CN116348187A

CN116348187A - Filtration system and filtration method

Info

Publication number: CN116348187A
Application number: CN202180067917.1A
Authority: CN
Inventors: 西村章; 田中裕光
Original assignee: Stream Turbine Engineering Co ltd
Current assignee: Stream Turbine Engineering Co ltd
Priority date: 2020-12-28
Filing date: 2021-11-08
Publication date: 2023-06-27
Also published as: WO2022145132A1; JP7132645B2; JP2022104288A

Abstract

Provided are a filtering device and a filtering method, wherein maintenance of a filter is easy and running cost can be suppressed. The filter system (1) of the present invention comprises: a filtration vessel (11) having a supply port (11A) for the liquid to be treated (A) and a discharge port (11B) for the liquid to be treated (B); a filter (12) provided inside the filter container (11), the outer surface of which is a filter surface, and the inside of which is a passage (12 r) for the treatment liquid; a cleaning powder supply unit for supplying cleaning powder (F) for cleaning the filter (12) to the filter container (11); and a vibrator (73) that vibrates at least one of the filter (12) and the cleaning powder (F) in a state in which the cleaning powder (F) is accumulated outside the filter, and rubs the filter (12) against the cleaning powder (F).

Description

Filtration system and filtration method

Technical Field

The present invention relates to a filtration system and a filtration method for obtaining drinking water, pure water, or the like.

Background

Raw water obtained from sea, lake, river, etc. contains a large amount of clay minerals, organic compounds that enter between layers of the clay minerals, hard particles such as fragments of sand or rock, soft particles such as fragments of plants, microparticles such as microplastic, etc. Therefore, if such raw water is directly introduced into a filtration apparatus including an RO membrane (hereinafter referred to as "reverse osmosis membrane") or an ion exchange resin layer, there are drawbacks such as easy clogging of the RO membrane or rapid ion exchange between ions in the raw water and the ion exchange resin, and as a result, the RO membrane, the ion exchange resin layer, and the like must be frequently replaced. In particular, in a small-sized filter device, a disposable type wound filter or pleated filter is often used, but the filter needs to be replaced frequently because the flow of water from the raw water to the clogging is fast. In addition, when the turbidity of raw water is high, the filter replacement speed tends to be high.

As a prior art related to the present invention, there is a technology described in patent document 1 below. In the filtration method described in patent document 1, a release layer is first formed on the outer surface of a filter, and then the liquid to be treated is filtered to form an adhesion layer on the release layer. Then, at the stage of forming the adhesion layer, the adhesion layer is peeled off by setting the supply pressure of the liquid to be treated to a predetermined cleaning pressure. In this cleaning, the powder particles are mixed into the liquid to be treated, thereby effectively peeling the liquid. Patent document 1 also discloses a filtration device for performing such filtration.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2019-58688

Disclosure of Invention

Problems to be solved by the invention

As described above, when raw water is directly introduced into the filtration apparatus, there is a problem in that it is difficult to continuously operate the filtration apparatus. In addition, even before the operation of the filtration apparatus is stopped, for example, if the filtration membrane of the filtration apparatus starts to be clogged, there is a problem that the amount of water produced becomes small. In addition, there are the following problems: the running cost is high because the cost of the filter (consumable) mounted on the filtering device is high alone; and since the replacement work of the filter takes time, the operation stop time of the filter device becomes long, or the replacement work requires manpower.

In the filtration method and the filtration apparatus described in patent document 1, it is necessary to increase the supply pressure (cleaning pressure) of the liquid to be treated in order to peel off the adhesion layer, or to continuously rotate the cylindrical filter during cleaning, and the running cost tends to increase. Further, since a rotary unit or the like for installing a filter is necessary, the filter device tends to be large as a whole, and is not suitable for being mounted on a ship or the like or used in a home, for example.

Accordingly, a main object of the present invention is to provide a filtration system and a filtration method that can easily maintain a filter and can reduce the running cost.

Means for solving the problems

In order to solve the above problems, the following modes can be adopted.

(mode 1)

A filtration system characterized in that it has:

a filter container having a supply port for the liquid to be treated and a discharge port for the liquid to be treated;

a filter provided in the filter container, the filter having a filter surface on an outer surface thereof and a treatment liquid passage in the filter container;

a cleaning powder supply unit that supplies cleaning powder for cleaning the filter to the filter container; and

And a vibrator that vibrates at least one of the filter and the cleaning powder and rubs the filter against the cleaning powder and the cleaning powder in a state where the cleaning powder and the cleaning powder exist in the filter container.

A filtration system, comprising:

and a vibrator that vibrates at least one of the filter and the cleaning powder and rubs the filter and the cleaning powder in a state where the cleaning powder volume is outside the filter.

(effects of action)

As the liquid to be treated is filtered by the filter, a cake is formed on the outer surface of the filter, and the thickness of the cake becomes thicker. Since such a cake hinders filtration of the liquid to be treated, it is necessary to peel the cake from the filter at a stage at which the cake reaches a predetermined size and discharge the peeled cake from the filtration vessel.

In order to peel off a cake from a filter, a filter device according to the present embodiment includes: a cleaning powder supply unit for supplying cleaning powder to the filter container; and a vibrator that vibrates at least one of the filter and the cleaning powder in a state where the cleaning powder volume is present outside the filter, and rubs the filter against the cleaning powder.

When at least one of the filter and the cleaning powder is vibrated in a state where the cleaning powder volume is stored outside the filter, the filter rubs against the cleaning powder, and thus the cake adhering to the outer surface of the filter is abraded by the cleaning powder.

In this way, the filter device of the present embodiment does not use a disposable type wound filter or a disposable type pleated filter, and therefore, the filter replacement work is not required, and the cleaning and regeneration of the filter can be automated.

Further, since the liquid to be treated mixed with the powder or granular material is not sprayed onto the surface of the filter as in patent document 1, it is not necessary to supply the liquid to be treated to the filter vessel at a high pressure, and a small-sized low-pressure pump for the liquid to be treated can be used. Further, since the liquid to be treated mixed with the powder or granular material is not sprayed onto the surface of the filter as in patent document 1, a rotation unit for rotating the filter during cleaning of the filter is not required, and not only the power required for rotation of the filter is not required, but also the entire filter device can be miniaturized and reduced in weight.

As described above, by miniaturizing and reducing the power of the filter device, for example, it is possible to easily install in a ship or transport to a difficult camp, and it is possible to generate domestic water (including drinking water) and the like required in the future while suppressing the running cost.

In addition, no special knowledge is required to operate the filtering device, and any person can easily use the filtering device, so that convenience is high. Further, since the filter does not need to be replaced as described above, the filter can be operated continuously without a person, and thus domestic water or the like can be generated even during sleeping (at night or the like) of a person, and the filter is particularly useful in places requiring a large amount of domestic water such as a difficult camp.

In the present embodiment, an RO membrane filtration device (hereinafter referred to as "reverse osmosis membrane filtration device") may be disposed in series in the rear stage of the filtration device. By disposing an RO membrane filtration device or the like in the latter stage, water (mainly drinking water) having less impurities can be obtained. In addition, if a large amount of impurities are removed by the filtration apparatus of the present embodiment before the liquid to be treated is supplied to the RO membrane filtration apparatus or the like, the frequency of clogging of the filter of the RO membrane filtration apparatus or the like can be reduced, and the number of times of interrupting the filtration process can be reduced. Specifically, in the case where an RO membrane filtration apparatus or the like is arranged in series in the rear stage of the filtration apparatus of the present embodiment, it is preferable that the turbidity of the liquid to be treated in the filtration apparatus of the present embodiment is about 0.1mg/L or less.

