JPH10174805A - Air dispersing pipe for air-cleaned filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly disperse and discharge air by inserting one end of a short pipe into an air dispersing pipe, extending the other end of the short pipe into a perforated block and releasing the pressure into the block from the other end of the short pipe. SOLUTION: One end of a short pipe 22 is inserted into an air dispersing pipe 19, and the other end of the short pipe 22 is extended close to the apex of the inner shell 11 of the block 8 having an inverted V-shaped section. When pressure air is introduced into the air discharge pipe 19, the water level in the pipe 19 is lowered by the air pressure to the end of the short pipe, and the pressure air flows into the short pipe 22 and ascends in the short pipe 22 to the block 8. Consequently, the water level is lowered to the orifice of the inner shell 11 without troubling the water surface in the block 8, and the pressure air is discharged from the orifice. Since the compressed air is uniformly discharged from the orifice of the outer shell 10 in this way, almost the entire filter bed is excellently cleaned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air dispersion device attached to a filtration device for filtering water in a wide range of fields, such as domestic wastewater, food wastewater, chemical / pharmaceutical wastewater, landfill leachate, tap water, service water, and seawater. About pipes.

[0002]

2. Description of the Related Art Conventionally, a filter layer is formed by supporting a granular medium such as gravel, sand, activated carbon and a plastic filter medium in a circular or rectangular filter tank with a support material. 2. Description of the Related Art There is known a filtering apparatus characterized in that raw water is supplied from an upper part or a lower part of a filtration tank and is supplied in a downward flow or an upward flow to filter pollutants in the raw water by using a filtering action. For example, as shown in FIG.
The filtration device 1 includes a filtration tank 3 having a raw water supply port 2 at the top.
At the lowermost part of the inside, a water / water distribution device 4 for evenly distributing the cleaning air and collecting and distributing treated water and backwash water is installed, and a support layer 5 of several layers of gravel is provided on the upper part of the water / water distribution device 4. To form a filter layer 6 filled with a filter medium, and a drainage pipe 7 and a backwash drainage trough 8 are provided in the upper free board so that washing wastewater containing a large amount of suspended matter is efficiently discharged. In the case of raw water with a large amount of suspended matter, an intermediate washing pipe 9 is provided slightly above the middle part of the filter layer to perform intermediate washing of the upper part of the filter layer 6 while passing water.

[0003] The type of filter medium and the particle size of the filter medium forming the filter layer 6 are properly used depending on the purpose of processing.

The air / water distribution device 4 has a function of uniformly distributing diffused air and collecting treated water when passing water, and evenly dispersing cleaning air and backwash water during backwashing. The water distribution device is a so-called “perforated block”
0-13724) are combined in parallel.

FIG. 3 is a sectional view of the perforated block B. The perforated block B has an outer shell 10 having a rectangular cross section, and an inner shell 11 having a substantially inverted V-shaped cross section disposed inside the outer shell 10, and a central passage 12 and side passages 13 provided on both sides of the central passage 12. A plurality of orifices 1 are provided on the upper surface of the outer shell 10 in communication with the side passages 13.
4 are formed, and the inner shell 11 is provided with cleaning air orifice groups 15 and 16 and a water flow orifice group 17 in a direction perpendicular to the paper surface so as to communicate with the central passage 12 and the side passages 13 so as to be provided at the time of water passage and backwash. Even if the amount of air or water changes, care is taken to maintain uniformity by the internal equal pressure chamber 18.

[0006] In the above-described filtration apparatus, washing is appropriately performed in order to effectively perform filtration and extend the life of the filter medium. As this cleaning method, the following method is performed. That is, when the pressurized air is introduced into the air dispersion pipe 19 shown in FIG. 3 and the water pressure in the pipe 19 is gradually depressed by this air pressure and the water in the pipe 19 is removed to the outside, the pressure air in the pipe 19 is gradually reduced. Is discharged from the small hole 20 at the bottom of this pipe and reaches the perforated block at the top. Then, similarly, the water in the perforated block is pushed down by air pressure, and when the water level in the perforated block falls to the height of the orifice group 15, the pressurized air flows from the orifice group 15 to the upper filter layer (FIG. Further, when the water level in the perforated block falls to the level of the orifice group 16, pressurized air is also discharged from the orifice group. The suspended solids that have accumulated on the surface of the filter medium forming the filter are removed by being peeled off, and then these suspended solids are discharged to the outside together with the backwash water that flows into the filter layer from the bottom of the perforated block. Thus, the surface of the filter medium is restored to a state close to the initial state, and the target water can be continuously filtered.

