Grinding rolls and grain polishing machines

Abstract

In the process of milling raw grains as they flow from one end of a grinding roll to the other end, the raw grains are milled efficiently. [Solution] The grinding roll 15 comprises long segments 24, 25 that extend in the direction of the roll axis and are arranged in a large number along the outer circumference of the roll. The segments 24, 25 include coarse segments 24 with a large surface roughness and fine segments 25 with a small surface roughness. The coarse segments 24 and fine segments 25 are arranged alternately in the circumferential direction of the roll. The ends of the coarse segments 24 and fine segments 25 are constrained by roll end members 26.

Description

Technical Field

[0001] The present invention relates to a grinding roll attached to a grinding type rice milling machine.

Background Art

[0002] As a grinding type rice milling machine such as a rice milling machine for polishing brown rice, a vertical rice milling machine is known. In this machine, brown rice comes into frictional contact with the outer peripheral surface of a cylindrical grindstone called a grinding roll, and the surface of the brown rice is ground. For example, the vertical rice milling machine described in Japanese Patent Application Laid-Open No. 63-302957 (Patent Document 1) includes a friction roll and a grinding roll arranged in series as two types of grinding rolls having different friction coefficients on the cylindrical surface.

[0003] Also, in the rice milling roll of the vertical rice milling machine described in Japanese Patent Publication No. 02-049132 (Patent Document 2), two friction roll pieces and two grinding roll pieces formed in strip shapes are arranged on the side surface of a roll core material having an octagonal cross section at intervals of 90 degrees in the circumferential direction. Between these roll pieces, four roll pressing pieces formed in strip shapes are screwed, and the roll pieces are pressed and fixed from the outer periphery of the roll by the roll pressing pieces.

[0004] In the vertical rice milling machines of Patent Document 1 and Patent Document 2, brown rice is milled while flowing down from above the roll.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the inventors have found that there are areas for further improvement in the conventional vertical rice milling machines described above. Specifically, in the vertical rice milling machine described in Patent Document 1, the raw material, brown rice grains, flow down easily in the upper region of the grinding rolls, and the pressure acting on the raw material grains (brown rice) is low, so the grinding action is substantially small. On the other hand, the flowing raw material grains remain in the lower region of the grinding rolls, and the pressure acting on the raw material grains is high, so they are substantially subjected to a large grinding action. Therefore, there is a problem that the grinding action is not efficiently performed throughout the entire flow from the upper region to the lower region of the grinding rolls.

[0007] Furthermore, the rice milling roll described in Patent Document 2 has the problem that the grinding action is not performed efficiently because there are only four roll pieces of the two types, and in a roll with a roughly octagonal cross-section, four roll holders that do not contribute to rice milling occupy half of the eight sides of the roll.

[0008] In view of the above circumstances, the present invention aims to provide a grinding roll that can efficiently mill raw grains such as brown rice and bran-covered wheat. [Means for solving the problem]

[0009] For this purpose, the grinding roll according to the present invention comprises long segments extending in the direction of the roll axis and arranged in a large number along the outer circumference of the roll, the large number of segments including coarse segments with a large surface roughness and fine segments with a small surface roughness, the coarse segments and fine segments arranged alternately in the circumferential direction of the roll, and the ends of the coarse segments and fine segments are constrained by a roll end member or the inner diameter side is constrained by a roll core material.

[0010] According to this invention, since coarse and fine segments are arranged alternately in a large number of places in the circumferential direction, the scratching action that damages the surface of the raw grain and the peeling action that removes the surface from the damaged raw grain are performed many times during one rotation of the roll. Therefore, the raw grain can be milled efficiently in the process of milling, where the raw grain flows from one end of the grinding roll to the other end. In addition, the member that holds the segments from the outer circumference of the roll, as used in Patent Document 2, is not required, and the segments can be arranged at high density over the entire circumference of the roll, so there is no wasted area on the outer circumference of the roll, and the raw grain can be milled efficiently.

[0011] In one aspect of the present invention, the coarse segment and the fine segment are columnar bodies. In this aspect, all sides of the columnar body are used as grinding surfaces, and one of these sides is set on the outer circumference of the roll, thereby the grinding roll performs the aforementioned scratching and peeling action. When the outer circumference of the roll wears down due to long-term use, the restraint of the columnar body is temporarily released, the columnar body is rotated, and the unused side is set on the outer circumference of the roll, restoring the grinding roll to like-new condition. Therefore, it is cost-effective. In contrast, with the roll described in Patent Document 2, when the grinding roll piece or friction roll piece deteriorates due to wear, etc., it is necessary to replace the roll piece itself with a new one, which has the problem of increased effort and cost for parts replacement. In another aspect of the present invention, the segment may be a strip-shaped plate piece.

