,8b, i.e., the second wall14bof the opening14, are/is at least on a portion of its thickness direction inclined at least at the opening(s)14of the blade segment8,8a,8b.

In the embodiment ofFIG.4, both the first side edge22of the blade segment8,8a,8band the second side edge23of the blade segment8,8a,8bare inclined on their thickness direction such that the rear surface corner of the first side edge22extends farther towards the intended rotation direction RD of the rotor6, i.e., farther from the second side edge23of the blade segment8,8a,8bthan the front surface corner, and the rear surface corner of the second side edge23extends farther towards the intended rotation direction RD of the rotor6, i.e., farther towards the first side edge22of the blade segment8,8a,8bthan the front surface corner of the second side edge23. This inclination of the walls14a,14bof the opening(s)14has the effect of improving the feed of the material to be refined through the openings14into the refining chamber12between the stator3and the rotor6when the refiner1is in use.

According to an embodiment the side edges of the blade segment are at least on a portion of their thickness direction inclined at substantially different angles from each other at least at each opening of the blade segment. According to this embodiment, the first side edge22of the blade segment8,8a,8b, i.e., the first wall14aof the opening14, and the second side edge23of the blade segment8,8a,8b, i.e., the second wall14bof the opening14, are at least on a portion their thickness direction inclined at substantially different angles from each other at least at each opening14of the blade segment8,8a,8b.

According to this embodiment the inclination angle of the first side edge22and the inclination angle of the second side edge23of the blade segment8,8a,8bare at least on a portion of the thickness direction of the side edges22,23different from each other at least at each opening14of the blade segment8,8a,8b, thus deviating from the embodiment ofFIG.5, wherein the side edges22,23are inclined at substantially equal angles. The embodiment disclosed herein includes also the embodiment wherein only one of the side edges22,23of the blade segment8,8a,8bis inclined relative to the normal of the refining surface9of the blade segment8,8a,8b.

The effect of this embodiment is a change in a cross-sectional open area of the opening14along at least a portion of the wall14a,14b. This provides further means to affect the flow of the material to be refined through the opening14into the refining chamber12.

According to an embodiment at least one side edge of the blade segment is curved at least on a portion of its thickness direction at least at each opening of the blade segment. According to this embodiment, the first side edge22of the blade segment8,8a,8b, i.e., the first wall14aof the opening14, and/or the second side edge23of the blade segment8,8a,8b, i.e., the second wall14bof the opening14, are/is at least on a portion of its thickness direction curved at least at each opening14of the blade segment8,8a,8b.

In the embodiment ofFIG.6, showing a partial schematic cross-sectional end view of a second embodiment of the blade segments8,8a,8bofFIGS.2,3and4along the cross-sectional lines A-A shown inFIGS.3and4, and omitting the feed groove29, both the first side edge22and the second side edge23of the blade segment8,8a,8bare like the walls14a,14bofFIG.5with the exception that they are curved on their thickness direction.

This curved arrangement of the blade segment side edges22,23inFIG.6also provides inclination of the walls14a,14bof the openings14having the effect of providing a smooth guidance for the pulp and thus improving its feed through the opening(s)14into the refining chamber12between the stator3and the rotor6when the refiner1is in use.

FIG.7is a partial schematic cross-sectional end view of a third embodiment of the blade segments8,8a,8bofFIGS.2,3and4along the cross-sectional lines A-A shown inFIGS.3and4. The feed groove29is omitted also inFIG.7.

In the embodiment ofFIG.7there is arranged a bevel31in the background surface26at the second side edge23of the blade segment8,8a,8bat least at each opening of the blade segment8,8a,8b. In other words, the blade segment8,8a,8bcomprises in the background surface26of the blade segment body24the bevel31at the second wall14bof at least each opening14. The bevel31extends from the second side edge23of the blade segment8,8a,8bsubstantially towards the intended rotation direction RD of the blade segment8,8a,8bwhen the blade segment8,8a,8bis installed to the rotor6, or in other words, towards the first side edge22of the blade segment8,8a,8b. The bevel31may also extend over the whole extension of the second side edge23of the blade segment8between the inner end edge20and the outer end edge21of the blade segment8,8a,8bbut the bevel31extends at least substantially over the extension of the opening14in the direction between the inner end edge20and the outer end edge21of the blade segment8,8a,8b.

