JP3809648B2 - Moving filter filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a filtration device for suspensions of clean water, sewage, industrial wastewater, etc. In particular, the present invention uses a diatomaceous earth as a filter material, and circulates the contaminated filter material to wash and regenerate it. The present invention relates to a filtration device that can continuously perform clarification filtration.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an up-flow moving filter bed type filtration device in which a filter medium constituting a filter bed moves, this filter medium is moved, washed and regenerated, and returned to the upper part of the filter bed is known and well known. Then, granular sand having a specific gravity of 1.0 or more is used as a filter medium, an air lift pipe that operates with compressed air is used to transport the contaminated sand, and the filter medium layer is washed and regenerated with a cleaning device at the top of the filter tank. There is also a well-known filtration device that returns to the top of the water and discharges the washing waste water to the outside.
[0003]
In addition, in JP-A-6-47208, in a filtration apparatus using sand granular diatomaceous earth as a filter medium constituting a filter bed, raw water is supplied from a raw water supply pipe provided at the upper part of a sealed filtration tank, and then descended. The suspended matter is removed with a diatomaceous earth filter medium while passing through the filter medium layer in a flow, and the treated water is taken out from an extraction pipe provided at the bottom of the filtration tank. When the filter medium contaminated by the suspension is washed and regenerated, wash water is supplied from the take-out pipe, and the filter medium is passed through the filter medium in an upward flow so that the suspension adhering to the filter medium is removed from the filter medium. Peeled and dirty cleaning wastewater is discharged from the raw water supply pipe to the outside.
[0004]
[Problems to be solved by the invention]
FIG. 3 is a longitudinal sectional view conceptually showing a conventionally known upward flow moving filter type filtration device. Raw water is supplied to a supply port 31 provided at a lower portion of the filtration tank 30 and connected to the supply port 31. A loop-shaped header pipe 32 and a plurality of inflow pipes 33 erected on the header pipe 32 are equally supplied to the lower part of the filter medium layer 35 via the loop-shaped distribution umbrella 34. While the raw water supplied in this manner rises in the filter medium layer 35 formed of granular sand, impurities are captured by the filter medium layer 35, and the treated water is treated at the upper part of the filter tank 30. It is discharged out of the tank through the water outlet 36. The contaminated sand at the lower part of the filter medium layer 35 is supplied to the lower part of the air lift pipe 37 erected at the center of the filter tank 30 to raise the air lift pipe 37 and disposed at the upper part of the filter tank 30. The cleaning tower 38 is cleaned and regenerated with treated water. The cleaned filter medium 35 a is returned to the upper surface of the filter medium layer 35 while being distributed by the chutes 37 a and 38 a disposed in the cleaning tower 38 and the outer periphery of the air lift pipe 37. The contaminants cleaned in the cleaning tower 38 and separated from the filter medium 35a are discharged out of the tank from a cleaning drain 39 provided in the upper part of the cleaning tower 38. In the moving filter bed type filtration device using granular sand as the filter medium 35a described above, the surface of the filter medium particles is flat, there are no adsorption holes, and the particle gap is large, so that a fine colloidal suspension cannot be captured and the filter medium layer. Therefore, there is a problem that the quality of the treated water deteriorates.
[0005]
Further, in the invention described in JP-A-6-47208, diatomaceous earth is used as a filter medium, so that the above-mentioned problematic colloidal suspension is caused by diatomaceous earth having porous characteristics. However, since it is captured by the porous material unique to the diatomaceous earth, clarification filtration can be performed and the quality of the treated water is improved. However, in the method for cleaning a filter medium according to the invention described in JP-A-6-47208, it is necessary to stop the filtration operation during the cleaning, the continuous operation cannot be performed, the filtration device becomes large, and the installation area becomes large. In addition, because the washing method is simply backwashing the washing water, there is a problem that the suspension trapped in the porous part of the diatomaceous earth cannot be separated, and further, if the washing pressure is increased, the filter medium will be washed away. There are also challenges.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention forms a filter medium layer by laminating a granular filter medium heavier than water inside a sealed filter tank, and opens at a lower layer part of the filter medium layer and an upper part of the filter tank, The filter medium is pulled out from the bottom of the filter medium layer with compressed air and transferred upward, and an air lift pipe is installed so that the filter medium is washed and regenerated and circulated to the upper part of the filter medium layer. Diatomaceous earth was used, and raw water was press-fitted from the raw water supply port provided in the filtration chamber above the filter medium layer to lower the filter medium layer, and the treated water was taken out from the lower part of the filter tank. It is.
