JP3797557B2 - Filtration equipment using floating media - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a filtration device for efficiently filtering raw water containing a considerable amount of inflow water and residue from a first sedimentation basin in sewage.
[0002]
[Prior art]
Conventionally, a filter device that forms a filter medium layer by filling a floating filter medium in a horizontally installed cylindrical filtration tank and filters raw water in an upward flow is disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-293307. As known in the art. This proposal employs a mechanism that allows raw water to flow into the upper filtration chamber from a rectifying plate disposed at the lower part of the filtration tank as a filtration method. However, the filtration device is not provided with a mechanism for removing dust attached to the current plate. Therefore, the filtration target liquid of the filtration device is limited to raw water having a relatively high degree of clarification and free from dust such as residue.
[0003]
[Patent Document 1]
JP-A-2001-293307 [0004]
[Problems to be solved by the invention]
However, although the filtration device described in the invention of Patent Document 1 is relatively suitable for filtration of a stock solution having a high degree of clarity, the raw water containing a considerable amount of residue, including the inflow water of the first sedimentation site in sewage. When filtering wastewater, it is difficult to filter unless a pre-treatment device such as a dust dust remover is provided because the residue and coarse dust contained in the raw water will adversely affect the filtration device. was there.
[0005]
Therefore, the present invention provides an efficient filtration operation and apparatus for raw water containing a considerable amount of residue, including the inflow water of the first sedimentation site in the sewage, without providing a pretreatment device such as a dust remover. It aims at providing the filtration apparatus using the floating filter medium which can be enlarged.
[0006]
[Means for Solving the Problems]
In the present invention, a floating filter medium is filled in a horizontal cylindrical filtration tank to form a filter medium layer, raw water is supplied from the bottom of the filter tank, and treated water separated by the filter medium layer is supplied from the top of the filter tank. In the filtration device to be taken out, a cylindrical screen is arranged at the lower part of the filtration tank, and a screw conveyor is installed in the screen , a raw water inlet is opened at the start end side of the screw conveyor, and a drain outlet is provided at the end side. Is an opening . Furthermore, in the case of a large filtration tank, a filtering device using a floating filter material that opens a plurality of raw water inlets and a plurality of drain outlets at the bottom of the screen so as to balance the raw water inflow amount. By solving this problem, the above-mentioned problems are solved.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The filtration mode of the filtration apparatus using the floating filter medium according to the present invention will be described according to the flow of raw water. The first step of the filtration device is to operate the raw water pump to filter raw water containing coarse debris such as scum and distribute it from the raw water tank to the lower part of the horizontal cylindrical filtration tank via the raw water supply valve. This is a raw water supply step for flowing raw water into a cylindrical raw water chamber. If the raw water tank is located above the filtration device and the head can be press-fitted, the raw water may be allowed to flow from the raw water tank into the raw water chamber without using the raw water pump. The raw water supplied from the raw water inlet to the raw water chamber passes through a screen having a large number of small holes in a cylindrical structure provided in the raw water chamber, and then flows into a filtration chamber formed of a floating filter medium and formed with a filter medium layer. . However, coarse dust such as scum contained in the raw water is captured by a large number of small holes opened in the inner peripheral surface of the screen when passing through the screen. The raw water that has passed through the screen passes through the filter medium layer in an upward flow, and then passes from the current plate installed at the top of the filtration tank to the filter plate with a large number of small holes provided to prevent the filter medium from flowing out. Flow into. When the raw water flows into the water collection chamber, the solid matter remaining in the raw water from which coarse dust has been removed by the trapping action of the screen is composed of a floating filter medium while passing upward through the filtration chamber. Captured by the filter media layer. The raw water, which has been clarified by capturing coarse dust such as residue and solids by the screen and filter medium layer of the filtration chamber, flows out from the water collection chamber to a treated water pipe disposed above the filtration tank. The raw water flowing into the treated water pipe is stored as treated water in a treated water tank installed outside the filtration tank from a treated water valve connected to the treated water pipe.
