JPH06126106A - Filtering method and apparatus - Google Patents

Abstract

PURPOSE:To make filtering method applicable for production processes, etc., by installing a filtration unit in a frame, capturing particles on the outer face of the filtration unit, and discharging them to a collective system by every filtration unit, wherein a filtering material is attached to and a discharging route of a filtered liquid is installed in the filtration unit, regarding filtration of air, etc. CONSTITUTION:Filter cloth 4 is formed into like a bag and a filter plate 6 is put in the bag and the resulting body is attached to a filtration frame 2 by fastening bolts 46 to compose a filtration unit 3. The filtration units 3 are independent respectively and are arranged in a filtration tank in the way the neighboring filtration frames 2 are placed at slightly different but close positions as if they are overlapped. Both sides of respective filtration frames 2 are closed with bellows 28 and the bottoms are railed with an elastic pipe rail 33 which is expanded with air and deflated. Also, the upper and the lower ends are held by hanging metal fittings 24 and feets 25 the gap among the filtration frames 2 are maintained in parallel. A raw liquid, etc., which is supplied from a distributer 1 comes to the filtration frames 2, is filtered by the filter cloth 4, and the filtered liquid flows down in a passage 6, collected in a collecting pipe 8, separated from air by a separator 9, and the air and the liquid are discharged by a vacuum pump 11 and a pump 10, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for filtering a fluid or dehydrating mud in a large amount and with high efficiency. Not only is it suitable for treating difficult-to-treat substances, but it is also a filtration or dehydration method applicable to industrial production processes, environmental measures, etc., and can also be used for pretreatment thereof.

[0002]

2. Description of the Related Art Conventionally, there is no simple method suitable for filtering a large amount of water, mud, sludge, etc. from road gutters, gas station oil mud, sewers, lakes, rivers, port mud, land, etc. Filter cloth, processed filter paper, filament winding type expensive filtration equipment and dewatering equipment used in the industry, or in mud treatment, use cement or lime-based dewatering and solidifying agent to reduce water content before landfill disposal It was difficult to implement because there is no other way to do it and the cost is high. Even in the industrial process, filtration and dehydration are costly and take up an installation place. The filter / press type was heavy and large when the filtration area was increased to increase the filtration capacity, and not only the size was increased, but also the time required for the cake discharging step was lengthened and the cost was difficult to be reduced. Further, the replacement of the filter material is troublesome, and the filament winding type filter element is disposable and costly.

[0003]

In the conventional method, there is a problem of clogging of the filter body, moreover, it is expensive due to the complexity of the mechanism, and the power consumption is large. There is a problem, and for large-scale processing, the conventional filter has a large device and a large installation area for its filtering capacity.
The expensive ones, which are troublesome to replace the filter cloth, and those containing colloidal particles, use a large amount of the filter aid, and it is difficult to dispose of the mass waste cake or mud. It is an object of the present invention to provide a compact and large capacity, relatively inexpensive and flexible filtration method and device. Moreover, in the conventional environmental measures,
Centrifugal dehydration to increase dehydration or separation efficiency with high capacity,
A belt press, an automated filter press, a screw press, and the like were considered to be suitable, and they were used properly according to the purpose. This is because it was thought that the separation efficiency of water was good. However, the power consumption of these is large, or the equipment cost is high. Moreover, the equipment that can be used is limited depending on the purpose, and it is necessary to use an expensive filter and a large amount of filter aid that have been used in the conventional production process in order to simply remove a large amount of hydrophilic suspension chamber of water. It was often impractical in terms of cost except in special cases.

[0004]

