JP2000064365A - Sand-inflow preventive screen device for deep well - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sand-inflow preventive screen device for a deep well, by which the deep well can be used for a prolonged term by quick corresponding when clogging is generated. SOLUTION: In a casing pipe 1, in which a large number of holes communicated with internal and external surfaces are disposed in rows in the vertical direction on a peripheral surface, the casing pipe 1 is composed of an external cylinder 1a and an internal cylinder 1b. Screens 4 preventing the intrusion of sand, etc., mixed with water flowed in from the outside is inserted into arcuate voids 3 in a plan view formed by column materials 2 holding a section between both cylinders 1a, 1b at regular intervals in an exchangeable manner in the vertical direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deep well sand inflow prevention screen device for preventing adhesion of sand or the like flowing into a strainer (water collection hole) provided in a casing pipe in a deep well.

[0002]

2. Description of the Related Art Generally, in areas where tap water has not been used as domestic water, the diameter is generally 200 to 400 mm,
Groundwater is taken from deep wells with a facility depth of 50 to 300 m. In this case, the groundwater intake is mainly the groundwater under pressure in the aquifer, but the deeper aquifers are alternating layers (impermeable layers, aquifers, impermeable layers, aquifers, etc.). It is a continuous formation, and the sand present in the gravel layer is relatively fine particles.

As the conventional form of the casing pipe (pumping pipe) for pumping the groundwater under pressure, for example, the types shown in FIGS. 5 to 7 are generally widely used.

That is, FIG. 5 is a cross-sectional view of a casing pipe (pumping pipe) a in which a large number of horizontal strainers b (water collecting holes) are arranged vertically, and FIG. 6 shows a casing pipe (pumping pipe) c. In the broken perspective view, a slit-shaped strainer d having an appropriate length in the vertical direction, which is obtained by equally dividing the circumference.
(Water collecting holes) arranged in a zigzag pattern, and FIG. 7 is a broken perspective view of a casing pipe (pumping pipe) e. The strainers f (water collection holes) are made up of staggered arrangement.

Strainers (water collection holes) used for these casing pipes (pumping pipes) are constructed by burying the casing pipes at appropriate depths at respective positions where a plurality of aquifers are present. Since the groundwater inside flows into the casing pipe through the strainer, it is used by pumping the water in the casing pipe with a water pump or the like.

[0006]

However, in these pumps, fine particles of sand or the like also flow into the casing pipe together with the water, and as a result, the sand is pumped together with the water, so that the sand accumulates in the water storage tank. In addition to sand, the strainer may become clogged with foreign matter such as wear of the submersible pump for pumping water, corrosion of the casing pipe, and depression of the well surroundings. Had problems such as not functioning as a well.

As a result of examining the cause of the inflow of sand, in addition to the holes of the strainer being opened larger than the sand particles, the area of the strainer is insufficient with respect to the amount of pumped water. As the water level increases, the water level in the well increases and the inflow velocity becomes the permeability coefficient (velocity in the aquifer).
As a result, sand is deposited around the well along with water and flows into the well.

[0008]

In order to solve the above problems, the present invention aims to increase the area of the strainer, and when clogging occurs, it is possible to quickly respond to the problem. The object of the present invention is to provide a sand inflow prevention screen device for deep wells that can be used for a long period of time.As a solution to this problem, a screen device is installed in the strainer when the screen device is clogged. Can be exchanged.

That is, according to the present invention, in a deep well casing pipe in which a large number of holes communicating with the inner and outer peripheral surfaces are vertically arranged, the casing pipe is composed of an outer cylinder and an inner cylinder, and the space between both cylinders is formed. A screen that prevents the entry of sand mixed with water flowing in from the outside into the space formed by the pillars that are held at regular equal intervals and that is arcuate in plan view is replaceably inserted in the vertical direction. It is characterized by having done.

If water stains or sand adhere to the screen and the water permeability deteriorates, the screen can be easily taken out from the void and washed, or a new screen can be replaced. Therefore, the water level in the casing can be prevented from dropping.

Further, it is preferable that the screen is constituted by vertically connecting a plurality of filter media fixed by a vertical rail and a horizontal rail by a connecting portion. This ensures that the screen is rigidly fixed and does not come off during use.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 1 is a plan view of a sand inflow prevention screen device for a deep well according to the present invention. A casing pipe 1 is composed of an outer cylinder 1a and an inner cylinder 1b.
Column members 2 (four in FIG. 1) are fixed between b to maintain a constant interval between them.
The arc-shaped portion in plan view formed by the column members 2 adjacent to each other and the adjacent column members 2 is a void 3 extending downward. A screen 4 is vertically replaceably inserted into the void 3 from above. It should be noted that the screen 4 is sized so as to have a margin between the screen 3 and the space 3 so that the screen 4 can be easily inserted.

