JP7809546B2 - Protective device, crushing device, and method for installing the protective device - Google Patents

Description

This disclosure relates to a protective device, a crushing device, and a method for installing the protective device.

Inside the mill, the powdered raw material is blown upward by the carrier gas supplied from the outer periphery of the grinding table. Collisions of the blown-up powder with the shafts of the grinding rollers located above the outer periphery of the grinding table and the roller supports that support the grinding rollers cause wear, making countermeasures for wear in these areas an issue. Patent Document 1 discloses that by covering the areas that are hit by the carrier gas blown out from the outlet with a shield, wear on the grinding rollers caused by the pulverized fuel blown up by the carrier gas is reduced. Patent Document 1 also teaches that to prevent the pulverized fuel blown up by the carrier gas from accumulating on the inner surface of the shield, the inner surface of the shield is inclined at an angle greater than the angle of repose of the pulverized fuel, promoting the discharge of the pulverized fuel.

Patent No. 6779009

However, if powder with a relatively large particle size enters the space formed between the grinding roller and the shield from above, the powder cannot be expelled from the space and instead accumulates on the inner surface of the shield. This occurs because powder with a particle size larger than the gap formed between the grinding roller and the shield cannot pass through the gap, even if the shield is inclined at an angle greater than the angle of repose of the powder.

When powder accumulates on the inner surface of the shield, it enters the space formed between the crushing roller and the shield, preventing it from being smoothly discharged, and becomes a starting point for the powder to accumulate on the inner surface of the shield. Furthermore, when the crushing roller rotates with powder accumulated on the inner surface of the shield, the powder is constantly stirred up within the space, and collisions and friction with the powder cause wear on the inner surfaces of the crushing roller and shield.

This disclosure was made in light of these circumstances, and aims to provide a protective device, a crushing device, and a method for installing a protective device that can prevent powder from accumulating in the space formed between the crushing roller and a protective member that protects the crushing roller unit from powder transported by the carrier gas, and thereby prevent wear on the inner surfaces of the crushing roller and protective member.

In order to solve the above problems, the present disclosure employs the following means.
A protective device according to one aspect of the present disclosure is a protective device attached to a crushing device that crushes raw materials, the crushing device comprising: a crushing table; a crushing roller unit that crushes the raw materials supplied to the crushing table from a raw material supply unit between the crushing table and the crushing roller unit; and an outlet that is provided on the outer periphery of the crushing table and blows out a conveying gas upward. The crushing roller unit has a journal head attached to a housing, a journal shaft that is supported by the journal head and extends along an axis, and a crushing roller attached to the journal shaft so as to be rotatable around the axis. The protective device comprises: a protective member that surrounds a lower portion of the journal shaft at a position where the journal head and the crushing roller are adjacent to each other and protects the crushing roller unit from crushed material produced from the raw materials transported by the conveying gas; and a blocking portion that blocks the area above the protective member to prevent the crushed material from entering the space formed between the crushing roller and the protective member.

A protective device installation method according to one aspect of the present disclosure is a method for installing a protective device on a crushing device that crushes raw materials, the method including: a crushing table; a crushing roller unit that crushes the raw materials supplied to the crushing table from a raw material supply unit between the crushing table and the crushing roller unit; and an outlet provided on the outer periphery of the crushing table and that blows a conveying gas upward; the crushing roller unit having a journal head attached to a housing; a journal shaft supported by the journal head and extending along an axis; and a crushing roller attached to the journal shaft so as to be rotatable about the axis; the protective device having a protective member that surrounds a lower portion of the journal shaft to protect the crushing roller unit from crushed material produced by crushing the raw materials transported by the conveying gas and that is attached at a position adjacent to the journal head and the crushing roller; and a blocking portion that blocks the area above the protective member; and an installation step of attaching the blocking portion to prevent the crushed material from entering a space formed between the crushing roller and the protective member.

This disclosure provides a protective device, a crushing device, and a method for installing a protective device that can prevent crushed material from accumulating in the space formed between the crushing roller and a protective member that protects the crushing roller unit from crushed material transported by the carrier gas, and prevent wear on the inner surfaces of the crushing roller and protective member.

FIG. 2 is a vertical cross-sectional view showing the main configuration of a crusher. FIG. 2 is a perspective view showing a part of the internal configuration of the crusher. FIG. 3 is a vertical cross-sectional view of the crushing roller unit shown in FIG. 2 . FIG. 4 is a side view of a main part of the crushing roller unit shown in FIG. 3 . 3 is a perspective view showing a main part of the crushing roller unit shown in FIG. 2 with the crushing roller removed. FIG. FIG. 4 is a partial enlarged view of a portion B of the crushing roller unit shown in FIG. 3 . FIG. 4 is a top view of the crushing roller unit shown in FIG. 3 . FIG. 2 is a front view showing a main part of the crushing roller unit with the crushing roller removed. 9 is a cross-sectional view of the blocking portion shown in FIG. 8 taken along the line CC. FIG. 10 is a diagram showing a blocking portion of a modified example. FIG. 10 is a front view showing a crushing roller unit according to a second embodiment, illustrating a main part of the crushing roller unit with the crushing roller removed. FIG. 12 is a top view of the blocking portion shown in FIG. 11 . FIG. 10 is a diagram showing a blocking portion of a modified example. FIG. 10 is a front view showing a crushing roller unit according to a third embodiment, illustrating a main part of the crushing roller unit with the crushing roller removed. 15A and 15B are diagrams illustrating a modification of the blocking portion shown in FIG. 14. FIG. 16 is a partial enlarged view of a portion D of the crushing roller unit shown in FIG. 15 . FIG. 10 is a diagram showing a crushing roller unit according to a fourth embodiment, illustrating a main part of the crushing roller unit with the crushing roller removed.

First Embodiment
A first embodiment of the present disclosure will be described below with reference to the drawings. Note that the embodiment described below is merely an example, and is not intended to exclude various modifications or applications of techniques not explicitly described in the following embodiment. The configurations of the following embodiment can be implemented in various modifications without departing from the spirit thereof, and can be selected or combined as needed.

The pulverizer (pulverizing device) 10 according to the present disclosure is used to pulverize raw materials into fine powder, and is typically a fine pulverizer (mill) that pulverizes carbon-containing solid fuels such as coal to produce finely pulverized fuel. The pulverizer can also be used to pulverize solid fuels such as biomass fuel and petroleum coke, ore, and other raw materials.

Note that in the following explanations, "up and down" refers to up and down in the vertical direction (the direction of gravity), and "left and right" refers to opposite directions in the horizontal direction relative to a certain subject.

