JPH0885891A - Cleaning method for concentrated free chlorine water generation system for sterilization - Google Patents

Abstract

(57) [Summary] [Purpose] An object of the present invention is to provide a cleaning method for a concentrated free chlorine water generation system for sterilization, which can prevent rust generation, is easy to maintain, and is easy to perform liquid treatment after cleaning. It is what According to the cleaning method of the sterilized concentrated free chlorine water producing system of the present invention, after the concentrated free chlorine water is discharged from the discharge passage 11, a second predetermined amount of washing water is supplied to the sterilized concentrated free chlorine water generating system. It is characterized in that after supplying and continuing the circulation cleaning through the circulation path 15, the switching means 6 is switched to discharge almost the entire amount of the second predetermined amount of cleaning water from the discharge path 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a concentrated free chlorine water producing system for sterilization used for sterilizing Legionella spp. Generated in a cooling water cooling tower or the like.

[0002]

2. Description of the Related Art In recent years, the degree of airtightness of buildings has become higher with the development and upgrading of the residential environment, and many efforts have been made to make indoor air conditioning comfortable. On the other hand, large-scale air conditioning has become widespread due to the increase in the number of houses and offices, and it has been effective in ventilation and cooling in the room. By the way, a normal cooling system is composed of a refrigerator that circulates the cooled refrigerant in a cooling coil and a cooling tower that supplies cooling water to the refrigerator. In the cooling tower, the cooling water that has absorbed the heat of the refrigerant in the heat exchanger is dropped from the water supply pipe inside the cooling tower and brought into contact with the air to form a spray, and the heat of vaporization at that time absorbs the heat of the cooling water and the temperature of the cooling water. Is to lower. By the way, this cooling tower is often installed outdoors and is exposed to the outside temperature, and it is operated in hot and humid conditions especially in summer. In such high temperature and high humidity, many bacteria easily propagate, which is unhygienic and also a source of environmental pollution. Particularly in recent years, a mass outbreak of diseases such as pneumonia caused by Legionella spp. Which have occurred in cooling towers has become a major social problem. The Legionella spp.generated in the cooling tower become an aerosol with cooling water and widely disperse in the atmosphere, or are sucked from the outside air intake for air conditioning installed nearby and dispersed in each room and collectively. It causes disease. In order to prevent this, a general method is to regularly clean the inside of the cooling tower and exchange all the cooling water to wash and remove Legionella spp. However, this method is complicated, and there is a problem that the removal of the Legionella bacterium is not sufficient and the disposal of the waste liquid containing the Legionella bacterium costs. In order to solve these problems, there is a method of manually adding a chemical such as acid or hydrogen peroxide to the cooling liquid to sterilize and wash Legionella spp. However, this method directly handles chemicals such as acid and hydrogen peroxide, which is not only a safety problem but also complicated. Further, there is a method in which a chemical storage container for acid, hydrogen peroxide, etc. is provided side by side with the cooling tower. That is, in this method, a drug injection pump is provided in the drug storage container, and a predetermined amount of the drug is injected into the cooling tower according to the flow rate cumulative signal of the cooling water to sterilize and wash Legionella spp.

[0003]

However, the method of injecting a predetermined amount of the drug into the cooling tower by providing the drug injection pump in the drug storage container and the flow rate cumulative signal of the cooling water causes the drug to oxidize and corrode the storage container. However, there is a problem in that a rustproof storage container or the like must be used, a lot of time is required for maintenance, and the life of the cleaning equipment is short.

Therefore, the present invention solves the above-mentioned problems of the prior art. It can prevent the generation of rust, can be easily maintained, and can be treated with a liquid after washing to produce concentrated free chlorine water for sterilization. It is an object of the present invention to provide a method for cleaning a system.

[0005]

In order to achieve the above object, the method for cleaning a concentrated free chlorine water producing system for sterilization according to the present invention comprises a second method after discharging concentrated free chlorine water from a discharge passage.
A predetermined amount of washing water is supplied to the concentrated free chlorine water generation system for sterilization, and after continuing the circulation washing through the circulation passage, the switching means is changed over so that almost the entire amount of the second prescribed amount of washing water is discharged from the discharge passage. It is characterized by discharging.

