JPS6326029B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an earthquake-resistant water storage tank that can secure drinking water even when water supply and sewerage services are cut off due to unexpected accidents such as earthquakes, traffic accidents, and road cave-ins. A water pipe is connected to a vertical cylindrical water tank with an earthquake-resistant structure, and the water in the tank is constantly circulated and replaced to prevent water from spoiling and to ensure that purified water suitable for drinking can be taken out at any time.

As this type of earthquake-resistant water storage tank, one in which a water inflow pipe and an outflow pipe are connected to a water tank with an earthquake-resistant structure is already in use, but in the case of these conventional earthquake-resistant water storage tanks, It seems that sufficient consideration was not given to the location of the inflow and outflow pipes in the water tank and the direction of water flow, and as a result, the water circulation effect (replacement effect) on the water flow rate was low.
There was a risk of dead water. As a result, the water often rotted in the tank and became unfit for drinking.

By the way, as the water tank itself, a vertical concrete or steel water tank or a horizontal steel water tank is generally used. First of all, concrete water tanks are constructed by assembling multiple concrete segments on-site since it is difficult to pour concrete all at once at the installation site. However, since concrete segments cannot be welded, water may leak from the joints, and cracks often occur, causing water leakage. In addition, in concrete water tanks, there are cases where a support column is installed in the center of the tank to support the upper floor plate, but this support not only significantly obstructs the circulation or exchange of water (but also because almost all of the water in the tank must be replaced). for,
(It is necessary to pass water four to five times the capacity of the water tank.) As will be described later, there also arises the problem that it becomes impossible to arrange the outflow pipe in the center.

On the other hand, steel water tanks are generally constructed from a single plate, but when a single plate is used, the plate must be thicker in order to increase its strength, which poses problems in terms of installation work, cost, etc. Therefore, the present applicant has already proposed a steel water tank with ribs arranged vertically and horizontally on its inner surface (Utility Application No. 53-076156 (Utility Model Application No. 178116)).
This had the disadvantage that the ribs were exposed on the inner surface of the tank, reducing the water circulation effect. In addition, horizontal water tanks have the disadvantage of requiring a large construction space, and in terms of water circulation, it is structurally difficult to eliminate stagnation points.

The present invention is characterized in that the pipe end of the inflow pipe disposed near the upper inner wall surface of a vertical cylindrical steel water tank is attached so as to face tangentially to the diameter line of the water tank, and the pipe end of the inflow pipe is installed near the inner wall surface of the upper part of a vertical cylindrical water tank made of steel. The pipe end of the outflow pipe arranged on the side is opened toward the bottom surface, thereby increasing the circulation effect or exchange effect of water in the water tank, and furthermore, forming the inner wall of the water tank flat, This is an attempt to solve the aforementioned problems that had conventionally been required to be solved.

In addition, paint is generally used as a means of preventing rust on the inner surface of steel water tanks, but since the paint may peel off and cause rust on the inner surface of the water tank, it is not recommended as a means of preventing rust on drinking water tanks. It's inappropriate. Therefore, in the present invention, this problem is also solved by forming a synthetic resin layer on the inner surface of the water tank instead of the paint.

Incidentally, there are two types of earthquake-resistant water storage tanks: a pressure tank type that is directly connected to the water main and receives large internal pressure, and a water receiving tank type that receives only static pressure and has a pump or the like attached to the outflow pipe. Applicable to both.

The present invention will be specifically described below based on illustrated embodiments.

First, let's talk about the piping system. In Figure 1 showing the pressure water tank type directly connected to the water main, the code 1
is a water main, 2 is a vertical cylindrical earthquake-resistant water tank,
3 and 4 are from water main 1 to earthquake-resistant water tank 2, respectively.
These are the inflow pipe and outflow pipe introduced into the tank. 5, 6, 7
are valves provided on the water main pipe 1, inflow pipe 3, and outflow pipe 4, respectively, and 8 and 9 are expansion joints of the inflow pipe 3 and outflow pipe 4, respectively.