[Means for Solving the Problems] Vacuum filtration is simple, but cake filtration cannot achieve a large differential pressure and is inefficient compared to pressure filtration. The vacuum rotary drum type has a small filtration area. There were difficulties. The present invention has a vertical or horizontal filtering surface, and is similar to a filter press, but has a thin filter material, a filter plate, and a filter frame that are stacked to reduce the weight, resulting in a large area, downsizing, faster opening and closing of the filter frame, and higher frequency. The filtration resistance is increased with a thin cake thickness, or the filtration speed is increased by using the non-clarification filtration phenomenon, the vibration of the filter material clogging, the removal promotion by the reverse blow, and the pressure filtration even by the vacuum filtration. It enables higher efficiency and higher dewatering rate. That is,
(1) Thin the filter plate to increase the filtration area that can be accommodated in the unit volume. (2) Increase the filtration speed by thinning it. (3) Increase the cake discharge frequency by reducing the cake thickness. Therefore, the increase of the actual operating time is caused by the expansion / contraction speed of the filter plate, which is an expander / contractor that is originally an operating machine, such as a pantograph type or a magic hand type, and a hinge is used together to maintain the interval. By maintaining a relatively narrow space between the two, it is possible to smoothly remove and remove the cake. (4) The filter frame is made thinner to make the filter plate thinner, and strength reduction is caused by the filter plate or frame material selection (steel, stainless steel). Etc.), the shape is a circle or a corner with a trapezoidal edge,
When a cake is formed by reinforcing with a steel mold, unevenness, a shell structure, etc., its thickness is 0-25 mm, preferably 5-15 mm
It is a frame reinforcing structure that allows the filtering surfaces to approach each other so that they can be overlapped, the filtering surfaces can be approached, and the bending strength of the surfaces is made small so as not to hinder the opening and closing operation of the filtering frame, thereby making it thin. The weight can be reduced. As a result, the sliding or vibration effect is improved, and conversely the vibration can increase the opening and closing speed and increase the frequency. In addition, the frame itself holds a gap passage without a bottleneck so as not to prevent the supply of mud from the side frame and the discharge of the cake. (5) Shifting the temporal phase of the filtration operation of a pair of adjacent filtration surfaces (6) Reverse blowing for removal of blocked particles is performed sequentially or simultaneously for each filter medium or filtration chamber, and filtration is also performed. The plates and pipes are made relatively thin, and the time and power loss at high frequency are reduced by the appropriate arrangement of the switching valve. (7) Breaking the cake filtration mechanism When there is a turbidity problem in the previous operation, the adjacent filtration A fluid is made to flow in series on a surface or a plurality of grouped filtration surfaces, and by superimposing non-clarification filtration, the same effect as that of clarification filtration can be obtained and a large amount of low-cost treatment can be performed (8) Non-clarification filtration , Mass treatment by cake or waste sludge discharge by high-frequency opening and closing, if necessary, the filtrate is then clarified and filtered, and the filter plate is opened and closed by low-frequency opening and closing operation. By destroying the bridge Dehydration promoting, cake peeling, inclined filtering surface, facilitating discharge from the small clearance,
Smoothing of opening and closing by floating the filtration frame, (10) installation of a filter cloth surface lattice for dividing the cake, (11) fluid passage inside the filtration unit due to the deposition pressure of the cake deposited on the outer lower part of the filtration unit by vibration or reverse blow It is possible to filter a large amount of water, muddy water, mud, oil mud, etc. Do it at low cost. If necessary, it enables a new type of clarification filtration or dewatering of mud. The effect of reducing the distance between the filter plates is, for example, by setting the pitch to 10 mm, about 100 filter plates can be accommodated in 1 m, and two filter cloths can be placed on both sides of each filter plate. As a result, a total of about 200 filter cloths can be put in, and in the case of a filter cloth of 1 m × 2 m, the filter area can have a filter surface corresponding to a large filter of 200 m ² . Moreover, in addition to being compact and lightweight, the filter plate can be opened or closed by using a device that opens and closes each filter frame individually or simultaneously by combining pantograph type, magic hand type or arm etc. Allows the treatment of liquids and muds containing occlusive particles. . This is 10-100 times faster than the conventional type of several minutes to several tens of minutes. This is a large increase in capacity that could not be considered in the past when the cake thickness is reduced and the filtration rate is increased 5 to 10 times. Further, the weight reduction of the filter frame and the like makes it possible to give more powerful vibration because the vibration power becomes smaller in proportion to the mass reduction, and therefore the interval is narrow like the supply of mud and the operation is difficult. Due to the small distribution distance, the