[0008]
A description will be given of the conveyance of coarse trash such as residue collected on the inner peripheral surface of a screen having a large number of small holes in a cylindrical structure provided in the raw water chamber. If the captured coarse garbage including debris is left unattended, the screen will be clogged, which will hinder the supply of raw water to the filtration chamber. In order to avoid this, coarse dust adhering to the inner surface of the screen is forcibly scraped off with screw blades of a screw conveyor disposed on the inner surface of the screen. The coarse garbage scraped off is carried to the discharge port located at the tip of the screw conveyor by the rotation of the screw blades, and is periodically deposited on the discharge valve attached to the outlet of the discharge port, and accumulated at the discharge port. Coarse debris such as residue is discharged outside the filtration tank. In this way, by operating the screw conveyor in parallel with the filtration operation, coarse dust such as residue can be removed from the inner peripheral surface of the screen, and the screen is clogged even during the filtration operation. There is no.
[0009]
Next, a description will be given of a method for cleaning a floating filter medium that is clogged due to solid matter or the like in the filter medium layer in the filtration tank during the continuation of the filtration operation. In the filtration tank of the present filtration device, a washing device composed of a stirrer and an air diffuser is disposed to wash the clogged floating filter medium. When clogging is detected due to an increase in pressure in the filtration chamber or the like, in order to continue a stable filtration operation, it is necessary to remove the solid matter fixed to the floating filter medium with a washing device. Before starting cleaning, the raw water pump and screw conveyor are stopped. After the operation of the raw water pump and the screw conveyor is stopped, it is preferable from the viewpoint of the cleaning effect that the raw water remaining in the filtration tank is replaced with the treated water or the secondary treated water in the sewage treatment plant. Therefore, after stopping the operation of the raw water pump and the screw conveyor, the discharge valve is opened to discharge the raw water in the filtration chamber. After the raw water has been discharged, as a preparation for the cleaning operation, the cleaning water pump is operated to supply cleaning water composed of treated water or secondary treated water from the treated water tank to the filtration tank via the cleaning valve. . In this way, after replacing the raw water remaining in the filtration tank with washing water, the washing water pump is operated in parallel with the operation of the washing water pump, the supply of compressed air to the air diffuser, and the operation of the agitator. A synergistic effect such as the drainage function by, the swirling and stirring function by the jet output of bubbles from the nozzle arranged in the diffuser, and the swirling and stirring function by the stirring blades of the stirrer work on the washing water inside the filtration tank, The solid matter adhering to the floating filter medium in the filtration operation is efficiently removed and drained out of the filtration tank together with the wash water from the drain valve connected to the end of the treated water pipe. When the filtration operation is resumed after finishing the filtration process of the filter medium layer as described above, the clear treated water is taken out from the raw water again by the floating filter medium that is a component of the filter medium layer regenerated in the washing process. Is done.
