JP4493031B2 - Filtration device - Google Patents

Description

  The present invention relates to a filtration device.

Filter materials such as metal screens, nets, and perforated plates are superior in terms of operability, maintainability, durability, etc. compared to cloth (fiber) materials. There is a pressure filtration device such as a rotary pressure dehydrator. This device has a long history and has a very simple structure, so it features low power, low noise, low cost, etc., and even when applied to a hard-to-dehydrate solid-liquid mixture with a low solid content. Since excellent dewatering performance is obtained, it is often used in the field of sewage sludge dewatering (see, for example, Patent Documents 1 and 2).
However, in a screw press comprising a cylindrical outer filter medium and a screw inserted therein, the liquid to be treated is transferred from the inlet side to the outlet side at a low speed, and at the same time, generated by the tightening force of the screw. Although it is continuously dehydrated by the pressing pressure, since the filtrate is squeezed out only from the outer filter medium, it is difficult to shorten the length of the outer filter medium, and it is difficult to downsize the equipment.
On the other hand, in the rotary pressurization type dehydrator, it is necessary to increase the diameter of the disk or to arrange a plurality of dehydrators in order to improve the throughput of dehydration filtration. It was.
Therefore, in view of such problems, the present inventors provide a concentrically arranged cylindrical or conical inner filter medium and outer filter medium, and a filtration space between these inner filter medium and outer filter medium. A spiral-shaped partition, and a liquid to be treated is fed from the lower side of the filtration space, the cake is discharged from the upper side of the filtration space, and the filtrate that has passed through the inner and outer filter media is removed. A filtering device configured to discharge to the outside has been proposed in which the inner filter medium and / or the outer filter medium rotate around the axis, and the spiral partition does not rotate (for example, Patent Document 3). .
JP 2001-212697 A JP 2001-113109 A Japanese Patent Application No. 2005-176901

In the above invention, the device itself can be reduced in size and the dehydration performance can be improved, but it is desired to efficiently scrape off the cake adhered to the surface of the filter medium and further improve the filtration concentration performance. Yes.
Then, the main subject of this invention is providing the filtration apparatus which improves filtration concentration performance.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
A concentric arrangement of cylindrical or conical inner and outer filter media;
A spiral partition provided in a filtration space between the inner filter medium and the outer filter medium,
The axis is vertically oriented and the entire device is vertically oriented,
A configuration in which the liquid to be treated is fed upward from below the filtration space, the cake is discharged from the upper side in the filtration space, and the filtrate that has passed through the inner filter medium and the outer filter medium is discharged to the outside. A filtration device of
The inner filter medium and the outer filter medium rotate around an axis, the spiral partition is configured not to rotate, and the cake is raised along the partition by a frictional force with the rotating filter medium, and the filtration space Configured to be discharged from
Each of the inner filter material and said outer filtration scraping cake adhering to the material scraper, so as to be close to or in contact with the filtering surface, in the axial direction of the inner filter material and the outer filter media, and the inner peripheral edge of the partition of the spiral Provided in the filtration space along the outer periphery,
A filtering device characterized by that.

(Function and effect)
By performing filtration and concentration with two surfaces of the inner filter medium and the outer filter medium, it is possible to reduce the size of the equipment as compared with a screw press that performs filtration only with a conventional outer filter medium. In addition, the inner filter medium and / or the outer filter medium rotate around the axis and the spiral partition does not rotate, so that the liquid to be treated fed into the filtration space is spirally installed along the partition. While moving inside, first, filtration and concentration by the two sides of the inner and outer filter media is performed, and then press dewatering is performed, but not only the inner and outer filter media but also the ribbon screw, all of which are configured to be freely rotatable compared to the screw press The filtration device according to the present invention can simplify the structure, and can reduce the manufacturing cost and improve the maintainability.
In addition, a scraper that scrapes the cake adhering to the filter medium is provided in the axial direction of the inner filter medium and the outer filter medium, and along the inner peripheral edge and the outer peripheral edge of the spiral partition so as to approach or contact the filter surface. As a result, the cake adhered to the filtration surface can be efficiently scraped off, and the filtration concentration performance can be remarkably improved.
Depending on the properties of the cake, the degree of progress of dehydration and the design of the filter chamber volume may not be balanced, and the cake filling rate may decrease. In this case, in the configuration in which the filtration device is arranged sideways (horizontal type), the filtrate is affected by gravity and leaches into a cake having a low filling rate, so that the moisture content of the discharged cake is increased. is there. Accordingly, the axial center is vertically oriented, the entire apparatus is vertically oriented, and the liquid to be treated is fed upward using gravity by being configured so that the liquid to be treated is fed in a pressurized state from below to above. It is possible to prevent the cake from being leached to the cake discharge side, and therefore, it is possible to eliminate unevenness (distribution) of the moisture content of the discharged cake and make it more uniform.

