JP2013170357A - Pumping/pouring system for ground water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pumping/pouring system of simple constitution capable of preventing oxygen from being mixed with ground water substantially completely at low cost.SOLUTION: A pumping/pouring system for ground water that includes well casings 11, 12 which extend up to water-bearing layers W1, W2 and taking ground water in from intake parts 17, 18, and water pipes 13, 14 for pumping or pouring which are inserted into the well casings 11, 12 and extend into ground water in the well casings 11, 12 has width-reduction area formation members 15 which are inserted into gaps between outer surfaces of the water pipes 13, 14 and inner surfaces of the well casings 11, 12 and make intervals of the gaps small to form width-reduction areas. The width-reduction area formation members 15 determine such widths that levels of the ground water are always positioned above lower ends of the width-reduction areas and convection carrying oxygen into the ground water in the width-reduction areas is not generated.

Description

  The present invention relates to a pumping system for pumping groundwater from an aquifer and using it for air conditioning or the like, or a water injection system for pouring groundwater into an aquifer.

  Since soil contains a lot of iron and manganese, groundwater contains metals such as iron and manganese, but oxygen is consumed by decomposition of organic matter in the soil, and groundwater contains almost no oxygen. Because there is no such metal, these metals exist in the groundwater in an ionic state. Therefore, when groundwater containing these metal ions is pumped from the aquifer, or when pumped groundwater is poured into the aquifer, the groundwater comes into contact with the atmosphere, oxygen is taken into the groundwater, and the metal ions are oxidized. To do.

For example, iron ions (Fe ²⁺ ) are oxidized to ferric hydroxide (Fe (OH) ₃ ), and a part of the ferric hydroxide becomes particulate or colloidal iron hydroxide. Suspend in groundwater and attach red rust to the screens of pumps and heat exchangers. Since this red rust causes the capacity of the pump and heat exchanger to deteriorate or break down, the screen of the pump and heat exchanger must be periodically cleaned or replaced to remove the red rust. There is a problem.

In addition, iron hydroxide accumulates at the bottom of the well casing and in the aquifer, raising the water level during water injection, which makes it impossible to inject groundwater.
Furthermore, there is a problem that aerobic bacteria propagate due to oxygen being taken into the groundwater, and cause odors inside the water pipe and well casing.
In this way, although heat exchange systems using groundwater are excellent in terms of energy saving and improving the heat exchange rate, groundwater containing a large amount of metal ions tends to be avoided, hindering the spread of heat exchange systems using groundwater. It is one of the reasons.

In order to solve such problems, some attempts have been made to prevent contact between the groundwater and the atmosphere during pumping or water injection.
For example, in Patent Document 1 (Japanese Patent Publication No. 8-25537), an air chamber sealed above the groundwater level in the well casing is made and air mixed in the groundwater is separated so that air is not mixed into the groundwater. A method of providing an air separation device is proposed.

Moreover, in patent document 2 (Unexamined-Japanese-Patent No. 2009-122102), the density | concentration for measuring the oxygen concentration in a water pipe while sealing the upper part of a water pipe (well casing) and filling the inside of the water pipe with an inert gas. A method of providing a total has been proposed.
Furthermore, in addition to the above-mentioned documents, attempts have been made to seal the well casing using water expansion rubber or the like.

Japanese Patent Publication No. 8-26537 JP 2009-121062 A

However, all of the techniques described in the above documents attempt to shut off the atmosphere by sealing the well casing, but it is extremely difficult to keep the inside of the well casing where the water level fluctuates constantly in a completely sealed state. There is a problem.
Further, the method of injecting an inert gas into the well casing or separating the mixed air has a problem that a large-scale device is required and the cost is increased.
Furthermore, since the method described in the above document requires the installation of a new device or a device for measuring the concentration of dissolved oxygen, it is difficult to apply it to an existing pumping / pouring system as it is. There is a problem that must be built.

  The present invention has been made in view of the above problems, and an object thereof is to provide a pumping / water injection system that can be implemented at a low cost with a simple configuration and can almost completely prevent oxygen from being mixed into groundwater.

In solving the above problems, the inventors of the present invention investigated the relationship between the depth of groundwater and the amount of dissolved oxygen in several well casings in Fukui City. The results are shown in the graphs of FIGS. 3 and 4, the vertical axis represents the water depth (m), and the horizontal axis represents the dissolved oxygen content (ppm). Note that FIG. 3 is a survey conducted in July 2011, and FIG. 4 is a survey conducted in September 2011 for the same place as FIG.
From the graph of FIG. 3, it can be seen that the amount of dissolved oxygen is large near the groundwater surface and decreases as the water depth increases, and becomes almost zero when the water depth exceeds 1.5 m. However, in the data for September, as shown in FIG. 4, the dissolved oxygen amount was large up to a certain depth, and when the depth exceeded the certain depth, the amount of dissolved oxygen decreased rapidly.