(mode 2)

A filtration system characterized in that it has:

a cleaning container for cleaning the filter;

a moving unit that moves the filter from the filter container to the cleaning container;

a cleaning powder supply unit that supplies cleaning powder for cleaning the filter to the cleaning container; and

and a vibrator that vibrates at least one of the filter and the cleaning powder and causes the filter to rub against the cleaning powder and the cleaning powder in a state in which the filter is moved to the cleaning container and the cleaning powder volume is stored outside the filter.

(effects of action)

Unlike the 1 st aspect, the 2 nd aspect is characterized in that the filter is cleaned inside the cleaning vessel. The provision of the cleaning vessel separately from the filtration vessel has a disadvantage of consuming the equipment cost, but the time required for cleaning and regenerating the filter can be shortened, and thus the time required for stopping the filtration process of the liquid to be treated can be shortened.

For example, in the case of a type of filter apparatus in which the filter is cleaned inside the filter vessel as in the 1 st aspect, after the filtration of the liquid to be treated is temporarily stopped, (1) the cleaning powder is supplied to the filter vessel and the cleaning powder is stored inside the filter vessel; (2) Then, at least one of the filter and the cleaning powder is vibrated to remove a cake formed on the outer surface of the filter; (3) Thereafter, the cleaning powder and the peeled cake are discharged from the inside of the filter vessel. After the end of the discharge of the cleaning powder and the cake, the filtration of the liquid to be treated can be restarted.

In contrast, if the cleaning vessel is provided separately from the filter vessel as in the present embodiment, the cleaning powder particles can be stored in the cleaning vessel. Therefore, when regenerating the filter, the filter is taken out from the filter container and moved to the cleaning container, and the filter is placed in the cleaning powder stored in the cleaning container in advance, whereby the time required for the above (1) can be omitted.

Thereafter, at least one of the filter and the cleaning powder is vibrated, and the process of peeling off the cake formed on the outer surface of the filter is the same, but the time required for the following step (3) may be omitted. That is, in the filtering apparatus according to the present embodiment, the regenerated filter can be immediately moved again to the filtering container, and the filtering process of the liquid to be treated can be quickly restarted. The discharge of the cleaning powder and the cake from the cleaning vessel may be performed after the filter is moved from the cleaning vessel to the filtering vessel.

As described above, this embodiment has the following advantages, unlike embodiment 1: in comparison with the embodiment 1, the restart of the filtration of the liquid to be treated can be advanced by the time required for the above (1) and (3).

(mode 3)

The filtration system according to the above 1 or 2, wherein the filter is a pleated filter having a flat filter medium which is corrugated to form a plurality of pleats and is formed in a cylindrical shape.

(effects of action)

By using the pleated filter, the throughput of the liquid to be treated can be greatly increased, and the entire filter device can be miniaturized.

In addition, when a pleated filter is used, there is a disadvantage in that it is difficult to peel off a cake generated at a valley portion between pleats. In this embodiment, the following is adopted: at least one of the pleated filter and the cleaning powder is vibrated in a state where the cleaning powder volume is stored in the filter container, and the pleated filter is rubbed against the cleaning powder. With such a configuration, the cleaning powder can be reliably inserted into the valley portions between the pleats of the pleated filter, and the cleaning powder can be rubbed against the pleated filter by vibration, whereby the cake formed on the outer surface of the valley portions of the pleated filter can be reliably peeled off.

(mode 4)

The filtration system according to the above aspect 1 includes a discharge unit that blows pressurized gas into the filtration vessel and discharges the cleaning powder from the filtration vessel.

(effects of action)

It is necessary to discharge the cleaning powder stored in the filter vessel before the filtration process is restarted. This is because, when the cleaning powder remains in the filter container during the filtration process, the cleaning powder accumulates on the outer surface of the filter, and the filtration of the liquid to be treated is inhibited.

Therefore, it is preferable to discharge most of the cleaning powder (preferably all of the cleaning powder) from the inside of the filter vessel before restarting the filtration process. A method of discharging the cleaning powder from the lower portion of the filter vessel by the self weight of the cleaning powder may be considered, but it is difficult to discharge the cleaning powder efficiently because the cleaning powder itself is light in weight.

Therefore, in this embodiment, a configuration in which the discharge means is provided is adopted. The following constitution is adopted: the discharge means blows pressurized gas into the filter vessel, and discharges the cleaning powder from the filter vessel by the wind of the pressurized gas. By adopting such a configuration in which the purge powder is extruded by the gas, the purge powder can be rapidly discharged from the filter vessel, and thus the restart of the filtration process can be accelerated. In addition, even when the filter has a complicated structure such as a pleated filter, if pressurized gas is used, the cleaning powder particles adhering to the pleats of the pleated filter and the valley portions between the pleats can be swiftly scraped off.

It is also conceivable to discharge the cleaning powder from the filter vessel by flowing a liquid (e.g., water) into the filter vessel. However, when the liquid contains a large amount of impurities, there is a possibility that a large amount of impurities remain in the interior of the filter vessel and on the outer surface of the filter. Therefore, a liquid having a small impurity content has to be used, and time, power, cost, and the like are required to generate such a liquid, so that the efficiency is poor. Further, since the liquid has adhesion, the liquid containing the cleaning powder is liable to remain in the filter container and on the outer surface of the filter. In view of the above, the pressurized gas according to this embodiment is preferably used to discharge the cleaning powder from the filter vessel.

(mode 5)

The filtration system according to the above aspect 1 is provided with a partition wall that covers an upper end portion or a lower end portion of the filter and that separates a space in which the liquid to be treated is present from a space in which the liquid to be treated is present, and the partition wall is an elastic partition wall.

(effects of action)

By providing a partition wall that covers the upper end portion or the lower end portion of the filter and that separates the space in which the liquid to be treated is present from the space in which the liquid to be treated is present, the liquid to be treated can be prevented from moving to the filtrate passage without passing through the filtration membrane. In addition, by making the partition wall elastic, the vibration force of the vibrator can be concentrated on the filter, and the vibration of the vibrator can be prevented from being transmitted to the filter container.

(mode 6)

The filtration system according to the above aspect 1 is provided with a partition wall that covers an upper end portion or a lower end portion of the filter and that separates a space in which the liquid to be treated is present from a space in which the liquid to be treated is present, and a storage chamber that stores the liquid to be treated is provided in the filtration vessel on the opposite side of the filter from the partition wall.

(effects of action)

In this embodiment, a storage chamber for storing the treatment liquid is provided in the filter container. In order to discharge the cleaning powder from the interior of the filter vessel, a treatment liquid provided in the storage chamber is used, and thus the cleaning powder is less likely to remain in the interior of the filter vessel.

(mode 7)

A filtration method for filtering a liquid to be treated by using a filtration system comprising:

a filtration vessel having a supply port for the liquid to be treated and a discharge port for the liquid to be treated; and

a filter provided in the filter container, having a filter surface on an outer surface thereof and a passage for the treatment liquid therein,

the filtration method is characterized in that,

comprises a cleaning step of removing a cake formed on the outer surface of the filter by filtering the liquid to be treated,

In the above-mentioned washing step, the washing step,

supplying a cleaning powder to the filter vessel, storing the cleaning powder volume outside the filter,

at least one of the filter and the cleaning powder is vibrated, and the filter cake formed on the outer surface of the filter is removed by the cleaning powder.

