EP4644605A1

EP4644605A1 - Pulper rotor

Info

Publication number: EP4644605A1
Application number: EP25165820.9A
Authority: EP
Inventors: Jonne NÄKKI; Pekka Pekkonen; Joni PIIPONNIEMI; Illya SARVI
Original assignee: Valmet Technologies Oy
Current assignee: Valmet Technologies Oy
Priority date: 2024-04-29
Filing date: 2025-03-25
Publication date: 2025-11-05
Anticipated expiration: 2045-03-25
Also published as: FI131934B1; FI20245532A1; CN120867125A; EP4644605B1

Abstract

The invention relates to a pulper rotor (10) comprising a pulper rotor body (15), which has a center hub (12) and from the outer circumference of the center hub (12) extending a plurality of wings (14). The pulper rotor (10) further comprises a plurality of insert vanes (20), each of the insert vanes (20) is removably attached to the pulper rotor body (15) at the respective wings (14) thereof and the insert vanes (20) are attached to the pulper rotor body (15) by a formfitting attachment.

Description

Technical field

The present invention relates to pulper rotors for pulpers used in connection with pulp handling for fiber web production. More especially the invention relates to a pulper rotor according to the preamble part of claim 1.

Background

As known from the prior art in fiber web machines, especially in paper and board machines, the fiber web is produced and treated in an assembly formed by a number of apparatuses arranged consecutively in a process line. A typical production and treatment line comprises a forming section comprising a head box and a forming unit and a press section as well as a subsequent drying section and a reel-up. The production and treatment line can further comprise other devices and sections for finishing the fiber web, for example, a size press, a calender, a coating section. The production and treatment line also comprises typically at least one winder for forming customer rolls as well as a roll packaging apparatus.
Before the head box fiber suspensions comprising recycled and/or virgin fibers are treated in a treatment system to be fed into the head box to be used to produce the fiber webs. A treatment system of the fiber suspensions for example comprises a pulping section, a deashing system, a detrashing system, a coarse filtering section, a centrifugal cleaning section, a fractionation section, a fine filtering system, a fiber thickening system and fiber refining systems.
In pulping sections connected to the fiber web production lines using recycled material, in pulpers bales of recycled material are broken and defibered to fiber pulp; in vertical or horizontal pulpers for repulping of baled pulps. A vertical pulper is typically used, when homogeneous slushing results with low energy consumption are needed, while a horizontal pulper, with its low height requirement, is typically used for rebuilds where limited space is available. The pulpers comprise a rotating pulper rotor with vanes to break and to defiber the baled pulp. In the pulper, i.e. in a vat, by the pulper rotor with the vanes the pulp bales are broken and the pulp broke is defibered into fiber suspension comprising typically about 95% water and 5% fiber is caused to a rotating flow by a rotor. The pulper rotor has a generally cylindrical form and in pulper rotors orientation of the center axis of the cylindrical form of the vat is substantially vertical. In the vertical pulpers the pulper rotor with the vanes located at the bottom of the pulper, typically in a for example conical or dish end extension of the cylindrical form, causes a rotating flow inside the pulper. During the rotating flow caused by the pulper rotor by the vanes the bales are broken and the fiber suspension is defibered.
In the pulper the operating conditions are extreme and often lifetime of wearing components such as the pulper rotor vanes is only 3 to 4 months.
The bales of recycled materials to be treated in the pulper typically also comprises additional harmful non-fiber matter, for example hard material particles, sand, metal, glass etc. which undesirably have been added into the recycled fiber material during collection of the recycle material. These foul particles cause the vanes of the pulper rotor to wear causing dimensions and edge profiles of the vanes to changes, which causes lost efficiency of the pulper. Further, as the vertical functional height of the pulper decreases, pumping forces in the pulper and power of the pulper decrease. Finally, the pulper is no longer operational and the pulper rotor vanes need to be repaired by repair by hard facing, in which welding due to the wear lost areas are filled by welding material. This is time-consuming and requires that the pulper rotor is disassembled from the pulper and taken into a repair location, as the pulper rotor with the vanes is made of a single cast piece. This is also cumbersome, as the pulper rotors are heavy machine parts, diameter of them is typically about 2 meters. Further, for each pulper typically at least two pulper rotors have been provided, one for operation during repair of the other.
For a pulper often also vanes with different profiles are needed for optimizing production and/or energy consumption. This requires in the arrangements according to prior art that the whole pulper rotor is changed, which cumbersome as mentioned above, the pulper rotors are heavy machine parts, which are not easy to handle.
In utility model publication AT16295U1 is disclosed a pulper rotor including a hub, a plurality of blades and a plurality of pumping fins, the plurality of blades and a plurality of pumping fins surround the hub, the plurality of blades and a plurality of pumping fins, in which the blade roots of the blades are fixed to the hub, and the blades and pumping fins are formed from plates and then fixedly connected to the hub; the bottom surface of each pumping fin is connected to each of the hubs. In this known arrangement at least part of the end side and bottom side of the pumping fin is fixed on the outer circumference of the hub through fixed connection means such as welding and the bottom side of the pumping fin is also fixedly connected to the blade on the bottom side. The pumping fins and blades of the rotor using plates are separately prefabricated and then connected to the hub. When foul particles have caused the fins and blades of the pulper rotor to wear, the fins need to be repaired and changed, which is time-consuming as it requires that the attachment welds are removed, which can take even one workday, and then the fins taken to be repaired. Also, if different profiles for the fins are needed, the welds need to be removed and new fins and blades attached by welding.
An object of the invention is to create a pulper rotor, in which the disadvantages and problems of prior art pulper rotor designs relating to wear of the vanes of the pulper rotor are eliminated or at least minimized.
An object of the invention is to create a pulper rotor, in which the disadvantages and problems of prior art pulper rotor designs relating to changeability of profiles of the vanes of the pulper rotor are eliminated or at least minimized.