One end of the inflow pipe 3 is introduced into the earthquake-resistant water storage tank 2 and bent into an inverted L shape, as shown in FIGS. It is installed so that it faces approximately tangentially, so that tap water flows into the tank above the water storage tank 2 approximately tangentially.

The outflow pipe 4 is as shown in Figures 1, 2, 3, and 6.
It is introduced vertically from above the center of the water storage tank 2 so that its open end 11 is located below the center of the water storage tank 2.

The reference numeral 12 is a water sampling pipe for pumping up water from the water tank 2 when necessary, and the reference numeral 13 is a manual pump. 14
is a water conduit for a fire hydrant that is installed when the water tank 2 is used also as a fire prevention water tank. 15 is an air pipe, and 16 is an air valve attached to the air pipe 15. This air valve 16 is closed when the water storage tank 2 is filled with water, but when the water in the water storage tank 2 is pumped up by the water sampling pipe 12 or the water conduit pipe 14 for fire hydrant, the air valve 16 is opened and the water storage tank 2 is closed. Introduce air inside. Reference numeral 17 denotes an overflow pipe extending from the water storage tank 2 to the side gutter 18, and is provided with a gate valve 19 and a safety valve 20 on the way.

Next, the configuration of the water tank 2 will be explained. This is a vertical cylindrical steel water storage tank with a peripheral wall 2
1, an upper floor plate 22, and a lower floor plate 23. The peripheral wall 21 has ribs 26, 2 between the inner wall 24 and the outer wall 25.
6... is provided in the vertical direction, the horizontal direction, or both directions to form a double hull structure. As an example, the peripheral wall 21 is composed of an upper peripheral wall 27 and a lower peripheral wall 28, each of which includes a plurality of upper segments 29, 29... formed in an arc shape and a plurality of lower segments 30, 30... formed in a ring shape. Connect and configure. The upper floor plate 22 and the lower floor plate 23 have ribs 33, 33...3 on the upper surface of steel substrates 31, 32, respectively.
4, 34... are attached vertically or horizontally or both, and the upper floor plate is welded to the upper segment and the lower floor plate is welded to the lower segment, respectively, and then concrete 35, 36 is poured.

In addition, the steel parts on the inner surface of the water tank 2, that is, the inner surface of the inner wall 24, the lower surface of the upper floor plate 22, and the upper surface of the concrete lower floor plate 36 are made of synthetic resin with excellent adhesion and penetration resistance as a rust preventive measure. layer 3
7 (for example, an epoxy resin layer). Note that the effect can be further enhanced by further adhering a glass fiber layer to the surface of this synthetic resin layer 37.

Next, to describe the construction procedure for burying the water tank 2, first, the installation site of the water tank 2 is excavated relatively shallowly and the ground is leveled, and then a plurality of arc-shaped lower segments 30, 30... are welded into a ring shape to form the lower peripheral wall 28. Subsequently, the upper peripheral wall 27 formed by welding the upper segments 29, 29, . . . into a ring shape is welded to the upper end surface of the lower peripheral wall 28 to form the peripheral wall 21 of the water tank. Next, the surrounding wall 2
The soil inside 1 is excavated to sink the surrounding wall 21 into the well.

Next, the construction of the lower floor board 23 is carried out. First, a pit 39 is excavated at a position corresponding to the pot hole 38 formed in advance on the steel base plate 32 of the lower floor board 23, and a chestnut stone is placed around the pit 39. 40 (see figures 9 and 10). After pouring concrete 41 onto the chestnut stone 40 while draining spring water from the pit 39, the steel substrate 32 of the lower floor plate 23 is attached and welded to the lower end of the inner wall 24 of the lower peripheral wall 28, and the steel substrate 32 Concrete 36 is poured on top. In addition, numeral 45 is a chestnut stone stopper, and 46 is a pot hole closing plate.

