WO2004087406A1

WO2004087406A1 - Rotary compression filtering machine and method for dewatering soft material being treated

Info

Publication number: WO2004087406A1
Application number: PCT/JP2003/003779
Authority: WO
Inventors: Takaharu Otsuka
Original assignee: Tomoe Engineering Co., Ltd.
Priority date: 2003-03-27
Filing date: 2003-03-27
Publication date: 2004-10-14
Also published as: AU2003227240A1

Abstract

A rotary compression filtering machine for compressing a cake efficiently while sustaining smooth discharge thereof in which the degree of dewatering is enhanced. A device effective for dewatering a treating liquid containing soft solid matters, and a method therefor. Two sheets of screen are disposed oppositely at a slight angle from parallelism and a cake is compressed during a process where the interval of the screens decreases. Alternatively, cross-sectional area of a filtration chamber is decreased gradually in the radial direction and the angle between a barrier wall plate and the rotational direction of the screen is set not larger than a specified value thus facilitating discharge of the cake. For a treating liquid containing soft solid matters, a rotary compression filtering machine having a plurality of supply openings is used and a first treating liquid containing a solid matter exhibiting higher liquid permeability than ordinary treating liquid is supplied from a first supply opening in order to form a layer of solid matter of high liquid permeability in the first treating liquid on the surface of the screen thus dewatering ordinary treating liquid being supplied from a second supply opening efficiently.

Description

Description Rotary compression filter and method for dehydrating soft processed material

The present invention relates to a machine for filtering and compressing a hydrated material (processed liquid) such as a raw material of a processed food or a semi-processed product thereof, or sludge, and performing a dehydration treatment. The present invention relates to a rotary compression filter that performs dehydration treatment by gradually applying pressure to a processed material as it progresses in a room, and in particular, a rotary compression filter suitable for dehydrating a hardly dewaterable treatment liquid containing a soft solid, and , Dehydration method. Background art

There are various types of devices for separating solids and liquids, such as centrifuges, centrifugal filters, filter presses, screw presses, rotary vacuum filters, and rotary compression filters. Of these, rotary compression filters with a structure as shown in FIGS. 11 to 16 are conventionally known.

FIG. 11 is a partially cutaway perspective view showing the structure of a conventional rotary compression filter 101, and FIG. 12 is an AA line of the rotary compression filter of FIG. FIG. As is clear from these figures, this rotary compression filter basically consists of a rotating shaft 102, an inner ring spacer 103, an outer ring spacer 104, and two donut. Screen 105, 105, a partition plate 106, and a back pressure device (not shown), an outer casing, a driving device, and the like.

More specifically, the rotation axis 102 is held almost horizontally, and When a driving force is supplied by a driving device (not shown), the motor rotates at a low speed of about 0.2 to 5.0 rotations in the direction of arrow B shown in FIG. The inner ring spacer 103 is fixed around a rotation axis, and rotates in the same direction according to the rotation axis.

The outer ring spacer 104 is arranged outside the inner ring spacer 103 and is held by an outer casing (not shown). The outer ring spacer 104 is positioned approximately 240 ° on the concentric circle of the rotating shaft 102 from the base end portion 104a. It is composed of a circular portion extending over about 300 ° and a straight line portion extending tangentially to the concentric circle up to the end portion 104b. Further, the outer ring spacer 104 is arranged such that, in the circular portion, the inner peripheral surface 104c thereof always faces the outer peripheral surface 103a of the inner ring spacer 1 at a constant interval. The thickness W1 of the outer race spacer 104 in the axial direction of the rotating shaft 102 matches the thickness W2 of the inner race spacer 103.

The two screens 105, 105 have inner peripheral portions 105a, 105a fixed on both sides of the inner ring spacer 103, respectively, and outer peripheral portions 105b, 105b have outer ring spacers. The spacers are arranged at positions and dimensions that are in contact with both side surfaces of the spacer 104. Therefore, when the rotating shaft 102 rotates, the screens 105, 105 rotate in the same direction according to the inner ring spacer 103. At this time, the outer peripheral edges 105b, 105b are It slides on both side surfaces of the outer ring spacer 104. Each screen 105, 105 has a number of small holes with a diameter of about 0.1 to 0.5 mm to ensure water permeability, and removes water from the processing solution as described later. The partition plate 106, which functions as a filter for the filter, is held substantially horizontally and in a direction orthogonal to the axial direction of the rotating shaft 102, and the thickness of the partition plate in the axial direction of the rotating shaft is Size W3 is equal to the thickness W1 of the outer race spacer 104 and the thickness W2 of the inner race spacer 103. The inner end 106a of the partition plate 106 is formed so as to conform to the curvature of the outer peripheral surface 103a of the inner ring spacer 1, make surface contact with the curvature, and slide.

The end (outside end 106 b) of the partition plate 106 opposite to the inside end 106 a is connected to the base end 104 a and the end 104 b of the outer ring spacer 104. The gaps are held at predetermined intervals. The space secured between the outer end portion 106b and the base end portion 104a of the outer ring spacer is provided as a processing solution supply port 108 for supplying the processing solution to be introduced into the apparatus. The space used between the outer end portion 106b and the end portion 104b of the outer race spacer 104 is used as a cake outlet 109.

The bottom surface 106c of the partition plate 106 matches the tangential direction of the outer peripheral surface 103a of the inner ring spacer 103, and the upper surface of the straight portion 104d of the outer ring spacer 104d. And extend in parallel. The rotary compression filter 101 is sealed by an outer casing, except for a processing liquid supply port 108, a cake outlet 109, and a liquid discharge port (not shown). A back pressure device having a movable valve 107 as shown in FIG. 16 is provided beside the cake outlet 109. The movable valve 107 of this back pressure device can freely adjust the opening area of the cake outlet 109 from the fully open state shown in (1) of FIG. 16 to the fully closed state shown in (2) of FIG. It has become.