However, the bubbles 21 discharged one after another from the small holes 20 at the bottom of the pipe 19 rise in an unspecified direction.
Due to the influence of the bubbles, the water surface W in the perforated block undulates, and due to the undulations, the discharge of the pressurized air from the orifice group 15 may be interrupted or the pressurized air may be discharged at irregular timing. Further, the water level in the perforated block B in the direction perpendicular to the paper surface is not constant, and may undulate. As a result, the pressure air discharged from the perforated block is not uniform in the direction perpendicular to the plane of the paper, a relatively large amount of air is discharged from a specific orifice, and a small amount of air is discharged from some orifices. Occurs, which results in defective washing of the filter layer. Furthermore, at the time of air-water cleaning in which air and water are simultaneously flown, bubbles 21 discharged from the small holes 20 are entrained by the water flow of the cleaning water and do not enter the predetermined perforated block but enter another perforated block. As a result, The supply amount of air for each perforated block becomes non-uniform, which causes further poor cleaning of the filter layer.

Further, in this system, since the position of the small hole 20 at the bottom of the pipe 19 is the deepest portion, the water pressure becomes high and a pressure air blower having a relatively large head is required.

As in the present invention, a J-tube system (see FIG. 4)
However, in the J-tube method, water in the J-tube may not be discharged due to difficulties in manufacturing accuracy and mounting accuracy. As a result, the air cannot be evenly fed into the multi-row V-grooves.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a low-cost air-cleaning filter having a function of uniformly dispersing and releasing air. An object of the present invention is to provide an air distribution pipe.

[0011]

In order to achieve the above-mentioned object, the present invention comprises inserting one end of a short pipe into an air distribution pipe, and allowing the other end of the short pipe to reach a perforated block. Since the pressure air is discharged into the perforated block from the other end of the pipe, no waving occurs in the perforated block, and the water level in the perforated block is flat and the water level is uniform. descend. As a result, compressed air is almost uniformly released from any part of the orifice group on the top of the perforated block,
The washing is carried out satisfactorily over almost the entire volume of the filter layer, and no defective washing occurs. In addition, at the time of air water washing,
Since it is not affected by the flow of the washing water, the air supply amount for each perforated block is constant, and the washing is performed well.

[0012]

DETAILED DESCRIPTION OF THE INVENTION That is, the present invention is installed at a lower part of the above-mentioned filtration tank in a filtration apparatus in which raw water flows through a filtration tank having a filtration layer filled with a granular medium in a downward flow or an upward flow. In the air dispersion pipe for an air-washing filter provided immediately below a perforated block, the perforated block forms an outer shell, a central passage in the outer shell, and side passages on both sides of the central passage. An inner shell having a substantially inverted V-shaped cross-section disposed in the outer shell, further having at least one orifice communicating with both side passages at an upper portion of the outer shell, and a central passage and a side at an upper portion of the inner shell; At least one communicating with the external passage
One orifice is provided, and one end of a short pipe is inserted into the air distribution pipe so as to be orthogonal to the longitudinal direction of the air distribution pipe, and the other end of the short pipe is inverted V-shaped cross section in the perforated block. The first invention is an air dispersion tube for an air-washing filter characterized by reaching the vicinity of the top of the inner shell of the first invention.In the first invention, a small hole is provided at an upper portion of a short pipe in the air dispersion tube. A second aspect of the present invention is an air dispersion pipe for an air-washing type filtration device, which is provided.

According to the air dispersion pipe for an air-washing filter configured as described above, when pressurized air is introduced into the air dispersion pipe, the water pressure in the air dispersion pipe drops due to this air pressure, and the end of the short pipe is reduced. When the water level drops to the position, the pressurized air flows into the short pipe and rises in the short pipe to reach the perforated block. Then, when the water level is lowered without making the water surface in the perforated block undulate, and the water level is lowered to the orifice portion of the inner shell, the pressurized air is discharged from the orifice. In this way, the pressurized air is almost uniformly discharged from any part of the orifice group of the outer shell, so that good washing is performed over almost the entire volume of the filter layer. Also,
Since a short pipe can be inserted for each block of a plurality of perforated blocks arranged in parallel, the air supply amount for each perforated block is constant, and cleaning is performed well.

