WO2015052906A1

WO2015052906A1 - Filtration device

Info

Publication number: WO2015052906A1
Application number: PCT/JP2014/005068
Authority: WO
Inventors: 崇史橋本; 伸浩青木
Original assignee: メタウォーター株式会社
Priority date: 2013-10-08
Filing date: 2014-10-03
Publication date: 2015-04-16
Also published as: JP2015073933A

Abstract

This filtration device is provided with: a filtration unit having a filtration material; a pump; piping for water to be treated, the piping connecting the discharge opening of the pump and the filtration unit; a treated-water storage tank having a treated-water flow outlet; treated-water piping for connecting the treated-water storage tank and the filtration unit at a position below the treated-water flow outlet; a siphon pipe having one end connected to the piping for water to be treated and the other end located below the vertical position of the treated-water flow outlet, the siphon pipe being extended vertically upward to a position higher than the position of the treated-water flow outlet by a predetermined distance; a control unit for controlling the drive and stop of the pump; a reverse cleaning start detection means for detecting the start of reverse cleaning of the filtration material, the start of reverse cleaning being initiated by the formation of a siphon; and a reverse cleaning completion detection means for detecting the timing of the completion of the reverse cleaning.

Description

Filtration device

The present invention relates to a filtration device, and more particularly to a filtration device having a backwashing mechanism using a siphon tube.

In order to obtain purified water such as drinking water, various water treatments including filtration treatment are generally performed. Among them, a membrane filtration device that physically separates suspended substances and colloids in water by passing water through the filtration membrane is highly convenient and is frequently used in water supply facilities. On the other hand, in the membrane filtration device, the filtration membrane becomes dirty and clogged in the process of filtration, and therefore it is necessary to periodically clean and replace the filtration membrane itself. This regular cleaning includes physical cleaning and chemical cleaning. In physical cleaning, clean water such as membrane filtration water is passed through the filtration membrane from the direction opposite to the filtration direction, and the filtration membrane is back-washed. There is.

Here, particularly in developing countries and the like, from the viewpoint of easily producing purified water at a low cost, a filtration device with a simple device structure and easy operation management is required. Therefore, the backwashing mechanism for backwashing filter media such as filtration membranes is also required to simplify the device structure and facilitate the operation management.

In response to such demands, a siphon-type backwash device that automatically operates when the filter media reaches a predetermined clogged state in a filtration device and can restore the filtration function by backwashing the filter media is conventionally provided. A filtration device provided has been proposed (see, for example, Patent Document 1). According to the filtration device provided with the siphon-type backwash device described in Patent Document 1, a filtration tank containing the filtration material, a raw water supply pipe for supplying raw water from above to the filtration material in the filtration tank, and a filtration tank Is provided with a backwash water storage tank that is formed above and stores filtered water as backwash water, and a siphon tube that communicates with the filter tank above the filter medium. When the pressure difference reaches a predetermined value, a siphon is automatically formed, and the filtrate in the backwash water storage tank flows to the outside through the filter tank and the siphon tube. Therefore, according to the filtration device provided with the siphon type backwash device described in Patent Document 1, the filter medium can be automatically backwashed with a simple device configuration.

JP 58-14911 A

Here, the filtration device described in Patent Document 1 is a gravity filtration device that supplies raw water to the filter medium from above and performs filtration using gravity. And in the filtration apparatus of patent document 1 using gravity filtration, since the water level in a siphon pipe | tube and the water level in a filtration tank become equal before a siphon is formed (namely, during filtration), raw water supply It was necessary to arrange the tube above the top of the siphon tube, and sufficient space was required above the filter medium. Therefore, the filtration device using the siphon type backwash device described in Patent Document 1 has a problem that the installation place is limited.

In response to such a problem of installation location, the present inventors do not use a gravity filtration method as a filtration method, but supply raw water pressurized with a pump to a filter medium to perform filtration, thereby providing a raw water supply pipe. The idea was to make it unnecessary to limit the installation position of the filter and to secure the space above the filter medium. However, as a result of further investigation by the present inventors, when a pump is used in a filtration device equipped with a siphon-type backwash device, a large amount of raw water supplied from the pump flows in the siphon tube when the siphon is formed. It has become clear that there is a problem that the backwashing cannot be performed effectively.

