CLEANING NOTCHES AND PASSAGES FOR A FEEDING OR REFINING ELEMENT

Abstract

A flinger or refiner plate for a mechanical refiner including deep notches or holes in feeder bars of the flinger plate and/or open passages or holes in bars of the refiner plate. The open passages and/or holes in the bars significantly reduce stagnate flow zones at the trailing side of the bars during operation of the mechanical refiner. The reduction of the stagnate flow zones may reduce or eliminate fiber accumulation at the trailing side of the bars.

Description

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application 62/635,143 filed Feb. 26, 2018, which is incorporated by reference in its entirety.

TECHNICAL FIELD

The invention relates generally to mechanical refiners and more particularly to flinger and refiner plates in such refiners, especially for pulping medium density fiberboard production and in mechanical pulping systems.

BACKGROUND

Mechanical refiners convert into pulp wood chips, recycled paper, recycled corrugated packaging material and other lignocellulosic materials (collectively referred to as “feed material”). The mechanical refiner applies pressure pulses, shearing forces and other mechanical forces to separate the feed material into separated fibers that form pulp. The feed material may have a high consistency, such as over 30% dry contents. High consistency cellulosic feed material may be refined to form medium density fiberboard (MDF) or mechanical pulps such as Thermo-Mechanical Pulp (TMP), Chemi-Thermo-Mechanical Pulp (CTMP) and other variations of pulp.

As the feed material flows through the refiner, fibers and extractives, such as resin, sap, pitch and other liquid or liquefied wood components in the feed material, tend to accumulate at certain locations in the refiner. These locations include the trailing side of feeder bars on flinger plates and the trailing side of dams between bars in refiner plates.

The accumulations of fiber and extractives become dark, e.g., black, and hard. Occasionally, the accumulations dislodge from the flinger and refiner plates, and enter the flow of feed materials moving through the refiner. The dislodged accumulations may break into small particles and mix into the flow of feed material. The particles of accumulations form dark specs in the pulp material output from the refiner and in the final product, being paper or board. Pulp material with dark specs reduces the final product's desirability and sales value. Accordingly, there is a long felt need to reduce dark specs in the pulp material produced by mechanical refiners.

SUMMARY

The inventors believe that the accumulations form due to low pressure regions next to trailing surfaces on the flinger and refiner plates. The low pressures are believed to cause stagnate flow of the feed material in what otherwise is a fast flow of materials through the refiner. Stagnate flow has low kinetic energy and thus low total pressure, as compared to the total pressure of fast flowing materials. Due to its low pressure, stagnate flow traps material that would otherwise flow through the refiner. The trapped material adheres to surfaces on the flinger and refiner plates adjacent the stagnate flow. These surfaces tend to be trailing surfaces of the bars of flinger plates, and trailing surfaces near or on dams in grooves of a refiner plate. The material remains trapped against the trailing surfaces and is blackened by the heat in the refiner.

The inventors conceived of a solution to the accumulations by increasing the pressures in stagnate flow regions. The pressure can be increased by creating notches and/or holes in the bars of a flinger plate and holes in the bars of a refiner plate. The notches and holes extend from a leading edge of a bar to a trailing edge of the bar. The notches and holes create a passage through the bar between a high pressure region at the leading side of a bar and a low pressure region at a trailing side of a bar.

The holes in the bars of a refiner plate open on a trailing side of the bar just behind a dam connected to the bar. Pressurized fluid, such as steam, flows through the holes to increase the pressure of the stagnant flow. The increased pressure should add energy to the stagnate flow regions and thereby reduce the tendency of fibers and other materials to accumulate behind dams and on the trailing sides of feeder bars.

The new designs of notches or holes in the bar of a flinger plate and holes in the bars of a refiner plate should reduce the low pressure that usually exists on the trailing side of feeder bars and downstream of dams in grooves between refining bars. The reduction in pressure differential may reduce or eliminate the fiber accumulations that occur in conventional flinger and plate designs by reducing or eliminating stagnate pressure zones.

