JP4820341B2 - 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. It is characterized by low power, low noise, low cost, etc., and is excellent when applied to a solid-liquid mixture with low solid content and low dehydration. In addition, it is widely used in the sewage sludge dehydration field. (For example, see 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 partition, which feeds the liquid to be treated from one end of the filtration space, discharges the cake from the other end of the filtration space, and passes through the inner and outer filter media. Is a filtration device configured to discharge the outside, and the inner filter medium and / or the outer filter medium rotate around the axis and the spiral partition is configured not to rotate (for example, Patent Document 3). 4).
JP 2001-212697 A JP 2001-113109 A JP 2006-346600 A JP 2007-160246 A

However, in the above invention, the apparatus itself can be reduced in size and the dewatering performance can be improved, but there is room for improvement with respect to cake discharge from the filtration space. That is, in the apparatus of the present invention, the cake formed in the filtration space is swirled and raised along a single spiral partition, and has been adopted as a structure that is led out and discharged in a tangential direction with respect to the swirling direction. There were the following problems.
(Ii) It is necessary to secure the cross-sectional dimension of the discharge path in accordance with the pitch of the spiral partition, and the length of the machine becomes long at a portion that does not contribute to dehydration.
(B) The discharged cake has a vertically long or horizontally long shape, and it is difficult to transfer the discharged cake by a conveyor.
(Ha) It is difficult to ensure sufficient strength of a single spiral partition when the lead is long.
Therefore, the main problem of the present invention is to solve these problems.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
A cylindrical or conical inner and outer filter media arranged concentrically;
A spiral partition provided in a filtration space between the inner filter medium and the outer filter medium and extending in a direction along the center of the inner filter medium while turning around the inner filter medium;
The inner filter medium and / or the outer filter medium is rotated around its center, and the spiral partition is configured not to rotate,
The liquid to be treated is fed from one end side of the filtration space, the filtrate that has passed through the inner filter medium and the outer filter medium is discharged to the outside, and the cake formed by this filtration is transferred along the partition A filtration device configured to be discharged to the other end side of the filtration space,
The partition is provided in a multi-row spiral shape,
A filtration device characterized by that.

(Function and effect)
Thus, when the partition is provided in a multi-row spiral shape, the pitch between the strips can be reduced in inverse proportion to the number of partitions without changing the lead of each strip. Therefore, the height of the discharge cake from the filtration space can be kept lower than in the case of 1 without significant changes in the device structure, and (a) the required height of the discharge path is reduced, and the overall height of the device is reduced. (B) The transportability of the discharged cake on the conveyor can be improved, (c) Even if the lead of the partition becomes long, the pitch between the lines can be suppressed, so the lines are connected. This brings about the advantage that the strength can be increased.

As described above, according to the present invention, the following advantages are brought about.
(A) The required size of the discharge path is reduced, and the captain can be suppressed.
(B) The transportability of the discharged cake on the conveyor is improved.
(C) Even if the lead of the partition becomes long, the pitch between the strips can be suppressed, so that the strength can be increased by connecting the strips.

  FIGS. 1-5 has shown the example of the filtration apparatus which concerns on this invention, and this filtration apparatus is arrange | positioned so that the center may follow the up-down direction, and the inner side filter medium 1 which makes a cylindrical shape, and the outer side, respectively. A filter medium 2, and a spiral partition 3 provided in a filtration space between the inner filter medium 1 and the outer filter medium 2 and extending so as to turn around the inner filter medium 1. Yes.

  As a filter medium used for the inner and outer filter media 1 and 2, a filter cloth can be used in addition to a screen of punching metal, wedge wire, wire mesh or the like. 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 punching metal may be arranged.

  As shown in FIG. 1 and FIG. 5, the partition 3 has a spiral shape (a spiral shape or a ribbon screw shape) extending so as to rise while turning around the inner filter material 1. A plurality of strips (two strips in the illustrated example) are provided in the cylindrical filtration space 4 formed between the outer filter medium 1 and the outer filter medium 2 with a uniform rotational angle difference in the circumferential direction. The inner peripheral edge and the outer peripheral edge of the partition 3 are close to or in contact with the filtration surfaces of the inner filter medium 1 and the outer filter medium 2, respectively. If the partition 3 is provided in a multi-row spiral shape, the height of the discharge cake can be suppressed, the required height of the discharge path can be reduced, and the overall height of the apparatus can be kept low. The advantage that it improves is brought about. In addition, it is preferable that the ratio of the pitch of the partition 3 to the radial interval between the inner filter medium 1 and the outer filter medium 2 (pitch / radial interval) be 1 to 5.