Here, the operation method and operating principle of the conventional rotary compression filter 101 having the above structure are shown in FIG. 13 (a cross-sectional view of the rotary compression filter of FIG. 11 taken along the line CC). This will be briefly described with reference to FIG. 16 and FIG. First, at the start of operation, as shown in (2) of Fig. 16, the movable valve of the back pressure device 1107 is fully closed, and the filtration chamber 110 (the inner ring spacer 103 and the partition plate 10.6, and the outer ring spacer 10 The treatment liquid is introduced into the annular (C-shaped) space formed between the screens 4 and 4 in the space between the two screens 105 and 105). . At this time, since the movable valve 107 of the back pressure device is in the fully closed state as described above, the introduced processing liquid is not discharged to the outside from the cake outlet 109, and the inside of the filtration chamber 110 is not discharged. Will be stored.

The filtration chamber 110 is closed by two screens 105, 105 on opposite sides, but the screen 105 has a number of small holes to ensure water permeability as described above. In the process of storing the treatment liquid in the filtration chamber 110, the water in the treatment liquid passes through the small holes in the screen 105 and gradually drains out of the filtration chamber 110. Will be done. Then, the treatment liquid becomes a slurry by increasing the solid content concentration, and a part thereof adheres to the screen 105. The water discharged to the outside of the filtration chamber 110 flows down the gap between the inner wall of the outer casing and the screen 105, and is discharged to the outside of the apparatus from the liquid discharge port.

In this state, a driving device (not shown) is driven to supply a driving force to the rotating shaft 102, and the rotating shaft 102 is rotated 0.2 to 5.0 rotations / direction in the direction of arrow B shown in FIG. Rotate at a low speed of about a minute. Then, the inner ring spacer 103 fixed around the rotation axis 102 and the screens 105 fixed on both side surfaces of the inner ring spacer 103 rotate in the same direction.

When the screen 105 rotates, the processing liquid introduced into the filtration chamber 110 is processed by the frictional force generated between the rotating screen 105 and the slurry-like processing liquid attached thereto. From the supply port 108 to the cake outlet 109, the inside of the filtration chamber 110 is sequentially advanced. In this way, when the slurry-like processing solution proceeds inside the filtration chamber 110, it During the process, dehydration proceeds further, and the slurry-like treatment liquid gradually becomes a cake (a dehydrated cake). Then, the frictional force with the screen 105 also increases, and the dehydrated cake is transported further by the increased frictional force. Instead of being conveyed at the same speed as the screen 105, the preceding dewatered cake is compressed. As a result, the preceding dewatered cake is further dewatered.

In this way, the processing liquid introduced into the filtration chamber 110 undergoes dehydration as it approaches the cake outlet 109, and the filtration chamber 110 and the cake passage 1 1 2 (the filtration chamber 1 1 1 The dehydrated cake stays in the area from the end of 0 to the cake exit 109). Then, after a lapse of a predetermined time from the start of operation, when the movable valve 107 of the back pressure device is opened, the dewatered cake remaining near the cake outlet is continuously pushed out by the subsequent dewatered cake. However, it is discharged outside from the cake outlet 109 and shifts to steady operation.

In the steady operation, with the movable valve 107 of the back pressure device shown in Fig. 16 open, the treatment liquid supply port 108 through the filtration chamber 110 is opened as in the start operation. The treatment liquid is successively introduced into the furnace and the screen 105 is rotated at a predetermined speed so that the treatment liquid is continuously filtered and dehydrated, and the dehydrated cake is discharged from the cake outlet 109. I do. Even in such a steady operation, the filtration and dewatering operations from the introduction of the treatment liquid to the discharge of the dewatered cake are basically the same as those at the start operation described above. The dehydration degree can be adjusted to some extent by appropriately adjusting the rotation speed of the valve 05 and the opening of the movable valve 107 of the back pressure device.

As described above, this rotary compression filter 101 is an inner ring By simply rotating the circuit 103 and the screen 105 at a low speed, the processing liquid can be suitably separated into a liquid (moisture) and a solid (dehydrated cake). Because of low consumption and noise, and sealed by the outer casing, it is easy to manage hygiene when processing food and minimize odor when processing waste. There is an advantage that it can be suppressed. However, the rotary compression filter described above has some problems due to the internal pressure distribution. FIG. 15 is a diagram schematically showing the pressure in the filtration chamber. In FIG. 150, the screen 105 rotates in the direction of arrow B, so that the frictional force between the dehydrated cake and the screen 105 is determined by the rotational direction of the screen 105, that is, in FIG. It acts in the direction of the arrow F (F1-F5) shown. Of these, just below the rotation axis 102, the directions F1 and F2 in which the frictional force acts coincide with the traveling direction D4 of the dewatered cake, but the directions F1 and F2 As the position further advances from the position to the cake outlet 109 side, the frictional force acts in the direction of F3 to F5, that is, toward the bottom surface 106c of the partition plate 106.

For this reason, the dewatered cake located at F1 advances in the direction of F3 according to the frictional force with the screen 105, but at the position of F3, the frictional force is increased by the partition plate 106. The dewatered cake that has progressed from the position of F 1 because it is acting toward the bottom surface 106 c, is pressed against the bottom surface 106 c of the partition plate 106, and along the bottom surface 106 c. It proceeds in the direction of P 1 (the position where the outer peripheral portion of the screen 105 contacts the partition plate 106). While the dewatered cake located at F1 reaches the position of P1 along the bottom surface 106c of the partition plate 106 from the position of F1 to the position of P1, it is outside of F1 (outer ring spacer 10 The dewatered cake located on the 4 side) acts in the direction of F 3 and F 4 The so-called collision of forces occurs because it constantly moves toward the bottom surface 106 c of the partition plate 106 according to the frictional force that occurs, and therefore, near the bottom surface 106 c of the partition plate 106, especially, In the vicinity of P1, the dehydrated cake is compressed by the highest pressure in the filtration chamber 110. On the other hand, in the lower part of the cake passage 1 1 2, since there is no concentration of force as in P 1, compression is insufficient, a vertical difference in the degree of dehydration occurs, and the average dehydration degree does not increase There was a problem. That is, the cake moisture content at the position L shown in FIG. 14 tends to be higher than the cake moisture content at the position H.