material is evenly distributed over a large number of filtration surfaces, and by vibrating during filtration, even the ones that are difficult to dehydrate due to the close packing effect of the particles that make up the cake It can be easily dehydrated to reduce the water content of the cake. It facilitates the exfoliation and discharge of a filter cake or the like from a filtration device having a small filter plate pitch in which it is difficult to discharge a mud or a filter cake with reduced fluidity, and further lowers the liquid content of the cake. The vibrating mechanism is configured by mechanically connecting a vibrating machine to the entire device or a filter frame, a filter plate, or a filter cloth, but it may vibrate the liquid in contact with it, or pressure fluctuations due to suction or pressurization. May be The vibration may be intermittent, and a required time, a suitable frequency, and a vibration having a required strength can be selected and given by a test. Moreover, the reverse blow for cleaning the filter cloth can be combined with vibration, which increases the discharge speed of the cake and the like and increases the actual operating time, thereby further increasing the filtration capacity of the apparatus. It has been customary to stack filter cloths in multiple layers in order to improve the filtering effect, but even if the blocked particles are backwashed, they are captured again by another filter cloth, and when they are stacked in multiple layers, they are backwashed in the same manner as the filament winding element. I couldn't. In the present invention, since each thin filter cloth or filter layer can have a structure in which the discharged fluid at the time of backwashing is discharged, there is no phenomenon of re-entrapment of pollutant particles, and the filtering material is regenerated by clarification filtration of a large amount of fluid. It enables to operate at low cost. The discharge path of the blown fluid can be selected depending on the purpose of opening the filter frame or providing a discharge path that can be discharged while the filter frame is closed. The kind of filter cloth, thickness, and filtration conditions can be determined by a test. In addition, although it is relatively highly efficient, it is possible to perform non-clarification filtration, which was difficult due to internal clogging of the filter media.By multiplexing this type of filtration operation or using filter media in series, filament winding filter elements can be used. Even in the clarification filtration operation corresponding to the typical filtration mechanism, it is found in the conventional filtration device by operating while reverse-blowing the filter medium with or without using a relatively small amount of the filter aid. It solves the problem of high cost or treatment of substances that are difficult to filter or dehydrate. Various problems occur in the apparatus in order to reduce the interval between the filter frames and to utilize this to perform multiple filtration.
(1) In order to connect an independent suction system to each filtration chamber, it is necessary to have a thin outlet that allows a relatively large flow rate. In the present invention, by using a slit type cross section for this outlet and changing the position of the outlet from the adjacent filter frame, it is possible to provide an appropriate flow resistance and to achieve a flow rate distribution and a large flow rate. (2) In order to supply the undiluted solution or the mud-like material to each filtration surface, gaps are provided between the filtration frames so that particles at substantially equal intervals can pass through. (3) Moreover, since the intervals between the filter frames are close to each other, they can be overlapped. (4) As the filtration or dehydration progresses, the thickness of the cake changes and the filtration conditions such as the filtration speed change. The change is measured to measure the filtration capacity, mud treatment capacity, cake deliquoring rate, and filter clarification. Optimum conditions can be obtained from tests or calculations based on degrees, and can be set automatically or manually. In vacuum filtration, the filtration pressure is limited to a relatively narrow range, so the main variables are the cake thickness, and therefore the filter frame interval, the blow interval and the blow time, and the cake peeling discharge interval that can be set independently of the blow. , You can set them arbitrarily. The shape of the frame can be selected from corners or circles, and by combining ellipses or curves, a shape that can easily withstand the vacuum suction pressure toward the inside can be selected. The thin metal plate has an advantage that it is easy to press-mold the frame and the filtration unit, and it becomes possible to mass-produce a large number of filtration frames, filtration plates and the like. In particular, a curved shape is suitable because it is easy to mold and has high strength. Although this filtration device can supply undiluted solution or mud from the supply port arranged above, it can be manufactured in a relatively small size and lightweight, so it can be placed in a water tank, a waterway, a pond,
It becomes possible to use it so that it can be submerged in lakes, harbors, etc. and concentrated and discharged into water. In this case, a room for discharging the cake or the concentrated mud is made under the device by a stand, hanging, etc., and the discharged cake can be moved by other means such as dredging, a bucket, a screw and a pump. It is efficient that the transferred substance is further dehydrated according to the present invention.