An exemplary flinger plate or refiner plate in accordance with the present disclosure comprises deep notches or holes in the bars of the plate. The notches or holes in the bars allow steam to flow from the high pressure leading side of the bar to the low pressure trailing side of the bar.

The notches or holes in or through a bar of a flinger or refiner plate may be oriented to reduce the fiber entrained with the steam flowing through the notches or holes. To reduce the fibers in the steam flowing through the bars, the notches or holes may be aligned perpendicularly to the bars, or at an acute or obtuse angle to the bars.

An exemplary flinger plate for a mechanical refiner may comprise: a front face, a back face, a substrate separating the front face from the back face, a center hub extending from the front face, feeder bars extending from the front face, wherein the feeder bars extend radially outward along the front face from the center, a deep notch or hole disposed in a feeder bar of the feeder bars. The deep notch or hole extends through the bar and is configured to allow fluid to flow through the bar. The deep notch or hole may be oriented to reduce the likelihood that fiber will travel through the deep notch when the flinger plate is used in a mechanical refiner.

The notch may have an opening at a leading side of the feeder bar or refiner bar that has a cross-sectional area which is smaller than a cross-sectional area of an outlet of the notch at the trailing side of the bar. Similarly, the cross-sectional area of the notch may gradually increase from the inlet to the outlet of the notch. Similarly, hole(s) in each bar may have an opening at a leading side of the bar that has a cross-sectional area smaller than a cross-sectional area of an outlet of the hole at the trailing side of the bar. The cross-sectional area of the hole may gradually increase from the inlet to the outlet of the hole. The holes may be an alternative to the notches or used in addition to the notches. For example, notches may be in bars on a flinger plate and holes may be bars on a refiner plate in the same refiner.

A mechanical refiner plate segment has been conceived and is disclosed herein which includes: a substrate having a radially inward edge and a radially outward edge; a refining surface including bars separated by grooves, wherein the bars and grooves extend towards the radially outward edge; dams in the grooves, wherein the dams in each groove span between the adjacent bars on opposite sides of the groove; and at least one open passage extending through one of the adjacent bars, wherein the open passage has one end adjacent or near a trailing side of one of the dams in the groove.

The mechanical refiner plate segment may have an open passage with a cross sectional area of at least nine (9) mm² for an entirety of a length of the open passage. The open passage may be below a ridge of the one of the adjacent bars by at least 10%, or 15%, or 25% of the height of the one of the adjacent bars. The open passage may have an inlet at a leading side of the refiner bar that has a cross-sectional area smaller than a cross-sectional area of an outlet of the passage at the trailing side of the bar. Similarly, the cross-sectional area of the open passage may gradually increase from the inlet to the outlet. Also, there may be an open passage associated with each of the dams in the refiner plate segment.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particular description of exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. The drawings are not necessarily to scale, with emphasis instead being placed upon illustrating the disclosed embodiments.

FIG. 1 is a cross sectional schematic drawing of a portion of a mechanical refiner machine for pulping cellulosic feed material.

FIG. 2 shows a front face of a flinger plate.

FIG. 3 is a cross-sectional view of the flinger plate shown in FIG. 2 taken along the line 3-3 in FIG. 1.

FIG. 4 is a front view of a refiner plate segment.

FIG. 5 is side view of a portion of a cross section of the refiner plate segment shown in FIG. 4.

DETAILED DESCRIPTION

FIG. 1 shows in cross section a conventional single-disc refiner 10 having a housing 12 defining an internal chamber 14. A rotor disc assembly 16 in the chamber is turned by a shaft 18 driven by a motor. The rotor disc assembly includes a supporting disc 20, a circular flinger plate 22 attached to a front face of the supporting disc 20, and an annular assembly of pie-shaped refiner plate segments 24 mounted to the front face of the supporting disc 20. Inner edges of the refiner plate segments are adjacent an outer periphery of the flinger plate 22.

