JP4895579B2 - Air shielding device in liquid tank - Google Patents

Description

  The present invention relates to an air shielding device in a liquid receiving tank, and more particularly, for example, applied to a recharge method for returning groundwater pumped up to lower groundwater level when excavating on groundwater having a high groundwater level. Further, the present invention relates to an apparatus for preventing dissolved iron and the like from being oxidized by shielding groundwater from the atmosphere in a water receiving tank.

  When excavating the ground to construct an underground structure, if the groundwater level is high, countermeasures such as a groundwater level lowering method or a chemical injection method are implemented. The groundwater level lowering method is a method for stabilizing the ground by pumping water from the ground and lowering the groundwater level at the necessary construction site. This groundwater level lowering construction method is a reliable groundwater countermeasure construction method against the waterstop construction method such as the chemical solution injection construction method, and is therefore excellent in safety especially in the construction under the railway.

  By the way, if the groundwater pumped up by the groundwater level lowering method is discharged into the sewers and rivers as it is, it will cause damage such as subsidence of the surrounding ground and lowering of the water level of the wells. For this reason, a method of returning the pumped groundwater to the ground, that is, a recharge method is widely implemented.

  In this recharge method, since it is difficult to make the pumped amount and the injected water uniform, generally, a method is adopted in which the pumped-up groundwater is once received in a receiving tank and then returned to the ground. In this case, a water receiving tank is used that is open to the atmosphere in order to cope with fluctuations in the pumping amount and the water injection amount. For this reason, when the component which precipitates by oxidation, such as iron, is contained in groundwater, the phenomenon that the pumped-up groundwater will contact the oxygen in air in a receiving tank, and the oxide will precipitate. Oxidized precipitates such as iron contained in groundwater cause clogging of the condensate well walls and filters when returned to the ground, and when clogging progresses, return efficiency deteriorates, and in some cases sewerage There are times when it is forced to drain into rivers and rivers.

For this reason, conventionally, in order to prevent clogging due to oxides such as iron, a measure has been adopted in which water treatment equipment is installed on the ground and water treatment of the returned groundwater is performed (for example, Patent Documents). 1). However, this water treatment method has many problems such as high costs for equipment and the need to treat the product generated by the treatment, and the development of a simpler method has been desired.
JP-A-8-71594

The present invention has been made based on the technical background as described above, and achieves the following object.
An object of the present invention is, for example, to provide an air shielding device for a liquid receiving tank that can prevent oxidation of iron or the like contained in groundwater in a recharge method and eliminate the need for water treatment equipment.

The present invention employs the following means in order to achieve the above object.
That is, the present invention is an apparatus for shielding the liquid in the liquid receiving tank from the atmosphere in the open-type liquid receiving tank,
A floating member installed above the liquid level in the liquid receiving tank, and a shielding member for blocking contact between the liquid level and the atmosphere;
A sealing member that is installed so as to block between the shielding member and the inner wall of the liquid receiving tank, and that allows the shielding member to move up and down with the liquid level fluctuation of the liquid receiving tank;
The shielding member includes a shielding sheet and a large number of spherical floating bodies attached to a lower surface thereof, and the sealing member includes a large number of small spherical floating bodies filled between the shielding member and the inner wall of the liquid receiving tank. It exists in the air shielding apparatus in the liquid receiving tank characterized by comprising.

  More specifically, a frame is attached to the outer peripheral edge of the shielding sheet.

  According to the present invention, for example, when applied to a water receiving tank of the recharge method, the groundwater pumped into the water receiving tank is always covered with the shielding member and the sealing member so that the water surface is shielded from the atmosphere. The oxygen inside does not dissolve. For this reason, an increase in the amount of dissolved oxygen in the groundwater can be suppressed, and iron contained in the groundwater can be prevented from oxidizing and the oxides from being precipitated. Therefore, a water treatment facility for removing oxides is not necessary.

  In addition, since the seal member is composed of a large number of small spherical floating bodies, even if the water level of the water receiving tank fluctuates, the shielding member can move up and down with the fluctuation of the water level, and can respond to fluctuations in the water level while maintaining the shielding property. be able to.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiment shown in FIG. 1 is an example in which the apparatus according to the present invention is applied to a water receiving tank used in a recharge method. In the recharge method, groundwater is pumped from the pumping well 1 through the pumping pipe 3 by the pumping pump 2, and the groundwater level of the construction site such as excavation work is lowered. This is a method of returning from the condensate well 6 through the water pipe 5 into the ground. In such a recharge method, the groundwater pumped up is temporarily received by the open-air receiving tank 10 as described above in order to cope with fluctuations in the pumped amount and the injected water amount.