[Configuration of the pulverizer]
The configuration of a pulverizer 10 according to this embodiment will be described with reference to FIG. 1. FIG. 1 is a vertical cross-sectional view showing the configuration of the main components of the pulverizer 10. As shown in FIG. 2, the pulverizer 10, also known as a vertical mill, includes a vertical, hollow cylindrical housing 11. An input pipe 14, through which raw material to be pulverized, e.g., solid fuel such as coal, is input, is disposed on a central axis C1 of a ceiling portion 11a of the housing 11. A pulverizer table 13, which pulverizes the raw material input from the input pipe 14, is disposed on a base 12 directly below the input pipe 14. The pulverizer table 13 is driven to rotate about a vertical axis along the central axis C1 by a drive unit (not shown).

A circular grinding surface 13a is formed on the vertical upper surface of the grinding table 13, concentric with the central axis C1. Vertically above the grinding surface 13a, multiple (e.g., two or three) grinding rollers 21 are arranged at equal intervals around the circumference, facing the grinding surface 13a. Each grinding roller 21 is rotatably supported at the tip of a journal shaft (rotation support shaft) 22, which is arranged so as to tilt vertically downward from the peripheral wall 11b of the housing 11 toward the central axis C1.

The journal shaft 22 is a shaft member supported by the journal head 23 and extending along the axis Y1. The crushing roller 21, journal shaft 22, and journal head 23 are included in the crushing roller unit 20. The crushing roller unit 20 is a device that crushes raw material supplied to the crushing table 13 from the feed pipe 14 between itself and the crushing table 13.

The journal head 23 is provided with pivot pins 24 that extend tangentially to the outer periphery of the grinding table 13 and protrude from the housing 11 on both sides (one tangential direction and the other). The grinding roller unit 20 is supported on the peripheral wall 11b via the pivot pins 24 so that it can swing toward and away from the grinding surface 13a.

As shown in Figure 1, the journal head 23 has a protrusion 23a that protrudes vertically downward, and a stopper 25 is attached to the peripheral wall 11b of the housing 11. The tip of the stopper 25 abuts against the protrusion 23a, restricting the approach of the crushing roller 21 to the crushing surface 13a. The stopper 25 is driven forward and backward by an actuator 25a, which adjusts the position of its tip and adjusts the closest position of the crushing roller 21 to the crushing surface 13a.

The crushing roller 21 also has a biasing device 26 that applies a load to crush the raw material. The biasing device 26 includes a hydraulic cylinder 26a fixed to the peripheral wall 11b and a plunger 26b that is driven axially by the hydraulic cylinder 26a. An arm portion 23b extends from the upper part of the journal head 23, and when the tip of the plunger 26b is pressed against the arm portion 23b, a downward load (toward the crushing surface 13a) is applied to the crushing roller 21 to crush the raw material on the crushing surface 13a.

An inlet port 15, located below the grinding table 13, is provided at the bottom of the housing 11 and through which carrier gas is fed. In this embodiment, air compressed by a blower (not shown) is fed into the housing 11 from this inlet port 15 as carrier gas, creating a high-pressure atmosphere inside the housing 11.

A rotary separator (classifying device) 17 is provided at the top of the housing 11, positioned around the outer periphery of the input tube 14, and classifies the pulverized raw material (hereinafter also referred to as powder or pulverized material) using a classifying blade 16. In addition, an outlet port 18 is provided in the ceiling portion 11a of the housing 11, through which the classified pulverized material is discharged outside the housing 11.

The raw material is crushed by the crushing roller 21 into pulverized material, and by driving a blower (not shown) connected to the inlet port 15, carrier gas is sent into the housing 11 from the inlet port 15. The upward swirling flow of carrier gas generated by the vanes 32a of the carrier gas outlet 32 (described below) causes the pulverized material to rise while drying.

The pulverized material that rises is separated by the rotary separator 17 into fine powder smaller than a specified particle size and coarse powder larger than a specified particle size. The fine powder passes through the rotary separator 17, rides on the flow of carrier gas, is discharged from the outlet port 18, and is transported from the pulverizer to another device (e.g., a boiler). The coarse powder either collides with the classification blade 16 of the rotary separator 17 and is repelled, or falls under its own weight while rising inside the housing 11, and is returned to the pulverizing table 13 for re-pulverization.

[Crushing roller unit and its peripheral configuration]
Next, the crushing roller unit 20 and its peripheral configuration will be described with reference to Figures 2 and 3. Figure 2 is a perspective view showing a part of the internal configuration of the crusher 10. Figure 3 is a vertical cross-sectional view of the crushing roller unit 20 shown in Figure 2.

As shown in Figures 2 and 3, an opening 11c is formed in the peripheral wall 11b of the housing 11. The journal head 23 is disposed in the opening 11c, and a swing shaft 24 protruding to the left and right is swingably supported on the peripheral wall 11b at the edge of the opening 11c. A cover 30 protruding radially from the peripheral wall 11b is attached to the opening 11c so as not to interfere with the journal head 23, separating the interior and exterior of the housing 11.

The crushing roller 21 is attached to a journal shaft 22 so as to be rotatable about axis Y1. The crushing roller 21 has a roller housing 21a with a shaft-shaped portion 21b and a roller body portion 21c that is fitted over the roller housing 21a and is detachable. The journal head 23 has a roller support portion 23c that supports the crushing roller 21. The protrusion portion 23a, arm portion 23b, and swing shaft 24 protrude downward, upward, left, and right from the roller support portion 23c and are supported by and in contact with a stopper 25, plunger 26b, and peripheral wall 11b, respectively.

The end (one end) of the journal shaft 22 facing the cover 30 is connected to the roller support portion 23c of the journal head 23. The roller housing 21a of the crushing roller 21 is rotatably attached to the end of the journal shaft 22 facing the central axis C1. The axis of the journal shaft 22 is inclined downward from the peripheral wall 11b of the housing 11 toward the central axis C1, with the inclination angle α being, for example, between 15 degrees and 40 degrees.

The carrier gas outlet 32 is located on the outer periphery of the grinding table 13 and is a device that blows carrier gas upward. The carrier gas is sent into the housing 11 by a blower (not shown) connected to the inlet port 15, and is blown upward from the carrier gas outlet 32, which is located between the outer periphery of the grinding table 13 and the peripheral wall 11b of the housing 11, as shown by arrow A1 in Figure 3.

