Defibrating apparatus and fiber body manufacturing apparatus

A defibrating apparatus includes a screen and housings, and side walls of the housings have inner surfaces that define the inner surface of a discharge path. Let communication hole be any through-hole that interconnects the defibrating chamber and the discharge path, and let discharge path-side opening edge be the opening edge, close to the discharge path, of the through-hole, then the screen has through-hole rows, each of which is formed by a plurality of communication holes arranged at an interval in a circumferential direction, and the through-hole row is provided at a position where the discharge path-side opening edge of the communication holes is overlapped with the inner surface as seen in a radial direction.

The present application is based on, and claims priority from JP Application Serial Number 2021-123136, filed Jul. 28, 2021, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a defibrating apparatus, and a fiber body manufacturing apparatus.

2. Related Art

JP-A-2020-158944 discloses a defibrating apparatus that discharges a defibrated material formed from a raw material through a discharge path extending along the outside of an annular wall which defines a defibrating chamber, and through a discharge pipe communicating with the discharge path, by rotating a rotational body stored in the defibrating chamber. In the defibrating apparatus, the discharge path and the defibrating chamber communicate with each other by a plurality of through-holes provided in the annular wall of the defibrating chamber. The defibrated material formed in the defibrating chamber passes through the through-holes by an air flow, and is discharged to the discharge path.

However, in the defibrating apparatus described in JP-A-2020-158944, a defibrated material discharged to the discharge path may stagnate on the inner surface of the discharge path.

SUMMARY

A defibrating apparatus includes: a rotational body rotatable around a center at an axis of a rotational shaft; a defibrating chamber that stores the rotational body which when rotated, causes a defibrated material to be formed from a raw material containing fibers; a discharge path that communicates with the defibrating chamber, and receives the defibrated material discharged from the defibrating chamber; a circular annular wall that is provided at an interval from the rotational body in a radial direction of the rotational body, and that defines the defibrating chamber; a housing that forms the discharge path; and a plurality of through-holes provided in the annular wall, the plurality of through-holes penetrating the annular wall in the radial direction. The discharge path has a width in an axial direction along the axis, and extends in a circumferential direction of the annular wall, the housing has a side wall extending in the circumferential direction, and the side wall has an inner surface that defines the discharge path, let a communication hole be any of the through-holes which interconnect the defibrating chamber and the discharge path, and let a discharge path-side opening edge be any of opening edges, close to the discharge path, of the through-holes, then the annular wall has a communication hole group which is formed by a plurality of communication holes, each of which is the communication hole, which are arranged at intervals in the circumferential direction, and the communication hole group is provided at a position where the discharge path-side opening edge of the communication hole is overlapped with the inner surface as seen in the radial direction.

A fiber body manufacturing apparatus includes: the defibrating apparatus described above; a web former that forms a web by accumulating the defibrated material discharged from the defibrating apparatus; and a fiber body former that forms a fiber body including fibers by binding the fibers contained in the web.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present disclosure will be described based on the embodiment below. In each of the drawings, the same members are labeled with the same symbol, and a redundant description is omitted. Note that in the present specification, “the same” refers to not only completely the same, but also the same in consideration of measurement error, the same in consideration of manufacturing variation in members, and the same in a range where functions are not impaired. Thus, for instance, “both sizes are the same” indicates that in consideration of measurement error, and manufacturing variation in members, the difference in both sizes is within ±10% of one of the sizes, more preferably, within ±5% of one of the sizes, and further more preferably, within ±3% of one of the sizes.

In addition, in each drawing, X, Y, Z represent three space axes perpendicular to each other. In the present specification, the directions along these axes are called X-axis direction, Y-axis direction and Z-axis direction. When a direction is specified, let “+” indicate the positive direction and “−” indicate the negative direction, and the symbols of positive and negative are both used for direction notation. A description is given where in the drawings, + direction indicates the direction of each arrow and − direction indicates the opposite direction of each arrow. The Z-axis direction indicates the gravity direction, the +Z direction indicates the vertically downward direction, and the −Z direction indicates the vertically upward direction. A description is given where X-Y plane denotes the plane including the X-axis, the Y-axis, X-Z plane denotes the plane including the X-axis, the Z-axis, and Y-Z plane denotes the plane including the Y-axis, the Z-axis. The X-Y plane is a horizontal plane. In addition, a description is given where X-axis, Y-axis, Z-axis are three space axes of X, Y, Z with their positive direction or negative direction not specified.

The configuration of a sheet manufacturing apparatus100according to Embodiment 1 will be described. The sheet manufacturing apparatus100fiberizes a raw material MA containing fibers, and recycles the material into a new sheet S. The sheet manufacturing apparatus100is an example of a fiber body manufacturing apparatus. In addition, the sheet S is an example of a fiber body.

As illustrated inFIG.1, the sheet manufacturing apparatus100includes a storage supplier10, a crusher12, a defibrating apparatus200, a selector40, a first web former45, a rotational body49, a mixer50, an accumulation section60, a second web former70, a transporter79, a sheet former80, and a cutter90.

The storage supplier10is an automatic injection apparatus that stores the raw material MA, and continuously injects the raw material MA into the crusher12. The raw material MA should include fibers, and is, for instance, used paper, waste paper, or pulp sheet.

The crusher12includes a crushing blade14that cuts the raw material MA supplied by the storage supplier10, and the crusher12cuts the raw material MA in the air into fragments measuring several square centimeters by the crushing blade14. For instance, a shredder can be used as the crusher12. The raw material MA cut by the crusher12is collected by a hopper9, and transported to a supply pipe20of the defibrating apparatus200through a pipe2.

Crushed fragments are transported from the crusher12to the defibrating apparatus200by air flow. In the defibrating apparatus200, the crushed fragments are transported from the supply pipe20to the later-described defibrating chamber210, and the crushed fragments are defibrated by rotation of a rotational body500stored in the defibrating chamber210.

A pipe3coupled to a discharge pipe30is provided with a suction unit35. The suction unit35includes a blower that can apply a negative pressure to the discharge pipe30by sucking the air close to the discharge pipe30in the pipe3. A defibrated material in the defibrating chamber210is discharged from the defibrating apparatus200through the later-described discharge path310and the discharge pipe30by air flow generated by the negative pressure applied to the discharge pipe30. The defibrated material discharged from the defibrating apparatus200is transferred to the selector40through the pipe3coupled to the discharge pipe30. The configuration of the defibrating apparatus200will be described below.

The selector40sorts the components contained in the defibrated material by size of fiber. The selector40has a drum unit41, and a storage43that stores the drum unit41. The drum unit41uses a sieve, for instance.

The defibrated material introduced into the drum unit41through an introduction port42is sorted by rotation of the drum unit41into a passing material which has passed through an opening of the drum unit41, and a remaining material which has not passed through the opening. A first sorted material, which is a passing material which has passed through the opening, moves down in the storage43to the first web former45.

In addition, a second sorted material, which is a remaining material which has not passed through the opening, is re-send from a discharge port44to the supply pipe20of the defibrating apparatus200through pipes8,2, the discharge port44communicating with the inside of the drum unit41.

The first web former45includes a mesh belt46, tension rollers47,47a, and a suction unit48. The mesh belt46is an endless-shaped belt, and is stretched over the multiple tension rollers47,47a. The mesh belt46circumferentially moves along a path formed by the tension rollers47,47a. Part of the path of the mesh belt46is planar under the drum unit41, and the mesh belt46forms a planar surface. The suction unit48corresponds to a suction mechanism.

A large number of openings are formed in the mesh belt46. Of the first sorted material moved down from the drum unit41located above the mesh belt46, those components larger than the openings of the mesh belt46are accumulated on the mesh belt46. In contrast, of the first sorted material, those components smaller than the openings of the mesh belt46pass through the openings.

The suction unit48includes a blower which is not illustrated, and sucks air from the opposite side to the drum unit41with respect to the mesh belt46. The components which have passed through the openings of the mesh belt46are sucked by the suction unit48. The air flow sucked by the suction unit48has an effect of accumulating components by attracting the first sorted material moved down from the drum unit41to the mesh belt46.

