JP2004074110A - Filtration apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filtration apparatus which can be back washed in the highest efficiency by enabling a filtrate present in an upper chamber first to be effectively utilized for back washing the apparatus when a back washing step starts and having constitution such that only the upper chamber can be filled with water. <P>SOLUTION: The filtration apparatus is constituted by dividing a filtration column by a partition plate into the upper chamber as a filtrate chamber and a lower chamber as an original water chamber and hanging a filter element on the partition plate so that the upper end part of the filter element penetrates the partition plate and extends downward from the partition plate. An opening is arranged at the projecting part formed by allowing the upper end part of the filter element to project upward from the partition plate and an outer cylinder is arranged for covering the projecting part while leaving a space between the projecting part and the outer cylinder to form a flow passage reaching the opening. An opening is arranged on the outer cylinder at the position lower than that of the opening of the projecting part for allowing the flow passage to communicate with the outside of the outer cylinder and a small hole is also arranged on the outer cylinder at the position higher than that of the opening of the projecting part for allowing the inside of the outer cylinder to always communicate with the outside. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a filtration device having a plurality of filter elements suspended in a filtration tower, and particularly to a filtration device capable of obtaining excellent backwashing properties.
[0002]
[Prior art]
Conventionally, for example, as shown in FIG. 7, the inside of a filtration tower 101 is partitioned by a partition plate 102 into an upper chamber 103 as a filtered water chamber and a lower chamber 104 as a raw water chamber, and is directed downward from the partition plate 102. A filtering device 106 of a type in which an extending filter element 105 is suspended is known, and is used in various industrial fields. In the filtration device 106, when performing a filtration process, raw water 107 (for example, condensed water in a power plant) as the water to be treated is introduced into the lower chamber 104 from below and impurities (for example, , The filtered water that has flowed into the filter element 105 while trapping fine particles made of iron oxide, etc., is guided to the upper chamber 103 and flows out as filtered water 108 from the upper chamber 103. At the time of backwashing, backwashing water 109 is poured into the filtration tower 101 from the lower chamber 104 side, and the backwashing water is spread above the partition plate 102 (in the upper chamber 103). The water in the chamber 104 is discharged, and the water in the upper chamber 103 flows in a direction opposite to that of the filtration, so that the filter element 105 for removing impurities trapped on the outer surface of the filter element 105 is backwashed. When the backwash water is introduced directly into the upper chamber 103, the backwash water falls to the lower chamber 104 side at the time of introduction, and effective backwash cannot be performed. Of water. At the time of draining, the inside of the upper chamber 103 is opened to the atmosphere. At the time of backwashing, not only the inside of the upper chamber 103 is opened to the atmosphere, but also the backwash air 111 (pressurized air) is supplied into the upper chamber 103. The backwashing operation can be performed more smoothly. In such a backwashing operation, the first operation is most effective for removing impurities, but is usually repeated in order to obtain a sufficient backwashing effect.
[0003]
However, in the above-described backwashing, when the filter element 105 is backwashed, since water also exists in the lower chamber 104, the flow velocity of the water flowing back through the filter element 105 is reduced by a drain pipe 112 (drain pipe). Governed by the flow velocity of the water passing through it. As the drain pipe 112, a pipe having a large diameter is used, and a drain valve which can be quickly opened is also used. However, there is a limit to an increase in the drain flow rate, and the flow rate of the backwash water is also limited. Limits arise. Since it is not possible to increase the flow rate of the backwash water, there is a limit to the improvement of the backwash performance. In addition, in the above-described backwashing, since the water in the lower chamber 104 which does not contribute to the backwashing is also discharged as the backwashing water, a large amount of water is consumed for the backwashing and the amount of the backwash waste liquid increases. Would. As the backwashing is repeated, the consumption amount and the waste liquid amount increase.