  Hereinafter, in more detail, the present apparatus example includes a horizontal main support base 40 and a horizontal sub-support base 41 supported by the main support base 40 that is provided above the main support base. Have. The outer filter medium 2 is rotatably supported by the main support base 40. Specifically, a cylindrical support portion 2X is added to the upper end of the outer filter medium 2, and an annular rotary plate 20 concentric with the outer filter medium 2 is formed on the upper surface of the support portion 2X (the upper surface is the annular rotation of the present invention). The inner peripheral edge of the first rotary pinion gear 21 is connected to the lower surface of the annular rotary plate 20 on the outer side in the radial direction, concentrically with the outer filter medium 2. The pinion gear 21 is supported by an annular rail 22 concentric with the outer filter medium 2 provided on the main support base 40. The teeth on the outer peripheral surface of the first annular pinion gear 21 are meshed with the pinion gear G1 of the drive shaft of the first motor M1 mounted on the main support base 40.

  The lower end portion of the inner filter medium 1 is connected and integrated with the lower end portion of the outer filter medium 2 via an annular plate 6 that closes the lower opening between the inner and outer filter mediums 1 and 2 (filtration space) below the lower end of the partition 3. Has been. Therefore, by driving the first motor M1, not only the outer filter medium 2, but also the inner filter medium 1 connected thereto is integrally driven to rotate. Further, above the lower connection position (annular plate 6) of the inner and outer filter media 1, 2, the two filter media 1, 2 are not connected, and the upper portion between the two filter media 1, 2 (filter space 4) is annular. The partition 3 protrudes above the upper end of the outer filter medium 2 through the annular opening. An annular support portion 3X is added to the upper end of the partition 3, and the upper end of the support portion 3X is suspended and supported on the upper portion of the apparatus by being connected and fixed to the sub-support base 41, and the lower end of the partition 3 is filtered. It is located near the lower end of the space 4. The inner filter medium 1 also projects upward from the upper end of the outer filter medium 2, and the upper end of the inner filter medium 1 is pivotally supported by the sub-support base 41. By integrating the structure, supporting the cantilever, and sharing the drive in this way, the maintenance is excellent, the number of parts is small, and the assembly is easy.

  A lower casing 42 is suspended and supported on the lower side of the main support 40 so as to surround and surround the outer filter media 1 and 2 with a gap corresponding to the filtrate discharge space 16. The lower casing 42 only forms the filtrate discharge space 16, and a large load is not applied.

  A filtrate outlet 13 is provided at the bottom of the lower casing 42. In addition, the liquid supply pipe 10 for the liquid to be treated passes from the outside of the lower casing 42 through the bottom of the lower casing 42 to the lower ends of the inner and outer filter media 1 and 2, at the center of the inner and outer filter media 1 and 2. After extending along the radial direction, the tip extends through the inner filter medium 1 and opens into the filtration space 4 above the annular plate 6. A swivel joint 45 is interposed in the feed pipe 10 outside the lower casing 42 and can be rotated with the rotation of the inner and outer filter media 1 and 2 while maintaining the communication state inside the pipe. ing. The liquid to be treated is fed by pressure by a pump (not shown) through the feed pipe 10. In addition, although the inlet conduit 10 passes through the inner filter medium 1, the inner filter medium 1 is open downward, so that the inner filter medium 1 and the outer filter medium 2 communicate with the common filtrate discharge space 16. ing. Therefore, the filtrate discharge path is compact and simple.