[0005]

First Embodiment The present invention will be described with reference to the drawings. FIG. 1 is a front view of a filter device according to the present invention, showing a cross section in which a filter frame 2 and a filter cloth 4 are formed into a bag shape and a filter plate 6 is put therein and stretched on both sides. Each filter frame unit is independent and is fixed by the reinforcing structure 2 and the tightening bolt 46. Since the positions are staggered by the adjacent filter frames, and holes are made in the adjacent frame or the press fitting at positions corresponding to the bolt head and the nut,
You can approach and superimpose them. Both sides of the filter frame are closed by bellows 28 or a flexible wall, an elastic sheet, packing or the like, and the bottom is closed by an elastic tube seal 33 that expands with packing or air and contracts with vacuum. The upper and lower sides of the frame are restricted in vertical movement by hanging (or pressing) metal fittings 24 or feet 25. The open / close intervals between the filter frames are mechanically held parallel to each other at both ends, and a movable frame 27 for holding the posture of the filter frame with a pulley or a slide 32 is driven by a motor or pneumatic pressure, and a shaft 30 by a hydraulic cylinder 14. Then, by moving, the magic hand type opening and closing, the interval holding device 40 is expanded and contracted to open and close, the filter frame is held in parallel and the interval is maintained, the opening and closing is fast, and the cake formation and discharge are easy and efficient. become. Undiluted solution or liquid-containing mud also serves as a classifier
It is supplied by the distributor 1 which is vibrated by, and falls from the upper part through the gap passage of the frame, the mud particles are trapped by the filter cloth to form a cake, the liquid permeates the filter cloth, and is sucked into the inside of the filter plate 3. ,
It flows down through the packing material or passage 6, enters the separator 9 together with air from the passage 39 conduit 7 attached to the filter plate frame 36 into the collecting pipe 8, the air is sucked by the vacuum pump 11, and the liquid is discharged by the pump 10. To be done. After the cake is formed about 5-20 mm, the liquid supply is stopped, the valve 41 is closed, and the moving frame 2
7 is moved to operate the magic hand 40 to open the filter frame, and while vibrating the filter frame by applying the vibrator 12, the reverse blow air valve 42 is opened and the cake is dropped. After closing the air valve and filter frame, the next filtration cycle is entered.
The magic hand 40 has one end fixed to the fixed frame 16 with a fulcrum 18, and a fixed fulcrum 18 of each frame, and a fulcrum 1 that moves according to opening and closing.
9 and arm 20. The arm 120 can be used together with a drive / parallel maintaining mechanism similar to a table lifter. 1
2 and 13 are vibrators, and it is preferable to use 12 for the filter frame 31.
Reference numeral 5 is a green filter plate holding frame, and 26 is an end face filter plate. FIG. 2 shows a liquid passage formed by cutting out a part of the filter frame 36, and 44 is a connecting conduit, which is suitable to have a thin corner, ellipse or circular cross section. 34 is a tightening tool. FIG. 3 is an AA cross section of FIG. 2 and shows 38 thin walls, and 37 is an insert or a honeycomb structure. FIG. 4 shows a structure for fluid outflow inside the lower part of the filter plate 6. Reference numeral 51 is a vertical insert, such as a blind-shaped insert, a cage insert, or a grooved plate or corrugated plate, and 50 is a horizontal insert. 44 and 48 are tubes, and 48 may be used for suction. FIG. 5 is a plan view of one of a filter plate and a filter frame covered with a filter cloth (corresponding to a right side view with respect to the filter surface of FIG. 1). FIG. 6 is the filter plate of FIG. 1 attached to the filter frame. FIG. In FIG. 7, the reinforcing portion 2 of the filter frame has a cross-sectional shape of a shape steel, and it can be overlaid with an adjacent frame to be accessible. FIG. 8 shows an example in which a filter plate is sandwiched between two frames 5. FIG. 9 shows an example in which the tightening bolt is made outside the frame edge. In the same manner, the fitting of the fulcrum 18 of the magic hand or the spacer can be attached to the filter frame. However, in order to simplify the replacement of the filter cloth, the stop bolt may be reinforced by only one piece of the frame 2 and penetrated and tightened. The bag-shaped filter cloth is advantageous for preventing leakage.

[0006]

[Embodiment 2] FIG. 10 shows one filter device in which two filter cloths are connected in series.
Figure 3 shows a schematic diagram of a flow passing through times. The liquid or mud enters the filter through one or a plurality of supply ports 57, passes through the filter cloth 4, enters the inside of the filter body 6, flows down, passes through the pipe 7 and the second-stage supply quality 7
7 and is further filtered, discharged into a pipe 8 and discharged by vacuum suction. Reference numeral 79 is a filter aid tank supplied to 57 or 77, and particularly a small amount of the second-stage supply is required, and the amount of discharged cake can be reduced.

[0007]

[Embodiment 3] FIG. 11 is a schematic system diagram of a two-stage filtration in which a filter plate corresponding to one sheet is divided into two chambers, suctioned from an upper chamber 6 to a chamber 71, and further discharged from a pipe 8 through a chamber 66. . Upper chamber 3
The cake discharge from No. 1 can be smoothly performed by inclining the filtering device and using a vibrator. The connecting passages 6 and 66 can be formed by the internal structure of the filter plate or external piping, and the former is simple.

