Shaftless screw conveying device

Abstract

To provide a non-shaft screw conveying device capable of reducing the number of times of maintenance and cleaning such as removing solid matter by opening an opening window for maintenance when clogged with the solid matter.SOLUTION: The non-shaft screw conveying device 1 includes a non-shaft screw blade 10, a trough 20 having a circular cross-section or a U-shaped cross-section and housing the non-shaft screw blade therein, and a first protruding part 60 extending above a rotation shaft of the non-shaft screw blade in parallel with the rotation shaft partially or over the entire length on an inner surface of the trough. A second protrusion (70) extending above the rotary shaft of the non-shaft screw blade in parallel to the rotary shaft at a position facing the first protrusion (60) and spaced apart from the first protrusion (60) by a predetermined interval, and a driving means (30) configured to drive the non-shaft screw blade, wherein a first interval (d1) between the first protrusion and an outer diameter end of the non-shaft screw blade is smaller than a second interval (d2) between the second protrusion and the outer diameter end of the non-shaft screw blade.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a shaftless screw conveying device for conveying liquids containing various solids, such as sewage. [Background technology]

[0002] Separation devices are known that separate screen residues, such as hair, paper, scraps of fabric, plastic, and food waste, from sewage. For example, the separation device disclosed in Patent Document 1 separates screen residues from sewage using a screw with a shaft that has screw blades attached to the screw shaft. The shaftless screw conveying device of Patent Document 2 is provided with a restraining portion that is arranged parallel to the rotation axis of the shaftless screw blade at a predetermined distance from the outer diameter end of the shaftless screw blade. When the shaftless screw blade rises up due to the load, this restraining portion allows the outer diameter end to come into contact with the restraining portion, thereby suppressing the rise. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-18020 [Patent Document 2] Japanese Patent Publication No. 2023-90283 Summary of the Invention [Problem to be solved by the invention]

[0004] When transporting sewage using a shaft screw, there was a problem of residue building up over time, causing clogging several times a day. When residue clogged the screw blades, they stopped rotating, making it impossible to transport sewage. Furthermore, the clogged residue could even damage the screw blades. For this reason, an opening had to be made in the trough housing the shaft screw, and the clogged residue had to be removed frequently by hand. However, maintenance such as removal work required interruptions to the transport of sewage, which reduced the efficiency of sewage transport. Furthermore, because it was sewage, there was the problem of a foul odor, making for a very poor working environment.

[0005] Even in conveying devices with shaftless screw blades, there are situations where the conveyed material rotates together and cannot be sent downstream. For this reason, in Patent Document 2, multiple flat bars are provided between the shaftless screw blades and the inner periphery of the trough.

[0006] The present invention provides a shaftless screw conveying device that can significantly reduce the number of maintenance cleaning operations, such as opening a maintenance opening window to remove solid matter when the device is clogged with solid matter. To provide a shaftless screw conveying device capable of suppressing co-rotation of conveyed objects by a method that does not use a flat bar. [Means for solving the problem]

[0007] The shaftless screw conveying device (1) of the present invention is A shaftless screw blade (10); a trough (20) having a circular or U-shaped cross section that accommodates the shaftless screw blade (10) therein; a first protrusion (60) extending partially or entirely above the rotation axis (O) of the shaftless screw blade (10) on the inner surface of the trough (20) and parallel to the rotation axis (O); a second protrusion (70) extending from the inner surface of the trough (20) above the rotation axis (O) of the shaftless screw blade (10), parallel to the rotation axis (O), and at a predetermined distance (d3) from the first protrusion (60) at a position opposite the first protrusion (60); a driving means (30) for driving the shaftless screw blade; Equipped with A first distance (d1) between the first protrusion (60) and the outer diameter end (103) of the shaftless screw blade (10) is smaller than a second distance (d2) between the second protrusion (70) and the outer diameter end (103) of the shaftless screw blade (10).