[0007]
In addition, a separation tank is disposed on the outer peripheral portion of the upper end opening of the air lift pipe installed in the filtration tank, and projects upward from the top plate of the filtration tank from the filtration chamber of the filtration tank to surround the separation tank. A cleaning tower is erected, a filter medium cleaning device is suspended from the top of the cleaning tower, the lower end of the cleaning device extends to the inside of the separation tank, and the filter medium cleaning discharge is disposed on the upper side of the cleaning tower. An outlet is provided, and the filtration tank, the cleaning tower, the air lift pipe, and the cleaning device are disposed substantially concentrically. An ultrasonic cleaner is used as the filter medium cleaning device, and the upper portion of the cleaning tower is used for air exhaust. A level meter and an air exhaust port are provided, and the air exhaust port is provided with a control valve that opens and closes in conjunction with the level meter.
[0008]
The treated water outlet provided in the lower part of the filtration tank includes a loop-shaped header pipe connected to the treated water outlet pipe, a plurality of outflow pipes erected on the header pipe, It is composed of a loop-shaped distribution umbrella that is provided above the outflow pipe and distributes the treated water flowing into the outflow pipe evenly, and is provided at the lower surface of the distribution umbrella and at the openings of the washing tower and the washing outlet. A filter was installed to prevent the loss of filter media.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Since the apparatus according to the present invention is configured as described above, the raw water press-fitted to the upper part of the filter medium layer is trapped by the filter medium (diatomaceous earth) while the contaminants (suspension) are descending the filter medium layer. The filtrate (treated water) is discharged from the lower part of the filtration tank to the outside of the tank. At the same time, by supplying compressed air to the air lift pipe, the filter medium at the bottom of the filter medium layer is pulled out, and the stacked filter medium gradually moves downward from above. The extracted filter medium is transferred to the upper separation tank while being stirred in the air lift pipe together with the treated water at the lower part of the filtration tank.
[0010]
In the air lift pipe, the foreign substances adhering to the surface of the filter medium are separated from the surface of the filter medium by being stirred during the transfer. Then, the filter medium transferred to the separation tank is subjected to ultrasonic vibration by an ultrasonic cleaner hanging in the separation tank, and the fine suspension trapped in the porous portion of the filter medium is peeled off. The filter medium overflowed from the separation tank settles in the washing tower, and is supplied to the upper surface of the filter medium layer while being distributed by the chute disposed inside the washing tower and the outer periphery of the air lift pipe. Then, the peeled light impurities overflow from the separation tank, and are then discharged out of the tank through the cleaning discharge port. At this time, even if a part of the filter medium is mixed in the cleaning wastewater, a filter for preventing the loss of the filter medium is stretched at the opening of the cleaning tower and the cleaning discharge port, so there is no risk of the filter medium flowing out. .
[0011]
The compressed air supplied into the air lift pipe rises together with the filter medium and accumulates in the upper part of the washing tower, so that the liquid level in the washing tower is pushed by the compressed air and gradually decreases. If this liquid level becomes lower than the washing drain port, it becomes impossible to discharge the washing wastewater outside the tank. Therefore, the liquid level is detected by a level meter provided at the upper part of the washing tower. The control valve provided at the air exhaust port is opened, and the compressed air accumulated in the upper part of the washing tower is released to the atmosphere. When the liquid level in the washing tower rises again and exceeds the set value of the level meter, the control valve is closed.
[0012]
On the other hand, the filtrate (treated water) that has passed through the filter medium and trapped impurities and has been clarified flows equally into the distribution umbrella from the lower surface of the loop-shaped distribution umbrella disposed below the filter medium layer. Since a filter for preventing the loss of filter media is stretched on the lower surface of the distribution umbrella, only the filtrate flows in, and this filtrate flows through the plurality of outflow pipes standing in the distribution umbrella. Collected from the treated water outlet pipe connected to the lower part of the pipe into a loop-shaped header pipe provided in the outer periphery of the filtration tank, and out of the tank from the treated water outlet provided in one place of the header pipe Discharged. Hereinafter, the moving filter bed type filtration apparatus of the present invention will be specifically described with reference to the drawings.