Vane 32a is provided at the carrier gas outlet 32 on the outer periphery of the grinding table 13. The vane 32a applies a rotational force to the carrier gas blown vertically upward from the carrier gas outlet 32, forming a swirling upward flow that rotates spirally within the housing 11.

Directly above the carrier gas outlet 32 are the roller housing 21a of the grinding roller 21, the roller support portion 23c of the journal head 23, and the oscillating shaft 24. Therefore, the carrier gas blown from below toward the upward direction is blown onto the downward-facing surfaces of the roller housing 21a, roller support portion 23c, and oscillating shaft 24.

Inside the housing 11, the crushed material (powder) crushed by the crushing roller 21 on the crushing table 13 is blown up by the flow of this conveying gas, and some of it is blown onto the shaft portion 21b of the roller housing 21a, the roller support portion 23c, and the downward-facing surface of the oscillating shaft 24. When the powder collides with the downward-facing surfaces of these device parts, it causes wear and other damage at the collision points. For this reason, in the crushing roller unit 20, a roller journal protector (protective device) 27 is attached to the roller journal portion 20J, which includes the roller support portion 23c of the journal head 23 and the shaft portion 21b of the crushing roller 21.

[Configuration of roller journal protector]
The roller journal protector 27 is a member that surrounds the lower portion of the journal shaft 22 at the position where the journal head 23 and the crushing roller 21 are adjacent to each other, and protects the crushing roller unit 20 from collision with powder carried by the carrier gas.

Figure 4 is a side view of the main parts of the crushing roller unit 20 shown in Figure 2. As shown in Figure 4, the roller journal protector 27 has an apron-shaped panel (mounting panel member) 27a and a shield (protective member) 27b. The apron-shaped panel 27a is detachably attached to the roller support portion 23c and protrusion portion 23a of the journal head 23.

The shield 27b is attached so that its base end 27bA is fixed to the apron-shaped panel 27a and surrounds the lower portion of the shaft-shaped portion 21b of the roller housing 21a. The apron-shaped panel 27a and shield 27b are made of steel (e.g., SS400, low-alloy steel, etc.).

The apron-shaped panel 27a is a flat plate that is attached to the roller support part 23c so that it extends around the roller support part 23c. The apron-shaped panel 27a not only attaches the shield 27b to the roller support part 23c, but also protects the roller support part 23c, the protrusion 23a, and the oscillating shaft 24 from collisions with the powder being transported.

Figure 5 is a perspective view showing the main parts of the crushing roller unit 20 with the crushing roller 21 shown in Figure 2 removed. The blocking portion 28, which will be described later, is not shown in Figure 5. As shown in Figure 5, the apron-shaped panel 27a is attached to the roller support portion 23c and is positioned in a plane perpendicular to the axis Y1 so as to extend over a substantially fixed distance from the outer periphery of the roller support portion 23c. The apron-shaped panel 27a is positioned so as to block a portion of the opening 11c in the peripheral wall 11b of the housing 11.

In areas of the surface of the apron-shaped panel 27a (the surface that receives the carrier gas from the carrier gas outlet 32) where powder collisions occur relatively frequently, ceramic tiles 27c made of hard ceramic, which have better wear resistance than the apron-shaped panel 27a, may be attached to reduce wear caused by powder collisions. Examples of hard ceramics include alumina, silica, zirconia, magnesia, silicon carbide, silicon nitride, etc., or mixtures of these. Alternatively, hardened ceramic plates may be used instead of ceramic tiles.

As shown in Figures 4 and 5, the shield 27b is formed in a semi-frustum shape so as to surround the semi-cylindrical region inside the peripheral wall 11b of the housing 11 at the vertically lower portion of the shaft portion 21b of the crushing roller 21. As shown in Figure 4, the shield 27b is formed in a semi-frustum shape (semi-polygonal truncated pyramid shape) with the other tip portion 27bB extending toward the roller main body 21c, surrounding the vertically lower portion of the shaft portion 21b. Powder is blown onto the vertically lower portion of the shaft portion 21b by the airflow of the carrier gas from the carrier gas outlet 32, but is protected by the shield 27b.

A ceramic tile (wear-resistant member) 27d made of a hard ceramic with better wear resistance than the shield 27b may be attached to the surface of the shield 27b (the surface that is hit by the carrier gas from the carrier gas outlet 32) to protect it from powder collisions. Examples of hard ceramics include alumina, silica, zirconia, magnesia, silicon carbide, silicon nitride, etc., or mixtures of these. Alternatively, a hardened plate may be used instead of the ceramic tile.

The shield 27b is shaped like a semi-frustum, and its diameter increases from the base end 27bA to the tip end 27bB in line with the outer periphery of the crushing roller 21, which increases in diameter from the shaft portion 21b to the roller body portion 21c. When the shield 27b is attached, the vertically lower region 27bC of the semi-frustum shape (here, the bottommost flat panel portion) is formed so that it slopes downward from the horizontal at an angle θ greater than or equal to the angle of repose of the powder from the base end 27bA to the tip end 27bB (toward the center of the housing 11).

Except for the lower region 27bC of the semi-frustum shape of the shield 27b, the entire surface is inclined downward from the horizontal from the base end 27bA to the tip end 27bB at an angle equal to or greater than that of the lower region 27bC. Therefore, the inner surface of the shield 27b (the upward-facing surface opposite the surface) is inclined at an angle equal to or greater than the angle of repose of the powder at every point.

The angle of repose of the powder is determined by the physical properties (powder characteristics) of the pulverized material and the condition of the inner surface of the shield 27b, so it is preferable to set the angle θ according to the type of raw material and the properties of the pulverized material (particle size distribution, etc.). It is even more preferable to set the angle θ to a value that is larger than the angle of repose of the powder and that covers the area that the powder hits as it is blown in the carrier gas airflow, while still allowing for some leeway within the placement space within the housing 11. For example, if the powder is pulverized coal, the angle θ should preferably be in the range of 40 degrees to 50 degrees.

[Configuration of intrusion prevention member]
Fig. 6 is a partial enlarged view of portion B of the crushing roller unit 20 shown in Fig. 3. As shown in Fig. 6, a narrow space S1 is formed between the shaft portion 21b of the crushing roller 21 and the shield 27b. The narrow space S1 communicates with the internal space S2 of the housing 11 below via a gap CL1 formed at the position where the shaft portion 21b of the crushing roller 21 and the shield 27b are closest to each other.

