JP2009142791A - Screw press with concentration function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw press with a concentration function which concentrates a lot of sludge of low concentration having a larger water load than a solid material load to produce a dewatered cake of low water content. <P>SOLUTION: The screw press with the concentration function forms a concentration room 13a with a pair of disk like concentration screens 11 and a filtration-room outer ring 12, is arranged with an impeller wheel 7 having an impeller 21 bent in the rotary direction of the wheel, is opened a supplying opening 12, 12a, 12b of a raw liquid sludge in the filtration-room outer ring 12 and a sludge supplying hole 23 of a concentrated sludge in an impeller boss 20, projects a screw shaft 4, arranged in a dewatering screen 2 of a screw press 6, inside the impeller boss 20, rotates the impeller wheel 7 and a screw blade 3 in the same direction, scrapes a solid content, captured by the concentration screen 11, with a side edge of the impeller 21 to discharge a lot of filtrate, and makes the impeller 21 of the concentration room 13 communicate with the screw blade 3 of the filtration room 5 to generate a pushing pressure and a leading action so that the concentrated sludge of high concentration can be supplied to the screw press 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  This invention combines a concentrator and a screw press to concentrate a large volume of sludge with a lower water concentration than a solid load while preventing clogging and reducing the variation in moisture content of the dehydrated cake. The present invention relates to an improvement of a screw press with a concentration mechanism that enables high dehydration.

  Conventionally, organic sludge having a low concentration is concentrated by a centrifugal concentrator or a flotation concentrator and then filtered and dehydrated. For example, in a screw press, sludge having a concentration of 1% is concentrated to 4 to 5%, and this concentrated sludge is filtered and dehydrated. All of these concentrators have a large installation area, and the driving power cost and the cost of the polymer flocculant are high, and the maintenance is troublesome. When organic sludge with low concentration is directly concentrated and dehydrated with a screw press, the sludge concentration is low on the sludge injection side of the screw press, so the concentration screen in the concentration zone has a larger water load than the solid load, and a large amount from the concentration screen. Need to drain the water. Conventionally, in a screw press, flocs are generated by adding a polymer flocculant to organic sludge such as sewage, human waste, or food production processing wastewater. Clogging is likely to occur, and residues adhere to the concentration screen in the concentration zone, making it difficult to regenerate the screen surface with a low-speed screw blade.

In order to process a large amount of sludge with a large concentration and a low water concentration, which is larger than the solid load, a solid-liquid separation device combining a conventional screw press with a concentrating device is an outlet of a vertical cylindrical screen provided with screw blades. Is connected to the supply port of the screw press, and there is a sludge concentration and dehydration device that concentrates the raw liquid sludge introduced from the lower part by gravity while transferring it upward with screw blades and discharges the separated liquid from the peripheral part of the cylindrical screen. This is known as described in Patent Document 1. In addition, a concentrator that hangs the screw blades on the filter cylinder and connects the lower end of the filter cylinder to the start end of the dewatering cylinder of the screw press to separate the filtrate by gravity in the vertical position and the conveying pressure of the screw blades. The continuous pressure dehydrator used has also been proposed by the applicant of the present invention as described in Patent Document 2, for example.
Japanese Patent Publication No. 6-15117 (Claim 1 and column of action, Fig. 1) Japanese Patent No. 3800408 (paragraph numbers 0014 to 0016, FIGS. 1 and 2)

  As a conventional sludge concentrating device, a cylindrical screen and a filter tube combined with a screw press supply port have an advantage that solid-liquid separation is promoted by the sludge gravity and the transfer force and pushing pressure of rotating screw blades. Even with organic sludge with a large water load that is prone to clogging, the screen surface can be regenerated by adjusting the rotational speed of the screw blades, and low-concentration sludge can be concentrated without clogging. Concentrated sludge can be continuously supplied to the screw press, but a cylindrical screen has a limited concentration treatment capacity because a large filtration area for separating the filtrate cannot be obtained. In order to increase the processing capacity, if the number of sliding contact of the spiral screw blades on the screen surface inside the cylinder is increased, the aggregated flocs may be destroyed.