[0012] The columnar body is preferably a column with a polygonal cross-section. In a preferred aspect of the present invention, the columnar body is a triangular prism. With this aspect, almost the entire outer surface of the roll can be used as a grinding wheel surface.

[0013] In a more preferred aspect of the present invention, each of the columnar bodies has a through hole extending from one end to the other, and further comprises a shaft passed through the through hole, a first ring-shaped member that fixes the ends of the shafts together, and a second ring-shaped member that fixes the other ends of the shafts together, so that the columnar body can rotate around the shaft while the constraint by the roll end member or roll core material is temporarily released. In this aspect, since the columnar body can rotate around the shaft, the grinding roll can be easily restored by rotating the columnar body. In another aspect, the columnar body may not have a shaft and may be rotated and reassembled during maintenance of the grinding roll. The ring-shaped member may be in the shape of a ring itself, or it may be in a ring-like shape such as a disc.

[0014] The width dimension (circumferential dimension of the roll) of the coarse segment, which extends in the direction of the roll axis and has width in the direction of the roll circumference, is constant from one end in the direction of the roll to the other end. In another aspect of the present invention, the dimension of the coarse segment in the direction of the roll circumference increases from one end to the other in the direction of the roll axis, and the dimension of the fine segment in the direction of the roll circumference decreases from one end to the other in the direction of the roll axis. With this aspect, a minor scratching action can be mainly performed at one end in the direction of the roll axis, and a peeling action can be mainly performed at the other end in the direction of the roll axis. Therefore, raw grains flowing from one end in the direction of the roll axis to the other end in the direction of the roll axis can be milled efficiently.

[0015] The grain milling machine of the present invention comprises any of the above-described grinding rolls for grain milling machines. [Effects of the Invention]

[0016] Thus, according to the present invention, grain milling efficiency is improved, the time required for milling is shortened, and the grain milling machine can be made more compact. [Brief explanation of the drawing]

[0017] [Figure 1]This is a front view showing the appearance and internal structure of a grinding vertical rice polisher according to an embodiment of the present invention. [Figure 2] This is a perspective view showing a grinding roll according to an embodiment of the present invention. [Figure 3] This is an exploded perspective view showing the grinding roll of the same embodiment. [Figure 4] This is an explanatory view schematically showing how grain is ground by the grinding roll of the same embodiment. [Figure 5] This is a perspective view showing a grinding roll according to another embodiment of the present invention.

Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a front view showing the appearance and internal structure of a grinding vertical rice polisher according to an embodiment of the present invention. The rice polisher 10 is substantially cylindrical and is installed vertically. In FIG. 1, the cover member forming the outer peripheral surface of the substantially cylindrical shape is removed. The rice polisher 10 includes a raw material inlet 11 provided at one end of the substantially cylindrical shape, a resistance claw 13 detachably arranged on the outer periphery of the substantially cylindrical shape, a screen 14 attached to the outer peripheral side surface of the substantially cylindrical shape and fixed from the outer diameter side by the resistance claw 13, a cylindrical grinding roll 15 arranged on the inner diameter side of the screen 14, a lower structure 16 at the other end of the substantially cylindrical shape, a polished rice discharge port 17 provided on the front surface of the lower structure 16, and a drive shaft 18 installed at the center of the lower structure 16 and extending in the axial direction of the substantially cylindrical shape and coupled to the grinding roll 15.

[0019] The resistance claw 13 is provided with a fixing screw 21 with a dial and an adjusting screw 22. The fixing screw 21 fixes the resistance claw 13 so that it does not come off from the main body of the rice polisher 10. The adjusting screw 22 adjusts the gap between the grinding roll 15 on the inner diameter side and the resistance claw 13 on the outer diameter side. The resistance claw 13 is made of tool steel or the like and has high durability.

[0020] The screen 14 is a fine mesh member having a mesh smaller than the raw material grains and covers the outer peripheral surface of the grinding roll 15. Further, the screen 14 is made of stainless steel and has a certain degree of durability. In FIG. 1, only the front part of the cylindrical surfaces of the screen 14 and the grinding roll 15 is drawn, and the remaining cylindrical side edge parts are not shown.

