Concentration / dehydration machine

Abstract

To provide a concentration / dehydration machine capable of achieving high dehydration performance while making full use of a basic configuration for existing concentration / dehydration machines.SOLUTION: A concentration / dehydration machine is composed of: a notch disposed on a tank surface of a raw material storage tank, which rotatably guides a rotary shaft 21 of a dehydration drum 19B and is inserted into; a support frame extending in a direction orthogonal to the rotary shaft 21, equipped with a bearing 22 located outside the raw material storage tank to rotatably support the rotary shaft 21; an air spring 8 disposed on one side in an extending direction across the rotary shaft 21 of the support frame; and a swing part 7 disposed on the other side. As the air spring 8 expands and contracts, the rotary shaft 21 is shifted in a longitudinal direction within the notch. The air spring 8 directly lifts and supports the dehydration drum 19B, thereby reducing the load applied to the air spring 8. The air spring contracts when receiving force in a contracting direction, but returns to a maximum lifting state once the force is removed. Even when the thickness of a raw material mat delivered between barrel parts 20 fluctuates, it is consistently compressed in a high-pressure equilibrium state and dehydrated to a high concentration at once.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a concentrating and dewatering machine that can be used to concentrate and dewater various types of pulp. [Background technology]

[0002] The concentrating dehydrator shown in Patent Document 1 has a raw material inlet at the bottom of a raw material storage tank and a raw material outlet at the top. Two parallel dehydration drums are installed inside the raw material storage tank. The two dehydration drums are made of a material with water holes, such as perforated metal, and wire mesh. The two dehydration drums rotate counterclockwise, moving upward along their tangent line. The dehydration drum on the raw material outlet side rotates in a fixed position, and a fine-mesh wire mesh is attached to its outer periphery. The dehydration drum on the opposite side tilts around its lower fulcrum, supported by an air spring. A coarse-mesh wire mesh is attached to its outer periphery. Both end faces of the two dehydration drums are open, and these openings connect the interiors of the dehydration drums to a drainage port on the side of the raw material storage tank.

[0003] In this concentrator / dehydrator, raw material consisting of water containing about 2-3% stock fiber is fed into the raw material storage tank through the raw material inlet. As the dehydrator drums rotate, the stock is dehydrated, and the stock fibers are carried upward while being caught on the edges of the holes and wire mesh. At the tangent point between the two dehydrator drums, the movable dehydrator drum is pressed against the fixed dehydrator drum by the action of the air spring, causing further dehydration. At the same time, the stock fibers caught on the movable rotating drum are drawn to the fixed rotating drum and formed into a single plate. This is then peeled off by a doctor and transported to the next process. Meanwhile, the water is drained through the drain outlet.

[0004] This type of concentrator / dehydrator achieves a high dehydration and concentration effect by filtering the wastewater through the dehydration drum by maintaining the water level inside and outside the drum, and by dehydrating and concentrating the wastewater by squeezing it at the contact points between the wire meshes.It is also cost-effective because it uses a natural vacuum system. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3433905 Summary of the Invention [Problem to be solved by the invention]

[0006] Recently, there has been a push to expand the uses of pulp, and it is anticipated that special pulps, such as alkaline pulp and non-wood pulps such as sugarcane, will be used as industrial materials. However, alkaline pulp, for example, needs to have its pH lowered to neutral to make it easier to process. Therefore, the pH is lowered by repeating the cycle of washing → dehydration → washing → dehydration, but it has been found that increasing the degree of dehydration in the dehydration process makes it easier to lower the pH, and efforts are being made to see if it is possible to dehydrate the material by squeezing the solids content down to 45-50% using alkali. Even when the above-mentioned type of concentrating dehydrator is used, the dehydration rate currently remains at 25 to 35%.

