JP5958492B2 - Gas nitrogen oxide generation method and generator - Google Patents

Description

  The present invention relates to a generation method and an apparatus for generating gaseous nitrogen oxides from liquid nitrogen oxides.

In the field of pharmaceutical manufacturing, research, manufacturing, and testing of pharmaceuticals are conducted using clean rooms, clean booths, and sterilization chambers that are kept almost sterile while preventing contamination by bacteria, microorganisms, and dust. . In the clean room, airborne particle concentration is controlled, the flow of fine particles into the chamber, suppress the generation and stagnation minimized, 20 to 300 m ³ approximately the size of a room where the temperature, humidity and pressure are controlled if necessary Is formed. The clean booth forms a simple clean room of about 2 to ³⁰ m ³ developed for the purpose of cleaning the local work environment. The isolator is a large container of about 2 to 20 m ³ that can block the air inside the apparatus from the outside air and can be manually operated from outside by rubber gloves provided on the transparent front member.

  The air in the clean room is sucked or circulated by blowing air, and the suspended fine particles are removed by the filter, and the clean room is maintained in a substantially sterilized state. In this way, basically, if suspended particulates are eliminated, microorganisms and bacteria can be eliminated, and microbial contamination in the clean room can be prevented. However, in practice, the removal of particulates with a filter alone cannot sufficiently remove bacteria contained in the air stagnating in the corners of the clean room, and contamination such as microorganisms adhering to the walls and floors. The material cannot be removed with a filter by aspiration or ventilation. For this reason, it is necessary to periodically sterilize the clean room.

As a sterilization technique for an object to be sterilized such as a clean room, a gas sterilization method using formaldehyde, hydrogen peroxide (H ₂ O ₂ ) or ozone (O ₃ ) as a sterilization gas is known. In gas sterilization, a sterilization gas is supplied from a gas production device or gas cylinder to the sterilization chamber, filled, and held for a certain period of time, thereby killing microorganisms and bacteria floating in the air in the sterilization chamber or adhering to walls. Can be made.

  On the other hand, gas sterilization is also used when reusing a used medical device contaminated with microorganisms. In sterilization of medical equipment, an autoclave (high-pressure steam sterilizer) is generally used. However, autoclave sterilization that heats up to about 130 ° C cannot be used for heat-sensitive materials such as rubber. Even in sterilization, pressurized water vapor of about 2 atm enters the resin gap, and repeated sterilization operations promote the deterioration of the resin. For this reason, gas sterilization is particularly effective for sterilizing medical devices that are vulnerable to high temperatures and pressure.

  In gas sterilization of medical equipment, ethylene oxide gas (EOG) is often used. Ethylene oxide is a colorless and transparent substance having an ether odor and becomes a gas around 20 ° C. The ethylene oxide gas for sterilization is diluted with carbon dioxide, and filled in a high pressure container with a mixed gas of about 20% ethylene oxide and about 80% carbon dioxide. A mixed gas containing ethylene oxide is supplied from a high-pressure container to a sterilization space of a sterilization chamber in which a clean room or a medical device is arranged, and the ethylene oxide gas concentration in the sterilization space is maintained for a certain time, so that the medical device is sterilized.

  As a method for sterilizing a space to be sterilized, a system for sterilizing an isolator with hydrogen peroxide disclosed in Patent Document 1 is known. The system of Patent Document 1 includes a sterilization gas supply unit, a gas passage connecting the sterilization gas supply unit and the isolator, and the sterilization gas supply unit includes an evaporator for evaporating liquid hydrogen peroxide, and an evaporator. It has an injector for dripping liquid hydrogen peroxide and a heater for heating the air blown to the evaporator, and the inside of the isolator is sterilized by the vaporized hydrogen peroxide.

  Patent Document 2 discloses an apparatus for sterilizing an object to be sterilized (medical equipment, chemical container, etc.) in a sterilization area with an ozone sterilization apparatus. That is, ozone gas is exposed to an object to be sterilized for a certain period of time, air is introduced from an aeration line, and the ozone inside the sterilization area is ventilated.

