JPS6320193B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field to which the invention pertains] The present invention provides a sterile system for supplying high-purity water in fields such as the pharmaceutical industry and food industry, which use a large amount of so-called high-purity water such as highly purified water or distilled water. This invention relates to a sterilization method that maintains the condition. [Prior art and its problems] Due to the nature of the products, the water used in the pharmaceutical and food industries is required to be highly purified, and at the same time, its supply system must be maintained in a sterile state at all times. For example, in the food industry, it is used for preparing water, cleaning containers, cleaning mixing containers, and cleaning various filters. In the pharmaceutical industry, water is used for various purposes such as mixing water, washing mixing containers, and cleaning filling containers, so naturally the supply systems are diverse, and recently, intensive treatment has been promoted from the perspective of rational water management. , and are becoming increasingly larger and more complex. In water supply systems that are becoming more complex and larger, there are many tanks, valves, filters, pumps, and other equipment or packing parts, which makes it difficult for bacteria to enter from air contact parts or packing parts. There is a risk of contamination and the growth of bacteria during retention in the tank, so maintaining the high purity water supply system in a sterile state requires very sophisticated management and expense. Therefore, high-purity supply systems are often sterilized once every 1 to 7 days, depending on the purpose of use or the system components. Sterilization methods include heat treatment, ultraviolet irradiation,
Various treatment methods such as chemical injection method or ozone injection method are used. Of these, the ozone injection method is viewed as a problem in the pharmaceutical industry, where (1) it has strong chemical and heat resistance (destructed in 30 minutes or more at 250°C or 120 minutes or more at 180°C) and is difficult to process; The pyrogens (bacterial endotoxins) that are used can also be treated in a short time. (2) No wastewater is generated during sterilization. (3) It is simple to operate and easy to automate. (4) Economically superior. Because it has many excellent features such as, it is widely used in various fields. The attached FIG. 1 is a diagram showing the configuration of a conventional system to which the ozone injection method is applied. In FIG. 1, high-purity water produced in a high-purity water production process 1 is supplied via a storage tank 4 and a water supply device 8. When performing sterilization treatment in this system, after closing the valve 20 to form a closed channel system, the circulation pump 12 is driven to circulate high-purity water in the system in the direction of arrow A, and the ozone generator 2 generates high-purity water. Ozone is dissolved into high purity water via an ozone injector 3. The ozone-containing high purity water produced in this way is
Sterilization within the system is carried out by circulating the closed water system. After a certain period of time has elapsed and the completion of sterilization is confirmed, the ozone generator 2 is stopped, and the ultraviolet lamp 5 is turned on to irradiate the circulating water in the system with ultraviolet rays, thereby decomposing the ozone dissolved in the high purity water. After the completion of ozone decomposition is confirmed by the ozone monitor 6, supply of high-purity water becomes possible. However, in this ozone injection sterilization method, ozone remaining in high-purity water is decomposed by ultraviolet irradiation, but ultraviolet irradiation (1) requires a long time to decompose ozone. The attached Figure 2 shows the state of decomposition of ozone dissolved in water by ultraviolet irradiation, with the vertical axis representing the dissolved ozone concentration and the horizontal axis representing the ultraviolet irradiation time, and examining the relationship between the two. According to the results, about 2
It takes about one hour to reduce the dissolved ozone level to below 0.1 ppm, and about three hours to decompose it to a level where it cannot be chemically detected. The long time it takes for ozone to decompose due to ultraviolet irradiation makes it impossible to apply high-purity water supply systems using ozone injection methods, or sterilization systems and continuous systems. This is a difficult point in doing so. (2) Ultraviolet lamps have a relatively short lifespan and require a lot of maintenance work. The lifespan of an ultraviolet lamp is 2000 to 7000 when continuously lit.
It is said that the lifespan will be even shorter as the number of flashes increases. Therefore, in the case of a sterilization method in which ultraviolet irradiation is applied to decompose ozone, the light flashes on and off each time the sterilization process is performed, and it is therefore difficult to expect a long service life, which tends to cause maintenance and economic problems. These are some of the difficulties in designing a high-purity water supply system using ozone. [Object of the Invention] The present invention has been made in view of the above-mentioned problems, and aims to provide an economically superior sterilization method that solves the drawbacks of the process of decomposing dissolved ozone by ultraviolet irradiation. purpose. [Summary of the Invention] The present invention provides a high-purity water supply system configured to supply high-purity water from a high-purity water production process through a water supply device such as a filler or a washer.
Ozone is injected into the high-purity water supplied from the high-purity water production process to sterilize the high-purity water supply system, or pyrogen is decomposed and ozone dissolved in the high-purity water after sterilization is removed. The purpose is to achieve the above object by passing through an activated carbon layer immersed in water. [Examples of the Invention] The present invention will be described based on Examples. Third
The figure is a system configuration diagram showing the concept of a sterilization method for a high-purity water supply system to which the present invention is applied. Third
In the figure, the same parts as in FIG. 1 are given the same reference numerals. Reference numeral 1 indicates a high-purity water production process, and after this high-purity water production process 1, an ozone injector 3, such as a line mixer, is configured to receive ozone-containing air from an ozone generator 2. and,
A storage tank 4 for ozone-containing high purity water (hereinafter referred to as ozone-containing water) supplied via an ozone injector 3, an ozone monitor 6 for detecting the ozone concentration of the ozone-containing water, and the storage tank 4 and the ozone An activated carbon tank 30 and a filter 31 that branch off from the middle of the path between the monitor 6 and the ozone-containing water pass therethrough, a water supply device 8 consisting of a filler or a washer, and a circulation pump 1
2 are successively connected by pipes to form a waterway system, and the water sent out from this circulation pump 12 is placed in the middle of the piping for supplying high purity water from the high purity manufacturing device 1 to the ozone injector 2. Confluence (confluence point 2
1) One closed channel is constructed as follows. Then, downstream of the storage tank 4, it is branched and one side is connected to the ozone monitor 6 through a valve 16. On the other hand, a valve 15 is connected to an intervening activated carbon tank 30 slightly downstream of the branch point, and the end is connected to a pipe upstream of the ozone monitor 6 via a filter 31 and a valve 17. Also, in this closed channel system, valves 1 are installed between the water supply device 8 and the circulation pump 12, between the circulation pump 12 and the confluence 21, and between the high purity water production process 1 and the confluence 21.
8, 19, and 20 are interposed. Note that the storage tank 4 has a discharge pipe 12 equipped with a discharge ozonator 10 for releasing undissolved parts of the injected ozone-containing air and rendering surplus ozone harmless.
and an air supply pipe 13 interposed with a sterilization filter 11 to prevent the space inside the storage tank 4 from becoming negative pressure.
is provided. Further, the ozone generator 2 is configured to be controlled based on the measured value of the ozone monitor 6 (not shown). The sterilization method for the high-purity water supply system configured as described above operates as follows. valve 20,
15 and 17 are closed, valves 18 and 19 are opened, and the ozone generator 2 and circulation pump 12 are operated to circulate high-purity water in the closed channel system, and the ozone injector 3 is used to inject ozone-containing air into the circulating water. The system is filled with ozone-containing water by dissolving ozone and filling the closed channel system with ozone-containing water. The ozone-containing water is then circulated through a closed channel for a certain period of time to sterilize each part of the system. During the sterilization process, the ozone monitor 6 controls the ozone concentration in the water so that it is always maintained at the concentration necessary for sterilization. After a predetermined period of time has elapsed and the completion of sterilization is confirmed, the ozone generator 2 is stopped, and the valve 16 is then throttled.
Valves 15 and 17 are opened to allow ozone-containing water in the system to pass through activated carbon tank 30 and filter 31. After circulating high-purity water in the system, the degree of decomposition of dissolved ozone is detected by the ozone monitor 6 and safety is confirmed, and then the valve 1
8, 19 and 15, 17 are closed, valves 16 and 20 are opened, and the supply of high-purity water is started. It is well known that ozone is decomposed by activated carbon, and if the reaction temperature is high, carbon dioxide gas is produced at the same time as the activated carbon is consumed, and if the reaction temperature is low, only oxygen is produced due to catalytic decomposition, and the activated carbon is consumed. It is also a well-known fact that there is no such thing. However, all of these facts are reactions in the gas phase, and it is not clear whether ozone is similarly decomposed in water. The inventor of the present invention obtained the idea of the present invention by conducting an experiment to determine whether activated carbon immersed in water is effective in decomposing dissolved ozone using an apparatus as shown in FIG. 4. That is, ozone injector 3 is installed in one closed channel.
(configured so that ozone-containing air can be supplied from the ozone generator 2), an activated carbon tank 30, and a circulation pump 12 are interposed, and the upstream side of the activated carbon tank 30,
Using an experimental device configured with a sampling point for measuring dissolved ozone concentration on the downstream side, experiments were conducted on various types of dissolved ozone-containing water, and the results shown in the following table were obtained.

