KR20010106424A - Refiner plate steam management system - Google Patents

Abstract

The purifier plate for the face of the purifier disc consists of a plurality of purifier segments 10 arranged side by side on the face of the disc to form a substantially annular purifying zone. Each refiner segment has a plurality of bars 40 and grooves 34 that form a path for purifying wood fiber material and receiving and delivering vapor generated during the purification process. A plurality of dams 46 are disposed in the grooves to retard the motion of the wood fiber material. The partial height portion of each dam adjacent to the trailing surface of the bar provides a flow path for the steam.

Description

Purifier Plate Steam Treatment System {REFINER PLATE STEAM MANAGEMENT SYSTEM}

In a highly consistent mechanical pulp refiner, wood fibers are worked between two relatively rotating discs, on which a refiner plate is mounted. The plate generally has radial bars and grooves. As a result of this purification operation a large volume of steam is produced between the plates. For effective purification, the fibrous material must remain on the bar surface between the plates, despite the high velocity of the flowing vapor, and the very high centrifugal force. Typically, steam is discharged through the grooves. A dam extending to the bar surface is provided in the groove to block the flow of material and thus improve the retention time of the material in the refining zone.

In typical refiner plates with radial bars and grooves, the bars provide shock or pressure pulses that separate the fibers and break them down into fine fibers. The grooves allow for radially induced transport and vapor extraction of the fibers. Near the periphery of the plate, a large radial vapor flow and a large centrifugal force act to blow the fiber too early outwards between the plates, thus reducing the purification effect. The flow restriction due to the small gap between the opposing plate and the fiber full groove leads to a vapor pressure peak between the plates, located radially inward from the periphery. These pressure peaks are a major source of refinery thrust loads and can cause control instability at high motor loads. Thus, the steam generated during purification is withdrawn from the purification zone as quickly as possible, while keeping the pulp in the purification zone as long as possible.

Although surface dams promote more and more homogeneous purification and help the pulp pads develop between the segments, they inhibit the flow of steam in the grooves. Reduced vapor flow leads to higher pressure peaks, resulting in greater thrust and instability.

The present invention relates generally to disk refiners for wood fiber materials. In particular, the present invention relates to purifier plate segments for such devices.

1 is a front view of a purifier plate segment having a steam treatment system according to the present invention;

FIG. 2 is an enlarged front view of part 2 of FIG. 1;

3 is an enlarged cross sectional view along line 3-3 of FIG. 1;

4 is an enlarged cross sectional view along line 4-4 of FIG. 1;

5 is an enlarged front view of an alternative embodiment of the surface dam and bar of FIG.

6 is a front view of an alternative embodiment of the purifier plate segment of FIG. 1; And

7 is an enlarged cross sectional view along line 7-7 of FIG. 6;

In short, the present invention is a refiner plate segment for purifying wood fiber material. The purifier plate segment is alternating and has a purifying zone comprising a plurality of bars and grooves disposed substantially radially. Each of the bars has a normal grinding surface, a leading surface and a trailing surface. At least one dam extends radially across the groove in the middle of the leading bar and trailing bar pair of bars. The dam includes a first portion extending from the trailing surface of the leading bar and a second portion extending from the leading surface of the trailing bar. Each portion of the dam has a top surface, wherein the top surface of the second portion is substantially coplanar with the top surface of the bar and the top surface of the first portion is disposed between the top surface of the bar and the base of the groove.

Preferably, a plurality of dams are arranged in each of the grooves. In one embodiment, the top surface and trailing surface of the leading bar form a cavity disposed adjacent to the first portion of the dam. The cavity has a bottom that creates an arcuate segment on the trailing side of the leading bar and is substantially coplanar with the top surface of the first portion of the dam, thereby reducing the possibility of causing turbulence in the flow of material.

It is an object of the present invention to provide a purifier plate for the face of the purifier disc, which facilitates the removal of steam while maintaining the pulp in the purifier region to achieve satisfactory pulp quality.