The components accumulated on the mesh belt46has a web shape, and form a first web Wb1. The basic configuration of the mesh belt46, the tension rollers47,47aand the suction unit48is the same as the configuration of a mesh belt72, a tension roller74and a suction mechanism76of the later-described second web former70.

The first web Wb1is transported to the rotational body49along with the movement of the mesh belt46.

The rotational body49includes a base49acoupled to a drive unit (not illustrated) such as a motor, and a projection49bprojecting from the base49a. Rotation of the base49ain direction D causes the projection49bto rotate around the base49a.

The rotational body49is located at the end, close to the tension roller47a, of the planar portion of the path of the mesh belt46. At the end, the path of the mesh belt46is bent downward, thus the first web Wb1transported by the mesh belt46projects from the mesh belt46, and comes into contact with the rotational body49. The first web Wb1is disintegrated due to collision of the projection49btherewith, and turns into a mass of small fibers. The mass is transported to the mixer50through a pipe7located below the rotational body49.

The mixer50mixes the first sorted material with an additive material. The mixer50has an additive material supply unit52that supplies an additive material, a pipe54for transporting the first sorted material and the additive material, and a mixing blower56.

The additive material supply unit52supplies an additive material to a pipe54, the additive material including fine powder or fine particles in an additive material cartridge52a.

The additive material supplied by the additive material supply unit52contains a resin to bind multiple fibers, in other words, a binding agent. The resin contained in the additive material is melted when being passed through the sheet former80, thereby binding multiple fibers.

The mixing blower56generates an air flow in the pipe54which couples the pipe7and the accumulation section60. In addition, the first sorted material transported from the pipe7to the pipe54, and the additive material supplied to the pipe54by the additive material supply unit52are mixed when being passed through the mixing blower56.

The accumulation section60moves down the fibers in a mixture to the second web former70, while disentangling and dispersing the fibers in the air.

The accumulation section60has a drum unit61, an introduction port62for introducing a mixture to the drum unit61, and a storage63that stores the drum unit61. The drum unit61is a cylindrical structure which is formed in the same manner as the drum unit41, for instance, and rotates by the power of a motor (not illustrated), and functions as a sieve in the same manner as the drum unit41.

The second web former70is disposed below the drum unit61. The second web former70includes, for instance, a mesh belt72, a tension rollers74, and a suction mechanism76. The second web former70is an example of a web former.

Of the mixture moved down from the drum unit61located above the mesh belt72, the components larger than the openings of the mesh belt72are accumulated on the mesh belt72. The components accumulated on the mesh belt72has a web shape, and form a second web Wb2.

In the transportation path of the mesh belt72, a humidity controller78is provided downstream of the accumulation section60. The amount of water contained in the second web Wb2is adjusted by the moisture supplied by the humidity controller78, thus the effect of reducing adsorption of fibers to the mesh belt72due to static electricity cab be expected.

The second web Wb2is removed from the mesh belt72by the transporter79, and transported to the sheet former80. The transporter79has, for instance, a mesh belt79a, a roller79b, and a suction mechanism79c. The suction mechanism79cincludes a blower which is not illustrated, and generates an upward air flow via the mesh belt79aby the suction force of the blower. The air flow causes the second web Wb2to be separated from the mesh belt72, and to be adsorbed to the mesh belt79a. The mesh belt79ais moved by the rotation of the roller79bto transport the second web Wb2to the sheet former80.

The mesh belt79acan be formed as an endless-shaped belt having openings in the same manner as the mesh belt46and the mesh belt72.

The sheet former80binds the fibers from the first sorted material contained in the second web Wb2and the resin contained in the additive material by applying heat to the second web Wb2.

The sheet former80includes a pressure unit82that pressurizes the second web Wb2, and a heater84that heats the second web Wb2pressurized by the pressure unit82. The pressure unit82pressurizes the second web Wb2with a predetermined nip pressure by a pair of calendar rollers85, and transports the second web Wb2to the heater84. The heater84catches the densified second web Wb2by a pair of heating rollers86to apply heat to the second web Wb2, and transports it to the cutter90. In the heater84, the resin contained in the second web Wb2is heated, and turned into a sheet S. The sheet former80is an example of a fiber body former.

The cutter90cuts the sheet S formed by the sheet former80. The cutter90has a first cutter92that cuts the sheet S in a direction crossing a transport direction F1of the sheet S indicated by a symbol F1inFIG.1, and a second cutter94that cuts the sheet S in a direction parallel to the transport direction F1. The cutter90cuts the length and the width of the sheet S with a predetermined size to form single sheets S. The sheet S cut by the cutter90is stored in the discharge section96.

Next, the configuration of the defibrating apparatus200will be described. The defibrating apparatus200is an apparatus that performs a process of disintegrating the raw material MA in a state of multiple fibers bonded to one or a small number of fibers. The defibrating apparatus200is a dry defibrating apparatus that performs a process of defibration in a gas such as atmosphere, air, and not in liquid.

As illustrated inFIGS.2to5, the defibrating apparatus200includes the rotational body500, the defibrating chamber210, the supply pipe20, the discharge path310, and the discharge pipe30. The defibrating apparatus200forms a defibrated material from the raw material MA supplied through the supply pipe20by rotating the rotational body500stored in the defibrating chamber210, around an axis AR of a rotational shaft501. The defibrating apparatus200includes a screen221, a fixing member211, and side walls212,213that define the defibrating chamber210; housings311,312,313that define the discharge path310; supporting units401,402that support the rotational body500; and a blocking member601. In the description below, the rotational direction in which the rotational shaft501rotates around the axis AR, and the radial direction of the rotational shaft501may be called a circumferential direction CR, and a radial direction RR, respectively.

The rotational body500has the rotational shaft501, a base502, rotary blades503, and rotary vanes504. The rotational body500is stored in the defibrating chamber210so that the axis AR of the rotational shaft501is along the Y-axis. Thus, the rotational shaft501extends in the Y-axis direction. The Y-axis direction is an example of an axial direction. In other words, the defibrating apparatus200is disposed in the sheet manufacturing apparatus100in a posture in which the axis AR is horizontal. The base502has a circular plate shape, and is inserted in the rotational shaft501and fixed. The rotary blades503are provided to project in a direction away from the base502in the radial direction RR. The rotary blades503have a plate-like projection shape. The multiple rotary blades503are formed at intervals in the circumferential direction CR.

The multiple rotary vanes504are provided on +Y direction side of the base502at intervals in the circumferential direction CR. As illustrated inFIG.5, in the embodiment, the rotary blades503and the base502are formed by stacking thin laminated plates in the Y-axis direction; however, the rotary blades503and the base502may be formed as a block in an integrated shape.

As illustrated inFIG.4,FIG.6, the fixing member211has a cylindrical shape. The fixing member211is located on the +Y direction side of the rotary blades503in the Y-axis direction.

As illustrated inFIG.4,FIG.10,FIG.12, the side wall212has a circular plate shape. The side wall212is located on the +Y direction side of the fixing member211. The side wall212defines the inner surface of the defibrating chamber210on the +Y direction side by being fixed to the fixing member211. The side wall212is provided with the supporting unit401, the supply pipe20, and a supply unit214.

The supporting unit401is located at the center of the side wall212. The supporting unit401is located on the +Y direction side of the rotary blades503of the rotational body500. The supporting unit401supports the rotational shaft501of the rotational body500so that the rotational body500is rotatable around the axis AR as the rotation center. The supporting unit401supports +Y direction side of the rotary blades503of the rotational shaft501of the rotational body500.

The rotational shaft501is rotationally driven by a drive mechanism which is not illustrated. In the embodiment, the drive mechanism is comprised of a belt and pulleys, power is transmitted from a rotary drive source (not illustrated) to the belt and the pulleys, and the rotational body500is rotated around the axis AR as the rotation center. In the embodiment, the rotational body500is rotated counterclockwise around the axis AR as the rotation center inFIG.11; however, the rotational body500may be rotated clockwise. Alternatively, inFIG.11, the rotational body500may be rotated in both clockwise and counterclockwise directions around the axis AR as the rotation center. In addition, the configuration in which the rotational shaft501is rotationally driven may not be the configuration based on a belt and pulleys.