[0006]

The cleaning method for the sterilized concentrated free chlorine water producing system of the present invention is such that after the concentrated sterilized concentrated free chlorine water is generated, it is discharged at one time and a second predetermined amount of cleaning water is newly supplied. Since it is circulated, sufficient washing can be carried out at each concentration. Moreover, the system in which corrosion is likely to proceed due to the concentration can be restored to the initial state each time the concentration is increased. Further, since the cleaning water after cleaning is discharged to the discharge path after circulating cleaning in the circulation path, the liquid treatment after cleaning can be facilitated.

[0007]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory diagram of a method for cleaning a concentrated free chlorine water producing system for sterilization in one embodiment of the present invention. FIG.
In the above, 1 is a water tank for storing raw water or concentrated free chlorine water for sterilization. This raw water is introduced to produce free chlorine water and also to be used as washing water. 2 is a chloride aqueous solution tank for adding chloride containing chlorine components such as sodium chloride to raw water by a salt water pump 5, 3 is an electrolytic cell in which electrodes C and D are provided inside, and 4 is a circulation path 15 for supplying raw water. A pump for circulation, 6 is a circulation path 15
And the circulation path 15 connecting or closing the discharge path 11
Flow path switching means for switching which to select,
Reference numeral 7 is a raw water electromagnetic valve for adjusting the inflow amount of raw water, 8 is an inlet for tap water or ground water, which is raw water, 9 is a high water level sensor installed in the water tank 1 to detect the amount of stored raw water, and 10 is the water tank 1
A low water level sensor installed on the ground to detect the minimum amount of raw water stored, 1
A cooling tower 2 is sterilized by mixing the concentrated free chlorine water for sterilization discharged from the discharge passage 11 into the cooling chamber. The low water level sensor 10 detects concentrated free chlorine water for residual sterilization and washing water, but the lower the minimum storage amount, the more preferable. A cleaning liquid is also introduced into the cooling tower 12 as described later. 13 is a salt water solenoid valve for adjusting the inflow amount of the chloride aqueous solution into the water storage tank 1. 14 is a sterilizer by controlling the electrodes C, D, the pump 4, the flow path switching means 6, the raw water solenoid valve 7 and the salt water solenoid valve 13. This is a control unit for generating concentrated free chlorine water for cleaning and cleaning the concentrated free chlorine water generating system for sterilization.

Here, the capacity of the water storage tank 1 is preferably about 1/40 to 1/50 of the amount of cooling water circulating in the cooling tower 12. With such a capacity, free chlorine water can be generated and concentrated in a short time, and oxidative corrosion of the generation system can be suppressed. In this embodiment, the cooling water of the cooling tower 12 is set to 20
The volume of the water storage tank 1 is 00 liters and 50 liters. At this time, the time required for the concentrated free chlorine water generation process described later is about 5 hours, the discharge process time to the cooling tower 12 is about 5 minutes, and the cleaning process is about 1 hour.

By the way, as described above, the sterilization and cleaning is completed in about 1 hour, but the concentrated free chlorine water producing system for sterilization may be suspended until the next discharge to the cooling tower 12 for about 1 week. It is commonly done. Therefore, it is important to wash as soon as possible immediately after the production process. Therefore, the concentrated free chlorine water producing process for sterilization will be described first, and then the discharging process and the cleaning process will be described.

The raw water solenoid valve 7 is opened by a signal from the control unit 14.
Raw water flows into the water storage tank 1 through the inflow port 8. Water tank 1
When the water level sensor 9 installed in the
The magnetic valve 7 is closed and the supply of raw water is stopped. This practice
In the case of the example, the first predetermined amount of raw water stored in the water tank 1 is 50
Let it be liters. Next, open the salt water solenoid valve 13 and pump the salt water pump.
5 from the chloride aqueous solution tank 2 to 10% concentration of sodium chloride
Add a portion of the aqueous solution of arium to the raw water in the water tank 1 to
It produces a chlorine concentration of 00 ppm. Sodium chloride water soluble
The raw water added with the liquid is sucked by the pump 4, and the flow path is switched.
It is sent to the means 6. The flow path switching means 6 is, for example, three-way
It is good to use a valve, etc. to circulate the raw water in the circulation path 15.
The discharge passage 11 to prevent the raw water from being discharged.
Have been. Circulation path 1 via this flow path switching means 6
Raw water added with sodium chloride from 5 is poured into the electrolyzer 3.
To be watered. Pump 4 has a suction capacity of 10 l / min
are doing. The raw water poured into the electrolyzer 3 is not shown in the flow chart.
-When the specified amount of water is detected by the switch detection, control
A voltage is applied to the electrodes C and D from the part 14 to start electrolysis.
To be done. Free chlorine (C
l², HOCl, OCl ^-The raw water containing
It will be returned to the water tank 1 from 15. More professionals
The free chlorine concentration compared to the first raw water with the process as one cycle
The raw water whose temperature has risen is stored in the water tank 1. Pump 4
Continuously pouring raw water from the water storage tank 1 into the electrolysis tank 3 for electrolysis
In tank 3, voltage is continuously applied to electrodes C and D for electrolysis.
Because of this, the water flowing back to the water tank 1
The dechlorinated concentration repeats the above cycle over time
It will be concentrated. About 5 hours in this example
Concentration containing about 40ppm concentration of free chlorine in continuous circulation
50 liters of free chlorine water can be obtained and stored in the water storage tank 1.
I was able to.

