JPH0437757B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a back contamination prevention device such as a sterile water supply device. More specifically, the present invention relates to a reverse contamination prevention device that can disinfect the inside of a water conduit from a sterile water production device to a faucet with hypohalite generated by electrolyzing an inorganic halide aqueous solution. [Conventional technology and its problems] Sterile water that does not contain impurities such as particulates or microorganisms such as bacteria is essential for medical institutions such as hospitals, medical product manufacturers, and food manufacturers. This is well known. In recent years, filtration membranes capable of removing microorganisms such as bacteria have been developed, and sterile water production devices that can produce sterile water relatively easily and with high reliability have been put into practical use. However, the inside of the water pipe leading to the sterile water production equipment and the water outlet may be contaminated by microorganisms such as bacteria floating in the air.
Controlling contamination caused by such microorganisms has long been an issue. Conventionally, the following four methods have been mainly proposed as methods for preventing the inside of a sterile water production device and a water conduit pipe leading to a water outlet from being contaminated by microorganisms. (1) At the same time as the flow of sterile water from the sterile water production equipment stops, the heater installed in the water pipe is energized to heat the water inside the water pipe and release it as steam to the outside, thereby preventing bacteria from entering. By drying the inside of a water pipe, we prevent the growth of bacteria, and after a predetermined time has elapsed using a timer, we turn off the heater and take advantage of the fact that as the temperature inside the pipe drops, the pressure inside the pipe becomes negative. A heating sterilization method that seals the check valve installed at the water outlet using its own weight and external pressure to prevent bacteria from entering. (2) A valve that is integrally formed with a slanted circular rib on the inside of a cylindrical silicone rubber tube, which has the function of shutting off from the outside by pressing the rib from one or both directions. An elastic pinch valve method using an elastic pinch valve with (3) A method of filling faucets with silver vapor deposits, which uses the sterilizing effect of silver ions to prevent bacteria from entering through the faucets. (4) Disinfection method using disinfectants such as sodium hypochlorite water. However, in order to adopt the heat sterilization method (1) above, a complicated and large-scale device is required, which increases the cost.Also, because each part of the device is complicated, once it is contaminated with bacteria, It is extremely difficult to sterilize it. Furthermore, if used for a long period of time, the check valve may become inoperable, resulting in a decrease in functionality and, ultimately, a problem in its reliability. In the above (2) pinch valve method, the silicone rubber tube and other parts of the mechanism used do not have sterilization capabilities, so once bacteria enters the inside of the device, the inside of the device becomes contaminated with bacteria. There's a problem. If the above (3) silver deposit filling method is adopted, organic substances may adhere to the silver surface, reducing its bactericidal efficacy, and if a large amount of silver is eluted, drinking a large amount may cause allergies such as silver poisoning. May cause problems. Furthermore, since the bactericidal effect of silver ions is only on the faucet, the reliability of the bactericidal effect cannot be said to be high. In addition, if the disinfection method using a disinfectant (4) above is adopted, sodium hypochlorite is a chemically unstable compound, so it is not suitable for long-term storage and is corrosive, making it difficult to disinfect. The problem is that it takes a lot of effort to apply and is extremely difficult to handle. Therefore, the inventors of the present invention have conducted intensive research to solve the problems of the conventional technology as described above.