[0008]

[Embodiment 4] FIG. 12 is a flow sheet showing the operation of changing the start time of filtration on the opposing filtration surfaces. The suction was switched to the C system near the end of filtration on the filtration surface belonging to the B system to improve efficiency.

[0009]

[Example 5] Swine wastewater having a COD of 300 ppm was vacuum-filtered. A thin cloth made of thin polyester single thread or multi-thread having a single thread diameter of 0.1 mm and a cloth thickness of 0.25 mm was used as a filter cloth and was filtered while being reverse blown with air at 1-minute intervals while also using vibration. By this operation, filtration could be continued. A small amount of coal or woody or other organic carbide was added at each repetition or mixed with the waste water and filtered. The spacing could be doubled with the additive and the capacity increased by 40%. 40% of COD is removed by 1-pass filtration, 55% by 2 passes
I was able to remove it. The COD removal rate of 40-60% was obtained by filtering the domestic wastewater from the dwelling. For the filter cloth, synthetic fiber is suitable for cake separation and particle separation. (Control example) When reverse blow was not performed, filtration could not be continued because of blockage.
No. 7 COD of the above waste liquid and waste water could be removed a few times even when filtering using quantitative filter paper, but even if a filter aid was used, the filter paper clogged compared to the single yarn or multi-thread when reverse blown. It was found that the filtration rate was rapidly decreased by the above, the regeneration was incomplete and the life was short.

[0010]

[Example 6] The operation corresponding to Example 4 was applied to the treatment of bentonite sludge discharged from the earth drill method used for in-situ pile driving in civil engineering work. Using the vibration, the 50% water content cake could be reduced to 43% cake water content under the same conditions. When the water content is the same, the time required is 1 /
It became 3.

[0011]

[Embodiment 7] In FIG. 12, when the filter plate 6 inside the side plate 77 is used as a pressing surface and vibration is applied while pressurizing with the power 14 as shown in FIG. 1, the liquid removal effect is further enhanced and the time required can be shortened.

[0012]

As described above, according to the present invention, a number of filtering surfaces are arranged lightly and densely within a unit volume and a unit installation area by reducing the thickness and weight of the filtering surface. Uses a knob arm type operation and spacer that restricts the height of the fulcrum such as magic hand type distribution.
It increases the opening and closing speed, shortens the cake discharge time, which was a problem in the past with high cost, enables the removal of liquid with a large amount of solids and mud, and is useful for the treatment of waste and waste. . It is necessary to take the filtered fluid from the thin filtration surface, connect it to ordinary piping, and quickly discharge the thin cake formed on the many thin filtration surfaces from the thin gaps. Applying vibration after blowing or while blowing as necessary, it is easy to vibrate with a small amount of power because it is lightweight and compact, and the time loss of increased discharge frequency by thinning the cake is as described above. In the case of shortening, and in the case of fine particles, there is a tendency that liquid is left behind on the side opposite to the filtration surface by vibration filtration, but this is a complex problem such as shifting the filtration start time on the adjacent surface to solve various problems. It enables the synergistic use of problem solving. Liquids and colloidal particles containing compressive occlusive colloidal particles, which have been difficult to filter in the past, and organic sludge (for example, sewage, livestock excrement drainage, dredging sludge, water pollutants such as lake blue powder), etc. are frequently used in the apparatus according to the present invention. It became possible to perform backwashing and to treat it. In many cases, a liquid containing such a colloidal organic substance can be easily halved by filtration according to the present invention without treating microorganisms such as COD with microbial treatment. In addition, non-clarification filtration operation causes rapid wear of the filter material, so it was practically difficult to treat waste and wastewater.
The present invention makes it possible to use a thin filter cloth made of a thin raw yarn once or a plurality of times in the present invention. As described above, it is practically possible to carry out filtration and dehydration treatment of substances which have been conventionally difficult, and it is particularly effective in solving environmental problems.

[Brief description of drawings]

FIG. 1 is a front view of a filtering device. It is explanatory drawing (front sectional drawing).

FIG. 2 is a vertical cross-sectional view of connection from a filter plate or a filter frame to a vacuum suction pipe. FIG.

FIG. 3 is an explanatory diagram of an AA sectional view operation of FIG. 2;

FIG. 4 is an explanatory plan cross-sectional view showing an example of the connection relationship of the outlets corresponding to FIG. 2 or FIG.