By the way, if the same potential is continuously applied to the electrodes C and D, Ca ions in the raw water adhere to the surface of the electrodes to prevent electrolysis. To prevent this, voltages of opposite polarities are periodically applied. Reverse operation is required. Here, the polarity is exchanged every 30 minutes to remove deposits such as Ca ions and maintain the electrolysis ability. When about 40 ppm of concentrated free chlorine water is obtained by the above operation, the process for producing concentrated free chlorine water for sterilization is terminated.

Next, the discharge process will be described. The voltage applied to the electrodes C and D is stopped by a signal from the control unit 14, the circulation path 15 side of the flow path switching means 6 is closed, and the discharge path 11 side is opened, whereby the concentration of about 40 ppm stored in the water tank 1 is reached. 50 liters of the concentrated free chlorine water is discharged to the cooling tower 12, and the concentrated free chlorine water having a high concentration can be instantly contacted to sterilize and wash the Legionella spp. The cooling tower 12 of this embodiment constitutes a cooling system having a capacity of 100 refrigeration tons, and circulates about 2000 liters of cooling water. Therefore, by discharging 50 liters of concentrated free chlorine water having a concentration of about 40 ppm into the cooling water, the cooling water contains about 1 ppm concentration of free chlorine, which is a concentration suitable for sterilizing and washing Legionella spp. It becomes. It is generally said that 0.4 ppm or more of free chlorine is effective for sterilizing and washing Legionella spp. Therefore, it can be almost completely sterilized. It is desirable that the concentrated free chlorine water for sterilization is discharged from the concentrated free chlorine water generation system for sterilization at the same time as the end of the generation process, but residual free chlorine water may inevitably remain in the water storage tank 1 or the electrolytic cell 3. Many. Therefore, almost all of the concentrated free chlorine water obtained in the production process is discharged except this residual free chlorine water.

By the way, concentrated free chlorine water adheres and remains in the water storage tank 1, the pump 4, the flow path switching means 6, the electrolysis tank 3 and the circulation path 15, and oxidizes and corrodes these members. In order to prevent this, conventionally, a special anticorrosion treatment was applied to each of these members, but the system was expensive and the service life was shortened. The cleaning process of the concentrated free chlorine water generation system for sterilization of this embodiment solves such a problem. The process of producing concentrated free chlorine water for sterilization will be described below.

When the above generation process is completed, the control unit 1
The raw water electromagnetic valve 7 is opened in response to the signal from 4, and raw water, which is washing water, is stored in the water storage tank 1 at a second predetermined amount of about 50 liters. Next, the raw water is sucked by the pump 4 and poured into the electrolytic cell 3 via the flow path switching means 6, and the residual free chlorine is washed from the circulation path 15 into the water storage tank 1 and circulated. At this time, the flow path switching means 6 returns to the initial state, the circulation path 15 side is opened, and the discharge path 11 side is closed. Further, no voltage is applied to the electrodes C and D during this cleaning process. In this way, the water tank 1, the pump 4, the flow path switching means 6, the electrolysis tank 3 and the circulation path 15 are repeatedly circulated and washed to wash away the residual free chlorine inside and store the water in the water tank 1. In the concentrated free chlorine water generating system for sterilization of this embodiment, about 5 liters of concentrated free chlorine water of about 40 ppm inevitably remained as described above, and about 50 liters was newly stored as washing water. By circulating cleaning, the cleaning liquid in which the free chlorine is diluted to about 4 ppm is stored in the water storage tank 1. Here, the discharge passage 11 side of the flow passage switching means 6 is opened again, and free chlorine is about 4 p
The washing liquid diluted to pm is discharged to the cooling tower 12 to sterilize and wash Legionella spp. The concentration of free chlorine is lower than that of the concentrated free chlorine water discharged in the discharge process after the process of producing concentrated free chlorine water for sterilization, but it is sufficient to suppress the generation of Legionella spp. Further, this cleaning liquid also serves as a replenishing liquid for the cooling water in the cooling tower 12.