(effects of action)

The same operation and effect as those of the mode 1 are achieved.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a filtration system and a filtration method which can easily perform maintenance of a filter and can suppress running costs.

Drawings

Fig. 1 is a view showing the overall configuration of the apparatus of the filtration system according to embodiment 1 of the present invention.

Fig. 2 is an enlarged view of the filter device of fig. 1.

Fig. 3 is a top view of the filter of fig. 1.

Fig. 4 is an enlarged view of a portion Y of fig. 3.

Fig. 5 is an enlarged view of the wrinkled portion of fig. 4. (5A) The state before filtering is shown, and (5B) the state during filtering is shown.

Fig. 6 is a view in the A-A direction of fig. 2. The upper filter membrane sealing portion is marked with oblique lines. For reference, positions of the filtrate discharge pipe and the supply pipe of the discharge compressed gas are indicated by dotted lines.

Fig. 7 is a table showing the opening period of the valve, the operation period of the gas compressor, and the operation period of the vibrator. The 2 nd cleaning step and the post-treatment step are the same as the 1 st cleaning step and the 1 st post-treatment step. The filtration step, the washing step, and the post-treatment step after the 3 rd step are the same as the 2 nd filtration step, the washing step, and the post-treatment step.

Fig. 8 is a filter device of a filter system according to embodiment 2 of the present invention.

Fig. 9 is a filter device of a filter system according to embodiment 3 of the present invention. The state in which the filter is located inside the filter container is shown, and the state in which the filter is mounted inside the cleaning container is shown by a broken line.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described. The following description and drawings represent only one embodiment of the present invention, and the present invention should not be construed as being limited to this embodiment.

(liquid to be treated A)

Examples of the liquid to be treated a filtered by the filtering device 10 of the present invention include water from a river or a lake, seawater, groundwater, water from a flush, and water discharged from a factory.

(filtration device 10)

The filtration apparatus 10 according to the embodiment is a full-volume filtration (dead-end filtration) apparatus in which the treatment liquid a is filtered by the filter 12 in the closed filtration vessel 11 and the treatment liquid B (for example, filtrate, hereinafter referred to as "filtrate B") is discharged.

(filtration vessel 11)

The filter device 10 includes a filter container 11 that accommodates a filter 12. A supply port 11A of the treatment liquid a and a discharge port 11C of the cake K are provided in the lower part of the filtration vessel 11, and a discharge port 11B of the treatment liquid (filtrate) B is provided in the upper part of the filtration vessel 11. In the filter device 10 shown in fig. 2, the cake discharge port 11C serves as both the cleaning powder supply port 5A for supplying the cleaning powder 5 into the filter vessel 11 and the cleaning powder discharge port 5B for discharging the cleaning powder 5 from the filter vessel 11, but the

supply ports

11C, 5A and the discharge port 5B may be separately provided.

(cylindrical body 12 s)

The filter container 11 is provided with a tubular body 12s having a wall surface provided with a permeation hole for the filtrate B and a filtrate passage 12r formed therein. In the figure, the filter container 11 is shown as a cylindrical shape, and is disposed in the filter container 11 in a posture in which the center thereof is located along the vertical direction of the filter container 11. The shape and posture of the tubular body 12s are not particularly limited, and the shape of the tubular body 12s may be changed to any known shape such as a square tubular shape, or the posture of the tubular body 12s may be set in the filter container 11 so that the central axis of the tubular body 12s is in the horizontal direction. The illustrated tubular body 12s is formed by molding a flat plate having a transmission hole such as a punched metal into a cylindrical shape, and the space in the tubular body 12s serves as a filtrate passage 12r.

(filtration membrane 12 m)

A filtration membrane 12m is provided outside the wall surface of the tubular body 12s. As the filtering membrane 12m, a pleated filter formed by bending a flat filtering material into a zigzag shape (corrugated shape) and winding the flat filtering material around the outer peripheral surface of the tubular body 12s to form a cylindrical shape is preferably used because of its large surface area (filtering area). By using a pleated filter, the surface area of the filter is increased compared to a simple flat filter having no filter medium folded, and thus the throughput per unit time of the liquid to be treated a can be significantly improved.

The filter medium is bent into a zigzag shape as described above, whereby a plurality of pleats 2 can be formed. The pleated filter has an advantage in that the interval between adjacent pleats 2 and the wall surface of the pleat 2 gradually widens from the inside to the outside, and thus the filter cake K is easily peeled off and discharged. The length L1 between the adjacent pleats and the distal ends 2p, 2p of the pleats may be 6mm, for example, and the length L2 from the distal end 2p to the proximal end 2b of the pleats may be 100mm, for example.

The filter membrane 12m may be a single layer or multiple layers. As a material (filter medium) of the filter membrane 12m, polytetrafluoroethylene (also called "teflon" (registered trademark)), polyester, polyphenylene sulfide (PPS) resin, nylon, stainless steel, or the like can be used, for example. The membrane thickness of the filtration membrane 12m is preferably 0.3mm to 0.7mm, more preferably 0.6mm. The fiber diameter of the filter medium (hereinafter referred to as the projected area equivalent circle diameter and Heywood diameter) is preferably 0.1 μm to 3. Mu.m, more preferably 0.1. Mu.m. When a fiber having a fiber diameter smaller than 0.1 μm is used, the resistance at the time of filtration becomes large and the apparent surface area becomes narrow. When a fiber having a fiber diameter larger than 3 μm is used, suspended particles in the treatment solution A pass through gaps between fibers of the filtration membrane 12m. Therefore, it is preferable to form the filtration membrane 12m having a certain degree of mesh roughness by using a filter material having a fiber diameter of 0.1 μm to 3 μm. With such a filtration membrane 12m, suspended particles in the treatment solution a adhering to the surface of the filtration membrane 12m act as a filtration layer during filtration. The length of the filtering membrane 12m in the longitudinal direction may be 300mm to 2000mm, for example.

In the present embodiment, the surface 12f of the filtration membrane 12m is a surface facing the filtration vessel 11, and is a surface in contact with the liquid to be treated a. On the other hand, the back surface 12B of the filtration membrane 12m is a surface facing the tubular body 12s, and is a surface in contact with the filtrate B.

In addition, it is preferable to use a filtration membrane 12m having a predetermined strength or higher so as not to damage the surface 12f of the filtration membrane 12m during cleaning. For example, a tensile strength (N/5 cm) in the measuring method of JIS L-1906 can be used: 1200. and (3) transverse: 700. breaking Strength (kgf/cm) ² ) Longitudinal: 25.

The upper and lower ends of the pleats of the filtration membrane 12m are sealed, respectively, to prevent the treatment target liquid a from flowing into the filtrate passage 2r without passing through the filtration membrane 12 m. The sealing portion at the upper end portion of the filter membrane 12m is referred to as an upper filter membrane sealing portion 14a, and the sealing portion at the lower end portion of the filter membrane 12m is referred to as a lower filter membrane sealing portion 14b. In the upper side of the filtration membrane 12m, the portion overlapping the filtrate passage 12r is preferably not sealed. This is to prevent the filtrate B from being unable to move from the filtrate passage 12r to the liquid reservoir 51.

