JPH11198991A - Corrosion-resistant apparatus for stainless steel storing tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent side wall upper parts and a ceiling wall corresponding to gas phase part of a storing tank from being corroded by free chlorine drifting in the gas phase part. SOLUTION: Mist is prepd. by using drinking water stored in a storing tank 1 or water introduced form another water source by means of a mist generator 2 and this mist is almost continuously released into a gas phase part in the inner upper part of the storing tank 1 and the mist which is changed to hydrochloric acid by absorbing free chlorine liberated from the drinking water and heavier than air retained in the lower part of the gas phase part is freely drifted in the gas phase part and by utilizing the fact that the water level in the storing tank 1 is changed up and down for a plurality of times a day and the vol. of the gas phase part is accordingly increased and decreased, the mist of hydrochloric acid is discharged to the outside of the storing tank 1 when the vol. of the gas phase part is decreased and the discharged mist is almost continuously condensed on waterdrops on the surface of stainless steel of the gas phase part to turn them into larger waterdrops, which are made to flash down into the liq. phase part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing corrosion of a stainless steel storage tank for storing drinking water.

[0002]

2. Description of the Related Art In general, storage tanks 1 for storing drinking water are installed in public facilities such as schools and hospitals, apartments and condominiums and other apartment buildings, commercial facilities such as office buildings, and factories. . This storage tank 1
As shown in FIG. 9, is a water receiving tank 1A installed on the ground or the basement of a building, or an elevated water tank 1B installed on the roof of a building or an overpass, and the water level of the elevated water tank 1B is When the water level drops, the water pump 11 operates, and the drinking water stored in the water receiving tank 1A via the introduction pipe 12 is pumped to the high water tank 1B via the water pipe 13 and stored in the high water tank 1B. Drinking water is supplied to a destination via a water supply pipe 14.

First, the water receiving tank 1A and the elevated water tank 1B will be described with reference to FIG. An inlet pipe 12 provided with a constant water level valve 121 is introduced into the water receiving tank 1A through its ceiling wall.
A is opened and closed in conjunction with the operation of a ball tap 121a provided in A. A drain pipe 16 provided with a manhole 18, a ventilation pipe 19, an overflow pipe 15, and a drain valve 161 is connected to the water receiving tank 1A.
In addition, the drinking water stored in the water receiving tank 1A is supplied to the pump 11
The pumping pipe 13 for pumping water to the elevated water tank 1B is connected to a lower part of the side wall of the water receiving tank 1A, and its base end opening is an outlet for drinking water stored in the water receiving tank 1A. A valve 131 such as a butterfly valve, a globe valve, or a gate valve is provided in the pumping pipe 13 near the outside of the water receiving tank 1A, and the valve 131 is normally open.

In such a water receiving tank 1A, the water receiving tank 1A
When the drinking water stored in A is taken out by the pump 11 and pumped up to the high water tank 1B and its water level is lowered, the float 121b of the ball tap 121a is lowered following the water level drop, and is linked with the ball tap 121a. The constant water level valve 121 is opened. In this way, the tap water is supplied to the water receiving tank 1A via the introduction pipe 12 and the constant water level valve 121.
Will be introduced. On the other hand, if the water level rises sequentially by introducing tap water, the float 1 of the ball tap 121a
21b rises following the rise of the water level. When the float 121b of the ball tap 121a reaches the upper limit water level HWL, the constant water level valve 121 is closed, and thereafter, the introduction of tap water is shut off.

In order to detect when the water level in the water receiving tank 1A becomes abnormal, a sensor 171 composed of three electrode rods is usually hung from the ceiling wall. That is, when the water level in the water receiving tank 1A is too high and reaches H1, or when the water level is too low and reaches H2, the sensor 171 detects the abnormality and the control panel 17 turns on the alarm lamp 172, An alarm buzzer 173 is sounded to notify the abnormality. In particular, when the water level is too low, the water pump 11 may be in an idling state. Therefore, when the water level reaches H2, the operation of the water pump 11 is stopped.

On the other hand, the elevated water tank 1B is provided with the water receiving tank 1 described above.
A has substantially the same structure as that of the water receiving tank 1A, and the same members as those of the water receiving tank 1A are denoted by the same reference numerals.
Only parts different from A will be described.

[0007] Usually, a sensor 171 composed of five electrode rods is hung from the ceiling wall to detect and control the level of drinking water stored in the elevated water tank 1B. That is, the water level in the elevated water tank 1B is detected by the sensor 171 and controlled by the control panel 17, whereby the pump 1
1 is operated or stopped, and the water level in the elevated water tank 1B is adjusted to an appropriate upper limit water level HWL and a lower limit water level LW.
It is kept between L. In addition, the water level of the elevated water tank 1B becomes too high and reaches H1, and
When the number reaches 2, the alarm is detected, the alarm lamp 172 is turned on, and the alarm buzzer 173 is sounded to notify the abnormality.

[0008] The water level of the drinking water stored in the elevated water tank 1B fluctuates within a set range. That is, when the level of the drinking water stored in the elevated water tank 1B decreases to the lower limit water level LWL due to consumption of the drinking water, the sensor 171 detects the water level and operates the pumping pump 11 to operate the water receiving tank 1A. The drinking water stored in the tank is pumped to the elevated water tank 1B via the pumping pipe 13. On the other hand, when the drinking water is pumped, the level of the drinking water stored in the elevated water tank 1B rises, and when the drinking water reaches the upper limit water level HWL, the sensor 171 detects the water level and stops the operation of the water pump 11. . As described above, the water level in the high water tank 1B always fluctuates between the upper limit water level HWL and the lower limit water level LWL. In addition, a valve 141 such as a butterfly valve, a globe valve, or a gate valve is provided in the water supply pipe 14 connected to the lower part of the elevated water tank 1B, and the valve 141 is normally open.
Then, the drinking water stored in the elevated water tank 1B placed at a high place is supplied to a low place through the water supply pipe 14 using a height difference.

Although not shown in detail, the storage tank 1 such as the water receiving tank 1A or the elevated water tank 1B is generally provided with a joining edge vertically rising from the substrate to the same side on the periphery of the rectangular substrate. The side walls, the bottom wall, and the ceiling wall are formed by sequentially connecting the unit plates provided and formed in a box shape, and the side wall, the bottom wall, and the ceiling wall are assembled and formed. Further, as a material of the unit plate, a metal such as iron, stainless steel or aluminum, or a synthetic resin such as FRP is employed. Among these, from the viewpoints of fire resistance, seismic strength and the like, in recent years, stainless steel, particularly ferritic stainless steel called SUS444, which is resistant to crevice corrosion (electric corrosion), has been used.

By the way, when drinking water is stored in the storage tank 1, a chlorine concentration of 0.1 p.
pm or less is required, and it is necessary to appropriately add sodium hypochlorite into the storage tank 1. For this reason, sterilizing chlorine contained in tap water and the injected sodium hypochlorite is liberated, and the free chlorine is separated into an internal space (gas phase portion) above the surface of the drinking water stored in the storage tank 1. ).

On the other hand, on the inner wall surface corresponding to the gaseous phase portion of the storage tank 1, water droplets are formed due to dew condensation due to the temperature difference between the inside and outside, and when the water level of the storage tank 1 is lowered, the inner wall surface of the draft Water drops adhere to the surface.

The above-mentioned free chlorine continuously dissolves into the water droplets attached to the inner wall surface corresponding to the gas phase portion of the storage tank 1, so that the water droplets become hydrochloric acid, and the hydrochloric acid concentration of the water droplets gradually increases. It gets darker.