It is a further object of the present invention to provide a purifier plate for the face of the purifier disc, leading to the material to be purified onto the tablet surface of the disc.

Other objects and advantages of the present invention will become apparent from the drawings and the specification.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood and numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings.

Referring to the drawings, wherein like reference numerals refer to like elements throughout the several views, a purifier plate having a steam treatment system according to the present invention is a plurality of purifier plate segments 10 that can be fastened to the front face of a generally circular purifier disc 12. ) (See FIG. 3). Although in the illustrated embodiment each segment 10 has two zones 14 and 16 and each zone has a series of patterns oriented differently, each segment 10 has one zone, each It may optionally have three or more zones having a series of patterns of (see FIG. 1).

The plate segment 10 is attached to the disk face in any convenient or conventional manner, for example by bolts (not shown) passing through the bore 18. One end of the bolt engages the disk and the other end has a head structure that is supported in contact with the countersunk surface 20. The disk 12, which is shown only in part, has a central portion, with the disk rotating around the central portion, having a substantially circular outer circumference. The purifier plate segment 10 is arranged side by side on the face of the disc 12 to form a substantially annular purifier face 22, generally shown by reference numeral 22 (see FIG. 3). When faced with another purifier plate (not shown) held by another disk, the purifier face 22 forms part of the purifier region.

1, each purifier plate segment 10 has an inner edge 24 near the center of the disk, an outer edge 26 near the outer periphery of the disk, and leading and trailing sides of adjacent purifier plate segments. It has trailing and leading side edges 28 and 30, respectively, in contact with the edges. Although the following description will refer to one plate segment 10, it should be understood that all segments 10 forming an annular plate are preferably substantially identical. The plate segment 10 has at least one, and preferably two or three, separate patterns of bars 32 on the face and grooves 34 between the bars, whereby the material to be purified is It can flow in the groove in a general direction from the inner edge 24 of the plate segment 10 to the outer edge 26. The bars 32 and grooves 34 extend substantially radially, ie radially or parallel to the radius of the disk 12 or at an acute angle to this radius.

The first or inlet zone 14 has a plurality of bars 36 and grooves 38 between adjacent bars 36, all of which extend substantially radially. This pattern is particularly suitable for receiving wood chips, wood pulp and the like and performing initial refining operations on the pattern to reduce the size of the material and radially outflow to the second or refining zone 16. The refining zone 16 has a plurality of bars 40 and grooves 42 between the adjacent bars 40, which also extend in parallel and substantially radially. A third zone or outer zone may be provided between the outer edge 26 of the plate and the purification zone 16. As shown in FIG. 1, each zone 14, 16 may be comprised of a plurality of fields 44, 44 ′, each field 44, 44 ′ having a uniform pattern. In the embodiment shown in FIG. 1, segment 10 has two fields 44, 44 ′ in each zone 14, 16. The pattern promotes the flow of steam radially outward to the outer edge of the disc and radially inward to the inner edge of the disc for evacuation while retarding the flow of material to ensure that the material is fully purified.

As the disk 12 and plate rotate, as a result of the centrifugal force, the partially purified material is directed radially outward. A significant amount of steam is also generated in the refining zone 16 which produces a large radial velocity steam flow. In particular, for relatively large discs, the centrifugal forces acting on the vapor and the chips to be partially refined increase dramatically as the material moves further radially outward. Although it is very desirable for the steam to be expelled from the refining zone quickly, essentially the partially refined fibers are not discharged quickly along the steam. This condition is affected by the radial pressure profile along the disk face due to the vapor generated by the refinement at high consistency. Since the pressure peak is between the inner and outer edges 24 and 26 of the plate, the steam is directed forward (radially outward) and from the inside of the pressure peak back (radially out) from the outside of the pressure peak, against material transfer. Inside).