The crushing roller unit 20 of this embodiment has an intrusion prevention member 29 that prevents crushed material from entering the journal shaft 22 side of the narrow space S1 at the position where the journal head 23 and crushing roller 21 are adjacent. The intrusion prevention member 29 is a member with an L-shaped cross section that is fixed to the roller support portion 23c of the journal head 23. As shown in Figure 6, the intrusion prevention member 29, together with the shaft portion 21b and shield 27b of the crushing roller 21, forms the narrow space S1.

[Configuration of blocking portion]
6, the shield 27b is disposed with a first distance L1 between it and the shaft portion 21b of the crushing roller 21. If the diameter D1 of the coarse particles LF is larger than the first distance L1 between the shaft portion 21b and the shield 27b in the gap CL1, the coarse particles LF cannot pass through the gap CL1 and move into the internal space S2 of the housing 11. In this case, the coarse particles LF accumulate in the narrow space S1.

The roller journal protector 27 of the crushing roller unit 20 of this embodiment has a blocking portion 28 that blocks the area above the shield 27b to prevent coarse particles LF (part of the pulverized material obtained by crushing raw materials) from entering the narrow space S1 formed between the shaft portion 21b of the crushing roller 21 and the shield 27b. The blocking portion 28 prevents the coarse particles LF from entering the narrow space S1.

Figure 7 is a top view of the crushing roller unit 20 shown in Figure 3. As shown in Figure 7, the blocking portions 28 are arranged in two locations, upstream and downstream in the rotation direction RD of the crushing roller 21, so as to cover the space above the shield 27b, which is arranged in a radial direction perpendicular to the axis Y1 of the journal shaft 22. One radial end of the blocking portion 28 is fixed to the upper end of the shield 27b, and the other radial end is arranged so as to be close to the shaft portion 21b of the crushing roller 21 and the intrusion prevention member 29.

Figure 8 is a front view showing the main parts of the crushing roller unit 20 with the crushing roller 21 removed. Figure 9 is a cross-sectional view of the blocking portion 28 shown in Figure 8 taken along the arrows C-C. As shown in Figure 8, one end of the blocking portion 28 is fixed to the flat portion 27b1 formed on the upper end of the shield 27b. The blocking portion 28 and the flat portion 27b1 are fixed together, for example, by inserting a fastening bolt (not shown) into a through-hole (not shown) that passes through the blocking portion 28 and the flat portion 27b1, and then tightening a fastening nut (not shown).

As shown in Figures 8 and 9, the blocking portion 28 has a first portion 28a arranged on the journal head 23 side along the axis Y1, and a second portion 28b arranged on the crushing roller 21 side. The first portion 28a is arranged close to both the portion of radius R1 of the intrusion prevention member 29 and the portion of radius R1 of the shaft portion 21b of the crushing roller 21. The second portion 28b is arranged close to the radius R2 (larger than radius R1) of the shaft portion 21b of the crushing roller 21.

As shown in FIG. 8, the first portion 28a is positioned a second distance L2 away from the portion of the shaft portion 21b of the crushing roller 21 with radius R1 in the radial direction perpendicular to the axis Y1. The second portion 28b is positioned a second distance L2 away from the portion of the shaft portion 21b of the crushing roller 21 with radius R2 in the radial direction perpendicular to the axis Y1. It is desirable that the second distance L2 be equal to or greater than the average particle size of the crushed product produced by the crusher 10.

This is because particles that have been pulverized to a size below the average particle size of the pulverized product are selectively discharged from the pulverizer 10 due to the action of the pulverizer's 10 classifier, and particles smaller than the average particle size of the pulverized product are concentrated relatively less in the mill. Therefore, even if the second distance L2 is reduced beyond the average particle size of the pulverized product, the blocking portion 28 does not become more effective in preventing particles from entering the narrow space S1, and instead only increases the risk of contact between the blocking portion 28 and the shaft-shaped portion 21b.

The average particle size of the pulverized product is, for example, approximately 75 μm in the case of a pulverizer 10 used in a boiler (not shown) that uses pulverized coal as fuel. This is the product particle size of pulverized coal that is suitable for combustion in a burner (not shown) to which the pulverized material is supplied from the pulverizer 10. If the particle size of the pulverized coal is too large, it will not be completely burned in the burner, increasing the amount of unburned material in the ash and worsening fuel efficiency. Conversely, if the particle size is too small, the combustibility in the burner will be too high, increasing the amount of nitrogen oxides (NOx) generated and increasing the power required to pulverize the raw material in the pulverizer 10.

The second portion 28b is positioned closer to the tip of the crushing roller 21 than the narrow space S1, and therefore does not prevent crushed material from entering the narrow space S1. The second portion 28b reduces the amount of crushed material flowing into the tip of the shield 27b and reduces the amount of crushed material flowing down the inner surface of the shield 27b. In this embodiment, the blocking portion 28 includes the second portion 28b, but it may also include only the first portion 28a without the second portion 28b.

The second distance L2 between the blocking portion 28 and the crushing roller 21 is shorter than the first distance L1 between the shield 27b and the crushing roller 21. This reliably prevents coarse particles LF of a size equal to or greater than the first distance L1 from entering the narrow space S1 formed between the shield 27b and the crushing roller 21 and accumulating in the narrow space.

It is desirable that the blocking portion 28 be formed so that the upper surface 28c slopes downward (at an inclination angle β) from the inner periphery close to the axis Y1 to the outer periphery away from the axis Y1 in the horizontal direction HD perpendicular to the axis Y1.

As shown in Figure 9, the blocking portion 28 is formed in a plate shape with an upper surface 28c that extends parallel to the axis Y1. The upper surface 28c guides the colliding coarse particles LF from the inner side to the outer side in the radial direction of the crushing roller 21.

The blocking portion 28 shown in Figure 9 has an upper surface 28c formed to extend parallel to the axis Y1, but other configurations are also possible. Figure 10 is a diagram showing a modified blocking portion 28A. The modified blocking portion 28A has a first portion 28Aa arranged on the journal head 23 side along the axis Y1, and a second portion 28Ab arranged on the crushing roller 21 side. The blocking portion 28A has an upper surface 28Ac formed to slope downward from the crushing roller 21 side toward the journal head 23 side with respect to the axis Y1.

In the modified blocking portion 28A, the upper surface 28Ac is formed so as to slope downward relative to the axis Y1 from the crushing roller 21 side toward the journal head 23 side. This makes it more difficult for the coarse particles LF to move along the axis Y1 from the journal head 23 side toward the crushing roller 21 side, compared to when the upper surface 28Ac of the blocking portion 28A is formed so as to extend parallel to the axis Y1. This prevents the coarse particles LF from entering and getting caught in the gap between the rotating crushing roller 21 and the blocking portion 28, thereby preventing wear on the crushing roller 21.