FIG. 5 is a plan view of a filtration unit plate.

[FIG. 6]

[FIG. 7]

FIG. 8

9 is a cross-sectional explanatory view corresponding to a front view of the filtration unit plate of FIG.

FIG. 10:

FIG. 11 is an explanatory diagram of multiple filtration.

FIG. 12 is an explanatory diagram in which the filtration time is divided into two systems.

13 is an explanatory diagram corresponding to the side view of FIG. 4. FIG.

FIG. 14 is a cross-sectional explanatory view of a horizontal filtration apparatus with a small inclination on the filtration surface.

[Explanation of symbols]

 2 Filter frame or reinforcing frame of filter frame 3 Filter unit 4 Filter material, filter cloth 5 Holding frame 6 Filter plate or its inner chamber 7 Filtrate outlet 12, 13, 29 Vibrator 20 Magic hand or spacer arm 21 Rail running Movable fulcrum 33 Gasket or sealing rubber tube 37 Perforated or non-perforated honeycomb structure

Claims (13)

[Claims] 1. A filtration device comprising a plurality of filtration surfaces stacked together, provided with an uneven surface forming a frame for supporting a thin filtration surface at a peripheral portion, or a frame composed of reinforcing ribs forming an angle on the filtration surface. , A filter unit having a filter plate or a frame is attached to the frame, a filter material is attached to one or both sides of the filter plate or the filter unit, and a discharge passage for the filtered fluid is provided near the lower portion inside the filter face. A filtration method in which particles are substantially collected on the outer surface of the filtration unit, and the filtration fluid is discharged for each filtration unit while being collected and filtered. 2. A plurality of round or square filtration frames are constrained on one side surface or both side surfaces by a fulcrum provided on each frame portion, and are connected by an expansion / contraction and spacing maintaining mechanism that also serves as an opening / closing mechanism, and substantially the same. A filtration device that filters or opens and closes while maintaining the intervals. 3. A plurality of filtration frames are opened and closed during filtration and connected to a telescopic arm or hinge type telescopic device at a fulcrum portion so that one side surface or both side surfaces are held at substantially equal intervals and each filtration unit is simultaneously operated. In a filter device that opens and closes, filtration is performed while holding the filter frame at a predetermined interval, or the interval of the filter frame is automatically or mechanically changed during or at the end of filtration, and finally the interval is expanded to discharge the cake. The filtration method according to claim 1 or 2. 4. A filtration method in which each filtration unit is connected in a folding screen in a filtration device constituted by stacking two or more filtration surfaces and is opened / closed in accordance with a filtration step and a filter desorption step. 5. The filtering surface is a flat surface or a curved surface, and both ends of adjoining filtering surfaces are movably connected to each other every other end directly or via connecting metal fittings, and the other end is open. The filtration method according to claim 1 or 4, wherein the filtration methods are connected by metal fittings that limit the opening of time. 6. The filtration method according to claim 1, wherein the opening and closing of the filter frame is performed by pulling or pushing the filter plate in the thickness direction, and by restricting the position in the direction perpendicular to the thickness. 7. The filtration method according to claim 1 or 4, wherein filtration is performed while applying vibration intermittently or continuously, and reverse blowing is performed during filtration or when the cake is discharged. 8. The filtration method according to claim 1 or 4, wherein a partitioning or pressurizing membrane is provided under the filter medium on one side or the core side of the filter plate. 9. When the liquid is filtered, two filtration surfaces that make a pair with the filtration plate are formed, and one filtration surface is used first, and the opposing filtration surfaces of the adjacent filtration units of the formed cake are predetermined. The filtration method according to claim 7, wherein the suction method is used with a time difference. 10. The filtration method according to claim 1, wherein the filter frame is provided with a sealing expansion wall or tube and partially or entirely sealed during filtration or before discharging the cake to carry out filtration or dehydration operation. 11. The filtration method according to claim 7, wherein a pressure-resistant fluid passage is provided inside the filter body. 12. The filtration method according to claim 1, wherein a plurality of filtration material layers in which a plurality of filtration units are arranged are grouped into one or a plurality of layers, and the fluid passes through the plurality of layers in one pass of the apparatus. 13. The filtration method according to claim 12, wherein when the fluid to be treated passes through a plurality of thin filter medium layers in series, the supply of the filter aid and the backwash separation are performed for each outer surface of the filter medium layers.