[0007] The present invention was made in response to the above-mentioned conventional problems, and aims to provide a new and useful concentrating and dehydrating machine that can achieve high dehydration by further improving the basic configuration of the concentrating and dehydrating machine described in Patent Document 1. [Means for solving the problem]

[0008] The present invention has been made to solve the above-mentioned problems and comprises a raw material storage tank into which moisture-containing raw material is supplied, a pair of dehydration drums stored in the raw material storage tank with their bodies arranged side by side in the horizontal direction, a rotating means for rotating the pair of dehydration drums in opposite directions so as to send upward raw material that has risen from below between the body parts, a raw material supply port provided in the raw material storage tank and communicating with the dehydration drums at the bottom, a drain port provided in the raw material storage tank and communicating with the inside of the dehydration drums, and a spacing between the body parts of one dehydration drum and the body part of the other dehydration drum such that the space between the body parts presses against the raw material that has risen between the body parts, and retracts and expands in an elastically recoverable manner depending on the thickness of the raw material to compress the raw material. the rotation shaft of one of the dehydration drums is rotatably inserted and guided by an insertion guide section provided on the tank surface of the raw material storage tank; a support body having a bearing for rotatably supporting the rotation shaft outside the raw material storage tank and extending perpendicular to the rotation shaft; an air spring provided on one side of the support body in the extension direction across the rotation shaft; and a swing fulcrum provided on the other side; the rotation shaft is able to shift position left and right within the insertion guide section as the air spring expands and contracts, allowing the body of one of the dehydration drums to retract elastically and recoverably relative to the body of the other dehydration drum.

[0009] Preferably, the insertion guide portion of the compression adjusting means is formed of a U-shaped notch provided on the tank surface of the raw material-accommodating tank and rotatably inserting and guiding the rotation shaft of one of the dehydration drums.

[0010] Preferably, when the support body is in a horizontal position, the distance between the barrel of one dewatering drum and the barrel of the other dewatering drum is minimized.

[0011] Preferably, the raw material storage tank has a U-shaped outline when viewed from the axial direction of the pair of dehydration drums, with the middle inner bottom surface being flat, and the opposing halves of the pair of dehydration drums being located on the flat surface.

[0012] Preferably, a plurality of raw material supply ports are provided below each of the pair of dehydration drums at intervals in the axial direction of the dehydration drums.

[0013] Preferably, the dehydration drum is constructed by stretching wire mesh on the outer and inner surfaces of a cylindrical drum made of punched metal, the punched metal having a thickness of 12 to 16 mm, an opening rate of 35 to 40%, an arrangement pattern of 60 to 45° zigzag, and a complete peripheral edge without any chips. [Effects of the Invention]

[0014] The concentrating dehydrator of the present invention is a further evolution of the concentrating dehydrator described in Patent Document 1, while retaining the basic configuration, with a focus on increasing the compression pressure, making it possible to achieve a higher dehydration rate than before. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a front view of a concentration dehydrator according to an embodiment of the present invention. [Figure 2] 2 is a top view and left and right side views of the concentration dehydrator of FIG. 1. [Figure 3] FIG. 2 is a front view of the concentration dehydrator in a state where the front tank surface portion is made transparent, in contrast to the front view of FIG. 1. [Figure 4] FIG. 4 is a front view of the closure plate of FIG. 3. [Figure 5] FIG. 2 is an explanatory diagram of the configuration of a drainage system that communicates with the inside of the dehydration drum in FIG. [Figure 6] 3A and 3B are explanatory diagrams of a pair of dehydration drums in a pressurized state and an open state. [Figure 7] FIG. 2 is an explanatory diagram of the arrangement pattern of punched holes in the punched metal that constitutes the body portion. DETAILED DESCRIPTION OF THE INVENTION

[0016] A concentration dehydrator 1 according to an embodiment of the present invention will be described with reference to the drawings. In the following description, directions are defined based on the front, back, left, right, top and bottom directions of the concentrating and dehydrating machine 1 shown in Figure 1. However, these directions are used for the convenience of explanation, and the present invention is not limited to these directions. As shown in the front view of Figure 1, a pair of leg frames 3, 3 are connected to the base frame 2 on the left side and a pair of leg frames 4, 4 are connected to the base frame 2 in an upright position with a gap between them in the left-right direction. A support frame 5 is connected to these leg frames 3, 3, 4, 4 in a direction that intersects with the perpendicular direction. The pair of leg frames 3, 3 is taller than the pair of leg frames 4, 4 and extends upward beyond the support frame 5. Another support frame 6 is connected to the upper end of the pair of leg frames 3, 3 in a horizontal position.