In addition, pressure is concentrated near P1 in Fig. 15 and the direction of the frictional force by the screen 105 and the direction of the cake passage are largely inconsistent, and depending on the properties of the processed material, blockage may occur in the machine. There is also a problem that it is easy to do.

The cake conveyed from the filtration chamber 110 to the cake passage 112 is conveyed in the direction of the cake outlet 109 only by the pressure from the filtration chamber 110. Then, the internal pressure of the cake discharged from the cake outlet 109 outside the machine becomes equal to the atmospheric pressure. Therefore, the internal pressure of the cake located in the cake passage 1 12 gradually decreases as approaching the cake outlet 1 09 from the end of the filtration chamber 110.

Considering this point, consider the operation of the back pressure device as shown in FIG. The back pressure device is located adjacent to the cake outlet 109 as shown. Therefore, when the movable valve 107 is slightly closed, the internal pressure of the cake located near the cake outlet 109 slightly increases. However, in the cake located on the filtration chamber 110 side of the cake, the frictional force between the cake and the four surfaces constituting the cake passage 112 is integrated, so that the cake inside the cake passage 112 is The closer the cake is to the filtration chamber 110, the higher the internal pressure of the cake.

That is, as shown in FIG. 16, the back pressure device has a very simple configuration. Also, it functions as a means for increasing the internal pressure of the filtration chamber 110.

However, even if the movable valve 107 is slightly closed, the pressure near P1 shown in Fig. 15 may become abnormally high. It is difficult to freely control the internal pressure of the rotary compression filter 101 only by adjusting the opening degree of the filter.

Furthermore, when treating a treatment liquid containing a soft solid such as sewage sludge, a screen 105 having small holes of an appropriate size should be provided according to the properties of the soft solid contained. If the pores are too large, the floc will easily pass through the pores; if too small, the flock will block the pores and will be efficient at high pressures There is a problem that cannot be dehydrated. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems in the conventional rotary compression filter, and by adding a simple improvement to the conventional rotary compression filter, specifically, The cross-sectional area of the chamber is configured to gradually decrease, and by applying a compressive force to the cake in a direction different from that of the conventional rotary compression filter, the degree of dehydration of the cake is increased and the problem of clogging in the machine is avoided. Another object of the present invention is to provide an apparatus and a method capable of efficiently dehydrating a treatment liquid containing a soft solid material. Disclosure of the invention

The rotary compression filter according to the present invention includes two disk-shaped screens having water permeability that are opposed to each other at a predetermined interval, and two screens driven by a driving unit and rotated integrally with the screen. An inner ring movable spacer and an inner ring fixed spacer that is located between the two inner ring movable spacers and slides with them. A filter, an outer ring spacer in contact with most of the outer peripheral portion of the screen, and a filtration chamber surrounded by the outer ring spacer, and the filtration chamber includes an outer ring spacer from the inner ring movable spacer. The partition up to the spacer is divided by a partition plate that radially partitions the space, and one side of the partition plate is a starting end, the other end is a terminal, and a processing liquid supply port is formed near the starting end of the filtration chamber. A cake passage and cake outlet are formed adjacent to the terminal end, and the screen is continuously rotated from the processing liquid supply port to the cake outlet, and solid matter in the processed material is terminated at the filtration chamber end by the frictional force of the screen surface. The liquid is removed from the processing liquid by driving in the direction of the part to remove the liquid from the processing liquid, and the cake having the increased solid content concentration is discharged to the outside from the cake outlet. Opposite That screen and an angle of 1 to 1 0 °, are a feature that gradually filtration chamber cross-sectional area toward the filtration chamber end section is configured to decrease.

In addition, the rotary compression filter according to the present invention includes two disc-shaped screens having water permeability that face each other at a predetermined interval, and an inner ring that is driven by a driving unit and rotates integrally with the screen. A movable spacer; an outer ring spacer in contact with most of the outer peripheral portion of the screen; and a filtration chamber surrounded by the movable spacer, and the filtration chamber includes the inner ring movable spacer. The space from the circulator to the outer ring spacer is divided by a partition plate that radially partitions the space, and one side of the partition plate is a starting end, the other end is a terminal end, and a processing liquid supply port is provided near the starting end of the filtration chamber. A cake passage and a cake outlet are formed adjacent to the terminal end, and the screen is continuously rotated from the processing liquid supply port to the cake outlet. object By driving in the direction toward the end of the filtration chamber, the processed material is pressurized, the liquid is removed from the processing liquid, and the cake having an increased solid content is discharged from the cake outlet to the outside. More than two-thirds of In the region, the average of the collision angles formed by the cake contact surface of the partition plate and the rotation direction of the screen is 50 degrees or less, and the difference between the maximum value and the minimum value of the collision angle in the region is 15 It is characterized in that it is configured to be less than the temperature.

In this case, at the end of the filtration chamber, the sectional area of the filtration chamber in the traveling direction of the cake is gradually reduced over a rotation angle of 60 degrees or more, and the compression efficiency of the processed material at the end of the filtration chamber is reduced. It is preferable to configure so as to increase the value.

Further, at least one wall surface of the cake passage adjacent to the filtration chamber may have a movable member, and may have a means for further changing the cross-sectional area of the cake in the traveling direction.