In this embodiment, the blocking portion 28 wears due to contact with other components caused by vibrations generated during operation of the crusher 10, or collisions with falling crushed material. If the blocking portion 28 wears out, it can be repaired by overlay welding. Alternatively, the blocking portion 28 may be removed and a new blocking portion 28 installed. The wear state of the blocking portion 28 is preferably checked by measuring the gap between the crushing roller 21 during periodic inspections, and repairing or replacing it if it exceeds a predetermined value (the value estimated to reach the first distance L1 of the gap CL1 in the narrow space S1 at the time of the next scheduled repair).

The blocking portion 28 of this embodiment may be retrofitted to a roller journal protector 27 that does not already have a blocking portion 28. In this case, since the existing roller journal protector 27 does not have a mounting seat for the blocking plate, the blocking portion 28 may be welded directly to the roller journal protector 27. It is preferable that the shape of the blocking portion 28 is pre-machined to the designed shape, but it may also be modified to suit the wear condition of the crushing roller 21 before installation.

When welding the blocking portion 28, it is preferable to remove the roller journal protector 27 from the crusher roller unit 20 and insulate it before welding to prevent stray current from flowing into the crusher roller unit 20. Furthermore, if the roller journal protector 27 is to be welded while the crusher roller unit 20 is still installed, it is preferable to take sufficient measures to prevent stray currents, such as providing a multi-point earth, before welding. Furthermore, if stray currents flow through the bearings of the crusher roller unit 20, arc discharges will occur on the rolling surfaces of the bearings, causing damage to the bearings.

The thickness of the blocking portion 28 is preferably the same as that of the shield 27b. This is because only one type of material thickness needs to be prepared when manufacturing the roller journal protector 27. However, if wear is severe, increasing the thickness of the blocking portion 28 can improve the lifespan of the blocking portion 28, so the thickness may be changed depending on the circumstances. The blocking portion 28 may be welded to the shield 27b or may be fixed by extending an arm from a non-rotating part (such as the journal head 23).

The method for attaching a protective device to the crusher 10 of this embodiment includes a first attachment step and a second attachment step. The first attachment step is a step of attaching a shield 27b to a position adjacent to the journal head 23 and crushing roller 21, surrounding the lower portion of the journal shaft 22 and protecting the crushing roller unit 20 from solid fuel transported by the carrier gas. The second attachment step is a step of attaching a blocking portion 28 that blocks the area above the shield 27b to prevent crushed material from entering the narrow space S1 formed between the crushing roller 21 and the shield 27b.

In the protective device installation method of this embodiment, the second installation step may be performed after the first installation step. That is, the shield 27b may be installed on the crusher 10, and then the blocking portion 28 may be installed on the crusher 10. Also, in the protective device installation method of this embodiment, the first installation step may be performed after the second installation step. That is, the shield 27b may be installed on the crusher 10, and then the blocking portion 28 may be installed on the shield 27b.

The operation and effects of the crusher 10 of the present embodiment described above will now be described.
According to the crusher 10 of this embodiment, the carrier gas blown out from the carrier gas outlet 32 carries the crushed material upward inside the housing 11. The crushed material transported upward from the carrier gas outlet 32 toward the crushing roller 21 collides with the shield 27b, so that the crushing roller 21 is not worn down by collisions with the crushed material.

The shield 27b surrounds the lower portion of the journal shaft 22 where the journal head 23 and crushing roller 21 are adjacent, but the upper portion of the journal shaft 22 is open. Therefore, if the upper portion of the journal shaft 22 remains open, the crushed material blown up will fall onto the upper portion of the journal shaft 22 and enter the narrow space S1 formed between the crushing roller 21 and the shield 27b.

Powdered material with a particle size smaller than the gap CL1 formed between the crushing roller 21 and the shield 27b falls through the gap CL1 into the internal space S2 and does not accumulate on the inner surface of the shield 27b. On the other hand, powdered material with a particle size larger than the gap CL1 formed between the crushing roller 21 and the shield 27b does not fall through the gap CL1 into the internal space S2 and instead accumulates on the inner surface of the shield 27b.

In the crusher 10 of this embodiment, the blocking portion 28 blocks the area above the shield 27b to prevent crushed material from entering the narrow space S1 formed between the crushing roller 21 and the shield 27b. Therefore, even if crushed material with a particle size larger than the gap CL1 formed between the crushing roller 21 and the shield 27b falls from above the shield 27b, the blocking portion 28 prevents the material from entering the narrow space S1. This prevents the crushed material from accumulating in the narrow space S1 formed between the shield 27b and the crushing roller 21, thereby preventing wear on the inner surfaces of the crushing roller 21 and the shield 27b.

In the crusher 10 of this embodiment, the second distance L2 between the blocking portion 28 and the crushing roller 21 is shorter than the first distance L1 between the shield 27b and the crushing roller 21. This reliably prevents crushed material of a size exceeding the first distance L1 from entering the narrow space S1 formed between the shield 27b and the crushing roller 21 and accumulating in the narrow space S1.

Second Embodiment
Next, a crushing roller unit 20B according to a second embodiment of the present disclosure will be described with reference to FIG. 11 . FIG. 11 is a front view showing the crushing roller unit 20B according to the second embodiment. In FIG. 11 , the horizontal direction HD is a direction that is perpendicular to the axis Y1 of the journal shaft 22 and extends horizontally. FIG. 11 shows the state in which the crushing roller 21 has been removed. The crushing roller unit 20B according to this embodiment is similar to the crushing roller unit 20 according to the first embodiment, except for the points described below.

As shown in FIG. 11, the blocking portion 28B has a first portion 28Ba arranged on the journal head 23 side along the axis Y1, and a second portion 28Bb arranged on the crushing roller 21 side. The first portion 28Ba is arranged close to both the radius R1 portion of the intrusion prevention member 29 and the radius R1 portion of the shaft portion 21b of the crushing roller 21. The second portion 28Bb is arranged close to the radius R2 portion of the shaft portion 21b of the crushing roller 21.

As shown in FIG. 11, in the crushing roller unit 20B of this embodiment, one end of the blocking portion 28B is fixed to the flat portion 27b1 formed at the upper end of the shield 27b. The blocking portion 28B and the flat portion 27b1 are fixed together by inserting a fastening bolt 41 into a through-hole that passes through the blocking portion 28B and the flat portion 27b1, and tightening a fastening nut 42 onto the shaft portion 41a of the fastening bolt 41.