[0017] The support frame 5 supported by the pair of leg frames 4, 4 has an open top, and a swinging unit 7 is installed on the left side of the swinging unit 7. The swinging unit 7 is made up of a swing shaft 7a and a pair of mounting parts 7b, 7b, and one mounting part 7b is fixed to the support frame 5. An air spring 8 is installed on the right side of the swinging unit 7. The air spring 8 is made up of a rubber bellows 8a and a pair of face plates 8b, 8b, and one face plate 8b is fixed to the support frame 5.

[0018] Reference numeral 9 denotes a support frame, which is fixed in a state in which it is lifted and supported from below by the other mounting portion 7b of the swinging portion 7 and the other face plate 8b of the air spring 8. The support frames 5 and 9 are lined up vertically, with the support frame 5 extending further to the right. A locking piece 10 that protrudes to the right is attached to the right end of the support frame 9. A stopper bracket 11 is also attached to the extending portion of the support frame 5. A rod-shaped push-up limit stopper 12 is provided on this stopper bracket 11 and is threadedly engaged with a screw hole that passes through in the vertical direction. The stopper bracket 11 wraps around above the locking piece 10 from the right side, and the locking piece 10 is located below the lower end of the push-up limit stopper 12. Because the push-up limit stopper 12 is attached by threading into the screw hole, the position of the lower end of the push-up limit stopper 12 can be adjusted by screwing it in and out. In this embodiment, the support frame 9 is supported in a horizontally raised position in the maximum lifted state, and the upper surfaces of the support frame 9 and the left support frame 6 are substantially flush with each other. As shown in FIGS. 2 and 3, the frame structure is provided on both the front and rear sides.

[0019] Reference numeral 13 denotes a raw material storage tank. This raw material storage tank 13 is composed of a combination of metal plates, and the front and rear tank surfaces 14, 14 are symmetrical, forming a horizontally elongated U-shape, with the outline of the central bottom being linear. Therefore, the inner surface of the raw material storage tank 13 is composed of an inner bottom surface 13a, which is curved on the left and right ends and flat in the middle, and a rectangular frame-shaped inner side surface 13b, and is symmetrical about the center in the front-to-rear direction. The raw material storage tank 13 is surrounded from the front and rear by the frame structure, and is fixed at appropriate points to be raised and supported.

[0020] 3 and 4, a pair of closing plates 15, 15 are inserted into the raw material storage tank 13. The closing plates 15 have a horizontally long, symmetrical U-shape similar to the tank surface 14, and are installed in the raw material storage tank 13 with their plate surfaces parallel to the tank surface 14, dividing the raw material storage tank 13 in the front-to-rear direction. One closing plate 15 is located closer to the front tank surface 14, and the other closing plate 15 is located closer to the rear tank surface 14. However, the vertical dimension of the closing plates 15 is shorter than the vertical dimension of the tank surface 14. The tank surface 14 has rectangular notches 14a, 14a spaced apart in the left-right direction, and the closure plate 15 also has upwardly opening notches 16, 16 spaced apart in the left-right direction. The notches 16 are U-shaped, with the lower edge 16a forming a semicircular arc. The adjacent notches 16b, 16b, sandwiching the notch 16a, extend parallel to each other in the vertical direction. When viewed from the front-to-rear direction, the notches 16 are located within the notches 14a.

[0021] Closing plate 15 is provided with drainage ports 17, 17, each consisting of a horizontally elongated rectangular through-hole, spaced apart in the left-right direction. As shown in Figure 5, a gap is formed between closing plate 15 and tank surface 14, and opening 13c is formed on the underside of this gap, on the side facing raw material-storing tank 13, and opening 13c serves as the outlet for raw material-storing tank 13. Therefore, as shown by the arrow, water in dehydration drum 19 is discharged outside of thickening dehydrator 1. A raw material overflow port 18 is provided on the right side of the raw material storage tank 13. As shown by the dashed line in Figure 4, the water level in this raw material overflow port 18 is located below the notch 16 formed in the closing plate 15, so that the raw material does not flow from the center of the raw material storage tank 13 beyond the upper end of the closing plate 15 into the gap between the closing plate 15 and the tank surface 14. The raw material overflowing from the raw material overflow port 18 is circulated back into the raw material storage tank 13. Note that the raw material overflow port 18 is not shown in Figure 2.