<Invention of Claim 2>
The filtration device according to claim 1, wherein the scraper at least in the vicinity of the upper side of the filtration space is disposed so as to be positioned in a tangential direction of the inner filter medium and the outer filter medium.

(Function and effect)
By placing the scraper at least near the upper side of the filtration space so as to be positioned in the tangential direction of the inner and outer filter media, the resistance is reduced in the cake discharge side portion of the filtration space where there are many cakes with reduced moisture content. This makes it easier to transport the cake.

<Invention of Claim 3>
At least the scraper in the vicinity of the lower side of the filtration space is close to or in contact with the filtration surface, and the tip surface facing the cake conveyance direction is directed from the rear to the front in the cake conveyance direction, and the spiral of the partition The filtration device according to claim 1, wherein the filtration device is disposed at a swing angle with respect to a tangential direction of the inner filter medium and the outer filter medium, which is provided so as to be directed toward a center portion in a width direction of the belt-like band .

(Function and effect)
Tangential lines of the inner and outer filter media so that the scraper at least near the lower side of the filtration space is directed from the front end portion close to or in contact with the filtration surface to the center portion in the width direction of the spiral strip of the partition. By arranging with a swing angle with respect to the direction, in the feeding part of the filtration space where the cake concentration is low and the liquid to be treated has a lot of fluidity, the cake can be efficiently conveyed while being stirred, Uniformity of the concentration and pressure distribution of the liquid to be treated can be further promoted.

<Invention of Claim 4 >
The filtration device according to claim 4, wherein incisions along the width direction are formed at intervals in the vertical direction on a front end surface of a scraper facing the cake conveying direction .

(Function and effect)
By forming cuts along the width direction and at intervals in the longitudinal direction on the tip surface of the scraper facing the cake transport direction , turbulence is generated at the cut portions, and the peeled cake is further stirred. be able to.

<Invention of Claim 5 >
The scraper, the surface adjacent to or in contact with the filtering surface is the disposed so as to be located at the inner periphery and outer periphery respectively substantially the same on the circumference of the partition, any one of claims 1 to 4 The filtration device described.

(Function and effect)
By providing the side surface close to or in contact with the filtration surface of the scraper on the same circumference as the inner and outer edges of the partition, the distance between the inner filter medium and the outer filter medium and the partition can be increased. Since it is not necessary to provide extra space for the thickness of the scraper, the intervals between the inner filter medium and the outer filter medium and the partition can be reduced, and the filtration concentration performance and the dewatering performance can be improved.

<Invention of Claim 6 >
The filtration device according to any one of claims 1 to 5 , wherein the scraper is fixed on a lower side and an upper side of the filtration space.

<Invention of Claim 7 >
The filtration device according to any one of claims 1 to 5 , wherein the scraper is fixed by connecting either the lower side or the upper side of the filtration space and the peripheral edge of the partition.

<Invention of Claim 8 >
The filtration device according to any one of claims 1 to 5 , wherein the scraper is fixed by connecting peripheral edges of the partition.

<Invention of Claim 9 >
The filtration device according to any one of claims 1 to 5 , wherein the scraper is fixed only to either the lower side or the upper side of the filtration space.

(Function and effect)
By fixing the scraper to the lower side and the upper side of the filtration space, the scraper is firmly supported. Also, either the lower side or upper side of the filtration space and the peripheral edge of the partition are connected and fixed, the peripheral edges of the partition are connected and fixed, or either the lower side or upper side of the filtration space. By fixing to only one side, the arrangement form of the scraper can be suitably changed at the upper part or lower part of the filtration space.

<Invention of Claim 10 >
The filtration device according to any one of claims 1 to 9 , wherein at least an inner peripheral edge and an outer peripheral edge of the spiral partition on the inlet side of the liquid to be processed are close to or in contact with the inner filter medium and the outer filter medium, respectively. .

(Function and effect)
Since the liquid to be processed sent into the filtration space has a low cake concentration and fluidity, filtration and concentration are caused by the inner and outer filter media in the vicinity of the inlet side of the liquid to be processed. Therefore, in the vicinity of the inlet side of the liquid to be processed, filtration and concentration by solid-liquid separation is an important function, but at least the inner peripheral edge and the outer peripheral edge on the inlet side of the liquid to be processed are respectively connected to the inner side of the spiral partition. By setting it as the structure which adjoins or contacts a filter medium and an outer side filter medium, the cake adhering to the filtration surface of a filter medium is scraped off, and the efficiency of filtration concentration can be maintained. In addition, the fed liquid to be processed can be spirally moved along the partition.

<Invention of Claim 11 >
The filtration device according to any one of claims 1 to 10 , wherein a rotation speed of the inner filter medium and a rotation speed of the outer filter medium are rotatable with a speed difference.