In view of this, the present invention provides an efficient backwashing in a filtration device that has a simple device structure and easy operation management, using a configuration in which raw water is pumped up by a pump and passed through a filter medium and a siphon type backwashing mechanism. It aims to make it possible.

An object of the present invention is to advantageously solve the above problems, and the filtration device of the present invention is divided into a primary side region and a secondary side region by a filter medium, and filters the treated water. A filtration unit for filtering treated material to obtain treated water, a pump for delivering the treated water to the primary region, a treated water pipe connecting the discharge port of the pump and the primary region, and a vertical direction Is located above the filtration unit, and is treated with the treatment medium and stored in the treated water storage tank. An outlet, a treated water pipe connecting the treated water storage tank and the secondary region below the treated water outlet, and one end connected to the treated water pipe between the pump and the filtration unit The other end is below the vertical position of the treated water outlet A siphon pipe that is positioned and raised up to a position that is vertically higher than the position of the treated water outlet between the one end and the other end by a predetermined height, and a control that controls driving and stopping of the pump The filter medium can be backwashed using the treated water by forming a siphon through the siphon tube, and the backwashing of the filter medium is started by forming the siphon through the siphon tube. Further comprising backwashing start detecting means for detecting and backwashing end detecting means for detecting end timing of backwashing, and the control unit stops the pump based on a detection result of the backwashing start detecting means, The pump is driven again based on the detection result of the backwashing end detection means. In this way, in the device structure in which the raw water is pumped by the pump and the filter medium is passed and the siphon type backwash mechanism is used in combination, the pump is stopped based on the detection result of the backwash start detection means, and the backwash is performed. By driving the pump again based on the detection result of the end detection means, efficient backwashing can be realized in a filtration device with a simple device structure and easy operation management.

Here, in the filtration device of the present invention, it is preferable that the backwashing start detecting means and the backwashing end detecting means are flow switches arranged on the other end side with respect to the upper end position in the vertical direction of the siphon tube. With such a configuration, it is possible to reliably detect the formation and destruction of the siphon using the presence or absence of the flow of water in the siphon tube. Therefore, the pump can be reliably stopped at the start of backwashing, and the filtration can be resumed by reliably driving the pump after completion of backwashing.

In the filtration device of the present invention, it is preferable that the filtration unit has an air vent pipe having one end connected to the primary side region and an air vent valve provided in the air vent pipe. With such a configuration, even when water in the filtration unit is discharged during backwashing due to the formation of siphons, it is possible to smoothly resume filtration after the end of backwashing.

In the filtration device of the present invention, it is preferable that the pump has an output adjusting means. By setting it as such a structure, when restarting filtration after backwashing, the output of a pump can be raised gradually and it can avoid that a to-be-processed water piping, a filtration part, etc. are damaged by a water hammer.

According to the present invention, an efficient backwashing is achieved in a filtration device that uses a structure in which raw water is pumped by a pump and passes through a filter medium, and a siphon type backwashing mechanism in combination with a simple device structure and easy operation management. Can be made possible.

It is a figure which shows schematic structure of the typical filtration apparatus according to this invention. (A)-(G) are the figures explaining the driving | running state of the filtration apparatus shown in FIG.

Hereinafter, the filtration device of the present invention is explained in detail based on a drawing.
<Filtration device>
A filtration device 100 shown in FIG. 1 includes a first pump (P1) 10, a filtration unit 20, a treated water storage tank 30, and a siphon tube 40. The filtration device 100 filters raw water (treated water) pumped from a water source 500 such as a river, a well, or a lake through the first pump 10 in the filtration unit 20, and treats the obtained treated water (purified water) with treated water. Store in the storage tank 30. The raw water is not limited to rivers, wells, and lakes, but can be pumped from a water source from which treated water that can be purified by filtration is obtained.

The first pump 10 sends the water to be treated to the primary side region of the filtration unit 20. The filtration unit 20 is divided into a primary side region and a secondary side region by a filter medium, and the water to be treated introduced from the primary side region flows into the secondary side region through the filter medium and is filtered. It functions to obtain treated water. As the filter medium, a known filter medium such as a filter membrane can be used. As the filtration membrane, for example, a ceramic membrane can be used. The ceramic membrane has advantages such as high strength, high reliability, high operational stability, and long life.

