JP4476972B2 - Water collecting pipe for well - Google Patents

Description

  The present invention belongs to the field of water collecting pipes for wells that store groundwater therein, and particularly relates to water collecting pipes for wells that can suppress a decrease in the amount of storage due to pumping by improving the water collecting function.

  Conventionally, a method of installing a well has been used as one of the utilization methods of groundwater. The general structure of this well is to search for aquifers in the soil rich in groundwater and to drill, and then casing the periphery of the borehole with a member that can pass water, or pass through the borehole. A water collecting pipe or a water intake pipe having a water inlet on the side surface was disposed.

  Such a water collecting pipe 9 is mainly configured as shown in FIG. In other words, it is a pipe that is buried in the ground in a standing manner and the lower side reaches the aquifer L, and in particular, a water passage 91 that allows groundwater to flow on the side surface on the lower side is established. It has a bottomed configuration. The groundwater W stored inside the water collecting pipe 9 was pumped by the pumping pump 7 through the pumping pipe 71 arranged inside the pipe as necessary.

  Further, as an improvement in the water collecting function, for example, Patent Document 1 includes a plurality of intake pipes having a plurality of perforations formed in a horizontal radial shape with a small diameter from a trunk portion of a well pipe buried in the ground. The thing of the structure to set is disclosed. In particular, this intake pipe is characterized in that an injection nozzle that discharges high-pressure air or the like is provided to prevent washing around the intake pipe and clogging.

The water collecting pipe disclosed in Patent Document 2 is formed as a cylindrical body by connecting two ring bodies with a core material arranged along a circumference, and a wire rod is attached to the outer periphery of the cylindrical body with a slight gap. An outer tube is formed by spirally winding, an inner tube having the same configuration having a smaller diameter is disposed in the outer tube, and gravel is filled between the outer tube and the inner tube.
JP 2000-96634 A (second page, FIG. 1) JP-A-8-158418 (page 3-5, Fig. 1)

  However, since the well in which the intake pipe of Patent Document 1 is arranged has a configuration in which a plurality of intake pipes are arranged in a horizontal and radial direction around the well of the well buried underground, excavation around the well is necessary for the installation. Furthermore, since the structure is complicated, there is a problem that initial cost for manufacturing and arrangement increases. Moreover, since the high-pressure pipe is arranged in the intake pipe and high-pressure air and high-pressure water are jetted to the necessary part, there is a problem that the running cost increases.

  The water collecting pipe of Patent Document 2 has a complicated configuration in which an inner pipe having the same structure is inserted into an outer pipe formed by winding a wire around, and gravel is filled in these gaps. The handling of the installation was also poor because of the weight of the unit length.

  SUMMARY OF THE INVENTION The present invention is intended to solve the above-described problems, and an object of the present invention is to provide a well water collecting pipe having a simple structure and improved water collecting function and handling for installation.

  In order to solve the above-described problems, a well water collecting pipe 1 according to the present invention (hereinafter abbreviated as “main water collecting pipe”) is configured as follows.

That is, the outer pipe (2) that has one or a plurality of water-permeable ports (23) on the side surface and is buried in an upright manner, and the outer pipe (2) is provided with a separation space (4). And an inner pipe (3) having one or a plurality of water inlets (32) on the side face and having an inside at atmospheric pressure, and an outer peripheral wall of the inner pipe (3) and the outer pipe ( The inner peripheral wall of 2) and the above-mentioned separation space (4) partitioned by sealing the upper end are reduced from the atmospheric pressure .
Note that a plurality of the inner pipes (3) can be arranged inside the outer pipe (2).

  A preferable configuration of the water collecting pipe (1) is that an inner pipe (3) having a smaller diameter than that of the outer pipe (2) is formed in the outer pipe (2) made of a steel pipe to form a coaxial double pipe structure. In addition, a net body (22) is provided around a part of the outer circumference of the outer pipe (2) to open a water-permeable port (23), and a plurality of water-flow holes ( 32) is opened radially and in multiple stages. In addition, the lower end of the outer pipe (2) and the inner pipe (3) are integrally sealed, and the opening position of the water inlet (32) of the inner pipe (3) is set near the lower end of the side surface. .