[0008] At a position within ±60 degrees from a vertical line (V) passing through the highest point (T) of the outer diameter end (103) of the shaftless screw blade (10) and the rotation axis (O), there is a first interval (d1) which is the shortest distance between the first protrusion (60) and the outer diameter end (103) of the shaftless screw blade (10), and there is a second interval (d2) which is the shortest distance between the second protrusion (70) and the outer diameter end (103) of the shaftless screw blade (10). For example, a first interval (d1) that is the shortest distance between the first protrusion (60) and the outer diameter end (103) of the shaftless screw blade (10) may be located within -60 degrees (within 60 degrees clockwise) from the vertical line (V), and a second interval (d2) that is the shortest distance between the second protrusion (70) and the outer diameter end (103) of the shaftless screw blade (10) may be located within +60 degrees (within 60 degrees counterclockwise) from the vertical line (V). For example, a second interval (d2) that is the shortest distance between the second protrusion (70) and the outer diameter end (103) of the shaftless screw blade (10) may be located within -60 degrees (within 60 degrees clockwise) from the vertical line (V), and a first interval (d1) that is the shortest distance between the first protrusion (60) and the outer diameter end (103) of the shaftless screw blade (10) may be located within +60 degrees (within 60 degrees counterclockwise) from the vertical line (V).

[0009] With this configuration, as the shaftless screw blade rotates, the material is sent from upstream to downstream in the conveying direction, from below the rotation axis to above the rotation axis, passing between the second protrusion and the outer diameter end of the shaftless screw blade (second gap).The material is then sent near the first protrusion, where it cannot pass through the narrow gap between the first protrusion and the outer diameter end of the shaftless screw blade (first gap) and hits the first protrusion, stopping.The material that has gathered between the first protrusion and the second protrusion above the rotation axis is then conveyed downstream in the conveying direction by the rotation of the shaftless screw blade. The material being conveyed below the rotation axis is also conveyed downstream in the conveying direction by the rotation of the shaftless screw blade. This allows the transported objects located below the rotation axis to be sent upward even partially and collected at the top for transport, thereby preventing clogging of the transported objects and co-rotation.

[0010] A liner (80) may be provided between the outer diameter end (103) of the shaftless screw blade (10) and the inner surface of the trough (20).

[0011] The shaftless screw blade (10) is clockwise with the flange (33) of the driving means (30) as its base end, and when the rotation shaft (O) rotates clockwise as viewed from the flange toward the blade tip (101), the transported material may be sent from the blade tip side (101) to the flange side (33). In this case, when the rotation axis (O) is viewed in a direction from the flange (33) toward the blade tip (101), the first protrusion (60) may be provided between the outer diameter end (103) of the shaftless screw blade (10) and the right inner surface (201) of the trough (20), and the second protrusion (70) may be provided between the outer diameter end (103) of the shaftless screw blade (10) and the left inner surface (202) of the trough (20).

[0012] With this configuration, the shaftless screw blade is clockwise, with the flange of the drive means as its base end, and when the rotating shaft rotates clockwise as viewed from the flange toward the blade tip, the transported material passes between the second protrusion and the outer diameter end of the shaftless screw blade (second gap), rotates clockwise, and is transported until it hits the first protrusion and stops. Any transported material that accumulates between the first protrusion and the second protrusion above the rotating shaft is transported downstream in the transport direction by the rotation of the shaftless screw blade. This prevents the transported material from clogging or rotating together.

[0013] The shaftless screw blade (10) is left-handed with the flange (33) of the driving means (30) as its base end, and when the rotation shaft (O) rotates left-handed as viewed in the direction from the flange (33) to the blade tip (101), the transported material may be sent from the blade tip side (101) to the flange side (33). In this case, when the rotation axis (O) is viewed in the direction from the flange (33) toward the blade tip (101), the first protrusion (60) may be provided between the outer diameter end (103) of the shaftless screw blade (10) and the left inner surface (202) of the trough (20), and the second protrusion (70) may be provided between the outer diameter end (103) of the shaftless screw blade (10) and the right inner surface (201) of the trough (20).

[0014] With this configuration, the shaftless screw blade is left-handed with the flange of the drive means as its base end, and when the rotating shaft rotates counterclockwise as viewed from the flange toward the blade tip, the transported object passes between the second protrusion and the outer diameter end of the shaftless screw blade (second gap), rotates counterclockwise, is transported, and comes to a stop when it hits the first protrusion. Any transported object that accumulates between the first protrusion and the second protrusion above the rotating shaft is transported downstream in the transport direction by the rotation of the shaftless screw blade. This prevents the transported object from clogging or rotating together.