Figure 12 is a top view of the blocking portion 28B shown in Figure 11. In Figure 12, the axial direction AD is the direction along the axis Y1 of the journal shaft 22. As shown in Figure 12, a through hole 28Bd extending in a direction perpendicular to the axial direction AD is formed in the blocking portion 28B. The shank 41a of the fastening bolt 41 is inserted into the through hole 28Bd. A fastening nut 42 is fastened to the shank 41a.

The blocking portion 28B can be moved in a direction perpendicular to the axial direction AD by loosening the fastening bolt 41 and fastening nut 42. The position of the blocking portion 28B in the direction perpendicular to the axial direction AD is fixed by adjusting the position of the blocking portion 28B in the direction perpendicular to the axial direction AD and then fastening the fastening bolt 41 and fastening nut 42. In this way, the blocking portion 28B is fixed to the shield 27b so that it can be moved in a direction perpendicular to the axial direction AD.

The blocking portion 28B shown in Figure 12 is fixed to the shield 27b so that it can move in a direction perpendicular to the axial direction AD, but other configurations are also possible. For example, the blocking portion 28B may be fixed so that it can move in both a direction perpendicular to the axial direction AD and in the axial direction AD, as in the modified example shown in Figure 13.

As an example, as shown in FIG. 13, a through hole 27b2 extending along the axial direction AD is formed in the flat surface 27b1 of the shield 27b. The shaft 41a of the fastening bolt 41 is inserted into the through hole 27b2 and through hole 28Bd. A fastening nut 42 is fastened to the shaft 41a.

The blocking portion 28B can be moved in both the direction perpendicular to the axial direction AD and in the axial direction AD by loosening the fastening bolt 41 and fastening nut 42. The position of the blocking portion 28B in the direction perpendicular to the axial direction AD and in the axial direction AD is fixed by adjusting the position of the blocking portion 28B in the direction perpendicular to the axial direction AD and in the axial direction AD, and then fastening the fastening bolt 41 and fastening nut 42.

In this way, the blocking portion 28B is fixed to the shield 27b so that it can move in both the radial direction perpendicular to the axial direction AD and in the axial direction AD. Note that the method for fixing the blocking portion 28B to the shield 27b is not limited to this. The blocking portion 28B may have any structure as long as it can be fixed so that it can move in both the direction perpendicular to the axial direction AD and in the axial direction AD.

In the crusher 10 of this embodiment, the blocking portion 28B can be moved relative to the shield 27b in a direction perpendicular to the axial direction AD and/or in the axial direction AD, thereby moving the blocking portion 28B to an appropriate position depending on the wear state of the blocking portion 28B, etc. This makes it possible to adjust the gap between the blocking portion 28B and the crushing roller 21, or the gap between the blocking portion 28B and the intrusion prevention member 29 of the journal head 23, to an appropriate distance to prevent the intrusion of crushed material.

Third Embodiment
Next, a crushing roller unit 20C according to a third embodiment of the present disclosure will be described with reference to Fig. 14. Fig. 14 is a front view showing the crushing roller unit 20C according to the third embodiment. Fig. 14 shows the state in which the crushing roller 21 has been removed. The crushing roller unit 20C according to this embodiment is similar to the crushing roller unit 20B according to the second embodiment, except for the points described below.

As shown in FIG. 14, the blocking portion 28B in this embodiment is a plate-shaped member. The thickness T1 of the second portion 28Bb at a position close to the shaft portion 21b of the crushing roller 21 is thicker than the thickness T2 at other positions. By making the thickness T1 of the blocking portion 28B at a position close to the crushing roller 21 thicker than the thickness T2 at other positions, it is possible to increase the durability of the blocking portion 28B against wear caused by crushed material caught between the crushing roller 21 and the blocking portion 28B.

The blocking portion 28B may be modified as shown in Figures 15 and 16. Figure 15 is a diagram showing a modified version of the blocking portion 28B shown in Figure 14. Figure 16 is a partial enlarged view of portion D of the crushing roller unit 20C shown in Figure 15. As shown in Figures 15 and 16, the modified blocking portion 28B has a second portion 28Bb of the blocking portion 28B that is located close to the crushing roller 21 and is thicker than the thickness at other positions.

In addition, the surface of the second portion 28Bb facing the shaft-shaped portion 21b is inclined so that it moves away from the shaft-shaped portion 21b from top to bottom. This allows the fine particles PF (part of the pulverized material) drawn between the tip of the second portion 28Bb and the shaft-shaped portion 21b to be smoothly guided downward into the narrow space S1. This prevents the fine particles PF from adhering between the second portion 28Bb and the shaft-shaped portion 21b.

Fourth Embodiment
Next, a crushing roller unit 20D according to a fourth embodiment of the present disclosure will be described with reference to Fig. 17. Fig. 17 is a front view showing the crushing roller unit 20D according to the fourth embodiment. Fig. 17 shows the crushing roller unit 20D with the crushing roller 21 removed. The crushing roller unit 20D according to this embodiment is similar to the crushing roller unit 20B according to the second embodiment, except for the points described below.

As shown in FIG. 17, the crushing roller unit 20D of this embodiment has a support member 28Bc that is positioned so as to contact both the underside of the blocking portion 28B and the surface of the shield 27b facing the narrow space S1. According to the crushing roller unit 20D of this embodiment, the support member 28Bc allows the blocking portion 28B to be securely fixed to the shield 27b.

The protective devices described in each of the above-described embodiments can be understood, for example, as follows:

A protective device according to one aspect of the present disclosure is a protective device attached to a crushing device (10) that crushes raw materials. The crushing device includes a crushing table (13), a crushing roller unit (300) that crushes the raw materials supplied to the crushing table from a raw material supply unit between the crushing table and the crushing roller unit, and an outlet (32) that is provided on the outer periphery of the crushing table and blows out a conveying gas upward. The crushing roller unit includes a journal head (23) attached to a housing (11), and a shaft supported by the journal head. The device has a journal shaft (22) extending along line (Y1) and a crushing roller (21) attached to the journal shaft so as to be rotatable about the axis. It also includes a protective member (27b) that surrounds the lower portion of the journal shaft at a position where the journal head and the crushing roller are adjacent and protects the crushing roller unit from crushed material produced by crushing the raw material transported by the carrier gas, and a blocking portion (28) that blocks the area above the protective member to prevent the solid fuel from entering the space (S1) formed between the crushing roller and the protective member.