Further, the rotary compression filter according to the present invention includes: two disc-shaped screens having water permeability that face each other at a predetermined interval; and an inner ring movable driven by driving means and rotated integrally with the screen. A spacer, an outer ring spacer in contact with most of the outer peripheral portion of the screen, and a filtration chamber surrounded by the outer ring spacer, and the filtration chamber includes the inner ring movable spacer. The space from the circulator to the outer ring spacer is divided by a partition plate that radially partitions the space, and one side of the partition plate is a starting end, the other end is a terminal end, and a processing liquid supply port is provided near the starting end of the filtration chamber. A cake passage and a cake outlet are formed adjacent to the terminal end, and the screen is continuously rotated from the processing liquid supply port to the cake outlet, and the frictional force on the screen surface causes the screen to rotate. Solids The processing liquid is removed from the processing liquid by driving it toward the end of the filtration chamber to remove the liquid from the processing liquid, and the cake having a high solid content concentration is discharged from the cake outlet to the outside. A second processing liquid supply port is provided at a position at a predetermined distance from the screen in the direction of rotation of the screen, and a normal processing liquid is supplied from the second processing liquid supply port. Arranging By supplying the first processing liquid containing a solid having better liquid permeability than the normal processing liquid from the first supply port, the layer of the solid having good liquid permeability in the first processing liquid is supplied. On the screen surface.

The method for dehydrating a treatment liquid containing a soft solid according to the present invention is a dehydration method performed using the rotary compression filter, wherein a normal treatment liquid is supplied into the apparatus from a second treatment liquid supply port. The first processing liquid is supplied from the first processing liquid supply port at 5 to 40% by weight of the supply amount of the second processing liquid, and the first processing liquid has 0.1 to 10% by weight. % Of fibrous substances. In addition, it is preferable that the main component of the fibrous substance is an opened cellulose fiber.

Further, it is preferable that the first processing liquid is obtained by adding 0.1 to 10% by weight of a fibrous substance to the second processing liquid. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a partially cutaway sectional view of a rotary compression filter 31 according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the rotary compression filter 31 of FIG. 1 taken along line AA.

FIG. 3 is a view for explaining the diameter of an inner ring spacer and a collision angle in a conventional general rotary compression filter.

FIG. 4 is a cross-sectional view of a rotary compression filter 51 according to a second embodiment of the present invention.

FIG. 5 shows the position and collision angle of the partition plate in the conventional rotary compression filter shown in FIG. 3 and the rotary compression filter according to the second embodiment of the present invention shown in FIG. 6 is a graph showing a relationship with the graph. FIG. 6 is a cross-sectional view of a rotary compression filter 51 according to a third embodiment of the present invention.

7 and 8 are diagrams showing another example of the configuration of the movable member 57 of the rotary compression filter 51 of FIG.

FIG. 9 is a sectional view of a rotary compression filter 71 according to a fourth embodiment of the present invention.

FIG. 10 is a schematic diagram when the outside of the filtration chamber 80 is viewed along the line AB in FIG.

FIG. 11 is a partially cutaway perspective view showing the basic structure of a conventional typical rotary compression filter 101.

FIG. 12 is a cross-sectional view of the rotary compression filter 101 of FIG. 11 taken along the line AA.

FIG. 13 is a cross-sectional view of the rotary compression filter 101 of FIG. 11 taken along the line CC.

FIG. 14 is an enlarged cross-sectional view near the cake outlet 109 of the rotary compression filter 101 of FIG.

FIG. 15 is a cross-sectional view for explaining the operation of the rotary compression filter 101 of FIG.

FIG. 16 is an explanatory view of the movable valve 107 of the back pressure device provided near the cake outlet 109 of the rotary compression filter 101 of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway sectional view of a rotary compression filter 31 according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. It should be noted that the rotary compression filter according to the present invention It is not limited.

The rotary compression filter 31 is composed of two disc-shaped screens 35a and 35b having water permeability, and inner ring spacers 33a and 33b rotating integrally with the rotating shafts 32a and 32b. It has a filtration chamber 40 surrounded by 33b and an outer ring spacer 34 in contact with most of the outer periphery of the screens 35a and 35b.

The screens 35a and 35b are formed of a smooth metal plate having a large number of small holes. The screens 35a and 35b need only be a porous material and have water permeability, and are generally used widely. Per-screen and wire mesh, or those formed of plastic, metal or ceramic sintered body, etc. can also be used.

The filtration chamber 40 is divided by a partition plate 36 that radially partitions the space from the rotating shafts 32 a and 32 b to the outer ring spacer 34, with one end of the partition plate 36 as a start end and the other end as an end. .

The rotary compression filter 31 has a processing liquid supply port 38 near the start end of the filtration chamber 40 and a cake passage 42 and a cake outlet adjacent to the end.

Has 39.

The screens 35a and 35b are configured to rotate continuously from the processing liquid supply port 38 to the cake outlet 39, and the solids in the processing liquid are generated by the frictional force of the inner surfaces of the screens 35a and 35b. Is conveyed toward the end of the filtration chamber 40. Then, pressurize the processing liquid according to the transport

However, it is configured to remove the liquid from the processing liquid and discharge the cake having an increased solid content to the outside from the cake outlet.

The rotary compression filter 31 is an improvement of the conventional rotary compression filter 101 shown in FIG. 11 and the like, and the basic operation principle is the same. Therefore, in the following description, only the improvements are described in detail to avoid duplication. The words that are described and used in the description of the present invention (eg, “filtration chamber”

“Cake passage”, “partition plate”, etc.) have the same meaning as the terms used in the background technology section, unless otherwise defined.

In this embodiment, as is clear from FIG. 2, the two screens 35a and 35b are not parallel but have a constant inclination, and the filtration chamber 40 is cut off. It is configured such that the area is gradually reduced. For this reason, a compressive force in a direction different from that of the conventional rotary compression filter can be applied to the cake. In other words, in the case of the conventional rotary compression filter, the cake conveyed by the rotation of the screen compresses the cake in front, and if the pressure of the cake in the front is higher than the conveying force of the cake, The above cake cannot be compressed, and the conveyed rear cake accumulates behind the front cake. On the other hand, in the present embodiment, in addition to the same compression mechanism as described above, a compression force acts in the thickness direction. After the cake layer with reduced fluidity accumulates in the filtration chamber 40, the two screens 35a and 35b transport the cake forward with both sides sandwiched between the cakes. Since the gap between 5a and 35b is small, forced conveyance and compression can be achieved compared to the conventional rotary compression filter. The screens 35a, 35b that are not parallel to each other are driven via different rotating shafts 32a, 32b connected to the inner ring movable spacers 33a, 33b. In FIGS. 1 and 2, a chain is used as the driving means. Alternatively, a chain is used from an external separate driving shaft or the bearing of the inner ring movable spacer 33a, 33b. It can be configured to be driven by gears from a common drive shaft penetrating the inside.