[0010]
【Example】
FIG. 1 is a front view of a filtration apparatus according to the present invention. FIG. 2 is a side view of FIG. FIG. 3 is a schematic diagram of the raw water inlet 6 and the drain outlet 7 in the screen 4 part arranged at the lower part of the filtration tank 1. FIG. 4 is a side view of a conventional filtration device. FIG. 5 is a perspective view of the floating filter medium 2. The structure of the filtration apparatus using the floating filter medium according to the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 1 denotes a filtration tank, which is provided with a cylindrical tank having a sealed structure. The filtration tank 1 includes a raw water chamber 8 corresponding to the first inflow portion of the raw water, a filtration chamber 9 that captures solids in the raw water flowing in from the raw water chamber 8, and a collected water into which the filtered raw water flows as treated water. The chamber 12 is configured. The raw water chamber 8 includes a raw water inlet 6 which is an inlet of raw water, a screen 4 for catching debris such as debris contained in the raw water, and debris such as debris collected by the screen 4. It comprises a screw conveyor 5 for discharging and a drain discharge port 7 which is a discharging portion for the above-mentioned garbage. The filtration chamber 9 includes a filter medium layer 3 composed of a floating filter medium 2 that captures solids in raw water, and treated water that has been purified by capturing solid substances in the raw water in the filter medium layer 3 into a water collection chamber 12. It comprises a stirrer 18 and an air diffuser 19 for cleaning the flow straightening plate 10 and the filter medium layer 3 to be introduced. Further, the water collecting chamber 12 is composed of a water collecting plate 11 having a large number of small holes provided for preventing the floating filter medium 2 from flowing out, and a water collecting tube 25 through which the raw water in the water collecting chamber 12 flows into the treated water pipe 13. The In FIG. 1, reference numeral 26 is a raw water tank for storing raw water, reference numeral 27 is a raw water pump for supplying raw water from the raw water tank 26 to the filtration tank 1, reference numeral 28 is a washing water pump, reference numeral 29 is a treated water tank for storing treated water, Reference numeral 30 denotes a drain valve, reference numeral 31 denotes a treated water valve, reference numeral 32 denotes a raw water supply valve, and reference numeral 33 denotes a cleaning valve.
[0011]
As shown in FIG. 1, the filtration tank 1, which is a sealed cylindrical tank, has a horizontal structure and a curved structure in which both side surfaces bulge outward. When the filtration tank 1 has a horizontal structure, the volume ratio of the raw water flowing into the filtration tank 1 with respect to the unit length of the screw blades 15 disposed in the screw conveyor 5 is the vertical structure of the filtration tank 1. Smaller than that. Therefore, by making the filtration tank 1 into a horizontal structure, the conveyance efficiency of the screw conveyor 5 installed in the filtration tank 1 is increased from that of the filtration tank 1 having a vertical structure, and the screw conveyor 5 can be downsized. It is economical in terms of equipment cost and installation area. Moreover, if it is made into the curved surface structure which swells the both sides | surfaces of the filtration tank 1 outside, the tank internal resistance which flows through the phase part in the filtration tank 1 will become small. Therefore, by making the both sides | surfaces of the filtration tank 1 into the curved surface structure which swells outside, the flow of the raw | natural water at the time of a filtration process becomes smooth, and the stable filtration effect | action can be anticipated.
[0012]
The screen 4 disposed in the lower part of the filtration tank 1 has a structure in which a member having a large number of small holes is formed into a cylindrical shape, and has a raw water inlet 6 corresponding to the raw water inlet of the raw water chamber 8 on both end surfaces. A drain discharge port 7 for discharging coarse dust such as residue is opened. The screen 4 has a function of capturing coarse dust such as scum contained in the raw water and a function of smoothly supplying the raw water from the screen 4 to the filtration chamber 9. In addition, when raw | natural water flows in into the filtration chamber 9, since many small holes are arrange | positioned in the surrounding surface of the screen 4, raw | natural water flows in efficiently into the filtration chamber from the internal peripheral surface of the screen 4. FIG. In addition, in order to increase the capture efficiency of the garbage and the passage efficiency of the raw water, the diameter of the small holes opened in the screen 4 is the size of the small holes provided in the properties of the garbage contained in the raw water and the upper water collecting plate. It is decided by. However, when the raw water passes through the filtration chamber, there is a risk of clogging with dust in the water collecting plate 10 part. Therefore, the diameter of the small hole opened in the screen 4 is the diameter of the small hole provided in the upper water collecting plate 10. Need to be smaller.