[0021] Raw material grains such as brown rice and wheat grains with bran input from the raw material inlet 11, which have had their outer husks such as glumes removed and have the epidermis remaining, fill the gap between the grinding roll 15 on the inner diameter side and the resistance claws 13 on the outer diameter side. Further, the raw material grains fill the gap between the grinding roll 15 on the inner diameter side and the screen 14 on the outer diameter side. The former gap is smaller than the latter gap. These gaps constitute a cylindrical space.

[0022] While the grinding roll 15 rotates, the raw material grains are carried along and rotate in the circumferential direction of the grinding roll 15. When passing through the gap between the grinding roll 15 and the resistance claws 13, the epidermis such as bran is removed (polished). Further, the raw material grains flow downward while making many revolutions and are finally discharged from the polished grain discharge port 17 in a state where the polishing is completed.

[0023] Air is passed through the above-described cylindrical space. The air entrains powder debris such as the epidermis of bran generated during polishing, passes through the screen 14, and is discharged outside the cylindrical gap.

[0024] FIG. 2 is a perspective view showing the grinding roll 15 taken out, and some parts are shown by phantom lines for easy understanding. The grinding roll 15 has a large number of long segments extending in the axial direction. The segments include a coarse segment 24 with a large surface roughness and a fine segment 25 with a small surface roughness, and these segments 24, 25 are alternately arranged in the circumferential direction. Gaps C, C, C... are formed between adjacent segments 24, 25, 24, 25... in the circumferential direction. The dimension of the gap C is approximately the same as or smaller than the raw material grains. The above-described air W jets out from the gap C. Further, the segments 24, 25 extend from one end to the other end of the grinding roll 15. Accordingly, the gap C also extends细长ly from one end to the other end of the grinding roll 15.

[0025] The cross-sectional shape of the outer surface of the roll, as shown by cutting segments 24 and 25 at a cross-section including the central axis of the grinding roll 15, does not have a wavy or uneven surface like a grinding roll for sake rice, but rather extends linearly in the direction of the roll axis.

[0026] The material of segments 24 and 25 is, for example, a ceramic mainly composed of silicon carbide (SiC), specifically a vitrified grinding wheel. By appropriately selecting the abrasive grains contained in the vitrified grinding wheel, the coarse segment 24 and the fine segment 25 are made to the appropriate roughness. The roughness of the coarse segment 24 is selected from the range of #20 to #60. The roughness of the fine segment 25 is selected from the range of #70 to #120.

[0027] The circumferential arrangement of segments 24, 25, 24, 25... is constrained by the roll end members 26 and will not disintegrate during grain milling. The grinding roll 15 of this embodiment has roll end members 26, 26 at both axial ends. The roll end members 26 may be wheel-shaped, ring-shaped, or have other shapes. The roll end members 26 may also be connectable to the drive shaft 18 (Figure 1). The roll end members 26 constrain the segments 24, 25 so that they cannot move in the roll axial direction. The roll end members 26 also constrain the segments 24, 25 so that they cannot move in the roll radial direction.

[0028] In Figure 1, four grinding rolls 15 are arranged in series. The number of grinding rolls 15 arranged in series is not particularly limited. As a modified example not shown, the ratio of the axial dimension to the outer diameter of the grinding rolls 15 is not particularly limited.

[0029] The action of the grinding rolls in this embodiment will be explained in detail with reference to Figure 4. First, the raw grain G has fine scratches F made on its outer layer H by the coarse segment 24 (small scratching action on the left side of Figure 4), and smaller bran powder I is separated. The scratches F make it easier to remove the outer layer H from the raw grain G. Next, the raw grain G has its outer layer H removed by the fine segment 25 (peeling action on the right side of Figure 4), and larger bran scraps J are separated. Milling is completed when all of the outer layer H has been removed.

[0030] The high-speed rotation of the grinding roll 15 simultaneously achieves the aforementioned minor scratching and peeling effects at several points in the circumferential direction of the grinding roll 15. According to this embodiment, the raw grain is milled efficiently in a short time, and the yield is improved compared to conventional technology. In particular, high-speed milling is achieved by setting the circumferential speed of the outer surface of the grinding roll 15 in the range of 600 m / min to 1000 m / min, preferably in the range of 700 m / min to 900 m / min, and more preferably in the range of 750 m / min to 850 m / min. The pressure applied to the raw grain in the gap between the inner diameter grinding roll 15 and the outer diameter resistance claw 13 is 1 cm 2 The pressure is preferably in the range of over 0 gf and up to 50 gf per unit area, more preferably over 0 gf and up to 20 gf per unit area. By selecting such pressure and peripheral speed, the minor scratching and peeling effects targeted by the present invention are achieved.