The treated water storage tank 30 has a position in the vertical direction above the filtration unit 20, and stores treated water that has been filtered by the filter medium and has flowed out of the secondary region. Furthermore, the treated water storage tank 30 has a treated water outlet 31, and when the treated water storage tank 30 stores a certain level or more of treated water and the water level reaches the treated water outlet 31, the treated water flows into the treated water outlet. 31 flows out. The position in the vertical direction of the treated water outlet 31 can be arbitrarily determined, and a position that can sufficiently secure the amount of treated water used as backwash water when backwashing the filter medium described in detail later. can do.

Furthermore, the filtration device 100 includes a water intake pipe 51, a treated water pipe 52, a treated water pipe 53, and a filtered water pipe 54. One end of the water intake pipe 51 is arranged so that the water to be treated can be taken from the water source 500, for example, in the water source 500. The other end of the intake pipe 51 is connected to the suction port of the first pump 10. The treated water pipe 52 connects the primary side region of the filtration unit 20 and the discharge port of the first pump 10. The treated water pipe 53 connects the treated water storage tank 30 and the secondary region of the filtration unit 20 below the treated water outlet 31. That is, the vertical position of the connecting portion between the treated water pipe 53 and the treated water storage tank 30 is lower than the treated water outlet 31. One end of the filtrate water pipe 54 is connected to the treated water outlet 31.

Here, the filtration apparatus 100 can also include a flocculant supply means that is connected to the water intake pipe 51 and adds a flocculant to the water to be treated in the water intake pipe 51. The flocculant supply means may be constituted by a flocculant supply tank 81, a flocculant supply pipe 82, a pump (P), and a valve. If a flocculant is added with respect to to-be-processed water, the filtration in the filtration part 20 can be performed efficiently.

Moreover, the water pipe 52 to be treated may include a line mixer 521. The line mixer 521 is disposed between the connection portion between the siphon pipe 40 and the water pipe 52 to be treated and the discharge port of the first pump 10 and functions to mix the fluid passing through the inside. If the line mixer 521 is provided, the flocculant supplied using the flocculant supply means and the water to be treated can be mixed well.

Furthermore, the filtration device 100 may have a flow rate adjustment pipe 57 for adjusting the flow rate of the water to be treated supplied to the filtration unit 20. One end of the flow rate adjusting pipe 57 is connected to the treated water pipe 52 and the other end is connected to the water intake pipe 51. In the filtration apparatus 100, the flow rate of the water to be treated supplied from the first pump 10 to the filtration unit 20 is adjusted by adjusting the amount of the water to be treated flowing into the flow rate adjusting pipe 57. The flow rate adjusting pipe 57 has a valve (not shown), and the amount of water to be treated flowing into the flow rate adjusting pipe 57 can be changed by variously adjusting the opening degree of the valve.

Here, the to-be-treated water pipe 52 may be provided with a backflow prevention valve (not shown) for preventing the backflow of the to-be-treated water during backwashing of the filter medium, which will be described in detail later. The backflow prevention valve can be disposed between the discharge port of the first pump 10 and the connection portion between the treated water pipe 52 and the siphon pipe 40. In the case where the above-described flow rate adjustment pipe 57 is provided, the backflow prevention valve includes a connection part between the flow rate adjustment pipe 57 and the treated water pipe 52 and a connection part between the treated water pipe 52 and the siphon pipe 40. Place between.

In addition, when using the filtered water filtered with the filtration apparatus 100 for drinking etc., the treated water piping 53 may have a disinfectant supply means. The disinfectant is, for example, a chlorine compound. In this case, the disinfectant supply means may be constituted by a disinfectant supply tank 61, a disinfectant supply pipe 62, a pump (P), and a valve.

One end of the siphon tube 40 is connected to the treated water pipe 52 between the discharge port of the first pump 10 and the filtration unit 20, and the other end is positioned below the vertical position of the treated water outlet 31. The siphon tube 40 is raised between one end and the other end to a position that is higher than the position of the treated water outlet 31 by a predetermined height in the vertical direction.