[0013]
【Example】
FIG. 1 is a longitudinal sectional view schematically showing a filtration device 1 according to the present invention. In FIG. 1, the filtration tank 2 is a hollow cylindrical hermetic container having a substantially conical lower portion, and a granular filter medium 3 forming a filter medium layer 4 is laminated below the filter tank 2. In the present invention, commercially available diatomaceous earth 3 a is used for the filter medium 3. Diatomaceous earth 3a is porous and has a large porosity, and has the characteristics that the strength of the particles themselves is high. And the filtration chamber 6 is comprised above the inside of the filtration tank 2, and the supply port 7 which press-fits and supplies raw | natural water is provided in the upper part of the filtration chamber 6. As shown in FIG. A treated water extraction part 14 f is provided below the filtration tank 2. The raw water containing impurities and suspensions is press-fitted and supplied into the filtration chamber 6 by a pump or the like from the supply port 7, descends through the filter medium layer 4, and the diatomaceous earth 3 a captures the impurities and suspensions. Then, it is discharged out of the tank from the treated water outlet 14f as treated water.
[0014]
The treated water outlet 14f has a treated water outlet 14 provided at one end of the treated water outlet pipe 14a, the other end connected to a loop-shaped header pipe 14b, and a plurality of outflow pipes 14c erected on the header pipe 14b. The loop-shaped distribution umbrella 14d is used. The header pipe 14b is provided outside the lower part of the filtration tank 2, and a plurality of outflow pipes 14c provided upright on the header pipe 14b pass through the conical portion of the filtration tank 2 and have an upper end opened in the filter medium layer 4. Yes. The distribution umbrella 14d is disposed so as to cover the upper end opening of the outflow pipe 14c. Since the filter 14e having an eye smaller than the minimum particle diameter of the filter medium 3 is stretched on the lower surface of the distribution umbrella 14d, the filter medium 3 is not discharged together with the treated water.
[0015]
The air lift pipe 5 is erected concentrically with the filtration tank 2, and the lower end of the air lift pipe 5 opens in the filter medium layer 4 near the bottom of the filtration tank 2. A compressed air supply port (not shown) is provided at the lower part of the air lift pipe 5, and by supplying the compressed air to the lower part of the air lift pipe 5, the filter medium 3 at the bottom of the filter medium layer 4 is attached to the bottom of the filtration tank 2. The inside of the air lift pipe 5 rises together with the treated water, and the stacked filter media 3 gradually move downward from above. Then, the filter medium 3 rising in the air lift pipe 5 is transferred upward while being stirred and washed with the filter medium 3.
[0016]
The upper end of the air lift pipe 5 is opened at the upper part of the filtration tank 2, the outer periphery of the opening is connected concentrically with the bottom surface of the cylindrical separation tank 8, and the upper surface of the separation tank 8 is hermetically sealed. It is open in the tank. A cylindrical washing tower 9 is concentrically arranged so as to surround the outer periphery of the separation tank 8, the lower end of the washing tower 9 is opened in the filtration chamber 6, and the upper end is the top plate of the filtration tank 2. The top plate is provided at the upper end. A washing discharge port 11 is provided on the upper side of the washing tower 9 at a position outside the filtration tank 2, and an opening of the washing discharge port 11 and the washing tower 9 has a finer filter than the minimum particle size of the filter medium 3. 11a is stretched. A cleaning device 10 is suspended in the center of the top plate of the cleaning tower 9, and its tip extends to the inside of the separation tank 8. When the diatomaceous earth 3a is used for the filter medium 3, it is most effective to use the ultrasonic cleaning machine 10a that vibrates the diatomaceous earth 3a particles by ultrasonic waves. Is effective in the range of 20 KHz to 40 KHz.
[0017]
The filter medium 3 regenerated by washing overflows the separation tank 8 and settles in the washing tower 9. At this time, the filter medium 3 is distributed in contact with the chutes 5 a and 9 a arranged in multiple stages on the outer peripheral surface of the air lift pipe 5 and the inner peripheral surface of the cleaning tower 9, and is supplied to the upper surface of the filter medium layer 4. Then, the cleaning wastewater containing the light contaminants overflowing the separation tank 8 together with the filter medium 3 is discharged out of the tank together with the impurities from the cleaning discharge port 11. Even when a part of the filter medium 3 is mixed into the cleaning wastewater, the filter 11a is not discharged together with the cleaning wastewater by the filter 11a. In addition, the code | symbol 11b in a figure is an adjustment valve for adjusting the waste_water | drain amount of washing waste_water | drain.