The supply pipe20supplies the raw material MA containing fibers to the defibrating chamber210. As illustrated inFIG.4,FIG.6,FIG.12, the supply pipe20has a pipe shape. The supply pipe20is provided on the surface of the side wall212on +Y direction side. The supply pipe20is provided at a position in −Z direction from the axis AR of the rotational shaft501in the side wall212. The supply pipe20extends in the Y-axis direction. The supply unit214is a circular through-hole which penetrates the side wall212in the Y-axis direction. The supply unit214interconnects the supply pipe20and the defibrating chamber210. Thus, the supply unit214is opened at a position vertically upward, that is, −Z direction from the axis AR of the rotational shaft501in the side wall212. In other words, in the side wall212, the supply unit214is opened at a position further away from the later-described discharge section314than from the axis AR.

As illustrated inFIG.4,FIG.6,FIG.10, a side wall213has a circular plate shape. The side wall213is located on −Y direction side of the fixing member211. The side wall213is located on −Y direction side of the rotary blades503of the rotational body500. The side wall213is fixed to the fixing member211via the screen221, thereby defining the inner surface of the defibrating chamber210on −Y direction side. The side wall213is provided with the supporting units402that supports −Y direction side of the rotary blades503in the rotational shaft501of the rotational body500.

As illustrated inFIG.4,FIGS.6to9,FIGS.11to14, the screen221has a thin plate shape. The screen221is located between the fixing member211and the side wall213in the Y-axis direction. The screen221is fixed to the fixing member211, and the side wall213, thus formed in an annular shape. The screen221is provided at an interval from the rotary blades503in the radial direction RR.

The dimension of the screen221in the Y-axis direction, that is, the width dimension of the screen221is larger than the dimension of each rotary blade503in the Y-axis direction. In the Y-axis direction, the tip end of each rotary blade503is located within the width of the screen221. The screen221is fixed to the fixing member211and the side wall213, thereby defining the inner circumferential surface the defibrating chamber210in a cylindrical shape. The screen221defines a region of the inner circumferential surface the defibrating chamber210, the region being opposed to the tip end of each rotary blade503. The screen221is an example of an annular wall.

The screen221is comprised of a thin plate member made of metal, for instance. The screen221of the embodiment is fixed to the fixing member211and the side wall213so that multiple thin plate members are arranged in the circumferential direction CR, thereby being formed in an annular shape. For instance, stainless steel can be used as a metal material.

As illustrated inFIG.4,FIGS.9to14, the housings311,312,313are provided to surround the outside of the screen221in the circumferential direction CR. The housings311,312,313cover the outside of the screen221over the entire circumference in the circumferential direction CR, thereby forming the discharge path310. The housings311,312,313are fixed to the fixing member211and the side wall213with the screen221interposed with the fixing member211and with the side wall213. In this case, the side wall213can be called an example of a fixing member that fixes the screen221.

The housings311,312,313have an outer circumferential wall351, a side wall352, and a side wall353. The outer circumferential wall351is provided at an interval from the screen221by an interval W in the radial direction RR. The outer circumferential wall351has an annular shape. The interval W between the outer circumferential wall351and the screen221in the radial direction RR is the inner dimension of the discharge path310in the radial direction RR.

The outer circumferential wall351defines the inner circumferential surface of the discharge path310. The side wall352is located on +Y direction side of the outer circumferential wall351, and extends in the circumferential direction CR. The side wall352has an inner surface355, which defines the inner surface of the discharge path310on +Y direction side. The side wall353is located on −Y direction side of the side wall352, and extends in the circumferential direction CR. The side wall353has an inner surface356, which defines the inner surface of the discharge path310on −Y direction side. The interval D between the inner surface355and the inner surface356in the Y-axis direction is the width dimension of the discharge path310in the Y-axis direction. Three housings311,312,313are fixed to the fixing member211and the side wall213with the screen221interposed so as to be arranged in the circumferential direction CR, thus the discharge path310of the embodiment is formed in an annular shape.

As illustrated inFIG.4,FIGS.11to14, the discharge path310is provided outside of the screen221over the entire circumference in the circumferential direction CR. The discharge path310has a width in the Y-axis direction, and extends in the circumferential direction CR of the screen221. The discharge path310communicates with the defibrating chamber210through multiple through-holes222provided in the screen221. The defibrated material formed in the defibrating chamber210is discharged to the discharge path310through the multiple through-holes222. Note that the discharge path310may be formed by one housing member.

The outer circumferential wall351of the housing311is provided with the discharge pipe30and the discharge section314. The discharge pipe30is provided on +Z direction side of the outer circumferential wall351of the housing311. The discharge pipe30is located on +Z direction side, which is vertically downward from the axis AR of the rotational shaft501. Thus, the discharge pipe30is provided at the lowest position of the outer circumferential wall351. The discharge pipe30has a pipe shape. The discharge pipe30extends from the outer circumferential wall351in +Z direction.

The discharge section314is a through-hole which penetrates the outer circumferential wall351in the Z-axis direction. The discharge section314has an approximately square shape as seen in the Z-axis direction. An opening edge315is the edge of an opening, close to the discharge path310, of the discharge section314. The dimension of the opening edge315in the Y-axis direction is the same as the inner dimension of the discharge path310in the Y-axis direction. The dimension of the opening edge315in the X-axis direction is set to 40 mm to 50 mm. The dimension of the discharge section314in the Y-axis direction is the same as the inner dimension of the discharge path310in the Y-axis direction.

The discharge section314interconnects the discharge path310and the discharge pipe30. The discharge section314is provided in the outer circumferential wall351, and is opened toward the screen221. Thus, in the outer circumferential wall351, the discharge section314is provided at a position in +Z direction, which is vertically downward from the axis AR of the rotational shaft501. In other words, the discharge section314is provided at the lowest position of the outer circumferential wall351.

In the embodiment, the interval D between the side wall352and the side wall353is the same over the entire circumference of the screen221. The interval D is set to a predetermined dimension from 40 mm to 50 mm, for instance. In contrast, the interval W between the outer circumferential wall351and the screen221is greater in an opposing region opposed to the discharge section314than in a region further away from the opposing region in the circumferential direction CR of the screen221.

For instance, as illustrated inFIG.14, in the discharge path310, let width W1be the width W of the region located in −Z direction from the axis AR, let width W2be the width W of the region located in +X direction from the axis AR, let width W3be the width W of the region located in +Z direction from the axis AR, and let width W4be the width W of the region located in −X direction from the axis AR. Then, the width W1is smaller than the width W3. In addition, the width W2and the width W4are smaller than the width W3. In addition, the width W1is smaller than the width W2and the width W4. Note that in the embodiment, the width W2and the width W4are the same.

In the embodiment, the width W gradually decreases as the distance from the discharge section314increases in the circumferential direction CR of the screen221. The interval D between the side wall352and the side wall353is the same over the entire circumference of the screen221. Therefore, the flow path cross-sectional area of the discharge path310gradually decreases as the distance from the discharge section314increases in the circumferential direction CR of the screen221. In the embodiment, for instance, the width W1is set to 5 mm, the width W2and the width W4are set to 10 mm, and the width W3is set to 15 mm.

As illustrated inFIG.8, in the screen221, the multiple through-holes222penetrating the screen221are formed in the radial direction RR which is the thickness direction. In the embodiment, the multiple through-holes222have the same shape. The through-holes222of the embodiment are circular holes. The hole diameter of the through-holes222is set to a size which allows the material defibrated to a desired extent to pass through. The screen221may be produced by forming through-holes222in a thin plate member by a punching process, an etching process, a cutting process or the like. Note that the screen221may be comprised of one thin plate member.