The method for fixing the filtration membrane 12m in the filtration vessel 11 is not particularly limited. In the embodiment shown in fig. 2, the filtration membrane 12m is suspended by a plurality of support rods 86 extending downward from the upper wall of the filtration vessel 11. The plurality of support rods 86 are arranged in a circular shape at predetermined intervals in the circumferential direction in the cross section of the filtration membrane 12m, but are not necessarily arranged in a circular shape. As another fixing method, for example, the filter container 11 may be fixed to a side wall or the like.

As shown in fig. 2, the distance N from the side inner wall of the filtration vessel 11 to the filtration membrane 12m is preferably as short as possible. That is, the side gap 50s is preferably reduced as much as possible. This is because the shorter the distance N is, the more easily a large amount of the cleaning powder particles F are deposited around the filtration membrane 12 m. Specifically, the distance N from the side inner wall of the filter vessel 11 to the front end 2p of the pleat 2 of the filter membrane 12m is preferably set to about 3mm to 15mm, and preferably about 4 to 7 mm. If the distance N is shorter than 3mm, the filter membrane 12m may collide with the inner wall of the filter vessel 11 and be damaged when the filter membrane 12m vibrates, and if the distance N is longer than 15mm, the volume of the side gap 50s increases, so that a large amount of the cleaning powder particles F must be supplied into the filter vessel 11 in order to deposit the cleaning powder particles F around the filter membrane 12m, and as a result, the cleaning time may be prolonged.

(partition wall 88)

A partition wall 88 is preferably provided at the upper end portion of the filtration membrane 12 m. The partition wall 88 is not particularly limited, but is preferably a partition wall that is impermeable to liquid or hardly permeable to water. More preferably elastic. For example, a silicone sponge, a fluororubber sponge, a urethane rubber sponge, or the like can be used. The partition wall 88 shown in fig. 2 is formed of an annular plate-like member having a through hole 88c formed in the central portion thereof, and the outer side wall 88b thereof is fixed to the inner wall of the filter container 11 without any gap. The size of the through hole 88c provided in the central portion of the partition wall 88 is the same as that of the filter passage 12r, but may be smaller than that of the filter passage 12r. It is not preferable to make the size of the through hole 88c of the partition wall 88 larger than the filter passage 12r. In the case where the size of the through-hole 88c of the partition wall 88 is made larger than the filter passage 12r, some kind of barrier may be provided so that the liquid to be treated a and the cleaning powder or particle F do not pass through the filter membrane 12m and do not move to the liquid storage chamber 51.

The partition wall 88 is a gasket provided to prevent the liquid to be treated a and the cleaning powder F from moving to the filtrate passage 12r and the liquid reservoir 51 without passing through the filtration membrane 12 m. In addition, by providing the partition wall 88 with elasticity, the vibration force of the vibrator 73 can be concentrated on the filter 12, and the vibration of the vibrator 73 can be prevented from being transmitted to the filter container 11. The hardness of the partition wall 88 is not particularly limited, but is preferably about 40 to 160KPa, more preferably about 60 to 90 KPa. If the pressure is less than 40KPa, the sealing by the partition wall 88 is insufficient, and the liquid a to be treated in the side gap 50s may leak out into the liquid reservoir 51 through the gap of the partition wall 88. On the other hand, if the pressure is greater than 160KPa, the vibration of the vibrator 73 is easily transmitted to the filter container 11. The hardness (compressive elastic modulus) of the partition wall 88 was measured in accordance with K6254 of JIS (japanese industrial standard).

The embodiment shown in fig. 2 is as follows: since the treatment liquid a is introduced from the lower side of the filtration vessel 11 and the treatment liquid B is discharged from the upper side of the filtration vessel 11, a partition wall 88 is provided on the upper side of the filtration membrane 12m, and the partition wall 88 covers the upper end portion of the filter 12 from the upper side. In contrast, when the treatment liquid a is introduced from the upper side of the filtration vessel 11 and the treatment liquid B is discharged from the lower side of the filtration vessel 11, it is preferable to provide the partition wall 88 on the lower side of the filtration membrane 12m, and the partition wall 88 covers the lower end portion of the filter 12 from the lower side.

(liquid storage Chamber 51)

A liquid storage chamber 51 is provided inside the filter container 11. The liquid storage chamber 11 is a chamber provided for storing the filtrate B, and is provided in the rear stage of the filter 12. When the filter 12 is cylindrical in shape and is of a type in which liquid is passed from the outside to the inside, a filtrate passage 12r is formed in the filter 12, and the liquid storage chamber 11 is provided further in the rear stage of the filtrate passage 12 r. In the embodiment shown in fig. 2 and 8, the liquid storage chamber 51 is provided above the filtrate passage 12r (the upper end of the filtrate passage 12r is the same as the upper end of the filtration membrane 12, and the lower end of the filtrate passage 12r is the same as the lower end of the filtration membrane 12) and above the partition wall 88.

In the post-treatment step described later, the advantage of providing the liquid reservoir 51 is exhibited. In the post-treatment step, the cleaning powder F needs to be discharged from the interior of the filter vessel 11, but the force of the compressed gas CA2 alone is insufficient, so the cleaning powder F tends to remain in the interior of the filter vessel 11 (

gaps

50s and 50u. Particularly around the filter membrane 12 m. The same applies hereinafter). Therefore, the storage chamber 51 is provided, and the filtrate B stored in the liquid storage chamber 51 is preferably used to discharge the cleaning powder or granule F. That is, when the compressed gas CA2 presses the filtrate B stored in the liquid storage chamber 51 and the pressed filtrate B is used to discharge the cleaning powder F, the cleaning powder F is less likely to remain in the filter container 11.

In addition, a large amount of fragments of the cake K, which fragments due to vibration, exist outside the filter membrane 12 m. A part of the cake K adheres to the filtration membrane 12m, falls down and is accumulated in the bottom of the filtration vessel 11. In the post-treatment step, it is also necessary to discharge the cake K and other impurities (substances mixed into the liquid a to be treated and not in the form of a block) from the inside of the filtration vessel 11, but the extrusion force by the compressed gas CA2 alone is insufficient at the time of this discharge. Therefore, when the filtrate B provided in the storage chamber 51 is used, these cake K and impurities are also less likely to remain in the interior of the filtration vessel 11.

In the embodiment of fig. 2 and 8, the filter 12 is provided at the lower side of the filter vessel 11, the liquid to be treated a is supplied from the lower side of the filter vessel 11, and the filtrate B is discharged from the upper side of the filter vessel 11, and therefore the liquid reservoir 51 is provided at the upper side of the filter vessel 11. In contrast, in the case of the type in which the filter 12 is provided on the upper side of the filter vessel 11, the treatment target liquid a is supplied from the upper side of the filter vessel 11, and the filtrate B is discharged from the lower side of the filter vessel 11, the liquid storage chamber 51 is preferably provided on the lower side of the filter vessel 11.

The size of the reservoir 11 can be arbitrarily determined. In the embodiment of fig. 2 and 8, the filter container 11 is divided into about 2 parts in the vertical direction, the upper half is the liquid storage chamber 51, and the filter 12 is provided in the lower half as the filtration processing space (space on the opposite side of the liquid storage chamber 51 from the partition wall 88). The ratio can be arbitrarily changed, and it is necessary to store a certain amount of the filtrate B in the liquid storage chamber 11 in order to discharge the cleaning powder or granular material F, the cake K, and the like from the filter vessel 11. If the amount B of the stored filtrate is excessive, in the embodiment shown in fig. 2 and 8, the gravity applied to the partition wall 88 and the filter 12 provided at the lower portion of the liquid storage chamber 11 increases, and there is a possibility that the gravity will be lost.

