瑞典专利SE1551300A1 Feeding center plate in a pulp or fiber refiner

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专利摘要:
21 ABSTRACT A center plate (10) for a rotor (6) in a pulp or fiber refiner (1) has a surface(200) provided With at least one feeding Wing (100) for directing lignocellulose-containing material (7) ﬂoWing onto the surface (200) towards a periphery ofthe center plate (10). The at least one feeding Wing (100) is an elongatedprotrusíon arranged such that a second end (l00b) of the feeding Wing (100)is arranged further away from a center of the center plate (10) than a first end(l00a) and is also displaced relative to the first end (l00a) in a directionopposite to a direction of rotation (11) of the rotor (6) and center plate ( 10).The at least one feeding Wing (100) is provided With at least one opening (101)allowing steam (810) to ﬂoW through the opening or openings (101) in adirection having a component directed opposite to the direction of rotation (1 1), When the center plate (10) is rotating in the direction of rotation (1 1). (Fig. 5)
公开号:SE1551300A1
申请号:SE1551300
申请日:2015-10-08
公开日:2017-04-09
发明作者:Lindblom Thommy
申请人:Valmet Oy；
IPC主号:

专利说明:

F EEDING CENTER PLATE IN A PULP OR FIBER REFINER TECHNICAL FIELD The present invention generally relates to refining of lignocellulose-containingmaterial, and more particularly to a center plate for a rotor in a pulp or fiberrefiner, as well as a pulp or fiber refiner with a rotor comprising such a center plate.
BACKGROUN D A commonly used pulp or fiber refiner comprises a rotor unit and a stator unit(or alternatively, two rotor units) that are aligned along a common axis andfacing each other, for grinding lignocellulose-containing material, such aswood chips, into pulp. The refining of the pulp/ fiber is performed in a boundedarea between the rotor unit, or rotor, and the stator unit, or stator. Fig. l is aschematic illustration of a part of an ernbodirnent of a pulp/ fiber refiner 1viewed from above. During use of the pulp / fiber refiner 1 of Fig. 1lignocellulose-containing material 7, such as wood chips, is fed into thepreheater 2. Steam 8 is input at the bottom of the preheater 2 and goesupwards through the pile of wood chips. The wood chips are discharged fromthe preheater 2 by a discharge screw 2a and fed into a feed screw Sa whichfeeds the chips via a feeding channel 3 towards the defibrator 4. The woodchips are fed by the feed screw Sa through a hole in the stator 5 to emerge inan area bounded by the stator 5 and the rotor 6. The rotor 6 facing the stator5 is arranged on a rotatable axis that can be rotated by means of an electricalmotor. The purpose of the rotor is to grind the lignocellulose-containingmaterial between a surface of the stator and a surface of the rotor. Thus, whenlignocellulose-containing material leaves the feeding channel and enters thebounded area, or refining gap/ disc gap, between the rotor and the stator itflows in on the rotor and due to the rotation of the rotor the lignocellulose-containing material, such as wood chips/ fiber/ pulp, is directed outwards towards the periphery of the rotor and stator. Usually there are provided lO refining segments on the surfaces of the rotor and/ or the stator. The purpose of these refining segments is to achieve a grinding action on the pulp/ fiber.
The lignocellulose-containing material should be fed through the refiner asevenly as possible in order to save energy and promote an even grinding of thepulp/ fiber. Usually the material feed in a refiner typically varies with time t ina more or less periodic fashion as schematically íllustrated in Fig. 2A. Ideallythese feed Variations should be kept at a minimum to save energy and improvefiber quality. It is therefore important to achieve an even feed into the feedscrew, as well as minimal disturbance from back-streaming steam from the defibrator, as Will be described further below.
The defibration difficulty of each individual wood piece fed into a refiner alsotypically varies with time t as schematically íllustrated in Fig. 2B, and theseVariations should also be kept at a minimum. The defibration difficulty perwood piece typically depends on e.g. wood density, wood moisture, chip size, Cooking condition etc.
One problem With common refiner designs is that the chips / fiber / pulp will bedirected towards the periphery of the rotor and stator in an uneven fashion.Large chunks of material will be localized in some positions of the rotor/ statorarrangement while other positions will be more or less devoid of material. Thiswill in turn lead to uneven grinding of the pulp/ fiber. Thus, efforts have to be made to improve the distribution of the material.
Another problem Within the art is that part of the lignocellulose-containing:material initially can get stuck in the middle of the rotor. This might lead tomaterial piling up in the middle of the rotor which can negatively affect thepulp / fiber distribution. A known measure to achieve a more even pulp / fiberdistribution is to provide the rotor surface with a center plate 10, as íllustratedin Fig. 3. The purpose of the center plate is to help feeding the lignocellulose- containing material 7 towards the periphery of the rotor 6 and stator 5. Such a center plate is typically provided With a set of feeding bars or “wings” or Wingprofiles, whose purpose is to direct the chips/ fiber/ pulp more evenly towardsthe rim of the stator/ rotor arrangement. An example of a prior art center plate10 With feeding Wings 100 is schematically illustrated in Fig. 4. The wings areusually elongated protrusions provided on the surface 200 of the center plateof the rotor, where the surface 200 is facing the incoming material ﬂow. Thewings are usually curved e.g. in an arc-shaped form, but straight wings arealso possible. By means of such wings pulp/ fiber will be directed into the openchannels defined