In the present embodiment, the inclination angles of the two screens 35a and 35b and the average gap are important factors. The inclination angle can be appropriately selected in the range of 1 to 10 degrees. If it is less than 1 degree, the compression effect is reduced, so the present invention is intended When the angle of inclination exceeds 10 degrees, many problems occur in the mechanical design, and the cross-sectional area of the filtration chamber 40 decreases too rapidly. The difference in compression ratio between the two becomes large, making it unsuitable for stable dehydration of processed materials. The inclination angles of the screens 35a and 35b are particularly preferably 3 to 6 degrees.

If the average gap between the two screens 35a and 35b is too large, the degree of reduction in the cross-sectional area of the filtration chamber 40 is undesirably small. As an example, the inclination angles of the screens 35a and 35b are 4 degrees, the average clearance is 50 mm, and the outer diameter of the inner ring spacers 33a and 33b and the inner diameter of the outer ring spacer 34 are set as follows. When the distances are 800 mm and 1200 mm, respectively, the maximum and minimum gaps of the screens 35 a and 35 b in the filtration chamber 40 are about 71 mm and 29 mm, They are 64 mm and 36 mm on the inner circumference. Therefore, the calculated value of the compression ratio during this period is 41% on the outer circumference, 56% on the inner circumference, and 48% in cross-sectional area. Next, a second embodiment of the present invention will be described. In the above-described first embodiment, the cake is compressed in the thickness direction by reducing the gap between the screens 35a and 35b, whereas in the second embodiment, the cake is compressed in the fourth direction. As shown in the figure, by keeping the angle of collision between the direction in which the cake is conveyed by the screen and the partition plate 56 below a certain value, the conveying force by the screen is made closer to the direction in which the cake travels, and the efficiency of compression in the conveying direction is improved. In addition, the reaction force of the partition plate 56 and the outer ring spacer 54 is effectively used by gradually reducing the cross section of the filtration chamber 60 in the traveling direction of the cake.

Prior to a detailed description of the second embodiment, the collision angle of a conventional general rotary compression filter will be described with reference to FIG. Inside radius of filtration chamber (inside If the radius of the wheel spacer is r and the outer radius of the filtration chamber (the inner radius of the outer wheel spacer) is R, r is in the range of 0.55 to 0.65 times R. It is common to set to In general, the cake contact surface of the partition plate extends linearly in the tangential direction of the inner ring spacer. In this case, the collision angle is 0 degree on the inner ring spacer side, but gradually increases as it approaches the outer ring spacer side.For example, when r = 0.5R, the collision angle becomes the inner ring spacer. The angle continuously increases from 0 degrees on the outer ring side to 60 degrees on the outer ring spacer side. That is, as the cake travels toward the end of the filtration chamber, displacement in the direction of travel of the cake and in the direction of frictional force due to the rotation of the screen increases, which hinders the discharge of the cake. Sometimes it was necessary to operate a low level of dewatering effect to cause blockage of the cake or to avoid blockage.

In Fig. 3, [A], [B], and [C1] are typical values of r, respectively, taking 0.4R, 0.5R, and 0.6R as examples. Indicates the collision angle when the inner ring spacer extends in the tangential direction of the inner ring spacer. The collision angle at the outer part of the filtration chamber is denoted as << 2, and the collision angle at the position where the screen located one-third from the inside of the donut-shaped filtration chamber contacts the partition plate is denoted as α1 in each figure. . The values of ο; 1 and 2 for [A], [Β], and [C 1], respectively, and their differences are as follows.

[A] (r = 0.6 R): «1 = 35.1,« 2 = 53.1, difference =

1 8.0 (degrees)

[B] (r = 0.5R): hi 1 = 41.4, α2 = 60.0, difference 18.6

[C 1] (r = 0.4 R): «1 = 48.2,« 2 = 66.4, difference = 18.2

In any case, α; 2 is greater than 1; the difference is more than 18 degrees . In other words, at the position of the collision angle of α1, a relatively large component acts in the traveling direction of the cake, whereas at the position of 2, a component larger than the component that contributes to the conveyance of the cake is directed to the partition plate. ing.

FIG. 5 is a graph showing the collision angles of [A], [Β], and [C 1]. The horizontal axis is the radial direction of the screen. In each case, the collision angle sharply increased from the collision angle of 0 degrees to the outer periphery of the screen.

C2 represented by a bold line in the figure represents the collision angle of the rotary compression filter 51 (see FIG. 4) according to the second embodiment of the present invention. The radius r of the inner ring spacer of C2 is set to 0.4R which is the same as C1. The collision angle of C 2 is almost the same as C 1 in the range of 0.4 to 0.5 R, but 1 of 1 becomes 48.2 degrees at 0.6 R, whereas C2 maintains 45 degrees throughout the rest. By giving a slight curvature to the cake contact surface of the partition plate, a low collision angle can be achieved on the outside, and more than half of the frictional force due to the rotation of the screen is reduced during the transport of the cake and the compression of the preceding cake. It can be used effectively.