(Function and effect)
When the rotation speed of the inner filter medium and the rotation speed of the outer filter medium rotate with a speed difference, a shearing force is generated in the cake moving in the filtration space. Therefore, for example, for a liquid to be treated containing raw sludge having a high fiber content or mixed raw sludge, the dewatering efficiency can be improved by this shearing force. In addition, when the relative speed of each of the inner and outer filter media is large, the cake in the vicinity of the rapidly rotating filter surface (for example, the filter surface of the inner filter media) moves to the other filter surface (for example, the filter surface of the outer filter media). The effect appears and the mixing action in the cake occurs, so that the moisture content distribution in the filtration device can be made uniform.

<Invention of Claim 12 >
The inner filter medium is provided with a first rotation drive means, the outer filter medium is provided with a second rotation drive means, and the first rotation drive means and the second rotation drive means are separate from the rotation drive means. The filtration device according to any one of claims 1 to 11 , wherein

(Function and effect)
It is possible to improve the dewatering efficiency by applying shear force to the cake due to the difference in rotation speed between the inner and outer filter media, but this effect depends on the properties of the target cake. It is necessary to set the speed difference between the inside and outside. In the present invention, the difference in speed between the inside and outside can be easily adjusted in accordance with the cake properties by using a rotation driving means different from the first rotation driving means and the second rotation driving means.

<Invention of Claim 13 >
The filtration device according to any one of claims 1 to 12 , wherein the spiral partition is configured such that a pitch interval is shortened from the lower side toward the upper side .

(Function and effect)
The spiral partition is configured so that the pitch interval is shortened from the lower side of the filtration space to the upper side thereof, thereby narrowing the cake discharge path and enhancing the squeezing effect. It is possible to eliminate the unevenness (distribution) of the moisture content of the water and make it uniform.

  According to the present invention, there are advantages such as being able to improve the filtration concentration performance.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
<Configuration of filtration device according to the present invention>
As shown in FIG. 1 and FIG. 2, an inner cylinder rotating shaft to which a driving force is transmitted by a first rotation driving means (not shown) such as a motor is disposed inside the casing 7 in the filtration device according to the present invention. 5, a rotatable cylindrical inner filter medium 1 having an upper plate 1A connected thereto, a rotatable cylindrical outer filter medium 2 disposed concentrically with the inner filter medium 1, an upper plate 7A of the casing 7 and Both ends are fixed to the bottom plate 7B, and a spiral (ribbon screw) partition 3 disposed in a filtration space 4 formed between the inner filter medium 1 and the outer filter medium 2 is provided. In addition, although the casing 7 is a cylindrical shape in this Embodiment, it is not restricted to this, Shapes, such as a polyhedron, may be sufficient.

As shown in FIG. 2, to-be-processed liquid inlets 10 and 11 are formed in a portion of the bottom plate 7 </ b> B of the casing 7 that projects the filtration space 4. Is sent in. The liquid to be treated is pumped by a pump (not shown), and rises from the bottom to the top of the casing 7 together with this pressure by friction caused by the rotation of the inner filter medium 1 and the outer filter medium 2 . Also the liquid to be treated feed inlet is a two positions in the present embodiment, may be formed of one or more is not limited thereto.

  On the side surface (outer peripheral surface) of the inner filter medium 1, a wedge wire is stretched as a filter medium, and the slits of the wedge wire are arranged along the rotation axis. Of the liquid to be treated that is fed into the filtration space 4 formed between the inner filter medium 1 and the outer filter medium 2, a part of the filtrate that has undergone solid-liquid separation is transferred to the bottom plate 7 </ b> B of the casing 7 in the inner filter medium 1. It is accumulated and finally discharged from the filtrate outlet 12.

  The outer filter medium 2 has a structure in which the upper end of the outer periphery is suspended from the upper plate 7A of the casing 7 by a rail and a roller guided by the rail, and the side surface of the upper end is not shown. The outer filter medium 2 itself is connected to an outer rotation shaft (not shown) to which a driving force is transmitted by a second rotation driving means (not shown) such as a motor via a pinion gear (not shown). It is designed to rotate. Further, similarly to the inner filter medium 1, a wedge wire is stretched as a filter medium on the inner peripheral surface of the outer filter medium 2. The slits of this wedge wire are arranged along the rotational axis, and of the liquid to be treated that is fed into the filtration space 4, a part of the filtrate that has undergone solid-liquid separation is formed between the casing 7 and the outer filter medium 2. It is stored in the bottom plate 7B in the middle portion and finally discharged from the filtrate discharge port 13.