Therefore, in this filtration device 100, when there is no pressure loss in the filtration unit 20, that is, when there is no pressure difference (differential pressure) before and after filtration by the filter medium, the water level in the siphon tube 40 and the filter medium are two. The water level of the treated water on the secondary region side becomes equal. On the other hand, when the filtration membrane is gradually clogged during filtration due to suspended substances and colloidal substances contained in the water to be treated and a differential pressure is generated, the water level in the siphon tube 40 is higher than the water level of the treated water. Also increases by the differential pressure. That is, the water level in the siphon tube 40 gradually rises as the differential pressure increases. Then, the water to be treated in the siphon tube 40 overflows to the other end side beyond the vertical upper end position of the siphon tube 40 (also referred to as the top of the siphon tube 40 or the highest vertical position of the siphon tube 40). When the siphon tube 40 is filled with water between one end and the other end of the tube 40, the secondary region side (for example, the treated water storage tank 30) with respect to the filter medium and the other end of the siphon tube 40 In between, a siphon is formed through the siphon tube 40. Specifically, the water flow that passes through the treated water storage tank 30, the treated water pipe 53, the filtration unit 20, and the treated water pipe 52 flows into the siphon pipe 40, and the vertical upper end position of the siphon pipe 40 is set without interruption. And flows out of the siphon tube 40. Thereby, the treated water stored in the treated water storage tank 30 flows back to the other end of the siphon tube 40 through the filtration unit 20 and backwashes the filter medium. Thus, in the filtration apparatus 100, the clogging substance clogged in the filtration membrane can be removed, and the filtration performance of the filtration membrane can be recovered. Note that the other end of the siphon tube 40 may be connected to a discharge pipe 55 for discharging backwash water.

Here, the height at which the siphon tube 40 is raised is, for example, determined in consideration of the relationship between the filtration performance and the differential pressure, and is a height corresponding to the magnitude of the differential pressure at which backwashing is started. What is necessary is just to be higher than the height of the treated water outflow port 31 of the water storage tank 30.
The vertical position of the other end of the siphon tube 40 defines the amount of backwash water (backwash water amount) that flows through the filtration unit 20 during backwashing and the pressure that drives backwashing (backwash drive pressure). Therefore, in principle, the vertical position of the other end of the siphon tube 40 is lower than the water level in the treated water storage tank 30, and a position where a minimum backwash water amount and backwash drive pressure can be secured. is there. For example, when using the filtration part 20 comprised using the filtration membrane, it is practically preferable that the amount of backwash water is 0.5 liter or more per unit membrane area. Furthermore, since it is preferable that the backwash driving pressure is large, it is preferable that the difference between the water level in the treated water storage tank 30 and the vertical position of the other end of the siphon tube 40 is large. Therefore, the vertical position of the other end of the siphon tube 40 is preferably lower than the treated water storage tank 30, more preferably lower than the filtration unit 20, and the lower part of the filtration device 100, In particular, it is preferable to arrange the other end of the siphon tube 40 at the lowermost part in the vertical direction. This is because a sufficient amount of backwash water and backwash drive pressure can be secured. In the illustrated example, the other end of the siphon tube 40 is located below the filtering unit 20. Therefore, when the siphon is formed, all the water in the filtering unit 20 flows out unless the siphon is artificially destroyed using a siphon breaker or the like. Incidentally, it is not essential that all the water in the filtration unit 20 has flowed out at the end of the backwashing, and “backwashing” in the present application means that the treated water flows from the secondary region to the primary region in the filtration unit 20. Refers to backflow.

Note that the siphon tube 40 has a structure that prevents the flow of water flowing in the siphon tube 40 from being interrupted when the water that has risen in the siphon tube 40 flows through the vicinity of the upper end position in the vertical direction of the siphon tube 40 to the other end side. It has become. For example, the siphon tube 40 has a small diameter in the vicinity of the upper end position in the vertical direction of the siphon tube 40. The backwash flow rate is determined by the backwash driving pressure, the pressure loss in the siphon tube 40 during backwashing, and the degree of filtration membrane blockage of the filtration unit 20. For this reason, from the viewpoint of ensuring the backwash flow rate, the inner diameter of the siphon tube is preferably an inner diameter that can minimize the pressure loss in the siphon tube 40 during backwashing.

In addition, as mentioned above, between the discharge port of the 1st pump 10, and the connection part of the to-be-processed water piping 52 and the siphon pipe 40, more specifically, the flow volume adjustment pipe 57 and the to-be-processed water piping 52 are used. In the case where a backflow prevention valve is provided between the connection portion between the water supply pipe 52 and the siphon pipe 40, the backwash water does not flow into the water source 500 side. It is possible to make it difficult to interrupt the water flow in the siphon tube during backwashing. Alternatively, when the backflow prevention valve is not provided and the diameters of the treated water pipe 52 and the intake pipe 51 are designed larger than the siphon pipe 40, the treated water in the siphon pipe 40 exceeds the top of the siphon pipe 40. The backwashing is started by flowing over to the other end side, and after the backwashing starts, the backwashing is completed by allowing the backwash water to flow mainly to the water source 500 side through the treated water pipe 52 and the intake pipe 51. You can also.