[0022] A pair of dehydration drums 19A, 19B are housed in a space partitioned by a pair of closure plates 15, 15 within the raw material storage tank 13 configured as described above. The dehydration drums 19A and 19B have approximately the same size and shape, and when there is no need to distinguish between them, they will be referred to as dehydration drums 19. The body 20 of this dehydration drum 19 is cylindrical. The dehydration drum 19A is housed on the left side of the raw material storage tank 13, and the dehydration drum 19B is housed on the right side. The body parts 20, 20 are arranged side by side in the horizontal direction, and the rotation axes 21 extending in the axial direction of each are perpendicular to the tank surface 14. The raw material overflow port 18 is provided on the dehydration drum 19B side, which is the pressurized side.

[0023] Bearings 22, 22 are fixedly mounted on the support frames 6, 6, respectively. Notches 16, 16 and bearings 22, 22 are located in the axial direction of a rotating shaft 21 connected to the body 20 of the dehydration drum 19A, and the rotating shaft 21 passes through these notches 16, 16 and extends outward in the front-to-rear direction, with the extending portions rotatably supported by the bearings 22, 22, respectively. Bearings 22 are also installed and fixed on the support frames 9, and in a similar configuration, notches 16 and bearings 22 are positioned in the axial direction of a rotating shaft 21 connected to the body 20 of the dehydration drum 19B, and the rotating shaft 21 passes through these notches 16 and extends outward in the front-to-rear direction, with its extending portions rotatably supported by the bearings 22, respectively. The distance between opposing cutting edges 16b of notch 16 is set to be larger than the diameter of rotating shaft 21, so that rotating shaft 21 can be displaced left and right and up and down within the range surrounded by cutting edges 16a, 16b, 16b of notch 16. However, the width dimension (= distance between cutting edges 16b) of notch 16 through which rotating shaft 21 of fixed-side rotating drum 19A is inserted is 185 mm, and the width dimension of notch 16 through which rotating shaft 21 on the oscillating-side rotating drum 19B is inserted is 232 mm, so the latter is larger.

[0024] Dehydration drums 19A and 19B are accommodated in raw material storage tank 13 in a substantially symmetrical arrangement, with the lower left quarter-circular arc of dehydration drum 19A positioned on the curved left surface of the tank at a similar distance, and the lower right quarter-circular arc of dehydration drum 19B positioned on the curved right surface of the tank at a similar distance. Therefore, the opposing semicircular arc portions of body 20 of dehydration drum 19A and body 20 of dehydration drum 19B are positioned on the mid-plane of inner bottom surface 13a. Motors are connected to the rotary shafts 21, 21 of the dehydration drums 19A, 19B, respectively, so that the dehydration drums 19A and 19B are rotated around their axes in opposite directions by the motor drive.

[0025] Mounting members 26 are provided at both axial ends of the body 20 of the dehydration drum 19 for fixedly mounting the rotating shaft 21 to the body 20. The mounting members 26 include a boss portion through which the rotating shaft 21 is inserted and fixed, and a circular, flat flange portion 26a fixed to the body 20. These flange portions 26a are connected by a plurality of support bars 26b, 26b, ... extending uniformly radially from the outer periphery of the boss portion. The width of the flange surface of the flange portion 26a varies depending on the drum diameter. It is recommended that the flange surface width be set to a maximum of 125 mm for a drum diameter of 1700 mm, 110 mm for a drum diameter of 1500 mm, and 47 mm for a drum diameter of 600 mm. In this embodiment, the flange surface width is set to a maximum of 125 mm for a drum diameter of 1700 mm. Note that the boss portion is hidden by the bearing 22 in Figures 1 and 3. The slide seal material S is attached to this flange surface with a resin flat head screw. The slide seal material S can be made of a material with good surface lubricity, such as synthetic rubber such as highly elastic NBR rubber, or polymer resins such as high molecular weight polyethylene, ultra-high molecular weight polyethylene, polyacetal, silicone resin, fluororesin, and PA66 nylon. The sliding seal material S is pressed against a closure plate 15 having a bolt-nut structure BN using a bolt and nut as a pressing means, thereby sealing and closing the axial end side of the body part 20. The closure plate 15 is made of SUS (stainless steel) and has a polished surface, which provides excellent self-lubrication and sliding properties, ensuring sealing even when the body part 20 rotates.