[0014]

Embodiments of the present invention will be described below. In FIG. 1, one end of a short pipe 22 is inserted into an air distribution pipe 19,
The other end of the short pipe 22 reaches near the top of the inner shell 11 having an inverted V-shaped cross section of the upper perforated block (I-tube method).
Further, a small hole 23 is provided above the short pipe 22 in the air dispersion pipe 19.
Is provided. By providing such a small hole 23, until the decrease in the level of one end E ₁ of the water level short pipe 22 in the dispersion pipes 19, flows from the small holes 23 in the pressure air inside the short tube 22, airlift The effect can be expected to have the effect of shortening the air cleaning start time.

Next, a comparative test of the dispersibility of the released air and the time from the start of work to the start of air washing due to the difference in the type of air dispersion pipe was performed using an actual filtration device of an actual water purification plant. The results are set forth in Table 1 below.

[0016]

[Table 1]

As is clear from Table 1, this embodiment has a good dispersibility of the released air, a short time until the start of air cleaning, and a small power consumption. However, the “J tube method” (see FIG. 4) has a slightly poor dispersibility of the released air.
Long time to start air cleaning, high power consumption. This is because, as shown in FIG. 4, in the J-tube method, since the horizontal portion H exists, the horizontal portion hinders the uniform discharge of the pressurized air. The pressurized air is released, but only a small amount of pressurized air may be released from another J-tube. As a result, the dispersibility of the released air is poor, and the time until the start of air cleaning is prolonged. Also, from the horizontal portion H to the upper end E of the J tube
_Since the length up to ₂ is long (the head is large), it seems that power consumption has also increased.

Further, the perforated tube method (see FIG. 3) has the above-mentioned disadvantages, so that the dispersibility of the released air is poor, the time until the start of air cleaning is long, and the power consumption is low, as in the "J tube method". There are many.

The present invention can be applied to a biological membrane filtration device, an activated carbon adsorption device, and the like, in which organisms are attached to a filter medium, which are used for removing soluble organic substances, in addition to the above embodiment. They are appropriately selected depending on the quality of the raw water, and whether or not the water is passed in a downward flow or an upward flow is also appropriately selected.

[0020]

Since the present invention is constructed as described above, the discharged air is evenly dispersed, the time to start air cleaning is short, the power consumption is small, and the shape is simple. It is possible to provide an air dispersion tube for an air washing type filtration device.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a configuration of an air distribution pipe (I-tube method) and a perforated block of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a general filtration device.

FIG. 3 (a) is a conventional air dispersion pipe (perforated pipe method).
And FIG. 3B is a cross-sectional view of the air distribution tube.

FIG. 4 is an enlarged cross-sectional view showing a configuration of a conventional air distribution pipe (J-tube type) and a perforated block.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Filtration apparatus 3 ... Filtration tank 4 ... Air-water distribution apparatus 6 ... Filter layer 10 ... Outer shell 11 ... Inner shell 12 ... Central passage 13 ... Side passage 14 ... Orifice 15, 16 ... Cleaning air orifice group 17 ... Communication Water orifice group 19 ... air dispersion pipe 22 ... short pipe 23 ... small hole B ... perforated block

Claims (2)

[Claims] 1. A filter device having a filtration layer having a filter layer filled with a granular medium and having raw water flow therethrough in a downward flow or an upward flow, provided directly below a perforated block provided at a lower portion of the filtration tank. In the air dispersion pipe for an air-washing filter, the perforated block is disposed in the outer shell so as to form an outer shell, a central passage in the outer shell, and side passages on both sides of the central passage. An inner shell having an inverted V-shaped cross-section, and further comprising at least one orifice communicating with both side passages at an upper portion of the outer shell, and at least one orifice communicating a central passage and a side passage with an upper portion of the inner shell. One orifice is provided, and one end of a short pipe is inserted into the air distribution pipe so as to be orthogonal to the longitudinal direction of the air distribution pipe, and the other end of the short pipe is inverted V-shaped cross section in the perforated block. Characterized by reaching near the top of the inner shell Dispersion pipe for air-cleaning filtration device. 2. The air dispersion tube according to claim 1, wherein a small hole is provided at an upper portion of the short tube in the air dispersion tube.