1 to 4, the refining zone 16 of the first embodiment of the refiner plate segment 10 includes a plurality of partial dams 46 disposed in each of the grooves 42. 46 shows the full height portion 48 and the base 58 of the groove 42 and the bar 40 having a top surface 50 that is substantially coplanar with the top grinding surface 52 of the bar 40. And a partial height portion 54 having a top surface 56 disposed in the middle of the top surface 52. The full height portion 48 of the trailing bar 62 adjoins the point P in the middle of the trailing edge 66 of the leading bar 68 adjacent to the leading edge 64 of the trailing bar 62. It extends from the leading surface 60. The partial height portion 54 extends from point P to the trailing surface 70 of the leading bar 68. The relative width of the full height portion 48 and the partial height portion 54, the height of the partial height portion 54, and the height of the partial dam 46 depend on the properties of the material being refined and the degree of purification desired. For example, as shown in FIG. 3, point P may be substantially midway between leading edge 64 of trailing bar 62 and trailing edge 66 of leading bar 68. The partial height portion 54 may extend to a substantially intermediate height of the groove 42.

Fibers or materials in the grooves 42 tend to move along the leading surface or face 60 of the trailing bar 62. Therefore, the full height portion 48 is located adjacent the leading face 60 of the trailing bar 62 to block the flow of material through the grooves 42 and into the gap between the opposing purifiers for further purification. Raise these materials. As shown in FIG. 4, dam 46 may have a radially extending ramp face 72 to direct material out of groove 42 and into the gap. Vapor flowing through the passage 74 provided by the partial height portion 54 adjacent to the trailing face 70 of the leading bar 68 carries very little material. Therefore, the amount of material bypassing each partial dam 46 is very small.

Referring to FIG. 5, the cavity 76 extends the cross-sectional area of the passage 74 ′ formed by the partial height portion 54 of the dam 46 by removing the trailing portion of each leading bar 68 ′. ) May be formed. The cavity 76 preferably forms an arcuate trailing face segment 78 adjacent the partial dam 46. This shape may allow additional material to be entrained in the steam passing through the flow passage 74 'to minimize turbulent flow inside the partial dam 46. Similarly, the bottom surface 80 of the cavity 76 is substantially coplanar with the top 56 of the portion height portion 54 to provide a relatively smooth surface that minimizes turbulence. The additional flow area provides a vapor flow that increases with little or no additional bypass flow of material.

US patent application Ser. No. 08 / 886,310, filed June 1, 1997, discloses a purifier plate having a variable pitch. One or more fields in the refining zone of such a purifier plate may have a combination of wide and deep grooves 82 and shallow narrow narrow grooves 84. The wider and deeper grooves 82 provide a larger cross sectional area for the flow of steam. The blade 86 produced by the small groove 84 forms an additional grinding surface and causes additional vibration during the refining operation, which increases the grinding efficiency of the refiner disk. 6 and 7, the variable pitch purifier also includes a partial dam 46 'in accordance with the present invention. The small groove 84 does not occupy a major part of the steam flow. Therefore, the partial dam 46 ′ is only located in the wide groove 82. Each dam 46 'has a full height portion 48' and a top surface of the blade 86 having a top surface 50 'that is substantially coplanar with the top grinding surface 52' of the blade 86. And a partial height portion 52 'having a top surface 56' disposed between the base 52 'of the wide groove 82 and 52'.

While the preferred embodiments have been shown and described, various modifications and substitutions may be made without departing from the spirit and scope of the invention. For example, the present invention may be advantageous to have three zones. Accordingly, it should be understood that the present invention has been described by way of example and not limitation.