After that, the steel substrate 31 on the upper floor plate 22
is welded to the upper end surface of the upper peripheral wall 27, and after piping work is performed, concrete 35 is placed on the steel substrate 31. 44 is a manhole provided in the upper floor board 22. Note that a reinforcing member (not shown) is provided between the upper inner surface of the upper peripheral wall 27 and the lower peripheral edge of the steel substrate 31.
may be provided.

Next, the effects of the present invention will be explained. First, talking about the flow of water, water introduced into the earthquake-resistant water tank 2 from the water main 1 via the inflow pipe 3 flows into the water storage tank 2 from the pipe end 10 of the inflow pipe located near the upper inner wall surface. Since the water flows in substantially tangential direction, the water in the water tank 2 generates a uniform swirling flow. On the other hand, since the water in the water tank 2 is discharged out of the tank from the pipe end 11 of the outflow pipe located below the center, the water in the water tank 2 also causes vertical movement. That is,
Water introduced into the water storage tank 2 from the water main 1 flows along the wall inside the water storage tank 2 and moves to the upper, middle, and lower areas, and is sequentially returned to the water main 1 through the pipe end 11 of the outflow pipe. Return. Therefore, the water circulation effect and water exchange effect (see the experimental results described later), which can be understood in relation to the water flow rate, will be significantly improved.
There is no risk of water spoiling in the water tank 2,
Purified water suitable for drinking can be obtained even during water supply outages due to earthquakes, etc.

On the other hand, regarding the water tank itself, the present invention uses a steel double-hull structure for the peripheral wall, so even if the plate thickness is reduced, it still maintains the internal pressure resistance (5 kg/cm ² to 50 tons) required for a pressure water tank directly connected to the water mains. /cm ² ) and exhibits excellent earthquake resistance that can meet the external earth pressure (8.2t/m ² ) required for earthquake-resistant design. Since there is no exposure to water, it does not impede the water circulation effect.
It is also ideal for attaching synthetic resin as a rust preventive means to the inner surface of the peripheral wall of the water tank. In addition, since the water storage tank of the present invention is made of steel, it goes without saying that there is no need for supports on the upper floor plate that significantly impede circulation or exchange of water.

In addition, since the water storage tank according to the present invention has a vertical cylindrical shape, a construction method in which the tank surrounding wall is assembled and formed at the installation site, the soil inside the tank surrounding wall is excavated, and the tank body slides and sinks under its own weight ( Izutsu subsidence method)
It can be constructed with. Therefore, because it cuts earth retaining roots, it can be installed in narrow sites where steel sheet piles cannot be driven, and this eliminates the problems of noise and vibration caused by driving and pulling out sheet piles, and prolonging the construction period.
It becomes possible to solve all problems such as the increase in construction area.

<Experimental Results> In order to investigate the difference in the water circulation effect or exchange effect due to the difference in the installation position of the inflow pipe and the outflow pipe in the water storage tank, especially the installation position and direction of each pipe end, the present inventors The experiment was conducted using a 100l model aquarium.

In conducting this experiment, we conducted a preliminary experiment using food coloring as a labeling substance, and then adopted the following labeling compound, which has a lower specific gravity than the food coloring.
We confirmed the diffusion effect during water injection and the discoloration effect during drainage.

The model aquarium used is as follows (11th
(see figure). In this figure, parts or parts corresponding to those shown in FIGS. 1 to 10 are indicated by adding a dash (') to the above-mentioned reference numerals.

Model aquarium A...corresponds to an embodiment of the present invention.

Model aquarium B: Same as model aquarium A, except that the end 10' of the inflow pipe faces straight down, allowing water to flow in vertically.

Model tank C: Same as model tank A, except that the height of the inlet pipe end 10' has been lowered to approximately the center of the tank.

Model aquarium D: Same as model aquarium A, except that the inlet pipe end 10' is lowered to the lower part of the tank, and the outlet pipe end 11' is raised to the upper part of the tank.

Incidentally, the inflow pipe 3' in each of the above model water tanks was connected to an upper inflow water adjustment tank, and the outflow pipe 4' was connected to a metering pump.