  Here, even when the inner filter medium 1 and the outer filter medium 2 are rotated at the same angular velocity (° / sec), the peripheral speed (mm / sec) of each radial difference is generated, so that shear force is generated in the cake. Thus, dewatering efficiency is improved. For example, for the liquid to be treated containing raw sludge having a high fiber content or mixed raw sludge, since this shear force is more effective, a slight speed difference is given to the inner filter medium 1 and the outer filter medium 2, By rotating it, it is possible to further improve the dehydration efficiency. Moreover, when the relative speed of the inner side filter medium 1 and the outer side filter medium 2 is large, the cake in the vicinity of the filtration surface (for example, the filtration surface of the inner filter medium 1) that rotates rapidly is the other filtration surface (for example, filtration of the outer filter medium 2). The effect of migrating to the surface) side appears, and the mixing action in the cake occurs, so that the moisture content distribution in the filtration device can be made uniform.

  As described above, the shearing force is applied to the cake due to the difference in angular velocity between the filtration surfaces of the inner and outer filter media 1 and 2, and the dewatering efficiency is improved. However, this effect depends on the properties of the target cake, so that it operates in an optimum state. In this case, it is desirable to set the speed difference between the inside and outside according to the cake properties. For this reason, in this embodiment, the inner and outer filter media 1, 2 are provided with rotational drive means such as individual motors so that the speed difference can be easily adjusted.

  On the other hand, depending on the cake properties, when a shearing force is applied, the cake may be fluidized, and conversely, the dewaterability may be impaired. In such a case, it is preferable to rotate the cake at a constant speed difference. In addition, for cakes that have a dehydration effect due to shearing force and the cake properties hardly change throughout the year, they may be rotated at a constant speed difference. May be rotated at the same speed by a single motor.

  The inner filter medium 1 and the outer filter medium 2 do not necessarily need to be rotated, and only one of them may be rotated.

  The filter medium used for the inner and outer filter media 1 and 2 is not limited to the wedge wire, and a punched plate (not shown), a wire mesh (not shown), a filter cloth (not shown), or the like can be used. . In addition, a wedge wire with a high opening ratio of the filtration surface at the lower part of the filtration space 4 where solid-liquid separation is main, and a contact area with the cake is high at the upper part of the filtration space 4 where compression dehydration is main (low opening ratio). A punched plate may be arranged.

  As shown in FIGS. 1 and 4, the partition 3 has a spiral shape (ribbon screw shape), and is disposed in an annular filtration space 4 formed between the inner filter medium 1 and the outer filter medium 2. . The partition 3 is fixed to the upper plate 7A and the bottom plate 7B of the casing 7, so that the partition 3 does not rotate around the axis. As a result, the filtration device according to the present invention can simplify the structure, reduce the manufacturing cost, and improve the maintainability, compared to a screw press that can rotate not only the inner and outer filter media but also the ribbon screw. Can be achieved.

  The inner peripheral edge and the outer peripheral edge of the partition 3 are configured to be close to or in contact with the filtration surfaces of the inner filter medium 1 and the outer filter medium 2, respectively. With this configuration, the cake adhered to the filtration surfaces of the inner and outer filter media 1 and 2 can be easily scraped off, the efficiency of filtration and concentration can be maintained, and the treatment object fed from the treatment liquid inlets 10 and 11 can be maintained. The liquid can be raised spirally along the partition 3. Since the lower part of the filtration space 4, that is, the vicinity of the liquid inlets 10 and 11 to be treated is mainly filtered and concentrated by the solid-liquid separation action, at least the inner edge and the outer edge of the partition 3 are at least of the liquid to be treated. It is sufficient if the vicinity of the inlets 10 and 11 is close to or in contact with the inner and outer filter media 1 and 2.

  Further, as shown in FIGS. 4 and 9, by attaching a scraper 16 formed of rubber or the like to the inner periphery and the outer periphery of the partition 3, the inner filter medium 1 and the outer filter medium 2 rotate around the axis, and the partition Since 3 is a structure which does not rotate, the cake supplemented by the filtration surface can be scraped off by this scraper 16. As described above, the lower portion of the filtration space 4, that is, the vicinity of the liquid inlets 10 and 11 to be processed mainly performs filtration and concentration due to the solid-liquid separation action. The scraper should just be attached to 11 side vicinity.

  The partition 3 may have a uniform spiral pitch throughout the filtration space 4, but in order to eliminate the unevenness (distribution) of the moisture content of the cake discharged, as shown in FIG. 1 and FIG. It is preferable to configure the partition 3 so that the pitch interval becomes shorter as it goes from the bottom plate 7B side of the casing 7 to the upper plate 7A side. Specifically, in the upper portion of the filtration space 4, the spiral pitch It is preferable to shorten the discharge path of the cake and shorten the cake discharge path to enhance the squeezing effect. On the other hand, as shown in FIGS. 5 to 8 to be described later, when the radius difference between the inner and outer filter media 1 and 2 is narrowed in order to improve the dewatering efficiency in the upper part of the filtration space 4, the spiral partition 3 is connected to the casing. 7 may be configured such that the pitch interval increases from the bottom plate 7B side to the upper plate 7A side.