[0015] The first distance (d1) may be 1 to 3 mm, and the second distance (d2) may be 4 to 15 mm. The second distance (d2) may be two to five times the first distance (d1). The first distance (d1) and the second distance (d2) are design dimensions with a tolerance of ±0.5 mm. During operation, the first distance (d1) or the second distance (d2) may partially become 0 mm.

[0016] This configuration can prevent clogging and circulation of solid matter such as sediment, and can transport sewage. In other words, the number of cleaning maintenance tasks can be reduced, and the burden on workers can be significantly reduced.

[0017] The inclination angle (α) of the shaftless screw conveying device (1) is, for example, from 0 degrees (horizontal) to 50 degrees. The inclination angle (α) may be determined based on the supply height to the downstream device, the allowable installation space, etc.

[0018] The trough (20) may be made of, for example, reinforced plastic or metal, and is preferably made of, for example, stainless steel. The trough (20) may be configured to have a first part and a second part along the longitudinal direction.

[0019] The trough 20 is shaped to fit the inner surface of the casing and is made of, for example, reinforced plastic or metal, preferably stainless steel.

[0020] The driving means (30) is composed of a motor, a speed change gear, a connecting means, a control device, a power supply, etc. The driving means (30) preferably rotates the shaftless screw blade at a rotation speed of, for example, 3 rpm to 15 rpm. When the motor of the drive means (30) and the like are installed above the shaftless screw blade (10), there is no need to provide a bearing below it as in a shafted screw conveyor, so there is no need to worry about bearing damage. Also, even if the motor of the drive means (30) and the like are installed below it, there is no need to worry about conveyed objects getting in because of the high level of sealing (sealed structure). The driving means (30) preferably rotates the shaftless screw blade (10) at a rotation speed of 5 to 17 rpm, more preferably 8 to 15 rpm. Within the above rotation speed range, it is preferable that the rotation speed be decreased as the outer diameter (80 mm to 600 mm) of the shaftless screw blade (10) increases, and that the rotation speed be increased as the outer diameter decreases.

[0021] The materials to be transported include sewage, pulp water, edible oil, fruit juice drinks, chemically treated water, etc., which contain solids.

[0022] The total length (L) of the shaftless screw blade 10 is, for example, 2 m to 10 m. The outer diameter (r1) of the shaftless screw blade 10 is, for example, 100 mm to 600 mm. The pitch (p) of the shaftless screw blade 10 is, for example, 75 mm to 600 mm. The inner diameter (r2) of the shaftless screw blade 10 is, for example, 20 mm to 220 mm. The thickness (t) of the shaftless screw blade 10 is, for example, 10 mm to 35 mm. The blade width (w or w×2) of the shaftless screw blade is, for example, 30 mm to 140 mm. A shaftless screw blade is made by welding together 3m to 10m long components to form a continuous screw blade.

[0023] The sum of the inner diameter (r2) and the blade width (w) is the outer diameter (r1). Alternatively, (r2 + w ≈ r1), where r1 is smaller if w is inclined and not extending perpendicularly from the radial direction. In another embodiment, the outer diameter (r1) is the sum of the inner diameter (r2) and twice the blade width (w). Alternatively, (r2 + w × 2 ≈ r1), where r1 is smaller if w is inclined and not extending perpendicularly from the radial direction. Two blades may be configured as one blade, with the outer width surface of the second blade, which has a smaller outer diameter, fixed to the inner width surface of the first blade, which has a larger outer diameter (see FIG. 2).

[0024] The relationship between the outer diameter (r1) of the shaftless screw blade and the pitch (p) of the shaftless screw blade is such that the pitch (p) is 0.5 to 1.5 times the outer diameter (r1), and preferably 1.0 times.

[0025] The shaftless screw blade (10) may have, for example, a rectangular cross section. As the outer diameter (r1) of the screw blade increases, the blade width (w) and blade thickness (t) are set to larger values. The total length (L), screw blade outer diameter (r1), pitch (p), blade inner diameter (r2), and blade width (w) are set according to the physical properties of the material being conveyed and / or the conveyance amount per unit time (screw rotation speed) and the degree of mixing.