Thus, the volume of the liquid storage chamber 11 is preferably smaller than the volume of the filtration processing space. Specifically, the ratio of the volume of the liquid storage chamber 11 to the volume of the filtration treatment space is preferably 1 (the volume of the liquid storage chamber 11) to 1.2 or more (the volume of the filtration treatment space), and more preferably 1 (the volume of the liquid storage chamber 11) to 1.5 or more (the volume of the filtration treatment space).

(Filter support 29)

A support plate (filter support 29) formed by bending a honeycomb net, a metal net, or the like into a zigzag shape is preferably disposed along the pleat shape on the inner surface of the pleat 2 (so as to be in contact with the back surface 12q of the filter membrane 12 m). Fig. 5 (5A) is an enlarged cross-sectional view of the filter membrane 12m before filtration, and fig. 5 (5B) is an enlarged cross-sectional view of the filter membrane 12m during filtration. As the filter cake K is deposited on the surface 12f of the filter membrane 12m, the pleats 2 of the pleated filter are crushed, and there is a possibility that "blocking" in which the space in the pleats 2 disappears may occur, but by providing the filter support plate 29, this blocking can be prevented. In the filtration of the liquid to be treated a, the membrane thickness 2w of the filtration membrane 2 is narrower than before the filtration.

(supply of the liquid to be treated A)

As described above, in the filter apparatus 10 of fig. 2, the supply port 11A for the liquid a to be treated is provided in the bottom surface of the filter container 11, but the position may be changed to any position such as the upper portion or the side portion of the filter container 11.

The tank 7 for storing the liquid to be treated a is connected to the filter vessel 11 via a supply pipe 13, and the liquid to be treated a is sent from the tank 7 to the filter vessel 11 by the suction force of the pump 8 (liquid to be treated supply pump). It is preferable that a foreign matter removing device 9 (for example, a strainer) is provided between the storage tank 7 and the filtration vessel 11, and foreign matters such as refuse in the liquid to be treated a are removed by the foreign matter removing device 9. In the present embodiment, 1 pump 8 is provided, but if it is desired to increase the amount of the liquid a to be treated, the number of pumps may be increased to 2 or more. The following structure may be used: the tank 7 is provided with a level gauge (not shown), and when the liquid to be treated a in the tank 7 is less than a predetermined value, the liquid is replenished from the outside.

(draining of filtrate B)

As described above, the outlet 11B for discharging the filtrate B to the outside of the filter vessel 11 is provided at the upper portion of the filter vessel 11. The filtrate B moves from the upper end opening of the filtrate passage 12r to the liquid storage chamber 51 through the central opening of the partition wall 88, and is then guided to the discharge pipe 16 through the filtrate discharge pipe 15 and the discharge port 11B. As described above, in the embodiment of fig. 1, the outlet 11B for the filtrate B is provided at the upper portion of the filtration vessel 11, but may be provided at any position such as the lower portion or the side portion of the filtration vessel 11.

(cleaning powder supply Unit 80)

When filtration is performed by the filtration apparatus 10, suspended particles (mainly suspended particles other than the refractory substance E) in the liquid a to be treated are deposited on the outer surface of the adsorbent layer 47, and a cake K is formed. Specifically, as the filtration proceeds, the gap between the filter membranes 12m of the filter 12 becomes smaller by the suspended substances, and a cake K is formed outside the filter 12. As the thickness of the filter cake K becomes thicker, the filtration ability of the treatment liquid a decreases. Therefore, it is necessary to peel off the cake K at the time when the cake K reaches a predetermined thickness and discharge the cake K from the filtration device 10.

The cleaning powder F was used to peel off the cake K. In the embodiment of fig. 1, a cleaning powder supply unit 80 for supplying the cleaning powder F to the filter vessel 11 is provided. The cleaning powder supply unit 80 may be manufactured as a single component of the filter device 10, or may be manufactured as a different product from the filter device 10 and then attached to the filter device 10.

The cleaning powder supply unit 80 illustrated in fig. 1 includes: a cleaning powder storage tank 75 for storing cleaning powder F; a gas compressor 76 that generates compressed gas; a compressed gas supply pipe 77 for supplying compressed gas from the gas compressor 76 to the cleaning powder storage tank 75; and a cleaning powder supply pipe 78 for supplying the cleaning powder F from the cleaning powder storage tank 75 to the filter container 11. In the filtration system 1 of fig. 1, the cleaning powder supply pipe 78 also serves as the cleaning powder discharge pipe 79 for returning the used cleaning powder F from the filtration vessel 11 to the cleaning powder storage tank 75, but the cleaning powder supply pipe 78 and the cleaning powder discharge pipe 79 may be separately provided. The valve V2 is provided in the middle of the cleaning powder supply pipe 78 and the cleaning powder discharge pipe 79.

The cleaning powder supply unit 80 may not be a unit using compressed gas as shown in fig. 1. For example, a storage tank (not shown; a liquid for supplying the cleaning powder particles F to the filtration vessel 11) and a pump (not shown; the liquid for supplying may be stored) may be provided instead of the gas compressor 76. The composition may also be as follows: the cleaning powder F in the cleaning powder storage tank 75 is fed to the filter container 11 via the feed pipes 77 and 78 by using the pump.

The cleaning powder supply unit 80 is not particularly limited, and a vane pump, a pipe pump, or the like may be used in addition to the above-described pressure-feed pump.

(cleaning powder F)

The cleaning powder particles F are powder and granules, and for example, spherical plastic beads, spherical glass beads, beads such as spherical perlite beads, spherical sponge such as spherical polyvinyl chloride sponge, sand such as silica sand, and the like can be used. As will be described later, the cleaning powder F rubs against the filter 12. Therefore, the cleaning powder particles F are not preferably particles having corners such as sand, but are preferably particles having rounded corners such as spherical particles or ellipsoidal particles, in order to prevent deterioration of the filter 12. In the same manner, the hardness of the cleaning powder F is preferably not high. Specifically, the hardness of the cleaning powder F is preferably R20 to R110. Therefore, the specific gravity of the cleaning powder F is not particularly limited, but examples thereof are Such as preferably 0.7 to 1.2g/cm ³ . In addition, the cleaning powder F is preferably a particle size suitable for recycling, i.e., classification. Specifically, the particle diameter is preferably 0.2 to 0.8mm, more preferably 0.4 to 0.8mm, and the above-mentioned particles having a particle diameter can be sufficiently used as the cleaning powder particles F. The particle size of the cleaning powder F was measured according to JIS Z8800.