As illustrated inFIG.7,FIG.8,FIG.11,FIG.16,FIG.17, the multiple through-holes222are provided so as to be distributed in the circumferential direction CR of the screen221. To illustrate the arrangement of the multiple through-holes222,FIG.17shows a development view in which the annular screen221as seen from the discharge path310is developed into a flat plate shape. Thus,FIG.17corresponds to a state of the annular screen221, in which it is seen in the radial direction RR. In addition, the Y-axis direction, and the circumferential direction CR illustrated inFIG.17correspond to those when the screen221is fixed to the fixing member211and the side wall213to define the defibrating chamber210. InFIG.17, chain double-dashed lines indicate the positions of the inner surfaces355,356when the discharge path310is formed by covering the outside of the screen221with the housings311,312,313. The same applies toFIG.18toFIG.20which show the later-described other embodiments of the screen221.

As illustrated inFIG.17, in the screen221, multiple through-hole rows223are provided with the same center-to-center pitch Py in the Y-axis direction, and each through-hole row223includes the through-holes222with a hole diameter φWh arranged at interval Gh in the circumferential direction CR. In other words, in the screen221, multiple through-hole rows223are provided at the same interval (Py−Wh) in the Y-axis direction, and each through-hole row223includes the through-holes222with the hole diameter φWh arranged at the interval Gh in the circumferential direction CR.

In addition, in the screen221, a pair of through-hole rows224,225are provided corresponding to the positions of the inner surfaces355,356. In the embodiment, the through-hole rows224,225are formed by arranging the through-holes222with the hole diameter φWh at the interval Gh in the circumferential direction CR. The through-hole rows224,225are provided with the same center-to-center pitch Py between through-hole rows223adjacent in the Y-axis direction. As a result, the center-to-center pitch Iy between the through-hole row224and the through-hole row225is an integral multiple of the center-to-center pitch Py. Thus, the through-hole rows224,225are included in multiple through-hole rows223.

In the embodiment, the through-holes222are displaced in the circumferential direction CR with respect to other through-holes222included in the adjacent through-hole rows223in the Y-axis direction. In other words, multiple through-holes222are provided in the screen221in a so-called staggered pattern. In the embodiment, the through-holes222are displaced in the circumferential direction CR by half (Gh+Wh) as the center-to-center pitch with respect to other through-holes222included in the adjacent through-hole rows223in the Y-axis direction.

The hole diameter Wh of each through-hole222is preferably φ0.3 mm or more and φ2.0 mm or less. The interval Gh between adjacent through-holes222is preferably the same dimension as the thickness of the screen221to twice the hole diameter Wh of each through-hole222, and is more preferably half the hole diameter Wh of each through-hole222to twice the hole diameter Wh. The interval Gh between adjacent through-holes222is the dimension of the remaining part of the screen221, which is the shortest distance between the opening edges of adjacent through-holes222.

In the embodiment, the hole diameter φWh, and the center-to-center pitch Py between adjacent through-hole rows223are set so that the interval between each through-hole222and six other through-holes222which surround the through-hole222is equal to the interval Gh between the through-hole222and another adjacent through-hole222in the circumferential direction CR. For instance, the hole diameter Wh of each through-hole222is set to φ0.6 mm, and the center-to-center pitch Py between adjacent through-hole rows223in the Y-axis direction is set to φ1.5 mm. In this case, the interval Gh between adjacent through-holes222is Gh=2/(3{circumflex over ( )}0.5)*Py−Wh=1.1 mm. Alternatively, the interval Gh between adjacent through-holes222is Gh=(3{circumflex over ( )}0.5)*Py−Wh=2.0 mm. When through-hole rows223including the through-hole rows224,225are arranged in 29 rows in the Y-axis direction, the center-to-center pitch Iy between the through-hole row224and the through-hole row225is 42 mm.

Let discharge path-side opening edge228be the opening edge, close to the discharge path310, of each through-hole222. At this point, the through-hole row224is provided at a position where the discharge path-side opening edge228of the through-holes222included in the through-hole row224is overlapped with the inner surface355as seen in the radial direction RR. In addition, the through-hole row225is provided at a position where the discharge path-side opening edge228of the through-holes222included in the through-hole row225is overlapped with the inner surface356as seen in the radial direction RR. As illustrated inFIG.16, the fixing member211is located on +Y direction side with respect to the inner surface355, and the through-hole row224in the Y-axis direction. In addition, the side wall213is located on −Y direction side with respect to the inner surface356, and the through-hole row225in the Y-axis direction.

Thus, let a communication hole Ch be a through-hole222which interconnects the defibrating chamber210and the discharge path310, then the through-hole row224is provided at a position where the discharge path-side opening edge228of the communication holes Ch included in the through-hole row224is overlapped with the inner surface355as seen in the radial direction RR. In addition, the through-hole row225is provided at a position where the discharge path-side opening edge228of the communication holes Ch included in the through-hole row225is overlapped with the inner surface356as seen in the radial direction RR. The through-hole rows224,225are an example of a pair of communication hole groups. In addition, the through-hole row224is an example of one of the communication hole groups, and the through-hole row225is an example of the other of the communication hole groups.

FIG.17shows the case where in the through-hole row224, +Y direction side of the discharge path-side opening edge228of the through-hole222is in contact with the inner surface355, and in the through-hole row225, −Y direction side of the discharge path-side opening edge228of the through-holes222is in contact with the inner surface356. In this case, in the through-holes222of the through-hole rows224,225, the ratio of the opening area opened in the discharge path310to the opening area opened, close to the discharge path310, of the through-holes222is 100%. When manufacturing variation in components such as the screen221, the housings311,312,313, and position variation in the housings311,312,313with respect to the screen221are taken into consideration, the interval D between the inner surface355and the inner surface356is set to a dimension which satisfies Iy−Wh<D≤Iy+Wh.

The ratio of the opening area opened in the discharge path310to the opening area opened, close to the discharge path310, of the through-holes222is preferably 50% or higher, and more preferably 80% or higher. In the embodiment, as illustrated inFIG.16, the housings311,312,313are fixed to the fixing member211and the side wall213with the screen221covered by the housings311,312,313. The housings311,312,313are fixed to the fixing member211and the side wall213with the screen221interposed with the fixing member211and with the side wall213. In addition, the housings311,312,313are fixed to the fixing member211and the side wall213by inserting fixing screws (not illustrated) into threaded holes361provided in the housings311,312,313, and tightening the fixing screws.

For instance, when the housing312is fixed to the fixing member211and the side wall213, first, the housing312is arranged at a position for covering the screen221. At this point, the screen221is fixed to the fixing member211and the side wall213. The dimension of the screen221in the Y-axis direction, that is, the width dimension of the screen221is larger than the interval D between the inner surface355and the inner surface356. Thus, as indicated by the white arrow inFIG.16, the position of the housing312is movable in the Y-axis direction with respect to the screen221with the screen221covered by the housing312.

The position of the housing312is movable in the Y-axis direction with respect to the screen221with the screen221interposed with the fixing member211and with the side wall213. Thus, the position of the housing312is adjustable at a position where the inner surface355is overlapped with the discharge path-side opening edge228of the through-hole row224provided in the screen221, and the inner surface356is overlapped with the discharge path-side opening edge228of the through-hole row225.

The hole size of the threaded hole361is set to be greater than the diameter of the fixing screw so that the housing312can be tightened and fixed to the fixing member211and the side wall213by a fixing screw with the position of the housing312adjusted with respect to the screen221. Thus, in the embodiment, the housing312can be fixed to the fixing member211and the side wall213with the position of the housing312adjusted with respect to the screen221.

In the embodiment, it may be stated that multiple through-hole rows each including through-holes222arranged in the Y-axis direction are provided over the entire circumference of the screen221at the same interval Gh in the circumferential direction CR. However, multiple through-hole rows each including through-holes222arranged in the Y-axis direction may be provided over the entire circumference of the screen221at some different intervals in the circumferential direction CR. Alternatively, through-hole groups each including through-holes222arranged in the Y-axis direction and the circumferential direction CR may be provided over the entire circumference of the screen221at the same intervals in the circumferential direction CR. In the embodiment, the same number of through-holes222are arranged in the Y-axis direction to form each through-hole row; however, through-hole rows may have different numbers of through-holes to form each through-hole row.