  On the upper side of the filtration space 4 (equal to the upper side of the outer filter medium 2), there is provided a cylindrical discharge space 4X formed by continuously extending the filtration space 4 as it is. The upper part of the discharge space 4X is surrounded by the bottom surface of the support part 3X of the partition 3, and the inner periphery is surrounded by the outer periphery of the inner filter medium 1. Each partition 3 extends to the upper end of the discharge space 4X, and a terminal wall 3E is erected on the upper surface of the lower end portion of the portion from the lower end to the upper end of each extended portion. The outer peripheral surface up to the upper end is covered with a peripheral wall 3R that covers the same height range as the end wall 3E, and an opening between the peripheral walls 3R serves as a discharge port 24 that opens to the outer peripheral surface (side surface) of the discharge space 4X. The number of the partitions 3 is formed. The end wall 3 </ b> E has a function of receiving the cake rising along the partition 3 and pushing it out to the discharge port 24.

  The outer periphery of the discharge space 4X is concentrically surrounded by a cylindrical opening adjusting body 26. An opening 26 </ b> X is formed in the opening adjusting body 26 at a position overlapping the discharge port 24, and an annular top plate 26 </ b> P is projected so as to cover the upper part of the annular rotating plate 20. The opening adjusting body 26 is rotatable in the circumferential direction of the discharge space 4 </ b> X, and is connected to the second annular pinion gear 27 concentrically at the upper end surface thereof, and the teeth on the outer peripheral surface of the second annular pinion gear 27. Is meshed with the pinion gear G2 of the drive shaft of the second motor M2 mounted on the sub-support base 41. By moving the opening adjusting body 26 by the drive control of the second motor, the area of the portion overlapping the non-opening portion other than the opening portion 26X and the discharge port 24 changes, and the opening area (opening portion) of the discharge port 24 changes. 26X) is adjusted.

  In order to detect the position of the aperture adjuster 26, a plurality of non-contact sensors 30 such as proximity switches are provided at intervals in the moving direction of the aperture adjuster 26. In the illustrated embodiment, one or a plurality of detection units (detection plates) 31 are provided at appropriate positions on the upper side of the annular top plate 26P of the aperture adjuster 26 so as to be position-adjustable, and the detector 31 associated with the movement of the aperture adjuster 26 The non-contact sensor 30 is provided on the movement trajectory, and based on the correspondence between the position detected by the non-contact sensor 30 and the position of the opening adjuster 26, the position of the opening adjuster 26, that is, the release position. The opening area of the outlet 24 can be detected. By controlling the driving of the second motor M2 based on this detection result, the back pressure can be controlled based on the opening area of the discharge port 24.

  The annular rotating plate 20 described above has an upper surface located between the lower end of the discharge port 24 and the upper end of the outer filter medium 2 and is provided so as to surround the discharge space 4X in plan view. A discharge guide plate 25 is erected on the upper side of the annular rotary plate 20 so as to cross from the inner peripheral edge to the outer peripheral edge of the annular rotary plate 20. The lower end of the discharge guide plate 25 is slightly separated from the upper surface of the annular rotary plate 20. The inner end of the discharge guide plate 25 (the end located on the inner peripheral side of the annular rotating plate 20) is in contact with the outer side edge of the termination wall 3E in any one discharge port 24, and the outer end. Is connected to the main support 40 so as to protrude outward from the outer peripheral edge of the annular rotating plate 20. The discharge guide plate 25 crosses the annular rotating plate 20 obliquely with respect to the radial direction so as to be positioned on the rear side in the rotation direction of the annular rotating plate 20 as it goes to the outer end.

  Further, at a position located between the discharge ports 24 in the rotation direction on the upper side of the annular rotating plate 20, so as to cross from the inner periphery of the annular rotating plate 20 to an intermediate position (for example, the center) between the inner periphery and the outer periphery. An outside guide plate 29 is erected. The lower end of the outer guide plate 29 is slightly separated from the upper surface of the annular rotating plate 20, and the inner end (the end located on the inner peripheral side of the annular rotating plate 20) is the outer peripheral surface of the opening adjusting body 26. It is connected to. Further, the outer guide plate 29 crosses the annular rotary plate 20 obliquely with respect to the radial direction so as to be positioned on the rear side in the rotational direction of the annular rotary plate 20 toward the outer end.