The bevel31may for example be formed by removing the material of the blade segment8,8a,8bon the side of the background surface26at the second side edge23of the blade segment8,8a,8bat least at each opening14. According to another example, the bevel31may be formed by excluding the material of the blade segment8,8a,8bon the side of the background surface26at the second side edge23of the blade segment8,8a,8bat least at each opening14.

The bevel31also provides on the side of the background surface26of the blade segment8,8a,8bthe height difference between the background surface26at the first side edge22of the blade segment8,8a,8band the background surface26at the second side edge23of the blade segment8,8a,8bat least at each opening14of the blade segment8,8a,8bsuch that the first side edge22of the blade segment8,8a,8bextends farther towards the direction where the background surface26of the blade segment8,8a,8bfaces to than the second side edge23of the blade segment8,8a,8b. Similarly to the embodiments ofFIGS.5and6, the height difference provided by the bevel31forms on the side of the background surface26of the blade segment8,8a,8b, at the first side edge22of the blade segment8,8a,8bat least at the opening14, a guide element or a guide surface that intensifies the feed of the material to be refined from the background surface2.6side of the blade segment8,8a,8bthrough the opening14to the front surface25side of the blade segment8,8a,8b, i.e., to the refining surface9of the blade segment8,8a,8bor into the refining chamber12between the stator3and the rotor6.

Referring back to the feed groove29andFIGS.2,3and4, the feed groove29is arranged to extend from the opening14arranged in the first side edge22of the blade segment4,4a,4b,8,8a,8btowards at least one other edge of the blade segment, towards the second side edge23of the blade segment, such that the feed groove29crosses the blade bars27and the blade grooves28. The feed groove29has a first end29aat the opening14and a second end29bfacing away from the opening14. The feed groove29, together with the respective indent- or slit-like opening14at the first side edge22, forms a flow connection so that the material to be refined and supplied from the side of the background surface26of the blade segment towards the front surface25of the blade segment through the opening14enters into the feed groove29and flows along the feed groove29towards a central portion of the blade segment, thus feeding the material to be refined across the refining surface5,9. At the same time, forces being caused by the rotation of the rotor6act on the material flowing in the feed groove29and force the material away from the feed groove29into the blade grooves28remaining between the blade bars27, and onto top surfaces of the blade bars27, thus distributing the material to be refined on the refining surface of the blade segment. It is to be noted that the feed groove29is not an essential feature of the blade segment but a feature that may be utilized in some embodiments of the blade segment to improve the distribution of the material to be refined on the refining surface of the blade segment.

In the embodiment of the blade segment ofFIGS.2,3and4, the feed groove29is arranged to cross the blade bars27and the blade grooves28at an angle. According to this embodiment, the feed groove29crosses the blade bars27and the blade grooves28at an angle that is preferably from 90 to ±45 degrees. The effect of this embodiment is a better distribution of the material to be refined from the feed groove29into the blade grooves28and onto the top surfaces of the blade bars27, i.e., into the refining chamber12.

According to an embodiment of the blade segment, the feed groove is curved along its direction of extension. The second end of the curved feed groove may be either at a same or a different position in the longitudinal direction of the blade segment, denoted by the longitudinal axis LA of the blade segment than the first end of the feed groove. The advantageous effect of this embodiment is that the material to be fed onto the refining surface of the blade segment may be directed substantially freely at desired portions of the refining surface.

Referring back to the feed groove29and the embodiment ofFIG.4, the blade bars27of the blade segment8a,8bare interlaced at the feed groove. The blade bars27are interlaced at the feed groove29such that the ends of the blade bars on opposite sides of the feed groove, as seen in the direction of the longitudinal axis LA of the blade segment, are interlaced at the feed groove29.

According to an embodiment into opposite directions directed interlaced ends of the interlaced blade bars comprise downwards descending sloping ends arranged to form the feed groove opening upwards.

The interlacing of the blade bars at the feed groove provides at the feed groove a strong blade bar configuration wherein the interlaced blade bars give support to each other, thereby preventing a buckling of the blade bars at the feed groove.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.