The collision angle in the one-third area inside the partition plate is relatively small, and the partition plate comes into contact in this area because it is a fluid cake that has not yet been sufficiently dewatered. The angle does not need to be specified. However, as can be seen from Fig. 5, in the case of [B] and [C1], the collision angle exceeds 50 degrees in the area outside the partition plate, and the collision angle increases toward the outside Doing so will hinder the transport of the cake and the uniform compression of the preceding cake. Therefore, the weighted average of the collision angles in the two-thirds area (<< 1 to a2 area) outside the partition plate is preferably set to 50 degrees or less, and more preferably, over the entire area of this area. It should be 50 degrees or less. It is further preferable that the weighted average collision angle or the maximum collision angle be 45 degrees or less in this region. In addition, the variation of the collision angle in this region The angle of inclination is preferably within a maximum of 15 degrees, more preferably 10 degrees or less. It is most preferable to keep the collision angle in this region constant, or to make the collision angle smaller in the part or all of the outside in this region as it goes outside.

The collision angle can be reduced by increasing the radius of the inner ring spacer. For example, if r = 0.7 R, then 1 = 29.0, «2 = 45.6, and the difference = 16.6, and the cake conveyance is good. However, if the radius of the inner ring spacer is increased, the filtration area is reduced, and the processing capacity of the machine is also reduced, which is not economically favorable.

In contrast, with the specifications shown in Fig. 4 (r = 0.4R), the effective use area of the screen can be increased by about 64%, and the processing capacity is greatly improved.

The rotary compression filter 51 according to the second embodiment shown in FIG. 4 only reduces the collision angle to increase the cake transfer efficiency and efficiently compresses the preceding cake. Instead, the compression efficiency is increased by gradually reducing the cross-sectional area in the traveling direction of the cake at the end of the filtration chamber 60. In FIG. 4, the reduction in the cross-sectional area appears in the range of about 90 degrees in the rotation angle of the screen. The cake cannot be dehydrated simply by compression, but it requires time for the water in the cake to pass through the cake and pass through the screen. Therefore, it is not preferable to sharply decrease the cross-sectional area of the filtration chamber, for example, in a region where the rotation angle of the screen is less than 60 degrees. Conversely, by extending the inner ring spacer side of the partition plate, it is preferable to move the starting point of the reduction of the cross-sectional area of the filtration chamber to the rear, and to reduce the cross-sectional area of the filtration chamber more gradually.

The reduction rate (reduction rate) of the filtration chamber cross-sectional area is preferably 10% or more. No. If the aperture ratio is less than 10%, the compression effect intended by the present invention cannot be sufficiently increased. It is more preferable that the drawing ratio is 30% or more, and if only the dewatering effect is considered, a higher drawing ratio is preferable. Incidentally, the rotary compression filter shown in Fig. 6 has a reduction ratio of about 50%. Unfortunately, setting the squeezing rate to 50% does not simply reduce the water content of the cake by half. However, in the case of a filtration chamber with a constant cross-section, solid particles containing water in the cake are gradually compressed only in the direction of travel without changing their relative positions, whereas the cross-sectional area decreases. In the case of the embodiment, since the water-containing particles are forcibly moved in a direction other than the traveling direction, water in the water-containing particles and between the water-containing particles is gradually extruded. The drawing ratio can be arbitrarily set not only by changing the shape of the partition plate, but also by changing the shape of the cake outlet side end of the outer ring spacer. Further, by providing the movable member 57 at the cake outlet side end of the outer ring spacer, the drawing ratio can be arbitrarily changed during operation. FIG. 6, FIG. 7, and FIG. 8 are examples (third embodiment) of a rotary compression filter to which such a movable member 57 is added. The movable member 57 shown in these figures is apparently similar to the back pressure device 107 (FIG. 16) described in the related art in that the sectional area of the cake passage is changed. However, while the back pressure device 107 is provided adjacent to the cake outlet separated from the filtration chamber by a long cake passage, the movable member 57 of the present invention is adjacent to the filtration room, and the cake passage is provided. Are arranged to minimize their length. The movable member 57 shown in FIG. 6 has a rotation axis at a position adjacent to the outside of the outer ring spacer 54, a position where the cake passage is fully closed, a position where the cake passage is parallel, and It can be stopped at a position that makes it easier to discharge, or any position in between. At the start of operation By completely closing the movable member 57 (the position indicated by the dotted line in FIG. 6), it is possible to prevent the processing liquid from flowing out from the cake outlet. In the case of a processed material that is not likely to be clogged in the machine, it is possible to increase the drawing ratio to 80 to 90% while the movable member 57 is slightly opened from fully closed. In this case, the cake passage (the area outside the area between the two screens and up to the cake outlet) is extremely small, and the direction of the revolving motion of the screen in the filtration chamber 60 immediately before is determined by the direction of the cake in the cake passage. Since the subsequent cake can easily push out the cake in the cake passage because it is close to the conveyance direction.If the processed material is easily clogged in the machine, the movable member 57 can be positioned as shown by the solid line in Fig. 6. The cake can be easily discharged without giving excessive back pressure. Further, in the case of a processed product which is easily clogged, the cake can be directly discharged from the filtration chamber 60 by adjusting the movable member further below the position shown in FIG. In addition, a pressure sensor is attached to the partition plate 56 or the outer ring spacer 54 to detect the internal pressure of the machine and automatically control the opening of the movable member 57 to enable stable operation. Can be. As described above, the movable member 57 shown in the present embodiment is extremely useful in the rotary compression filter.

FIG. 7 shows an example in which a sliding movable member 57 is provided. FIG. 8 shows an example in which a partition wall plate is divided into two, and a partition plate on the cake contact surface side is a movable member 57. In both cases of Figs. 7 and 8, when the cake passage length is extremely short, and the displacement between the rotating direction of the adjacent screen and the moving direction of the cake is set small, and the drawing ratio is increased. However, the cake at the end of the filtration chamber is easily discharged by the pressure of the subsequent cake.