(vibrator 73)

The filter system 1 illustrated in fig. 1 is provided with a vibrator 73, and the vibrator 73 vibrates the filter 12 in a state where the cleaning powder F is stored in the filter container 11, and rubs the filter 12 against the cleaning powder F. The vibrator 73 has: a filter vibrator 70 mounted on the bottom surface 21d of the filter membrane 12 m; a gas supply pipe 72 for supplying the gas AR from outside the filter device 10 to the filter vibration device 70; and a gas exhaust pipe 71 for conveying the gas AR for vibrating the filter vibration device 70 to the outside of the filter device 10. The filter vibration device 70 is not particularly limited. In fig. 1, a vibrator (piston vibrator) is used as the filter vibration device 70, but a ball vibrator, an electromagnetic solenoid, a pneumatic vibrator, or the like may be used instead. The attachment position of the filter vibrator 70 may be changed as appropriate, and may be attached to the top surface 21u of the filter membrane 12m or the inner surface of the tubular body 12s, for example. Since the cake K adheres to the outer surface of the filter membrane 12m, when the filter membrane 12m is vibrated by the vibrator 73, the cake K also vibrates together with the filter membrane 12m, and thus the cake K is easily peeled off.

As shown in fig. 8, the vibrator 73 may have a cleaning powder vibration device that vibrates the cleaning powder F stored between the filter vessel 11 and the filter membrane 12 m. The cleaning powder vibration device is not particularly limited. For example, a vibrator as a cleaning powder vibration device may be provided between the filter vessel 11 and the filter membrane 12m, and the cleaning powder F may be vibrated by the vibration of the vibrator. Alternatively, as shown in fig. 8, a gas discharge device 73a as a cleaning powder vibration device may be provided between the filter vessel 11 and the filter membrane 12m, and the cleaning powder F may be vibrated by the gas discharged from the gas discharge device. Alternatively, a high-frequency vibrator, an ultrasonic vibrator, or the like may be provided to vibrate the cleaning powder or granule F. In this way, in the method of vibrating the cleaning powder particles F by the vibrator 73, the filter membrane 12m is not directly vibrated as in fig. 2, and therefore the filter membrane 12m is less likely to be damaged than in the method of fig. 2. In addition, although it is difficult to lengthen the distance (vibration distance) by which the filtration membrane 12m is vibrated in the manner in which the filtration membrane 12m is directly vibrated as shown in fig. 2, in the manner in which the cleaning powder particle F is vibrated by the vibrator 73 as shown in fig. 8, the vibration distance of the cleaning powder particle F can be lengthened, and therefore the friction between the filtration membrane 12m or the filter cake K and the cleaning powder particle F can be further enhanced.

Further, both the filter vibration device 70 that vibrates the filter 12 and the cleaning powder vibration device that vibrates the cleaning powder F may be provided. By providing both, the peeling force of the cake K can be enhanced as compared with the case where only one is provided.

(discharge Unit 90)

In embodiment 1 shown in fig. 1, a discharge means 90 is provided for blowing pressurized gas CA2 into the filter container 11 to discharge the cleaning powder particles F in the filter container 11 from the filter container 11. The discharge unit 90 has: a gas compressor 85 that generates compressed gas CA2 (compressed gas for discharge) for discharging the cleaning powder F from the filter vessel 11; and a supply pipe 81 for supplying the compressed gas CA2 to the filtration vessel 11.

The discharge unit 90 may not be a unit using the compressed gas CA2 as shown in fig. 1. For example, a storage tank (not shown; storing a liquid for discharging the cleaning powder particles F from the filter vessel 11) and a pump (not shown; pressure-feeding the liquid for discharging) may be provided instead of the gas compressor 85. The liquid for discharge in the storage tank may be supplied to the filtration vessel 11 through the supply pipe 81 by using the pump.

The discharge unit 90 is not particularly limited. For example, as the discharge means 90 other than the above, a vacuum pump, an ejector, or the like may be used.

(check valve 95)

It is preferable that a check valve 95 is provided in the discharge pipe 16b of the cleaning powder storage tank 75. This is to prevent the turbid water from flowing back from the cleaning powder storage tank 75 due to the suction action of the pump 98 for the RO apparatus while the treatment liquid discharge pump 8 is stopped.

(filtration method)

An example of the filtering method is described below.

(filtration step)

First, the liquid to be treated a is filtered. Specifically, the valves V1 and V3 are opened, V2 is closed, and the treatment liquid discharge pump 8 is started. Then, the treatment target liquid a in the treatment target liquid storage tank 7 is supplied into the filtration vessel 11 through the supply pipe 13 of the treatment target liquid a. The flow rate of the liquid A to be treated supplied into the filtration vessel 11 is, for example, preferably about 0.001 to 0.004m/s (flux of about 50 to 200 LMH), and more preferably about 0.0017 to 0.0025 m/s.

The liquid to be treated a reaching the filter vessel 11 is filtered by the filter 12. Specifically, the treatment liquid a flows from the outside to the inside of the filter 12, and at this time, suspended substances in the treatment liquid a are captured by the filter 12. The liquid from which suspended matter has been removed from the liquid to be treated a by this filtration moves to the filtrate passage 12r through the filtration membrane 12m, and is discharged as filtrate B from the discharge port 11B through the liquid reservoir 51 and the filtrate discharge pipe 15. The filtrate B discharged from the discharge port 11B is sent to the filtering device 3 or the like at the rear stage through the discharge pipe 16.

Specifically, when the filtrate B is used as the domestic water DW other than drinking water, no further filtration is generally required, and thus the filtrate B is discharged to the outside of the system through the discharge pipe 16 c.

On the other hand, when the filtrate B is used as drinking water, further filtration is preferably performed, and therefore, the filtrate B is fed to the other filter device 3 via the discharge pipe 16a, and further filtered in the filter device 3, for example, to remove viruses and salts in the filtrate B. The filter device 3 is not particularly limited, and for example, an RO membrane filter device, an NF membrane (nanofiltration membrane) filter device, an ion exchange resin filter device, or the like can be used.

When the filtrate B is supplied to the filter device 3 and discharged as the domestic water DW to the outside of the system, it is preferable that the whole filtrate B is not supplied to the filter device 3 but a part thereof is supplied to the cleaning powder storage tank 75. The ratio of the amount of filtrate B fed to the filtering device 3 to the amount of filtrate B fed to the cleaning powder storage tank 75 is preferably 9:1 to 7: about 3. For example, it is preferable to provide a valve (not shown) at the branch point BP of the

discharge pipes

16a, 16B, 16c to adjust whether or not the filtrate B is fed to each

discharge pipe

16a, 16B, 16c and the amount of feed.

The filtrate B fed to the cleaning powder storage tank 75 is mixed with the cleaning powder F in the cleaning powder storage tank 75 to clean the cleaning powder F. Then, the filtrate (raffinate E) after washing the washing powder F in the washing powder storage tank 75 is discharged from the raffinate outlet 75a of the washing powder storage tank 75, and then discharged to the outside of the system through the raffinate outlet 86 and the valve V3. The residual liquid outlet 75a of the cleaning powder storage tank 75 is provided with a screen 99 to prevent the cleaning powder F from leaking out of the system from the cleaning powder storage tank 75.

As described above, the filtrate B goes to various routes according to the purpose.

On the other hand, in the filtration membrane 12m in which filtration is performed, the solids (suspended particles) of the liquid to be treated a adhere to and accumulate on the surface 12f of the filtration membrane 12m, and as a result, a cake K is formed. The liquid passage resistance per unit area of the filter 12 increases in proportion to the liquid passage accumulation amount (i.e., the amount of solid components separated from the liquid a to be treated).

The cake K formed on the surface of the filter 12 has some liquid permeability and has an advantage of functioning as an auxiliary filter of the auxiliary filter 12, but has a disadvantage that liquid permeability is deteriorated as the cake K is thicker in layers. That is, as the cake K becomes thicker, the hydraulic resistance becomes proportionally larger. Therefore, if a certain amount of cake K is accumulated, the liquid passage resistance of the filter 12 needs to be reduced, and the filtration flow rate needs to be increased. Therefore, when the amount of the filter cake K formed increases to a predetermined level, that is, when the filter 12 is clogged, the filtration process is ended.