A similar annular array of plate segments 26 is arranged on a supporting disc 28 of a stator disc assembly which is fixed to housing. Alternatively, an annular refiner plate may be used instead of an annular array of plate segments. Further, the refiner plates or plate segments may be arranged in a disc generally conforming to a plane for a disc refiner or as a frustoconical plate or a frustoconical assembly of plate segment for a conical refiner.

The flinger plate 22 rotates with the rotor disc assembly 16. The flinger plate accepts feed material from a cellulosic material feeding screw (not show). Feed material flows from the material feed screw, through at center inlet 30 to the refiner along a flow direction (F) parallel to an axis 32 of rotation of the rotor disc 16. The flinger plate 22 assists in turning the flow of the cellulosic material from an axial direction 32 to a radial direction that leads a gap 34 between the rotor disc assembly and the stator disc assembly. If the refiner disc is conical, the flinger plate assists in turning the flow to a conical path that leads to a conical gap between conical refiner plates.

As the feed material moves through the gap 34, the material is refined by bars and grooves on the opposing plate segments 24, 26 of the rotor and stator plate assemblies. The action of the bars and grooves separates the feed material into fibers and thus into pulp. The pulp flows out of the outer periphery of the gap 34 and into the chamber 14 of the housing 12.

FIG. 2 is a front view of a flinger plate 100 for a mechanical refiner comprising feeder bars and deep notches 118, 124 disposed within the feeder bars. The deep notches may be oriented to reduce the likelihood that fiber will travel into and across the notch. FIG. 3 is a side view of a cross section of the flinger plate 100.

The flinger plate 100 includes a substrate 102 having a front face 104 and a back face 105 on an opposite side of the substrate. The flinger plate 100 has a center axis (C) and a center hub 106 centered on the axis. The center hub may protrude from the front face 104 of the substrate and has a planar (flat) face. Alternatively, the center hub 106 may be planar with the front face 104 of the substrate or recessed with respect to the front face of the substrate.

An outer annular periphery 108 of the flinger plate 100 defines the outer edge of the substrate 102. The flinger plate 100 may be a single circular disc or an assembly of pie-shaped plate segments that together form a circular disc.

Feeder bars 110 protrude from the front face 104 and extend from the center hub 105 to the outer periphery 107. The feeder bars 110 are swept back from a radial line in a rotational direction R. The back sweep of the feeder bars 110 aids in flinging feed material radially outward. The flinger plate 100 and rotor disc assembly rotate in direction R. The bars can also be straight, either angled in a feeding angle, or arranged in a substantially radial direction. The flinger plate 100 is secured to the rotor disc 16 by fasteners (not shown) that extend through fastener holes 120 in the substrate 102.

The feeder bars 110 each have a leading side 112, a trailing side 114 and a wide ridge 116 spanning between top edges of the leading and trailing sides. Notches 118 extend through feeder bars 110 to form grooves extending from the ridge 116 down towards and possibly to the substrate 104. Each feeder bar may have one, two, three or more notches 118 and/or holes 119. The inlet 122 to each of the notches or holes is on the leading side 112 of the feeder bar 110 and the outlet 124 is on the trailing side 114 of the feeder bar. A radially inward notch 118 or hole 119 on each feeder bar may have an outlet 124 adjacent the center hub 106.

The notches or grooves may be grouped along the first half or two-thirds of the radial length of a feeder bar. The depth of the notches may be from the ridge 116 down half way of the bar to the substrate, two-thirds to the substrate or all the way to the substrate 104. The notch may extend into the substrate. Similarly, the holes 119 may extend into the substrate.

The notches or holes may be arranged such the inlet 122 is at a shorter radial distance from the center (C) than the outlet 124. The notches or holes may also be perpendicular to the bars, or have a reversed direction wherein the inlet is at a greater radial distance than the outlet.

The cross-sectional area of the inlet 122 to a notch 118 or hole 119 may be smaller than the cross-sectional area of the outlet 124. Similarly, the cross sectional area of a notch or hole may gradually, e.g., linearly, increase in area from the inlet 122 to the outlet 124.