[0018]
Further, the compressed air that rises in the air lift pipe together with the filter medium 3 accumulates in the upper part of the washing tower 9, and the liquid level in the washing tower 9 is pushed by the compressed air and gradually decreases. In order to exhaust the compressed air, the liquid level that is lowered is detected by a level meter 12 provided at the upper part of the cleaning tower 9, and when the liquid level reaches a set value or less of the level meter 12, an “open” signal is generated, The control valve 13a provided at the air exhaust port 13 at the top of the cleaning tower 9 is opened, and the compressed air accumulated at the top of the cleaning tower 9 is exhausted from the air exhaust port 13 to the atmosphere. When the liquid level rises again and reaches the set value of the level meter 12 or more, a “closed” signal is issued to close the control valve 13a. Reference numeral 15 denotes a drain port used when removing the filter medium 3 and the like.
[0019]
By using the thus configured filtration device 1, raw water containing impurities (suspension) is supplied from the supply port 7 into the filtration chamber 6 and descends the filter medium layer 4. During this time, the suspended matter is captured by the diatomaceous earth 3a, and the filtrate (treated water) passes through the treated water outlet 14f provided at the lower part of the filtration tank 2 and is discharged from the treated water outlet 14 to the outside. On the other hand, the contaminated diatomaceous earth 3a at the bottom of the filter medium layer 4 is transferred to the upper separation tank 8 while supplying the compressed air to the air lift pipe 5 and stirring the air lift pipe 5 together with the treated water below the filtration tank 2. During this time, impurities adhering to the surface of the diatomaceous earth 3a particles are peeled off. The suspension trapped in the porous portion of the diatomaceous earth 3a particles is peeled off by ultrasonic vibration of an ultrasonic cleaner 10a provided in the separation tank 8. The peeled light impurities (suspension) are discharged together with the treated water that has risen together as cleaning wastewater, and discharged from the cleaning outlet 11 to the outside of the tank. The washed and regenerated diatomaceous earth 3a settles in the cleaning tower 9, It is distributed by the chutes 5 a and 9 a and supplied to the upper surface of the filter medium layer 4.
[0020]
Although the particle diameter of the diatomaceous earth 3a described above is about 0.1 to 2.0 mm, the particle diameter of the filter medium (0.6 to 1.2 mm) of the conventional upward flow moving bed type filter using sand is used. If only diatomaceous earth 3a having a smaller particle size (about 0.5 mm or less) is used, further precise clarification filtration can be performed. Moreover, by using the diatomaceous earth 3a having only a small particle diameter, the angle of repose is reduced, the inclination of the conical portion at the bottom of the filtration tank 2 can be loosened, the height of the filtration tank 2 is lowered, and the total height of the filtration device 1 Also lower.
[0021]
FIG. 2 is a longitudinal sectional view schematically showing another embodiment of the filtration device 1 according to the present invention. Since the filtration tank 2 and the washing tower 9 in FIG. 2 are open type, the raw water is not press-fitted and the water column L (height from the upper surface of the filter medium layer 4 to the supply port 7) is used as a filtration force. The total height of 1 is higher than that of the closed type shown in FIG. However, an exhaust device for compressed air discharged from the upper portion of the air lift pipe 5 is not required, and the initial cost can be reduced. The filtration method is the same as that of the hermetic type of FIG.
[0022]
【The invention's effect】
Since the moving filter bed filtration device according to the present invention uses diatomaceous earth particles having a porous filter medium, compared to the upward flow filter bed filtration device using sand particles as a filter material conventionally used. Fine colloidal suspended solids that could not be captured by the conventional moving filter type filtration device can also be captured by the porous diatomaceous earth, and more precise microfiltration can be performed. In the cleaning of the filter medium, the contaminated filter medium is trapped in the porous diatomaceous earth by two-stage cleaning of stirring, cleaning and ultrasonic vibration performed in the separation tank while being transferred by the air lift pipe. Even fine suspended solids can be peeled off, and diatomaceous earth that has been completely washed and regenerated is returned to the upper surface of the filter medium layer, so that continuous and stable clarification filtration can be performed.