〔Effect of the invention〕

As explained above, the present invention is a method for sterilizing a high-purity water supply system, in which dissolved ozone injected into high-purity water is decomposed by passing through an activated carbon layer immersed in the water. (1) Because ozone decomposition time is short,
Sterilization time can be significantly shortened. (2) Because the process is carried out at low temperatures, there is less consumption of activated carbon, and maintenance is easy. (3) There is no particular need for electricity, water, etc. for ozone decomposition. There are other effects. Therefore, as a sterilization method for a high-purity water supply system, it is expected to save resources and achieve low operating costs, making it possible to design an extremely economical system.

[Brief explanation of the drawing]

Figure 1 is a system configuration diagram of a conventional high-purity water supply system using the ozone injection method, Figure 2 is a graph showing the correlation between dissolved ozone concentration and ultraviolet irradiation time, and Figure 3 is a diagram showing the correlation between dissolved ozone concentration and ultraviolet irradiation time. FIG. 4 is a system configuration diagram of a high-purity water supply system, FIG. 4 is a system configuration diagram of an experimental device, and FIG. 5 is a system configuration diagram of another application example of the present invention. 1: High purity water production process, 3: Ozone injector,
4: Storage tank, 5: Ultraviolet irradiator, 6: Ozone monitor, 8: Water supply device, 12: Circulation pump, 15,1
6, 17, 18, 19, 20: valve, 30: activated carbon tank, 31: filter, 32, 33: ozone monitor.

Claims (1)

[Claims] 1 Filler with high-purity water from the high-purity water production process,
In a high-purity water supply system configured to be supplied via a water supply device such as a washer, ozone is injected into the high-purity water supplied from the high-purity water production process to cause the inside of the high-purity water supply system to flow. A method for sterilizing a high-purity water supply system, characterized in that ozone dissolved in the high-purity water after sterilization is decomposed by passing through an activated carbon layer immersed in the water.