In the case of the storage tank 1 made of a synthetic resin such as FRP, there is no effect even if the hydrochloric acid concentration of the water droplets becomes high, but in the case of the storage tank 1 made of stainless steel, the ferrite stainless steel SUS444 Even when the method is adopted, the side wall and the ceiling wall corresponding to the gas phase part are corroded. That is, the depression h due to corrosion is formed on the inner surface of the side wall or the ceiling wall corresponding to the gas phase of the stainless steel storage tank 1 (see FIG. 10).
Is formed.

[0014] Once the depression h due to such corrosion is formed, water droplets always adhere to the depression h, and the corrosion proceeds in a wedge-like manner toward the outer surface. A pinhole p (see FIG. 10) penetrating the side wall or the ceiling wall corresponding to the gas phase is formed.

Although a little water pressure is applied to the side wall of the draft portion between the upper limit water level HWL and the lower limit water level LWL of the storage tank 1, not too much water pressure is applied. Since no water pressure acts on the ceiling wall and the ceiling wall, a stainless steel unit plate having a smaller thickness than the side wall having the lower limit water level LWL or less tends to be used for the side wall above the draft portion and the ceiling wall. For this reason, the pinhole p is easily generated in the side wall and the ceiling wall located above the lower limit water level LWL.

In particular, in the storage tank 1 for storing drinking water, the upper limit water level HWL and the lower limit water level LW are higher than the ceiling wall.
There is a phenomenon that a pinhole p is likely to be generated on the side wall in contact with the draft portion between L and the gas phase portion near the draft portion. It is considered that the cause is that the specific gravity of chlorine gas is larger than the specific gravity of air.

The specific gravity of chlorine gas is 2.4 with respect to 1 air.
5 ("Chemical Handbook" applied, edited by The Chemical Society of Japan, Maruzen Co., Ltd., 2nd revised edition, issued November 10, 1973, 21
Page, Table 1.21 "Properties of chlorine and derivatives").

That is, since chlorine gas is heavier than air, it stays in the lower part of the gas phase. Therefore, the chlorine gas released from the tap water and / or sodium hypochlorite contacts the water surface in the storage tank 1 and stays in a layer on the water surface, and repeats rising and falling as the water level in the storage tank 1 rises and falls. Will be.

That is, the chlorine gas staying in the lower part of the gas phase in the storage tank 1 is discharged from the ventilation pipe 19 attached to the ceiling wall located above the storage tank 1. It is difficult. That is, in column 4 lines 13 to 15 of Japanese Utility Model Publication No. 57-58147, "Most of the chlorine gas decomposed and generated from hypochlorous acid for sterilizing the clean water in the water tank body 1 from the chlorine gas discharge port 7". Is released, "but it is hard to expect that chlorine gas is actually released from the ventilation pipe (chlorine gas discharge port 7).

In addition, chlorine gas released from tap water and / or sodium hypochlorite is continuously diffused into the gas phase and stays in the lower part of the gas phase. The concentration of chlorine gas remaining in the lower part of the phase gradually increases with time.

Therefore, the upper limit water level HWL and the lower limit water level L
It is considered that a large amount of free chlorine is dissolved by water droplets adhering to a draft portion between the WL and a side wall in contact with a gas phase portion in the vicinity thereof, resulting in high-concentration hydrochloric acid, thereby easily generating many pinholes p.

In this way, when the pinhole p is formed in the draft portion, when the water level in the storage tank 1 rises above the pinhole p, the drinking water leaks outward from the pinhole p and the pinhole p It will flow down along the sidewall outer surface below p. Then, after a long period of time, dust, moss and the like adhere to the outer surface of the storage tank 1 in the form of vertical stripes, resulting in a bad appearance. Further, fine insects, bacteria, moss, and the like may enter through the humid pinhole p penetrating from the outer surface to the inner surface of the side wall corresponding to the gas phase portion of the storage tank 1, It is not preferable for hygiene. Further, even if a band-shaped patch plate is brought into contact with a draft portion where pinholes p frequently occur and repair is performed, the pinholes p will be generated again as described above, and the repair must be repeated. .

In recent years, such a phenomenon tends to increase in proportion to an increase in the amount of chlorine used for sterilization due to deterioration of water quality in waterworks.

For this reason, under severe conditions such as a large city where a large amount of residual chlorine is present, the side wall and the ceiling wall corresponding to the gas phase portion of the storage tank 1 are replaced with “super stainless steel” instead of the above-described SUS444 stainless steel. An austenitic ferrite duplex stainless steel called SUS329J4L, which is said to have excellent corrosion resistance to hydrochloric acid, is used.

In addition, a pipe is provided above the overflow port in the tank for storing drinking water, and a sprinkling hole (jet port) is provided in the pipe.
At least a part of the sprinkling hole is directed upward from the horizontal direction, one end of the pipe is guided to the outside of the tank and connected to the pressure water pipe, and a pump or a valve is attached to the pressure water pipe to wash off water droplets attached to the ceiling wall and the side wall. Such storage tanks have also been proposed (see, for example, Japanese Utility Model Laid-Open No. 52-74672 and Japanese Utility Model Laid-Open No. 57-58147).

[0026]

A ferritic stainless steel called SUS444 excellent in crevice corrosion (electric corrosion) is used for a side wall and a bottom wall corresponding to a liquid phase portion of the storage tank 1, and is used for a gas phase portion. In the case of a conventional example in which an austenitic / ferritic duplex stainless steel called SUS329J4L having excellent corrosion resistance to hydrochloric acid so as to be called “super stainless steel” is used for the corresponding side wall and ceiling wall, the manufacturing cost of the storage tank 1 is increased. There is a problem that raises significantly.

Incidentally, SUS329J4L stainless steel is very expensive, about 2.7 times the SUS304 stainless steel, about twice the SUS316 stainless steel, and about 1.5 times the SUS444 stainless steel per unit weight.

In addition, when two types of stainless steel are properly used as described above, inventory management becomes complicated, and a storage space for inventory items must be secured. Moreover,
If the stainless steel used for the gas phase part and the stainless steel used for the liquid phase part are different in shape, they will not be confused, but if the shapes are the same or similar, inventory Not only is it easy to make mistakes, but there is also a risk that the stainless steel used for the gas phase part and the stainless steel used for the liquid phase part may be mistakenly assembled up and down. If the SUS used for the liquid phase is in the gas phase of the storage tank 1 assembled
If 444 stainless steel is used by mistake, as described above, free chlorine dissolves in the attached water droplets to form hydrochloric acid, which corrodes SUS444 stainless steel.

Further, in the normal case where two kinds of stainless steels of different materials are arranged close to each other in the storage tank 1, and the close portion is always in the liquid phase below the lower limit water level LWL, Electrical corrosion occurs between the two stainless steels inside.

Furthermore, it is very troublesome that the following situation may occur in the actual storage tank 1. As described above, two kinds of stainless steels having different materials are arranged close to each other, and although the design is such that the close portion is always in the liquid phase portion below the lower limit water level LWL, actually assembling is performed. Water level L in storage tank 1
When the WL is set below the above-mentioned adjacent portion, the SUS444 stainless steel that should be in the liquid phase is exposed to the gas phase. For example, the sensor 171 of the elevated water tank 1B
If the length of the electrode rod used is incorrect,
For example, when the water level of A falls below the designed position, the lower limit water level LWL may be located below the adjacent part as described above. Then, since the water surface of the storage tank 1 fluctuates up and down, the SUS that should exist in the liquid phase part
444 stainless steel will be exposed at the draft. In this case, water droplets adhering to the inner surface of the SUS444 stainless steel easily absorb chlorine gas having a higher specific gravity than air stagnating in the lower part of the gaseous phase to become concentrated hydrochloric acid. A hole p is generated.