  The gist of the screw press with a concentration mechanism according to the present invention is that a screw shaft in which a screw blade is wound around a dewatering screen is provided, and sludge supplied to the filtration chamber between the dewatering screen and the screw shaft is transferred by the screw blade. In a screw press that separates the filtrate from the dewatering screen and removes the dehydrated cake from the end of the filtration chamber, a pair of disk-shaped concentration screens are arranged around the start end of the dewatering screen, and the outer periphery of the concentration screen An annular outer ring is fitted to form an annular concentrating chamber, and an impeller is arranged in the concentrating chamber to form a concentrator, and a raw sludge supply port and an impeller blade are provided in the outer annular ring. Concentrated sludge feed hole is opened in the boss, and the screw shaft built in the dewatering screen is projected inside the blade boss. Since the separation of the filtrate from a wide left and right disk-like concentrated screen of filtration area of Chijimishitsu, it is possible to sludge concentrated by the large-volume treatment. The solids captured by the concentrating screen are scraped at the left and right side edges of the impellers of multiple impellers, so that the filtration surface, which is clogged, is continuously regenerated, resulting in good solid-liquid separation. A large amount of filtrate can be discharged without clogging. Moreover, since highly concentrated sludge is supplied to the screw press, a highly dehydrated cake with little variation in moisture content can be obtained.

  The impeller of the impeller disposed in the concentrator is bent in the rotational direction of the impeller, and the raw sludge flows along the curved surface of the impeller impeller and stirs the sludge to break up the aggregated flocs. Indentation pressure can be generated. The impeller of the concentrator is rotated in the same direction as the rotation of the screw blade disposed in the screw press. The concentrated sludge from which the filtrate has been separated has an increased contact pressure on the impeller surface and has a slip resistance. The impeller of the concentrating chamber of the concentrator and the screw blade of the filtration chamber of the screw press work together to generate indentation pressure and pull-in action, without causing a large load on the blade boss mud hole, Concentrated sludge can be supplied from the concentration chamber to the filtration chamber.

  Multiple sludge supply ports are opened in the outer ring of the concentrator filter, and the raw sludge is pressed into the front and back surfaces of the impeller bent on the impeller. The sludge is uniformly supplied between the plurality of impellers provided, so that the condensed floc can be made uniform without breaking the flocs. In addition, a notch groove is provided at the tip of the impeller fixed to the impeller, and the raw liquid sludge flows evenly between the impellers fixed to the impeller by flowing the raw sludge before and after the impeller. Dispersed and separated concentrated sludge that has separated the filtrate from the concentration screen can be supplied to the screw press. Further, a plurality of communication holes may be provided on the impeller blade surface fixed to the impeller, and sludge can be evenly distributed between the plurality of impellers while separating the filtrate from the concentration screen.

  The concentrating screen stretched in the concentrating chamber is composed of a plurality of concentric annular divided metal filter media, and the fine holes of the divided metal filter media are gradually reduced from the circumferential part toward the central part. The increase in the amount of filtrate to be discharged toward the section and the amount of open SS are suppressed, the throughput of sludge increases without suspending the filtrate, and the concentration rate also improves. In the vicinity of the outer ring of the filter where the sludge concentration is low, the micropores are enlarged, and the micropores in the inner periphery where the frictional resistance is generated by concentrating with the rotation of the impeller is reduced. A large amount of sludge with a large concentration can be treated.