We have discovered a reverse contamination prevention device that can highly efficiently and reliably sterilize the inside of a water conduit from a sterile water production device to a faucet, has a simple structure, low manufacturing costs, and is easy to handle, and have developed the present invention. It was completed. [Means for Solving the Problem] That is, the present invention consists of an inorganic halide supply device, an electrolysis device, and a water stop valve provided at a water intake port, and produces water by passing raw water into a sterile water production device. After the water stop valve is closed and the sterile water is stored in the electrolytic chamber of the electrolyzer, inorganic halide is supplied from the inorganic halide supply device into the electrolytic chamber, and the inside of the electrolytic chamber and the water pipe are electrolyzed. The present invention relates to a back contamination prevention device configured to be sterilized. [Function] The back pollution prevention device of the present invention is comprised of a halide supply device, an electrolysis device, and a water stop valve provided at the water intake. If the inside of the water pipe filled with sterile water remains as it is, there is a possibility of secondary contamination due to microorganisms entering from the water intake. In the reverse contamination prevention device of the present invention, in order to prevent this secondary contamination, the water stop valve provided at the water intake is closed to store sterile water in the electrolytic chamber, and then inorganic halide is supplied into this stored water. After injecting the inorganic halide from the device, electricity is applied to the electrolytic device, and the stored water containing the aqueous halide solution is electrolyzed. When stored water is electrolyzed, the halogen ions contained in the stored water become halogen molecules through anodic oxidation.
This halogen molecule further reacts with hydroxide to produce hypohalite. When sodium chloride, for example, is used as the inorganic halide, the reaction formula for this series of reactions is as follows. NaCl + H ₂ O → NaOH + 1/2H ₂ ↑ + 1/2Cl ₂ ↑ Cl ₂ + 2NaOH → NaClO + NaCl + H ₂ O Sodium hypochlorite thus produced can be used to collect viruses, general non-spore bacteria, acid-fast bacteria, bacterial spores, filamentous fungi, algae, It is effective against most microorganisms, including protozoa, and usually has the ability to complete sterilization in a short period of time at a concentration of about 10 ppm. This sodium hypochlorite sterilizes the water stored in the electrolysis chamber and also sterilizes the inside of the water pipe. Next, by opening the water stop valve and allowing the water containing sodium hypochlorite in the electrolyzer to flow out, the interior of the water conduit from the water stop valve to the faucet can also be sterilized. [Example] An embodiment of the present invention will be described based on FIG. 1. In FIG. 1, 1 is a sterile water production device, 2 is an inorganic halide supply device, 3 is an electrolysis device, 4 is a water stop valve, and 6 is a water intake port. Raw water is supplied into the sterile water production apparatus 1 by opening the water stop valve 4, and sterile water is produced there. Examples of the sterile water production equipment 1 include commonly used distilled water production equipment, pure water production equipment, ultraviolet sterilization equipment, ultrafiltration equipment, reverse osmosis equipment, heat sterilization equipment, etc., but in addition to these, hollow fiber A module made of a polyethylene porous hollow fiber membrane having ultrafine pores with slits of 1 μm in length and 0.1 μm in width on the fiber surface, such as Stellapore (registered trademark, manufactured by Mitsubishi Rayon Co., Ltd.), can be used. The sterile water produced by the sterile water production device 1 is
By opening the water stop valve 4 provided at the water intake port, the water is sent into the electrolysis chamber of the electrolyzer 3. A valve 5 may be provided as necessary to prevent the concentration of the inorganic halide aqueous solution from changing and to limit the range of the solution to be electrolyzed. Inorganic halide is supplied to the sterile water introduced into the electrolytic chamber from the inorganic halide supply device 2 with the water stop valve 4 closed. As the inorganic halide supply device 2, for example, an inorganic halide aqueous solution supply device having a structure as shown in FIG. 2 can be used. That is, the bellows-type inorganic halide aqueous solution container 22 is stably installed by the container stabilizing rod 21.