between adjacent wings to thereby give a more evendistribution of the pulp / fiber in the refining area. The center plate can havedifferent amount of wings, and the Wings may have different angles on thecenter plate, but the wings are always arranged in such a way that the feedingangle of the wings enable feeding of the lignocellulose-containing materialtowards the periphery of the center plate, dependíng on the direction ofrotation of the rotor and center plate. The feeding angle of a feeding Wing isdefined by the angle between the leading edge of the Wing at a given point anda radial line passing through that point. The leading edge is the edge of thefeeding Wing directed in a same direction as the direction of rotation, and thefeeding angle has a positive value in a direction opposite to the direction ofrotation. Thus, a feeding angle that enables feeding of the material towards the periphery of the center plate is >O° but <90°.
This is illustrated in Fig. 4, Where a rotation of the rotor and center plate 10in the direction of rotation 11 will cause at least part of the lignocellulose-containing material 7 to ﬂow along the feeding wings 100 in a directiontowards the periphery of the center plate 10. Príor art feeding wings commonly go all the way from the center to the periphery of the center plate.
WO2014/ 142732 A1 shows a center plate for a rotor in a pulp refiner. Thecenter plate has a surface provided with a plurality of first wings for directingpulp ﬂowing onto the center of the center plate towards the periphery of the plate, where the surface is a ﬂat surface or a surface with a central lO protuberance and Where each of the first Wings is an arc-shaped protrusionextending between a corresponding first point and a corresponding secondpoint on the surface. The first point is displaced from the center point of theplate and the second point is arranged further from the center point than thefirst point. The first Wings are given an arc-shape that yields a larger pulpfeeding angle than a Circular arc intersecting the center point of the center plate and ending in the same corresponding second point.
However, there is continued need in the art to further improve the pulp / fiberdistribution in a pulp/ fiber refiner. Therefore, there is still a need for a feedingcenter plate Which further improves the pulp/ fiber distribution in the refining area of a pulp/ fiber refiner.
SUMMARY It is an object to provide a feeding center plate Which further improves the pulp /fiber distribution in the refining area of a pulp or fiber refiner.
This and other objects are met by embodiments of the proposed technology.
According to a first aspect, there is provided a center plate for a rotor in a pulpor fiber refiner, where the center plate has a surface provided with at least onefeeding Wing for directing lignocellulose-containing material ﬂowing onto thesurface towards a periphery of the center plate. The at least one feeding Wingis an elongated protrusion extending between a first end and a second end,where the second end is arranged further away from a center of the centerplate than the first end. The second end is displaced relative to the first endin a direction opposite to a direction of rotation of the rotor and center plate.The at least one feeding Wing is provided with at least one opening allowingsteam to flow through the opening or openings in a direction having acomponent directed opposite to the direction of rotation, when the center plate is rotating in the direction of rotation. lO According to a second aspect, there is provided a pulp or fiber refiner With a rotor comprising a center plate as defined above.
Some advantages of the proposed technology are: 0 Back-streaming steam can more easily enter the feed screw and escape,resulting in less feed conﬂicts, which in turn leads to lower energyconsumption, less feed Variations and less build-ups of material in thecenter of the center plate v Less wood chip feed variations are transferred into the working disc gap,which means that a more open disc gap can be used to achieve the samedeﬁbration/reﬁning, which results in lower specific energy (SEC) for thesame fiber quality, more uniform fiber quality, longer overall fiber length and longer refiner segment lifetime.
Other advantages will be appreciated when reading the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS The invention, together with further objects and advantages thereof, may bestbe understood by making reference to the following description taken together with the accompanying drawings, in which: Fig. 1 is a schematic illustration of a part of an embodiment of a typicalpulp / fiber refiner; Fig. 2A is a schematic illustration of typical material feed Variations in arefiner; Fig. 2B is a schematic illustration of typical Variations in defibration difficultyper wood piece fed into a refiner; Fig. 3 is a schematic illustration of an embodiment of a typical defibrator in arefiner; Fig. 4 is a schematic illustration of a center plate for a rotor in a refiner according to prior art; lO Fig. 5 is a schematic illustration of a center plate for a rotor in a refineraccording to an embodíment of the present disclosure; Fig. 6 is a schematic illustration of an example of how lignocellulose-containingmaterial may ﬂow on a center plate according to an embodíment of the presentdisclosure; Fig. 7 is a schematic illustration of an example of how back~streaming steammay ﬂow on a center plate according to an embodíment of the present dísclosure;Fig. 8 is a schematic illustration of an example of how both lignocellulose-containing material and back-streaming steam may ﬂow on a center plateaccording to an embodíment of the present disclosure; Fig. 9 is a schematic illustration of a center plate for a rotor in a refineraccording to an alternative embodíment of the present disclosure; and Figs. IOA-B are schematic illustratíons of a side view of a center plate for a rotorin a refiner according to other alternative embodiments of the present disclosure.