  Although not shown, a hole through which the cake can pass can be formed in a part of the spiral blade to promote stirring and mixing of the cake. Further, the lower part of the partition 3 may be provided apart from the bottom plate 7B of the casing 7 in the lower part of the filtration space 4, that is, in the vicinity of the liquid inlets 10 and 11 to be processed (the lower part of the spiral blade may be cut). In this case, what is necessary is just to fix the partition 3 and the baseplate 7B of the casing 7 via arbitrary support members (for example, columnar member etc.).

  As shown in FIGS. 1, 4, and 9, the scraper 16 is arranged in the axial direction of the inner filter medium 1 and the outer filter medium 2 in the casing 7, so as to be close to or in contact with the filter surface, and the inner peripheral edge and the outer periphery of the partition 3. Both end portions are attached and fixed to the upper plate 7A and the bottom plate 7B of the casing 7 along the peripheral edge. That is, as shown in FIG. 9, scrapers 16 and 16 are provided so as to sandwich the opposite ends of the spiral band of the partition 3 in the width direction, and the inner filter medium 1 and the outer filter medium 2 are filtered. It is the structure which adjoins or contacts a surface. By this structure, the cake adhering to the filtration surfaces of the inner filter medium 1 and the outer filter medium 2 can be efficiently scraped, and the filtration concentration performance can be remarkably improved.

  Here, as shown in FIG. 9, since the scrapers 16 and 16 are disposed so as to be positioned in the tangential direction of the inner filter medium 1 and the outer filter medium 2, the conveyance resistance of the liquid to be processed and the cake to be conveyed is reduced. The peeling of the cake layer can be achieved without impairing the transportability. For this reason, especially by using the arrangement | positioning form shown in FIG. 9 for the upper part of the filtration space 4 with many cakes in which the moisture content fell, it can make resistance easy and can convey a cake.

  Moreover, the arrangement | positioning form shown in FIG. 10 can also be considered. The arrangement form shown in FIG. 10 is arranged so as to sandwich the opposite ends of the spiral band of the partition 3 in the width direction, but unlike the arrangement form shown in FIG. From the contacting part (front end part) to the rear end part, it is arranged with a slight swing angle from the tangential direction so as to guide the peeled cake to the central part of the transport path (partition 3). At this time, the space behind the scrapers 16 and 16 (wedge-like space) functions as a space that gives turbulent flow to the liquid to be treated and mixes it. For this reason, especially by using the arrangement | positioning form shown in FIG. 10 in the lower part of the filtration space 4 with many cake liquids with a low cake density | concentration and fluidity | liquidity, a cake can be efficiently conveyed, stirring. At the same time, it is possible to further promote the homogenization of the concentration and pressure distribution of the liquid to be treated.

  The arrangement forms shown in FIGS. 9 and 10 can be used in appropriate combinations. As described above, for example, the arrangement form shown in FIG. 10 is used for the lower portion of the filtration space 4 and the arrangement form shown in FIG. 9 is filtered. It can also be used in the upper part of the space 4. The scrapers 16 and 16 shown in FIGS. 9 and 10 do not necessarily have to be attached to face each other, and may be arranged to be staggered.

  Further, in place of the above-described scraper 16, as shown in FIG. 11, a scraper 21 in which the cross-sectional shape of the tip portion close to or in contact with the filtration surface is processed into a tapered shape can be proposed. By making the cross-sectional shape of the tip part tapered, it becomes easier to scrape the cake layer adhering to the filter medium (improvement of scraping effect), and the peeled cake is guided to the central part of the transport path (partition 3), so the cake Can be efficiently conveyed while stirring.

  Furthermore, as shown in FIG. 13, by making a plurality of incisions (for example, V-shaped incisions) in the width direction of the tip portion processed into a taper shape, turbulent flow is generated at the incised portion, and peeling is performed. The cake can be further stirred.

  Further, FIG. 12 shows an arrangement configuration in which the scraper 16 is attached so that the side surfaces of the scraper 16 that are close to or in contact with the filtration surface are located on the same circumference as the inner and outer edges of the partition 3. It is shown. This form can be realized, for example, by notching part of both end portions in the width direction of the partition 3 and attaching the scraper 16 having substantially the same arc side surfaces to the inner peripheral edge and the outer peripheral edge. In the form shown in FIG. 12, compared to the arrangement form shown in FIG. 9, the inner filter medium 1 and the outer filter medium 2 and the outer filter medium 2 need not be separated from the partition 3 by the thickness of the scraper 16. The space | interval of the filter medium 2 and the partition 3 can be narrowed, and filtration concentration performance and dehydration performance can be improved.