When the through-holes222are formed in a thin plate member by an etching process, for instance, SUS430, SUS304, and SUS316L may be used as the material for the thin plate member. Alternatively, the screen221may be a mesh formed by weaving wires. In this case, the pores of the mesh correspond to the through-holes222.

As illustrated inFIG.4,FIGS.11to14, the blocking member601is provided on the outer circumferential surface, close to the discharge path310, of the screen221. The blocking member601is provided in an opposing region, of the screen221, opposed to the discharge section314. The blocking member601is located in +Z direction from the axis AR. The blocking member601blocks the openings, close to the discharge path310, of the through-holes222by covering the outer circumferential surface, close to the discharge path310, of the screen221. The blocking member601blocks the through-holes222provided in a region which is close to the discharge section314in the screen221. Note that the blocking member601may be provided on the inner circumferential surface, close to the defibrating chamber210, of the screen221. In this case, the blocking member601blocks the openings, close to the defibrating chamber210, of the through-holes222by covering the inner circumferential surface, close to the defibrating chamber210, of the screen221.

In the embodiment, the dimension of the blocking member601in the Y-axis direction is the same as the dimension of the discharge path310in the Y-axis direction. The dimension of the blocking member601in the X-axis direction is greater than the dimension of the opening edge315in the discharge section314in the X-axis direction.

As illustrated inFIG.14, the angle formed between the line segment connecting the axis AR and the end of the blocking member601in +X direction, and the line segment connecting the axis AR and the end of the opening edge315in +X direction is θ. In addition, the angle formed between the line segment connecting the axis AR and the end of the blocking member601in −X direction, and the line segment connecting the axis AR and the end of the opening edge315in −X direction is θ. Thus, the position of the end of the blocking member601in +X direction is located away in +X direction by the angle θ relative to the position of the end of the opening edge315in +X direction. In addition, the position of the end of the blocking member601in −X direction is located away in −X direction by the angle θ relative to the position of the end of the opening edge315in −X direction. In the embodiment, the angle θ is set to 5° to 15°, for instance.

In the screen221, the through-holes222provided in the region with the outer circumferential surface covered by the blocking member601do not interconnect the defibrating chamber210and the discharge path310. In other words, in the screen221, the region with the outer circumferential surface covered by the blocking member601is not provided with any communication hole Ch. In the embodiment, the region between the center of the discharge section314and the rotational shaft501of the screen221in the Z-axis direction is not provided with any communication hole Ch.

Let projection line segment be the line segment which is perpendicular to the axis AR and connects the axis AR and the center of the discharge section314, and let projection direction be the direction along the projection line segment. In the embodiment, when the opening edge315of the discharge section314is projected onto the screen221, the region surrounded by the opening edge315projected onto the screen221is not provided with any communication hole Ch. In the embodiment, the above-mentioned projection direction is a direction along the Z-axis direction. The region surrounded by the opening edge315projected onto the screen221is an example of an opposing region, in the screen221, opposed to the discharge section314.

Let virtual line segment LD be the line segment which is perpendicular to the axis AR and connects the axis AR and the opening edge315of the discharge section314, and let region RD be the region surrounded by the virtual line segment LD in the screen221, then the region RD is not provided with any communication hole Ch in the embodiment. The region RD is an example of an opposing region, in the screen221, opposed to the discharge section314.

As a result, let region ERD (not illustrated) be the region other than the region RD in the screen221, then the number of communication holes Ch provided per unit area in the region RD is less than the number in the region ERD. In the screen221, let region RN be the region with the interval W1which is the smallest interval W between the outer circumferential wall351and the screen221, and let region ERN (not illustrated) be the region other than the region RN, then the number of communication holes Ch provided per unit area in the region RN is greater than the number in the region ERN.

The number of communication holes Ch provided per unit area in the region RN is greater than the number in the region RD. In the embodiment, the region RN, and the region with the interval W1which is the smallest interval W in the discharge path310are located in −Z direction which is vertically upward from the axis AR. Thus, the region RN is an example of a region of the screen221, furthest away from the discharge section314in the circumferential direction CR.

In the embodiment, the outer circumferential surface of the screen221is covered by the blocking member601, thus, the region not provided with any through-hole222is formed in the screen221, the through-holes222interconnecting the defibrating chamber210and the discharge path310. However, in the screen221of the embodiment, any through-hole222is not formed in the region with the outer circumferential surface covered by the blocking member601, thus in the screen221, the region may be formed, which is not provided with any through-hole222which interconnects the defibrating chamber210and the discharge path310.

Next, the operation of the defibrating apparatus200will be described. The defibrating apparatus200guides the raw material MA supplied to the defibrating chamber210to the gap between the rotary blades503of the rotating rotational body500and the screen221by air flow, and performs a dry defibration process on the raw material MA.

In the embodiment, as illustrated inFIG.4, the raw material MA injected from the supply pipe20of the defibrating apparatus200is introduced to the defibrating chamber210through the supply unit214. In the defibrating chamber210, the rotational shaft501is rotationally driven, thereby causing the rotational body500to rotate. In addition, a negative pressure due to the suction unit35is applied to the discharge path310through the discharge pipe30. Therefore, in the defibrating chamber210, the discharge path310and the discharge pipe30, an air flow is generated as indicated by a dashed line arrow inFIG.4.

This air flow sends the raw material MA to the gap between the tip ends of the rotary blades503and the screen221. The raw material MA sent to the gap flies by receiving a centrifugal force from the rotational body500, collides with the screen221, and is disintegrated and defibrated. That is, in the defibrating chamber210, the raw material MA is defibrated to produce a defibrated material.

The defibrated material generated in the defibrating chamber210passes through the through-holes222of the screen221due to air flow, and flows into the discharge path310. The defibrated material flowed into the discharge path310is moved to the discharge pipe30by an air flow through the discharge section314, and discharged to the pipe3coupled to the discharge pipe30. The air flow causing the defibrated material to move is generated by the pressure difference between the negative pressure applied to the discharge pipe30by the suction unit35, and the pressure in the discharge section314, the discharge path310, and the defibrating chamber210, which are upstream of the discharge pipe30. For instance, the air flow which passes through the through-holes222of the screen221is generated by the pressure difference between the negative pressure applied to the discharge path310from the suction unit35and the pressure in the defibrating chamber210.

In the vicinity of the inner surface of the discharge path310defined by the inner surfaces355,356of the housings311,312,313in the discharge path310, it is more difficult to ensure the air flow than in the vicinity of the center of the discharge path310in the Y-axis direction. Therefore, the defibrated material discharged from the defibrating chamber210to the discharge path310may stagnate in the vicinity of the inner surface of the discharge path310.

In the embodiment, in the screen221, the through-hole row224is provided at a position where the discharge path-side opening edge228of the communication holes Ch included in the through-hole row224is overlapped with the inner surface355as seen in the radial direction RR. Thus, an air flow along the inner surface355is likely to be ensured, and the defibrated material can be prevented from stagnating in the vicinity of the inner surface355. In addition, the through-hole row225is provided at a position where the discharge path-side opening edge228of the communication holes Ch included in the through-hole row225is overlapped with the inner surface356as seen in the radial direction RR. Thus, an air flow along the inner surface356is likely to be ensured, and the defibrated material can be prevented from stagnating in the vicinity of the inner surface356.

In the discharge path310, a negative pressure due to the suction unit35is likely to be applied to a region close to the discharge section314. Thus, in the through-holes222provided in a region close to the discharge section314, the flow rate of the air passing from the defibrating chamber210to the discharge path310is likely to increase. Furthermore, in the through-holes222provided in the region close to the discharge section314, the flow speed of the air passing from the defibrating chamber210to the discharge path310is likely to increase. In this case, in the through-holes222provided in the region close to the discharge section314, an incompletely defibrated material which has not been sufficiently defibrated may be discharged to the discharge path310. Also, the defibrated material may be clogged in some through-holes222.