DETAILED DESCRIPTION The present invention generally relates to refíning of lignocellulose-containingmaterial, and more particularly to a center plate for a rotor in a pulp or fiberrefiner, as well as a pulp or fiber refiner with a rotor comprising such a center plate.
Throughout the drawings, the same reference designations are used for similar or corresponding elements.
As described in the background section there is continued need in the art tofurther improve the pulp/ fiber distribution in a pulp/ fiber refiner. Thus, thereis still a need for a feeding center plate Which further improves the pulp/ fiber distribution in the refíning area of a pulp/ fiber refiner.
As described above, Fig. 1 is a schematic illustration of a part of an ernbodiment of a pulp or fiber refiner 1. Lignocellulose-containing material 7, lO SO such as wood chips, is fed into the preheater 2. Steam 8 is input at the bottomof the preheater 2 and goes upwards through the pile of wood chips. The woodchips are discharged from the preheater 2 by a discharge screw 2a and fedinto a feed screw Sa Which feeds the chips via a feeding channel S towards thedefibrator 4 and through a hole in the stator 5 to emerge in the refining gap between the stator 5 and the rotor 6.
When the lignocellulose-containing material enters the refining gap betweenthe rotor and the stator, some of the moisture in the chips/ fiber/ pulp isturned into steam. Some of this steam wants to go backwards against the ﬂowof chips/ fiber/ pulp. Therefore, as illustrated in Fig. 1, the feed screw Sa isusually a ribbon feeder which has a center cavity Sb, surrounding the centeraxis Sc, for allowing steam to ﬂow backwards from the defibrator 4 andthrough the feed screw Sa without interfering with the chip feed. As shown inFig. l the discharge screw 2a usually has a soft chip plug 2b at the típ toprevent steam from entering the discharge screw 2a from the feed screw Sa(and also the opposite). Since wood chips have weight as compared to steam,they end up in the periphery of the ribbon feeder and are fed forwards, whilethe back-streaming steam 8b can ﬂow backwards in the center cavity Sb ofthe ribbon feeder. The return steam 80 can then be evacuated from the ribbonfeeder through a hole. Thus, the ribbon feeder enables efficient feeding without interference from back-streaming steam.
However, in order to escape through the feed screw the steam formed betweenthe rotor and the stator first has to find its Way back towards the center of therotor and stator, working against the flow of lignocellulose-containing materialbeing fed in the opposite direction, as íllustrated in Fig. S. Lignocellulose-containing material 7 is fed through the feed screw Sa into the refining gapand is then directed towards the periphery of the rotor 6 and stator 5. Somesteam 8a is ﬂowing forwards in the same direction as the material 7, but someof the steam 8b is trying to ﬂow backwards against the ﬂow of material 7, thus causing a feed conflict 9. This feed conflict results in unnecessary restriction of the steam ﬂow Which causes higher energy consumption, feed variations ofthe chips/ fiber/ pulp ﬂow which causes lower fiber quality as Well as higherenergy consumption, and build-ups of chips/ fiber/ pulp in the center of thecenter plate. Avoiding the feed conﬂict would result in a more stable chip feed and less build-ups in the center plate.
As described above, and as illustrated in Fig. 3, the rotor 6 may be providedWith a center plate 10 to help feeding the lignocellulose-containing materialtowards the periphery of the rotor 6 and stator 5. However, the prior art centerplates, such as the center plate 10 shown in Fig. 4, all have designs whichWork against the ﬂow of steam trying to escape backwards through the feedscrew. The feeding wings 100 of the center plate 10 of Fig. 4 have a feedingangle designed to feed chips forwards towards the periphery of therotor/ stator, thus causing a feed conflict with the steam trying to ﬂow in the opposite direction.
Also, the chip feeding into the center plate is never constant or even. Theamount of chips fed onto the center plate will vary and that variation is notfavorable to transfer into the working disc gap/ refining gap. A more uniformfeeding of wood chips into the refining gap results in a more uniformdefibration/refining, which in turn may lead to energy savings, improvement in fiber quality and prolonged refiner segment lifetime.
Therefore, the aim of the present invention is to provide a center plate whichfacilitates evacuation of back-streaming steam and at the same time enables equalization of incoming feed Variations.
A center plate for a rotor in a pulp or fiber refiner according to an embodimentof the invention is illustrated in Fig. 5. The center plate 10 has a surface 200provided with at least one feeding wing 100 for directing lignocellulose-containing material flowing onto the surface 200 towards a periphery of the center plate 10. The at least one feeding wing 100 is an elongated protrusion extending between a first end l00a and a second end 100b, where the secondend 100b is arranged further away from a center of the center plate 10 thanthe first end l00a. The second end 100b is displaced relative to the first endl00a in a direction opposite to a direction of rotation 11 of the rotor and centerplate 10. The feeding Wing or wings 100 of the center plate 10 in Fig. 5 isprovided With at least one opening/ hole/ gap 101 which allows steam to ﬂowthrough the opening or openings 101 in a direction Which has a componentdirected opposite to the direction of rotation 1 1, When the center plate 10 is rotating in the direction of rotation 11.