In the experiment, N-(1-naphthyl)ethylenediamine hydrochloride as a labeled compound was placed in each model tank in advance.
After filling with 5ppm aqueous solution, add fresh water from inlet pipe 3'.
This was carried out by inflowing at a rate of 5/min, collecting samples flowing out from the outflow tube 4' at appropriate time intervals, and measuring their concentrations.

According to experiments, it was confirmed that even if the flow rate and flow rate were varied, there was almost no change in the concentration of the labeled compound unless the piping position (including direction) was changed. Therefore, the present inventors fixed the flow rate (flow rate per unit time) and investigated the concentration change depending on the piping position, thereby confirming the effects of the present invention. The results of the above experiment are shown in FIG. 12 as changes over time in the concentration of the effluent. The concentrations shown in the figure were calculated based on a 5 ppm aqueous solution of the above compound as 100%.

As shown in Figure 12, the concentration of the effluent after 40 minutes had passed after the start of water flow (200 liters, that is, twice the tank capacity) was the lowest in model tanks A and B; Each was approximately 1.0%. That is,
In the case of model aquariums A and B, approximately 99.0% of the water was replaced by passing water twice the tank capacity. Furthermore, regarding the effluent concentration after the above point, the best reduction effect was seen in the case of model aquarium A; for example, when three times the tank capacity of water was passed through, the effluent concentration was approximately 0.1%, which was approximately 99.9%. This means that % of the water has been replaced. Thereafter, with the passage of time, the concentration of the effluent in model aquarium A decreased significantly compared to the other model aquariums.
Therefore, it has been found that the model aquarium A corresponding to the embodiment of the present invention is superior to other model aquariums in terms of water circulation and replacement effects.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG.
A cross-sectional view along the line III-III in Figure 4, and Figure 4 is a cross-sectional view along the line IV-III in Figure 1.
5 is a sectional view taken along line V-V in Figure 1, Figure 6 is a sectional view taken along line VI-VI in Figure 2, and Figure 7 is a sectional view taken along line VII-VII in Figure 6. , FIG. 8 is a plan view showing the upper floor board, FIG. 9 is a plan view showing the lower floor board, FIG. 10 is a sectional view taken along line X-X in FIG. 9, and FIG. 11 is a sectional view showing each model water tank. FIG. 12 is a graph showing the change in effluent concentration over time as an experimental result. 1: Water main, 2: Earthquake-resistant water tank, 3: Inflow pipe, 4: Outflow pipe, 5 to 7: Valve, 8, 9: Expansion joint, 10: Pipe end of inflow pipe, 11: Outflow pipe end,
12: Water sampling pipe, 13: Manual pump, 14: Fire hydrant water pipe, 15: Air pipe, 16: Air valve, 17:
Overflow pipe, 18: Side gutter, 19: Gate valve, 20: Safety valve, 21: Peripheral wall, 22: Upper floor board, 23: Lower floor board,
24: Inner wall, 25: Outer wall, 26: Rib, 27: Upper peripheral wall, 28: Lower peripheral wall, 29: Upper segment, 30: Lower segment, 31, 32: Steel substrate, 33, 34: Rib, 35, 36: Concrete, 37: Synthetic resin, 38: Pot area, 39: Pit, 40: Chestnut stone, 41: Concrete, 44: Manhole, 45: Chestnut stone stop, 46: Pot area closing plate.

Claims (1)

[Scope of Claims] 1. The circumferential wall of a vertical cylindrical earthquake-resistant steel water tank has a double-hull structure with ribs provided between the inner wall and the outer wall, and one end of an inflow pipe and an outflow pipe provided in the water tank is Each is connected to a water main, and the other end is opened into a water storage tank, and the open end of the inflow pipe is connected to the inner wall surface near the upper inner wall surface of the water storage tank.
An earthquake-resistant water storage tank characterized in that the outflow pipe is oriented substantially tangentially, and the open end of the outflow pipe is located below the center of the tank.