  The outer periphery of the annular rotary plate 20 and the annular top plate 26P is surrounded by a cylindrical upper casing 43. In the upper casing 43, a range from a circumferential position corresponding to the inner end of the discharge guide body 25 to a circumferential position corresponding to the outer end is opened as a discharge chute 44. In the illustrated embodiment, the upper casing 43 has an upper end connected to the sub-support base 41 and a lower end connected to the main support base 40, and the sub-support base 41 is supported by the sub-support base 41 via the upper casing 43. It has become.

  On the other hand, in the illustrated embodiment, an inner cleaning pipe 8 and an outer cleaning pipe 9 are provided for cleaning the inner and outer filter media 1 and 2, respectively. 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. Water or alkaline chemicals can be used as the cleaning liquid.

  In the thus configured filtration device, the filtration operation can be performed as follows. That is, the first motor M1 is actuated to integrally rotate the inner filter medium 1, the outer filter medium 2 and the annular rotating plate 20 in the same direction as the upward turning direction of the partition 3, and the liquid feed pipe 10 to be treated. Then, the liquid to be treated is pumped 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. More specifically, the liquid to be treated fed from the liquid feed pipe 10 to be treated has a low solid content and a fluidity. In the lower part of the filtration space 4, the inner filter medium 1 and the outer filter medium are provided. Filtration concentration occurs through the openings in 2. As the concentration proceeds, the fluidity is lost and a cake is formed. The cake moves in the circumferential direction of the filtration space 4 by friction with the rotating inner and outer filter media 1 and 2. At this time, since the spiral partition 3 is arranged in the filtration space 4, the cake rotating along the inner and outer filter media 1 and 2 interferes with the partition 3, When the feeding pressure is applied from below, it turns up around the axis. By this movement, solid-liquid separation is performed at the lower part of the filtration space 4 to form a cake. The cake is pressed and dehydrated at the upper part of the filtration space 4 and then pushed up from the upper part of the filtration space 4 to the discharge space 4X.

  On the other hand, the filtrate discharged into the inner filter medium 1 and out of the outer filter medium 2 by filtration is stored at the bottom of the lower casing 42 and discharged from the filtrate discharge port 13.

  The cake pushed up to the discharge space 4 </ b> X along each partition 3 is discharged onto the annular rotating plate 20 through each discharge port 24. At this time, on the rear side in the rotation direction of each discharge port 24, the cake located from the inner peripheral edge to the intermediate position on the annular rotary plate 20 is pushed in advance to the outer peripheral edge side by the outer guide plate 29. A cake discharge space is secured at the discharge position. The cake placed on the annular rotating plate 20 is pushed out from the annular rotating plate 20 to the outer discharge chute 44 by the common discharge guide 25 in the process of being rotated and transferred with the rotation of the annular rotating plate 20, and is outside the machine. To the next processing step via a conveyor.

  On the other hand, at the time of cleaning, the inner filter medium 1 and the outer filter medium 2 are rotated around the axis, and the cleaning water is jetted from a plurality of cleaning nozzles 8A, 8A,..., 9A, 9A,. The filtered surfaces of the inner filter medium 1 and the outer filter medium 2 are washed. The washing water sprayed at the time of washing is stored as washing waste water together with the filtrate in the lower part of the lower casing 42 and is discharged from the filtrate discharge port 13.

<Others>
(A) In the above example, the inner peripheral edge and the outer peripheral edge of the partition 3 are close to or in contact with the filtration surfaces of the inner filter medium 1 and the outer filter medium 2, respectively. 4 is strongly exerted near the liquid inlets 10 and 11 to be processed, so that the inner and outer edges of the partition 3 are at least the inner and outer filter media 1 near the inlets 10 and 11 of the liquid to be processed. Any structure may be used as long as it is close to or in contact with each other.

(B) The partition 3 may have a uniform spiral pitch in the entire filtration space 4, but may be configured to become narrower as it goes upward as shown in FIG. Conversely, the pitch of the spiral partition 3 may be increased as it goes from the bottom plate 7B side of the casing 7 to the upper plate 7A side.