  When the inventor of the present invention examined the transition from the graph of FIG. 3 to the graph of FIG. 4, it was assumed that dissolved oxygen was transported from the surface of the groundwater to a certain depth by convection of the groundwater in the well casing. In particular, when the warm drainage during cooling is poured into the aquifer, it can be assumed that the temperature stratification of the groundwater in the well casing collapses and convection occurs, and a large amount of oxygen is taken into the groundwater from the water surface. Therefore, if groundwater convection that transports oxygen from the surface of groundwater that is in contact with air to the depth of groundwater is suppressed, precipitation and bacteria due to oxidation of metal ions in groundwater can be avoided without completely sealing the well casing. I thought that it was possible to prevent breeding.

  That is, the pumping / pouring system according to claim 1 is a well casing having a water intake portion extending to an aquifer, and a pump for pumping or pouring water that is inserted into the well casing and extends to the ground water in the well casing. In a groundwater pumping / pouring system having a water pipe, a reduced width region is formed which is inserted into a gap between an outer surface of the water pipe and an inner surface of the well casing and forms a reduced width region by reducing the gap interval. The reduced-width region forming member has a groundwater level always above the lower end of the reduced-width region, and does not cause convection of groundwater that transports oxygen within the reduced-width region. Further, the width of the gap is determined.

If the pumping / water injection system of the present invention is used for heat exchange such as cooling and heating, the reduced width region forming member may be formed of a heat insulating material and wound around the outer surface of the water pipe as described in claim 2. .
In the pumping / pouring system of the present invention, as described in claim 3, the pumped ground water may be poured into the same or different aquifer. By doing so, ground subsidence due to excessive pumping of groundwater can be prevented.

According to the present invention, it is possible to almost completely prevent oxygen from being mixed into the groundwater to suppress the occurrence of red rust, and without causing the water level at the time of water injection to rise in the aquifer on the water injection side, It is possible to prevent a decrease in the capacity or failure of the exchange and to suppress the generation of bacteria, thereby reducing the burden on the operator by eliminating frequent periodic inspections and cleaning.
As described above, according to the present invention, a pumping / water injection system capable of promoting effective use of an existing aquifer containing a large amount of iron and improving energy saving and heat exchange rate is provided at low cost. It becomes possible to do.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram for explaining an overall configuration of an apparatus according to an embodiment in which the pumping / pouring system of the present invention is applied to a cooling / heating apparatus using groundwater, and FIG. 2 is a part of the pumping / pouring system of FIG. It is an enlarged view of the fracture | ruptured main part.

  The pumping / water injection system 1 is driven from the ground surface G into the ground, and the first well casing 11 reaching the first aquifer W <b> 1 and the first water intake portion 17 at the bottom of the well casing 11. And a pumping pipe 13 for pumping whose tip extends to the groundwater of the aquifer W1. The water supply pipe 13 exits from the upper end of the well casing 11 to the ground surface G and is connected to a heat exchanger H for cooling and heating.

  The second well casing 12 is driven from the ground surface G into the second aquifer W2 different from the first aquifer W1. And the water supply pipe 14 extended to the ground water of the 2nd aquifer W2 taken in from the intake part 18 is provided in the bottom part of this well casing 12. FIG. The water pipe 13 and the water pipe 14 are connected to a heat exchanger H, and groundwater pumped from the first aquifer W1 by the pump P is sent to the heat exchanger H through the water pipe 13, and the heat exchanger H The groundwater that has been subjected to the heat exchange is poured into the second aquifer W <b> 2 through the water pipe 14.

  The water pipe 13 and the water pipe 14 are preferably resin pipes from which iron ions do not elute, and are formed of a material having a lower oxygen permeability (for example, vinyl chloride) than a material having a higher oxygen permeability (for example, polyethylene). preferable. In the case of using a metal pipe, it is possible to use a metal pipe with little corrosion, for example, a polyethylene three-layer pipe with aluminum insertion, in consideration of the quality of groundwater.

  In this pumping / water injection system 1, the flow of the aquifers W1 and W2 is loose. For example, groundwater pumped from the first aquifer W1 by the pump P is supplied to the heat exchanger H through the water supply pipe 13, After being used for cooling in summer, the groundwater whose temperature has risen is returned to the second aquifer W2 through the water pipe 14. And by switching the flow of groundwater in winter and reversing the pumping side and the water injection side, the groundwater with high temperature returned to the second aquifer W2 can be used for heating.

  A fitting body 15 as a reduced width region forming member is fitted on the outer surface of the water pipe 13. The fitting body 15 is interposed in a gap between the outer surface of the water pipe 13 and the inner surface of the first well casing 11 to form a reduced width region 19. By forming the fitting body 15 with a heat insulating material, the temperature change of the pumped ground water can be suppressed and the efficiency of air conditioning and the like can be increased. As the fitting body 15, a commercially available pipe cover that is generally used for heat insulation such as a water pipe can be used.

In this embodiment, the water injection side is configured in the same manner as the water pumping side. That is, the fitting body 15 is fitted on the outer surface of the water pipe 14, and a reduced width region 19 is formed between the outer surface of the water pipe 14 and the inner surface of the second well casing 12.
As shown in FIG. 2, the length of the fitting body 15 may be such that at least the water level during pumping is always above the lower end of the fitting body 15.