[0026] As described above, drain port 17 is formed in closing plate 15. This drain port 17 is horizontally elongated and approximately rectangular, but the edge on the lower side is arcuate and follows the edge of flange portion 26a of mounting member 26. As shown in FIG. 5, a passage extending vertically is formed between closing plate 15 and tank surface portion 14, and this passage is connected to drain port 17 at its lower end. An opening 13c is formed in inner bottom surface 13a of raw material storage tank 13, which is the lower end of this passage. Therefore, all of the filtrate that has flowed into body portion 20 and is located higher than flange portion 26a is drained to the outside. Because the width of the flange surface of flange portion 26a is set as small as possible, the filtrate does not accumulate inside body portion 20 and is immediately drained to the outside.

[0027] The dehydration drum 19A is fixed in position within the raw material-storing vessel 13 because the axial direction of the rotation shaft 21 of the dehydration drum 19A does not move within the raw material-storing vessel 13. In other words, the dehydration drum 19A is the fixed side. In contrast, dehydration drum 19B is the oscillating side, and is supported by oscillating section 7 on the left side of support frame 9 and air spring 8 on the right side, and in the middle of support frame 9, a perpendicular rotating shaft 21 is loosely fitted into notch 16 and guided. When the right side of the support frame 9 is pushed up by the pressure of compressed air from the air spring 8, the lower end face of the push-up limit stopper 12 comes into contact with the locking piece 10, restricting further pushing up, and at that time the upper surface of the support frame 9 becomes flush with the upper surface of the support frame 6 and aligned in the left-right direction. In this state, the body 20 of dehydrating drum 19A and the body 20 of dehydrating drum 19B face each other in the left-right direction. The tangents extending in the up-down direction on the opposing sides of the body 20 of dehydrating drum 19A and the body 20 of dehydrating drum 19B substantially coincide. The distance (clearance) between the body 20 of dehydrating drum 19A and the body 20 of dehydrating drum 19B is set to achieve the maximum compression pressure applicable to the anticipated raw material, and is set accordingly in this embodiment. In this embodiment, the position of the lower end of the push-up limit stopper 12 is set as described above, but the position of the lower end can be moved vertically by threading the screw forward and backward, and the rotating shaft 21 can also be displaced within the range of the notch 16, so that the tangent portion on the body 20 side of the dehydration drum 19B can be moved left and right to fine-tune the distance (clearance) between the body 20 of the dehydration drum 19A and the body 20 of the dehydration drum 19B.

[0028] Due to the effects of air spring 8 and push-up limit stopper 12, body 20 of dehydration drum 19B is always biased in a direction to maintain a set constant clearance relative to body 20 of dehydration drum 19A. When body 20 of dehydration drum 19B receives a force in a direction away from body 20 of dehydration drum 19A against the biasing force, the force is transmitted to air spring 8 via rotating shaft 21, bearing 22, and support frame 9, causing air spring 8 to contract and lower, and accordingly, swinging part 7 swings, causing body 20 of dehydration drum 19B to move in a direction away from body 20 of dehydration drum 19A, widening the gap (clearance). Therefore, the tangent portion on the side of dehydration drum 19B shifts to the right.

[0029] However, since the range in which the rotary shaft 21 can move is limited to the range of the notch 16, the above-mentioned positional deviation is contained within that range. Then, when the force resisting the biasing force disappears or weakens, the air spring 8 expands and rises, returning to or approaching its original state, i.e., the gap (clearance) narrows. Figure 6 shows the pressurized state (filled with air and sealed) and the open state (deflated state) of the air spring 8. It is always pressurized during the dehydration process, but in the open state, the air spring 8 is in its most compressed state with the air deflated, resulting in the greatest displacement. In the pressurized state, the air spring 8 does not displace to this extent, but please use this as a reference to show the deformed state of displacement. In conventional concentrating dehydrators of this type, an air spring lifts half of the raw material storage tank to move one of the dehydration drums. However, a feature of the present invention is that air spring 8 directly lifts dehydration drum 19B, and the load on air spring 8 is lighter, making it easier to maintain the maximum lifted state on the dehydration drum 19B side. On the other hand, when a force is applied in the contracting direction, the air spring quickly contracts, but when the force is removed, the air spring quickly returns to the maximum lifted state.