It is also possible to discharge almost all the washing water in the water storage tank 1 and then store the raw water again in the water storage tank 1 and repeatedly circulate and wash the inside of the concentrated free chlorine water production system for sterilization by the pump 4. About 1 hour is sufficient for these cleaning processes. In this way, the concentration of free chlorine in the wash water stored in the water storage tank 1 is diluted to about 0.4 ppm, and reaches the range of fluctuation of the content of normal tap water. At this concentration, the rate of oxidative corrosion of each member in the concentrated free chlorine water generation system for sterilization is very slow, and it is not necessary to perform a special rust preventive treatment in practice. In addition, in this concentrated free chlorine water generation system for sterilization, which often takes about a week until the start of the next concentrated free chlorine water generation process, it is common to store about 0.4 ppm of wash water. It is possible to prevent bacteria and the like from breeding. When the production process of concentrated free chlorine water is restarted after about one week, the stored wash water of about 0.4 ppm is directly used as raw water, and the chlorine concentration is detected by the concentration detection sensor connected to the control unit 14. Is detected, electrolysis is performed by adding an appropriate amount of sodium chloride aqueous solution in the chloride aqueous solution tank 2 so that the chlorine concentration becomes about 300 ppm, and new raw water is supplied to replace the wash water in the water tank 1. No need. The cooling tower 12 in this embodiment constitutes a cooling system having a capacity of 100 refrigeration tons, and washing of a concentrated free chlorine water producing system for sterilization when sterilizing and washing Legionella spp. In about 2000 liters of cooling water. I explained how. When the amount of the cooling water is other than this, it is sufficient to appropriately adjust and change the capacity and capacity of the water storage tank 1, the electrolytic tank 3 and the pump 4, and the effect of the present invention is not affected at all. .

Further, not only sterilizing and cleaning Legionella spp. Generated in the cooling tower 12, but also sterilizing and cleaning various bacteria in a device provided with a humidifier, a water / water heater, and a fountain for decoration. Also in the process, the cleaning method of the concentrated free chlorine water producing system for sterilization of the present invention is effective.

[0017]

As is apparent from the above, according to the present invention, after producing concentrated concentrated free chlorine water for sterilization, it is discharged at one time and a second predetermined amount of cleaning water is newly supplied and circulated. Therefore, special rust preventive treatment in the system is not required, maintenance is easy, and liquid treatment after cleaning can be facilitated.

[Brief description of drawings]

FIG. 1 is an explanatory view of a cleaning method for a concentrated free chlorine water generation system for sterilization in one embodiment of the present invention.

[Explanation of symbols]

 1 Water Storage Tank 2 Chloride Aqueous Solution Tank 3 Electrolysis Tank 4 Pump 5 Salt Water Pump 6 Flow Path Switching Device 7 Raw Water Solenoid Valve 8 Inlet 9 Water Level Sensor 10 Low Water Level Sensor 11 Discharge Channel 12 Cooling Tower 13 Salt Water Solenoid Valve 14 Control Section 15 Circulation Road

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C02F 1/50 531 N 540 B 550 DL L 560 F 1/76 A

Claims (1)

[Claims] 1. A water storage tank and an electrolysis tank are connected by a circulation path, and a first predetermined amount of raw water containing chloride is electrolyzed in the electrolysis cell while circulating through the circulation path and concentrated free chlorine. Concentrated free chlorine for sterilization that generates water and discharges almost the entire amount of concentrated free chlorine water of the first predetermined amount by selectively connecting the discharge path and the circulation path by the flow path switching means provided in the circulation path. A method of cleaning a water generation system, comprising: discharging the concentrated free chlorine water from the discharge passage, supplying a second predetermined amount of cleaning water to the sterilized concentrated free chlorine water generation system, and then circulating the circulation path. A cleaning method for a concentrated free chlorine water production system for sterilization, characterized in that the switching means is switched after continuing the circulation cleaning via the discharging means to discharge substantially the entire amount of the second predetermined amount of cleaning water from the discharge passage.