  About the fixing method of the scraper 16 (or 21), as mentioned above, it is the axial direction of the inner side filter medium 1 and the outer side filter medium 2 in the casing 7, and the inner periphery and outer periphery of the partition 3 so that it may adjoin or contact a filtration surface. Both ends of the casing 7 are attached to the upper plate 7A and the bottom plate 7B of the casing 7 along the peripheral edges, respectively, and in some cases, the peripheral edges of the partitions 3 adjacent in the axial direction are further connected so as to bridge each other. ing. However, the present invention is not limited to this, and as shown in FIG. 14, it is possible to fix by connecting only the peripheral edges of the partition 3 adjacent in the axial direction without fixing to the upper plate 7A and the bottom plate 7B of the casing 7. Good. Further, as shown in FIG. 15, either the upper plate 7A or the bottom plate 7B of the casing 7 and the peripheral edge of the partition 3 may be connected and fixed (in FIG. 15, the bottom plate 7B and the partition of the casing 7 are separated). 3 is fixed to the periphery). Furthermore, as shown in FIG. 16, it may be fixed to only one of the upper plate 7A and the bottom plate 7B of the casing 7 (in FIG. 16, it is fixed by the bottom plate 7B of the casing 7). Thus, by appropriately selecting the fixing method, the arrangement form of the scraper can be suitably changed in the upper part or lower part of the filtration space according to the properties of the liquid to be treated and the cake.

  One scraper 16 (or 21) is attached to each of the inner peripheral edge and the outer peripheral edge of the partition 3 in FIGS. 1, 2, 4 and the like, but it may be attached to a plurality of locations. Moreover, you may make it attach the scraper 16 (or 21) only to the lower part of the filtration space 4 by which solid-liquid separation is main.

  The above-described scraper 16 (or 21) is attached in parallel to the axial direction of the inner filter medium 1 and the outer filter medium 2, but is not limited to this. You may attach a scraper to each front-end | tip in a spiral shape so that a periphery may be followed.

  As described above, the scraper itself may be made of rubber, resin, or the like that can be pressed against the filtration surface by elastic force. However, as a modification, a spring is attached to the tip of the scraper. A blade having a function of making the blade movable in the radial direction of the inner filter medium 1 and the outer filter medium 2 by using a spring or the like can be used.

  Here, the relationship with the inner side filter medium 1, the outer side filter medium 2, and the partition 3 is demonstrated. The liquid to be processed fed from the liquid inlets 10 and 11 formed on the bottom plate 7B of the casing 7 which will be described later has a low cake concentration and fluidity. Filtration concentration occurs through the openings of the cylindrical filter media in the filter media 1 and the outer filter media 2. In the lower part of the filtration space 4, filtration concentration by solid-liquid separation action is an important function. However, when the filtration concentration progresses to some extent, the concentrated cake adheres to the filtration surface and the filtration efficiency decreases. Therefore, in order to maintain the concentration efficiency, the scraper 16 is attached to the partition 3, and the surface of the filter medium in the inner filter medium 1 and the outer filter medium 2 is scraped frequently, thereby scraping the cake adhered to the surface.

  Moreover, since the cake which lost fluidity | liquidity by the concentration effect | action produces a frictional force with a filter medium, it is conveyed by the rotating filter medium in the circumferential direction of the inner and outer filter media 1,2. However, a spiral (ribbon screw-shaped) partition 3 is arranged in the filtration space 4, and the cake rotating along the inner and outer filter media 1 and 2 interferes with the partition 3, thereby centering the axis. And move in the axial direction. By this movement, the cake is finally discharged from the cake discharge port 14 formed in the upper part of the filtration space 4 while being filtered and concentrated. In addition, although mentioned later, the back pressure plate 15 which suppresses discharge | emission of a cake is attached to the cake discharge port 14, and a cake is consolidated in the filtration space 4 by forcibly suppressing discharge | emission amount, The moisture content can be reduced.

  Although the filtration space 4 which concerns on embodiment has shown the cyclic | annular thing which has the same cross-sectional area from the top to the bottom, the lower part of the filtration space 4 has a large-capacity filtration chamber volume in order to ensure a processing amount. On the other hand, in order to improve the dewatering efficiency in the upper part of the filtration space 4, it is preferable to narrow the radius difference between the inner and outer filter media 1,2. Specifically, as shown in FIG. 5, the shape of the outer filter medium 2 remains the same, and the radial direction of the inner filter medium 1 continues from the liquid feed inlets 10 and 11 to the cake outlet 14 side. It is possible to propose a shape that increases in size (substantially conical shape) or a shape that expands in a staircase shape (multi-stage cylindrical shape) as shown in FIG. Further, as shown in FIG. 7, the radial direction of the outer filter medium 2 is continuously reduced from the liquid feed inlets 10, 11 side to the cake outlet 14 side while the shape of the inner filter medium 1 remains the same. It is also possible to propose a shape that is reduced, or a shape that is reduced stepwise as shown in FIG.