In the through-holes222provided in a region close to the discharge section314, when the flow rate of the air passing from the defibrating chamber210to the discharge path310increases, a negative pressure due to the suction unit35is unlikely to be applied to a region away from the discharge section314. Thus, in the through-holes222provided in a region away from the discharge section314, the flow speed of the air passing from the defibrating chamber210to the discharge path310is likely to decrease. In a region where the flow speed of the air passing through the through-holes222of the screen221is low, the defibrated material is unlikely to pass through the through-holes222. As a result, an excessively defibrated material increases in the amount, which has stagnated for a long time in the defibrating chamber210and been defibrated to an excessive extent.

In the embodiment, for instance, as illustrated inFIG.15, let downstream-side discharge path310D close to the discharge section314be a region of the discharge path310, including the discharge section314, and let upstream-side discharge310U away from the discharge section314be the region other than the downstream-side discharge path. Let downstream-side screen221D be the region of the screen221, constituting the downstream-side discharge path310D, and let upstream-side screen221U be the region constituting the upstream-side discharge310U. Let communication hole Ch be each through-hole222which interconnects the defibrating chamber210and the discharge path310, the number of communication holes Ch provided per unit area in the downstream-side screen221D is less than the number in the upstream-side screen221U.

In other words, when the downstream-side screen221D and the upstream-side screen221U having the same area are compared with each other, the screen221is provided with communication holes Ch so that air is more unlikely to pass through in the downstream-side screen221D than in the upstream-side screen221U. Note that in the embodiment, when the blocking member601is provided, the downstream-side discharge path310D is a region including the region RD, the blocking member601, and the discharge section314, whereas the upstream-side discharge310U is a region including the region RN, and not including the blocking member601, and the discharge section314. The downstream-side screen221D is an example of a downstream-side annular wall, and the upstream-side screen221U is an example of an upstream-side annular wall.

Thus, as compared to when the number of communication holes Ch provided per unit area is the same over the entire circumference of the screen221, it is possible to reduce the flow rate of the air passing through the through-holes222of the downstream-side screen221D from the defibrating chamber210to the discharge path310. In addition, a negative pressure due to the suction unit35is likely to be applied to the upstream-side discharge310U. Furthermore, it is likely to increase the flow speed of the air passing through the through-holes222of the upstream-side screen221U from the defibrating chamber210to the discharge path310. As a result, it is possible to reduce discharge of an incompletely defibrated material which has not been sufficiently defibrated, from the through-holes222of the downstream-side screen221D to the discharge path310. In addition, it is possible to reduce an excessively defibrated material which has been defibrated to an excessive extent. Also, an air flow along the inner surface of the upstream-side discharge310U is likely to be ensured, and the defibrated material discharged to the upstream-side discharge310U can be prevented from stagnating in the vicinity of the inner surfaces355,356.

In addition, the pressure difference between the pressure in the downstream-side discharge path310D and the pressure in the upstream-side discharge310U is likely to reduce. The speed difference between the flow speed of the air passing through the through-holes222of the downstream-side screen221D and the flow speed of the air passing through the through-holes222of the upstream-side screen221U is likely to reduce. Thus, variation in defibration degree of the defibrated material discharged to the discharge path310can be reduced. In addition, the defibrated material discharged to the upstream-side discharge310U can be prevented from stagnating in the vicinity of the inner surfaces355,356.

In the embodiment, as illustrated inFIG.11, the discharge path310is provided to cover the outside of the screen221over the entire circumference. The discharge section314is provided in the outer circumferential wall351of the housings311,312,313forming the discharge path310, and is opened to the screen221. Thus, in the discharge path310, a negative pressure due to the suction unit35is likely to be applied to the side away upstream from the discharge section314. Therefore, in the screen221, an excessively defibrated material can be prevented from being discharged to a region away from the discharge section314, and variation in defibration degree of the defibrated material discharged to the discharge path310can be reduced.

As illustrated by a dashed arrow inFIG.11, in the discharge path310, a clockwise air flow toward the discharge section314can be generated in the region on +X direction side of the axis AR, and a counterclockwise air flow toward the discharge section314can be generated in the region on −X direction side of the axis AR. At this point, in the discharge path310, a clockwise air flow toward the discharge section314and a counterclockwise air flow toward the discharge section314can be generated in the region furthest away from the discharge section314and located in −Z direction which is vertically upward from the axis AR.

As described above, the following effects can be obtained by the defibrating apparatus200and the sheet manufacturing apparatus100according to Embodiment 1.

The defibrating apparatus200includes: a rotational body500rotatable around a center at an axis AR of a rotational shaft501; a defibrating chamber210that stores the rotational body500, which when rotated, generates a defibrated material from a material MA containing fibers; a discharge path310that communicates with the defibrating chamber210, and receives the defibrated material discharged from the defibrating chamber210; a circular annular screen221that is provided at an interval from the rotational body500in a radial direction RR of the rotational body500, and that defines the defibrating chamber210; housings311,312,313that form the discharge path310; and a plurality of through-holes222which are provided in the screen221, and penetrate the screen221in the radial direction RR. The discharge path310has a width in the Y-axis direction, and extends in the circumferential direction CR of the screen221. The housings311,312,313have the side walls352,353extending in the circumferential direction CR, and the side walls352,353have the inner surfaces355,356that define the discharge path310. Let communication hole Ch be each through-hole222that interconnects the defibrating chamber210and the discharge path310, and let discharge path-side opening edge228be the opening edge, close to the discharge path310, of the through-hole222, then the screen221has through-hole rows224,225, each of which is formed by a plurality of communication holes Ch arranged at interval Gh in a circumferential direction CR, and the through-hole row224is provided at a position where the discharge path-side opening edge228of the communication holes Ch is overlapped with the inner surface355as seen in the radial direction RR. Thus, an air flow along the inner surface355is likely to be ensured, and the defibrated material can be prevented from stagnating in the vicinity of the inner surface355.

The housings311,312,313have a pair of side walls352,353provided at an interval D in the Y-axis direction, and the side walls352,353have inner surfaces355,356. The screen221has a pair of through-hole rows224,225, one through-hole row224is provided at a position where the discharge path-side opening edge228of the communication holes Ch is overlapped with one inner surface355as seen in the radial direction RR, and the other through-hole row225is provided at a position where the discharge path-side opening edge228of the communication holes Ch is overlapped with the other inner surface356as seen in the radial direction RR. Thus, an air flow along the inner surfaces355,356is likely to be ensured, and the defibrated material can be prevented from stagnating in the vicinity of the inner surfaces355,356.

In the communication holes Ch of the through-hole rows224,225, the ratio of the opening area opened in the discharge path310to the opening area opened, close to the discharge path310, in the communication holes Ch is 50% or more. Thus, an air flow along the inner surfaces355,356is further likely to be ensured, and the defibrated material can be prevented from stagnating in the vicinity of the inner surfaces355,356.

The screen221has a plurality of through-hole rows223at interval (Py−Wh) in the Y-axis direction, and each through-hole rows223includes the through-holes222arranged at interval Gh in the circumferential direction CR, the plurality of through-hole rows223includes a pair of through-hole rows224,225, and the through-holes222are displaced in the circumferential direction CR with respect to other through-holes222included in the adjacent through-hole rows223in the Y-axis direction. The opening ratio is defined by the ratio of the total of opening areas of the through-holes222provided in the screen221to the area of the screen221constituting the discharge path310. For instance, as compared to when the through-holes222are arranged at the same position in the circumferential direction CR as other through-holes222included in adjacent through-hole rows223, the above-described configuration can increase the opening rate, while ensuring the intervals between the through-holes222. Thus, in the defibrating chamber210, the through-holes222of the screen221, and the discharge path310, an air flow for discharging the defibrated material downstream of the discharge path310is likely to be ensured, and the defibrated material can be prevented from stagnating in the discharge path310including the vicinity of the inner surfaces355,356.

The intervals Gh between each through-hole222and other through-holes222that surround the through-hole222are the same. This can further increase the opening rate, while ensuring the intervals between the through-holes222.