[0004]
To solve such a problem, as shown in FIG. 8, the upper end 122 of the filter element 121 is protruded above the partition plate 123, and an opening is provided in the top surface of the protruded upper end 122. There has been proposed a structure in which the protruding portion is covered by a gap with respect to 122 and an outer cylinder 124 is opened downward at the lower end (Japanese Utility Model Publication No. 56-35224). In this structure, after draining water from the inside of the filtration tower, it is possible to fill the partition plate 123 with water up to the level of the opening of the upper end 122, and introduce compressed air into the upper chamber to filter the stretched water. The filter element 121 is quickly back-flowed into the lower chamber through the element 121 so that the filter element 121 can be back-washed.
[0005]
In addition, as shown in FIG. 9, a check valve 125 is further provided on the upper part of the outer cylinder 124 for the above structure, the check valve 125 is opened when water is filled, and the check valve 125 is closed when compressed air is introduced. There has also been proposed a structure in which the stretched water is passed through the filter element 121 through a predetermined flow path so that the filter element 121 can be backwashed (Japanese Utility Model Publication No. 57-2021).
[0006]
[Problems to be solved by the invention]
However, the structures proposed in JP-B-56-35224 and JP-B-57-2021 still have the following problems. That is, when the backwashing step is started after the filtration step is completed, the upper chamber is opened to the atmosphere and the drain pipe is opened to discharge the water in the filtration tower from the lower chamber. In the structure shown in Japanese Utility Model Publication No. 56-35224, since the siphon phenomenon acts on the water existing between the upper end 122 of the filter element 121 and the outer cylinder 124, all the water existing in the upper chamber is also discharged. Would. At the time of this discharge, as described above, the discharge flow rate from the drain pipe is governed by the law. Therefore, it is difficult to increase the back flow velocity of water to the filter element 121, and it is not possible to perform effective backwashing. Thereafter, when only the upper chamber is filled with water, the backflow can be rapidly performed as described above, and effective backwashing can be performed. In other words, the filtered water initially present in the upper chamber is almost wasted without being effectively used for backwashing. As described above, in the backwashing step, since the first backflow is the one that can exert the most effective cleaning, the above-described structure that wastefully discharges the filtered water that was initially present in the upper chamber from this aspect. It is difficult to say that a sufficiently efficient backwash has been achieved.
[0007]
Also, in the structure of Japanese Utility Model Publication No. 57-2021 shown in FIG. 9, when the drain pipe is opened to discharge the water in the filtration tower from the lower chamber, the reverse pipe provided on the upper part of the outer cylinder 124 is used. Since the stop valve 125 is configured to be closed, the siphon phenomenon also acts at the time of the first drainage, and all the filtered water that initially exists in the upper chamber is discharged. Therefore, the same problem as described above remains.
[0008]
Therefore, an object of the present invention is to focus on the above-mentioned problems still remaining in the structures proposed in Japanese Utility Model Publication No. 56-35224 and Japanese Utility Model Publication No. 57-2021, and start the backwashing process. In doing so, the filtered water that was initially present in the upper chamber was effectively used for backwashing, and the most efficient backwashing was achieved in conjunction with the structure that allowed water to fill only the upper chamber. It is to provide a filtration device.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a filtration device according to the present invention is configured such that the inside of a filtration tower is partitioned by a partition plate into an upper chamber as a filtered water chamber and a lower chamber as a raw water chamber, and the partition plate has an upper end portion. In a filtering device in which a filter element extending downward from a partition plate while penetrating the partition plate is suspended, an upper end portion of the filter element is protruded above the partition plate to provide an opening in the protruding portion. In contrast, an outer cylinder that covers the protruding portion with a gap and forms a flow path to the opening between the protruding portion and the outer cylinder is provided, and the outer cylinder has a position below the opening of the protruding portion. An opening for communicating the flow path with the outside of the outer cylinder is provided, and a small hole for always communicating the inside and the outside of the outer cylinder is provided at a position above the opening of the protruding portion. That is, the outer cylinder of the present invention basically differs from any of the structures of Japanese Utility Model Publication No. 56-35224 and Japanese Utility Model Publication No. 57-2021 in that it has a small hole that is always open.