Furthermore, the filtration device 100 includes a control unit 70 that controls the driving and stopping of the first pump 10, backwashing start detection means that detects the start of backwashing of the filter medium due to formation of the siphon through the siphon tube 40, and reverse Back washing end detection means for detecting the washing end timing is provided.

The control part 70 stops the 1st pump 10 based on the detection result (namely, detection of the backwashing start by siphon formation) of the backwashing start detection means. The backwashing start detecting means detects the formation of the siphon through the siphon tube 40, and the control unit 70 stops the first pump 10, so that the first pump 10 delivers the water to be treated during backwashing. The backwashing can be carried out at a sufficient backwashing flow rate so as not to hinder backwashing.
The controller 70 arbitrarily controls the driving and stopping of the pump of the flocculant supply unit and the pump of the disinfectant supply unit in conjunction with the first pump 10.
Moreover, the control part 70 drives the 1st pump 10 again based on the detection result (namely, detection of the end time of backwashing) of the backwashing end detection means. Filtration can be restarted by detecting the end timing of backwashing by the backwashing end detection means and driving the first pump 10 after the backwashing is completed.

Here, as the backwash start detection means and the backwash end detection means, the other end side of the siphon tube 40 in the vertical direction upper end position (in the illustrated example, from the vertical position of the treated water outlet 31 of the treated water storage tank 30). Also, a flow switch 41 arranged on the lower side can be used. The flow switch 41 is a switch that can detect the presence or absence of a water flow having a certain range of flow velocity and flow rate.
When the siphon is formed, water continuously flows to the other end side from the upper end position in the vertical direction of the siphon tube 40. When the siphon is broken, the flow of water from the upper end position in the vertical direction of the siphon tube 40 to the other end side stops. Therefore, if the flow switch 41 disposed on the other end side of the siphon tube 40 in the vertical direction is used, it is possible to reliably detect the formation and destruction of the siphon, that is, the start and end of backwashing. Note that the flow velocity and flow rate detection thresholds in the flow switch 41 can be set as appropriate so that the siphon can be reliably detected via the siphon tube 40.

When the flow switch 41 is used as the backwashing end detecting means, the control unit 70 detects that the backwashing end detecting means constituted by the flow switch 41 does not have a flow rate and flow rate within a certain range (that is, reverse It is possible to control the first pump 10 to be driven after a predetermined time has elapsed after detecting the end timing of washing. Here, the predetermined time is, for example, 30 seconds. By configuring the control unit 70 in this way, it is possible to ensure the end of backwashing and to efficiently resume filtration.

In addition, in the filtration apparatus of this invention, you may use the level switch attached to the treated water storage tank 30 other than a flow switch as a backwash start detection means and a backwash completion detection means. Specifically, when the siphon is formed, the water level of the treated water in the treated water storage tank 30 is decreased, and therefore the backwashing by the siphon formation is started by detecting the decrease in the water level in the treated water storage tank 30. It may be detected. Further, the timing at which the water level in the treated water storage tank 30 decreases to a predetermined water level, or the timing at which the decrease in the water level in the treated water storage tank 30 stops may be detected as the backwash end timing. Here, when the backwashing is finished at the timing when the water level in the treated water storage tank 30 decreases to a predetermined water level, a siphon breaker (not shown) is provided in the siphon tube 40 and the treated water storage tank 30 Backwashing can be terminated by activating the siphon breaker when the water level reaches a predetermined water level.