The notches 118 and holes 119 allow fluid, such as steam, under pressure at a leading side 112 of the feeder bar to pass through the bar to the trailing side 114. The pressure at the leading side 112 of a feeder bar 110 tends to be greater than the pressure at the trailing side 114 due to the movement of the leading side into the feed material and the movement of the trailing side away from the feed material.

The greater pressure at the inlets 122 of the notches or holes will cause fluids, such as steam, to move through the notches and to the trailing side 114 of the feeder bars. As the fluid exits the notches, the relatively higher pressure of the fluid increases the pressure at the trailing side 114 of the feeder bars. This increased pressure at the trailing sides 114 reduces the tendency of stagnate flow forming in relatively low regions adjacent the trailing sides 114 of the feeder bar.

The notches 118 or holes 119 may be shaped to suppress fibers being drawn into the inlets 122 of the notches. The shape of the inlets 122 may include an obtuse angle, a curvature along the length of the notches or a hole, and an acute angle 128 at the outlet 124. The obtuse angle 126 may be in a range of 100 degrees to 160 degrees, 115 to 145 degrees, or some other degree. The obtuse angle may be measured at the radially inward edge 130 of the inlet 122. The obtuse angle causes flow moving in front of the leading side 112 of the feeder bar 110 to turn greater than 90 degrees to enter the inlet 122. The flow that makes this turn should be primarily liquids and not the fibers in the flow. The obtuse angle 126 at the inlet 122 also results in a blunt edge at the radially outward side of the inlet. The blunt edge reduces the risk that fibers impacting the edge are cut or otherwise damaged.

At the outlet 124, the acute angle 128 may be measured at the radially inward 132 edge of the outlet 124. The acute angle 128 may be in a range of 90 to 30 degrees, 75 to 45 degrees or in another range of degrees. The curvature along the length of the notches 118 or hole 119 provides a smooth transition between the angles of the inlet and outlet to the notch. The angles of the channels are may be selected to prevent preventing feed material moving across bars and thus create a loss in the feeding performance. On the other hand, notches or holes that run perpendicular to the bars, or even in a direction towards the outer periphery of the flinger plate may be desirable in certain cases.

The sidewalls of the notches 118 or holes 119 may be planer and perpendicular to the substrate 102 or angled such that the notch opens from the substrate to the ridge 116. The sidewalls may also be curved, such as concave or convex, from the substrate to the ridge.

The holes may be 119 similar to the notches 118, except that the ridge extends over the holes but not over notches. The holes may be individual holes 119 through a feeder bar, two or more holes that join at their inlet or outlets, and the holes may be tapered such that their cross-sectional area increases from inlet to outlet. The holes function similarly to the notches to provide pressure equalization across the leading and trailing sides of a bar in a flinger plate.

The notches 118 or holes 119 may each have a cross sectional area of at least 9 mm² and may have a width less than the width of the feeder bar with the notch (or holes). The width of the notch or hole is from one side of the notch or hole to an opposite side. The width may be constant along the length of the notch or hole, except at the inlet and outlets may expand. The notches or holes may also have a variable width, such as being narrow on the leading edge of the bars, and extending towards the trailing edge of the bars. This prevents large particles of the feed material to enter the notches or holes, but also reduces the risk of blocking the inlets s with material.

The flinger plate 100 may be formed by casting metal into a mold form of sand. An imprint of the flinger plate is formed in sand molds which are clamped together to form a cavity that is substantially the same shape as the flinger plate. Metal is poured in the cavity of the sand mold to form the flinger plate. The flinger plate can also be cast without the notches, and notches can be made through machining of the bars with suitable tools. The flinger plate can also be a manufactured plate made of individually welded components. Holes can be drilled, cast using cores in the pattern, or made with 3D printed sand molds. Holes can also be made in bars prior to making a welded assembly.

FIG. 4 is a front view of a refiner plate segment 200, and FIG. 5 is side view of a portion of a cross section of the refiner plate segment 200. The refiner plate segment 200 may be conventional except for the holes in the bars described below.

