JP2004089863A - Centrifugal separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize enhancement of a separation performance of a lateral centrifugal separator, energy-saving and cost reduction and to excellently discharge a consolidated heavy component. <P>SOLUTION: In the centrifugal separator, a screw conveyor is accommodated at the inside of bowl 1 rotating at high speed. The bowl 1 has a horizontal cylindrical shape and a discharge port 7 for a separation liquid C is provided on an outer peripheral part at a rear end wall 3. A suppression ring 21 is projected at a front inner periphery of the bowl 1 provided with a sludge discharge port 6. A feed port 15 for a raw liquid a is provided on a rear part of a rotation body 11 of the screw conveyor 10 and a suppression flange 23 is projected on a front part of the rotation body 11 toward the suppression ring 21. A narrow delivery passage 20 for the heavy component (b) is formed between the ring 21 and the flange 23. A scraping member 25a is projectedly provided on the flange 23 and even the consolidated heavy component having high deposition property can be always scraped off and peeled off. Thereby, the heavy component b receives an action such as pressurization, extrusion, squeezing or the like, a solid/liquid separation efficiency is outstandingly enhanced and discharge of the heavy component is smoothly carried out. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a straight-body centrifugal separator in which concentration, dehydration, collection of solid matter and separated water of sewage sludge and industrial wastewater are performed by centrifugal force.
[0002]
[Prior art]
Conventionally, a decanter-type centrifugal separator is generally used for solid-liquid separation of sludge and the like. As shown in FIG. 11, this separating device is formed by connecting a conical cylinder 41 to the end of a horizontally long straight body 40 and forming a high-speed rotating bowl (outer rotating cylinder) 1 in an inner cylinder (inner rotating cylinder). A screw conveyer 10 having a spiral blade 12 provided on 11 and rotating with a relative speed difference from the bowl 1 is accommodated, and a stock solution a such as sludge is supplied from the inner cylinder 11 into the front and rear central portions of the bowl 1 and solidified by centrifugal force. It performs liquid separation. The heavy component b sedimented and separated by the centrifugal force in the bowl 1 is sequentially raked toward the front end by the spiral blade 12, and further subjected to the consolidation and dewatering action in the conical cylinder 41, thereby causing The separated liquid c is discharged out of the apparatus through the discharge port 6, and the separated liquid c overflows through a discharge hole 42 provided in the rear end wall 3 of the bowl 1 on the opposite side.
[0003]
In this decanter-type centrifugal separator, the heavy component is lifted to a level higher than the water level in the bowl by a conical portion called a beach in order to prevent the filtrate from flowing out of the drain port 6 for discharging the heavy component. In order to enhance the dewatering effect, a conical cylinder 41 whose front end is reduced in diameter to a level (water level) equal to or higher than the outlet 42 of the separated liquid is required.
[0004]
[Problems to be solved by the invention]
Decanter-type centrifugal separators have been developed for the concentration and dehydration of crystals and the like in a liquid layer. When used, the sludge settling tank is paste-like and strongly hydrophilic, and in order to enhance the solid-liquid separation performance, it is necessary to exert a strong consolidation effect so as to squeeze out water. In the above-mentioned conventional decanter-type centrifugal separator, when the undiluted solution a is supplied into the bowl 1, it is solid-liquid separated by a high centrifugal force field (about 2000 to 3000 G) in the bowl straight body portion 40 immediately after the supply. In the bowl conical portion 41 from which the heavy component b is discharged, since the distance (diameter) from the center of rotation is short, the phenomenon that the centrifugal force is weakened and the water content increases is seen. In fact, in the apparatus shown in FIG. 11, it has been observed that the water content is lowest near the boundary between the straight body portion 40 and the conical portion 41 and near the bowl wall far from the center of rotation. Furthermore, in order to discharge heavy components, it is necessary to raise the conical portion against strong centrifugal force, and even if it is attempted to transport it by a screw conveyor, if the water content is low, it will rotate around due to frictional resistance. However, there is a tendency that only heavy sludge having a relatively high water content close to the rotation center of the straight body portion 40 is discharged, while the heavy components remain and are not discharged.
[0005]
Further, since the heavy component b passes through a conical cylinder having a large inclination for discharging the water beyond the water level in the bowl, a slip occurs at this portion, and the discharge is deteriorated. There is a disadvantage that the separated liquid is discharged from the outlet 42 and becomes dirty. In addition, since the discharged heavy component b has a relatively high water content close to the rotation center of the straight body portion 41, the discharged heavy component b is reduced in order to lower the water content of the discharged heavy component. In reality, the engine is operated at an unnecessarily high rotational speed (about 2000 to 3000 rpm). Therefore, large power is required.