[0010]
In this filtration device, the outer cylinder may be fixed to the upper end of the filter element, and may be configured to be integrally handled with the filter element, or may be fixed to a partition plate separately from the filter element. it can. Further, the outer cylinder may be provided for each filter element, or may be configured as a common outer cylinder for a plurality of filter elements.
[0011]
In such a filtration device according to the present invention, when entering the backwashing step after the end of the filtration step, the upper chamber is opened to the atmosphere and drained from the lower chamber, but with the drainage from the lower chamber, The filtered water that was present in the upper chamber is discharged to the lower chamber side up to the water level of the opening of the upper projecting part of the filter element, but since the siphon is cut off by the small hole, it is not discharged any more and the partition It remains in the upper room on the board. This residual water can be quickly returned by the pressurized air through the filter element to the lower chamber from which the water is drained. That is, the filtered water that was initially present in the upper chamber can be left in the upper chamber as backwashing water, and can be used for effective backwashing by rapid backflow. Water can be used as the most effective first backwash water. Thereafter, similar to the structure proposed in Japanese Utility Model Publication No. 56-35224 or Japanese Utility Model Publication No. 57-2021, the necessary number of times, water filling in the upper chamber, and backwashing may be repeated. As described above, in the filtration device according to the present invention, the first backwashing operation can be effectively performed while keeping the advantage of the water filling configuration only in the upper chamber, and the most efficient operation as the whole backwashing process is performed. Can be performed.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a filtration device 1 according to one embodiment of the present invention. The filtration device 1 is provided horizontally in a filtration tower 2 and the filtration tower 2, and the inside of the filtration tower 2 is used as a filtration water chamber. It has a partition plate 5 for partitioning into an upper chamber 3 and a lower chamber 4 as a raw water chamber. A plurality of filter elements 6 extending downward from the partition plate with its upper end portion penetrating through the partition plate 5 are suspended from the partition plate 5. The upper end of each filter element 6 is formed as a protrusion 7 projecting above the partition plate 5, and an opening 8 is provided at the upper end of the protrusion 7. As shown in FIGS. 2A and 2B, the projecting portion 7 is covered with a gap between the projecting portion 7 and an opening of the projecting portion 7 between itself and the projecting portion 7. An outer cylinder 10 forming a flow path 9 reaching 8 is provided. In the present embodiment, the outer cylinder 10 is supported and fixed to the protruding portion 7 by a plurality of stays 11 so that the outer cylinder 10 can be handled integrally with the filter element 6 together with the protruding portion 7. The outer cylinder 10 is provided with an opening 12 at a position below the opening 8 of the protruding portion 7 so as to communicate the flow path 9 with the outside of the outer cylinder 10, and the opening 12 of the protruding portion 7 is smaller than the opening 8. An upper hole is provided with a small hole 13 that constantly communicates the inside and outside of the outer cylinder 10. In the present embodiment, the small hole 13 is formed in the upper plate portion 10 a of the outer cylinder 10, but need not be limited to this position as long as it is above the opening 8 of the protruding portion 7. In the present embodiment, the opening 12 of the outer cylinder 10 is formed as an opening at the lower end of the outer cylinder 10, and is formed by a gap between the cylindrical portion 10 b of the outer cylinder 10 and the outer peripheral surface of the protrusion 7. The flow path 9 communicates with the outside of the outer cylinder 10 through the opening 12, but as shown in another form in FIG. 3, the outer cylinder 31 is fixed to the partition plate 5, and the outer cylinder 31 is fixed. A hole 32 having a communication function equivalent to that of the opening 12 may be provided at a position below the opening 8 of the protrusion 7 in the cylindrical portion 31b. Also in this case, a small hole 33 that constantly communicates the inside and outside of the outer cylinder 31 is provided at a position above the opening 8 of the protruding portion 7 of the outer cylinder 31, for example, at the upper plate portion 31 a of the outer cylinder 31 as illustrated. Provided.