is installed in the main body of the inorganic halide aqueous solution supply device, and by turning the inorganic halide aqueous solution supply feed handle 23, the presser plate 26 is moved by a fixed distance by the feed screw 25. By this operation, a certain amount of the inorganic halide aqueous solution in the inorganic halide aqueous solution container 22 is injected into the electrolytic chamber 31 . Further, in order to prevent the solution in the electrolytic chamber 31 from flowing back into the inorganic halide aqueous solution container 22 and changing the concentration of the inorganic halide aqueous solution in the inorganic halide aqueous solution container 22, the electrolytic chamber 31 and the inorganic halide A check valve 24 may be provided at the boundary with the aqueous solution container 22. As the inorganic halide aqueous solution container 22, plastic containers having various shapes other than the bellows shape can be used. As an example, a compressible polyethylene bottle can be used, but in this case, an air valve should be provided to ensure that the container returns to its original shape after supplying the inorganic halide aqueous solution. is preferred. Alternatively, a method may be adopted in which a fixed amount of the inorganic halide aqueous solution is injected by using a container with a syringe-like mechanism and pushing a piston a fixed length. The concentration and amount of the inorganic halide aqueous solution injected into the electrolytic device 3 vary depending on the amount of sterile water injected into the electrolysis chamber 31 in the electrolytic device 3, etc.
Although it cannot be determined unconditionally, approximately 0.1% of an inorganic halide aqueous solution with a concentration of approximately 0.1% to approximately 30% is added to approximately 10 to 40ml of sterile water in the electrolytic chamber and water conduit.
It is used by injecting ~5.0ml. In the present invention, examples of inorganic halide aqueous solutions that can be used include NaCl, KCl, LiCl, AlCl ₃ ,
Aqueous solutions of inorganic chlorides that generate chloride ions by electrolysis, such as NH ₄ Cl, CaCl ₂ , NaI,
Examples include aqueous solutions of inorganic iodides such as KI, aqueous solutions of inorganic bromides such as NaBr and KBr, and among these, NaCl is preferably used because of its ease of availability. In the present invention, in addition to the method of injecting an aqueous inorganic halide solution into the electrolytic chamber 31 as described above, for example, a predetermined amount of an inorganic halide that exhibits sustained release properties such as pellet-shaped tablets or capsules can be used. It is also possible to adopt a method of supplying the electrolyte to the electrolytic chamber 31 using. As the above-mentioned tablets, sustained-release tablets may be used in which the ingredients are coated with a hydrogel or the like so that the ingredients gradually dissolve. As the hydrogel, a crosslinked 2-hydroxyethyl methacrylate polymer or copolymer is preferably used. In addition, a sustained-release tablet is set near the electrode,
A system may be used in which the tablets are replaced periodically depending on their lifespan. The inorganic halide supplied to the electrolytic chamber 31 is mixed with sterile water in the electrolytic device 3, and then electrolyzed by applying electricity to the electrodes. For example, an apparatus having a configuration as shown in FIG. 3 can be used. In FIG. 3, two electrodes, namely an anode 32 and a cathode 33, are provided in the lower part of the electrolytic chamber 31, and the electrolysis is carried out by applying direct current from a power source 34. The electrodes used for the anode 32 and cathode 33 are usually platinum electrodes that do not undergo corrosion or other changes even when immersed in water for a long period of time, metals such as copper or nickel, or synthetic resins coated with gold or platinum. Plated or vapor-deposited electrodes are used,
In order to be able to easily replace these electrodes, the cap 35 provided with the electrodes may be fixed with screws, as shown in FIG. 3. As the power source 34, it is possible to use ordinary household AC electricity (100V) that is transformed into DC using a transformer, or a battery such as a dry cell. Further, a timer may be installed between the power source 34 and the electrodes to ensure that the power is turned on at a predetermined time. The voltage and current of the electricity applied to the anode 32 and the cathode 33 as well as the current supply time are determined in the electrolytic chamber 3.