FIG. 2 is a perspective view of the casing pipe 1 shown in FIG. 1 with the outer appearance broken away. The outer cylinder 1a and the inner cylinder 1b are shown.
A large number of holes 1c (or vertical slits 1d instead of the holes) communicating vertically and horizontally to the inner and outer surfaces are provided on the peripheral surface of the screen as in the conventional case. The area of the water-permeable holes as a strainer is increased by communicating with the strainer.

The screen 4 is inserted as shown in FIG. 2, and FIG. 3 is a front view of the detailed structure thereof, and FIG. 4 shows the filter medium 5 alone.

That is, the filter material 5 is made of water-permeable paper, ceramic fiber material, nylon fiber material, or the like, and has a thickness of about 5 mm, has good water permeability, and has a square shape of an appropriate size which is extremely dense. It is a curtain.

For example, as shown in FIG. 3, the filter medium 5 itself has its periphery fixed by vertical bars 6 and horizontal bars 7 of a predetermined size so as not to fall off, and is connected by a connecting portion 8 in the upper and lower directions. The screen 4 has an appropriate length.

Next, the operation will be described.

In the case of a new deep well, after completion of excavation of the well, the casing pipe 1 consisting of the outer cylinder 1a, the inner cylinder 1b and the pillar material 2 is lowered to a predetermined depth and installed, and after cleaning the inside, it is shown in FIG. As shown, the individually assembled screens 4 are attached by inserting the screens 4 into the state shown in FIG.

Regarding the insertion of the screen 4, since the water pressure increases as the depth of the deep well increases, the inner cylinder 1b having a large number of holes 1c inside the screen 4 is tied together or set as shown in FIG. You may make it insert in the inside of the inner cylinder 1b of the casing pipe 1.

When the filter medium 5 itself of the screen 4 becomes poor in water permeability due to the adhesion of water stain during use, the screen 4 is removed from the void 3 in a short time for cleaning.
The screen 4 is inserted again after cleaning, but the insertion may be replaced with a new screen 4 if necessary.

Since the water permeation area is increased by providing such a device, there is no fear that the water level in the casing pipe will drop due to the accumulation of sand that has flowed in together with water or the clogging of the water collection holes as in the conventional case. Will be done.

[0023]

The present invention, which is configured as described above, has the following effects.

1) According to claim 1, when water stains or sand adhere to the screen and the water permeability becomes poor, the screen can be easily removed from the void and washed, or replaced with a new screen. Since it is possible to prevent the water level from dropping inside the casing pipe, it is possible to use the deep well for a long period of time.

2) According to claim 2, since the screen is vertically connected by the connecting portion of the filter medium fixed by the vertical crosspiece or the horizontal crosspiece, it is firmly fixed and there is no problem that the screen comes off from the crosspiece during use. Does not happen.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a casing pipe according to the present invention.

FIG. 2 is a perspective view in which a part of the casing pipe of FIG. 1 is cut away.

FIG. 3 is a plan view showing details of a screen portion of FIG.

FIG. 4 is a detailed view showing the filter medium alone of FIG.

FIG. 5 is a sectional view showing an example of a structure of a conventional casing pipe.

FIG. 6 is a broken perspective view showing another example of the structure of a conventional casing pipe.

FIG. 7 is a broken perspective view showing another example of the structure of a conventional casing pipe.

[Explanation of symbols]

1 Casing pipe 1a Outer cylinder 1b inner cylinder 1c hole 1d slit 2 pillar materials 3 vacant places 4 screen 5 filter media 6 vertical bars 7 side rail 8 joints

Claims (2)

[Claims] 1. A casing pipe for a deep well in which a large number of holes communicating with the inner and outer surfaces of the peripheral surface are vertically arranged in a row, the casing pipe being composed of an outer cylinder and an inner cylinder, and a constant distance between both cylinders. A screen that prevents the entry of sand mixed with water flowing in from the outside into the space formed by the pillars that are held at equal intervals and that is arcuate in plan view is replaceable vertically. A screen device for preventing sand inflow for deep wells. 2. The sand inflow prevention screen device for a deep well according to claim 1, wherein said screen is constituted by vertically connecting a plurality of filter media fixed by vertical rails and horizontal rails by connecting portions.