The displacement of the second end 100b relative to the first end l00a in adirection opposite to the direction of rotation 11 results in a feeding angle ofthe feeding Wing or wings 100 that enables feeding of the lignocellulose-containing material towards the periphery of the center plate 10, when thecenter plate 10 is rotating in the direction of rotation 11. As described above,a feeding angle that enables feeding of the material towards the periphery ofthe center plate is >0° but <90°.
Depending e.g. on the size and number of openings, among other things, someof the lignocellulose-containing material may also ﬂow through the opening oropenings. Thus, in a particular embodiment the feeding Wing or Wings 100 isprovided with at least one opening 101 Which allows lignocellulose-containingmaterial to flow through the opening or openings 101 in a direction which hasa component directed opposite to the direction of rotation 1 1, when the center plate 10 is rotating in the direction of rotation 11. ln some embodiments the at least one feeding Wing 100 is provided with aplurality of openings 101. In other embodiments the center plate 10 comprisesmultiple feeding wings 100, each of which comprises one or more openings 101, as illustrated in Fig. 5.
In some embodiments, one or more openings/gaps/ holes 101 in the feedingwings 100 may go all the way down to the surface 200 of the center plate 10, sothat the feeding wing or Wings 100 are completely cut off into separate píeces,as shown e.g. in Fig. 10A. In other embodiments, one or more openings 101 donot go all the way down to the surface 200, but instead the opening or openings101 are cut out from the feeding wing or Wings 100 so that a part or parts of thefeeding wing or wings 100 are left at the bottom of the opening or openings 101, as shown in Fig. 10B.
Fig. 6 illustrates an example of how the lignocellulose-containing material 7 mayﬂow on the center plate 10 according to the embodiment of Fig. 5. The material7 ﬂows on the surface 200 and some of the material 7 may be directed to ﬂowalong the feecling wings 100 in a main direction towards the periphery of thecenter plate 10, when the center plate 10 is rotating in the direction of rotation11. The material 7 may of course also ﬂow in other directions, but since thelignocellulose-containing material should eventually end up in the reﬁning gapin order to be reﬁned, this is the preferred direction of ﬂow of the material 7.Depending on e.g. the size and number of the openings, some of the materialmay 7 enter through the openings 101 and ﬂow towards an adjacent feedingwing 100 in a main direction opposite to the direction of rotation 11 in someembodiments. The openings 101 in the wings 100 may create turbulence whenthe material 7 ﬂows through them, which will cause buffering/equalization ofthe material ﬂow resulting in less variation in material feed. The openings willin such embodiments also cause a more even distribution of material over thecenter plate, since the material can ﬂow through the openings to a next wing.Less material feed Variations will result in a more stable disc gap, whereas abetter distribution of material will result in a more stable as well as a more opendisc gap. This will in turn result in less energy consumption, more uniform fiber quality and longer segment lifetime.
Fig. 7 illustrates an example of how back-streaming steam 8b can ﬂow on the center plate 10 according to the embodiment of Fig. 5. The back-streaming 11 steam 8b wants to ﬂow in a main direction towards the center of the center plate10 in order to escape through the feed screw. The steam 8b ﬂows on the surface200 and is allowed to ﬂow through the openings 101 in the feeding wings 100in a main direction opposite to the direction of rotation 11. Thus, the openingscreate a passage for back-streaming steam 8b, which makes it easier for thesteam 8b to find its way to the center of the center plate 10, and hence there willbe less restriction for the back-streaming steam and less feeding conﬂicts withthe material ﬂow feed, which results in less Variations in material feed. Asmentioned above, less material feed Variations will result in a more stable discgap, which in turn results in less energy consumption, more uniform fiber quality and longer segment lifetime.
Fig. 8 illustrates an example of both the ﬂow of lignocellulose-containingmaterial 7 and the ﬂow of back-streaming steam 8b on the center plate 10 according the embodiment of Fig. 5.
According to a particular embodiment, such as illustrated in Figs. 5-8, at leastone opening 101 in a feeding Wing 100 is arranged such that at least a sidewall 101' of the opening 101 is directed obliquely towards the center of thecenter plate 10, i.e. the side wall 101' is directed in a direction having acomponent directed towards the center of the center plate 10 and a componentdirected opposite to the direction of rotation 11 of the center plate 10. Theinclination of the side wall 101' is intended for guiding the steam Sb to flowthrough the opening 101 obliquely towards the center of the center plate 10,when the center plate 10 is rotating in the direction of rotation 11, asillustrated in Fig. 7. The angle of the side wall 101' may be varied between O°and 90° in different embodiments, where 0° in this case is a direction oppositeto the direction of rotation 1 1, and 90° is a radial direction towards the center of the center plate 10.
By varying the angle of the side wall 101', the direction of the steam ﬂow can be varied in different embodiments. Also, the angle of the side wall 101' affects 12 how easy it Will be for the lignocellulose-containing material 7 to flow throughthe opening 101. The more the side Wall 101' is directed towards the center ofthe center plate 10, the more difficult it will be for the material 7 to ﬂowthrough the opening 101 When the center plate is rotating, due to the Weight of the material.