[0026] Examples of steel materials that can be used as raw materials for shaftless screw blades include general structural rolled steel materials (SS330, SS400, SS490, SS540, etc.), cold-rolled steel plates (SPCC, SPCD, SPCE, SPCF, SPCG, etc.), carbon steel materials (S25C, S30C, S35C, S45C, S50C, S55C, etc.), hot- or cold-rolled stainless steel plates (SUS304, SUS316, SUS430, SUS410, etc.), wear-resistant steel plates (HARDOX (registered trademark) from Swedish Steel Corporation, EVERHARD (registered trademark) from JFE Steel Corporation, etc.), high-tensile steel plates (SM570, SMA570W, etc.), and TMCP-type high-tensile steel plates (SM570TMC, SMA570WTMC, etc.).

[0027] The steel material used as the raw material for the shaftless screw blade is preferably a steel material with higher strength (higher tensile strength) than general structural rolled steel (SS400). This is preferable from the standpoint of wear resistance and durability. In the case of SS400, the overall length of the screw blade shrinks by about 10% to 15% compared to its initial value after long-term use (for example, 6 months, 7 hours / day). However, stainless steel plates with higher strength (higher tensile strength) than SS400, such as wear-resistant steel plates (HARDOX (registered trademark) from Swedish Steel Corporation and EVERHARD (registered trademark) from JFE Steel Corporation), shrink to an extremely small extent.

[0028] [Effects of the invention] It is possible to provide a shaftless screw conveying device that can reduce the number of maintenance cleaning operations, such as opening a maintenance opening window to remove solid matter when the device is clogged with solid matter. A shaftless screw conveying device has been provided that can suppress co-rotation of conveyed objects without using a flat bar. [Brief explanation of the drawings]

[0029] [Figure 1A] FIG. 1 is a schematic diagram of a shaftless screw conveying device. [Figure 1B] FIG. 2 is a plan view of the shaftless screw conveying device. [Figure 2] FIG. 2 is a diagram schematically showing a cross section taken along the line AA in FIGS. 1A and 1B. [Figure 3] FIG. 10 is a schematic diagram illustrating the arrangement of a shaftless screw blade, a first protrusion, and a second protrusion in another embodiment. [Figure 4] 10 is a schematic diagram illustrating a first protrusion and a second protrusion in another embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0030] (Embodiment 1) The shaftless screw conveying device 1 of this embodiment will be described with reference to the drawings. As shown in Figures 1A and 1B, the shaftless screw conveying device 1 includes a shaftless screw blade 10, a trough 20 with a U-shaped cross section that houses the shaftless screw blade 10 therein, and a drive means 30 that drives the shaftless screw blade 10. Note that for convenience of explanation, Figure 1A shows the shaftless screw blade 10, which is located inside the trough 20 and cannot be seen from the outside of the shaftless screw conveying device 1. 1A, the shaftless screw conveying device 1 includes a rotating shaft 31 connected to a driving means 30 and a flange 33 fixed to the rotating shaft 31. The shaftless screw blade 10 is fixed to the rotating shaft 31 and the flange 33.

[0031] 1A, the inclination angle α of the shaftless screw conveying device 1 from the horizontal is 30 degrees. An inlet 40 for introducing the material to be conveyed is provided on the low-position side of the inclined trough 20 (the side of one end 101 of the shaftless screw blade 10), and an outlet 50 for discharging the material to be conveyed is provided on the high-position side (the side of the other end 102 of the shaftless screw blade 10). The material to be conveyed is conveyed from the low-position side to the high-position side of the trough 20. For example, the shaftless screw conveying device 1 may be installed in a sewage treatment plant or the like. A dust collector (not shown) may be arranged upstream of the inlet 40 in the conveying direction, and sewage from which dust, garbage, fallen leaves, earth and sand have been removed by the dust collector may be introduced into the inlet 40. The shaftless screw conveying device 1 may convey screened residue contained in the sewage to the discharge outlet 50. A screened residue crusher (not shown) may be arranged downstream of the discharge outlet 50 in the conveying direction, and the screened residue may be discharged from the discharge outlet 50 toward the screened residue crusher. The sewage from which the screened residue has been separated may be discharged from drainage pipes 51 and 52.