[0013]
As described above, between the outer cylinder 10 (31) arranged with a gap with respect to the projection 7 of the filter element 6 and the projection 7, the periphery of the outer cylinder 10 (31) and the opening of the projection 7 are provided. 8, and further, a flow path 9 communicating with the inside of the filter element 6 is formed, and a small hole 13 (33) is provided in the outer cylinder 10 (31) which constantly communicates inside and outside of the outer cylinder.
[0014]
As shown in FIG. 1, raw water 14 (for example, condensed water in a power plant) is introduced into the lower chamber 4 of the filtration tower 2 via a raw water inlet pipe 15 and a raw water inlet valve 16 as shown in FIG. The filtered water is filtered by the filter element 6, and the filtered water flows from the inside of each filter element 6 into the upper chamber 3 through the upper opening 8, and is filtered from the upper chamber 3 through the filtered water outlet valve 17 and the filtered water outlet pipe 18. Released as water 19. Further, a pipe and a valve for backwashing are connected to the filtration tower 2, and the lower chamber 4 can be supplied with backwash water 22 via a backwash water pipe 20 and a backwash water valve 21. The water in the lower chamber 4 can be drained from the lower chamber 4 as a drain 25 through a drain pipe 23 and a drain valve 24. In this embodiment, the backwash water pipe 20 and the backwash water valve 21 are provided so that the backwash water 22 can be supplied into the lower chamber 4 of the filtration tower 2. Since the backwashing operation performed by supplying backwashing water into the inside is basically unnecessary, these backwashing pipes and valves may be omitted. Further, in the present embodiment, the backwash air pipe 27 can be connected to the upper chamber 3 via the backwash air valve 26 and the filtered water outlet pipe 18. , The upper chamber 3 can be opened to the atmosphere, and the pressurized backwash air 28 can be supplied into the upper chamber 3. In the present embodiment, the opening of the atmosphere in the upper chamber 3 and the supply of pressurized air to the upper chamber 3 are performed through the common backwash air valve 26 and the backwash air pipe 27. , Can also be provided individually.
[0015]
In the present invention, the type of the filter element 6 is not particularly limited as long as the above-described structure can be adopted, and various filter elements such as a pleated type, a precoat type, and a hollow fiber type can be used. In addition, the use of the filtration device according to the present invention is not particularly limited. For example, as described above, the filtration device can be applied to condensate filtration in a power plant.
[0016]
The backwashing step in the filtration device 1 configured as described above is performed, for example, as follows. Although the following description is made with respect to the outer cylinder structure shown in FIG. 2, substantially the same operation is performed in the outer cylinder structure shown in FIG.
At the end of the filtration process, the inside of the filtration tower 2 is full, the lower chamber 4 is filled with raw water, and the upper chamber 3 is filled with filtered water. When the backwashing step is started after the filtration step, first, the backwashing air valve 26 is opened to open the upper chamber 3 to the atmosphere, and the drain valve 24 is opened to open the lower chamber 4 through the drain pipe 23. Drain the water inside. At the time of draining, the water in the upper chamber 3 is also drained to the lower chamber 4 through each filter element 6 as the water in the lower chamber 4 is discharged, and the water level in the upper chamber 3 that is open to the atmosphere gradually decreases. . When the water level falls below the position of the small hole 13 of the outer cylinder 10, the flow path 9 formed by the gap between the outer cylinder 10 and the projecting portion 7 of the filter element 6 passes through the small hole 13 which is always open. Since the air is naturally opened to the atmosphere, the siphon phenomenon does not act on the flow path 9. As a result, the water level in the upper chamber 3 drops to the level of the opening 8 at the upper end of the protruding portion 7, but does not drop any more, resulting in the state shown in FIG. The water in the lower chamber 4 continues to be discharged until the inside of the lower chamber 4 becomes substantially empty, but the water remains on the partition plate 5 of the upper chamber 3, and the state shown in FIG. It becomes. That is, due to the function of the small hole 13 which is always open, all of the filtered water that was initially present in the upper chamber 3 is not discharged, and part of the filtered water is used for the subsequent backwashing. A considerable amount of water is left in the upper chamber 3.
