JP2007159820A - Ozone sterilization method and its apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ozone sterilization method capable of setting appropriate processing time even when an ozone concentration changes, and its apparatus. <P>SOLUTION: When supplying ozone from an ozone generator 11 into a sterilization chamber 10 and sterilizing a sterilization object, the ozone concentration C inside the sterilization chamber 10 is detected, the ozone concentration C is integrated at every interval of time T, and sterilization is stopped when the integration value (CT) reaches a fixed value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ozone sterilization method and an apparatus thereof capable of setting a necessary sterilization treatment time for an object to be sterilized in a sterilization chamber.

  Conventionally, in ozone sterilization, ozone concentration and sterilization treatment time necessary for sterilizing an object to be sterilized are set by a basic test or the like, and the ozone generator is controlled so that the set ozone concentration is obtained.

  FIG. 5 shows the change in ozone concentration with respect to the temperature change in the ozone generator. The ozone gas concentration was 447 ppm when the ambient temperature was 20 ° C., but it dropped to 340 ppm at 30 ° C. and 259 ppm at 40 ° C.

  Therefore, in order to stabilize the output of the ozone generator within a certain range, the ozone generator is cooled and kept at a constant temperature, and the ozone concentration generated by the ozone generator is adjusted so that the set ozone concentration is obtained. Feedback control is performed.

JP 2002-96081 A JP 11-347106 A

  However, constant control of the temperature of the ozone generator increases the cost of the apparatus, and daily management of the ozone generator at the site of use is also required. Furthermore, when the ozone concentration cannot be controlled to a certain level, there is a method of setting the ozone generator in advance so that the concentration is lower than the lower limit necessary for sterilization. There is a problem of damaging the material.

  Then, the objective of this invention is providing the ozone sterilization method and its apparatus which can set the suitable process time even if the said subject is solved and ozone concentration changes.

  In order to achieve the above object, according to the first aspect of the present invention, when ozone is supplied into the sterilization chamber and the object to be sterilized is sterilized, the ozone treatment is controlled so that the product of ozone concentration and time becomes constant. This is an ozone sterilization method.

  In the invention of claim 2, when ozone is supplied into the sterilization chamber and the sterilization target is sterilized, the ozone concentration in the sterilization chamber is detected, and the ozone concentration is integrated for each time. The ozone sterilization method is characterized in that the sterilization process is stopped when the temperature reaches a certain level.

  According to a third aspect of the present invention, the product of ozone concentration and time is detected by monitoring the amount of discoloration of the chemical substance that changes its color by reacting with ozone or the intensity of the discoloration by an optical or electrical method. 1. The ozone sterilization method according to 1.

  Invention of Claim 4 supplies ozone water in a sterilization tank, and when sterilizing the sterilization object in a sterilization tank, the product of ozone water concentration and time, or ozone water concentration is integrated for every time, The ozone sterilization method is characterized in that sterilization is stopped when the integrated value reaches a constant value.

  The invention according to claim 5 is an ozone sterilizer for supplying ozone into a sterilization chamber and sterilizing an object to be sterilized, an ozone generator for supplying ozone into the sterilization chamber, an ozone concentration and time in the sterilization chamber An ozone CT value detector for detecting an integrated value, and a control circuit for stopping the sterilization process when the integrated value from the ozone CT value detector is input and a detected value corresponding to a predetermined CT value is obtained. This is an ozone sterilization apparatus.

  According to a sixth aspect of the present invention, in an ozone sterilization apparatus that supplies ozone into a sterilization chamber and sterilizes an object to be sterilized, an ozone generator that supplies ozone into the sterilization chamber and an ozone concentration in the sterilization chamber are monitored. An ozone concentration measuring device and a control circuit that calculates a product of ozone concentration and time output from the ozone concentration measuring device and stops the sterilization process when the product reaches a constant value. It is an ozone sterilizer.

  In the invention of claim 7, the control circuit comprises an arithmetic circuit and a timer circuit, and the arithmetic circuit integrates the electrical signal of the ozone concentration output from the ozone concentration measuring device with the time output from the timer circuit, The ozone sterilizer according to claim 6, wherein the sterilization process is stopped when the integrated value becomes a constant value.

  The humidity control function is connected to the sterilization chamber, and the control circuit controls the humidity control function so as to keep the relative humidity in the sterilization chamber at 60 to 98 RH. It is an ozone sterilizer according to the above.

  According to a ninth aspect of the present invention, a temperature control function is connected to the sterilization chamber, and the control circuit controls the temperature control function so as to keep the temperature in the sterilization chamber at room temperature to 55 ° C. Is an ozone sterilizer.