Thus, the amount of lignocellulose-containing material 7 ﬂowing through theopening or openings 101 depends, among other things, on the size, numberand angle of the opening or openings 101, and also on the size, number and angle of the feeding Wing or wings 100.
In a particular embodiment, the surface 200 of the center plate 10 is providedWith at least two feeding Wings 100. A side Wall 101' of an opening 101 in afirst feeding Wing 100 is inclined as described above, and is directed towardsan opening 101, also with an inclined side wall 101', in the next feeding Wing100, for guiding the steam 8b to ﬂoW through the openings 101 obliquelytowards the center of the center plate 10, When the center plate 10 is rotatingin the direction of rotation 11. This is illustrated in Fig. 7. Since the side walls101' of the openings 101 are inclined as described above, the arrangement ofthe openings 101 in this embodiment creates an “intended path” which isdirected obliquely towards the center of the center plate, and along which thesteam 8b may ﬂow. The term “intended path” indícates that this is a preferredpath that would be preferable for the steam to follow, but of course the steammay also ﬂoW in other directions. However, the intention of the arrangementof the openings 101 is to make it possible for the back-streaming steam tofollow this path in order to facilitate for the steam to reach the center of thecenter plate and escape through the feed screw. Since the angle of the sideWalls 101' may be varied between 0° and 90°, where 0° in this case is adirection opposite to the direction of rotation 1 1, and 90° is a radial directiontowards the center of the center plate 10, the angle of the intended path onthe center plate 10 may also be varied between 0° and 90° in different embodiments. 13 In particular embodiments the center plate 10 comprises a plurality of feedingwings 100, each of which comprises at least one opening 101 with at least a sidewall 101' being inclined as described above. The openings 101 in the feedingwings 100 are arranged such that at least one intended path as describedabove is created by the openings 101, for guiding the steam to ﬂow throughthe openings 101 along the intended path or paths and obliquely towards thecenter of the center plate 10, when the center plate 10 is rotating in thedirection of rotation 11, as illustrated in Fig. 7. The number of intended pathsand their angles on the center plate may differ in different embodiments.Again, the purpose of the “intended paths” is to facilitate for the back-streamingsteam to reach the center of the center plate and escape through the feed screw.Hence there will be less restriction for the back-streaming steam and less feeding conﬂicts with the material ﬂow feed, as mentioned above.
The curving/bending/arching in a direction opposite to the direction of rotation feeding wing or wings of the center plate 10 may be11 in an embodiment. The exact shape of the Curved feeding wing or wings maydiffer in different embodiments, as an example the feeding wing or wings maybe are-Shaped in a particular embodiment. The angle of curvature may also varyalong the wing in other embodiments. Curved feeding wings are quite commonin the art and have proven to provide efﬁcient material distribution on the centerplate, but other shapes of the feeding wings may also be possible in alternativeembodiments. As an example, straight feeding wings may be easy tomanufacture and Fig. 9 shows an example embodiment of a center plate 10 withstraight feeding wings 100. Also, the number of wings and their angles on thecenter plate may differ in different embodiments, but the wings should alwayshave a feeding angle that enables feeding of the lignocellulose-containingmaterial towards the periphery of the center plate when the rotor and centerplate are rotating in the direction of rotation, i.e. the feeding angle of the feeding wings should be >0° and <90°. 14 In a particular embodiment, the second end 100b of the feeding Wing or Wings100, i.e. the outer end or the end being closest to the periphery of the centerplate 10, is arranged at the periphery of the center plate 10.
In a particular embodiment, the first end 100a of the feeding Wing or wings100, i.e. the inner end or the end being closest to the center of the center plate10, is displaced from the center of the center plate 10, i.e. the feeding wing orwings do not go all the way to the center of the center plate 10. For e. g. straightfeeding wings this is a necessary condition in order to achieve a feeding angle of >0°.
In order to facilitate for the back-streaming steam to escape through a hollowfeed screw or ribbon feeder feeding lignocellulose-containing material onto thecenter plate, it may be advantageous if there is a space between the inner endsof the feeding wings and the center axis of the feed screw, the space allowingsteam to flow from the surface of center plate, along the center aXis of the feedscrew, and escape through the feed screw. Therefore, in an embodiment thefirst end 100a of the feeding wing or wings 100 is displaced from the center ofthe center plate 10, at a distance which is larger than the radius of the end ofthe center aXis 3c of the hollow feed screw 3a, see Figs. 1 and 3, where the end is located adjacent to the surface 200 of the center plate 10.
In some embodiments, the surface 200 of the center plate 10 is provided witha rotationally symmetric protuberance or bulge/bump with its centercoinciding with the center of the center plate. This is illustrated in a side viewof an embodiment of a center plate 10 in Figs. 10A-B. The center plate 10 inFigs. 10A~B has a surface 200 provided with a feeding wing 100 comprisingseveral openings 101 and a central protuberance 102, shaped as a knob orrounded hill in this embodiment. For simplicity, only one feeding wing 100 isshown in the embodiments of Figs. 10A-B, but of course the center plate 10could comprise two or more feeding wings 100. The height and width of the protuberance and e.g. the shape and inclination of its lateral/ side wall/ surface may vary in different embodiments. Other shapes of theprotuberance are also possible in other embodiments, such as e.g. a Sphere,a cylinder, a cone or a frustum of a cone, but preferably the protuberance 102is a, smooth protuberance without sharp edges, to avoid possible irregularities in the ﬂow which could lead to a turbulent motion of the chips/ fiber/ pulp.