The refiner plate segment 200 is pie-shaped and is assembled with other refiner plate segments on a rotor or stator disc. The refiner plate segments are attached to the disc by fasteners inserted in fastener holes 202. The refiner plate segments are arranged side 204 to side to form an annular assembly of segments on the disc. The outer edge 206 of the refiner plate segment 200 forms a circular perimeter when the plate segments are arranged in the annular assembly. The outer edge 206 of the refining surface of the refiner plate segment. The inner edge 208 of the refiner plate segment 200 may be located on the rotor or stator disc adjacent an outer edge of the flinger plate. The inner edges 208 of the assembly of refiner plate segments 200 form a circle that surrounds the outer edge of the flinger plate.

The front face of the refiner plate segment 200 is a refining surface. The front face includes a substrate 210 that extends between the inner and outer edges 206, 208, and between the sides 204 of the refiner plate segment. The substrate may be planar from a disc refiner, or the substrate may be arched for a conical refiner.

Extending outward from the substrate 210 are bars 212, 214 and 216 arranged in groups. The radially inward most group of bars 212 are thick and spaced relatively far apart. The next group of bars 214 are narrower and relatively close together, and radially outermost bars 216 are the narrowest and most closely spaced together. The bars in each group may be substantially parallel. Between adjacent bars are grooves that extend down to the substrate 210 and up to the top (ridge) of the bars. The bars and grooves in each group define a refining sections of the refiner plate segment. The arrangements of groups of bars and grooves shown in FIG. 4 is exemplary. Other refiner plates may have a single group of bars and grooves, two or more groups or bars and grooves that vary in shape and dimensions in a radial direction of the refiner plate.

The feed material flows radially outward through a gap 34 (FIG. 1) between the front faces of opposing refiner plates or assembly of plate segments. The opposing refiner plates or assembly of plate segments may be a refiner plate assembly and a stator plate assembly. Some refiners may have two oppositely rotating discs on either side of the gap. The bars and grooves of one plate assembly face the bars and grooves on the opposing plate assembly. The bars and grooves refine the lignocellulosic matter in the feed material by applying pressure pulses and by shearing the matter.

The grooves 217 between bars 212 in the inner refining zone, the grooves 218 between bars 214 in the middle refining zone and the grooves 220 between bars 216 is the outer refining zone provide passages for steam and liquids to flow radially outward. While fibers also may flow through the grooves, the fibers are refined by flowing over the bars and in the gap between the refiner plates.

To move the fibers out of the grooves and to slow the flow through the grooves, dams 222, 224, 226, 228 fully or partially block the grooves. Specifically, partial-height dams 222 and full height dams 224 are placed are at various locations in the grooves between the bars 214. Similarly, partial height dams 228 and full height dams 226 are at various locations between the bars 216.

As shown in FIG. 5, partial-height dams 222, 228 extend from the substrate 210 towards the ridge 230 of the bars, but do not reach the bars. Full height dams 224, 226 extend from the substrate to the ridge of the bars. The dams divert material flowing through the grooves towards the gap between the opposing refiner plate assemblies. The dams also slow the flow of material through the grooves.

The dams create stagnate flow zones 232 in the grooves immediately downstream (radially outward) of the dams. Stagnate flow zones collect fibers and other particles due to the low pressures in the zones. These fibers and particles can adhere to the back of the dams and the sides of the bars near the dams. The accumulations of fibers, pitch and other particles tend to become hard and blacken due the high temperatures in the refiner. The accumulations may periodically break off into small black particles that can contaminate and discolor the pulp (separated fibers) being produced by the refiner. The accumulations also may fill the grooves and thereby reduce the ability of the refiner plates to refine material and reduce the feed material capacity of the refiner. Thus, the accumulations may require replacement of the refiner plate segments.