In addition, after the storage tank 1 is installed in a predetermined place, the lower limit water level LWL may be changed downward in order to increase the used capacity after several years have elapsed. It is thought that there are many cases in which various conditions are not understood. In this way, when the SUS444 stainless steel, which should be in the liquid phase, is exposed in the gas phase, water droplets adhering to the inner surface of the SUS444 stainless steel accumulate in the lower part in the gas phase as described above. The chlorine gas having a higher specific gravity than that of the air is easily absorbed to form a concentrated hydrochloric acid, and a pinhole p is generated.

Further, inside the storage tank 1, stay bolts for connecting opposed side walls, tri-stays for connecting between orthogonal side walls, between a side wall and a ceiling wall, or between a side wall and a bottom wall, and the like, and water level control are provided. Or alarm sensor 1
A large number of members made of stainless steel, such as 71 electrode rods, ball taps 121a, and bolt nuts, are attached. However, it is not possible to manufacture all of these stainless steel materials with SUS329J4L stainless steel having excellent corrosion resistance to hydrochloric acid. Near impossible. Therefore, water droplets attached to the surface of these stainless steel materials disposed in the gas phase portion of the storage tank 1 absorb chlorine gas and become hydrochloric acid, and the corrosion gradually proceeds.

On the other hand, in the case where a water spray hole (jet port) is provided in the gas phase portion of the storage tank 1 to wash out water droplets adhering to the ceiling wall and the side wall, it is difficult to make water spray toward the side wall and the ceiling wall uniform. is there. The water pressure is high near the base end (pump) of the pressure water pipe, the water pressure decreases as it goes to the end, and the amount of water spray increases on the inner wall near the water hole, and the water amount decreases as the distance from the water hole increases. Become. In particular, it is difficult for water to reach the corners of the storage tank 1 or the like. Therefore,
In order to spread water over the entire area of the side wall and ceiling wall corresponding to the gas phase portion of the storage tank 1, it is necessary to provide a large number of water spray holes. If there is a place where water spray does not spread, water droplets adhering there will always remain without being washed away, and the water droplets will absorb chlorine gas and become hydrochloric acid, generating pinholes p.

By forming a water film on the entire inner wall surface of the storage tank 1 corresponding to the gas phase,
It is almost impossible to prevent the chlorine gas from directly contacting the inner wall surface exposed on the water surface of the storage tank 1 (see Japanese Utility Model Publication No. 57-58147, column 4). Since it is difficult to make water spray uniform, it is difficult to form a water film on the entire inner wall surface. In addition, the water flowing down along the inner wall surface does not spread uniformly and falls while forming a film, but gathers at a portion that easily flows to form a flow of water. Therefore, in order to always form a water film on the entire inner wall surface corresponding to the gas phase portion of the storage tank 1, it is necessary to provide injection ports all over the entire inner wall surface. However, especially in the case of the stainless steel storage tank 1 having a large installation area, it is not realistic at all and it is difficult to provide a large number of injection ports all over the entire lower surface of the ceiling wall and the entire gas phase portion of the inner surface of the side wall. It can be said that.

Further, in order to uniformly spray and wash the entire side wall and the entire ceiling wall corresponding to the gaseous phase portion of the storage tank 1, a large amount of piping materials and mounting costs are required.

Also, aside from the design, in actuality, individual fountain conditions are different due to clogging of water holes, differences in performance of each water hole, differences in water pressure, and the like. In addition, it is very difficult to enter the storage tank and check the state of ejection.

In addition, when drinking water is stored in the storage tank, the water supply law enforcement regulations state that "the water tank should be cleaned once every year or less, and periodically". Mandatory. Therefore, it is necessary to periodically clean a set of pipes, water sprinkling holes, and pipe mounting members provided on the upper part of the storage tank, and the cleaning work becomes complicated and time-consuming. In addition, since the pipes and watering holes are located at a high position in the storage tank, the scaffolding is poor, the safety is difficult, and a reduction in workability cannot be avoided.

The present invention has been made in view of the above problems, and includes side walls, ceiling walls, stay bolts, tri-stays, sensors, and sensors corresponding to a gaseous phase part due to chlorine liberated in the gaseous phase part of a storage tank. An object of the present invention is to provide a corrosion prevention device for a stainless steel storage tank that can reliably prevent corrosion of a ball tap, a bolt and a nut.

[0039]

SUMMARY OF THE INVENTION The present invention provides a stainless steel storage tank having at least a side wall and a bottom wall made of stainless steel and having a ceiling wall capable of storing drinking water, and a storage tank provided at or near the storage tank. Mist generator, drinking water stored in the storage tank, or water guided from another water source as a mist by the mist generator almost continuously in the upper gas phase inside the storage tank By releasing the gas, corrosion of the stainless steel material in the gas phase is prevented.

Further, the present invention provides a stainless steel storage tank having at least a side wall and a bottom wall formed of stainless steel and having a ceiling wall capable of storing drinking water, and a mist generator attached to or near the storage tank. Drinking water stored in the storage tank, or water guided from another water source is almost continuously released as mist by the mist generator into the gas phase portion on the inner upper side of the storage tank. While absorbing the free chlorine released from the water into the fog, the fog having absorbed the free chlorine is discharged through a vent pipe and / or an overflow pipe having one end opening to the gas phase of the storage tank. Fog released almost continuously to water droplets attached to the surface of stainless steel material is aggregated into large water droplets,
By falling into the liquid phase, corrosion of the stainless steel material in the gas phase is prevented.

[0041]

Embodiments of the present invention will be described below with reference to the drawings.

The same members as those of the storage tank 1 shown in FIGS. 9 and 10 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows an apparatus for preventing corrosion of a stainless steel storage tank according to the present invention. This corrosion prevention device atomizes water from a stainless steel storage tank 1 for storing drinking water or drinking water stored in the storage tank 1 or water derived from another water source. And a mist generator 2 for discharging the mist to the section.

Here, the storage tank 1 is formed by welding a stainless steel plate to form a tank, and forming the tank by welding the stainless steel unit plate with the joining edge of the stainless steel unit plate facing the inside of the tank. Or a stainless steel unit plate with its joint edge facing the outside of the tank and the joint inside the tank welded to form a tank. Any structure may be used such that the side wall, the bottom wall, and the ceiling wall are connected by a nut to form a tank, and the side wall, the bottom wall, and the ceiling wall are assembled to form a tank.

As the mist generator 2, any device that can generate mist, such as an evaporator, a humidifier, or a device using the principle of mist blowing, can be used. Specific examples of the mist generator 2 include a sheathed heater evaporator, an electrode humidifier, an ultrasonic humidifier, and a spray humidifier.

As the spray humidifier, a one-fluid fine spray nozzle capable of spraying fine mist only by water pressure can be suitably used, and a fine mist spray can be provided by connecting a compressor to the spray nozzle portion. A possible two-fluid fine spray nozzle or the like can also be suitably employed.