In a protective device according to one aspect of the present disclosure, the carrier gas blown out from the outlet transports the pulverized material inside the housing upward. The pulverized material transported upward from the outlet toward the crushing roller collides with the protective member, preventing the crushing roller from being worn down by collisions with the solid fuel.

The protective member surrounds the lower portion of the journal shaft where the journal head and crushing roller are adjacent, but the upper portion of the journal shaft is open. Therefore, if the upper portion of the journal shaft remains open, crushed material blown up into the upper portion of the journal shaft falls and enters the space formed between the crushing roller and the protective member. Crushed material with a particle size smaller than the gap formed between the crushing roller and the protective member falls downward through the gap and does not accumulate on the inner surface of the protective member. On the other hand, crushed material with a particle size larger than the gap formed between the crushing roller and the protective member does not fall downward through the gap and accumulates on the inner surface of the protective member.

In a protective device according to one aspect of the present disclosure, the blocking portion blocks the area above the protective member to prevent crushed material from entering the space formed between the crushing roller and the protective member. Therefore, even if crushed material with a particle size larger than the gap formed between the crushing roller and the protective member falls from above the protective member, the blocking portion prevents it from entering the space. This prevents crushed material from accumulating in the space formed between the protective member and the crushing roller, which can cause wear on the inner surfaces of the crushing roller and the protective member.

In a protective device according to one aspect of the present disclosure, the protective member may be positioned at a first distance (L1) from the crushing roller, the blocking portion may be positioned at a second distance (L2) from the crushing roller, and the second distance may be shorter than the first distance.
With the protective device of this configuration, the second distance between the blocking portion and the crushing roller is shorter than the first distance between the protective member and the crushing roller, so that crushed material of a size equal to or larger than the first distance can be reliably prevented from entering the space formed between the protective member and the crushing roller and accumulating in the space.

In the protection device according to the aspect of the present disclosure, the blocking portion may have an upper surface that is formed to extend parallel to the axis.
According to the protection device of this configuration, the upper surface of the blocking portion is formed to extend parallel to the axis, so that crushed material that collides with the upper surface of the blocking portion can be guided in the radial direction.

In the protection device according to one aspect of the present disclosure, the blocking portion may have an upper surface that is formed to slope downward from the crushing roller toward the journal head with respect to the axis.
With this protective device, the upper surface of the blocking portion is formed to be inclined downward from the crushing roller toward the journal head with respect to the axis, which makes it more difficult for crushed material to move along the axis from the journal head side to the crushing roller side compared to when the upper surface of the blocking portion is formed to extend parallel to the axis. This makes it possible to prevent crushed material from getting caught in the gap between the rotating crushing roller and the blocking portion, thereby preventing wear on the crushing roller.

In the protection device having the above configuration, the blocking portion may have an upper surface that is formed so as to slope downward from the inner periphery toward the outer periphery in a horizontal direction (HD) perpendicular to the axis.
With the protective device of this configuration, the upper surface of the blocking portion is formed so as to slope downward in the radial direction from the inner side to the outer side, so that crushed material that collides with the upper surface of the blocking portion can be guided from the inner side to the outer side in the radial direction and discharged from the area above the protective member.

In the protection device of the above aspect, the blocking portion may be configured to be fixed to the protection member.
According to the protection device of this configuration, by fixing the blocking portion to the protection member, it is possible to easily and reliably block the area above the protection member.

In the protection device having the above configuration, the blocking portion may be fixed to the protection member so as to be movable in a direction along the axis and/or a radial direction perpendicular to the axis.
According to the protective device of this aspect, the blocking portion can be moved relative to the protective member in a direction along the axis and/or in a radial direction perpendicular to the axis, thereby moving the blocking portion to an appropriate position according to the wear state, etc. This makes it possible to adjust the gap between the blocking portion and the crushing roller or the gap between the blocking portion and the journal head to an appropriate distance to prevent the intrusion of crushed material.

In the protective device having the above configuration, the blocking portion may have a support member (28Bc) fixed to the upper end of the protective member and arranged to contact both the lower surface of the blocking portion and the surface of the protective member facing the space.
According to the protection device of this aspect, the load support member is arranged so as to contact both the underside of the blocking portion and the surface of the protection member facing the space, thereby making it possible to reliably fix the blocking portion to the protection member.

In the protection device according to one aspect of the present disclosure, the blocking portion may be a plate-shaped member, and may be configured so that the thickness of the blocking portion at a position adjacent to the crushing roller is greater than the thickness of other positions.
With this protective device, the thickness of the blocking portion at the position close to the crushing roller is made thicker than the thickness at other positions, thereby increasing the durability of the blocking portion against wear caused by crushed material that gets caught between the crushing roller and the blocking plate.

A crushing device according to one aspect of the present disclosure includes any one of the protection devices described above, a crushing table, a crushing roller unit that crushes the raw material supplied from a raw material supply unit to the crushing table between the crushing table and the table, and an outlet provided on the outer periphery of the crushing table and that blows out a conveying gas upward, and the crushing roller unit has a journal head attached to a housing, a journal shaft supported by the journal head and extending along an axis, and a crushing roller attached to the journal shaft so as to be rotatable around the axis.
According to one aspect of the crushing device of the present disclosure, powder can be prevented from accumulating in the space formed between the crushing roller and a protective member that protects the crushing roller unit from powder transported by the carrier gas, thereby preventing wear on the inner surfaces of the crushing roller and the protective member.

The method of installing the protective device described in each of the above-described embodiments can be understood, for example, as follows.

A method for installing a protective device according to one aspect of the present disclosure is a method for installing a protective device to a crushing device that crushes raw materials, the method comprising: a crushing table; a crushing roller unit (300) that crushes the raw material supplied from a raw material supply unit to the crushing table between the crushing table and the crushing roller unit; and an outlet provided on the outer periphery of the crushing table and that blows out a conveying gas upward; the crushing roller unit having a journal head attached to a housing; a journal shaft supported by the journal head and extending along an axis; and a crushing roller attached to the journal shaft so as to be rotatable around the axis; the protective device having a protective member that surrounds a lower portion of the journal shaft to protect the crushing roller unit from crushed material obtained by crushing the raw material and transported by the conveying gas, and that is attached at a position where the journal head and the crushing roller are adjacent; and a blocking portion that blocks an area above the protective member; and the method comprises an installation step of attaching a blocking portion (28) that blocks an area above the protective member to prevent crushed material obtained by crushing the raw material from entering a space (S1) formed between the crushing roller and the protective member.