The main purpose of a central protuberance is to avoid lignocellulose-containing material from building up at the center of the center plate. Thematerial falling into the central area of the center plate will be pushed awayby the protuberance towards the feeding wings. Furthermore, theprotuberance has the purpose of strengthening the central area of the centerplate. Since the lignocellulose-containing material will mainly fall into thecentral area of the center plate and change direction there, i.e. change froman axial motion along the feeding axís to a radial motion along the surface ofthe center plate, significant forces will be applied on the sides of the feedingwings from the lignocellulose-containing material. By providing the centerplate with a central protuberance a more robust center plate is obtained since the height of the feeding wings above the protuberance is smaller than the height of the wings above an essentially ﬂat surface.
To ensure that the central protuberance 102 does not constitute an obstaclefor the back-streaming steam 8b trying to escape through the feed screw, itmay be advantageous if there is a space between the inner ends, i.e. the endsclosest to the center of the center plate 10, of the feeding wings 100 and thelateral wall/ surface of the protuberance 102, the space allowing steam to flowfrom the surface of the center plate, along the center axis of the feed screw,and escape through the feed screw. Therefore, in an embodiment the first endlO0a of the feeding wing or wings 100 is displaced from the center of the center plate 10, at a distance Which is larger than a radius of the protuberance 102.
If the protuberance is cylindrical in shape, the radius is of course constant over the height of the protuberance, but if the protuberance is shaped as a 16 rounded hill as in Figs 10A-B, or e.g. as a cone or a frustum of a cone, or evena sphere, the radius varies With the heíght of the protuberance. Thus,depending on Which radius is used as a reference for the displacement of thefirst end 100a of the feeding Wing or Wings 100, the first end 100a may in thecase of a protuberance shaped as e.g. a rounded hill, cone or frustum belocated somewhere on the inclining Wall of the protuberance, i.e. the feedingWing or Wings 100 and the protuberance 102 may overlap in someembodiments. Depending on the displacement of the first end l0Oa, the sizeof the space for allowing steam to escape Will vary, i.e. a larger displacementof the first end 100a relative to the center of the center plate 10 Will result ina larger space for the steam to escape. In a particular embodiment, the firstend 100a of the feeding Wing or Wings 100 is displaced from the center of thecenter plate 10 at a distance Which is larger than a largest radius r of theprotuberance 102. This is illustrated in Figs. 10A-B, Where the radius r in thisparticular case is measured at the surface 200 of the center plate 10, sincethis protuberance is Widest/ has the largest radius at the surface 200 of the center plate 10.
As described above, the surface of the center plate can be provided With oneor more feeding Wings. In some embodiments, the surface 200 of the centerplate 10 is provided With a plurality of feeding Wings 100. In a particularembodiment the first ends l0Oa of the feeding Wings 100 are symmetricallydistributed With respect to the center of the center plate 10. In anotherparticular embodiment the second ends 100b of the feeding Wings 100 are symmetrically distributed With respect to the center of the center plate 10.
By having Wings feeding “intermittently” due to the openings/ gaps/holes in thefeeding Wings according to the present invention, at least the following advantages can be achieved: v The steam can more easily enter the feed screW and escape, resulting in less feed conﬂicts, Which in turn leads to lower energy consumption, less 17 feed variations and less build-ups of material in the center of the centerplate I Less wood chip feed variations are transferred into the working disc gap,which means that a more open disc gap can be used to achieve the samedeﬁbration/reﬁning, which results in lower specific energy (SEC) for thesame fiber quality, more uniform fiber quality, longer overall fiber length and longer reﬁner segment lifetime.
In summary, the openings/gaps/holes in the feeding wings of the center plateaccording to the present invention enable improved equalization of feed variations as well as facílitated steam evacuation in a pulp or fiber reﬁner.
All embodiments of a center plate 10 according to the present disclosure can befitted to a rotor arrangement of well-known pulp/ fiber refiners. One example ofsuch a pulp/ fiber reﬁner 1 is schematically described above with reference toFig. 1. Other refiners are however also possible to use in connection With a centerplate 10 according to the present disclosure. Such refiners include refiners withtwo rotors instead of a rotor~stator arrangement, e.g. two rotors that can be rotated independently.
The embodiments described above are merely given as examples, and it shouldbe understood that the proposed technology is not limited thereto. It will beunderstood by those skilled in the art that various modifications,combinations and changes may be made to the embodiments withoutdeparting from the present scope as defined by the appended claims. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible.