Here, the fog refers to a state in which a large amount of minute water droplets are floating in the atmosphere, and also refers to such minute water droplets themselves. Therefore, a water drop falling due to its own weight is distinguished from a fog floating in the atmosphere.

The drinking water stored in the storage tank 1 or the water guided from another water source is turned into mist by the mist generator 2 and substantially continues to the gaseous phase portion in the upper inside of the storage tank 1. Is released. The fog generator 2 is connected to the control panel 17 and is automatically controlled.

It is preferable that the overflow pipe 15 is provided with a valve 151 as a shut-off portion so as to discharge only the overflowed water and to prevent the discharge of the mist that has become the hydrochloric acid by absorbing the free chlorine. However, when the storage tank 1 is installed outdoors, it is not always necessary to provide the valve 151.

When the storage tank 1 is installed in a closed space such as the inside of the building B, the other end of the ventilation pipe 19 connected to the gas phase of the storage tank 1 so that one end faces the other end, It is desirable to be located outside building B. That is,
The mist converted into hydrochloric acid by absorbing the free chlorine is discharged through the ventilation pipe 19, and the mist of the ventilation pipe 19 and other components are prevented from corroding the outer surface of the storage tank 1 and the equipment in the building B. It is preferable that the end opening be guided to the outside of the building B, and the mist converted into hydrochloric acid be released into the atmosphere. In addition, when releasing the mist converted into hydrochloric acid into the atmosphere adversely affects the surrounding environment, it is possible to capture the mist converted into hydrochloric acid by a mist capturing device as described later.

Next, the operation of such a corrosion prevention device will be described. Chlorine gas stays in the lower part of the gas phase of the storage tank 1. That is, the chlorine gas released from the tap water and / or sodium hypochlorite and diffused into the gas phase has a higher specific gravity than air, and thus stays in the lower part in the gas phase.

When the mist generator 2 operates, the drinking water stored in the storage tank 1 or water from another water source is guided to the mist generator 2 through the inflow pipe 21 to generate mist. You. This mist is discharged to the gas phase of the storage tank 1 through the supply pipe 22.

Then, the chlorine gas staying in the gas phase of the storage tank 1 rapidly and actively dissolves in the mist supplied into the gas phase.

Although the surface area of the individual fine water particles in the fog is small, the total surface area of the fine water particles of the fog which is released almost continuously into the gas phase portion of the storage tank 1 and exists in large quantities is Remarkably large. Therefore, the released chlorine gas easily dissolves in the fog.

The fine water particles of the mist that has become hydrochloric acid by absorbing the liberated chlorine gas are still mist, and therefore float freely in the gas phase of the storage tank 1. That is, the mist that has become hydrochloric acid fills the entire gas phase portion of the storage tank 1.

In the case where water from another water source is turned into mist, or in the case of the water receiving tank 1A in which tap water is replenished as soon as the water level is lowered, a large amount of mist is supplied to the gas phase portion of the storage tank 1. The mist that has absorbed the free chlorine in accordance with the supplied mist is discharged from the ventilation pipe 19 into the atmosphere.

On the other hand, the water level of the storage tank 1 rises and falls between the upper limit water level HWL and the lower limit water level LWL several times a day. That is, the volume of the gas phase portion in the storage tank 1 repeatedly increases and decreases several times a day. Therefore, every time the water level rises, the mist absorbing free chlorine is discharged from the ventilation pipe 19 in an amount corresponding to the decrease in the volume of the gas phase part due to the rise in the water level. Therefore, most of the free chlorine in the gas phase is discharged to the atmosphere without adhering to the inner wall surface of the storage tank 1.

Since such an operation is repeated a plurality of times a day, the chlorine gas does not stay in the lower part of the gas phase, and the mist absorbing the chlorine gas is discharged to the outside of the storage tank 1 sequentially.

The water vapor evaporated from the water surface in the storage tank 1 adheres to the side wall corresponding to the gas phase portion and the inner wall surface of the ceiling wall, and is cooled to form water droplets. When the water droplets come into contact with free chlorine, they absorb the chlorine gas and become hydrochloric acid. However, since the mist is continuously supplied to the gas phase portion of the storage tank 1, the water droplets absorb the mist that has come into contact with the water droplets one after another, grow large, and finally form droplets in the storage tank 1. Fall into the drinking water stored in the basin, or run down along the inner wall surface.

In this manner, the side wall, ceiling wall, stay bolt, tri-stay,
Water tanks attached to sensors, ball taps, bolts, nuts, etc. are stored as droplets before the chlorine concentration increases.
Can be dropped into the drinking water stored in the storage space, and the corrosion of the side wall and the ceiling wall can be reliably prevented.

Therefore, an austenitic ferritic duplex stainless steel called SUS329J4L having excellent corrosion resistance to hydrochloric acid is used for the side wall and the ceiling wall corresponding to the gas phase portion of the storage tank 1 and various members. No need.

That is, the stainless steel (for example, SUS32) which is more resistant to corrosion than the stainless steel (for example, SUS444) used for the side wall and the bottom wall of the liquid phase portion and which is very expensive (for example, SUS32).
9J4L) does not need to be used for the side wall and the ceiling wall corresponding to the gas phase portion of the storage tank 1, and the material of the side wall, the bottom wall and the ceiling wall of the storage tank 1 is the same stainless steel (for example, SU).
S444).

As described above, since it is possible to use the same material of stainless steel, it is possible to easily manage the inventory, to prevent the upper and lower parts from being erroneously mounted at the time of assembling, and to greatly reduce the overall cost. Can be.

Further, water droplets adhering to the surface of the side wall, ceiling wall, various members, etc. corresponding to the gas phase portion of the storage tank 1 become droplets before the chlorine concentration becomes high, and are added to the drinking water in the storage tank 1. Strictly speaking, part of free chlorine released from tap water and / or sodium hypochlorite returns to drinking water in the storage tank 1 because it is continuously absorbed,
The decrease in the chlorine concentration of drinking water can be suppressed at all. Further, a part of the mist is directly taken into the drinking water, and chlorine in the mist is reduced to the drinking water.

The drinking water stored in the storage tank 1
Alternatively, it is sufficient that the water introduced from another water source is substantially continuously released as a mist by the mist generator 2 into the gaseous phase portion on the upper inside of the storage tank 1 in a strict sense. It does not have to be released continuously. For example, the operation of the fog generator 2 may be stopped occasionally, or the operation and the stop may be repeated in a short cycle.

Hereinafter, a specific embodiment will be described with reference to FIGS. FIG. 2 shows a first embodiment of the present invention. Storage tank 1 of this embodiment
Is the elevated water tank 1B, the side wall and the ceiling wall of which are
It is formed by directing the joining edge 102 of the stainless steel unit plate 101 toward the inside of the tank and welding the joining portion inside the tank. And, between the opposing side walls, a stay 41 formed of a shaped steel such as an angle is stretched,
A column 42 for supporting the ceiling wall is provided between the bottom wall and the ceiling wall. In addition, the overflow pipe 15 is provided with a valve 151 as a shut-off unit that absorbs free chlorine and prevents discharge of mist that has become hydrochloric acid, and allows only overflow water to flow down. Is provided with an insect net 152. Further, the other end opening of the ventilation pipe 19 is guided to the outside of the building B, and the mist converted into hydrochloric acid is discharged into the atmosphere.