Summary

In order to achieve the above objects and those that will come apparent later the pulper rotor according to the invention is mainly characterized by the features of the characterizing part of the independent claim 1. Advantageous aspects and features of the invention are presented in the dependent claims.
According to the invention the pulper rotor comprises a pulper rotor body, which has a center hub and from the outer circumference of the center hub extending a plurality of wings, wherein the pulper rotor further comprises a plurality of insert vanes, each of the insert vanes is removably attached to the pulper rotor body at the respective wings thereof and the insert vanes are attached to the pulper rotor body by a formfitting attachment.
According to an advantageous feature of the invention each insert vane has a blade and a support element and the blade extends upwards from the support element. Advantageously, each insert vane has a blade and a support element, which blade is vertical and the support element is horizontal and the blade extends upwards from the support element in use position of the pulper. The support element can extend in rotation direction of the pulper rotor frontwards in respect of the blade. The support element is often also called as a vokes vane and the blade is often called as a ps vane.
According to an advantageous feature of the invention each insert vane comprises at least one flange attached on the pulper rotor body by a screw attachment.
According to an advantageous feature of the invention insert vane comprises two flanges formed in the support element: a hub flange and a wing flange and the hub flange is attached on the center hub of the pulper rotor body by a screw attachment and the wing flange s attached on the wing of the pulper rotor body by a screw attachment.
According to the invention for the formfitting attachment the pulper rotor body comprises for each insert vane at least one key and at least one groove, and each of the insert vanes comprise correspondingly at least one key slot and at least one protrusion, and the keys and the grooves of the pulper rotor body are formfitting with the key slots and the protrusions of the insert vanes.
According to an advantageous feature of the invention the keys and the grooves of the pulper rotor body located at wings of the pulper rotor body.
According to an advantageous feature of the invention the keys are located at outer tip ends of the wings.
According to an advantageous feature of the invention the keys extend over less than half of the length of the wings.
According to an advantageous feature of the invention the insert vanes are made by casting.
According to an advantageous feature of the invention the insert vanes are of wear-resistant material, advantageously of martensitic or duplex stainless-steel.
According to an advantageous feature of the invention for the screw attachment, the flange has screw openings and the pulper rotor body has corresponding screw openings, through which openings screws or bolts are fastened.
According to an advantageous feature of the invention for the screw attachment, the hub flange has screw openings and the pulper rotor body has at the center hub corresponding screw openings, through which openings of the center hub and of the hub flange screws or bolts are fastened, and the wing flange has screw openings and the pulper rotor body has at the wings corresponding screw openings, through which openings of the wings and of the wing flange screws or bolts are fastened.
According to an advantageous feature of the invention the screw openings of the flange/-s have an upwards opening wider cavity for heads of the screws or bolts.
According to an advantageous feature of the invention caps are provided for closing the cavities when the screws or bolts are in place.
According to an advantageous aspect the pulper rotor vanes are made of separate insert vanes to be fastened to the pulper rotor body. Thus, for repair only the insert vanes need to be removed from the pulper. These inserts are easy to manage and only the inserts need to be replaced after wear to have the pulper again in operational condition. Thus, significant time savings are achieved. Additionally, the inserts can be made of more wear-resistant material than the pulper rotor body and thus, cost-savings in material costs are achieved. The functional dimensioning of the insert vanes can be varied to provided different operational parameters merely by replacing the insert vanes with ones with different functional parameters. For example, the height of the vanes has an effect to the energy consumption of the pulper and thus, by optimizing the height of the vanes optimal operating conditions and energy consumption can be achieved.
According to an advantageous aspect of the invention the fastening of the insert vanes to the pulper rotor body comprises a screw mounting and a formfitting fastening between the insert vanes and the respective part of the pulper rotor body, which secures the fastening as well as the correct location of the insert vanes on the pulper rotor body. Furthermore, the formfitting fastening receives any tensional forces and thus, the screw mounting is not affected by tension loads.