[0032] Figure 2 is a diagram schematically showing the AA cross section of Figures 1A and 1B. As shown in Figures 1A, 1B, and 2, the shaftless screw conveying device 1 is provided with a first protrusion 60 and a second protrusion 70 on the inner surface of the trough 20, which protrude toward the inside of the trough 20 (the shaftless screw blade 10 side). Note that for convenience of explanation, Figures 1A and 1B show the first protrusion 60 and the second protrusion 70, which are located inside the trough 20 and cannot be seen from the outside of the shaftless screw conveying device 1. As shown in FIG. 2, the first protrusion 60 and the second protrusion 70 are provided on the inner surface of the trough 20 so as to extend above the rotation axis O of the shaftless screw blade 10 and in parallel therewith. 1A, the first protrusion 60 and the second protrusion 70 extend from a portion of the trough 20 where the inlet 40 is provided to a portion where the outlet 50 is provided. The first protrusion 60 and the second protrusion 70 may extend over another portion of the trough 20 or over the entire length of the trough 20.

[0033] As shown in FIG. 2, the first protrusion 60 extends from the outer diameter end 103 of the shaftless screw blade 10 at a first distance (d1). The first distance (d1) is the shortest distance between the outer diameter end 103 of the shaftless screw blade 10 and the first protrusion 60. The second protrusion 70 extends from the outer diameter end 103 of the shaftless screw blade 10 at a second distance (d2) and a third distance (d3) from the first protrusion 60. The second distance (d2) is the shortest distance between the outer diameter end 103 of the shaftless screw blade 10 and the second protrusion 70. The first distance (d1) is smaller than the second distance (d2). The first protrusion 60 is provided so that a first interval (d1) is at an angle β from a vertical line V passing through the rotation axis O and the highest point T of the outer diameter end 103 of the shaftless screw blade 10. The second protrusion 70 is provided so that a second interval (d2) is at an angle γ from a vertical line V passing through the rotation axis O and the highest point T of the outer diameter end 103 of the shaftless screw blade 10. For example, angle β may be +10 degrees to +60 degrees (10 to 60 degrees clockwise in the positive direction). Angle γ may be -5 degrees to -45 degrees (-5 degrees to -45 degrees clockwise in the negative direction). The absolute value of angle β may be equal to or greater than the absolute value of angle γ. The smaller the absolute value of angle γ, the easier it is to send the transported object to the upper space. The larger the absolute value of angle β, the larger the volume of the upper space can be. The amount of transported object that can be sent to the upper space can be adjusted by setting angles β and γ. When the second interval (d2) is located higher on the trough 20 (closer to the uppermost point T of the outer diameter end 103 of the shaftless screw blade 10) than the first interval (d1), solid matter in the conveyed material is likely to be conveyed from the lower side of the trough 20 to the upper side of the trough 20 through the second interval (d2) as the shaftless screw blade 10 rotates. That is, it is possible to prevent solid matter in the conveyed material from being unable to pass through the second interval (d2) and accumulating below the trough 20. Furthermore, because the first interval (d1) is located lower on the trough 20 than the second interval (d2), a wider area is created between the first protrusion 60 and the outer diameter end 103 of the shaftless screw blade 10, and solid matter that has passed through the second interval (d2) is likely to accumulate.

[0034] In this embodiment, the first protrusion 60 and the second protrusion 70 are angles with an L-shaped cross section. For example, the first distance (d1) may be 1 to 3 mm, and the second distance (d2) may be 4 to 15 mm. The third distance (d3) may be 8 mm to 30 mm. The second distance (d2) may be two to five times the first distance (d1). The first distance (d1) and the second distance (d2) are design dimensions, with a tolerance of ±0.5 mm. During operation, the first distance (d1) or the second distance (d2) may partially become 0 mm.

[0035] 1A, the shaftless screw blade 10 is clockwise, with the flange 33 of the drive means 30 as its base end. The shaftless screw blade 10 rotates clockwise when the rotation axis O (see FIG. 2) is viewed in the direction from the flange 33 to the blade tip (one end 101 of the shaftless screw blade 10). The conveyed material is sent from the blade tip side (one end 101 side of the shaftless screw blade 10) to the flange 33 side. As shown in Figure 2, the first protrusion 60 is provided between the outer diameter end 103 of the shaftless screw blade 10 and the right inner surface 201 of the trough 20, and the second protrusion 70 is provided between the outer diameter end 103 of the shaftless screw blade 10 and the left inner surface 202 of the trough 20.