[0006]
Therefore, the present inventors proceeded with research to solve the above-mentioned problems in the decanter-type centrifugal separator, and made the entire bowl into a horizontally long cylindrical shape, and the front end of the bowl having the highest dewatering and compaction density. A straight-type centrifugal separator has been developed that allows heavy components to be extracted directly from the inner periphery through a narrow discharge path. This device has good separation efficiency, can reduce the number of rotations of the bowl, can save power, and can simplify and reduce the size of the device because it does not have a conical beach portion.
[0007]
By the way, stock solutions to be processed by this type of device have various properties. For example, in the case of an undiluted solution containing MAP (magnesium, ammonia, phosphorus), MAP is precipitated by the consolidation action, which is converted into an adhesive, and the condensed heavy component gradually adheres to the front end of the bowl having a narrow discharge passage. Then, it was found that there was a problem that the solidification was caused and the emission of heavy components was hindered.
[0008]
The present invention has been made in order to solve the problems in the straight-body centrifugal separator, scraping of heavy components attached to the suppression flange provided at the front end of the bowl or the inner periphery of the front end of the bowl, It is an object of the present invention to provide a centrifugal separator in which a separating means is provided to prevent heavy components from adhering and accumulating, thereby enabling smooth discharging of heavy components.
[0009]
[Means for Solving the Problems]
In the separation device of the present invention, the entire bowl has a horizontally long cylindrical shape. Thereby, the residence time of the heavy component can be extended, and the solid-liquid separation can be sufficiently performed. Further, in the apparatus of the present invention, a suppression ring for compacting the heavy component and a suppression collar opposed thereto are provided at the front end where the heavy component is discharged, and a narrow discharge path is formed between the two. From the inner periphery of the bowl with the highest density, heavy components can be transported through a narrow discharge path so that they can be taken out, regardless of the nature of the stock solution or heavy components, solid-liquid separation performance is improved, and heavy components with a stable concentration Is obtained. Then, in order to smoothly discharge the heavy components, a scraping member for constantly scraping and separating heavy components adhered and deposited by consolidation is provided on the back surface and / or the tapered surface of the suppression flange. In addition, the scraping member can be provided on the inner periphery of the front end of the bowl provided with the suppression ring, and furthermore, it can also be provided on the tapered surface of the suppression collar.
[0010]
Further, in the apparatus of the present invention, the discharge point of the filtrate can be provided on the peripheral wall at the rear of the bowl, and further, the scraping part for scraping off the sludge adhering to the filtrate discharge part provided on the peripheral wall of the bowl is provided. Wings may be provided.
[0011]
Further, in the apparatus of the present invention, the bowl may not be a straight body as shown in the figure, but may have a larger diameter at the front end (discharge side) than at the rear end. For example, a conical cylindrical shape, a cylindrical shape gradually increasing in diameter, or the like can be applied.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of the apparatus of the present invention, FIGS. 3 to 6 show other embodiments of the heavy component discharge section, and FIGS. 7 to 10 show other embodiments of the separation liquid discharge section. It shows an embodiment.
[0013]
In FIGS. 1 and 2, reference numeral 1 denotes a high-speed rotating bowl (outer rotating cylinder) having a horizontal cylindrical shape, and hollow shafts 4 and 5 projecting from the center of both front and rear end walls 2 and 3. It is supported by bearings (not shown) and is rotated at a high speed by a driving device. On the peripheral wall at the front end of the bowl 1, a plurality of mud holes 6 are provided along the circumferential direction, and on the rear end wall 3 of the bowl 1, an outlet 7 for the separated liquid is provided. I have. The outlet 7 is not shown, for example, but a plurality of fan-shaped outlets may be circumferentially spaced or a number of small holes may be spaced along the outer peripheral portion of the rear end wall 3. .
[0014]
Reference numeral 10 denotes a screw conveyor accommodated in the bowl 1, and a spiral wing 12 is wound around the outer periphery of a rotary drum 11, and both ends thereof are supported by the protruding portions of the hollow shafts 4, 5 of the bowl 1 in the bowl. The bowl 1 is rotated with a required speed difference by a rotating shaft 13 inserted through the hollow shaft 4. A supply chamber 14 for the undiluted solution a is provided in the rear part of the rotating drum 11, and a supply port 15 communicating with the annular space 8 between the bowl 1 and the rotating drum 11 is formed on the peripheral wall thereof. A supply pipe 16 for the undiluted solution inserted through the rear central shaft 5 of the bowl 1 is provided to open to the supply chamber 14.