  In addition, the width S of the reduced width region 19 formed by the fitting body 15 is such that convection of groundwater that conveys oxygen from the surface of the groundwater to the deep portion within the reduced width region 19 even if the groundwater level fluctuates. Select the one that does not occur. If the width S is too small, it will be difficult to insert the fitting 15 into the well casings 11 and 12, and if the width S is too large, oxygen will be carried into the groundwater by convection of the groundwater. The width S varies somewhat depending on various conditions such as the diameter and length of the well casing and the water pipe, the groundwater temperature, the type of the fitting 15 and the like, but is preferably selected within the range of 1 mm to 12 mm. It is more preferable to select within the range of 10 mm.

  The width S can be determined, for example, by providing a DO sensor 20 in the groundwater as shown in FIG. 2 and measuring the concentration of dissolved oxygen in the groundwater. For example, if the dissolved oxygen concentration distribution at each depth is as shown in FIG. 3 even when pumping and water injection are repeated, the width S is changed from the largest to the smaller one, and the surface of the groundwater Assuming that there is no convection in the groundwater that carries oxygen from the depth to the depth, the dimension at that time is determined as “width S”.

[Example]
Examples of the present invention will be described below.
[Example]
(1) Well casing inner diameter 77mm
(2) Fitting body Polyethylene pipe containing urethane foam
Outer diameter 67mm Inner diameter 32mm
(3) Water pipe Made of hard vinyl chloride
Oxygen permeability constant 240cc · 20μm ³ · 24hrs · atm
Inner diameter 25mm, outer diameter 32mm
(4) Clearance dimension S 5mm
(5) Iron content in groundwater 52ppm
[Comparative example]
As a comparative example, an experiment was conducted with a conventional pumping / water injection system without a fitting.

[Conclusion]
The groundwater was pumped from the first well casing 11 at a rate of 20 liters per minute for 8 hours every day and poured into the second well casing 12 of another aquifer.
As a result, in the embodiment, no increase was observed in the water level during the water injection of the second well casing 12 even though the operation was continued for two and a half months, and no clogging was observed in the screens of the heat exchanger and the pump. It was.
On the other hand, in the comparative example, the water level at the time of water injection of the second well casing 12 rose in two and a half months, and it became difficult to inject all of the pumped ground water into the second well casing 12. Also, iron oxide adhered to the screens of heat exchangers and pumps.
From the above, it can be seen that in the present invention, oxidation of iron ions (Fe ²⁺ ) in groundwater is effectively suppressed.

The present invention is not limited to the above description.
For example, in the above description, the water supply side water supply pipe 14 is provided. However, for example, when the pumping / water injection system 1 of the present invention is applied to a snow melting device, the water supply side water supply pipe 14 is not necessarily required. is not.
In addition, the fitting body 15 may be provided so that the water level of the groundwater is always above the lower end of the fitting body 15, but as shown in FIG. You may provide so that the water level of groundwater may always be located in the reduced width area formed by the fitting body 15.

  INDUSTRIAL APPLICABILITY The present invention can be widely applied to a pumping system that pumps and uses groundwater or a water injection system that pours groundwater into an aquifer, and can also be applied to cleaning devices such as cooling or heating devices, snow melting devices, and toilets It is.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic explaining the whole structure of the apparatus concerning embodiment which applied the pumping / water injection system of this invention to the air conditioning apparatus using groundwater. It is an enlarged view of the principal part which fractured | ruptured a part in the pumping / water injection system of FIG. It depends on the result of investigating the relationship between the depth of groundwater in the well casing and the amount of dissolved oxygen in several places in Fukui City. It depends on the result of investigating the relationship between the depth of groundwater in the well casing and the amount of dissolved oxygen in several places in Fukui City.

DESCRIPTION OF SYMBOLS 1 Pumping / injection system 11 1st well casing 12 2nd well casing 13 Water supply pipe 14 Water supply pipe 15 Fitting body 19 Shrinkage width area H Heat exchanger P Pump

Claims (3)

In a groundwater pumping / injecting system having a well casing extending to an aquifer and taking groundwater from a water intake, and a pumping pipe for inserting or pumping water inserted into the well casing and extending to the groundwater in the well casing,
Inserted in a gap between the outer surface of the water pipe and the inner surface of the well casing, and has a reduced width region forming member that forms a reduced width region by reducing the gap interval;
The reduced width region forming member has a width of the gap so that a groundwater level is always located above a lower end of the reduced width region and convection is not generated so as to transport oxygen in the reduced width region. To determine the
A pumping / pouring system characterized by The pumping / water injection system according to claim 1, wherein the reduced width region forming member is formed of a heat insulating material and is wound around an outer surface of the water pipe. The pumping / injecting system according to claim 1 or 2, wherein groundwater pumped from the aquifer is poured into the same or different aquifer as the aquifer.

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