Although it cannot be determined unconditionally because it varies depending on the type, concentration, and amount of the inorganic halide aqueous solution in the electrolytic chamber 3, for example, when NaCl is used as the inorganic halide, the electrolytic chamber 3
The effective chlorine concentration in 1 is adjusted to 0.5 to 500 ppm, and in particular to about 10 ppm or more to sterilize microorganisms such as mold. In addition, the electrolysis time using a sodium chloride aqueous solution is determined by the concentration of the sodium chloride aqueous solution,
Although it varies depending on the supply amount and current amount, it is preferably 10 to 120 minutes. In addition, when the sterile water conduit pipe 36 is provided above the electrode, the gas generated from the electrode rises to the lower end of the sterile water production apparatus 1, and the generated gas causes the hypohalite-containing water to flow. It is preferable to have such a structure because the water and sterile water are stirred. The stirring effect of such a gas becomes much greater when the electrolytic voltage is high. Therefore, if the sodium hypochlorite concentration at the upper end of the water conduit pipe is to be increased and the sterilizing ability of this portion is to be enhanced, the sodium chloride concentration in the electrolytic chamber may be lowered and/or the electrolytic current may be increased. The above-mentioned energization is usually carried out when sterile water is allowed to remain in the electrolytic chamber and the water pipe for a long time, such as at night, and does not need to be carried out during use because bacteria will not grow in the water pipe. It is usually preferable to use a solenoid valve as the water stop valve 4, but if an elastic pinch valve is used, for example, as described in JP-A No. 57-9366, it is effective to prevent microorganisms from entering from outside. This is advantageous and particularly desirable. The water stop valve 4 is
Closed when an inorganic halide aqueous solution is injected into the electrolytic chamber 31 from the inorganic halide supply device 2, when a mixed solution of the injected inorganic halide aqueous solution and sterile water is electrolyzed, and when sterile water is not used. be done. After the electrolysis is completed, if the water stop valve 4 is opened without supplying sterile water from the sterile water production device, the electrolysis chamber 31
The hypohalite-containing sterile water stored in the water pipe is discharged, which cleans the water pipe and the faucet, thereby sterilizing bacteria adhering to the water pipe.
After releasing an appropriate amount of hypohalite-containing water, the water stop valve 4 is closed. It is also possible to open the water stop valve for a short time to allow the chlorine-containing water to flow out and close the water stop valve, and to hold the chlorine-containing water for a certain period of time before opening the water stop valve 4 after the electrolysis is completed. The reverse contamination prevention device of the present invention configured as described above undergoes a sterilization process flowchart as shown in FIG. 4 or FIG.
The inside of the water conduit from the sterile water production device to the faucet is sterilized and back contamination is prevented. That is, in FIG. 4, an inorganic halide is supplied from an inorganic halide supply device to an electrolysis chamber of an electrolyzer, and then the inorganic halide aqueous solution is electrolyzed. After the electrolysis is completed, the water stop valve is opened for several seconds to several tens of seconds, and after the high concentration hypohalite-containing water flows out from the water intake port, the water stop valve is closed. Further, in FIG. 5, an inorganic halide is supplied from an inorganic halide supply device to an electrolytic chamber of an electrolytic device, and then the inorganic halide aqueous solution is electrolyzed. After electrolysis, the hypohalite-containing water obtained is held for 10 to 60 minutes, then the water stop valve is opened for several seconds to several tens of seconds, and the highly concentrated hypohalite-containing water is released from the water intake. After draining, the water stop valve is closed. In addition, if the reverse pollution prevention device is not used for a long time, such as at night, store water containing chlorine as shown in Figure 6, and open the water stop valve a little before use to release high concentration water. Preferably, the water stop valve is closed after the hypohalite-containing water has flowed out from the water intake. Next, the present invention will be explained in more detail based on experimental examples and examples, but the present invention is not limited only to these experimental examples and examples. Examples 1 to 6 Open the water stop valve, inject tap water into the sterile water production device to produce sterile water, and send it to the electrolytic chamber with a capacity of 30 ml, then close the solenoid valve and fill the electrolytic chamber with sterile water. was stored. Next, a sodium chloride aqueous solution was injected into the electrolytic chamber under the conditions shown in Table 1, electricity was applied to the two electrodes, and the chlorine concentration in the electrolytic chamber was measured after 60 minutes had elapsed. The results are also listed in Table 1.