[0031] Figure 3 is an exploded perspective view showing the grinding roll 15. The grinding roll 15 includes a pair of rings 26b, 26d and a rotation prevention member 26c as members that restrain the segments 24, 25.... Polygonal holes 29, 29 are formed in each ring 26b, 26d at equal intervals in the circumferential direction. The circumferential spacing of the polygonal holes 29, 29 corresponds to the cross-sectional dimensions and gap C of the segment 25. In this embodiment, the polygonal holes 29 are regular hexagons.

[0032] Each segment 24, 25 is a columnar body with a polygonal cross-section. In this embodiment, each segment 24, 25 is a columnar body with an equilateral triangular cross-section. Each side surface of such a triangular prism has a gently curved surface that bulges slightly. Each segment 24, 25 has a hole 27 that runs straight through in the axial direction from one end to the other. The hole 27 coincides with the center of the polygonal cross-section. A shaft 28 is passed through the hole 27. The shaft 28 is, for example, a shaft with a hexagonal cross-section, and both ends of the shaft 28 protrude from both ends of the segment 24 (25), respectively. One end of the shafts 28, 28.... fits into the polygonal holes 29, 29.... of one ring 26b. The other ends of the shafts 28, 28.... fit into the polygonal holes 29, 29.... of the other ring 26d. The grinding roll 15, assembled in this manner as a segment assembly, allows rotation around the shaft 28 of each segment 24, 25, etc., as shown by arrow A in Figure 3.

[0033] A rotation-preventing member 26c is provided at the central opening 15c of the grinding roll 15. The rotation-preventing member 26c is an arc-shaped member having teeth that protrude outward in the radial direction, such as a sprocket. These teeth are interposed between adjacent segments 24 and 25, thereby restraining each segment 24 and 25 from rotating.

[0034] The rotation prevention member 26c is removable and can be temporarily removed to rotate the columnar segments 24 and 25, thereby setting a new side surface of the columnar segment to the outer surface of the grinding roll 15. In this way, according to this embodiment, an expensive vitrified grinding wheel can be recycled as many times as there are sides of the columnar body. The shape of the rotation prevention member 26c is not particularly limited, but it is preferable that it be a member that can be divided in the circumferential direction of the roll for the convenience of removal and reinstallation. The rotation prevention member 26c may also be a cylindrical or columnar core material that passes through the central opening 15c of the grinding roll 15 and has an inner diameter side that holds the segments 24 and 25 in a non-rotatable manner.

[0035] The cross-section of hole 27 is circular, as shown on the left side of Figure 3. This allows segments 24 and 25 to rotate around shaft 28 as described above. Alternatively, as shown on the right side of Figure 3, a polygonal hole 27' with a polygonal cross-section may be provided in segment 25'. The polygonal hole 27' fits with shaft 28, which has a polygonal cross-section. In the modified example, by removing rings 26b and 26d from the end of shaft 28, a new side surface of the segment columnar body can be set on the outer surface of the grinding roll 15.

[0036] The grinding roll 15 of this embodiment includes numerous long segments 24, 25, 24, 25... extending in the direction of the roll axis and arranged along the outer circumference of the roll. These segments 24, 25 include coarse segments 24 with a large surface roughness and fine segments 25 with a small surface roughness. The coarse segments 24 and fine segments 25 are arranged alternately in the circumferential direction of the roll, and the ends of the coarse segments 24 and fine segments 25 are constrained by roll end members 26. The roll end members 26 are, for example, a pair of rings 26b, 26d and an anti-rotation member 26c. These numerous segments 24, 25 simultaneously perform the scratching and peeling actions shown in Figure 4, enabling efficient grain milling.

[0037] Furthermore, since the coarse segment 24 and fine segment 25 of this embodiment are columnar, the number of grinding wheels that can be regenerated is equal to the number of sides of the columnar body, which is advantageous in terms of cost.

[0038] Furthermore, since segments 24 and 25 in this embodiment are triangular prisms, the grinding wheel surface can be extended over the entire circumference of the grinding roll 15, allowing for efficient grain milling.

[0039] Furthermore, each of the segments 24, 25, 24, 25... (a number of columnar bodies) in this embodiment has through holes 27, 27, 27, 27... extending from one end to the other and passing through the center of the cross-section of the columnar body. The grinding roll 15 further includes shafts 28, 28, 28, 28... passed through each of the through holes 27, 27, 27, 27..., a ring 26b as a first ring-shaped member that fixes one end of each of the shafts 28, 28, 28, 28..., a ring 26 as a second ring-shaped member that fixes the other ends of each of the shafts 28, 28, 28, 28..., and a rotation prevention member 26c that restrains the rotation of each columnar body around the shaft 28. The rotation prevention member 26c is removable, and each columnar body can rotate around the shaft 28 while the restraint by the rotation prevention member 26c is temporarily released. As a result, the outer surface of the grinding roll 15 is quickly regenerated.