[0015]
In the front end of the bowl 1, there is provided an annular narrow discharge path 20 which is short in the axial direction and applies a compaction effect to the heavy component b conveyed in the annular space 8 to discharge the heavy component b. In other words, on the inner periphery immediately before the mud hole 6 provided at the front end of the bowl 1 (left side in FIG. 1), a tapered cross-sectionally substantially mountain-shaped suppressing ring 21 having a tapered surface 22 on the rear side is provided inward. It is projected toward. At the front end of the rotating drum 11 of the screw conveyor 10, a suppression flange 23 that forms an annular discharge path 20 between the suppression ring 21 and the suppression ring 21 projects radially outward at a position facing the suppression ring 21. It is provided.
[0016]
As shown in FIG. 2, the suppression flange 23 is formed in a ring-shaped member, is inserted into the rotating body 11, and is detachably provided by a bolt (not shown) or the like. Further, as shown in the drawing, the surface of the suppression collar 23 facing the tapered surface 22 of the suppression ring 21 is formed in a tapered cross section having a tapered surface 24 that is substantially parallel to the surface 22, so that the two surfaces 21 are formed. , 23, a narrow discharge passage 20 communicating with the inner periphery of the bowl 1 is formed. The suppression flange 23 has at least one or more scraping members 25a protruding from an outer peripheral portion of a back surface (a surface facing the rear end wall 3). When a plurality of scraping members 25a are provided, they are preferably provided at substantially equal intervals. The number of the scraping members 25a can be appropriately increased or decreased according to the properties of the stock solution or the like. In the examples of FIGS. 1 and 2, the scraping member 25 a has a plate shape. However, the scraping member 25 a may be a block shape, and the scraping member 25 a is formed integrally with the suppression flange 23. You can also.
[0017]
In the above-described apparatus, the stock solution a to be processed enters the supply chamber 14 from the supply pipe 16 as shown by the arrow, is supplied into the annular space 8 from the supply port 15, and is separated into solid and liquid by centrifugal force due to the rotation of the bowl 1. The spiral blade 12 conveys the paper toward the front end. Then, the separated liquid C, which is the separated liquid, is discharged out of the machine through the discharge hole 7 in the rear end wall.
[0018]
The heavy component b including the solid content and the liquid content is swept toward the front end of the bowl 1 by the spiral blade 12 and further subjected to a separating action by centrifugal force, whereby the separation of the remaining liquid proceeds, and the separation is performed. The liquid C is also discharged from the discharge hole 7. The heavy component b conveyed to the front of the bowl 1 is condensed by a suppression ring 21 protruding at the front end of the bowl 1 and a suppression flange 23 protruding at the front of the rotating drum 11 and has a narrow discharge path. 20 and further conveyed through the discharge passage 20 by the spiral wing 25 rotating with the rotation of the suppression collar 23 while being further compacted, and exiting from the tip thereof and going out of the mud outlet 6 as shown by an arrow. Will be leaked. Then, in the apparatus of the present invention, the scraping member 25a protruding from the suppression flange 23 rotates at a high speed together with the suppression flange 23 to constantly scrape heavy components that adhere and accumulate, so that the heavy components can be discharged smoothly. Will be done.
[0019]
FIG. 3 shows another embodiment of a portion provided with a suppression ring 21 and a suppression flange 23 which are discharge portions of the heavy component b. In this embodiment, the scraping member 25 b protrudes from the tapered surface 24 of the suppression flange so as to project into the discharge path 20. The scraping member 25b is preferably protruded at an angle to the axis as shown in the drawing so as to push the heavy component pushed into the discharge path 20 toward the front end while scraping the heavy component. Thereby, the flow of the main component in the discharge path 20 can be improved and clogging can be eliminated.
[0020]
FIG. 4 shows an embodiment in which a scraping blade 25a is projected from the back surface of the suppression flange 23 and a scraping member 25b is also projected from the tapered surface 24. In this way, heavy components having particularly high adhesion can be discharged favorably.