  The present invention is configured as described above, and when sludge is pressed into the concentrating chamber from the supply port of the outer ring of the filter chamber while rotating the impeller disposed in the concentrator at a slow speed, the impeller is wrapped in the front and rear impellers as the impeller rotates. It is held and transferred along the filtration surface of the concentration screen. The sludge having a larger water load than the solid load is separated from the right and left concentration screens mainly by the press-fitting pressure in the vicinity of the outer ring of the filter chamber immediately after the press-fitting. The filtrate is separated from the concentration screen by the pressure of sludge from the supply port of the filter outer ring and the pressure of the impeller bent in the rotation direction. A solid layer is gradually formed on the filtration surface of the concentration screen, and frictional resistance is generated between the solid layer on the filtration surface and the sludge, thereby promoting dehydration. At the same time, the side edge of the rotating impeller continuously contacts the left and right concentration screens to regenerate the filtration surface, so that the concentration screen can be continuously filtered without clogging. As the impeller rotates, pressure is applied from different directions, and the concentrated sludge generates not only a pressing force from one direction but also a shearing action. Concentrated sludge is transferred to the filtration chamber of the screw press without causing a large load on the mud supply hole of the blade boss in conjunction with the pulling action of the screw blade rotating in the same direction as the pushing pressure of the impeller bent in the rotation direction Can be pressed and dehydrated. Large-capacity sludge treatment is possible, and a dehydrated cake with a low moisture content that does not vary is obtained.

  An embodiment of the present invention will be described in detail with reference to the drawings. First, FIG. 1 is a longitudinal sectional view of a screw press with a concentration mechanism, and the screw press 1 with a concentration mechanism has a screw blade 3 wound around a dehydrating screen 2. A screw press 6 in which a screw shaft 4 is provided and a filtration chamber 5 is formed between the dewatering screen 2 and the screw shaft 4, and a circular wheel in which an impeller 7 is provided continuously to the periphery of the start end of the dewatering screen 2. An annular concentrator 8 is used, and the screw shaft 4 of the screw press 6 projects from the shaft core of the concentrator 8. The screw press 6 is provided with a tapered screw shaft 4 in a cylindrical dewatering screen 2, and the volume of the filtration chamber 5 is gradually reduced from the start end side toward the discharge side. In the screw press 1 with a concentrating mechanism, the central portion of the concentrator 8 provided with a pre-stage concentrator 8 and a screw shaft 4 is provided as a concentrating zone A, and the inside of the dewatering screen 2 of the screw press 6 is used as a dehydrating filtration zone B. . A screen driver 9 is coupled to the dewatering screen 2 of the screw press 6, and a screw driver 10 is coupled to the screw shaft 4, and the dewatering screen 2 is brought into sliding contact with a concentrator 8 supported on a machine frame (not shown). Thus, the dewatering screen 2 of the screw press 6 and the screw shaft 4 can be rotated at a differential speed. If necessary, if the dewatering screen 2 and the screw shaft 4 of the screw press 6 are rotated in reverse, the concentrated sludge supplied from the concentrator 8 can be subjected to a shearing action to enhance the squeezing effect. When the dewatering screen 2 is clogged, if the dewatering screen 2 and the screw shaft 4 are rotated in the same direction, the overload of the screw driving machine 10 of the screw shaft 4 can be reduced, and the cake can be discharged. If the washing water is jetted while the dewatering screen 2 is clogged, the clogging of the dewatering screen 2 can be solved uniformly.

  FIG. 2 is a longitudinal sectional view of a main part of the concentrator disposed in the screw press with a concentrating mechanism. The concentrator 8 disposed at the starting end of the dehydrating screen 2 includes a pair of disk-shaped concentrating screens 11 and 11. An annular concentrating chamber 13 is formed by the filter chamber outer ring 12 fitted to the outer periphery of the concentration screens 11, 11, and a sludge supply port 14 is opened in the filter chamber outer ring 12. An inner ring support frame 15 is fitted on the inner periphery of the concentration screens 11, 11, and a mud supply chamber 13 a is formed inside the inner ring support frame 15. FIG. 3 is a front view of the concentration screen, and the concentration screen 11 is composed of a plurality of concentric annular divided metal filter media 11a, 11b, and 11c, and the fine holes of the divided metal filter media 11a, 11b, and 11c are arranged around the circumference. It is reduced gradually from the center toward the center. The micropores are enlarged in the vicinity of the low-concentration circumferential filter outer ring 12, and the micropores are reduced in the vicinity of the inner ring support frame 15 in the inner circumference where the frictional resistance is generated by the rotation of the impeller 7. As a result, the increase in the amount of filtrate to be discharged from the outer peripheral part toward the center part and the amount of SS that pass through are suppressed, the amount of sludge treated increases, and the concentration rate of sludge improves without suspending the filtrate. To do. FIG. 4 is a front view of an essential part of the concentrator, and the concentrating screen 11 of the concentrator 8 includes a filter outer ring 12 and an inner ring support frame 15 fitted to the outer peripheral portion and inner peripheral portion of the concentrating screen 11, respectively. The outer peripheral part of the concentration screen 11 is reinforced by connecting a plurality of annular frames 16. As shown in FIGS. 1 and 2, an annular frame 18 is fitted on the outer periphery of the starting end of the dewatering screen 2, the side edges of the annular frame 18 and the inner ring support frame 15 are abutted and sealed on the facing surface side. The materials 19 and 19 are fitted.