[0013]
The screw conveyor 5 is attached to the inner surface of the screw shaft 22 and the screen 4 to which the screw driving device 21 that rotates the screw blade 15 and the driving force of the screw driving device 21 are transmitted and the screw blade 15 is fixed. The screw blade 15 for forcibly scraping coarse dust such as residue to the discharge port 16, the discharge port 16 for transporting coarse dust such as residue, and the like deposited on the discharge port 16. It is constituted by a discharge valve 17 that discharges coarse dust such as residue to the outside of the filtration tank 1. The outer diameter of the screw blade 15 is slightly smaller than the inner peripheral diameter of the screen 4. An elastic scraper (not shown) may be attached to the tip of the screw blade 15. This is because the elastic scraper is pressed against the inner peripheral surface of the screen 4 when the screw blade 15 is rotated, so that not only the scraping efficiency but also the conveying efficiency is improved. The screw blade 15 having an outer diameter slightly smaller than the inner peripheral diameter of the screen 4 and provided with an elastic scraper at the tip thereof, as described above, removes coarse dust such as screen residue captured by the screen 4. 4 has a function to surely scrape off from the inner peripheral surface of 4 and a function to transport coarse scraps such as scum removed to the discharge port 16. In addition, in order to continue supply of the stable raw water, the screw conveyor 5 is also operated in parallel during the raw water filtration operation. That is, during the raw water filtration operation, the screw conveyor 5 is operated in parallel, so that during the filtration operation, coarse dust such as residue and the like which is to be accumulated on the inner surface of the screen is always scraped with the screw blade 15. Therefore, even during the filtration operation, the screen 4 can be stably filtered without clogging.
[0014]
The discharge port 16 is located at the tip of the screw conveyor 5 and has a function of storing coarse dust such as residue that has been carried from the inner peripheral surface of the screen 4 by the screw blades 15. Further, a discharge valve 17 is connected to a lower end portion of the discharge port 16. The discharge valve 17 may be a manual valve or an automatic valve, and has a function of discharging coarse dust such as residue remaining in the discharge port 16 to the outside of the filtration tank 1. If the coarse trash including the residue etc. accumulated at the discharge port 16 is left unattended, the transfer function of the screw conveyor 5 is hindered. Therefore, it is necessary to periodically open the discharge valve 17 and discharge coarse dust including sediment and the like. Therefore, when the discharge valve 17 is opened, filtration pressure is generated at the discharge port 16 during the filtration operation, so that coarse dust such as residue accumulated at the discharge port can be easily removed from the filtration tank 1 by the filtration pressure. Can be discharged together with raw water. Further, when coarse dust such as residue accumulates on the discharge port 16, the filtration operation can be automated by opening and closing the discharge valve 17 with a sensor (not shown) or a timer signal.
[0015]
As described above, the cylindrical screen 4 having the function of capturing coarse dust such as scum contained in the raw water and the function of smoothly supplying raw water to the filtration chamber 9, and the scum captured by the screen 4 The screw conveyor 5 having the function of scraping coarse dust such as from the inner peripheral surface of the screen 4 and the function of scraping coarse dust such as scum to the discharge port 16, and the residue stored in the discharge port 16 The filtration device in which the discharge valve 17 having the function of discharging the coarse dust out of the filtration tank 1 is disposed in the filtration tank 1, the inflow of the first sedimentation site in the sewage without the need for a pre-treatment device such as a screen dust remover. It is possible to capture garbage such as residue from raw water including a considerable amount of residue including water, and to easily discharge the collected garbage and perform efficient filtration operation. Conventionally, a pretreatment device such as a screen dust remover is provided separately from the filtration device for the raw water, and the filtration operation is performed. However, the filtration device of the present invention having a residue removal function does not require a separate pretreatment device such as a residue dust remover. Therefore, this filtration apparatus becomes a compact structure, and an installation cost becomes cheap because an installation area becomes small. In addition, operation management is facilitated due to a reduction in the number of devices attached to this device.