  According to a tenth aspect of the present invention, in the sterilization chamber, an ozonolysis device for decomposing ozone gas in the exhaust gas when ozone is replaced with air by aeration after sterilization is connected. It is an ozone gas sterilizer of description.

  The invention of claim 11 is an apparatus for supplying ozone water into a sterilization tank and sterilizing an object to be sterilized in the sterilization tank, and detecting a product of ozone water concentration and time in the sterilization tank. And a control circuit for stopping the sterilization when the detected value of the liquid-phase ozone CT value detector is inputted and the CT value becomes a predetermined value.

  The invention of claim 12 is an apparatus for supplying ozone water into a sterilization tank and sterilizing an object to be sterilized in the sterilization tank, an ozone water concentration detector for detecting the ozone water concentration in the sterilization tank, and ozone water An ozone sterilization apparatus comprising: a control circuit that integrates ozone water concentration from a concentration detector every time and stops sterilization when the integrated value reaches a constant value.

  According to the present invention, by controlling the ozone sterilization treatment so that the product of the ozone concentration and the time becomes constant, the excellent effect that the same sterilizing effect can be always obtained is exhibited.

  A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 denotes a sterilization chamber in which an object to be sterilized is accommodated, and an ozone generator 11 is connected to the sterilization chamber 10. The ozone generator 11 includes an oxygen production device and an ozonizer that introduces oxygen produced by the oxygen production device into ozonizer, and can supply ozone (ozone gas) of several thousand ppm to several tens of thousands ppm to the sterilization chamber 10. It has become.

  The ozone supplied into the sterilization chamber 10 is sucked and exhausted by the vacuum pump 12, and ozone is decomposed and exhausted by the ozone decomposer 13.

  The sterilization chamber 10 is connected with a humidity control function 15 such as a humidifier for adjusting the humidity in the chamber, and a temperature control function 14 such as a heater for maintaining the interior of the sterilization chamber 10 at room temperature to 55 ° C. The

  In performing the ozone sterilization of an object to be sterilized in the sterilization chamber 10, the temperature inside the sterilization chamber 10 is preheated by the temperature control function 14 as preconditioning.

  Thereafter, the inside of the sterilization chamber 10 is sucked with the vacuum pump 12, and the humidity control function 15 is used to maintain the relative humidity within the range of 60 to 98RH so that the temperature control function 14 maintains the normal temperature to 55 ° C. At the same time, ozone is supplied from the ozone generator 11 to a predetermined concentration or more and sterilized until a predetermined CT value is reached. After sterilization, air is supplied from the compressor of the ozone generator 11 or a separate air supply line ( Air is supplied from the inside of the sterilization chamber 10 and is aspirated and exhausted by the vacuum pump 12 to aerate the inside of the sterilization chamber 10, and all the ozone in the sterilization chamber 10 is replaced with air. To do.

  In the present invention, the sterilization chamber 10 is provided with an ozone concentration measuring device 16, and the detected value of the ozone concentration measuring device 16 is input to the control circuit 17 as an electrical signal. The time product (CT value) is controlled to be constant.

  The control circuit 17 includes an arithmetic circuit 18 and a timer circuit 19, and the arithmetic circuit 18 outputs an electrical signal of ozone concentration (C) output from the ozone concentration measuring device 16 to a time (T) output from the timer circuit 19. Is integrated to calculate an integral value (CT), and when the value reaches a predetermined value for each sterilization target, the sterilization process is stopped and the aeration described above is performed.

  Normally, the sterilizing effect by ozone is the same as the product of ozone concentration and time (T) even if the ozone concentration (C) changes. In other words, the sterilization effect of the sterilization target is dependent on the CT value, and even if the ozone concentration changes, the same sterilization effect can be obtained if the CT value is made constant.

  The bactericidal effect is different from the resistance by ozone depending on the target fungus. Therefore, the bactericidal performance is determined by experimentation from the bactericidal properties of each fungus in the CT value, If the CT value is set with the bacterial species having the highest CT value, the optimum sterilization control can be performed.

  In this case, if the temperature and humidity environment in the sterilization chamber 10 is made constant by the temperature control function 14 and the humidity control function 15, the control by the CT value can be made more reliable. That is, when the humidity is high, ozone becomes OH radicals, and the sterilization function is further improved. When the humidity is low, the function is lowered. Therefore, the humidity control function 15 uses the sterilization chamber so that the relative humidity at the CT value obtained by the experimental value is obtained. Since the relative humidity within 10 is controlled and the bactericidal effect is temperature-dependent, the temperature control function 14 controls the temperature so that the temperature condition is the CT value obtained by the experimental value, thereby further increasing the CT. Sterilization control based on the value can be performed.