Brief description of the drawings

Aspects of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of some example embodiments when read in connection with the accompanying drawings and in the following the invention is described in more detail referring to the accompanying drawing, in which

In figures 1A-1B is shown an advantageous example of a pulper rotor according to the invention,
In figures 2A-2B is schematically shown an advantageous example of a formfitting attachment configuration in a pulper rotor body of the pulper rotor example according to figures 1A-1B,
In figures 3A-3D is schematically shown an advantageous example of an insert wing of the pulper rotor according to figures 1A-1B.

Detailed description

During the course of this description like numbers and signs will be used to identify like elements according to the different views which illustrate the invention. Repetition of some reference signs may have been omitted in the figures for clarity reasons.
With reference to figures 1A-3D the pulper rotor 10 has a pulper rotor body 15, which has a center hub 12 from the outer circumference of the center hub 12 extending a plurality of wings 14. The center hub 12 may also comprise a center opening 11. The center hub 12 is provided for attaching the pulper rotor body 15 to a drive for rotating the rotor. Typically, the attachment is a screw attachment with from above attached screws to the screw openings 120. The rotor body 15 with its wings 14 is formed as one unity, for example of a thick plate material. Depending on the size of the pulper rotor 10 the center hub 12 is elevated or not from the upper surface level of the other parts of the pulper rotor body 15. For pulper rotors 10 of bigger sizes the center hub 12 is typically elevated, as shown in the example of figures and for pulper rotors 10 of smaller sizes the center hub 12 is not elevated, i.e. the upper surface of the pulper rotor body 15 is level. The pulper rotor 10 further comprises a plurality of insert vanes 20. Each of the insert vanes 20 is removably attached to the pulper rotor body 15 at the respective wings 14 thereof. Rotating direction of the pulper rotor 10 is indicated by an arrow S, i.e. in the example the direction of the rotation is counterclockwise.
Each insert vane 20 has an upwards extending blade 22 on a support element 21. Thus, each insert vane 20 has a blade 22 and a support element 21. The blade 22 is vertical and the support element 21 is horizontal and the blade 22 extends upwards from the support element 21 in use position of the pulper. The support element 21 can extend in rotation direction of the pulper rotor 10 frontwards in respect of the blade 22. Each insert vane 20 comprise at least one flange 12; 23 formed on the support element 21. In the example of the figures there are two flanges 23; 24 formed in the support element 21: a hub flange 23 for attachment to the elevated center hub 12 and a wing flange 24 for attachment to the outer circumferential part of the pulper rotor body 15. The hub flange 23 is attached on the center hub 12 of the pulper rotor body 15 by a screw attachment, the hub flange 23 has screw openings 26 and the pulper rotor body 15 has at the center hub 12 corresponding screw openings 16, through which openings 16, 26 of the center hub 12 and of the hub flange 23 screws or bolts are fastened. Correspondingly, the flange 24 is attached on the corresponding wing 14 of the pulper rotor body 15 by a screw attachment, the wing flange 24 has screw openings 26 and the pulper rotor body 15 has at the corresponding wing 14 corresponding screw openings 17, through which openings 17, 27 of the wings 12 and of the wing flange 24 screws or bolts are fastened. Advantageously, the openings 26, 27 of the flanges 23, 24 have an upwards opening wider cavity 26A, 27A for heads of the screws or bolts. Advantageously, caps for closing the cavities, when the screws or bolts are in place may be provided to prevent wear of the screw of bolt heads and fouling of the screw attachments. The caps may be attached by small attachment spot welds, which are easily removed by cutting. The screws or bolts are advantageously made of stainless steel. In case the pulper rotor body 15 is level only one flange is needed and the flange is correspondingly attached by a screw attachment to the pulper rotor body 15.
The plurality of wings 14 and the plurality of insert vanes 20 are located spaced apart extending at the outer circumferential edge of the pulper rotor body 15. The insert vanes 20 extend at least over half the length of the wing 14, advantageously substantially over the length of the wing 14.
Between the pulper rotor body 15 at the wings 14 and the insert vanes 20 also a formfitting attachment is provided, as show also more detailed in figures 2A-2B. For the formfitting attachment, in the example of the figures, the pulper rotor body 15 comprises at each wing 14 a key 19 and a groove 18. The keys 19 are located at outer tip ends of the wings 14 and the keys 19 extend over less than half of the length of the wings 14. The insert vanes 20 comprise correspondingly a key slot 28 and a protrusion 29, as can be seen from fig. 3B. The key 19 and the groove 18 at the wing 14 are formfitting with the key slot 28 and the protrusion 29. The formfitting attachment between the pulper rotor body 15 and the insert vanes 20 may also comprise in the pulper rotor body 15 more than one keys 19 and/or more grooves 18, and respectively the insert vanes 20 comprises more key slots 28 and protrusions 29. The formfitting attachment also receives the forces exerted and thus, the screw attachment is prevented from these. The formfitting attachment the support between the pulper rotor body 15 and the insert vanes 20 provides supporting corresponding to that achieved by welding.
Thus, a secure and supporting, but openable attachment between the insert vanes 20 and the pulper rotor body 15 is achieved and replacement of the insert vanes 20 is facilitated. The formfitting attachment also receives the forces exerted and thus, the screw attachment is prevented from these.
The insert vanes 20 are advantageously made by casting, or by welding from wrought plate material, and finalizing the forms as required by chip removing machining. The insert vanes 20 are advantageously of wear-resistant material, for example of martensitic or duplex stainless-steel material. Advantageously other parts of the pulper rotor 10 are made of steel grade like1.4162, 1.4462, 1.4313, 1.4418 or 1.4542 according to the standard EN 10088-1.
In the description in the foregoing, although some functions have been described with reference to certain features, those functions may be performable by other features whether described or not. Although features have been described with reference to certain embodiments or examples, those features may also be present in other embodiments or examples whether described or not. Above the invention has been described by referring to some advantageous examples only to which the invention is not to be narrowly limited. Many modifications and alterations are possible within the invention as defined in the following claims.