[0040] Next, other embodiments of the present invention will be described. Figure 5 is a perspective view showing another embodiment of the present invention. For the other embodiment, components common to the previously described embodiment are denoted by the same reference numerals and their description is omitted, while different components are described below. The grinding roll 32 of the other embodiment comprises a roll core material 33, a coarse segment 34, and a fine segment 35. The surface roughness of the coarse segment 34 and the fine segment 35 is equivalent to that of segments 24 and 25 in the previously described embodiment.

[0041] The roll core material 33 is cylindrical, with numerous segments 34 and 35 attached to its outer surface. Alternatively, the roll core material 33 is a resin mold, molded into a cylindrical shape with numerous segments 34 and 35. Gaps C are appropriately formed between adjacent segments 34 and 35 in the circumferential direction to allow air W to be ejected.

[0042] In the embodiment shown in Figure 5, segments 34 and 35 are triangular, specifically isosceles triangles, or isosceles trapezoids. Segments 34 and 35 also extend elongated in the direction of the roll axis from one end to the other of the grinding roll 32.

[0043] The surfaces of each segment 34, 35 are rounded cylindrical curved surfaces that conform to the outer surface of the grinding roll 32. Alternatively, the surfaces of each segment 34, 35 may be flat surfaces that roughly conform to the outer surface of the grinding roll 32.

[0044] In the embodiment shown in Figure 5, the coarse segments 34 are arranged alternately such that the base of the isosceles triangle of the coarse segments 34 is at one end in the roll axis direction, and the base of the isosceles triangle of the fine segments 35 is at the other end in the roll axis direction. Specifically, the coarse segments 34 are on top and the fine segments 35 are on the bottom.

[0045] According to the embodiment shown in Figure 5, the circumferential dimension of the coarse segment 34 decreases from one end to the other in the roll axis direction, while the circumferential dimension of the fine segment 35 increases from one end to the other in the roll axis direction. With one end facing upwards and the other downwards, the raw grains flowing down from the upper end in the roll axis direction of the grinding roll 32 are first subjected to numerous small scratches by the upper coarse segment 34 (small scratching action on the left side of Figure 4). Next, the outer layer is peeled off by the lower fine segment 35 (peeling action on the right side of Figure 4). This allows for more efficient milling than conventional techniques.

[0046] Although embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as the present invention, or within the equivalent scope. For example, some components may be extracted from one embodiment described above, and other components may be extracted from other embodiments described above, and these extracted components may be combined. [Industrial applicability]

[0047] This invention is advantageously utilized in food production facilities. [Explanation of Symbols]

[0048] 15 grinding rolls, 24 coarse segments, 25 fine segments, 26. Roll end members.

Claims

1. It has long segments that extend in the direction of the roll axis and are arranged in large numbers along the outer circumference of the roll, The segment includes a coarse segment with a large surface roughness and a fine segment with a small surface roughness, and the coarse segment and the fine segment are arranged alternately in the circumferential direction of the roll. A grinding roll for a grain mill, wherein the coarse segment and the fine segment are constrained at their ends by a roll end member, or their inner diameter side is constrained by a roll core material.

2. The grinding roll for a grain milling machine according to claim 1, wherein the coarse segment and the fine segment are columnar bodies.

3. The grinding roll for a grain milling machine according to claim 2, wherein the columnar body is a triangular prism.

4. Each of the numerous columnar bodies has a through hole formed therein that extends from one end to the other. A shaft passed through the aforementioned through hole, A first ring-shaped member that fixes one end of the shafts together, The system further comprises a second ring-shaped member that fixes the other ends of the aforementioned shafts together, The grinding roll for a grain milling machine according to claim 2, wherein the columnar body is rotatable about the shaft while the restraint by the roll end member or the roll core is temporarily released.

5. The dimensions of the coarse segment in the circumferential direction of the roll increase from one end to the other in the direction of the roll axis. The grinding roll for a grain milling machine according to claim 1, wherein the dimensions of the fine segments in the circumferential direction of the roll become smaller from one end to the other in the direction of the roll.

6. A grain milling machine comprising a grinding roll for a grain milling machine according to any one of claims 1 to 5.

Images