In accordance with the protective device installation method according to one aspect of the present disclosure, the carrier gas blown out from the outlet transports the pulverized material inside the housing upward. The pulverized material transported upward from the outlet toward the crushing roller collides with the protective member, preventing the crushing roller from being worn down by collisions with the pulverized material.

The protective member attached to the crushing roller unit surrounds the lower portion of the journal shaft where the journal head and crushing roller are adjacent, but the upper portion of the journal shaft is open. Therefore, if the upper portion of the journal shaft remains open, crushed material blown up onto the upper portion of the journal shaft falls and enters the space formed between the crushing roller and the protective member. Crushed material with a particle size smaller than the gap formed between the crushing roller and the protective member falls downward through the gap and does not accumulate on the inner surface of the protective member. On the other hand, crushed material with a particle size larger than the gap formed between the crushing roller and the protective member does not fall downward through the gap and accumulates on the inner surface of the protective member.

In a protective device installation method according to one aspect of the present disclosure, during the installation process, a blocking portion attached to the crushing roller unit blocks the area above the protective member to prevent crushed material from entering the space formed between the crushing roller and the protective member. Therefore, even if crushed material with a particle size larger than the gap formed between the crushing roller and the protective member falls from above the protective member, the blocking portion prevents it from entering the space. This prevents crushed material from accumulating in the space formed between the protective member and the crushing roller, which can cause wear on the inner surfaces of the crushing roller and the protective member.

10. Crusher (crushing device)
11 Housing 13 Crushing table 20, 20B, 20C, 20D Crushing roller unit 20J Roller journal portion 21 Crushing roller 21a Roller housing 21b Shaft portion 21c Roller main body portion 22 Journal shaft 23 Journal head 27 Roller journal protector (protective device)
27a Apron-shaped panel 27b Shield (protective member)
27b1 Planar part 27b2 Through hole 27bA Base end 27bB Tip part 27bC Lower region 27c Ceramic style 28, 28A, 28B Closing part 28a, 28Aa, 28Ba First part 28c, 28Ac Upper surface 28b, 28Ab, 28Bb Second part 28Bc Support member 28Bd Through hole 29 Intrusion prevention member AD Axial direction C1 Central axis CL1 Gap HD Horizontal direction L1 First distance L2 Second distance LF Coarse grain PF Fine grain RD Rotation direction S1 Narrow space S2 Internal space T1, T2 Thickness Y1 Axis α, β Inclination angle θ Angle

Claims (10)

A protection device attached to a crushing device that crushes raw materials,
The grinding device is
A grinding table;
a crushing roller unit that crushes the raw material supplied from the raw material supply unit to the crushing table between the raw material supply unit and the crushing table;
an outlet that is provided on the outer periphery of the rotary table and that blows out a carrier gas upward;
The crushing roller unit includes:
a journal head attached to the housing;
a journal shaft supported by the journal head and extending along an axis;
a crushing roller attached to the journal shaft so as to be rotatable about the axis;
a protective member that surrounds a lower portion of the journal shaft at a position where the journal head and the crushing roller are adjacent to each other and protects the crushing roller unit from crushed material obtained by crushing the raw material and transported by the carrier gas;
a blocking portion that blocks an area above the protective member to prevent the crushed material from entering a space formed between the crushing roller and the protective member ,
The blocking portion is a plate-shaped member and is fixed to the protective member . the protection member is disposed at a first distance from the crushing roller;
the blocking portion is disposed at a second distance from the crushing roller,
The protection device of claim 1 , wherein the second distance is less than the first distance. A protective device as described in claim 1 or claim 2, wherein the blocking portion has an upper surface formed to extend parallel to the axis. A protective device as described in claim 1 or claim 2, wherein the blocking portion has an upper surface that is inclined downward from the crushing roller toward the journal head relative to the axis. A protective device as described in claim 1 or claim 2, wherein the blocking portion has an upper surface that slopes downward from the inner periphery toward the outer periphery in a horizontal direction perpendicular to the axis. A protection device attached to a crushing device that crushes raw materials,
The grinding device is
A grinding table;
a crushing roller unit that crushes the raw material supplied from the raw material supply unit to the crushing table between the raw material supply unit and the crushing table;
an outlet provided on the outer periphery of the rotary table for blowing out a carrier gas upward;
The crushing roller unit includes:
a journal head attached to the housing;
a journal shaft supported by the journal head and extending along an axis;
a crushing roller attached to the journal shaft so as to be rotatable about the axis;
a protective member that surrounds a lower portion of the journal shaft at a position where the journal head and the crushing roller are adjacent to each other and protects the crushing roller unit from crushed material obtained by crushing the raw material and transported by the carrier gas;
a blocking portion that blocks an area above the protective member to prevent the crushed material from entering a space formed between the crushing roller and the protective member,
The blocking portion is fixed to the protective member so as to be movable in a direction along the axis and/or a direction perpendicular to the axis. the blocking portion is fixed to an upper end of the protection member,
The protection device according to claim 1 , further comprising a support member arranged to contact both a lower surface of the blocking portion and a surface of the protection member facing the space. The protection device according to any one of claims 1 to 7 , wherein the thickness of the protection device at a position close to the crushing roller is greater than the thickness of other positions. A protection device according to any one of claims 1 to 8 ;
A grinding table;
a crushing roller unit that crushes the raw material supplied from the raw material supply unit to the crushing table between the raw material supply unit and the crushing table;
an outlet that is provided on the outer periphery of the rotary table and that blows out a carrier gas upward;
The crushing roller unit includes:
a journal head attached to the housing;
a journal shaft supported by the journal head and extending along an axis;
a crushing roller attached to the journal shaft so as to be rotatable about the axis. A method for attaching a protection device to a crushing device that crushes raw materials, comprising:
The grinding device is
A grinding table;
a crushing roller unit that crushes the raw material supplied from the raw material supply unit to the crushing table between the raw material supply unit and the crushing table;
an outlet provided on the outer periphery of the rotary table for blowing out a carrier gas upward;
The crushing roller unit includes:
a journal head attached to the housing;
a journal shaft supported by the journal head and extending along an axis;
a crushing roller attached to the journal shaft so as to be rotatable about the axis;
The protection device comprises:
a protective member that surrounds a lower portion of the journal shaft to protect the crushing roller unit from crushed material obtained by crushing the raw material transported by the carrier gas, and that is attached at a position adjacent to the journal head and the crushing roller;
a plate-shaped blocking portion that blocks an area above the protective member,
and an installation step of attaching the blocking portion to the protective member to prevent crushed material from entering the space formed between the crushing roller and the protective member.