The dimension of the screen221in the Y-axis direction is greater than the dimension of the width of the discharge path310, and the housings311,312,313form the discharge path310by covering the outside of the screen221. Thus, it is easy to create a configuration which allows the positions of the housings311,312,313to be adjusted with respect to the screen221in the Y-axis direction.

A fixing member211that fixes the screen221is further provided, and the housings311,312,313are fixed to the fixing member211and the side wall213with the screen221interposed with the fixing member211and with the side wall213. Thus, it is easy to create a configuration which allows the housings311,312,313to be fixed to the fixing member211and the side wall213with the positions of the housings311,312,313adjusted with respect to the screen221.

The defibrating apparatus200further includes: a discharge pipe30that receives a negative pressure to discharge the defibrated material through the discharge path310; and a discharge section314that interconnects the discharge path310and the discharge pipe30. The housings311,312,313form the discharge path310in an annular shape by surrounding the outside of the screen221in the circumferential direction CR, and have an outer circumferential wall351provided at an interval from the screen221in the radial direction RR. The discharge section314is provided in the outer circumferential wall351, and opened toward the screen221. Thus, also when the discharge path310is provided on the outside of the screen221over the entire circumference, the discharge section314is provided so as to be opened toward the screen221, thus in the discharge path310, a negative pressure due to the suction unit35is likely to be applied to the side away upstream from the discharge section314. Thus, in the defibrating chamber210, the through-holes222of the screen221, and the discharge path310, an air flow for discharging the defibrated material downstream of the discharge path310can be ensured, and the defibrated material can be prevented from stagnating.

The sheet manufacturing apparatus100includes: the defibrating apparatus200; the second web former70that forms the second web Wb2by accumulating the defibrated material discharged from the defibrating apparatus200; and the sheet former80that forms the sheet S containing fibers by binding the fibers contained in the second web Wb2. Thus, the sheet manufacturing apparatus100can form the sheet S from the defibrated material generated by the defibrating apparatus200.

The defibrating apparatus200and the sheet manufacturing apparatus100according to the embodiment of the present disclosure are based on the configuration described above; however, it is obviously possible to make partial change or omission on the configuration in a range not departing from the spirit of the present disclosure. In addition, the embodiment and other embodiments described below can be implemented in a combination within a technically consistent range. The other embodiments will be described below.

In the embodiment, the pair of through-hole rows224,225may not be provided over the entire circumference of the screen221. For instance, the pair of through-hole rows224,225may be provided in the region RN of the screen221, and may not be provided in the region ERN. Accordingly, the number of communication holes Ch provided per unit area in the region RN may be made greater than the number in the region ERN. Alternatively, for instance, the pair of through-hole rows224,225may be provided in the upstream-side screen221U, and may not be provided in the downstream-side screen221D. Accordingly, the number of communication holes Ch provided per unit area in the upstream-side screen221U may be made greater than the number in the downstream-side screen221D.

In the embodiment, the screen221does not need to have the pair of through-hole rows224,225. For instance, when the defibrating apparatus200is disposed in the sheet manufacturing apparatus100in a posture in which the axis AR is along the vertical direction, and the side wall213is located upward of the fixing member211, the defibrated material is unlikely to stagnate in the vicinity of the inner surface356of the discharge path310. In this case, the through-hole row225as a communication hole group does not need to be provided. In other words, the screen221has the through-hole row224as a communication hole group.

In the embodiment, the interval Gh between adjacent through-holes222may be smaller than the hole diameter Wh of the through-holes222. For instance, as illustrated inFIG.18, the through-holes222may be provided in the screen221to be displaced in the circumferential direction CR by half (Gh+Wh) as the center-to-center pitch with respect to other through-holes222included in adjacent through-hole row224in the Y-axis direction. In this case, at least part of the discharge path-side opening edge228of the through-holes222is overlapped in position with the discharge path-side opening edge228of other through-holes222that surround the through-holes222in one of the circumferential direction CR and the Y-axis direction. Accordingly, the opening rate can be increased relative to the opening rate in the embodiment while ensuring the interval between the through-holes222. Alternatively, +Y direction side of the through-hole row224may be provided with a through-hole row226in which the discharge path-side opening edge228of the through-holes222is provided at a position overlapped with the inner surface355as seen in the radial direction RR. Alternatively, −Y direction side of the through-hole row225may be provided with a through-hole row227in which the discharge path-side opening edge228of the through-holes222is provided at a position overlapped with the inner surface356as seen in the radial direction RR. In this case, the through-hole row226and the through-hole row227are included in a plurality of through-hole rows224. In this case, the through-hole rows224,226are an example of one of the communication hole groups, and the through-hole rows225,227are an example of the other of the communication hole groups.

In the embodiment, the center-to-center pitch between the through-hole rows may not be the same. For instance, as illustrated inFIG.19, +Y direction side of the through-hole row224may be provided with the through-hole row226in which the discharge path-side opening edge228of the through-holes222is provided at a position overlapped with the inner surface355as seen in the radial direction RR. Alternatively, −Y direction side of the through-hole row225may be provided with the through-hole row227in which the discharge path-side opening edge228of the through-holes222is provided at a position overlapped with the inner surface356as seen in the radial direction RR. In this case, the center-to-center pitch Psy between the through-hole row224and the through-hole row226and between the through-hole row225and the through-hole row227is smaller than the center-to-center pitch Py between through-hole rows223. In this case, the through-hole rows224,226are an example of one of the communication hole groups, and the through-hole rows225,227are an example of the other of the communication hole groups.

In the embodiment, the opening shape of each through-hole222does not need to be circular. For instance, the opening shape may be oval such as an ellipse and a long circle, and may be polygonal such as a triangle and a quadrilateral. For instance, as illustrated inFIG.20, the plurality of through-holes222provided in the screen221may include through-hole222in different shapes. Note that inFIG.20, the through-holes222included in the through-hole rows224,225as communication hole groups have an oval shape with a width of Wh in the circumferential direction CR and a width of 2 Wh in the Y-axis direction. In this case, the center-to-center pitch Iy between the through-hole row224and the through-hole row225may be the same as the interval D between the side wall352and the side wall353. In this case, the through-hole row224is an example of one of the communication hole groups, and the through-hole row225is an example of the other of the communication hole groups. Note that the through-holes222included in the through-hole rows224,225illustrated inFIG.20may have an opening area smaller than that of the through-holes222included in the through-hole row223. In this case, for instance, the through-holes222included in the through-hole rows224,225may have an oval shape with a width of half Wh in the circumferential direction CR and a width of Wh in the Y-axis direction.

In the embodiment, the through-holes222may not be displaced in the circumferential direction CR with respect to other through-holes222included in adjacent through-hole row224in the Y-axis direction. In other words, a plurality of through-holes222may not be provided in the screen221in a staggered pattern. For instance, as illustrated inFIG.20, the through-holes222may be provided in the screen221in a so-called lattice pattern, in which the through-holes222are disposed at the same position as the other through-holes222included in adjacent through-hole row223in the circumferential direction CR.

In the embodiment, when one through-hole row224is provided at a position where the discharge path-side opening edge228of the communication holes Ch is overlapped with one inner surface355as seen in the radial direction RR, and the other through-hole row225is provided at a position where the discharge path-side opening edge228of the communication holes Ch is overlapped with the other inner surface356as seen in the radial direction RR, the positions of the housings311,312,313may not be movable with respect to the screen221in the Y-axis direction with the screen221covered by the housings311,312,313.

In the embodiment, the plurality of through-holes222have the same shape, and the screen221may be provided with the through-holes222so that the number of communication holes Ch provided per unit area in the screen221gradually increases as the distance from the discharge section314increases in the circumferential direction CR. In this case, for instance, through-hole rows each including the same number of through-holes222arranged in the Y-axis direction may be provided in the screen221so that the interval between through-hole rows decreases as the distance from the discharge section314increases in the circumferential direction CR. For instance, through-hole rows each including through-holes222arranged in the Y-axis direction may be provided in the screen221at the same intervals in the circumferential direction CR, and the number of through-holes included in each through-hole row may increase as the distance from the discharge section314increases in the circumferential direction CR. Thus, in the discharge path310, a negative pressure due to the suction unit35is likely to be applied to the side away upstream from the discharge section314. The speed difference between the flow speeds of air flows passing through the plurality of through-holes222provided in the screen221is likely to reduce. Thus, variation in defibration degree of the defibrated material discharged to the discharge path310can be reduced.