[0021]
FIG. 5 shows still another embodiment of the portion where the suppression ring 21 is provided. In this embodiment, the scraping member 25c is provided to protrude toward the bowl 1. That is, at least one or more scraping members 25 c are provided on the inner periphery of the bowl 1 near the connection with the suppression ring 21 so as to protrude into the annular space 8. In this case, since the bowl 1 and the rotary drum 1 are rotated with a relative speed difference, it is effective in scraping heavy components near the entrance of the discharge path 20 and heavy components attached to the back surface of the suppression collar 23. Further, in this case, as shown in FIG. 6, in addition to the scraping member 25c, as shown in FIG. The combined use of 25c and 25b can further enhance the scraping effect.
[0022]
Further, in the apparatus of the present invention, a place for discharging the filtrate may be provided on the peripheral wall of the bowl 1. 7 and 8 show the embodiment. In this embodiment, a discharge port is not provided in the rear end wall 3, and a discharge part 30 for filtrate is provided in the peripheral wall at the rear part of the bowl 1 instead. As shown in FIG. 8, a large number of discharge holes 31 formed in the circumferential direction, and a screen formed of a porous plastic molded body, a metal net, a sintered body of ceramics and metal, a filter cloth, etc. for filtering solid components inside the discharge holes 31. 32 is additionally provided. Note that the structure of the filtrate discharge section 30 is not limited to the above-described structure, and the structure can be appropriately changed as long as it is a combination of the discharge hole 31 and the screen 32. As described above, in the case where the discharge point of the filtrate is provided on the peripheral wall of the bowl 1, the separated liquid C is discharged immediately after the supply of the undiluted solution, so that almost no water surface is generated in the bowl 1, Therefore, solid-liquid separation and dehydration are performed more efficiently.
[0023]
Further, in the apparatus of the present invention, as shown in FIG. 9, the filtrate discharge point is provided on the bowl rear end wall 3 as in the embodiment of FIG. 1 and the peripheral wall of the bowl 1 as in the embodiment of FIG. It can be provided. That is, the discharge port 7 is provided on the rear end wall, and the filtrate discharge section 30 is provided on the peripheral wall of the bowl. In this way, the separation liquid C is discharged from both the discharge port 7 and the filtrate discharge part 30, so that the processing of a stock solution with a low concentration and the processing with high efficiency even under a high load can be performed.
[0024]
FIG. 10 shows an embodiment in which means for scraping sludge adhering to the filtrate discharge unit 30 is provided. That is, in this embodiment, a part of the spiral blade 12 is cut out toward the screw conveyer 10 corresponding to the filtrate discharge part 30, and the tip of the spiral blade 12 is slidably contacted with the screen 32 at that part. A plurality of sludge scrapers 33 attached to the screen 32 are radially mounted. The scraper blade 33 not only scrapes the sludge attached to the screen 32 but also keeps an angle with respect to the axis so as to have a conveying force for the sludge and the dewatered cake. Is preferred. Further, in this embodiment, the outlet 7 is provided in the rear end wall 3 of the bowl 1, but the outlet 7 may not be provided.
[0025]
The scraping of the sludge adhering to the screen 32 of the filtrate discharge part 30 can be performed to some extent by the spiral blade 12 of the screw conveyor 10. However, since there is some clearance between the spiral blade 12 and the inner surface of the screen 32 and the difference in the rotation speed between the bowl 1 and the screw conveyor 10 is small, the scraping by the spiral blade 12 cannot be performed. Since the sludge is slow, the sludge is not sufficiently scraped off, and the screen 32 is clogged, and discharge of the separated water is deteriorated. Therefore, in the apparatus of this embodiment, the scraper blades 33 that are in sliding contact with the screen 32 are provided so that the sludge can be scraped positively.
[0026]
In each of the above devices, the shape of the bowl 1 is a simple oblong cylinder having the same diameter over the entire length, but the shape of the bowl 1 applied to the device of the present invention is not limited to this. For example, although not shown in the drawings, the bowl 1 may have a horizontally long conical cylindrical shape whose diameter gradually increases from the rear end side to the front end side, or a required length portion at the rear end side may be a cylindrical straight body. Subsequently, a conical body with a large diameter at the front end is formed by extension, or a required length portion at the rear end is formed into a cylindrical straight body, and then a short cone that expands forward. It is also possible to apply a bowl-shaped body with an enlarged diameter at the tip side of the bowl 1 from which heavy components are discharged, such as by extending a cylindrical body with a large diameter and extending the cylindrical body. Can be.