Here, when the vertical position of the other end of the siphon tube 40 is below the filtering unit 20, the primary side region and the secondary side region of the filtering unit 20 are filled with air after the backwashing is completed. Moreover, the filter medium in the filtration unit 20 is moist. For this reason, even if the first pump 10 is re-driven after the backwashing is finished and the water to be treated is sent out, the primary side region of the filtration unit 20 and the water in the water pipe 52 to be treated are difficult to escape through the filter medium. It takes time for the treated water to pass through the filter medium, and measures such as increasing the pump pressure of the first pump 10 are required to allow the treated water to pass through the filter medium quickly. For this reason, there exists a possibility that filtration cannot be restarted efficiently. Therefore, the filtration unit 20 preferably includes an air vent pipe 56 having one end connected to the primary side region, and an air vent valve 561 provided in the air vent pipe 56. The other end of the air vent pipe 56 is connected to a discharge pipe 55 to which, for example, a siphon pipe is connected. In this way, by providing the air vent pipe 56 and the air vent valve 561, when the filtration is resumed, the air vent valve 561 is opened to feed the water to be treated to the primary side area while venting the air in the filtration device 100, and the primary side area is covered. Filtration can be efficiently restarted by closing the air vent valve 561 after replacement with treated water. Note that the operation of the air vent valve 561 can be controlled by the control unit 70. It is of course possible to configure the air vent pipe 56 as an air vent.

In addition, when the vertical position of the other end of the siphon tube 40 is below the filtration unit 20 or below the treated water pipe 52, after the backwashing is finished, the filtration unit 20 and the treated water are treated. The inside of the pipe 52 is filled with air. Therefore, it is preferable that the 1st pump 10 has an output adjustment means (not shown) comprised, for example with an inverter. Thereby, when resuming filtration after backwashing, it is possible to gradually increase the discharge pressure of the pump and avoid damage to the filtration device due to the water hammer.

<Operation of filtration device>
The filtration device 100 shown in FIG. 1 operates in an operation state as shown in FIGS. 2 (A) to (G). 2A to 2G, for the sake of clarity, the first pump 10, the treated water pipe 52, the filtration unit 20, the treated water pipe 53, the treated water storage tank 30, and the treated water outlet in the filtration device 100 are shown. 31, only the siphon tube 40 and the flow switch 41 constituting the backwashing start detecting means are illustrated, and the remaining components are not shown. Moreover, in the filtration part 20, in order to make an understanding of the change of the water level which exists in a filtration part easy, the amount of water which exists in a filtration part was illustrated. In the following description, it is assumed that the flow switch 41 constituting the backwashing start detecting means also functions as backwashing end detecting means.

FIG. 2A is a diagram illustrating a state during filtration of the filtration device 100. In this state, the water flow of the treated water sent from the first pump 10 flows into the primary side region of the filtration unit 20 through the treated water piping 52 and becomes treated water through the filter medium on the secondary side. It flows into the region and is stored in the treated water storage tank 30 through the treated water pipe 53. When the water level in the treated water storage tank 30 rises to the same level as the treated water outlet 31, the treated water flows out from the treated water outlet 31. During the filtration, a part of the water flow of the water to be treated that flows through the water pipe 52 to be treated flows into the siphon tube 40, and the water level in the siphon tube 40 gradually rises.
FIG. 2B is a diagram illustrating a state of the filtration device 100 immediately before starting backwashing. In this state, the water level in the siphon tube 40 rises to the upper end position in the vertical direction of the siphon tube 40 due to an increase in pressure loss (an increase in differential pressure) in the filtration unit 20. Thereafter, when the flow switch 41 detects a water flow having a predetermined range of flow velocity and flow rate, the control unit stops the first pump 10.

FIG. 2C is a diagram illustrating a state of the filtration device 100 immediately after the start of backwashing. In this state, the water to be treated in the siphon tube 40 overflows beyond the top of the siphon tube 40 and reaches a position lower in the vertical direction than the treated water outlet 31 of the treated water storage tank 30.
Drawing 2 (D) is a figure showing the state of filtration device 100 under backwashing. In this state, the treated water flowing out from the treated water storage tank 30 flows into the siphon tube 40 through the treated water pipe 53, the filtering unit 20, and the treated water pipe 52, and flows out from the siphon tube 40. . At this time, the first pump 10 is in a stopped state.
FIG. 2E is also a diagram showing the state of the filtration device 100 during backwashing. In this state, all of the treated water stored in the treated water storage tank 30 flows out and only exists in the filtration unit 20 at a low water level.
FIG. 2 (F) is a diagram showing the state of the filtration device 100 just before the end of backwashing. Immediately after this state, the flow switch 41, which also serves as a backwashing end detection means, detects that there is no water flow having a certain range of flow velocity and flow rate. Thereafter, after a predetermined time has elapsed, the control unit controls to drive the first pump 10 and restarts filtration.