  FIG. 5 is a partially longitudinal front view of the impeller disposed in the concentrating chamber. The impeller 7 disposed in the concentrating chamber 13 has a plurality of impellers 21 fixed to a cylindrical blade boss 20. A notch groove 22 is formed at the tip of the impeller 21 and a plurality of mud supply holes 23 for concentrated sludge are opened in the blade boss 20. The flanges 20a are formed at both ends of the blade boss 20 of the impeller 7, and the start end side inside the blade boss 20 is closed by the side plate 20b. As shown in FIG. 1, the flanges 20 a and 20 a of the blade boss 20 of the impeller 7 are held by the annular frame 18 of the dewatering screen 2 and the inner ring support frame 15 of the concentrator 8 supported on the machine frame (not shown). The impeller 7 is rotatable by being held and sealed with sealing materials 19 and 19 and linked to the impeller drive unit 24. The impeller 21 of the impeller 7 extending to the concentrating chamber 13 has a tip end close to the filter chamber outer ring 12 and the side edges of the impeller 21 are in sliding contact with the left and right concentrating screens 11, 11. The tip of the screw shaft 4 around which the screw blade 3 projecting from the dewatering screen 2 is wound is opposed to the mud supply hole 23 of the blade boss 20 of the impeller 7 disposed in the concentrator 8. The inside of the blade boss 20 is used as a press-fitting chamber 25 for concentrated sludge.

  FIG. 6 is a longitudinal side view of the impeller. A plurality of impellers 21 fixed to the impeller boss 20 of the impeller 7 are arranged in the concentrating chamber 13 by bending the tip in the rotational direction. In the embodiment of the present invention, the impeller 21 is advanced in the rotational direction by bending four straight pieces to approximate a bent line. As shown in FIG. 2, if the raw sludge supply port 14 opened to the outer ring 12 of the concentrating chamber 13 opens symmetrically to the annular outer ring 12, the raw sludge is impeller 21 of the impeller 7, It is possible to press-fit more evenly between 21. As conceptually shown in FIG. 6, in the embodiment of the present invention, the supply port 14 a is supplied to the filter chamber outer ring 12 obliquely above in the rotational direction of the impeller 21, and the filter chamber outer ring 12 obliquely below in the rotational direction is supplied. The opening 14b is provided at a position where the center position of the annular filter outer ring 12 is symmetric. The sludge that is press-fitted into the concentrating chamber 13 of the concentrator 8 includes the front surface of the bent blade surface of the impeller 21 that is fixed to the impeller 7 that rotates from the upper and lower symmetrical positions of the concentrating chamber 13 and the blade Since it is press-fitted between the rear surfaces and the raw sludge flows along the blade surfaces of the front and rear impellers 21, the soft coagulated flocs are not broken under the influence of the rotating impellers 21, and the dehydrating property is reduced. It will not be damaged.