  As shown in FIGS. 1 and 2, the inner cleaning pipe 8 is provided along the inner peripheral surface of the inner filter medium 1, and a plurality of cleaning nozzles 8 </ b> A, 8 </ b> A,. The inner cleaning tube 8 is attached so as to face the peripheral surface. Similarly, the outer cleaning pipe 9 is provided along the outer peripheral surface of the outer filter medium 2, and the outer cleaning pipe 9A, 9A,... It is attached to the tube 9. Then, while rotating the inner filter medium 1 and the outer filter medium 2 around the axis, the cleaning water is jetted from the plurality of cleaning nozzles 8A, 8A,..., 9A, 9A,. 2 filtration surface is washed. The washing water sprayed at the time of washing is stored as washing wastewater on the bottom plate 7B of the casing 7 in the inner filter medium 1 and the bottom plate 7B between the casing 7 and the outer filter medium 2 together with the filtrate. The filtrate is discharged from the filtrate outlets 12 and 13.

  Here, the inner and outer filter media 1 and 2 are sprayed with a high-pressure cleaning liquid, but it is preferable that the cleaning is performed by spraying an alkaline chemical as the cleaning liquid. In addition, it is more preferable to install an ultrasonic transmitter on the filtration surfaces of the inner and outer filter media 1 and 2 to vibrate and clean the filter media themselves, since the cleaning power is improved.

  In addition, the installation positions of the inner and outer cleaning pipes 8 and 9 and the cleaning nozzles 8A and 9A are not limited to the above, and are installed in the filtration space 4, and a cleaning nozzle (not shown) is attached to the partition 3 and the like, so that the filtration space The cleaning liquid may be sprayed from within 4. Further, a plurality of inner and outer cleaning tubes 8 and 9 may be installed.

  As shown in FIG. 3, the cake discharge port 14 is formed in the part which projected the filtration space 4 in the upper plate 7A of the casing 7, From this, the dehydrated cake is discharged | emitted. A back pressure plate 15 is attached to the cake discharge port 14. The back pressure plate 15 generates discharge resistance, and by adjusting the amount of sludge to be discharged, the cake is further squeezed and the moisture content is reduced. Thus, the volume can be reduced.

<The filtration method according to the present invention>
The filtration method using the filtration apparatus according to the present invention will be described below.
First, the liquid to be processed is pumped to the liquid inlets 10 and 11, and the liquid to be processed is fed into the filtration space 4. The liquid to be treated sent into the filtration space 4 is subjected to two-side filtration by the inner filter medium 1 and the outer filter medium 2 while spirally rising along the partition 3. The inner filter medium 1 and the outer filter medium 2 are respectively rotated by first and second rotation driving means (not shown) such as a motor. At this time, if necessary, the inner filter medium 1 and the outer filter medium 2 are rotated in the same direction with a speed difference. The inner filter medium 1 and the outer filter medium 2 do not necessarily need to be rotated, and only one of them may be rotated.

  The liquid to be treated rises along the partition 3 due to the pumping pressure and rotational frictional force, but solid-liquid separation is performed in the lower part of the filtration space 4 between the inner filter medium 1 and the outer filter medium 2, In the upper part, dewatering is performed and finally a cake discharge port 14 is formed, from which the dehydrated cake is discharged.

  By rotating the inner filter medium 1 and the outer filter medium 2 and preventing the partition 3 from rotating, the scraper 16 scrapes off the cake accumulated on the respective filtration surfaces. At this time, as described above, the cleaning surfaces of the clogged inner filter medium 1 and outer filter medium 2 are cleaned by spraying cleaning water from the plurality of cleaning nozzles 8A, 8A,..., 9A, 9A,. The sprayed wash water is stored as wash wastewater on the bottom plate 7B of the casing 7 in the inner filter medium 1 and the bottom plate 7B between the casing 7 and the outer filter medium 2 together with the filtrate. It is discharged from the outlets 12 and 13.

  In the upper part of the filtration space 4, a cake having a high water content after the solid-liquid separation is raised rises. This cake is caused by rotational friction between the inner filter medium 1 and the outer filter medium 2 and discharged by the back pressure plate 15. Squeezing is promoted by the resistance, the moisture content is reduced, the volume is reduced, and the cake is discharged from the cake outlet 14.