[0016]
The filter medium layer 3 is composed of a large number of floating filter media 2 in the upper part of the filtration tank, and has a function of capturing solids contained in the raw water when the raw water passes through the filter medium layer 3. In addition, since this filtration apparatus is a structure which performs a filtration effect | action by an upward flow, the specific gravity of the floating filter medium 2 to be used is preferable to be 1.0 or less, but if it floats by an upward flow, even if it is a granular filter medium, a fiber Any filter medium can be used regardless of shape and material. The rectifying plate 10 is disposed above the filter medium layer 3 in parallel with the upward flow of raw water, and has a function of allowing the raw water to flow uniformly over the entire surface of the water collection chamber 12. Furthermore, by uniformly increasing the raw water, the flow rate per unit area of the raw water passing through the filter medium layer 3 is averaged, and the filtering action in the filter medium layer 3 is stabilized.
[0017]
The water collecting chamber 12 includes a water collecting plate 11 and a water collecting pipe 25. The water collecting plate 11 has a structure in which a plate having a large number of small holes is disposed over the entire surface of the filtration tank 1, and has a function of preventing the floating filter medium 2 from flowing out of the filtration chamber 9, and the raw water is uniformly collected into the water collecting chamber. 12 has the function of being incorporated in Further, a plurality of water collecting pipes 25 are arranged at the upper part of the water collecting chamber 12, and have a function of flowing raw water in the water collecting chamber 12 to the treated water pipe 13 and a support function for fixing the treated water pipe 13 above the filtration tank 1. Have. The treated water pipe 13 is a cylindrical pipe and has a connecting short pipe connected to the water collecting pipe 25 at the bottom. Moreover, when the treated water pipe 13 is provided in the upper part of the filtration tank 1, the flow velocity in the pipe when the treated water passes through the water collection pipe portion is averaged, and this averaged treated water flow becomes the raw water rising in the filtration chamber 9. The filter medium layer 3 constituting the filtration chamber 9 can be expected to have a stable filtration effect.
[0018]
A stirrer 18 disposed in the longitudinal direction of the filtration tank 1 and in the center of the lower part is composed of a stirring shaft 14, stirring blades 20 attached to several portions of the stirring shaft 14, and a stirring motor 26 that rotates the stirring shaft. The washing water in the filtration tank 1 has a function of stirring. Further, the air diffusion pipe 19 disposed in the longitudinal direction of the filtration tank 1 and in the center of the lower part is constituted by a pipe and a nozzle (not shown) attached to the pipe, and the washing water is generated by bubbles ejected from the nozzle. It has a stirring function and a cleaning function for the filter medium layer 3. The stirring device including the stirrer 18 and the aeration tube 19 can be expected to have a reliable cleaning effect due to the synergistic action of the turning force and stirring force by the stirring blade 20 and the turning force and stirring force caused by bubbles from the aeration tube 19.
[0019]
FIG. 2 is a side view of FIG. The screen 4 disposed at the center of the lower part of the filtration tank 1 can flow the raw water evenly to the left and right with respect to the filter medium layer 3 viewed from the side. Further, as shown in the figure, the stirring blade 20 of the stirrer 18 is disposed on the left side of the lower part of the filtration tank 1, and the aeration tube 19 is disposed on the right side of the lower part of the filtration tank 1. In addition, arrangement | positioning of the diffuser tube 19 and the stirrer 18 is not limited to the position of this figure, Each may be an other side. The direction of the swirling flow caused by the rotation of the stirrer 18 may be the same direction as that of the swirling flow caused by the air diffuser 19 or may be reversed. That is, in the case of the same direction, the swirl flow is amplified and a strong cleaning effect is generated. In the case of the reverse direction, a turbulent flow is generated inside the filtration layer 3 to promote irregular rotation and vibration in the floating filter medium 2, thereby cleaning effect. Can be expected. In addition, the forward / reverse rotation of the stirrer 18 may be repeated by a timer operation. By rotating the stirrer 18 in the forward and backward directions, the impact force between the floating filter media 2 is increased by the swirling flow or the reversal flow in the floating filter media 2 and the cleaning effect is promoted.