(C) 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 is a large-capacity filter in order to ensure a processing amount. In order to increase the chamber volume and to improve the dewatering efficiency in the upper part of the filtration space 4, it is also a preferable form to narrow the radial difference between the inner and outer filter media 1,2.
Specifically, as shown in FIG. 6, the shape of the outer filter medium 2 remains the same, and the radial direction of the inner filter medium 1 is continuously expanded from the liquid feed side to the cake discharge side. It is possible to propose a shape that follows a shape (substantially conical shape) or a shape that expands stepwise as shown in FIG. 7 (a multistage cylindrical shape). Moreover, as shown in FIG. 8, the shape of the inner filter medium 1 remains the same, and the radial direction of the outer filter medium 2 is continuously reduced from the liquid feed side to the cake discharge side, Alternatively, it is possible to propose a shape that reduces in a stepped manner as shown in FIG.

(D) 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 radius difference is generated, so that shear force is generated in the cake. Thus, dewatering efficiency is improved. For example, this shearing force is more effective for a liquid to be treated containing raw sludge having a high fiber content or mixed raw sludge. Depending on the cake properties, when a shearing force is applied, the cake may be fluidized, and conversely, the dewatering property may be impaired. In such a case, it is preferable to rotate the cake at a constant peripheral speed difference. In addition, a cake that has a dehydrating effect due to a shearing force and whose cake properties hardly change throughout the year can be rotated with a constant peripheral speed difference.

(E) When the inner filter medium and the outer filter medium are driven independently as in the prior art, it is possible to further improve the dewatering efficiency by rotating the inner filter medium 1 and the outer filter medium 2 with a speed difference. It is. Since this effect depends on the properties of the target cake, it is desirable to set the speed difference between the inside and outside according to the properties of the cake when operating in the optimum state. In particular, when the relative speed between the inner filter medium 1 and the outer filter medium 2 is large, the cake in the vicinity of the rapidly rotating filter surface (for example, the filter surface of the inner filter medium 1) is filtered on the other filter surface (for example, the filter 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. 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.

(F) In the above example, the axes of the filter media 1 and 2 are vertically oriented (along the vertical direction), the entire apparatus is vertically oriented, and the liquid to be treated is fed in a pressurized state from below to above. However, the axial centers of the filter media 1 and 2 may be laterally (along the horizontal direction), and the entire apparatus may be disposed laterally. In the case of the horizontal orientation, the inside of the apparatus may be moved only by the frictional force generated by the rotation of the inner filter medium 1 and the outer filter medium 2 without pumping the liquid to be treated. However, 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. On the other hand, if the axial center is vertically oriented and the entire apparatus is vertically oriented, and the liquid to be treated is sent in a pressurized state from the bottom to the top, the filtrate is drawn using gravity. It is possible to prevent leaching to the upper 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.

It is a longitudinal cross-sectional view of a filtration apparatus. It is the A section enlarged view of FIG. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is a perspective view of a partition. It is a longitudinal cross-sectional view which shows the outline of another filtration apparatus. It is a longitudinal cross-sectional view which shows the outline of another filtration apparatus. It is a longitudinal cross-sectional view which shows the outline of another filtration apparatus. It is a longitudinal cross-sectional view which shows the outline of another filtration apparatus.

  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, 7C ... Inclined surface, 8 ... inner cleaning pipe, 9 ... outer cleaning pipe, 10 ... liquid to be treated, 13 ... filtrate outlet, 14 ... filtration space outlet, 16 ... filtrate discharge space, 20 ... annular rotating plate, 24 ... release Outlet, 25 ... Discharge guide, 26 ... Opening adjuster, 29 ... Outer guide, 40 ... Main support, 41 ... Sub support, 42 ... Lower casing, 43 ... Upper casing, 44 ... Discharge chute, 45 ... Swivel fitting.

Claims (1)

A cylindrical or conical inner and outer filter media arranged concentrically;
A spiral partition provided in a filtration space between the inner filter medium and the outer filter medium and extending in a direction along the center of the inner filter medium while turning around the inner filter medium;
The inner filter medium and / or the outer filter medium is rotated around its center, and the spiral partition is configured not to rotate,
The liquid to be treated is fed from one end side of the filtration space, the filtrate that has passed through the inner filter medium and the outer filter medium is discharged to the outside, and the cake formed by this filtration is transferred along the partition A filtration device configured to be discharged to the other end side of the filtration space,
The partition is provided in a multi-row spiral shape,
A filtration device characterized by that.

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