  As described above, the ozone concentration from the ozone generator 11 does not need to be constant, and the water cooling function and the ozone concentration feedback control function for stabilizing the ozone concentration become unnecessary, and the cost of the ozone generator 11 can be reduced.

  Moreover, since it can control to the minimum ozone contact required for sterilization, the damage given to the sterilization target object can be minimized, the sterilization treatment can be surely performed, and the treatment without excess or deficiency can be performed.

  Regarding the sterilization characteristics of the CT value, the sterilization level increases as the CT value increases. For example, the sterilization level can be arbitrarily set by setting the CT value high when the number of primary bacteria to be processed is large and setting it low when the number is low. Further, when setting the same sterilization level, the sterilization process can be performed in a short time by increasing the ozone concentration while keeping the CT value constant.

  The ease and difficulty of sterilization with ozone differ depending on the microorganism, and the CT value characteristic of sterilization is unique to each microorganism. Since the target bacteria can be identified in pharmaceutical product factories and medical device manufacturing factories that frequently manage microorganisms subject to sterilization, the minimum necessary sterilization conditions can be set from the CT value characteristics of the specific bacteria, resulting in damage to materials. Can be reduced more.

  On the other hand, when it is difficult to identify bacteria such as hospitals, the sterilization level can be ensured by setting the sterilization conditions with the CT value characteristics of microorganisms (heat-resistant Bacillus subtilis spores) that are most difficult to sterilize with ozone. .

  In the above-described embodiment, the ozone concentration in the sterilization chamber 10 is detected by the ozone concentration measuring device 16, and the control circuit 17 integrates the ozone concentration detected by the ozone concentration measuring device 16 with time to obtain the CT value. As explained in the example, the control circuit 17 detects the physical quantity corresponding to the product of the ozone concentration and time, for example, the degree of discoloration using a chemical substance that changes color by reacting with ozone by an optical or electrical method. And may be configured to be controlled.

  Moreover, although demonstrated in the example which sterilizes the object to be sterilized by ozone, deodorization and oxidation treatment by ozone gas treatment are also included in the ozone sterilization of the present invention.

  FIG. 2 shows another embodiment of the present invention.

  In the embodiment of FIG. 1, the example in which the ozone gas concentration in the sterilization chamber 10 is detected and this is integrated every time to obtain the CT value has been described, but in this embodiment, the ozone CT is added to the sterilization chamber 10. The value detector 16a is provided, the ozone CT value detector 16a detects the CT value per unit time, and outputs this to the control circuit 17, whereby the control circuit 17 has reached the predetermined value. Sometimes sterilization is stopped.

  In the form of FIG. 1, the ozone concentration is integrated every unit time to obtain the CT value, whereas in this form, the CT value detector 16a is connected to the control circuit 17 when a constant CT value is obtained. Since the output is performed, the circuit configuration can be simplified.

  FIG. 3 shows a modification of the embodiment of FIG. 1, wherein ozone from the ozone generator 12 is humidified by the humidifier 20 and supplied to the sterilization chamber 10. The humidifier 20 humidifies ozone by bringing ozone from the ozone generator 12 into contact with water (ozone water) in the humidifier 20, and the water is set to the same temperature as that of the sterilization chamber 10. Therefore, the temperature adjustment after introducing humidified ozone can be shortened.

  In this embodiment, after the sterilization chamber 10 is evacuated and then humidified ozone gas is supplied by the humidifier 20, the time required for the humidity in the sterilization chamber 10 to reach a predetermined humidity can be shortened.

  FIG. 4 shows still another embodiment of the present invention.

  Moreover, in the above-mentioned embodiment, although the example which supplies ozone gas to the sterilization chamber 10 was demonstrated, in this example, ozone water is supplied from the ozone water manufacturing apparatus 31 to the sterilization tank 30, and the sterilization target object in the sterilization tank 30 is shown. The ozone water in the sterilization tank 30 is drained by the water pump 32, and the ozone accumulated in the sterilization tank 30 is exhausted by the blower 34 via the exhaust ozone gas decomposer 33.

  Also in this embodiment, when the ozone water concentration measuring device 36 measures the ozone concentration, the ozone water concentration is integrated by the arithmetic circuit 38 and the timer circuit 39 of the control circuit 37, and the integrated value (CT) becomes a predetermined value. Try to stop sterilization.

  At this time, the control circuit 37 controls the blower 34, the ozone water production apparatus 31, and the water pump 32 to control the ozone water supply amount, the drainage amount, and the exhaust ozone gas amount.