If there is a possibility that clogging may occur even when the movable member 57 shown in FIGS. 6, 7, and 8 is fully opened, a separate cake discharge device It is also possible to combine the positions. The inventor of the present invention has already disclosed an invention relating to a cake discharge mechanism of a rotary compression filter similar to the present invention in Japanese Patent Application No. 2000-1243. Therefore, by applying the cake discharging mechanism of Japanese Patent Application No. 2001-24043 to the present invention, even a clogged processed material can be suitably dewatered. Next, a description will be given of a fourth embodiment of the present invention, which is particularly suitable for dehydrating a soft solid substance. A typical example of a soft treated material is wastewater sludge. Wastewater sludge is fine organic matter dispersed in water, and it is difficult to filter it with a screen as it is. Usually, the sludge is made into a floc using a flocculant and dewatered. This floc is several millimeters to several centimeters in size and can be captured on a screen. However, since floc is a gel-like substance having a high water content, the eyes of the screen are easily closed. If the filtration pressure is increased unnecessarily to increase the dehydration efficiency, it may be pushed out of the screen. If the screen eyes are made smaller, clogging becomes more serious, and if the screen eyes are made larger, "eye leakage" that passes through the screen eyes is a troublesome substance that causes problems.

FIG. 9 shows a rotary compression filter 71 according to a fourth embodiment, which is based on the rotary compression filter shown in FIG. Although a processing liquid supply port 78b is provided, a plurality of processing liquid supply ports are of course based on the rotary compression filters 31 and 51 described as the first embodiment or the second embodiment. It is also conceivable to provide It is preferable that the first processing liquid supply port 78a and the second processing liquid supply port 78b are spaced from each other by a rotation angle of the screen of 20 to 90 degrees.

If the angle is less than 10 degrees, the first processing liquid and the second processing liquid are mixed, and the two-layer cake layer intended by the present invention cannot be formed. Not preferred. Even when the angle exceeds 90 degrees, the supply amount of the second processing solution is larger than the supply amount of the first processing solution, so that some of the processing solution flows backward, There is no major problem because it only merges with the processing solution at a certain position.

In this embodiment, the first processing liquid first contacts the screen 75 that has passed through the surface of the partition plate 76. Since there is no cake layer on the screen surface immediately after passing through the partition plate, the liquid components in the first processing solution pass through the screen quickly, but the solids in the processing solution pass through the screen. A cake layer with good liquid permeability is formed on the screen surface. If the second processing liquid is supplied before this cake layer is sufficiently formed, both processing liquids may be mixed, and the liquid permeability of the cake layer initially formed on the screen surface may be impaired. Therefore, it is necessary to provide a predetermined interval between the first processing liquid supply port and the second processing liquid supply port.

Here, a method of dewatering sludge using the rotary compression filter 71 will be described. The first processing liquid contains fibrous material, and is conveyed to the surface of the screen as the liquid component in the processing liquid flows toward the eyes of the screen, forming a thin layer on the screen surface. When the screen rotates and reaches the vicinity of the second processing liquid supply port 78b, the remaining fiber in the first processing liquid is supplied with the second processing liquid and formed on the surface of the screen. Gradually accumulates on the layer containing more fibrous material. The thin layer of fibrous material does not completely block the eyes of the screen, but has a gap that allows the liquid in the subsequent floc to pass, forming a thicker layer of cake.

When the screen is further rotated and the water in the processing liquid is discharged to the outside to some extent, the cake accumulated from both sides is filled up to the inner layer, but the outer layer, that is, the layer that contacts the screen surface, becomes a somewhat hard cake. The inner layer is a relatively soft cake, while fisting as a solid cake. Also holds. Therefore, the inner layer cake receives a low forward force due to the pressure from the subsequent liquid processing material, but the rotational force of the screen is transmitted to the inner layer through the cake layer that gradually softens from the screen surface. It does not contribute much to transporting the inner layer cake that has properties to the front.

Now, when the cake in this state is opposed to the harder cake that exists in front, the cake close to the liquid in the inner layer cannot proceed any further. On the other hand, the outer layer containing a large amount of fiber proceeds toward the cake in front due to the rotational force of the screen, but cannot move at the same speed as the screen because a hard cake already exists in the front. However, since the outer cake is pushed forward by the screen more than the inner cake is pushed by the subsequent soft cake, the fibrous cake layer is folded on the screen surface, It gradually penetrates into the inner layer. In this way, the cake layer containing a large amount of fibrous material, which initially formed a thin layer on the screen surface, gradually became thicker, and the function of guiding the moisture of the inner layer to the screen surface gradually extended to the inner layer. This will increase the dewatering efficiency.

FIG. 10 is a schematic diagram when the outside of the filtration chamber 80 is viewed along the line AB in FIG. A cake layer containing a large amount of the fiber component in the first processing liquid supplied from the first processing liquid supply port 78a is formed on the screen, and the cake layer is gradually formed at the end of the filtration chamber 80 by the rotation of the screen. In the process of being conveyed, it is schematically shown that it is folded on the screen surface and gradually becomes a thick layer.

In the present embodiment, the treatment liquid is supplied to the rotary compression filter 71 in two stages, and the liquid permeation is increased before the supply of the second treatment liquid that has been subjected to the ordinary coagulant treatment. Supply the first processing liquid with good quality. 1st liquid Permeability is obtained by adding 0.1 to 10% by weight of fibrous material. In this case, a part of the second processing solution may be used as the mother liquor, or the recovered filtrate may be reused, or both may be used in combination. In any case, the first processing liquid supplies about 5 to 40% of the second processing liquid. When the fibrous substance is added to the second processing solution to form the first processing solution, a relatively high rate of 15 to 40% is appropriate, and when the second processing solution is not used at all, A low rate of 5-20% is good. If the supply amount of the first processing liquid is less than 5%, it is difficult to form a layer containing the fibrous substance uniformly on the screen, which is not preferable.

The fibrous substance used in the present embodiment is a fibrous waste or surplus generated in industries such as papermaking, pulp, fiber, and wood, agriculture, and livestock, such as cotton litter, sawdust, rice hulls, and their crushed materials, Liquid waste such as waste liquid can be used. Among them, waste paper is circulating in large quantities on a regular basis, and waste paper subjected to open fiber treatment is particularly suitable for the present invention.