[0017]
From the state shown in FIG. 5, pressurized backwash air is then supplied into the filtration tower 2 via the backwash air pipe 27, and remains in the upper chamber 3 as shown by the arrow in FIG. The filtered water that has been pushed by the pressurized air flows into the filter element 6 from the flow path 9 between the outer cylinder 10 and the protrusion 7 of the filter element 6 through the upper end opening 8 of the protrusion 7, It is quickly discharged from the element 6 into the empty lower chamber 4. Due to this rapid flow (high backwash flow rate), impurities trapped on the outer surface of the filter element 6 are peeled off, and an excellent initial backwash effect is obtained.
[0018]
In order to efficiently backflow the residual water by the supplied pressurized air during the backwashing, it is preferable that the diameter of the small hole 13 is relatively small. When opening the siphon, it is only necessary to open the atmosphere, so a small hole 13 with a small diameter is sufficient. When the residual water flows backward, the resistance of the small hole 13 is increased to reduce the compressed air. It is desirable that the short circuit be minimized through the hole 13 so that the residual water around the hole 13 is pressed by the pressurized air and quickly flows into the filter element 6 from the upper end opening 8 of the protrusion 7. By appropriately forming the diameter to be small, it is possible to achieve both the opening to the atmosphere for the siphon cutting and the rapid backflow in a desirable form.
[0019]
As described above, the configuration having the outer cylinder 10 having the small holes 13 which are always open allows the first backwashing operation to be efficiently performed, and causes a rapid backflow from the first backwashing operation. Excellent backwash effect can be obtained. In addition, since the filtered water existing in the upper chamber 3 from the beginning can be used for the backwashing operation, the amount of the backwash waste liquid can be reduced.
[0020]
After the first backwashing operation as described above, backwash water is introduced into the upper chamber 3 from the filtered water outlet pipe 18, and the backwashing water is returned to the upper chamber 3 to the level of the upper end opening 8 of the protruding portion 7 as described above. The backwashing operation of holding the washing water, then supplying backwashing air into the upper chamber 3, and discharging the backwashing water through the filter element 6 may be appropriately repeated a plurality of times. Since the backwash operation involving rapid backflow is repeated a plurality of times including the first time, a sufficiently high backwash effect can be obtained.
[0021]
FIGS. 6A and 6B show a filter element portion and an outer cylinder portion of a filtration device according to another embodiment of the present invention. The present embodiment shows a case where the outer cylinder is configured as a common outer cylinder 42 for a plurality of (four in the illustrated example) filter elements 41, and the plurality of filter elements 41 This shows a case in which the common outer cylinder 42 is fixed to the upper end protruding portion 43 and can be handled as an integral member. In the illustrated example, only one normally-open small hole 44 is provided at the center of the upper plate of the outer cylinder 42, but a plurality of small holes 44 may be provided. Further, a partition wall 45 extending in a cross shape is provided in the outer cylinder 42 so that a uniform flow path is formed around the upper end projecting portion 43 of each filter element 41. However, a structure without the partition wall 45 is also possible.
[0022]
Such a configuration is particularly effective in the following cases. For example, the hollow fiber filter element is generally configured to have a relatively large diameter, and the pleated filter element and the precoated filter element are configured to be considerably thinner. For example, the mounting occupied cross-sectional area of one hollow fiber filter element corresponds to the mounting occupied cross-sectional area of four pleated or precoated filter elements. Therefore, when the existing filtering device uses a hollow fiber filter element, and when the type of the filter element is changed to a pleated type or a pre-coated type filter element, the mounting portion for one hollow fiber filter element is used. Thus, it is possible to mount a plurality of other types of filter elements in a bundled state. In applying the present invention in such a case, it is better to provide a common outer cylinder for a bundle of a plurality of filter elements than to provide an outer cylinder for each pleated or pre-coated filter element. The number of parts can be reduced, and the overall structure can be simplified. In addition, since the filter elements can be handled in a bundle, the handling and installation in the filtration tower become easy. Even when such a configuration is employed, the same excellent backwashing effect as described above can be obtained for backwashing.