权利要求:
Claims (17)
[1] 1. Center plate (10) for a rotor (6) in a pulp or fiber refiner (1), said centerplate (10) having a surface (200) provided with at least one feeding Wing (100)for directing lignocellulose-containing material (7) ﬂowing onto said surface(200) towards a periphery of the center plate (10), where said at least one feeding Wing (100) is an elongated protrusion extendingbetween a first end (l00a) and a second end (l00b), said second end (l00b)being arranged further away from a center of the center plate (10) than saidfirst end ( 100a), and said second end (l00b) being displaced relative to saidfirst end (l00a), in a direction opposite to a direction of rotation (11) of therotor (6) and center plate (10), characterized in that said at least one feeding wing (100) is provided with at least one opening(101) allowing steam (8b) to ﬂow through said at least one opening (101) in adirection having a component directed opposite to the direction of rotation (11), when the center plate (10) is rotating in the direction of rotation (1 1).
[2] 2. Center plate (10) according to claim 1, characterized in that said atleast one feeding wing (100) is provided with at least one opening (101)allowing lignocellulose-containing material (7) to ﬂow through said at least oneopening (101) in a direction having a component directed opposite to thedirection of rotation (1 1), when the center plate (10) is rotating in the direction of rotation (11).
[3] 3. Center plate (10) according to claim 1 or 2, characterized in that saidat least one opening (101) is arranged such that at least a side wall (101') ofsaid opening (101) is directed in a direction having a component directedtowards the center of the center plate (10) and a component directed oppositeto the direction of rotation (11) of the center plate (10), for guiding steam (Sb)to ﬂow through the opening (101) obliquely towards the center of the centerplate (10), when the center plate (10) is rotating in the direction of rotation(1 1). 19
[4] 4. Center plate (10) according to claim 3, characterized in that saidsurface (200) is provided With at least two feeding Wings (100) and a side wall(101) of an opening (101) in a first feeding Wing (100) is directed towards anopening (101) in a next feeding Wing (100), for guiding steam (8b) to ﬂowthrough said openings (101) obliquely towards the center of the center plate (10), When the center plate (10) is rotating in the direction of rotation (11).
[5] 5. Center plate (10) according to any of the clairns 1-4, characterized inthat said at least one feeding Wing (100) is curving in a direction opposite to the direction of rotation (11).
[6] 6. Center plate (10) according to any of the clairns 1-4, characterized in that said at least one feeding Wing (100) is straight.
[7] 7. Center plate (10) according to any of the clairns l-6, characterized inthat said second end (100b) of said at least one feeding Wing (100) is arranged at the periphery of the center plate (10).
[8] 8. Center plate (10) according to any of the claims 1-7, Wherein said firstend (l00a) of said at least one feeding Wing (100) is displaced from the center of the center plate (10).
[9] 9. Center plate (10) according to claim 8, characterized in that said firstend (l00a) of said at least one feeding Wing (100) is displaced from the centerof the center plate (10) at a distance being larger than a radius of an end of acenter axis (80) of a hollow feed screw (3a), said end being located adjacent to said surface (200) of said center plate (10).
[10] 10. Center plate (10) according to clairn 8 or 9, characterized in that saidsurface (200) is provided With a rotationally syrnrnetric protuberance (102) with its center coinciding with the center of the center plate (10).
[11] 11. Center plate (10) according to claim 10, characterized in that said firsterld. (lOOa) of said at least one feeding Wing (100) is displaced from the centerof the center plate (10) at a distance being larger than a radius of said protuberance (102).
[12] 12. Center plate (10) according to claim 11, characterized in that said firstend (lOOa) of said at least one feeding Wing (100) is displaced from the centerof the center plate (10) at a distance being larger than a largest radius (r) of said protuberance (102).
[13] 13. Center plate (10) according to any of the claims 1-12, characterized inthat said at least one feeding Wing (100) is provided With a plurality ofopenings (101).
[14] 14. Center plate (10) according to any of the claims 1-13, characterized in that said surface (200) is provided With a plurality of feeding Wings (100).
[15] 15. Center plate (10) according to claim 14, characterized in that the firstends (100a) of the plurality of feeding Wings (100) are syrnmetricallydistributed With respect to the center of the center plate (10).
[16] 16. Center plate (10) according to claim 14 or 15, characterized in that thesecond ends (100b) of the plurality of feeding Wings (100) are syrnmetricallydistributed With respect to the center of the center plate (10).
[17] 17. Pulp or fiber refiner (1) With a rotor (6) comprising a center plate (10) according to any of the claims 1-16.