To reduce the accumulations behind dams, open passages 234 are formed in the bars and are each positioned radially outward of a dam. The open passages 234 allow fluid to flow from a high pressure in a region of one groove away from a dam through a bar and into a stagnate zone to increase the pressure in that zone. The increased pressure reduces the tendency for accumulations to form and thereby reduces the risk that particles of accumulations will break off and contaminate the pulp. There may be an open passage 234 associated with each dam such that the outlet of the passage 234 is immediately downstream (radially outward and adjacent the trailing side) of the dam and the inlet opens to a portion of a groove that does not have a dam. The downstream direction of the feed material is shown by arrow 236 in FIG. 5.

The open passages 234 are below the ridge 230 of the bar. The ridge of the bar applies shear and pressure pulses to the feed material. A continuously ridge over the open passages 234 allows the ridge to continue applying shear and pressure forces. Adding a notch to the ridge to provide a passage through the bar would interrupt the ridge and reduce the ability of the bar to refine the feed material.

The open passage 234 may extend down to the substrate 210 as shown in FIG. 5 or may in a mid-section of a bar and not reach the substrate. The open passage may extend towards the ridge of the bar but should not interrupt the ridge. There may be a substantial portion of the groove, such as a quarter of the grooves height, between the ridge and the open passage. Leaving a substantial portion between the ridge and open passage will allow the ridge to erode without eroding into the open passage. The open passage may also be partially or fully below (inside) the substrate.

The open passage 234 may have a cross section that is square, rectangular, circular, oval, or any shape that allows steam or other fluids/material to flow from one groove into the next groove. The cross sectional area of the open passage may be 9 mm² or at least grater than 7 to 8 mm². For example, an open passage 234 may have a square cross of 3 mm×3 mm. The open passages 234 should not be too small, such as below 7 mm² to avoid plugging of the passage with material. Similarly, the open passages 234 should not be so large as to weaken the ridge or the bar. Open passages 234 having a dimension of 3 mm to 5 mm in a direction from the substrate to the ridge may be advantageous in provide a large opening and not weakening the ridge.

Moreover, the passages 234 may extend into the substrate such that a portion of the passage extends through the bar and a parallel portion is embedded in the substrate, as shown in FIG. 5. Alternatively, the passages 234 may be entirely embedded in the substrate such that the passage extends below a bar and have the inlet and outlet at the bottom of the grooves on opposite sides of the bar.

The open passages 234 may be perpendicular to the longitudinal axis of the bar, or may be acute to the longitudinal axis. Moreover, the cross sectional area of the open passage may be constant along its length, or may be tapered from the inlet to the outlet (or vice versa) to achieve a desired flow of steam and other fluids through the passage.

The refiner plate segment 200 may be formed by casting metal into a mold form of sand. An imprint of the refiner plate segment is formed in sand molds which are clamped together to form a cavity that is substantially the same shape as the flinger plate. Metal is poured in the cavity of the sand mold to form the flinger plate. The open passages may be formed in the sand molds by three-dimensional printing all or a portion of the sand imprint for the refiner plate segment. Additionally, the open passages may be made after the production of castings using drilling and machining processes, or standard sand castings can have sand cores added to create the open passages directly in the casting.

Except as otherwise expressly stated herein, the following rules of interpretation apply to this specification: (a) all words used herein shall be construed to be of such gender or number (singular or plural) as to circumstances require; (b) the singular terms “a,” “an,” and “the,” as used in the specification and the appended claims include plural references unless the context clearly dictates otherwise; (c) the antecedent term “about” applied to a recited range or value denotes an approximation within the deviation in the range or values known or expected in the art from the measurements; (d) the words “herein,” “hereby,” “hereto,” “hereinbefore,” and “hereinafter,” and words of similar import, refer to this specification in its entirety and not to any particular paragraph, claim, or other subdivision, unless otherwise specified; (e) descriptive headings are for convenience only and shall not control or affect the meaning or construction of any part of the specification; and (f) “or” and “any” are not exclusive and “include” and “including” are not limiting. Further, the terms, “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including but not limited to”).

Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range of within any sub ranges there between, unless otherwise clearly indicated herein. Each separate value within a recited range is incorporated into the specification or claims as if each separate value were individually recited herein. Where a specific range of values is provided, it is understood that each intervening value, to the tenth or less of the unit of the lower limit between the upper and lower limit of that range and any other stated or intervening value in that stated range or sub range hereof, is included herein unless the context clearly dictates otherwise. All subranges are also included. The upper and lower limits of these smaller ranges are also included therein, subject to any specifically and expressly excluded limit in the stated range.

Claims

1. A mechanical refiner flinger plate comprising:

a front face;

a back face;

a substrate separating the front face from the back face;

a center hub extending from the front face;

feeder bars extending from the front face, wherein the feeder bars extend radially outward from the center; and

a deep notch or hole disposed in a feeder bar of the feeder bars, wherein the feeder bar has an area defining the deep notch or hole, and the deep notch or hole extends through the feeder bar and is configured to allow fluid to pass through the feeder bar.

2. The mechanical refiner flinger plate of claim 1, wherein the feeding bar further comprises a leading side and a trailing side distally disposed from the leading side, wherein the deep notch or hole further comprises a first end distally disposed from a second end, and wherein the first end is disposed radially outward from the second end.

3. The mechanical refiner flinger plate of claim 1, wherein the deep notch or hole includes multiple deep notches or holes disposed in the feeder bar.

4. The mechanical refiner flinger plate of claim 1, wherein the deep notch or hole is disposed in each of the feeder bars.

5. The mechanical refiner flinger plate of claim 1, wherein the deep notch or hole includes multiple deep notches and/or holes, at least one of which is disposed in each of the feeder bars.

6. The mechanical refiner flinger plate of claim 1, wherein the deep notch or hole further comprises a radially outermost edge at the first end of the deep notch or hole, wherein the radially outermost edge forms an obtuse angle between the adjacent notch or hole sidewall and the leading side of the feeder bar.

7. The mechanical refiner flinger plate of claim 1, wherein the deep notch or hole further comprises a radially outermost edge at the first end of the deep notch or hole, wherein the radially outermost edge is selected from a group consisting of a chamfer, a bevel, and a curve.

8. The mechanical flinger plate of claim 1, wherein the notch extends through the feeding bar and partially into the substrate, or the hole is partially embedded in the substrate.

9. A mechanical refiner plate segment comprising:

a substrate having a radially inward edge and a radially outward edge;

a refining surface including bars separated by grooves wherein the bars and grooves extend towards the radially outward edge;

dams in the grooves, wherein the dams in each groove span between the adjacent bars on opposite sides of the groove; and

at least one open passage extending through one of the adjacent bars, wherein the open passage has one end adjacent a trailing side of one of the dams in the groove.

10. The mechanical refiner plate segment of claim 9, wherein the open passage has a cross sectional area of at least nine (9) mm2 for an entirety of a length of the open passage.

11. The mechanical refiner plate of claim 9, wherein the open passage is separated from a ridge of the one of the adjacent bars by at least 10%, or 15%, or 25% of the height of the one of the adjacent bars.

12. The mechanical refiner plate segment of claim 9, wherein the bars and grooves extend from one side edge of the substrate to an opposite side edge of the substrate.

13. The mechanical refiner plate segment of claim 9, wherein there is one of the open passages associated with at least 50% of the dams in the refiner plate segment.

14. The mechanical refiner plate segment of claim 9, wherein the refiner plate segment is formed of a cast metal.

15. The mechanical refiner plate segment of claim 9, wherein the refiner plate segment has a pie-shape and is configured to be arranged with additional refiner plate segments to form an annular refiner plate.

16. The mechanical refiner plate segment of claim 9, wherein the refiner plate segment is a portion of an annular refiner plate.

17. The mechanical refiner plate segment of claim 9, wherein the radially inward edge is configured to be adjacent an outer periphery of a flinger plate.

18. The mechanical refiner plate segment of claim 9, wherein the at least one open passage is at least partially embedded in the substrate below the one of the adjacent bars.