[0020]
FIG. 3 is a schematic view of the raw water inlet 6 and the drain outlet 7 in the screen 4 portion disposed in the lower part of the filtration chamber 9. By changing the direction of the adjacent screw blades 15, that is, as shown in FIG. It gathers to the drain outlet 7 from the left and right. In the case of a large filtration tank 1, if this screw mechanism and a plurality of drain discharge ports 7 are provided in the screen 4 part, dusts such as residue are not concentrated on a specific part of the screen 4 part. Further, if a plurality of raw water inlets 6 are provided in the screen 4 part, the raw water can be uniformly introduced over the entire surface of the screen 4. Therefore, by providing the screw mechanism, the plurality of drain discharge ports 7 and the plurality of raw water inlets 6 in the screen 4 part, stable raw water supply is performed, and the size of the filtration device can be increased.
[0021]
FIG. 4 is a side view of a filtration device used as a conventional device. The filtration device employs a mechanism in which raw water flows into the upper filtration chamber 9 from the rectifying plate 22 disposed at the lower part of the filtration tank 1. However, since the filtration device is not equipped with a mechanism for removing the dust adhering to the current plate 22, it is suitable for filtration of a stock solution having a relatively high degree of clarity. There is a problem that it is not suitable for filtration.
[0022]
FIG. 5 is a perspective view of the floating filter medium 2 and shows the floating filter medium 2 according to an embodiment of the present invention. A polypropylene fiber and a fiber in which polypropylene fiber is coated with polyethylene are heat-sealed and formed into a sheet shape having a thickness of about 3 mm and cut into a size of 5 to 10 mm square. The fiber filter medium 5 has a specific gravity of approximately 0.9 and a porosity of 90% or more, and has a high strength based on polypropylene and is resistant to wear. Note that the type of the floating filter medium 2 is not limited to that described above, and the floating filter medium 2 of each specification, each type, and each size corresponding to the properties and throughput of raw water can be used.
[0023]
【The invention's effect】
As described above, according to the present invention, a cylindrical screen is disposed in the lower part of the filtration tank, and the raw water inlet is opened in the screen, so that garbage such as scum contained in the raw water is captured. it can. Then, by installing a screw conveyor in the screen and opening a drain discharge port in the screen, the captured garbage can be easily discharged to the outside of the filtration tank. Also, by opening a plurality of raw water inlet and a plurality of drain outlet in the lower portion of the upper Symbol screen can increase in size of the stable raw water supply available and becomes the filtration device. The filtration apparatus using the floating filter medium according to the present invention having the above-described function is not limited to a pre-treatment device such as a screen dust remover, and a considerable amount of screen residue including inflow water of the first sedimentation site in sewage. Efficient filtration operation is possible for raw water containing water.
[Brief description of the drawings]
FIG. 1 is a front view of a filtration apparatus using a floating filter medium according to the present invention.
FIG. 2 is a side view of a filtration device using a floating filter medium according to the present invention.
FIG. 3 is a schematic view of a raw water inlet of a filtration apparatus using a floating filter medium according to the present invention.
FIG. 4 is a side view of a conventional filtration device using a floating filter medium.
FIG. 5 is a perspective view of the floating filter medium of the filtration apparatus using the floating filter medium according to the present invention.
[Explanation of symbols]
1 Filtration tank 2 Floating filter medium 3 Filter medium layer 4 Screen 5 Screw conveyor 6 Raw water inlet 7 Drain outlet

Claims (2)

A floating filter medium (2) is filled in a cylindrical filter tank (1) installed horizontally to form a filter medium layer (3), and raw water is supplied from the bottom of the filter tank (1) to obtain a filter medium layer (3 ), A cylindrical screen (4) is disposed at the bottom of the filtration tank (1), and a screw conveyor (5 ) is disposed on the screen (4). ), A raw water inlet (6) is opened on the start end side of the screw conveyor (5), and a drain discharge port (7) is opened on the end side. apparatus. Filtration apparatus using a floating filter media according plurality of raw water inlet (6) and a plurality of drain outlet (7) in claim 1, characterized in that an opening at the bottom of the screen (4).

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