[Table] Example 1 Inoculate 0.5 ml of the inoculum solution cultured by the method detailed below into 30 ml of sterile water in the pipe,
The number of bacteria inoculated into the electrolytic chamber is 10 ⁵ using a syringe (for 1 ml).
The cells were inoculated at ~10 ⁶ cells/ml. Then the concentration
0.5 ml of a 10% aqueous sodium chloride solution was injected into the electrolytic chamber using an inorganic halide supply device, and a direct current of 10 mA was applied to the two electrodes to perform electrolysis for 60 minutes. After electrolysis, after draining the sodium hypochlorite-containing water, sterile water was passed through a sterile water production device (Stelapore, manufactured by Mitsubishi Rayon Co., Ltd.), and water was sampled from the faucet. ``General test method''
Sterility test was conducted based on 37. Sterility Test Method.
Judgments were made by culturing at 30°C for 7 days for bacterial tests and 10 days at 20°C for fungal tests. The results are shown in Table 2. The inoculum was prepared using the following method. (Adjustment of inoculum) E. coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida, Albicans, Aspergillus, etc.
E. coli, Staphylococcus aureus, and Pseudomonas aeruginosa were cultured at 35°C for 24 hours, and then passaged for 3 consecutive days. Candida and albicans were cultured at 25°C for 48 hours, and then passaged for 2nd generation every 2 days. generation, aspergillus
niger was cultured at 25°C for 1 week. As for Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans, they were washed three times with a centrifuge at 3000 rpm for 10 minutes using sterile physiological saline, and a bacterial solution containing 10 ⁸ bacteria/ml was obtained. Regarding Aspergillus niger,
Prepare a spore suspension using sterile physiological saline containing 0.05% polysorbate 80, and use a centrifuge to create a spore suspension.
After washing three times at 3000 rpm for 10 minutes, the cells were resuspended using sterile physiological saline to obtain a bacterial solution containing 10 ⁷ cells/ml.

[Table] * When no electricity is applied As can be seen from the above results, secondary contamination between the outlet side of the sterile water production equipment and the faucet is completely prevented by the reverse contamination prevention device of the present invention, and no water is removed from the faucet. This means that you can always get sterile water. [Effects of the Invention] As described above, according to the back contamination prevention device of the present invention, the inside of the water conduit from the sterile water production device to the faucet can be reliably sterilized and back contamination can be prevented, and the structure is simple. It is also extremely easy to handle.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the back contamination prevention device of the present invention, FIG. 2 is a schematic explanatory diagram of the inorganic halide supply device,
FIG. 3 is a schematic illustration of the electrolyzer, and FIGS. 4, 5, and 6 are flowcharts of the sterilization process. Main symbols in the drawing: 2... Inorganic halide supply device, 3... Electrolysis device, 4... Water stop valve.

Claims (1)

[Claims] 1. Consisting of an inorganic halide supply device, an electrolytic device, and a water stop valve installed at a water intake port, the sterile water produced by passing raw water through the sterile water production device is water-stopped. After the valve is closed and water is stored in the electrolytic chamber of the electrolytic device, an inorganic halide is supplied from an inorganic halide supply device into the electrolytic chamber and electrolyzed, thereby sterilizing the electrolytic chamber and the water pipe. Back pollution prevention device. 2. The back pollution prevention device according to claim 1, wherein the water stop valve is an elastic pinch valve. 3. The back pollution prevention device according to claim 1, wherein the water stop valve is configured to be opened for a certain period of time after electrolysis is completed. 4. The back contamination prevention device according to claim 1, wherein the inorganic halide supply device is configured to supply a fixed amount of inorganic halide. 5. The back contamination prevention device according to claim 1, wherein the inorganic halide is sodium chloride. 6. The reverse contamination prevention device according to claim 1, wherein the inorganic halide exhibits sustained release properties in water. 7. The back contamination prevention device according to claim 1, wherein the inorganic halide is an aqueous solution.