[0023]
【The invention's effect】
As described above, according to the filtration device of the present invention, the projection from the partition plate at the upper end of the filter element, the outer cylinder that covers the projection with a gap is provided, and the normally open small hole is formed in the outer cylinder. As a result, a predetermined amount of filtered water that was initially present in the upper chamber remains, and can be effectively used for backwashing by rapid backflow. Efficient backwashing can be performed. As a result, the effect of backwashing can be improved, and the amount of backwash waste liquid can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a filtration device according to an embodiment of the present invention.
2 is an enlarged partial longitudinal sectional view (A) and a plan view (B) of a filter element portion and an outer cylinder of the device of FIG.
FIG. 3 is a schematic configuration diagram showing an outer cylinder according to another embodiment different from FIG. 2;
FIG. 4 is a schematic configuration diagram showing a state in which water is drained to a level of an upper end opening of a filter element protrusion of the apparatus of FIG. 1;
FIG. 5 is a schematic configuration diagram illustrating a state when all the water in the lower chamber is further drained from the state in FIG. 4 and a state when pressure is applied to residual water in the upper chamber.
FIG. 6 is a partial longitudinal sectional view (A) and a plan view (B) when a common outer cylinder is provided for a plurality of filter elements.
FIG. 7 is a schematic configuration diagram of a conventional filtration device.
FIG. 8 is a partial longitudinal sectional view when an outer cylinder without a small hole is provided.
FIG. 9 is a partial longitudinal sectional view when a check valve is provided in the outer cylinder.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Filtration apparatus 2 Filtration tower 3 Upper chamber 4 Lower chamber 5 Partition plate 6 Filter element 7 Projection part 8 Projection opening 9 Flow path 10 Outer cylinder 10a Upper plate part 10b Outer cylinder cylindrical part 11 Stay 12 Outer cylinder Lower end opening 13 of normally open small hole 14 Raw water 15 Raw water inlet pipe 16 Raw water inlet valve 17 Filtered water outlet valve 18 Filtered water outlet pipe 19 Filtered water 20 Backwashing water pipe 21 Backwashing water valve 22 Backwashing water 23 Drainage pipe 24 Drain valve 25 Drain 26 Backwash air valve 2
27 Backwash air pipe 28 Backwash air 31 Outer cylinder 31a Upper plate 31b of outer cylinder Cylindrical part 32 of outer cylinder 33 Hole as opening of outer cylinder 33 Small hole 41 always open Filter element 42 Common outer cylinder 43 Upper end protrusion 44 Small hole 45 Partition wall in outer cylinder

Claims (4)

The filter tower is divided into an upper chamber as a filtered water chamber and a lower chamber as a raw water chamber by a partition plate, and a filter extending downward from the partition plate with an upper end portion penetrating the partition plate. In the filtration device with the element suspended, the upper end of the filter element is protruded above the partition plate to provide an opening in the protruding portion. An outer cylinder forming a flow path leading to the opening is provided, and an opening for communicating the flow path with the outside of the outer cylinder is provided at a position below the opening of the protrusion at the outer cylinder; A filter which is provided at a position above the opening of the portion so as to constantly communicate the inside and outside of the outer cylinder. The filtering device according to claim 1, wherein the outer cylinder is fixed to an upper end of a filter element. The filtering device according to claim 1, wherein the outer cylinder is fixed on a partition plate. The filtering device according to claim 1, wherein the outer cylinder is configured as a common outer cylinder for a plurality of filter elements.

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