In the embodiment, the discharge section314does not need to be provided in the outer circumferential wall351. For instance, the discharge section314may be provided in one of the side wall353and the side wall352of the housing311. For instance, when the discharge section314is provided in the side wall353, the discharge section314may be opposed to the screen221, or may be opposed to the side wall352and may not be opposed to the screen221. In this case, the blocking member601is provided in a region of the downstream-side screen221D, the region not being opposed to the discharge section314. That is, the blocking member601blocks the openings of the through-holes222by covering the downstream-side screen221D. The blocking member601is provided in the outer circumferential surface, close to the discharge path310, of the downstream-side screen221D to block the openings, close to the outer circumferential surface, of the through-holes222. Thus, communication between the defibrating chamber210and the discharge path310via the through-holes222can be blocked. Thus, it is possible to change the number of communication holes Ch provided in the downstream-side screen221D to form a region with a smaller number of communication holes Ch in the downstream-side screen221D. In this case, the plurality of through-holes222provided in the screen221do not need to have the same shape.

In the embodiment, the defibrating apparatus200may not be disposed in the sheet manufacturing apparatus100in a posture in which the axis AR is horizontal. In this case, the defibrating apparatus200may be disposed in the sheet manufacturing apparatus100in an inclined posture in which the axis AR intersects a horizontal direction under the condition that the discharge section314is located at the lowest position of the outer circumferential wall351.

In the embodiment, the defibrating apparatus200may not be disposed in the sheet manufacturing apparatus100in a posture in which the discharge section314and the discharge pipe30are vertically downward from the axis AR. For instance, the defibrating apparatus200may be disposed in the sheet manufacturing apparatus100in a posture in which the discharge section314and the discharge pipe30are vertically upward from the axis AR. For instance, the defibrating apparatus200may be disposed in the sheet manufacturing apparatus100in a posture in which the discharge section314and the discharge pipe30are arranged side-by-side horizontally with the axis AR.

In the embodiment, the interval W between the outer circumferential wall351and the screen221may decrease stepwise as the distance from the discharge section314increases in the circumferential direction CR. For instance, in the discharge path310, let width W1be the width W of the region located in −Z direction from the axis AR, and let width W3greater than the width W1be the width W of the region located in +Z direction from the axis AR, then in the discharge path310, the width W of the region connecting the region located in −Z direction from the axis AR and the region located in +Z direction from the axis AR may decrease stepwise as the distance from the region located in +Z direction from the axis AR increases toward the region located in −Z direction from the axis AR. Alternatively, in the discharge path310, the width W of the region connecting the region located in −Z direction from the axis AR and the region located in +Z direction from the axis AR may be smaller than the width W3and larger than the width W1.

In the embodiment, when the discharge path310is seen from −Y direction side as illustrated inFIG.14, the discharge path310may have an asymmetric shape provided that in the discharge path310, a clockwise air flow toward the discharge section314is generated in the region on +X direction side of the discharge section314, and a counterclockwise air flow toward the discharge section314is generated in the region on −X direction side of the discharge section314. In this case, for instance, the width W2may be different from the width W4, and the region with the smallest width W may be displaced in the X-axis direction from the position in −Z direction from the axis AR. For instance, the interval D between the side wall352and the side wall353may differ between the region on +X direction side of the discharge section314and the region on −X direction side of the discharge section314.

In the embodiment, a fixed blade may be provided in the region opposed to the rotary blades503, in the inner circumferential surface of the screen221. The fixed blade defibrates the raw material MA introduced between the rotary blades503. In this case, the fixed blade may be fixed to the inner circumferential surface of the screen221with a clearance between the fixed blade and the tip ends of the rotary blades503. As illustrated inFIG.14, when the screen221is seen from −Y direction side, the fixed blade has a sharp shape projecting from the screen221to the rotary blades503, and the shape may extend in the Y-axis direction. When a plurality of fixed blades are provided, they may be provided over the entire circumference of the screen221at intervals in the circumferential direction CR. Alternatively, the fixed blades may be provided in a region on the inner circumferential surface of the screen221, the region being on the surface on the opposite side of the outer circumferential surface in which the blocking member601is provided.

In the embodiment, the supply unit214does not need to be circular as long as it is a through-hole that penetrates the side wall212in the Y-axis direction. For instance, the supply unit214may be polygonal or elliptic, or arc-shaped centered on the axis AR.

In the embodiment, the supply unit214does not need to be opened at a position vertically upward from the axis AR in the side wall212. For instance, the supply unit214may be opened at a position located side-by-side horizontally with the axis AR in the side wall212.

In the embodiment, the discharge section314may be circular as seen in the Z-axis direction. The dimension of the opening edge315in the Y-axis direction does not need to be the same as the inner dimension of the discharge path310in the Y-axis direction. In this case, for instance, the dimension of the opening edge315in the Y-axis direction may be smaller than the inner dimension of the discharge path310in the Y-axis direction.

In the embodiment, the dimension of the blocking member601in the Y-axis direction does not need to be the same as the dimension of the discharge path310in the Y-axis direction. For instance, the dimension of the blocking member601in the Y-axis direction may be smaller than the dimension of the discharge path310in the Y-axis direction. Alternatively, the dimension of the blocking member601in the X-axis direction may be the same as or smaller than the dimension of the opening edge315in the discharge section314in the X-axis direction. The blocking member601does not need to be rectangular. For instance, the blocking member601may be circular or oval.

In the embodiment, the defibrating apparatus200does not need to be provided with the blocking member601. In this case, in the screen221, the region RD may be provided with through-holes222so that the number of through-holes222provided per unit area in the region RD is less than the number in the region ERD. Alternatively, the inner circumferential surface of the screen221corresponding to the region RD may be provided with the above-described fixed blade so that the number of communication holes Ch in the region RD is less than the number in the region ERD. In this case, the fixed blade is provided in the inner circumferential surface, facing the defibrating chamber210, of the screen221, and may be regarded as an example of a blocking member that blocks the openings, close to the inner circumferential surface, of the through-holes222.

In the embodiment, the housings311,312,313do not need to cover the outside of the screen221over the entire circumference in the circumferential direction CR. In addition, the discharge path310does not need to be provided outside of the screen221over the entire circumference in the circumferential direction CR. For instance, in the embodiment, the region between the outside of the screen221partially covered by the housing311and the outer circumferential wall351of the housing311may serves as the discharge path310. In this case, in the screen221, the region not covered by the housing311does not need to be provided with through-holes222.

In the embodiment, the interval W between the outer circumferential wall351and the screen221may be constant in the circumferential direction CR of the screen221. In this case, the flow path cross-sectional area of the discharge path310may be unchanged, and constant in the circumferential direction CR of the screen221.

In the embodiment, the number of communication holes Ch in the same shape provided per unit area is made less in the downstream-side screen221D than in the upstream-side screen221U, thus when the downstream-side screen221D and the upstream-side screen221U with the same area are compared, air is more unlikely to pass through in the downstream-side screen221D than in the upstream-side screen221U. Alternatively, the shapes of the communication holes Ch may be made different between the downstream-side screen221D and the upstream-side screen221U so that air is more unlikely to pass through in the downstream-side screen221D than in the upstream-side screen221U. For instance, the hole diameter of the communication holes Ch provided in the downstream-side screen221D may be made smaller than the hole diameter in the upstream-side screen221U, thus when the downstream-side screen221D and the upstream-side screen221U with the same area are compared to each other, air is more unlikely to pass through in the downstream-side screen221D than in the upstream-side screen221U. In this case, the number of communication holes Ch provided per unit area in the downstream-side screen221D may be the same as or less than the number in the upstream-side screen221U.