[0030] The body 20 of the dehydration drum 19 is a cylindrical body formed from punched metal, with mesh wire screens stretched on both the inner and outer circumferential surfaces. The wire screen (upper screen) stretched on the outer circumferential surface has a finer mesh than the wire screen (lower screen) stretched on the inner circumferential surface. Furthermore, the mesh of the upper screen on the body 20 on the dehydration drum 19A side is finer than that of the body 20 on the dehydration drum 19B side. In this embodiment, the lower screen is 8 mesh, and the upper screen on the dehydration drum 19B side is 14 mesh, and the upper screen on the dehydration drum 19A side is 20 mesh. However, this setting is not fixed and can be changed as appropriate depending on the type of raw material, design changes to other parts of the concentration dehydrator 1, etc. For example, the wire screen (upper screen) on the dehydration drum 19B side may be 20 mesh and the upper screen on the dehydration drum 19A side may be 30 mesh, or even finer.

[0031] The thickness of the punched metal is set to 12 to 16 mm. Existing concentrating dehydrators of this type are 10 mm thick, but this concentrating dehydrator 1 is thicker and stronger. When the compression pressure, i.e., the applied pressure, is increased, the body portions 20, 20 are also subjected to a strong applied pressure, which may make them more susceptible to deformation, but because the body portions 20, 20 are thicker and stronger as described above, they can withstand the increased pressure and are prevented from being deformed or damaged. Therefore, the dehydration drum 19 is directly lifted and supported by the air spring 8, which allows for stronger pressure, and the increased strength of the body 20 of the dehydration drum 19 makes it less likely to deform, making it possible to increase the compression pressure more than before.

[0032] Furthermore, the opening ratio of the punched metal is set to 35 to 40%, the arrangement pattern is staggered at 60 to 45 degrees, and the edges are configured so that no part of the hole edge is exposed, i.e., the edges are configured to be complete and free of chips. As shown in Figure 7, even when the hole diameter (D) and hole spacing (P) are the same, the open area ratio (%) is significantly different when comparing a 60° staggered pattern with a square staggered pattern (= 45° staggered pattern). The perforated metal that makes up the body 20 is set in a 60° staggered pattern (hole diameter (D): 18 mm, hole spacing (P): 28 mm, open area ratio: 37.4%), and this arrangement pattern continues all the way to the axial end. By configuring the body 20 in such a fixed arrangement pattern, the entire circumferential surface, particularly the entire axial length, can be used for suction without waste.

[0033] A plurality of raw material supply ports 23 are provided on the flat bottom surface of the raw material storage tank 13. The left-side raw material supply ports 23, 23, 23 are located below the dehydration drum 19A and are aligned at a fixed distance from each other in the front-to-rear direction. However, the raw material supply ports 23, 23 on both front-to-rear directions are close to the tank surfaces 14, 14, respectively. The right-side raw material supply ports 23, 23, 23 are similarly positioned relative to the dehydration drum 19B, for a total of six raw material supply ports 23, 23, ... arranged symmetrically. The tips of the raw material supply pipes extend tangentially from the outside in the left-to-right direction directly below the dehydration drum 19, and the raw material supply port 23 at its tip opens directly below the dehydration drum 19 and communicates with the raw material storage tank 13. The raw material supply ports 23, 23, ... are connected to a header pipe 24 directly attached to a pump via hoses 25, 25, .... The header pipe 24 is connected to a raw material supply passage and communicates with the inside of the raw material storage tank 13 via a raw material supply port 23 .