Claims (14)

A plurality of bars having a top surface, a leading surface and a trailing surface, respectively, and forming a plurality of bar pairs including leading and trailing bars, the plurality of bars being substantially radially disposed; A plurality of grooves each forming a base, alternating with said bars; A first portion extending from the trailing surface of the leading bar and a second portion extending from the leading surface of the trailing bar, wherein the first portion and the second portion of the dam each have a top surface The top surface of the second portion is disposed substantially coplanar with the top surface of the trailing bar and the top surface of the first portion is between the top surface of the leading bar and the base of the groove. At least one dam disposed radially across the groove in the middle of the leading and trailing bars of at least one pair of bars; A refiner plate segment for purifying wood fiber material, characterized in that it comprises a refining zone having. The refiner segment of claim 1, wherein at least one of the dams is disposed in each of the grooves. 3. The refiner segment of claim 2, wherein a plurality of said dams are disposed in each of said grooves. 2. The refiner segment of claim 1, wherein the top surface of the leading bar and the trailing surface form a cavity disposed adjacent the first portion of the dam. 5. The refiner segment of claim 4, wherein the trailing surface of the leading bar comprises an arcuate segment that forms the cavity. 5. The refiner segment of claim 4, wherein the cavity has a bottom substantially coplanar with the top surface of the first portion of the dam. Having a relatively rotating opposed disk forming a tablet gap, each of which retains a plate formed by a plurality of plate segments for purifying wood fiber material, each plate segment being substantially radially disposed; A plurality of bars, a plurality of grooves alternating with the bars, and a plurality of dams extending radially across the grooves, each of the bars having a top surface and forming a plurality of bar pairs comprising leading and trailing bars; And each of the grooves has a base, each of the dams including a first portion disposed adjacent to the leading bar and a second portion disposed adjacent to the trailing bar, wherein the first portion and the second portion of the dam Each of the portions has a top surface and the top surface of the second portion is trailing. And a top surface of the first portion disposed substantially coplanar with the top surface of the bar and between the top surface of the leading bar and the base of the groove. 10. The method of claim 7, wherein each of said bars further has a leading and trailing surface, said first portion of said dam extending from said trailing surface of said leading bar to a point halfway between said leading and trailing bars and said And a second portion extends from said point to said leading surface of said trailing bar. 8. The purifier of claim 7, wherein each of the dams has a sloped leading surface that extends radially to direct material into the purification gap. 8. The refiner segment of claim 7, wherein said leading bar defines a cavity disposed adjacent said first portion of said dam. 11. The refiner segment of claim 10, wherein each of said bars further has a leading surface, and said trailing face of said leading bar comprises an arcuate segment forming said cavity. 12. The refiner segment of claim 11, wherein the cavity has a bottom substantially coplanar with the top surface of the first portion of the dam. 8. The refiner segment of claim 7, wherein each of the top surfaces of the plurality of bars form at least one substantially radially disposed small groove, wherein none of the dams are disposed in the small groove. . During the purification of the wood fiber material in the refiner, a flow of transfer material and steam occurs between a pair of relatively rotating opposed tablet discs forming a tablet gap, each of which has a radial inner and outer edge, And a surface pattern comprising a refining zone having a plurality of bars arranged radially, the plurality of grooves alternating with the bar, and the plurality of dams extending radially across the groove, each of the bars grinding the top. A plurality of bar pairs having a surface and comprising a leading bar and a trailing bar, each groove having a base, each dam having a first portion disposed adjacent to the leading bar and a first portion disposed adjacent to the trailing bar. And two portions, each of the first portion and the second portion of the dam having an upper surface. Wherein the second portion of the dam has an inclined leading surface, wherein the upper surface of the second portion is disposed substantially coplanar with the upper surface of the trailing bar and the upper surface of the first portion Is disposed between the upper surface of the leading bar and the base of the groove, the first portion, the second portion and the upper surface of the leading bar form a vapor flow passage, 1) directing the conveying material over the inclined leading surface of the second portion of the dam into the purification gap with centrifugal force generated by rotating the at least one purification disk for grinding on the grinding surface of the bar; And 2) directing steam through grooves and vapor flow passages to the outer edge of the disk by centrifugal force thereby removing the steam from between the disk; Method comprising a.