JPH11123304A - High speed fiber filter for recharge method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove suspended fine particles causing clogging effectively by forming the lower half of a cylinder in the shape of a funnel to taper the thick lower part of a filter layer. SOLUTION: The lower half of a cylinder 5a is formed in the shape of a funnel to taper the lower part of a filter layer 5b. Although a compressive fiber filter material is used, since the lower half of a filtration tank cylinder is funnel-shaped, a filter which increases the flow velocity of the filtrate of the funnel-shaped part, makes the filter medium compact, and can catch fine particles is formed automatically. The filter layer in which compactness is different between the upper part and the lower part is formed, suspended particles of different particle sizes are caught by different layers, and clogging around a condensate well can be prevented. During the air backwashing of the filter medium, it can be washed uniformly without generating a local circulation area of the medium, the filter medium particles is diffused in the circumferential wall direction by upwash from the lower end of the funnel, and agitation is done efficiently. The height of a filtration tank necessary for agitation washing is can be made low, the effective filter layer can be made thick in the limited height, and fine particle catching performance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed fiber filtration device used in a recharge method.

[0002]

2. Description of the Related Art Large-scale underground construction requires pumping of a large amount of groundwater, and the pumping of groundwater has a problem on the surrounding ground environment. The construction method (condensation method) has come to be used. That is, as shown in FIG. 5, the recharging method uses a pumping well 1 for pumping groundwater.
The groundwater is pumped up into the chamber 2 by the pump P, and the groundwater is returned from the condensing well 4 through the high-speed filtration device 3.

The above-mentioned high-speed filtration device 3 is shown in detail in FIG. That is, φ = 6 to 10 in the cylinder 3a having a constant diameter.
mm, a fiber filter medium 3b formed to a length of 10 to 20 mm
It is filled with a layer thickness of m to 2 m. FIG. 7 shows the results of the treatment effect of the aquarium experiment when 10 ppm of kaolin was used as the raw water.

It can be seen that the SS removal rate increases as the thickness of the filter layer increases. Note that the particle size distribution of the raw water kaolin 10 ppm is as shown in FIG.

[0005]

However, in the recharging method using the high-speed filtration device 3 of the above-mentioned current model, the condensing function around the condensing well 4 is continuously reduced. A difficult question arises. The main cause of this clogging is fine suspended particles contained in the pumped water. The particle size distribution of the filtered water of the current model is shown in FIG. 4 described above. It is apparent that particles having a particle size of 5 μm or less could not be removed to a certain extent, indicating that the above-mentioned various problems have been caused by the characteristics of the current type.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a high-speed fiber filtration device capable of effectively removing fine suspended particles that cause clogging. Is to do.

[0007]

Means for Solving the Problems To achieve the above object, a high-speed fiber filtration device according to the present invention is characterized in that the lower half of the cylindrical body is formed in a funnel shape so that the lower part of the filter layer gradually becomes smaller in diameter. is there.

[0008]

In the filtering apparatus of the present invention, a compressible fiber filter medium having a diameter of about 6 to 10 mm and a length of about 10 to 20 mm is used as the filter medium of the conventional type. By having a funnel shape, the flow rate of the filtered water in that part is increased, and the filter medium is compacted, so that fine particles can be captured (an increase in the flow rate does not cause a reduction in the removal rate). Here, since the filter layers having different consolidation states can be formed in the upper and lower portions, suspended particles having different particle sizes can be captured by layer (large particles are captured in the upper portion and small particles are captured in the lower portion).

[0009] As described above, a filter having a small particle size capturing capability of a filter layer in which a compressible filter medium is newly compacted in the lower half can be automatically formed. Since the suspended particles can be captured, clogging around the condensate well can be prevented.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. In the device 5 of the present invention, the lower half of the cylindrical body 5a is formed in a funnel shape so that the lower part of the filter layer 5b is gradually reduced in diameter. FIG. 2 shows the SS removal rate of the device 5 of the present invention in which a new consolidation layer is formed below the filter layer 5b.

The removal rate is greatly improved as compared with the conventional type shown in FIG. Further, looking at the particle size distribution of the filtered water of the improved model of the present invention shown in FIG.
Particles of m or more could be removed to some extent, but particles of 5 μm or less could not be removed much, but in the type of the present invention, particles of 5 μm or less could be removed beyond the measurement limit. I understand.

Thus, clogging around the condensing well can be reliably prevented. However, the device of the present invention has other advantageous effects other than those described above. That is, as shown in FIG. 3, in the case of the conventional type (a), when the filter medium is backwashed by air, local circulation areas 6 and 6 of the filter medium are generated due to the cylindrical body 3a having a constant diameter. Although uniform washing can be prevented, in the improved type (b) of the present invention, a force 7 for diffusing the filter medium particles in the peripheral wall direction by blowing up from the lower end of the funnel acts, and stirring can be performed effectively.

For this reason, it is necessary for stirring cleaning.
The height of the filtration tank can be kept low. As a result, in the present invention, an ideal convenience can be expected in which the effective filtration layer can be thickened within the limited height and the performance of capturing fine particles can be improved.

[0014]

As described above, the apparatus of the present invention is constituted, so that clogging around the condensate well in the recharging method can be eliminated.

[Brief description of the drawings]

FIG. 1 is an overall explanatory view of the device of the present invention.

FIG. 2 is a graph showing the removal rate of the apparatus of the present invention.

3 (a) and 3 (b) are explanatory views of a conventional type and an improved type apparatus according to the present invention in which a filter medium particle is blown up during backwashing with air. FIG.

FIG. 4 is a particle size distribution graph of raw water, filtered water of the current model, and filtered water of the improved model of the present invention.

FIG. 5 is an explanatory view of a recharge method.

FIG. 6 is an explanatory view of a conventional type filtration tank.

FIG. 7 is a graph showing the SS removal capability of a conventional type filtration tank.

[Explanation of symbols]

 Reference Signs List 1 pumping well 2 chamber 3 high-speed filtration device 3a cylinder 3b fiber filter medium 4 condensing well 5 device 5a cylinder 5b filtration layer 6 local circulation area 7 power to diffuse

Claims (1)

[Claims] 1. A high-speed fiber filtration device for use in a recharging method, wherein a lower half of a cylindrical body is formed in a funnel shape so that a lower portion of a filter layer gradually becomes smaller in diameter.