As the mist generator 2, a sheath heater type evaporator using a sheath heater 23 is adopted, and the drinking water stored in the storage tank 1 is guided and heated by the sheath heater 23 to remove steam. Has been made to occur. That is, the container 24 accommodating the sheathed heater 23 is installed adjacent to the storage tank 1, and the container 24 and the storage tank 1 are connected by the inflow pipe 21 provided with a normally open on-off valve 21 a. Container 24 and storage tank 1
Is connected by a supply pipe 22. The supply pipe 22 and the container 24 are covered with a heat insulating material 25.

Therefore, the drinking water stored in the storage tank 1 flows freely into the container 24 and the supply pipe 22 through the inflow pipe 21, and the water level of the storage tank 1 varies with the vertical movement. The water level of the supply pipe 22 fluctuates accordingly.
Here, when electricity is supplied to the sheath heater 23 by the control panel 17, the drinking water in the container 24 is heated to be steam, and steam having a specific gravity lower than that of water is supplied to the gas phase of the storage tank 1 through the supply pipe 22. Released.

As a result, the free chlorine floating in the gas phase of the storage tank 1 dissolves in the steam supplied to the gas phase,
The water vapor in which free chlorine is dissolved freely floats in the gas phase of the storage tank 1.

Here, since the volume of water vapor is larger than the volume of the original water (as can be seen from the fact that the vapor is ejected from the medicinal can), the volume of the water vapor is subtracted, and The resulting water vapor is discharged from the ventilation pipe 19 to the atmosphere.

Further, since the water level of the storage tank 1 rises and falls between the upper limit water level HWL and the lower limit water level LWL several times a day, the water level rises, and hydrochloric acid corresponding to the reduced volume of the gas phase is formed. The released steam is discharged from the ventilation pipe 19, and most of the free chlorine in the gas phase is discharged to the outside without adhering to the inner wall surface of the storage tank 1.

The water vapor evaporated from the water surface in the storage tank 1 adheres to the side walls and the inner wall surfaces of the ceiling wall corresponding to the gas phase portion and the surfaces of various members, and cools to water droplets. When such water droplets come into contact with free chlorine, they absorb the chlorine gas and become hydrochloric acid. However, fog generator 2
Since the mist (water vapor) generated by the (seed heater type evaporator) is continuously supplied into the gas phase portion of the storage tank 1, the water droplets absorb the mist that has come into contact with the water droplets one after another, and grow large. Eventually, the liquid drops and falls into the drinking water stored in the storage tank 1, or flows down along the inner wall surface.

Therefore, not only can the corrosion of the side wall and the ceiling wall corresponding to the gas phase portion of the storage tank 1 be reliably prevented, but also the corrosion of various members such as the stay 41 and the support column 42. Can be prevented.

In this embodiment, the sheath heater 2 is controlled by using a sensor 171 for controlling or warning the water level.
It is preferable to control them together. For example, when the water level drops abnormally below the lower limit water level LWL, control is performed to issue an alarm. At this time, if control is performed so as to stop supplying electricity to the sheathed heater 23,
Empty heating of the sheathed heater 23 can be prevented.

FIG. 3 shows a second embodiment of the present invention. The storage tank 1 of this embodiment includes a high water tank 1B.
And the side wall and the bottom wall are made of a stainless steel unit plate 10.
One of the joining edges 102 is directed outward of the tank, a packing 103 is sandwiched between the opposed joining edges 102, fastened with bolts and nuts, and connected in order. For the ceiling wall, the joining edge 1 of the unit plate 101 is used.
02 is directed inward of the tank, fastened by bolts and nuts, and connected in order.

Further, a stay bolt 43 is stretched between the opposed side walls, and a column 45 for supporting the beam 44 is erected between the beam 44 fixed to the ceiling wall and the bottom wall. .

The unit plate 101 adjacent to the upper and lower sides of the side wall
An L-shaped reinforcing angle 46 is provided along the joining edge 102 so as to strongly reinforce the opposed joining edge 102 so as not to be bent by water pressure.
Are penetrated through the side wall in a watertight manner and are connected to a reinforcing plate 461 attached to the reinforcing angle 46. Also,
A tri-stay 47 is connected between the side wall and the bottom wall.

As the mist generator 2, a sheathed heater type evaporator using a sheathed heater 23 is employed as in the case of the above-described first embodiment, and guides the drinking water stored in the storage tank 1. The steam is heated by a sheath heater 23 to generate steam. However,
In this embodiment, a container 24 for accommodating the sheathed heater 23 is installed at a position lower than the lower limit water level LWL inside the storage tank 1 and is fixed to the side wall. And between the inside of the storage tank 1 and the container 24,
A normally open on-off valve 21a is connected by a U-shaped inflow pipe 21 disposed outside the storage tank 1, and a container 2
The supply pipe 22 whose one end is connected to the storage tank 1 is connected to the storage tank 1 such that the other end of the supply pipe 22 is located in the gas phase of the storage tank 1.
It is erected inside. The periphery of the connecting portion where the sheathed heater 23 and the container 24 are attached to the side wall is covered with a heat insulating material 25.

Therefore, the drinking water stored in the storage tank 1 freely flows into the container 24 and the supply pipe 22 through the inflow pipe 21, and changes in the water level of the storage tank 1 up and down. The water level of the supply pipe 22 fluctuates accordingly.
Here, when electricity is supplied to the sheath heater 23 by the control panel 17, the drinking water in the container 24 is heated to be steam, and steam having a specific gravity lower than that of water is supplied to the gas phase of the storage tank 1 through the supply pipe 22. Released.

As a result, the free chlorine floating in the gas phase of the storage tank 1 dissolves in the steam supplied to the gas phase,
The water vapor in which free chlorine is dissolved freely floats in the gas phase of the storage tank 1.

Here, steam which has been converted into hydrochloric acid corresponding to the volume increased from the original water before being turned into steam is discharged from the ventilation pipe 19 into the atmosphere.

Since the water surface rises and falls several times a day,
The water vapor that has become hydrochloric acid corresponding to the decrease in the volume of the gas phase part due to the rise of the water surface is discharged from the vent pipe 19, and most of the free chlorine in the gas phase part adheres to the inner wall surface of the storage tank 1. Emitted into the atmosphere without any

The water vapor evaporated from the water surface in the storage tank 1 adheres to the side wall corresponding to the gas phase portion, the inner wall surface of the ceiling wall, and the surface of various members, and cools to water droplets. Although such water droplets also absorb free chlorine and become hydrochloric acid, the water droplets successively coagulate water vapor that is continuously supplied, grow large, and become droplets before the chlorine concentration becomes high. Drops into drinking water or runs down the inner wall.

Therefore, not only can the corrosion of the side wall and the ceiling wall of the gas phase portion of the storage tank 1 be reliably prevented, but also the corrosion of the stay bolt 43, the support 45, the tri-stay 47, and the like. Can be prevented.

FIG. 4 shows a third embodiment of the present invention. The storage tank 1 of this embodiment is a water receiving tank 1A, and a side wall and a bottom wall are made of a stainless steel unit plate 101.
Is formed by directing the joining edge 102 of the tank toward the outside of the tank and welding the joint portion inside the tank. The ceiling wall is formed by turning the joining edge 102 of the stainless steel unit plate 101 toward the inside of the tank and welding the joint inside the tank.

[0086] In such a storage tank 1, the inner surfaces of the side wall and the bottom wall become smooth. Therefore, not only is it easy to clean and the cleaning operation time is shortened, but also it is possible to clean more cleanly and it is hygienic. Moreover, not only is it convenient to store tap water, but also the storage portion of the storage tank 1 is smooth, so that it can be used in a sanitary manner when it is diverted for storing various foods.