Since the amount of the cake K produced is proportional to the turbidity of the liquid a to be treated and the accumulated amount of water (i.e., the amount of solid components separated from the liquid a to be treated), the filter 12 is clogged from the start of the filtration step, and the time between the cleaning step and the production of the cake K is determined by the time of production of the cake K. The filter clogging withstand voltage is, for example, 200kPa.

When the filtration treatment is stopped due to the formation of the cake K, the following structure may be used, for example: the internal pressure of the supply port 11A of the liquid to be treated a of the filtration vessel 11 is measured by a pressure gauge (not shown), and the internal pressure of the discharge port 11B of the liquid to be treated B is measured by a pressure gauge (not shown), and when the differential pressure thereof is equal to or higher than a predetermined value, the filtration step is terminated. It may also be determined by other methods whether to stop the filtering process. For example, the discharge amount of the filtrate B per unit time may be measured by a flow meter (not shown), and when the discharge amount is lower than a predetermined value, the filtration process may be ended. Further, the filter cake K may be judged according to whether or not a predetermined time has elapsed from the start of the filtration step, or the thickness of the filter cake K may be measured, and it may be judged that the filter cake K is in a state of being impossible to filter at the time when the thickness of the filter cake reaches about 1mm to 2 mm.

(cleaning step)

Next, a cleaning process after the filtering process will be described.

In the cleaning step, the cake K formed on the filter membrane surface 12f is peeled off, and the filter membrane surface 12f is returned to the original state. When this cleaning process is started, the valves V1 and V3 are first closed and the valve V2 is opened. Then, the gas compressor 76 is operated to generate a compressed gas CA1 (compressed gas for supply), and the compressed gas CA1 is supplied to the purge powder storage tank 75 via the compressed gas supply pipe 77. The mixed liquid ML (mainly, the liquid in which the cleaning powder F is mixed with the filtrate B) is stored in the cleaning powder storage tank 75, and the compressed gas supplied to the cleaning powder storage tank 75 causes the mixed liquid ML stored in the cleaning powder storage tank 75 to be discharged (extruded) from the cleaning powder storage tank 75. The mixed liquid ML discharged from the cleaning powder discharge port 75b of the cleaning powder storage tank 75 is supplied into the filter container 11 through the cleaning powder supply pipe 78 and the cleaning powder supply port 11C.

At the start of the cleaning process, the liquid to be treated a is accumulated in the lower gap 50u and the side gap 50s, and the filtrate B is accumulated in the liquid reservoir 51. The mixed liquid ML fed from the cleaning powder storage tank 75 presses the liquid a to be treated which is retained in the lower gap 50u and the side gap 50s, and the liquid a to be treated is filtered by the filter 12. The liquid to be treated a is then passed through the filter 12 to obtain a filtrate B, which is then transferred to the liquid storage chamber 51, and then passed through the filtrate discharge pipe 15 and the discharge pipe 16, and then transferred to the filtering device 3, the cleaning powder storage tank 75, and the like at the subsequent stage.

In addition, the mixed liquid ML of the squeeze-target liquid a is also filtered by the filter 12. The liquid portion in the mixed liquid ML is then passed through the filter 12 to obtain a filtrate B, which is transferred to the liquid storage chamber 51, and then passed through the filtrate discharge pipe 15 and the discharge pipe 16, and then transferred to the filtering device 3, the cleaning powder storage tank 75, and the like at the subsequent stage.

On the other hand, the cleaning powder F in the mixed solution ML cannot pass through the filter 12 and is deposited on the outer surface of the filter membrane 12 (the portion where the cake K is formed on the filter membrane 12 is the outer surface of the cake K. The same applies hereinafter). The filter membrane 12 is first laminated to be thin only on the outer surface thereof, but the lamination amount thereof gradually increases, and the cleaning powder particles F enter the gaps 2n between the

adjacent pleats

2, 2 of the filter membrane 12m, and the gaps 2n are filled with a plurality of cleaning powder particles F (filled state). That is, the cake K formed so as to cover the outer surface of the filtration membrane 12m is in contact with the plurality of cleaning particles F entering the gap 2 n.

In this state, when the filter membrane 12m is vibrated by the piston vibrator 70 using the vibrator 73, the cake K formed on the outer surface 12F of the filter membrane 12m and the cleaning powder particle F rub against each other (the filter membrane 12m and the cleaning powder particle F rub against each other at a portion where the cake K is not formed on the outer surface 12F of the filter membrane 12 m), and the cake K formed on the outer surface of the filter membrane 12m is peeled off by the friction. The type and performance of the piston vibrator 70 are not particularly limited, and for example, when the air is 0.6MPa and 54L/min, a piston vibrator having a vibration frequency of 94Hz and a vibration force of 265N is preferably used.

The time from the start to the end of the vibration of the filtration membrane 12m can be arbitrarily determined, but is preferably about 30 to 180 seconds, more preferably about 60 to 120 seconds. If the vibration time is shorter than 30 seconds, the cake K may not be sufficiently peeled off, and if the vibration time is longer than 180 seconds, the vibration may be continued to waste power even though the cake K has been peeled off, and the restart of the filtration process may be delayed.

(post-treatment step)

After the cleaning powder F is peeled off from the filtration membrane 12m, the cleaning powder F, fragments of the cake K after the peeling, and the like are discharged from the filtration vessel 11, whereby the filtration process can be restarted.

When the post-treatment process is started, the valves V2 and V3 are first opened, and the valve V1 is closed. Then, the gas compressor 85 is operated to generate a compressed gas CA (compressed gas for discharge) for discharging the cleaning powder particles F from the filter vessel 11. Then, the compressed gas is supplied to the filtration vessel 11 via the supply pipe 81. The compressed gas supplied to the filtration vessel 11 extrudes the filtrate B provided in the liquid storage chamber 51, passes through the filtrate passage 12r and the filtration membrane 12m in this order together with the filtrate B, extrudes the cleaning powder particles F, fragments of the peeled cake K, and the like, which are positioned in the side gap 50s and the lower gap 50u, and is discharged (extruded) from the filtration vessel 11. Compressed gas CA, filtrate B, cleaning powder F, fragments of filter cake K, and the like discharged from the cleaning powder discharge port 5B of the filter vessel 11 are supplied to the cleaning powder storage tank 75 through the cleaning powder discharge pipe 79.

Among the compressed gas CA, filtrate B, the cleaning powder F, and fragments of the cake K, etc. sent to the cleaning powder storage tank 75, the compressed gas CA, filtrate B, fragments of the cake K, etc. other than the cleaning powder F are sent to the outside of the system from the residual liquid outlet 75a of the cleaning powder storage tank 75 through the residual liquid outlet 87. A screen 99 is provided near the residual liquid discharge port 75a of the cleaning powder storage tank 75 to prevent the cleaning powder F from leaking out of the system from the cleaning powder storage tank 75.

As described above, after the filtrate B, the cleaning powder F, and the cake K are discharged from the filter vessel 11, the above-described filtration process is restarted.