  As shown in FIG. 5, a notch groove 22 is provided at the tip of the impeller 21 of the impeller 7, and sludge press-fitted between the impellers 21, 21 is caused to flow back and forth from the notch groove 22 to impeller 7. Sludge can be evenly supplied between the plurality of impellers 21. As shown in FIG. 7, in another embodiment, in order to disperse fluid sludge evenly in the concentrating chamber 13, the impeller 21a of the impeller 7a is connected to the front and back surfaces of the bent blade surface. A plurality of communication holes 26 are provided, and sludge can be evenly distributed between the plurality of impellers 21 a while separating the filtrate from the concentration screen 11. In the vicinity of the filter outer ring 12 close to the supply ports 14a and 14b, since the sludge concentration is low and the fluidity is high, the press-in pressure is increased and the press-in pressure and the pushing action of the impeller 21 bent are combined. Transport the raw sludge. In the concentrating chamber 13, even if the sludge has a larger water load than the solid load, a large amount of filtrate can be discharged from the left and right concentrating screens 11, 11, and the side edge of the impeller 21 is slidably contacted with the concentrating screen 11 that is clogged Thus, the filtrate is separated while preventing clogging, and the throughput of sludge concentration is increased. In the vicinity of the blade boss 20 of the impeller 7, the contact pressure between the concentrated sludge and the impeller 21 front surface of the bent impeller 21 is increased to reduce the slip resistance, and the mud supply hole 23 provided in the blade boss 20 is large. Without causing a load, high-concentration concentrated sludge is transferred from the feed mud hole 23 to the press-fitting chamber 25 to increase the amount of sludge treatment in the dewatering / filtration zone B, and a dewatered cake with a uniform and low water content can be obtained. .

  The rotation of the impeller 7 disposed in the concentration chamber 13 of the concentrator 8 and the screw shaft 4 disposed in the filtration chamber 5 of the screw press 6 are rotated in the same direction. The concentrated sludge from which the liquid has been separated increases the contact pressure on the blade surface of the impeller 21 to reduce slip resistance, and the impeller 7 of the concentrator chamber 13 of the concentrator 8 and the screw blade 3 of the filter chamber 5 of the screw press 6 Since the pushing pressure and the pulling action are generated in conjunction with each other, the concentrated sludge can be supplied from the concentration chamber 13 to the filtration chamber 5 without causing a large load on the mud supply holes 23 of the blade boss 20. . The concentrated sludge supplied to the press-fitting chamber 25 inside the blade boss 20 is transferred to the filtration chamber 5 of the screw press 6 by the screw blade 3 and filtered and dehydrated. If the dewatering screen 2 is rotated in the direction opposite to the screw shaft 4, the relative rotational speed of the screw shaft 4 is increased, and the pushing pressure in the dewatering / filtration zone B is increased while the concentration density is increased. Clogging can be prevented in advance. When cake is excessively accumulated in the filtration chamber 5 of the dehydration / filtration zone B and the internal pressure becomes abnormally high, if the dehydration screen 2 is rotated in the same direction as the screw shaft 4, the cake is overloaded. Can be reduced, and foreign matter in the vicinity of the outlet of the filtration chamber 5 can be eliminated. If a cleaning pipe (not shown) is disposed along the peripheral surface of the dewatering screen 2 and the cleaning water is sprayed onto the rotating dewatering screen 2, the contact surface between the cake and the screen is lubricated by the cleaning water. Clogging of the screen surface of the dewatering screen 2 is prevented, solid-liquid separation is promoted, large-capacity sludge treatment is possible, and a highly dehydrated cake with little variation in moisture content can be obtained.