FIG. 2 (G) is a diagram showing the state of the filtration device 100 immediately after resumption of filtration. In this state, the water flow of the treated water sent from the first pump 10 flows into the primary region of the filtration unit 20 through the treated water pipe 52. Here, as described above, the filtering unit 20 and the water pipe 52 to be treated after backwashing are filled with air, and the filtering material in the filtering unit 20 is moist, and it is difficult for air to escape through the filtering material. There is a possibility that the water to be treated cannot be efficiently filtered. For this reason, it is advantageous to provide the air vent pipe 56 and air vent valve 561 as shown in FIG. In this case, the control unit opens the air vent valve 561 after resuming the driving of the first pump 10, vents the air in an open state for a predetermined time after resuming filtration, and then closes the air vent valve 561. The predetermined time for opening the air vent valve 561 depends on the water supply speed of the first pump 10, but is, for example, 20 to 180 seconds after resumption of filtration. Incidentally, in the stage where the treated water is allowed to flow into the filtration unit 20 after resumption of filtration, the treated water is allowed to flow out from the air vent pipe 56 while leaving the air vent pipe 56 open, so that it remains on the primary side of the filtration unit 20. It is also possible to configure so as to eliminate the accumulated deposits. In this case, the air vent valve 561 can be opened for a time longer than 180 seconds.

As mentioned above, although the filtering apparatus of this invention and the operation | movement method of this filtration apparatus were demonstrated using an example, the operation | movement method of the filtration apparatus and filtration apparatus of this invention is not limited to the said example, and adds suitably. be able to.
For example, although only one filtration unit is shown in FIG. 1, it is of course possible to provide a plurality of filtration units in the filtration device. Thereby, the amount of filtered water can be increased.

The filtration device of the present invention adopts a configuration in which raw water is pumped up by a pump and the filter medium is passed through and a siphon-type backwash mechanism is used in combination, so that the device structure is simple and operation management is easy, as well as efficiency. Backwashing is possible.

10: First pump (P1)
20: Filtration unit 30: Treated water storage tank 31: Treated water outlet 40: Siphon pipe 41: Flow switch 51: Intake pipe 52: Treated water pipe 53: Treated water pipe 54: Filtered water pipe 55: Drain pipe 56: Air vent pipe 57: Flow rate adjusting pipe 61: Disinfectant supply tank 62: Disinfectant supply pipe 70: Control unit 81: Flocculant supply tank 82: Flocculant supply pipe 100: Filtration device 521: Line mixer 561: Air vent valve

Claims

The inside is divided into a primary side region and a secondary side region by the filtering material, and a filtration unit that obtains treated water by filtering the treated water with the filtering material,
A pump that delivers the treated water to the primary region;
A treated water pipe connecting the discharge port of the pump and the primary side region;
A treated water storage tank that stores the treated water that is filtered by the filter medium and flows out from the secondary side region, the vertical position being above the filtration unit;
A treated water outlet provided in the treated water storage tank;
A treated water pipe connecting the treated water storage tank and the secondary region below the treated water outlet;
One end is connected to the treated water pipe between the pump and the filtration unit, the other end is located below the vertical position of the treated water outlet, and the one end and the other end A siphon tube raised to a position that is higher than the position of the treated water outlet by a predetermined height in the vertical direction;
A control unit for controlling driving and stopping of the pump;
With
The filter medium can be backwashed using the treated water by forming a siphon through the siphon tube,
A backwash start detecting means for detecting the backwash start of the filter medium due to the formation of the siphon through the siphon tube, and a backwash end detecting means for detecting the backwash end timing;
The said control part stops the said pump based on the detection result of the said backwash start detection means, and drives the said pump again based on the detection result of the said backwash completion detection means, The filtration apparatus characterized by the above-mentioned.
2. The filtration device according to claim 1, wherein the backwashing start detection unit and the backwashing end detection unit are a flow switch arranged on the other end side with respect to a vertical upper end position of the siphon tube. .
The filtration unit is
An air vent pipe having one end connected to the primary region;
It has an air vent valve provided in the said air vent piping, The filtration apparatus of Claim 1 or 2 characterized by the above-mentioned.
The filtration device according to any one of claims 1 to 3, wherein the pump has output adjusting means.