(other embodiments)

In the above description of the cleaning step of the filtration method, the mode of vibrating the filter 12 is shown, but as described above, a cleaning powder vibration device may be provided between the filtration vessel 11 and the filtration membrane 12m, and the cleaning powder F may be vibrated by the cleaning powder vibration device. Alternatively, both the filter vibration device 70 for vibrating the filter 12 and the cleaning powder vibration device for vibrating the cleaning powder F may be provided, and the peeling force of the cake K may be further improved when both the filter 12 and the cleaning powder F are vibrated.

Further, for example, the cleaning vessel 18 may be provided separately from the filtration vessel 11, and the filtration membrane 12m may be cleaned not in the filtration vessel 11 but in the cleaning vessel 18. In this case, the cleaning powder particles F are deposited in the cleaning vessel 18 in advance, and the filter 12 is moved from the filter vessel 11 to the cleaning vessel 18 when the filtration membrane 12m is cleaned, and the filter 12 is immersed in the deposited portion of the cleaning powder particles F. Then, the filter membrane 12m or the cake K formed on the outer surface of the filter membrane 12m is rubbed against the cleaning powder F, and the cake K is peeled off and cleaned. In this way, after the filter 12 is cleaned inside the cleaning vessel 18, the filter 12 is returned to the filter vessel 11 again, and the filtration process is quickly restarted. The method of moving the filter 12 between the filter container 11 and the cleaning container 18 is not particularly limited, and for example, a crane unit or the like may be used to exchange the filter from the upper portion of each

container

11, 18.

(vertical dehydration dryer and horizontal dehydration dryer)

In the above description, the vertical filter device 10 in which the axial center of the filter 12 is vertical has been described, but the horizontal filter device 10 in which the axial center of the filter 12 is horizontal may be used.

(effects of filtration System and filtration method)

Since the filter system 1 and the filtering method do not use the disposable filter 12, occurrence of a failure which is likely to occur when the filter 12 is replaced can be suppressed. Further, since cleaning can be automated by programming the timing of cleaning the filter 12 in advance, no manual work is required for operation, and unmanned continuous operation can be achieved. Thus, no special expertise is required for the operation of the system, and anyone can simply operate. In addition, clean water can be stably produced regardless of the turbidity of the liquid to be treated A. Further, since the type of spraying the cleaning water to the filter 12 is not adopted as in the conventional patent document 1, the filter 12 is not easily damaged during cleaning, and the filter 12 can be made durable. Further, since the disposable filter 12 is not used and the filter 12 is not rotated or sprayed with the washing water at the time of washing as in the conventional patent document 1, various kinds of power can be suppressed, and thus the operation cost is low. Further, since a rotary unit or the like of the filter 12 is not required as in the conventional patent document 1, the entire apparatus can be simplified, the manufacturing cost can be reduced, the weight can be reduced, and the transportation can be facilitated.

Symbol description

1 … filtration system, 2 … pleats, 2B … pleat base end, 2n … pleat-to-pleat gap, 2p … pleat tip end, 2w … (membrane thickness of filtration membrane), 3 … other filtration devices (example: RO membrane filtration device), 5a … cleaning powder supply port, 5B … cleaning powder discharge port, 7 … (treatment liquid) reservoir tank, 8 … pump (treatment liquid discharge pump), 9 … foreign matter removal device (example: coarse filter), 10 … filtration device, 11 … filtration vessel, 11A … treated liquid supply port, 11B … treated liquid discharge port (filtrate discharge port), 11C … cake discharge port, 12 … filter, 12B … filtration membrane back surface (filter inner surface), 12f … filtration membrane surface (filter outer surface), 12m … filtration membrane, 12r … filtrate passage, 12s … cylinder, 12t … filtration membrane upper end, 12u … filtration membrane lower end, 13 … (treated liquid) supply tube, 14a … upper side filtration membrane seal portion, 14B … lower side filtration membrane seal portion, and 15 … filtrate discharge pipe, 16 … discharge pipe, 16a … discharge pipe (to other filtering device), 16B … discharge pipe (to cleaning powder particle storage tank), 16C … discharge pipe (for obtaining domestic water (excluding drinking water)), 18 … cleaning vessel, 21d … filter membrane bottom, 29 … filter support, 50 … gap, 50s … side gap, 50u … lower gap, 51 … liquid storage chamber, 70 … filter cleaning device, 71 … gas discharge pipe, 72 … gas supply tank, 73 … vibrator, 74 … compressed gas supply tank, 75 … cleaning powder particle storage tank, A raffinate discharge port 75a, a purge powder discharge port 75B, a gas compressor 76 (purge powder supply gas production apparatus), a compressed gas supply pipe 77, a purge powder supply pipe 78, a purge powder discharge pipe 79, a purge powder supply unit 80, a supply pipe 81 (of compressed gas for discharge), a gas compressor 85 (purge powder discharge gas production apparatus), and a support unit 86 (example: support rods), 87 raffinate discharge pipes, 88 partition walls (e.g., silicon sponge), 88a partition wall inner wall (inner side wall), 88B partition wall outer wall (outer side wall), 88c partition wall through-hole, 90 discharge unit, 95 check valve, 98 (RO device) pump, 99 mesh (e.g., metal mesh), A treated liquid, AR gas, B treatment liquid (filtrate), CA1 (supply) compressed gas, CA2 (discharge) compressed gas, DW domestic water, E raffinate, F-washed powder, K cake, ML mixed liquid, N distance from filter membrane 12m from filter vessel 11 side inner wall, P pump, V1-V3 valve (pinch valve), length between L1 fold front end and fold front end, length between L2 fold base end and fold front end, CD, LD height direction, US (height direction) upper side, DS (height direction) lower side, GS fold extension direction, HS front end side, BS base end side, FT … Filter movement Path

Claims

1. A filtration system characterized in that it has:

and a vibrator that vibrates at least one of the filter and the cleaning powder and rubs the filter against the cleaning powder and the cleaning powder in a state where the cleaning powder volume is present outside the filter.

2. A filtration system characterized in that it has:

a cleaning container for cleaning the filter;

and a vibrator that vibrates at least one of the filter and the cleaning powder and causes the filter to rub against the cleaning powder and the powder in a state in which the filter is moved to the cleaning container and the cleaning powder volume is stored outside the filter.

3. The filter system according to claim 1 or 2, wherein the filter is a pleated filter that is formed by corrugating a flat filter medium to form a plurality of pleats and is formed in a cylindrical shape.

4. A filter system according to claim 1, further comprising a discharge unit that blows pressurized gas into said filter container to discharge said cleaning powder from said filter container.

5. A filtration system according to claim 1, wherein a partition wall is provided to cover an upper end portion or a lower end portion of the filter to partition a space where the liquid to be treated is present from a space where the liquid to be treated is present,

the partition wall is an elastic partition wall.

6. A filtration system according to claim 1, wherein a partition wall is provided to cover an upper end portion or a lower end portion of the filter to partition a space where the liquid to be treated is present from a space where the liquid to be treated is present,

A storage chamber for storing the treatment liquid is provided in the filter container on the opposite side of the filter from the partition wall.

7. A filtration method for filtering a liquid to be treated by using a filtration system comprising:

the filtration method is characterized in that,

comprises a cleaning step of removing a cake formed on the outer surface of the filter by filtration of the liquid to be treated,

in the above-mentioned cleaning process, in the course of cleaning,

at least one of the filter and the cleaning powder is vibrated, and the filter cake formed on the outer surface of the filter is abraded by the cleaning powder.