  The screw press with a concentrating mechanism according to the present invention is formed by forming an annular concentrating chamber in the periphery of the start end of the dehydrating screen of the screw press, and disposing the impeller in which the impeller is bent in the rotational direction. Concentrate by opening a feed port for the raw sludge in the outer ring of the filter chamber and a feed hole for the concentrated sludge in the blade boss, and projecting the screw shaft built in the dewatering screen inside the blade boss of the concentrator. Because the rotation of the impeller of the machine rotates in the same direction as the screw blade wound around the screw shaft, the bent impeller does not stir the sludge and break up the flocs flocs, and it has a disk shape with a wide filtration area. The filtrate can be separated from the left and right concentration screens. Since the solid content captured by the concentration screen is scraped continuously at the side edge of the impeller, even a sludge having a low concentration and a large water load can discharge a large amount of filtrate without clogging. Concentrated sludge can be supplied to the screw press from the concentrating chamber by generating pressure and pulling action in conjunction with the impeller of the concentrating chamber and the screw blades of the filtering chamber, and the moisture content varies. A highly dehydrated cake can be obtained, and a large volume of untreated sludge can be processed. Therefore, it is a screw press suitable for a treatment plant that requires a large volume of treatment such as sewage mixed raw sludge, sewage digested sludge, activated surplus sludge and the like.

It is a longitudinal cross-sectional view of the screw press with a concentration mechanism which concerns on this invention. Similarly, it is a principal part longitudinal cross-sectional view of the concentrator arrange | positioned at the screw press with a concentration mechanism. Similarly, it is a front view of a concentration screen. Similarly, it is a principal part front view of a concentrator. Similarly, it is a partial longitudinal sectional front view of an impeller disposed in the concentration chamber. Similarly, it is a vertical side view of an impeller. Similarly, it is a vertical side view of another embodiment of an impeller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Dehydration screen 3 Screw blade 4 Screw shaft 5 Filtration chamber 6 Screw press 7 Impeller 8 Concentrator 11 Concentration screen 11a, 11b, 11c Division | segmentation metal filter material 12 Filter outdoor ring 13 Concentration chamber 14, 14a, 14b Supply port 20 Blade boss 21 Impeller 22 Notch groove 23 Mud hole 26 Communication hole

Claims (7)

  The screw shaft (4) around which the screw blade (3) is wound around the dewatering screen (2) is installed internally, and the sludge supplied to the filtration chamber (5) between the dewatering screen (2) and the screw shaft (4), In the screw press where the filtrate is separated from the dehydration screen (2) while being transferred by the screw blade (3) and the dehydrated cake is taken out from the end of the filtration chamber (5), A pair of disk-shaped concentrating screens (11, 11) are provided, and an annular concentrating chamber (13) is formed on the outer periphery of the concentrating screen (11) to form an annular concentrating chamber (13). An impeller (7) is disposed in the chamber (13) to constitute a concentrator (8), and a feed sludge supply port (14) and an impeller boss of the impeller (7) are provided in the outer ring (12) of the filter chamber. Open the sludge supply hole (23 ...) of concentrated sludge in (20) Concentrated mechanism with screw press, characterized in that is projected to the inside of the screen provided inside the screw shaft (2) (4) a blade boss (20).   The screw press with a concentrating mechanism according to claim 1, wherein an impeller (21) of an impeller (7) disposed in the concentrator (8) is bent in a rotating direction.   The screw press with a concentrating mechanism according to claim 1 or 2, wherein the impeller (7) is rotated in the same direction as the rotation of the screw blade (3) of the screw press (6).   A plurality of sludge supply ports (14a, 14b) are opened in the filter outer ring (12), and the impeller (21 ...) of the impeller (7) is bent toward the front and back surfaces of the blade surface. 4. The screw press with a concentrating mechanism according to claim 1, wherein the raw liquid sludge is press-fitted.   5. The screw press with a concentrating mechanism according to claim 1, wherein a notch groove (22) is provided at the tip of the impeller (21) of the impeller (7).   The screw press with a concentrating mechanism according to any one of claims 1 to 5, wherein a plurality of communication holes (26 ...) are provided on a blade surface of an impeller (21) of the impeller (7).   The concentration screen (11) is composed of a plurality of concentric annular divided metal filter media (11a, 11b, 11c), and the fine holes of the divided metal filter media (11a, 11b, 11c) are directed from the circumference toward the center. The screw press with a concentration mechanism according to claim 1, wherein the screw press is reduced in stages.