[0034] As shown in Fig. 3, a doctor blade 27 and a scraping conveyor 28 are provided on the side of dehydration drum 19A, which is the fixed side. The scraping conveyor 28 is disposed inside a housing 28a, and the front portion of the housing 28a is made transparent in Fig. 3.

[0035] The concentrating and dehydrating machine 1 is configured as described above, and its operation from the time when the raw material is supplied until the time when the raw material is discharged will be described. Dewatering drum 19A rotates counterclockwise around its axis, and dewatering drum 19B rotates clockwise around its axis. Air spring 8 is sealed and filled with air, and extends to a height regulated by push-up limit stopper 12. As described above, the effect of air spring 8 causes body portion 20 on dewatering drum 19B to always maintain a constant distance (clearance) from body portion 20 on dewatering drum 19A. This constant distance (clearance) is set so that the maximum compression pressure is achieved within an allowable range for the raw material mat being compressed, taking into account the strength of dewatering drum 19.

[0036] In this state, when a water-containing raw material, for example, a slurry of alkaline pulp, is blown out and supplied from the raw material supply ports 23, 23, ..., it is sucked by natural vacuum toward the body 20 on the dewatering drum 19A side and the body 20 on the dewatering drum 19B side, respectively, and moves toward the boundary between the body portions 20. In the process, the moisture in the raw material flows into the dewatering drum 19 through the punched holes in the body portion 20 and is discharged through the drainage port 17. Therefore, the water is naturally filtered out. The raw material mat that does not enter the dewatering drum 19 adheres to and accumulates on the wire mesh. This raw material mat is sent upward through the gaps on the opposing sides of the body portion 20 on the dewatering drum 19A side and the body portion 20 on the dewatering drum 19B side.

[0037] The raw material mat fed between the barrels 20, 20 is subjected to a force from the barrels 20, 20 pushing it down to a certain gap (clearance), but the raw material mat also exerts a force pushing it back against the barrels 20, 20 in accordance with its thickness, and the pressure tends to balance. Therefore, as the raw material mat becomes thicker, it quickly retreats, widening the gap (clearance) between the barrels 20, 20, and as the raw material mat loses its thickness, the gap (clearance) returns to the initial setting or close to it. In other words, any fluctuations in thickness are quickly absorbed. Therefore, even if the thickness of the raw material mat varies, it is always possible to compress the raw material mat at a high compression pressure according to the thickness, and the raw material mat is dehydrated to a high concentration in one go. The dewatered raw mat then transfers to the dewatering drum 19A, adhering to it as a single plate, and is peeled off by the doctor 27 at a position where it has rotated about 120 degrees. It is then crushed into small pieces by the scraping conveyor 28 and transported to the next process. The water that is extracted during the squeezing is drained from the drain outlet 17.

[0038] Furthermore, the entire peripheral surface of the body 20 can be utilized for suction without waste, and the raw material supply ports 23, 23, 23 are oriented toward the middle and both ends of the body 20, respectively, in particular in the axial direction, so that the raw material blown out and supplied from the raw material supply port 23 comes into uniform contact with the entire length of the body 20, particularly in the axial direction, and is sucked in. Therefore, the amount of material squeezed is uniform throughout the axial length, and the material is squeezed and dewatered to the same extent everywhere. Conventionally, there were no punch holes on either end of the body in the axial direction, and there was only one raw material supply port in the center, which resulted in insufficient dehydration on either end of the body in the axial direction, but the present invention eliminates these inconveniences.

[0039] As described above, improvements from multiple perspectives are effectively combined, and the concentrating dehydrator 1 ensures higher dewatering performance than the existing concentrating dehydrator of Patent Document 1. In the case of alkaline pulp, it has been confirmed that it can be squeezed and dewatered to a solid content of 45 to 50% including alkali.

[0040] Furthermore, inner bottom surface 13a of raw material storage tank 13 is flat except for the left and right ends, and the boundary between dehydration drums 19A and 19B is also flat, so there is a wide gap between inner bottom surface 13a and the boundary between dehydration drums 19A and 19B, and as shown in Figure 6, when air spring 8 is released, the width dimension of notch 16 is set larger on the dehydration drum 19B side as described above, so that body 20 of dehydration drum 19B moves significantly to the right, sufficiently widening the gap with body 20 of dehydration drum 19A. This makes it easy to clean the inside of raw material storage tank 3.