When forming the side wall and the bottom wall of the storage tank 1, the joining edges 102 of the adjacent unit plates 101 are fastened with bolts and nuts and fixed so that the joining edges 102, 102 do not shift during the welding operation. Then, if the inner surface side of the storage tank 1 is welded, workability is good. The bolt and nut may be left attached or removed after welding. Further, the outer surface side of the storage tank 1, that is, the joining edge 1
By temporarily fixing the end faces of 02 and 102 by welding in place, it is possible to replace bolt and nut fastening.

In this embodiment, the introduction tube 1
A water-absorbing silencer 5 is provided immediately below the base end opening 2 to prevent the occurrence of water impact noise when water is supplied. The wave-damping device 5 is provided upright along the side wall in the storage tank 1 and is detachably fixed by a band 54 or the like, and is held in the outer tube 51 and is formed of a perforated plate or the like. And a filler 53 such as a Raschig ring filled in the inner cylinder 52. Introductory pipe 1
When tap water is supplied into the water receiving tank 1A from the tank 2, the tap water immediately collides with the filler 53 accommodated in the inner cylinder 52 and is diffused, the falling speed is attenuated and the tap water falls, and the tap water is gently dropped. The water reaches the water surface in the inner cylinder 52. For this reason, the impact sound of tap water hitting the water surface is suppressed smaller than when tap water discharged from the introduction pipe 12 falls at a stretch and collides with the water surface in the water receiving tank 1A.

Further, since the upper end of the inner cylinder 52 is located above the upper limit water level HWL of the water receiving tank 1A, the introduction pipe 1
2 can suppress the ripple of the water surface in the water receiving tank 1A due to the inflow of the tap water from the ball tap 12 as a result.
1a and the water surface control by the electrode rod of the sensor 171 can be accurately performed. In addition, if a large wave is generated when tap water is introduced, a large amount of free chlorine is generated and the chlorine concentration in the liquid phase decreases, and chlorine gas accumulates in the gas phase. In order to maintain the sterilization effect by performing the above operation, it is preferable to provide the wavebreak silencer 5.

On the other hand, the mist generator 2 is constituted by installing a plurality of one-fluid fine spray nozzles (spray humidifiers) 27 in the gas phase. That is, a water supply pump 26 is installed outside the storage tank 1, a normally open on-off valve 21 a is provided, and the inlet pipe 21 provided with a filter 21 c at one end opening located in the liquid phase portion of the storage tank 1 is provided. The end opening is connected to the suction port of the water supply pump 26, and the supply pipe 22 is provided between the discharge port of the water supply pump 26 and the gas phase of the storage tank 1. The supply pipe 22 is branched into a plurality of pipes, and a one-fluid fine spray nozzle 27 is provided at the tip of each branch pipe 221.

Here, a plurality of one-fluid fine sprays are sprayed so that the fine mist sprayed from the one-fluid fine spray nozzle 27 circulates on the water surface along the inner surface of the side wall corresponding to the gas phase portion of the storage tank 1. With the nozzles 27 at appropriate intervals, almost horizontally,
Moreover, it is preferable that the spray nozzle 27 is installed so that the direction of the spray port is in the same clockwise direction or in the opposite direction.

In this embodiment, the one-fluid fine spray nozzle 27 which can obtain fine mist only by water pressure is used. However, by connecting the spray nozzle portion and the compressor, it is possible to spray fine mist. A mist can be circulated in the same manner as described above by employing a fluid fine spray nozzle. However, when a two-fluid fine spray nozzle is used, a compressor as an air source is required as described later.

Further, in this embodiment, an example is shown in which the inside of the storage tank 1 is not divided into a plurality of chambers by a partition wall, a rectifying wall, or the like. However, as shown in FIG. When divided into a plurality of chambers by the wall S or the rectification wall T, the supply pipe 22 connected to the water supply pump 26 is branched into a plurality of pipes, and a branch pipe 221 is provided in each chamber. One-fluid fine spray nozzle 2 at the end of pipe 221
7 or a two-fluid fine spray nozzle may be provided to spray fine mist into each chamber.

Therefore, when the water supply pump 26 is operated by the control panel 17, the drinking water in the storage tank 1 is sucked by the water supply pump 26 and supplied to each one-fluid fine spray nozzle 27 via the supply pipe 22 and the branch pipe 221. Then, the mist is made into fine mist by the one-fluid fine spray nozzle 27 and ejected into the gas phase. The sprayed mist is stored in the storage tank 1
Circulates on the water surface along the inner surface of the side wall corresponding to the gas phase portion.

Then, the chlorine gas having a higher specific gravity than the air stays in the lower portion of the gas phase in the storage tank 1, so that the fine mist injected from the one-fluid fine spray nozzle 27 is Chlorine gas staying in the vicinity of the side wall corresponding to the lower portion is very easily absorbed and easily converted into hydrochloric acid.
Therefore, the amount of chlorine gas floating near the side wall corresponding to the lower part of the gas phase is reduced. Further, water droplets adhering to the vicinity of the side wall corresponding to the lower part of the gaseous phase portion tend to absorb circulating fine mist one after another and become large water droplets. Therefore, water droplets attached to the vicinity of the side wall corresponding to the lower portion of the gas phase portion grow rapidly and large, and finally fall as drinking water into the drinking water stored in the storage tank 1. Runs down the wall. Therefore, it is necessary to prevent the water droplets attached to the draft portion between the upper limit water level HWL and the lower limit water level LWL and the side wall in the vicinity thereof from absorbing free chlorine to become high-concentration hydrochloric acid, thereby preventing generation of many pinholes p. Can be.

Further, the tap water is supplied from the introduction pipe 12 by opening the ball tap 121a to the extent that the drinking water in the water receiving tank 1A becomes fog and reduced, so that the water level of the water receiving tank 1A hardly fluctuates. Fog corresponding to the amount of the mist generated by the mist generator 2 released into the gas phase is discharged from the ventilation pipe 19.

The mist that has absorbed free chlorine floating in the gas phase of the storage tank 1 and has become hydrochloric acid floats freely in the gas phase, so that the water surface of the storage tank 1 fluctuates. When ascending, the gas phase is discharged from the vent pipe 19 by an amount corresponding to the reduced volume.

As a result, most of the free chlorine is discharged to the atmosphere without adhering to the inner wall surface of the storage tank 1.

FIG. 6 shows a fourth embodiment of the present invention. The storage tank 1 of this embodiment includes a high water tank 1B.
In this case, a stainless steel plate is welded to form a cylindrical tank. Such an integrated tank also has the advantage that the inner surface is substantially smooth and easy to clean.

Further, a trap 153 bent in a U-shape is formed in the overflow pipe 15 as a cutoff portion in order to prevent discharge of free chlorine and to allow only overflow water to flow down. In the trap 153 of the overflow pipe 15, dew condensation water and a part of the overflow when the water level exceeds the upper limit water level HWL are stored. Preferably, a level gauge 154 is provided to check the level of the sealed water stored in the trap 153, and a supply pipe 155 is provided so that the sealed water can be appropriately supplied as needed.

Further, the opening at the other end of the ventilation pipe 19 is guided to the outside of the building B, so that the mist converted into hydrochloric acid is discharged into the atmosphere.