Claims

Pulper rotor (10) comprising a pulper rotor body (15), which has a center hub (12) and from the outer circumference of the center hub (12) extending a plurality of wings (14), which pulper rotor (10) further comprises a plurality of insert vanes (20), each of which insert vanes (20) is removably attached to the pulper rotor body (15) at the respective wing (14) thereof and which insert vanes (20) are attached to the pulper rotor body (15) by a formfitting attachment, characterized in that for the formfitting attachment the pulper rotor body (15) comprises for each insert vane (20) at least one key (19) and at least one groove (18), and each of the insert vanes (20) comprise correspondingly at least one key slot (28) and at least one protrusion (29), and that the keys (19) and the grooves (18) of the pulper rotor body (15) are formfitting with the key slots (28) and the protrusions (29) of the insert vanes (20).
Pulper rotor (10) according to claim 1, characterized in that each insert vane (20) has a blade (22) and a support element (21) and that the blade (22) extends upwards from the support element (21).
Pulper rotor (10) according to claim 1 or 2, characterized in that each insert vane (20) comprises at least one flange (23; 24) attached on the pulper rotor body (15) by a screw attachment.
Pulper rotor (10) according to any of claims 1-3, characterized in that each insert vane (20) comprises two flanges (23; 24) formed in the support element (21): a hub flange (23) and a wing flange (24) and that the hub flange (23) is attached on the center hub (12) of the pulper rotor body (15) by a screw attachment and that the wing flange (24) is attached on the wing (14) of the pulper rotor body (15) by a screw attachment.
Pulper rotor (10) according to any of claims 1-4, characterized in that the keys (19) and the grooves (18) of the pulper rotor body (15) are located at wings (14) of the pulper rotor body (15).
Pulper rotor (10) according to any of claims 1- 5, characterized in that the keys (19) are located at outer tip ends of the wings (14).
Pulper rotor (10) according to any of claims 1-6, characterized in that the keys (19) extend over less than half of the length of the wings (14).
Pulper rotor (10) according to any of claims 1-7, characterized in that the insert vanes (20) are made by casting.
Pulper rotor (10) according to any of claims 1-8, characterized in that the insert vanes (20) are of wear-resistant material, advantageously of martensitic or duplex stainless-steel.
Pulper rotor (10) according to any of claims 3-9, characterized in that for the screw attachment, the flange (23; 24) has screw openings (26; 27) and the pulper rotor body (15) has corresponding screw openings (16;17), through which openings (16, 26; 17, 27) screws or bolts are fastened.
Pulper rotor (10) according to any of claims 4-9, characterized in that for the screw attachment, the hub flange (23) has screw openings (26) and the pulper rotor body (15) has at the center hub (12) corresponding screw openings (16), through which openings (16, 26) of the center hub (12) and of the hub flange (23) screws or bolts are fastened, and the wing flange (24) has screw openings (27) and the pulper rotor body (15) has at the wings (14) corresponding screw openings (17), through which openings (17, 27) of the wings (14) and of the wing flange (24) screws or bolts are fastened.
Pulper rotor (10) according to claim 11, characterized in that the screw openings (26, 27) of the flange/-s (23, 24) have an upwards opening wider cavity (26A, 27A) for heads of the screws or bolts.
Pulper rotor (10) according to claim 12, characterized in that caps are provided for closing the cavities (26A, 27A), when the screws or bolts are in place.