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同族专利:

公开号 | 公开日

CN108026693A|2018-05-11|

WO2017061936A1|2017-04-13|

US20180229242A1|2018-08-16|

US10449545B2|2019-10-22|

SE539119C2|2017-04-11|

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引用文献:

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US4191338A|1977-06-03|1980-03-04|The Bauer Bros. Co.|Infeed disc for disc-type refiners|

FI73256C|1984-10-19|1987-09-10|Yhtyneet Paperitehtaat Oy|Target segments.|

NO162525C|1986-03-18|1990-01-10|Thune Eureka As|DISC OFFICER DEVICE.|

SE508502C2|1997-02-25|1998-10-12|Sunds Defibrator Ind Ab|Feed element for grinding apparatus with two opposite grinding means, one of which is stationary and one rotating|

DE202006002999U1|2006-02-24|2007-06-28|Voith Paper Patent Gmbh|Disc refiner for grinding suspended fibrous materials comprises a rotor and stators, each having grinding tools that cooperate to form a conical grinding zone|

US8028945B2|2007-05-31|2011-10-04|Andritz Inc.|Refiner plates having steam channels and method for extracting backflow steam from a disk refiner|

SE537031C2|2013-03-12|2014-12-09|Valmet Oy|Center plate in mass refiner with arch-shaped bars|

SE539121C2|2015-10-08|2017-04-11|Valmet Oy|Feeding center plate in a pulp or fiber refiner|SE541111C2|2017-06-19|2019-04-09|Valmet Oy|Steam evacuation in a pulp or fiber refiner|

CA3090180A1|2018-02-26|2019-08-29|Andritz Inc.|Cleaning notches and passages for a feeding or refining element|

SE542986C2|2019-03-13|2020-09-22|Valmet Oy|Double disc pulp refiner comprising a center plate|

SE543499C2|2020-02-12|2021-03-09|Valmet Oy|Center ring provided with wings|

法律状态:

优先权:

申请号 | 申请日 | 专利标题

SE1551300A|SE539119C2|2015-10-08|2015-10-08|Feeding center plate in a pulp or fiber refiner|SE1551300A| SE539119C2|2015-10-08|2015-10-08|Feeding center plate in a pulp or fiber refiner|

PCT/SE2016/050952| WO2017061936A1|2015-10-08|2016-10-05|Feeding center plate in a pulp or fiber refiner|

CN201680052135.XA| CN108026693B|2015-10-08|2016-10-05|Feeding spider in paper pulp or fiber refining machine|

US15/752,063| US10449545B2|2015-10-08|2016-10-05|Feeding center plate in a pulp or fiber refiner|

EP16853992.2A| EP3359728B1|2015-10-08|2016-10-05|Feeding center plate in a pulp or fiber refiner|

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