On the other hand, the mist generator 2 is constructed by installing one or a plurality of two-fluid fine spray nozzles (spray humidifier) 28 in the gas phase. That is, a control unit 29 having a built-in water supply pump is installed outside the storage tank 1, and an opening / closing valve is provided between the liquid unit of the storage tank 1 and the control unit 29, and between another water source and the control unit 29. They are connected by an inflow pipe 21 provided with an on-off valve 21a and an on-off valve 21b. Further, between the control unit 29 and the two-fluid fine spray nozzle 28 disposed in the gas phase of the storage tank 1, a spray unit 281 for removing the water pressure of the water supply pump and storing the water is provided. It is connected by a supply pipe 22. Further, the two-fluid fine spray nozzle 28 and the control unit 29 are connected by an air pipe 31, and the control unit 29 is provided with a compressor 30 as an air source. Then, the air amount and the air pressure of the compressed air fed from the compressor 30 are adjusted by the control unit 29 so that the injection amount and the injection pressure of the mist ejected from the two-fluid fine spray nozzle 28 are properly maintained. ing. In addition, when tap water is used as another water source (when drinking water in the storage tank 1 is not used), there is no need to attach a water supply pump to the control unit 29 because tap water has a water pressure.

Therefore, when the control unit 29 operates the compressor 30 and a water supply pump (not shown, if a tap water is used as another water source), the drinking water or other water source in the storage tank 1 is activated. The supplied water enters the control unit 29 through the inflow pipe 21 and passes through the supply pipe 22 to the spray unit 28.
1 is supplied. On the other hand, the compressed air fed from the compressor 30 is supplied to the two-fluid fine spray nozzle 28 via the air pipe 31. Therefore, water in the spray unit 281 is sucked up by the principle of spraying, turned into fine mist by the two-fluid fine spray nozzle 28, and continuously jetted into the gas phase of the storage tank 1.

As a result, the free chlorine floating in the gas phase of the storage tank 1 is dissolved in the mist jetted into the gas phase, and the mist in which the free chlorine is dissolved freely floats in the gas phase of the storage tank 1. I do. Since the water level of the storage tank 1 rises and falls between the upper limit water level HWL and the lower limit water level LWL several times a day, the mist which has become hydrochloric acid corresponding to the rise of the water level and the reduction of the volume of the gas phase is formed in the vent pipe. Most of the free chlorine in the gaseous phase part is discharged to the outside without adhering to the inner wall surface of the storage tank 1.

Further, although some free chlorine dissolves in water droplets adhering to the side wall and the inner wall surface of the ceiling wall corresponding to the gas phase portion of the storage tank 1, mist is continuously supplied to the gas phase portion of the storage tank 1. As a result, the water droplets fall into drinking water stored in the storage tank 1 as a droplet before the chlorine concentration increases, or flow down along the inner wall surface. For this reason,
Corrosion of the side wall and the ceiling wall of the gas phase portion of the storage tank 1 can be reliably prevented.

FIG. 7 shows a fifth embodiment of the present invention. The storage tank 1 of this embodiment is a water receiving tank 1A, the side wall of which is formed by directing a joining edge 102 of a stainless steel unit plate 101 to the outside of the tank and welding a joint portion inside the tank. The bottom wall has a flat plate shape. The ceiling wall is made of stainless steel or FR
It is formed by turning the joining edge 102 of the plastic unit plate 101 such as P toward the inside of the tank, sandwiching a packing between the opposed joining edges, and fastening with a bolt and nut. Note that a structure in which an outer frame reinforcing member 48 is provided outside the side wall and the ceiling wall of the storage tank 1 is illustrated.

The overflow pipe 15 penetrates from the outside to the inside of the side wall of the storage tank 1 at the position of the overflow water level OFL, and its one end opening is located below the lower limit water level LWL of the storage tank 1. It is open. Therefore, when the water level of the storage tank 1 rises and reaches the overflow water level OFL, the lower drinking water stored in the storage tank 1 is discharged. Therefore, the mist containing free chlorine is not discharged from the overflow pipe 15.

A siphon prevention pipe 15a communicating with the atmosphere is provided at an upper portion outside the side wall of the overflow pipe 15.
Consideration is made so that the drinking water in the storage tank 1 is not discharged by the siphon phenomenon. If the siphon prevention tube 15a
If the overflow water overflows beyond the overflow water level OFL for any reason and flows down the overflow pipe 15 without any gap, the drinking water in the water receiving tank 1A is opened from one end of the overflow pipe 15 to the other end. The siphon phenomenon occurs in which the water level in the water receiving tank 1A is continuously discharged to lower the water level. However, if a siphon prevention pipe 15a communicating with the atmosphere is provided above the overflow pipe 15, the occurrence of the siphon phenomenon can be prevented.

At the end of the ventilation pipe 19, the fog catcher 2
0 is connected. This mist catcher 20 is a cylindrical body 20
1, the capturing material 202, which is composed of the capturing material 202 and the support material 203, does not hinder the ventilation of the net, the fiber, the Raschig ring and the like filled in the cylindrical body 201,
It is supported by a support member 203 composed of a perforated plate, a net, a crosspiece, and the like. Therefore, the mist containing free chlorine discharged from the gas phase part of the storage tank 1 is trapped in the trapping material 2 in the mist trap 20.
Dew forms while passing through the gap No. 02, and is collected as dew water containing chlorine. Therefore, since the mist containing hydrochloric acid containing free chlorine is not discharged into the atmosphere, corrosion of equipment inside and outside the building B is prevented. In addition, although the case where the fog catcher 20 is disposed inside the building B is illustrated, it may be disposed outside the building B.

On the other hand, although not shown, the fog generator may employ any one described above.

The storage tank 1 is operated by a fog generator (not shown).
The mist supplied to the gaseous phase portion absorbs free chlorine floating in the gaseous phase portion to become hydrochloric acid, and floats freely in the gaseous phase portion.
Further, since the water level of the storage tank 1 fluctuates a plurality of times a day, the mist of hydrochloric acid corresponding to the rise in the water level and the reduction in the volume of the gas phase is discharged from the ventilation pipe 19. Therefore,
Most of the free chlorine in the gas phase is discharged from the vent pipe 19 without adhering to the inner wall surface of the storage tank 1. Also,
The mist in which the free chlorine is dissolved is captured by a mist capturing device 20 provided at the tip opening of the ventilation pipe 19, and is recovered as dew water containing chlorine.

Although free chlorine also dissolves in water droplets adhering to the side wall corresponding to the gaseous phase portion of the storage tank 1 and the inner wall surface of the ceiling wall, since the storage tank 1 is continuously supplied with mist, the water droplets are continuously discharged. Absorbs the supplied mist and grows large, eventually forming droplets, and falls into drinking water stored in the storage tank 1 before the chlorine concentration in the water drops increases, or along the inner wall surface. run down. Therefore, corrosion of the side wall and the ceiling wall of the gas phase portion of the storage tank 1 can be reliably prevented.

FIG. 8 shows a sixth embodiment of the present invention. The storage tank 1 of this embodiment includes a high water tank 1B.
The side wall is formed by directing the joining edge 102 of the unit plate 101 made of stainless steel to the outside of the tank and welding the joining portion inside the tank.

The overflow pipe 15, like the overflow pipe 15 shown in FIG. 7, is guided from the outside to the inside of the side wall of the storage tank 1 at the position of the overflow water level OFL. It is located below the lower limit water level LWL of 1 and is open. Therefore, when the water level of the storage tank 1 rises and reaches the overflow water level OFL, the lower drinking water stored in the storage tank 1 is discharged. Therefore, the mist containing free chlorine is not discharged from the overflow pipe 15. In this embodiment, a small hole 15b for preventing a siphon phenomenon communicating with the atmosphere is formed above the overflow pipe 15.