[0023]
If the filtration tank is hermetically sealed, the raw water can be press-fitted and supplied, so the overall height of the filtration device can be lowered, and the initial cost of buildings and the like can be reduced. And by using diatomaceous earth with only a small particle diameter, it is possible to perform fine microfiltration corresponding to precoat filtration or microfiltration membrane. Moreover, since the angle of repose becomes small and the inclination of the conical part at the lower part of the filtration tank can be loosened, the overall height of the filtration device is further lowered.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view schematically showing a moving filter bed type filtration apparatus according to the present invention.
FIG. 2 is a longitudinal sectional view schematically showing another embodiment of the moving filter bed type filtration apparatus according to the present invention.
FIG. 3 is a longitudinal sectional view schematically showing a conventional upward flow moving filter type filtration apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Filtration apparatus 2 Filtration tank 3 Filter medium 3a Diatomaceous earth 4 Filter medium layer 5 Air lift pipe 6 Filtration chamber 7 Supply port 8 Separation tank 9 Washing tower 10 Washing apparatus 10a Ultrasonic cleaner 11 Washing discharge port 11a, 14e Filter 12 Level meter 13 Air exhaust Port 13a Control valve 14 Treated water outlet 14a Treated water outlet pipe 14b Header pipe 14c Outlet pipe 14d Distributing umbrella

Claims (6)

  A filter medium (4) is formed by laminating a granular filter medium (3) heavier than water inside the filter tank (2), and is opened at the lower part of the filter medium layer (4) and the upper part of the filter tank (2). The filter medium (3) is pulled out from the bottom of the filter medium layer (4) by compressed air and transferred upward, and the filter medium (3) is washed and regenerated to circulate to the upper part of the filter medium layer (4). In the filtration device (1) erected with the pipe (5), the filtration tank (2) is formed in a closed type, and diatomaceous earth (3a) is used as the filter medium (3) to be loaded in the filtration tank (2). The raw water is press-fitted from the raw water supply port (7) provided in the filtration chamber (6) above the filter medium layer (4) to lower the filter medium layer (4), and the treated water is supplied to the filter tank (2). ) A moving filter bed type filtering device characterized in that it is taken out from the lower part.   A separation tank (8) is disposed on the outer periphery of the upper end opening of the air lift pipe (5) erected in the filtration tank (2), and the filtration tank is inserted from the filtration chamber (6) of the filtration tank (2). A washing tower (9) protruding above the top plate of (2) and surrounding the separation tank (8) is erected, and a washing device (10) for the filter medium (3) from the top of the washing tower (9) The lower end of the cleaning device (10) extends into the separation tank (8), and the cleaning outlet (11) of the filter medium (3) is provided on the upper side of the cleaning tower (9). The moving filter bed filtration according to claim 1, wherein the filtration tank (2), the washing tower (9), the air lift pipe (5), and the washing device (10) are arranged substantially concentrically. apparatus.   The moving filter bed type filtration device according to claim 2, wherein an ultrasonic cleaner (10a) is used as the cleaning device (10) for the filter medium (3). An air exhaust level meter (12) and an air exhaust port (13) are provided in the upper part of the washing tower (9), and the air exhaust port (13) is opened and closed in conjunction with the level meter (12). The moving filter bed type filtration device according to claim 1 or 2, further comprising a control valve (13a). The treated water outlet (14) provided at the lower part of the filtration tank (2) is provided with a loop-shaped header pipe (14b) connected to the treated water outlet pipe (14a) and the header pipe (14b). A plurality of outflow pipes (14c) provided, and a loop-shaped distribution umbrella (14d) provided above the outflow pipe (14c) and equally distributing treated water flowing into the outflow pipe (14c) The moving filter bed type filtration apparatus according to claim 1 or 2 , wherein the apparatus is configured. Claims, characterized in that the stretched and the lower surface portion, the washing tower (9) and the cleaning outlet (11) filter for filtration media erosion prevention to the opening of the (11a, 14e) of the distribution bevel (14d) Item 6. The moving filter type filtration device according to Item 5 .

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