[0027]
【The invention's effect】
As described above, according to the centrifugal separator of the present invention, the filtrate (separated liquid) discharge portion is provided on the peripheral wall at the rear portion of the bowl or the outer peripheral portion of the rear end wall, and the undiluted solution is discharged through the filtrate discharge portion (discharged liquid). Hole), a suppression ring and a suppression collar are provided opposite the front end of the bowl and the front end of the rotary cylinder of the screw conveyor, and a narrow discharge path is provided between the two. Since the scraping member is protruded from the flange or the inner periphery of the front end of the bowl, or both, a number of excellent effects are achieved as follows.
[0028]
(1) The bowl has a horizontal cylindrical shape, and a suppression ring and a suppression collar are provided at the heavy component discharge part, eliminating the need for a long conical cylinder with a long slope and a large throttle unlike the conventional machine. In addition, it is possible to smoothly transport and discharge heavy components having a low water content.
[0029]
(2) At the front end of the bowl, the heavy component is subjected to a consolidation action by the suppression ring and the suppression collar, and is further pushed out by passing through the narrow discharge path formed by the suppression ring and the suppression flange, and is subjected to the throttle action. As a result, the solid-liquid separation efficiency is greatly improved. In addition, since the spiral path is provided in the discharge path, even highly dehydrated heavy components can be smoothly discharged.
[0030]
(3) Even in the treatment of a stock solution in which heavy components adhere to the front end of the bowl having the discharge path, the scraping member can scrape the solution, so that it can be widely applied to the treatment of stock solutions having various properties. In addition, the discharge of heavy components can be performed smoothly and well.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing an embodiment of the apparatus of the present invention.
FIGS. 2A and 2B show the suppression flange portion, wherein FIG. 2A is a side sectional view and FIG. 2B is a rear view.
FIGS. 3A and 3B show another embodiment of the suppression collar portion, wherein FIG. 3A is a side sectional view and FIG. 3B is a front view.
FIGS. 4A and 4B show still another embodiment of the suppressing collar portion, wherein FIG. 4A is a side sectional view and FIG. 4B is a front view.
FIG. 5 is a side sectional view showing another embodiment of a portion provided with a suppression ring.
FIG. 6 is a side sectional view showing still another embodiment.
FIG. 7 is a side sectional view showing another embodiment of the filtrate discharge part.
FIG. 8 is an enlarged side sectional view of a filtrate discharge part.
FIG. 9 is a side sectional view showing still another embodiment of the filtrate discharge part.
FIG. 10 shows still another embodiment.
FIG. 11 is a side sectional view showing a conventional decanter-type apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bowl 2 Front end wall 3 Rear end wall 6 Drainage port 7 Drainage of filtrate 8 Annular space Screw conveyor rotating drum 12 Spiral blade 14 Supply chamber 15 Supply port 16 Supply pipe discharge path 21 Suppression ring 22 Tapered surface 23 Suppression collar 24 Taper Surfaces 25a, 25b, 25c Scraping member 30 Filtrate discharge unit 31 Discharge hole 32 Screen scraping blade

Claims (5)

A screw conveyor that rotates with a relative speed difference is accommodated in a bowl that rotates at high speed, and heavy components are separated and settled by centrifugal force from the stock solution supplied into the rotating bowl, and this is conveyed to the front end of the bowl by the screw conveyor. In a centrifugal separator that transfers and discharges the liquid to a bowl, the bowl is formed into a horizontal cylindrical shape, a discharge hole for the separated liquid is provided in the rear end wall of the bowl, and the inner periphery of the front end of the bowl is compacted with heavy components. In addition to projecting a suppression ring that gives an effect, a suppression flange is provided at the front end of the rotating drum of the screw conveyor so as to face the suppression ring, and a weight is formed between the inner periphery of the suppression ring and the outer periphery of the suppression flange. A centrifugal separator, wherein a discharge path for the components is formed, and a scraping member for preventing the adhesion of heavy components is protrudingly provided on the back surface of the suppression flange. 2. The centrifugal separator according to claim 1, wherein the scraping member is provided on the tapered surface facing the suppression ring of the suppression flange instead of the back surface of the suppression flange. 2. The centrifugal separator according to claim 1, wherein the scraping member protrudes from both the back surface and the tapered surface of the suppression collar. 2. The centrifugal separator according to claim 1, wherein the scraping member is replaced with a suppression collar, and protrudes from an inner periphery of a front end of a bowl connected to the suppression ring. 3. The centrifugal separator according to claim 2, wherein the scraping member protrudes from the tapered surface of the suppression flange and the inner periphery of the front end of the bowl.

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