  2 is a cross-sectional view showing the inside of the water receiving tank 10, and FIG. 3 is a plan view. The atmospheric shielding device according to the present invention includes a shielding member 11 and a seal member 12. In this embodiment, the shielding member 11 includes a shielding sheet 13 and a large number of spherical floating bodies 14. The shielding sheet 13 has a smaller outer dimension than the inner method of the water receiving tank 10 and is made of a waterproof material that is not soluble in water, for example, a synthetic resin. The water-impervious sheet 13 may be either a sheet having a thin sheet thickness and being flexible, or a sheet having a relatively thick sheet thickness and being difficult to bend.

  Many spherical floating bodies 14 are attached to the lower surface of the shielding sheet 13 in close contact with each other. The spherical floating body 14 is also made of a water-insoluble material such as synthetic resin. The attachment method to the shielding sheet 13 can be appropriately selected from fixing with an adhesive, fixing with a fixing tool, and the like. By attaching the spherical floating body 14 to the shielding sheet 13, the shielding sheet 13 floats away from the water surface in the water receiving tank 10. The spherical floating body 14 may float on water and may be solid or hollow.

  A frame 15 is attached to the outer peripheral edge of the shielding sheet 13. This frame 15 is for ensuring the filling space of the sealing member 12 and preventing the groundwater in the water receiving tank 10 from overflowing on the shielding sheet 13 when the groundwater undulates. A rib 16 is provided inside the frame body 15.

  The sealing member 12 is composed of a large number of small spherical floating bodies 17 and is filled in a space between the shielding sheet 13 and the inner wall of the water receiving tank 10 so as to close it. The small spherical floating body 17 has a small diameter or a granular shape so as to be densely packed, and a spherical diameter in the range of φ5 mm to 200 mm is selected. The small spherical floating body 17 is also made of a waterproof material that is not soluble in water, for example, a synthetic resin, and may be solid or hollow.

  According to the shielding device as described above, the groundwater pumped into the water receiving tank 10 is always covered with the shielding member 11 and the sealing member 12 so that the water surface is shielded from the atmosphere. Does not dissolve. For this reason, an increase in the amount of dissolved oxygen in the groundwater can be suppressed, and iron contained in the groundwater can be prevented from oxidizing and the oxides from being precipitated. Therefore, a water treatment facility for removing oxides is not necessary.

  Further, since the sealing member 12 is composed of a large number of small spherical floating bodies, even if the water level of the water receiving tank 10 fluctuates, the shielding member 11 can move up and down with the fluctuation of the water level, and the water level fluctuates while keeping the shielding property. It can be made to correspond. Furthermore, the shielding device according to the present invention can be used a plurality of times.

  The shielding device according to the present invention is effective not only for preventing oxidation of iron and the like in groundwater, but also for preventing evaporation of groundwater in the water receiving tank, keeping the groundwater warm, and preventing bacteria from breeding in the groundwater.

  The above embodiment is merely an example, and the present invention can take various aspects. For example, in the above embodiment, the shielding member is composed of a shielding sheet and a spherical floating body, but the shielding member can be composed of a box-like (solid or hollow) floating in water. Moreover, in the said embodiment, although the shielding apparatus by this invention was applied to the water receiving tank used with a recharge construction method, it is not restricted to this, It is applicable to the general water receiving tank and also the liquid receiving tank generally receiving other liquids, such as oil. .

It is a figure for demonstrating the outline | summary of a recharge construction method. It is sectional drawing of the water receiving tank to which this invention is applied. It is a top view of a water receiving tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pumping well 2 Pumping pump 3 Pumping pipe 4 Injection pump 5 Injection pipe 6 Condensate well 10 Receiving tank 11 Shielding member 12 Sealing member 13 Shielding sheet 14 Spherical floating body 15 Frame 16 Rib 17 Small spherical floating body

Claims (2)

A device for shielding the liquid in the liquid receiving tank from the atmosphere in an open air receiving tank,
A floating member installed above the liquid level in the liquid receiving tank, and a shielding member for blocking contact between the liquid level and the atmosphere;
A sealing member that is installed so as to block between the shielding member and the inner wall of the liquid receiving tank, and that allows the shielding member to move up and down with the liquid level fluctuation of the liquid receiving tank;
The shielding member includes a shielding sheet and a large number of spherical floating bodies attached to a lower surface thereof, and the sealing member includes a large number of small spherical floating bodies filled between the shielding member and the inner wall of the liquid receiving tank. An air shielding device in a liquid receiving tank, comprising:   The atmosphere shielding device in the liquid receiving tank according to claim 1, wherein a frame is attached to an outer peripheral edge of the shielding sheet.

Images