The chemical used for dewatering sludge with the rotary compression filter according to the present invention does not require any special agent. Metal salts such as iron chloride, aluminum chloride, iron sulfate, and aluminum sulfate, inorganic ash and zeolite used as a sedimentation aid, various acids and alkalis used for pH adjustment, and inorganic chemicals Nonionic, anionic, cationic, and amphoteric flocculants can be used as the polymeric flocculant, and these can be used in an appropriate combination. Industrial applicability

As described above, the rotary compression filter according to the present invention is capable of efficiently dewatering a processed material while suitably preventing clogging of the processed material in the device. Also, if the processing solution contains a lot of soft solids, the conventional rotary type With a compression filter, it was difficult to obtain a high dehydration rate because such soft materials passed through the eyes of the screen or clogged the eyes of the screen. According to the compression filtration machine, even if the treatment liquid contains a large amount of soft solids, it can be efficiently dewatered. Also, an appropriate part in the filtration chamber, for example, a partition plate or an outer ring spacer First, a pressure sensor is installed, and the pressure signal detected from this sensor is used as an input value to automatically control the supply amount of the processing liquid and the number of rotations of the screen. By automatically controlling the positions of the members, the dehydration rate of the cake can be maintained at a high level, and stable operation can be achieved.

Claims

The scope of the claims

1. Two permeable disc-shaped screens facing each other at a predetermined interval, two inner-ring movable spacers driven by driving means and rotating integrally with the screen, and 2 An inner ring fixed spacer located between two inner ring movable spacers and sliding with them, an outer ring spacer in contact with most of the outer peripheral portion of the screen, and a filter surrounded by the outer ring spacers And a room,

The filtration chamber is divided by a partition plate that radially partitions a space from the inner ring movable spacer to the outer ring spacer, and one end of the partition plate is a starting end, and the other end is a terminal end,

A processing liquid supply port is formed near the start end of the filtration chamber, and a cake passage and a cake outlet are formed adjacent to the end end,

The screen is continuously rotated from the processing liquid supply port to the cake outlet, and the solids in the processing object are driven toward the end of the filtration chamber by the frictional force of the screen surface to pressurize the processing object. The cake having a higher solid content concentration is discharged from the cake outlet to the outside, and one of the screens forms an angle of 1 to 10 degrees with the opposing screen,

A rotary compression filter characterized in that the cross-sectional area of the filtration chamber gradually decreases toward the end of the filtration chamber.

2. Two water-permeable disc-shaped screens facing each other at a predetermined interval; an inner ring movable spacer driven by driving means and rotated integrally with the screen; and an outer periphery of the screen An outer ring spacer in contact with most of the section, and a filtration chamber surrounded by them.

The filtration chamber is vacant from the inner ring movable spacer to the outer ring spacer. Are separated by a partition plate that radially separates them, with one side of the partition plate as a starting end and the other side as an end,

The screen is continuously rotated from the processing liquid supply port to the cake outlet direction, and the solids in the processed material are driven toward the end of the filtration chamber by the frictional force of the screen surface to pressurize the processed material, The cake with the increased solid content is discharged from the cake outlet to the outside, and the cake contact of the partition wall plate is made within two-thirds or more of the area outside the filtration chamber. The average of the collision angles that the surface makes with the rotation direction of the screen is 50 degrees or less, and the difference between the maximum value and the minimum value of the collision angles in the area is 15 degrees or less. A rotary compression filter characterized by the above-mentioned.

3. At the terminal end of the filtration chamber, the cross-sectional area of the filtration chamber in the traveling direction of the cake is gradually reduced over a rotation angle of 60 degrees or more. 3. The rotary compression filter according to claim 2, wherein the compression efficiency of the processed material is increased.

4. At least one wall surface of the cake passage adjacent to the filtration chamber has a movable member, and a means for further changing the cross-sectional area of the cake in the traveling direction of the cake is provided. Item 4. The rotary compression filter according to item 2 or 3.

5. Two permeable disc-shaped screens facing each other at a predetermined interval, an inner ring movable spacer driven by driving means and rotated integrally with the screen, and an outer periphery of the screen An outer ring spacer in contact with most of the section, and a filtration chamber surrounded by them.

The filtration chamber is divided by a partition plate that radially partitions a space from the inner ring movable spacer to the outer ring spacer, and one end of the partition plate is a starting end. And terminate on the other side,

The screen is continuously rotated from the processing liquid supply port to the cake outlet, and the solids in the processing object are driven toward the end of the filtration chamber by the frictional force of the screen surface to pressurize the processing object. Is removed from the cake outlet through the cake outlet, and the second processing liquid is supplied at a position at a predetermined distance from the processing liquid supply port in the rotation direction of the screen. Arrange the mouth,

A normal processing liquid is supplied from the second processing liquid supply port, and a first liquid containing a solid material having better liquid permeability than the normal processing liquid is supplied from a first supply port disposed adjacent to the partition plate. A rotary compression filter characterized in that a solid layer having good liquid permeability in the first processing liquid can be formed on the screen surface by supplying the first processing liquid.

6. A method for dehydrating a processing liquid containing a soft solid using the rotary compression filter according to claim 5, wherein a normal processing liquid is supplied into the apparatus from a second processing liquid supply port. The first processing liquid is supplied from the first processing liquid supply port in an amount of 5 to 40% by weight of the supply amount of the second processing liquid, and the first processing liquid is supplied in an amount of 0.1 to 10%. A method for dehydrating a treatment liquid containing a soft solid, wherein the treatment liquid contains a fibrous substance by weight.

7. The method for dewatering a treatment liquid containing a soft solid according to claim 6, wherein a main component of the fibrous substance is an opened cellulose fiber.

8. The first processing liquid according to claim 6 or 7, wherein the second processing liquid is obtained by adding 0.1 to 10% by weight of a fibrous substance to the second processing liquid. 13. A method for dehydrating a treatment liquid containing a soft solid according to item 10.