  Further, instead of the ozone water concentration detector 16, a liquid phase ozone CT value detector may directly detect the CT value, and the control circuit 37 may stop sterilization when the CT value reaches a predetermined value.

  In this embodiment, sterilization is performed with ozone water, but the sterilization state can be accurately detected by the CT value as in the case of sterilization with ozone gas.

  In the present embodiment, the example in which the sterilization target is sterilized with ozone water has been described. However, as a sterilization target, it is needless to say that the present invention can also be applied to decomposition of organic matter and microbial decomposition in waste water.

It is a figure which shows one embodiment of this invention. It is a figure which shows other embodiment of this invention. It is a figure which shows the modification of FIG. It is a figure which shows other embodiment of this invention. It is a figure which shows the ozone concentration change with respect to a temperature change in an ozone generator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sterilization chamber 11 Ozone generator 12 Vacuum pump 13 Ozone decomposer 16 Ozone concentration measuring device 17 Control circuit

Claims (12)

  An ozone sterilization method comprising controlling ozone treatment so that a product of ozone concentration and time is constant when supplying ozone into a sterilization chamber and sterilizing an object to be sterilized.   When ozone is supplied into the sterilization chamber and the object to be sterilized is sterilized, the ozone concentration in the sterilization chamber is detected and the ozone concentration is integrated over time, and the integrated value reaches a constant value. The ozone sterilization method characterized by stopping a sterilization process.   The ozone sterilization method according to claim 1, wherein the product of the ozone concentration and the time is detected by monitoring the amount of color change or the density of the color change of a chemical substance that reacts with ozone by an optical or electrical method.   When ozone water is supplied into the sterilization tank and the object to be sterilized in the sterilization tank is sterilized, the product of ozone water concentration and time, or ozone water concentration is integrated for each hour, and the integrated value reaches a constant value. The ozone sterilization method characterized by stopping sterilization when it is carried out.   In an ozone sterilization apparatus that supplies ozone into a sterilization chamber and sterilizes an object to be sterilized, an ozone generator that supplies ozone into the sterilization chamber, and an ozone CT that detects an integrated value of ozone concentration and time in the sterilization chamber An ozone sterilization comprising: a value detector; and a control circuit for stopping an sterilization process when an integrated value from the ozone CT value detector is input and a detection value corresponding to a predetermined CT value is obtained. apparatus.   In an ozone sterilization apparatus that supplies ozone into a sterilization chamber and sterilizes an object to be sterilized, an ozone generator that supplies ozone into the sterilization chamber, an ozone concentration measuring device that monitors the ozone concentration in the sterilization chamber, and ozone An ozone sterilization apparatus comprising: a control circuit that calculates a product of ozone concentration output from a concentration measuring device and time and stops the sterilization process when the product reaches a constant value.   The control circuit is composed of an arithmetic circuit and a timer circuit. The arithmetic circuit integrates the electrical signal of the ozone concentration output from the ozone concentration measuring device with the time output from the timer circuit, and the integrated value becomes a constant value. The ozone sterilization apparatus according to claim 6, wherein the sterilization process is stopped when it becomes.   The ozone sterilizer according to any one of claims 5 to 7, wherein a humidity control function is connected to the sterilization chamber, and the control circuit controls the humidity control function so that the relative humidity in the sterilization chamber is maintained at 60 to 98 RH. .   The ozone sterilizer according to any one of claims 5 to 8, wherein a temperature control function is connected to the sterilization chamber, and the control circuit controls the temperature control function so as to keep the temperature in the sterilization chamber at a normal temperature to 55 ° C.   The ozone gas sterilizer according to any one of claims 6 to 9, wherein the sterilization chamber is connected with an ozone decomposer that decomposes ozone gas in the exhaust gas when ozone is replaced with air by aeration after sterilization.   In a device for supplying ozone water into a sterilization tank and sterilizing an object to be sterilized in a sterilization tank, a liquid phase ozone detector for detecting the product of ozone water concentration and time in the sterilization tank, and its liquid phase ozone CT An ozone sterilization apparatus comprising: a control circuit that stops sterilization when a detection value of a value detector is input and a CT value reaches a predetermined value.   In an apparatus that supplies ozone water into the sterilization tank and sterilizes the sterilization target in the sterilization tank, an ozone water concentration detector that detects the concentration of ozone water in the sterilization tank, and ozone water from the ozone water concentration detector An ozone sterilizer comprising: a control circuit that integrates the concentration every time and stops sterilization when the integrated value reaches a constant value.

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