  Due to the above configuration, this water collecting pipe (1) temporarily stores groundwater (W) collected from the aquifer (L) in the space (4) formed by the outer pipe (2) and the inner pipe (3). If the amount of water stored in the inner pipe (3) is reduced due to pumping, the groundwater (W) stored in the separation space (4) appropriately through the water inlet (32) by the water pressure balancing action Will be replenished to the inner pipe (3).

  A more preferable configuration of the water collecting pipe (1) is to depressurize the separation space (4) formed by the outer pipe (2) and the inner pipe (3) from the atmospheric pressure by connecting, for example, a decompression pump (8). It is a configuration. During this depressurization or for a certain period of time after depressurization, the separation space (4) is in a so-called negative pressure state in which the pressure is reduced from the atmospheric pressure, so that the function of collecting groundwater (W) from the aquifer (L) is improved. Thus, it becomes possible to store a large amount of groundwater (W) in the separation space (4) in advance.

  In addition, the code | symbol with the parenthesis mentioned above is added with reference to drawing code | symbol in order to obtain an understanding of the structure of invention, and is not limited to the form on this drawing.

Since this water collection pipe is the above-mentioned composition, the following effects are produced.
That is, since it is a so-called coaxial double pipe (or multiple pipe) structure in which the inner pipe is arranged inside the outer pipe, even if the groundwater stored in the inner pipe is pumped up, the space between the outer pipe and the inner pipe is separated. The groundwater stored in advance flows into the inner pipe side through the water inlet by the balancing action of the water pressure difference, that is, it is replenished. This is because it is possible to suppress a decrease in the amount of storage due to pumping on the inner pipe side, and when the groundwater suddenly flows into the inner pipe side from the separated space, the upper end side of the separated space is sealed. The separation space becomes a slightly negative pressure state, and the water collecting function from the aquifer is also improved.

  Further, when the separation space is depressurized from the atmospheric pressure, the above-described negative pressure state becomes more prominent, so that the function of collecting water from the aquifer is further improved.

  In addition, the structure of this water collecting pipe is easy to manufacture because it is simple with a coaxial double pipe (or multiple pipe) structure of a steel pipe, and since the weight is not bulky, handling for installation is also simple. Demonstrates the effect of reducing initial costs.

Below, the example of the best embodiment of this water collection pipe | tube is demonstrated in detail based on drawing.
FIG. 1 is a partially cutaway perspective view showing the external appearance of the water collecting pipe, and FIG. 2 is a longitudinal sectional view showing the operation of the water collecting pipe.

  The water collecting pipe 1 includes an inner pipe 3 made of a steel pipe having a diameter smaller than that of the outer pipe 2 inside an outer pipe 2 in which a steel pipe having a predetermined diameter is embedded in the ground in an upright manner and the upper end portion is exposed on the ground surface G. Are arranged so as to have a coaxial double tube structure.

  Further, in the water collecting pipe 1, the outer peripheral wall of the inner pipe 3 is positioned with a predetermined separation distance from the inner peripheral wall of the outer pipe 2, thereby forming a separation space 4.

  Further, the upper end portion of the water collecting pipe 1 exposed on the ground is a sealed portion 5 in which the flange portions 21 and 31 whose diameters are expanded in the horizontal direction on the ground surface G are in a sealed state while forming a predetermined space in the vertical direction. Is forming. On the other hand, a bottom plate 6 having a size covering the entire lower end surface of the outer pipe 2 is disposed at the lower end of the main water collecting pipe 1, and the lower ends of both the outer pipe 2 and the inner pipe 3 are connected. However, they are sealed together.

  Due to the above configuration, the water collecting pipe 1 forms a closed space in which the separation space 4 and the sealing portion 5 are in communication. The sealing portion 5 can be connected to the decompression pump 8 disposed on the ground surface G via the decompression pipe 81, and can reduce the separation space 4 from the atmospheric pressure as necessary.

  The outer tube 2 is provided with a net 22 over the entire circumference of the side surface of the lower end thereof. By the arrangement of the net body 22, a plurality of water permeable ports 23 are opened on the side surface of the outer tube 2. The groundwater W of the aquifer L will permeate the separation space 4 inside the outer pipe 2 through the water passage 23. On the side surface of the lower end portion of the inner tube 3, a water passage 32 is formed by opening a plurality of holes radially and in multiple stages. The groundwater W stored in the separation space 4 flows into the inner pipe 3 through the water passage 32.