[0036] When the conveyed material is a liquid containing solids, the solids rotate and move from the bottom of the trough 20 toward the top of the trough 20 as the shaftless screw blade 10 rotates clockwise. The solids pass through the wide gap (second distance d2) between the second protrusion 70 and the outer diameter end 103 of the shaftless screw blade 10, but cannot pass through the narrow gap (first distance d1) between the first protrusion 60 and the outer diameter end 103 of the shaftless screw blade 10, and come into contact with and remain on the first protrusion 60. The solids remain and accumulate above the first protrusion 60 and the outer diameter end 103 of the shaftless screw blade 10, while being conveyed downstream in the conveying direction. In this way, the solids can be prevented from rotating together with the shaftless screw blade 10, thereby preventing the solids from becoming entangled in the shaftless screw blade 10 and causing clogging. For example, if the material being transported is sewage containing screen residue, the number of maintenance cleaning operations, such as removing solid matter, can be reduced by opening a maintenance opening provided in the trough 20. Manual screen residue removal work is unsanitary, and there has been the problem of difficulty in securing workers due to the poor working environment, but this problem can be solved by reducing the number of maintenance cleaning operations. In this embodiment, the first protruding portion 60 and the second protruding portion 70 continue from the inlet 40 to the outlet 50, so that solid matter in the conveyed object is conveyed appropriately from the inlet 40 to the outlet 50.

[0037] 2, the shaftless screw conveying device 1 may include a liner 80 disposed between the outer diameter end 103 of the shaftless screw blade 10 and the inner surface of the trough 20. The shaftless screw conveying device 1 may include a trough cover 90.

[0038] In this embodiment, The total length (L) of the shaftless screw blade 10 is, for example, 5 m to 6 m. The outer diameter (r1) of the shaftless screw blade 10 is, for example, 300 mm to 400 mm. The pitch (p) of the shaftless screw blade 10 is, for example, 200 mm to 300 mm. The inner diameter (r2) of the shaftless screw blade 10 is, for example, 20 mm to 120 mm. The thickness (t) of the shaftless screw blade 10 is, for example, 25 mm. The blade width (w) of the shaftless screw blade 10 is, for example, 30 mm to 140 mm.

[0039] (Embodiment 2) The following description of embodiment 2 will focus on the differences from embodiment 1. Note that the same components as those in embodiment 1 are given the same reference numerals, and the description thereof will be omitted. Although not shown in the drawings, the shaftless screw blade 10a of the second embodiment is left-handed, with the flange 33 of the drive means 30 as its base end. The shaftless screw blade 10a rotates left-handed when the rotation axis O is viewed in the direction from the flange 33 to the blade tip (one end of the shaftless screw blade 10a). The conveyed material is sent from the blade tip side (one end side of the shaftless screw blade 10a) to the flange 33 side. As shown in Figure 3, the first protrusion 60 is provided between the outer diameter end 103a of the shaftless screw blade 10a and the left inner surface 202 of the trough 20, and the second protrusion 70 is provided between the outer diameter end 103a of the shaftless screw blade 10a and the right inner surface 201 of the trough 20.

[0040] The first protrusion 60 is provided so that the first spacing (d1) is at an angle β from a vertical line V passing through the rotation axis O and the highest point T of the outer diameter end 103a of the shaftless screw blade 10a. The second protrusion 70 is provided so that the second spacing (d2) is at an angle γ from a vertical line V passing through the rotation axis O and the highest point T of the outer diameter end 103a of the shaftless screw blade 10a. For example, angle β may be +10 degrees to +60 degrees (10 to 60 degrees in the positive direction counterclockwise). Angle γ may be -5 degrees to -45 degrees (-5 to -45 degrees in the negative direction counterclockwise). The absolute value of angle β may be equal to or greater than the absolute value of angle γ. The smaller the absolute value of angle γ, the easier it is to send the transported object to the upper space. The larger the absolute value of angle β, the larger the volume of the upper space can be. The amount of transported object that can be sent to the upper space can be adjusted by setting angles β and γ. When the second interval (d2) is located higher on the trough 20 (closer to the uppermost point T of the outer diameter end 103 of the shaftless screw blade 10) than the first interval (d1), solid matter in the conveyed material is likely to be conveyed from the lower side of the trough 20 to the upper side of the trough 20 through the second interval (d2) as the shaftless screw blade 10a rotates. That is, it is possible to prevent solid matter in the conveyed material from being unable to pass through the second interval (d2) and accumulating below the trough 20. Furthermore, because the first interval (d1) is located lower on the trough 20 than the second interval (d2), a wider area is created between the first protrusion 60 and the outer diameter end 103a of the shaftless screw blade 10a, and solid matter that has passed through the second interval (d2) is likely to accumulate.