Further, a fog catcher 20 is attached to the tip opening of the ventilation pipe 19 which penetrates the outer wall of the building B and is led to the outside. The mist catcher 20 is configured by alternately projecting a plurality of baffle plates 205 inside the cylinder 204, and when the mist containing free chlorine passes through the inside of the cylinder 204, the baffle plate 205 The route is changed by 205 to cause dew condensation, and is collected as dew water containing chlorine.
Also in this embodiment, the mist in which the free chlorine is dissolved is not discharged to the atmosphere, and it is possible to prevent the equipment inside and outside the building B from corroding.

On the other hand, although the fog generator is not shown, any one described above may be employed.

The storage tank 1 is operated by a fog generator (not shown).
The mist supplied to the gaseous phase portion absorbs free chlorine floating in the gaseous phase portion to become hydrochloric acid, and floats freely in the gaseous phase portion.
Further, since the water level of the storage tank 1 fluctuates a plurality of times a day, the mist of hydrochloric acid corresponding to the rise in the water level and the reduction in the volume of the gas phase is discharged from the ventilation pipe 19. Therefore,
Most of the free chlorine in the gas phase is discharged from the vent pipe 19 without adhering to the inner wall surface of the storage tank 1. Also,
The mist in which the free chlorine is dissolved is captured by a mist capturing device 20 provided at the tip opening of the ventilation pipe 19, and is recovered as dew water containing chlorine.

Although free chlorine also dissolves in water droplets adhering to the side wall corresponding to the gas phase portion of the storage tank 1 and the inner wall surface of the ceiling wall, since the mist is continuously supplied to the storage tank 1, the water droplets are supplied. Absorbs the supplied mist and grows large, eventually forming droplets, and falls into drinking water stored in the storage tank 1 before the chlorine concentration in the water drops increases, or along the inner wall surface. run down. Therefore, corrosion of the side wall and the ceiling wall of the gas phase portion of the storage tank 1 can be reliably prevented.

[0119]

As described above, according to the present invention, the fine mist almost continuously discharged into the gas phase of the storage tank is heavier than the air stagnating in the lower part of the gas phase of the storage tank. Absorbs free chlorine and allows hydrochloric acid mist to float freely in the gas phase of the storage tank, taking advantage of the fact that the water level of the storage tank fluctuates several times a day and the volume of the gas phase increases and decreases. do it,
When the volume of the gas phase decreases, the mist that has become hydrochloric acid can be discharged out of the storage tank. In addition, water droplets attached to the side wall and the ceiling wall corresponding to the gas phase portion of the storage tank absorb the mist released almost continuously and grow into droplets, and fall into the drinking water stored in the storage tank, Or, the water drops absorb along the inner wall surface, so that the water droplets absorb free chlorine and become hydrochloric acid, and the corrosiveness does not gradually increase, and the side wall and ceiling wall corresponding to the gas phase of the storage tank corrode. Can be reliably prevented.

As a result, even in the gas phase in which free chlorine stays, the stainless steel of the same material as the stainless steel used in the liquid phase, for example, the less expensive SUS444, without using expensive “super stainless steel”. It is possible to use stainless steel. In addition, since it is not necessary to use two types of stainless steel properly, inventory management becomes easy, and troubles during production, inventory, and shipping can be prevented. In addition, when corroded up and down during the assembly work, or when the actual water level of the tank is lower than the designed water level and the stainless steel that should be in the liquid phase is exposed to the gas phase, the conventional corrosion However, according to the present invention, even if such a mistake occurs, it is safe because it does not corrode. In addition, electric corrosion does not occur by disposing the unit plates made of two types of stainless steel adjacent to each other in the liquid phase portion. In addition, water droplets adhering to the surface of the side wall, ceiling wall, and various members corresponding to the gas phase of the storage tank become droplets before the chlorine concentration becomes high and are continuously absorbed by the drinking water in the storage tank. Strictly speaking, part of the free chlorine released from the tap water and / or sodium hypochlorite will return to the drinking water in the storage tank again, and the decrease in the chlorine concentration of the drinking water will be somewhat reduced. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating the principle of a storage tank corrosion prevention device according to the present invention.

FIG. 2 is a sectional view showing a first embodiment of a storage tank corrosion prevention device of the present invention.

FIG. 3 is a sectional view showing a second embodiment of the storage tank corrosion prevention device of the present invention.

FIG. 4 is a perspective view showing a third embodiment of a storage tank corrosion prevention device according to the present invention, partially cut away.

FIG. 5 is a sectional view showing another embodiment of the storage tank corrosion prevention device of the present invention.

FIG. 6 is a perspective view, partially broken away, of a fourth embodiment of the storage tank corrosion prevention device of the present invention.

FIG. 7 is a cross-sectional view of a storage tank corrosion prevention device according to a fifth embodiment of the present invention with a part thereof being omitted;

FIG. 8 is a cross-sectional view showing a sixth embodiment of a storage tank corrosion prevention device according to the present invention, with a part thereof being omitted;

FIG. 9 is a schematic diagram illustrating a water receiving tank and an elevated water tank that are storage tanks.

FIG. 10 is a schematic diagram illustrating the principle of the occurrence of corrosion in the storage tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage tank 1A Water receiving tank 1B Elevated water tank 12 Inlet pipe 13 Pumping pipe 15 Flood pipe 151 Valve (blocking part) 153 Trap (blocking part) 171 Sensor 19 Vent pipe 20 Fog catcher 2 Fog generator 23 Seeds heater 27 One fluid Fine spray nozzle (spray humidifier) 28 Two-fluid fine spray nozzle (spray humidifier)

Claims (5)

[Claims] 1. A storage tank made of stainless steel having at least a side wall and a bottom wall made of stainless steel and having a ceiling wall capable of storing drinking water, and a mist generator attached to or near the storage tank. The drinking water stored in the storage tank, or the water guided from another water source is almost continuously discharged as mist by the mist generator into the upper gas phase inside the storage tank, whereby the gas phase A corrosion prevention device for a stainless steel storage tank, which prevents corrosion of stainless steel materials. 2. A storage tank made of stainless steel having at least a side wall and a bottom wall made of stainless steel and having a ceiling wall capable of storing drinking water, and a mist generator attached to or near the storage tank. The drinking water stored in the storage tank, or water guided from another water source, was almost continuously released as mist by the mist generator into the upper gas phase inside the storage tank, and was released from the drinking water. The free chlorine is absorbed by the mist, and the mist absorbing the free chlorine is discharged through a vent pipe and / or an overflow pipe whose one end faces the gas phase of the storage tank, while the surface of the stainless steel material in the gas phase It is characterized by preventing the corrosion of stainless steel material in the gas phase by dropping into the liquid phase by agglomerating the mist released almost continuously to the water droplets adhering to the liquid phase. Corrosion prevention device for stainless steel storage tanks. 3. The corrosion prevention device for a stainless steel storage tank according to claim 2, wherein the other end opening of the ventilation pipe is located outside a building. 4. The corrosion prevention device for a stainless steel storage tank according to claim 2, wherein a fog catcher is connected to the other end opening of the ventilation pipe. 5. The corrosion prevention device for a stainless steel storage tank according to claim 2, wherein the overflow pipe is provided with a cut-off portion for preventing flow of mist and allowing passage of the overflow.