In addition, the opening position of the water permeable opening 23 of the outer tube 2 is not limited to the opening position of the present embodiment, and can be appropriately changed to a position adapted to the aquifer L. On the other hand, the opening position of the water inlet 32 of the inner pipe 3 is preferably near the lower end of the inner pipe 3 in order to obtain or promote the inflow of the groundwater W stored in the separation space 4.
[Action]

  The main water collecting pipe 1 having the above-described configuration is arranged in a standing state in the borehole that reaches the aquifer L searched in advance and the sealing portion 5 is exposed on the ground surface, and operates as follows. .

  The groundwater W of the aquifer L is permeated into the separation space 4 through the water permeation port 23 of the outer pipe 2 and stored (arrow a). Then, the groundwater W in the separation space 4 flows into the inner pipe 3 through the water passage 32 and is stored (arrow b). In this state, the ground water W stored in the separation space 4 and the inner pipe 3 has an action of balancing the water pressure, so that both liquid levels are substantially the same height and become stable.

  In the state where the liquid level is substantially the same, the pump 7 is operated, and the groundwater W stored in the inner pipe 3 is pumped through the pumping pipe 71 disposed therein. When the amount of groundwater W stored in the inner pipe 3 decreases due to this pumping, a difference in water pressure occurs between the groundwater W stored in the separation space 4. The groundwater W stored in the separation space 4 takes a certain time but has an effect of balancing the water pressure difference, and therefore flows into the inner pipe side through the water passage 32 (arrow b). In conjunction with this inflow action, the separation space 4 in which the amount of storage has decreased has the same action of balancing the water pressure difference as described above, and the negative pressure action by sealing the upper end portion. The groundwater W will permeate through the mouth 23 while taking a certain time (arrow a).

  Further, when the decompression pump 8 connected to the sealing portion 5 communicating with the separation space 4 is operated, the inside of the separation space 4 is depressurized from the atmospheric pressure to become a slight negative pressure state, The water collection function from the aquifer L is improved. Due to the improvement of the water collecting function, the storage amount of the ground water W in the separation space 4 increases, and the decrease in the storage amount of the ground water W in the inner pipe 3 can be supplemented without delay.

  By the way, when only the main pipe 1 and the outer pipe 2 having the same structure as the conventional water collection pipe are installed in the same aquifer L and the same amount of groundwater W is pumped and compared, the water level is 4% to An experimental result of about 8% was obtained. In other words, it was confirmed that the water collecting pipe 1 is more replenished from the separation space 4 and the aquifer L than the water collecting pipe 1 having the conventional structure even when the groundwater W of the inner pipe 3 is pumped up.

It is a partially cutaway perspective view showing the appearance of the water collecting pipe. It is a longitudinal cross-sectional view which shows the effect | action of this water collection pipe | tube. It is a longitudinal cross-sectional view which shows the outline of the water collecting pipe of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water collecting pipe 2 Outer pipe 21 Flange part 22 Net body 23 Water-permeable port 3 Inner pipe 31 Flange part 32 Water-passing port 4 Separation space 5 Sealing part 6 Bottom plate 7 Pumping pump 71 Pumping pipe 8 Pressure reducing pump 81 Pressure reducing pipe 9 Water collecting pipe ( (Conventional example)
91 Waterway G Ground surface L Aquifer W Groundwater

Claims (5)

An outer pipe (2) which has one or a plurality of water-permeable openings (23) on the side surface and is buried underground in a standing manner ;
An inner pipe (3) that is arranged with a separation space (4) inside the outer pipe (2) and that has one or more water inlets (32) on the side face and has the inside at atmospheric pressure ;
Consisting of
A well characterized in that the outer peripheral wall of the inner pipe (3), the inner peripheral wall of the outer pipe (2), and the separation space (4) partitioned and sealed at the upper end are depressurized from atmospheric pressure. Water collecting pipe. Outer tube (2) the inner tube inside the arrangement of (3), a well for collecting water pipe according to claim 1, characterized in that a substantially coaxially.   The water collecting pipe for a well according to claim 1 or 2, wherein the lower ends of the outer pipe (2) and the inner pipe (3) are sealed.   The water collecting pipe for a well according to claim 1, 2, or 3, wherein the water outlet (32) of the inner pipe (3) is located near the lower end of the inner pipe (3).     5. The water collecting pipe for wells according to claim 1, wherein the pressure reducing means is a pressure reducing pump.

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