[0041] Although the embodiments of the present invention have been described in detail above, the specific configuration is not limited to these embodiments, and the invention also includes design changes within the scope of the present invention without departing from the gist of the present invention. For example, in this embodiment, the slide seal material S is attached to the annular flange portion on the dehydration drum 19 side, but it can also be attached to the closure plate 15 side. [Explanation of symbols]

[0042] 1... Concentration dehydrator 2... Base frame 3...Leg frame 4...Leg frame 5...Support frame 6...Support frame 7...Swinging portion 7a...Swinging shaft 7b...Mounting part 8...Air spring 8a…Rubber bellow 8b…Face plate 9...Support frame 10...Latching piece 11...Stopper bracket 12...Lift limit stopper 13...raw material storage tank 13a...inner bottom surface 13b…Inner surface 13c…Opening 14...tank surface part 14a...missing part 15...Closure plate 16...Notch 16a...Cutting edge 16b...Cutting edge 17...Drain outlet 18...Raw material overflow port 19A, 19B... Dehydration drum 20... Body 21...Rotating shaft 22...Bearing 23... Raw material supply port 24... Header pipe 25... Hose 26... Mounting member 26a...flange portion 26b...support beam 27...Doctor 28...Scraper conveyor 28a…Housing S...Slide seal material BN...Bolt and nut structure

Claims

1. a raw material storage tank to which the water-containing raw material is supplied; a pair of dehydration drums housed in the raw material storage tank with their body portions arranged side by side in a horizontal direction; a rotating means for rotating the pair of dehydration drums in opposite directions so as to send upward the material that has risen from below between the drums; a raw material supply port provided in the raw material storage tank and communicating with the dehydration drum at a lower side; a drain outlet provided in the raw material storage tank and communicating with the inside of the dehydration drum; a compression adjusting means for adjusting the gap between the barrels of one dehydration drum and the barrel of the other dehydration drum to allow the material to be compressed while being pressed against the material that has risen between the barrels and retracting and expanding in an elastically recoverable manner depending on the thickness of the material; The compression adjustment means is composed of an insertion guide portion provided on the tank surface of the raw material storage tank to rotatably insert and guide the rotating shaft of one of the dehydration drums, a support body having a bearing that rotatably supports the rotating shaft outside the raw material storage tank and extending perpendicular to the rotating shaft, an air spring provided on one side of the support body in the extension direction across the rotating shaft, and a swing fulcrum provided on the other side, and the rotation shaft can be displaced left and right within the insertion guide portion as the air spring expands and contracts, thereby allowing the body of one of the dehydration drums to elastically recover and retreat relative to the body of the other dehydration drum.

2. In the concentrating and dehydrating machine according to claim 1, A concentrating dehydrator characterized in that the insertion guide portion of the compression adjustment means is composed of a U-shaped notch provided on the tank surface of the raw material storage tank and rotatably inserting and guiding the rotating shaft of one of the dehydration drums.

3. In the concentrating and dehydrating machine according to claim 2, A concentrating dehydrator characterized in that when the support is in a horizontal position, the distance between the body of one dehydration drum and the body of the other dehydration drum is minimized.

4. In the concentrating and dehydrating machine according to claim 3, A concentrating dehydrator characterized in that the raw material storage tank has a U-shaped outline when viewed from the axial direction of a pair of dehydration drums, the middle inner bottom surface is flat, and opposing halves of the pair of dehydration drums are located on the flat surface.

5. In the concentrating and dehydrating machine according to claim 4, A concentrating and dehydrating machine characterized in that a plurality of raw material supply ports are provided below each of a pair of dehydrating drums at intervals in the axial direction of the dehydrating drums.

6. The concentrating and dehydrating machine according to any one of claims 1 to 5, The dehydration drum is made of a cylindrical drum made of punched metal with wire mesh stretched on the outer and inner surfaces. The perforated metal has a thickness of 12 to 16 mm, an opening rate of 35 to 40%, an arrangement pattern of 60 to 45° zigzag, and a complete peripheral edge without any chipping.

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