[0041] In the shaftless screw conveying device of the second embodiment, solid matter in the conveyed material passes through the wide gap (second distance d2) between the second protrusion 70 and the outer diameter end 103a of the shaftless screw blade 10a, but cannot pass through the narrow gap (first distance d1) between the first protrusion 60 and the outer diameter end 103a of the shaftless screw blade 10a, and instead hits and remains on the first protrusion 60. The solid matter remains and accumulates above the first protrusion 60 and the outer diameter end 103a of the shaftless screw blade 10a, and is conveyed downstream in the conveying direction. This prevents clogging and co-rotation of the conveyed material.

[0042] (Another embodiment) (1) The inclination angle α from the horizontal may be greater than 30 degrees and may be as small as 50 degrees. The larger the inclination angle, the narrower the pitch (p) of the shaftless screw blade 10 may be. By narrowing the pitch (p) of the shaftless screw blade 10, it is possible to prevent the transported material from falling upstream even if the inclination angle is large. Horizontal installation without inclination is also possible. (2) The cross section of the trough is not limited to a U-shape, but may be circular. (3) As shown in Fig. 4, the first protrusion and the second protrusion may be flat bars with a rectangular cross section (first protrusion 60b, second protrusion 70b). Although not shown, the first protrusion and the second protrusion may have a triangular, trapezoidal, or parallelogram cross section. The first protrusion and the second protrusion may have a semi-elliptical or semi-circular cross section.

[0043] <Example> The shaftless screw conveying device 1 of the first embodiment was installed in a sewage treatment plant. Total length of shaftless screw blade 10 (L): 5.448m Outer diameter of shaftless screw blade 10 (r1): 377 mm Pitch of 10 non-axial screw blades (p): 251 mm Inner diameter of shaftless screw blade 10 (r2): 93 mm Thickness of shaftless screw blade 10 (t): 25 mm Shaftless screw blade 10 blade width (w): 140 mm Inclination angle from the plane of the conveyor: 30 degrees The system was able to transport the screen residue contained in the sewage, and was able to continue transporting the screen residue for at least three months without the need for manual removal work. [Explanation of symbols]

[0044] 1. Shaftless screw conveyor 10, 10a Shaftless screw blade 103, 103a Outer diameter end 20 Trough 30 Driving means 60, 60b 1st protrusion 70, 70b 2nd protrusion

Claims

1. A shaftless screw blade; a trough having a circular or U-shaped cross section that accommodates the shaftless screw blade therein; a first protrusion provided on the inner surface of the trough above the rotation axis of the shaftless screw blade and extending partially or entirely in parallel with the rotation axis; a second protrusion extending from the inner surface of the trough above the rotation axis of the shaftless screw blade, parallel to the rotation axis, and spaced a predetermined distance from the first protrusion at a position opposite the first protrusion; a driving means for driving the shaftless screw blade; Equipped with a first distance (d1) between the first protrusion and the outer diameter end of the shaftless screw blade is smaller than a second distance (d2) between the second protrusion and the outer diameter end of the shaftless screw blade; Shaftless screw conveying device.

2. 2. The shaftless screw conveying device according to claim 1, wherein the shaftless screw blade is right-handed with the flange of the driving means as its base end, and when the rotating shaft rotates clockwise as viewed in the direction from the flange toward the blade tip, the first protrusion is provided between the outer diameter end of the shaftless screw blade and the right inner surface of the trough, and the second protrusion is provided between the outer diameter end of the shaftless screw blade and the left inner surface of the trough as viewed in the direction from the flange toward the blade tip.

3. 2. The shaftless screw conveying device according to claim 1, wherein when the shaftless screw blade is left-handed with the flange of the driving means as its base end and the rotating shaft rotates counterclockwise when viewed in the direction from the flange toward the blade tip, the first protrusion is provided between the outer diameter end of the shaftless screw blade and the left inner surface of the trough, and the second protrusion is provided between the outer diameter end of the shaftless screw blade and the right inner surface of the trough when viewed in the direction from the flange toward the blade tip.

4. The shaftless screw conveying device according to any one of claims 1 to 3, wherein the first distance (d1) is 1 to 3 mm, and the second distance (d2) is 4 to 15 mm.

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