It is a longitudinal cross-sectional view of the filtration apparatus which concerns on this invention. It is the II sectional drawing (transverse sectional view). FIG. It is the schematic for demonstrating the relationship between a partition and a scraper. It is a longitudinal cross-sectional view which shows the outline of the other Example of a filtration apparatus. It is a longitudinal cross-sectional view which shows the outline of the other Example of a filtration apparatus. It is a longitudinal cross-sectional view which shows the outline of the other Example of a filtration apparatus. It is a longitudinal cross-sectional view which shows the outline of the other Example of a filtration apparatus. It is a fragmentary top view for demonstrating the relationship between a scraper and an inner-outer filter medium. It is a fragmentary top view for demonstrating the relationship between the scraper of another Example, and an inner-outer filter medium (the 1). It is a fragmentary top view for demonstrating the relationship between the scraper of another Example, and an inner-outer filter medium (the 2). It is a partial top view for demonstrating the relationship between the scraper of another Example, and an inner-outer filter medium (the 3). It is the schematic for demonstrating the state which cut in the front-end | tip part of a scraper. It is the schematic for demonstrating the other fixing method of a scraper (the 1). It is the schematic for demonstrating the other fixing method of a scraper (the 2). It is the schematic for demonstrating the other fixing method of a scraper (the 3).

  DESCRIPTION OF SYMBOLS 1 ... Inner filter medium, 1A ... Upper plate, 2 ... Outer filter medium, 3 ... Partition, 4 ... Filtration space, 5 ... Inner cylinder rotating shaft, 7 ... Casing, 7A ... Upper plate, 7B ... Bottom plate, 8 ... Inner washing pipe, DESCRIPTION OF SYMBOLS 9 ... Outer washing pipe, 10 ... Liquid to be processed inlet, 11 ... Liquid inlet to be processed, 12 ... Filtrate outlet, 13 ... Filtrate outlet, 14 ... Cake outlet, 15 ... Back pressure plate, 16 ... Scraper 21 ... Scraper.

Claims (13)

A concentric arrangement of cylindrical or conical inner and outer filter media;
A spiral partition provided in a filtration space between the inner filter medium and the outer filter medium,
The axis is vertically oriented and the entire device is vertically oriented,
A configuration in which the liquid to be treated is fed upward from below the filtration space, the cake is discharged from the upper side in the filtration space, and the filtrate that has passed through the inner filter medium and the outer filter medium is discharged to the outside. A filtration device of
The inner filter medium and the outer filter medium rotate around an axis, the spiral partition is configured not to rotate, and the cake is raised along the partition by a frictional force with the rotating filter medium, and the filtration space Configured to be discharged from
Each of the inner filter material and said outer filtration scraping cake adhering to the material scraper, so as to be close to or in contact with the filtering surface, in the axial direction of the inner filter material and the outer filter media, and the inner peripheral edge of the partition of the spiral Provided in the filtration space along the outer periphery,
A filtering device characterized by that. The filtration device according to claim 1, wherein the scraper at least in the vicinity of the upper side of the filtration space is disposed so as to be positioned in a tangential direction of the inner filter medium and the outer filter medium. At least the scraper in the vicinity of the lower side of the filtration space is close to or in contact with the filtration surface, and the tip surface facing the cake conveyance direction is directed from the rear to the front in the cake conveyance direction, and the spiral of the partition The filtration device according to claim 1, wherein the filtration device is disposed at a swing angle with respect to a tangential direction of the inner filter medium and the outer filter medium, which is provided so as to be directed toward a center portion in a width direction of the belt-like band . The filtration device according to claim 4, wherein incisions along the width direction are formed at intervals in the vertical direction on a front end surface of a scraper facing the cake conveying direction . The scraper, the surface adjacent to or in contact with the filtering surface is the disposed so as to be located at the inner periphery and outer periphery respectively substantially the same on the circumference of the partition, any one of claims 1 to 4 The filtration device described. The filtration device according to any one of claims 1 to 5 , wherein the scraper is fixed on a lower side and an upper side of the filtration space. The filtration device according to any one of claims 1 to 5 , wherein the scraper is fixed by connecting either the lower side or the upper side of the filtration space and the peripheral edge of the partition. The filtration device according to any one of claims 1 to 5 , wherein the scraper is fixed by connecting peripheral edges of the partition. The filtration device according to any one of claims 1 to 5 , wherein the scraper is fixed only to either the lower side or the upper side of the filtration space. The filtration device according to any one of claims 1 to 9 , wherein at least an inner peripheral edge and an outer peripheral edge of the spiral partition on the inlet side of the liquid to be processed are close to or in contact with the inner filter medium and the outer filter medium, respectively. . The filtration device according to any one of claims 1 to 10 , wherein a rotation speed of the inner filter medium and a rotation speed of the outer filter medium are rotatable with a speed difference. The inner filter medium is provided with a first rotation drive means, the outer filter medium is provided with a second rotation drive means, and the first rotation drive means and the second rotation drive means are separate from the rotation drive means. The filtration device according to any one of claims 1 to 11 , wherein The filtration device according to any one of claims 1 to 12 , wherein the spiral partition is configured such that a pitch interval is shortened from the lower side toward the upper side .

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