Furthermore, nitrogen oxides are attracting attention as sterilizing agents. Nitrogen oxides include nitric oxide (NO), nitrogen dioxide (NO ₂ ), nitrous oxide (dinitrogen monoxide) (N ₂ O), dinitrogen trioxide (N ₂ O ₃ ), dinitrogen tetroxide ( N ₂ O ₄ ) and dinitrogen pentoxide (N ₂ O ₅ ) are generic names for compounds composed of nitrogen and oxygen. Patent Document 3 is directed to a sterilant gas containing one or more nitrogen oxides of NO, NO ₂ , NO ₃ , N ₂ O ₃ , N ₂ O ₄ , N ₂ O ₅ , N ₂ O and mixtures thereof. Disclosed is a system for exposing a medical device to sterilize or decontaminate a medical device. Nitrogen oxide gas is generated from the sterilant gas generating composition to sterilize the medical device housed in a sealed sterilization chamber.

  Ethylene oxide gas is highly toxic to the human body, causing mucosal irritation of the upper respiratory tract, vomiting, and headache, and may be a carcinogen that damages DNA. For this reason, it is not preferable for health to suck the ethylene oxide gas remaining after the sterilization operation. In addition, ethylene oxide gas is a substance that is highly reactive, has a danger of ignition and explosion due to pressurization, and is very troublesome to handle. Furthermore, in the United States Pharmacopeia (USP), restrictions on the use of ethylene oxide gas are strengthened, and the need for alternative substances is increasing.

  In the isolator system of Patent Document 1, since hydrogen peroxide having a boiling point of 141 ° C. is heated and vaporized by a heater, a large amount of energy is required and the vaporized hydrogen peroxide vapor is very high temperature. If the isolator contains a heat-sensitive material (rubber or resin), the material may be denatured and deteriorated. In the system of Patent Document 1, the supply amount of hydrogen peroxide cannot be accurately controlled. When an excessive amount is supplied, the metal part in the isolator is corroded and the hydrogen peroxide remains after sterilization. When there is little, microorganisms and bacteria in an isolator cannot be killed completely. In addition, hydrogen peroxide is highly reactive and decomposes violently even at room temperature. Especially at high concentrations, it may ignite and explode due to self-decomposition. Is a very troublesome substance. It is very corrosive to metals.

  In the ozone sterilization apparatus shown in Patent Document 2, ozone is supplied to the sterilization area after adjusting the inside of the sterilization area not to normal pressure but to a negative pressure state. Moreover, since ozone is generated using air as a raw material, the generation efficiency of ozone is low, and it is necessary for a long time to fill the inside of a large volume sterilization area with a predetermined concentration of ozone, and the ozone generation amount is strictly controlled. And the ozone concentration in the sterilization area cannot be accurately managed. Since ozone gradually decomposes at room temperature and is chemically unstable, ozone must be generated on site immediately before use, and an ozone generator is required. For this reason, while the whole sterilization system becomes large, the running cost including initial cost and electricity bill increases. Furthermore, since ozone has a strong oxidizing power, it is extremely toxic at high concentrations, and when inhaled, the internal organs are oxidized and become eroded, which is a very dangerous substance.

In Patent Document 3, which uses nitrogen oxides as a sterilant, a diazeniumdiolate compound (R ³ —C (R ¹ ) _x (N ₂ O ₂ R ² ) _y ) and oxalic acid as a sterilant gas generating composition Is reacted in the gas generating chamber, or other sterilant gas generating composition and acid are reacted to generate nitrogen oxide gas. That is, since a plurality of substances are mixed in the gas generation chamber and nitrogen oxide gas is supplied to the sterilized space, the accurate generation amount of nitrogen oxide gas cannot be grasped and managed and supplied to the sterilized space. The concentration of nitrogen oxides that are produced may become unstable, and the medical device may not be sufficiently sterilized. On the other hand, if an excessive amount of nitrogen oxide is supplied, the nitrogen oxide adheres to the sterilized medical device at a high concentration, which is not preferable for safety. In addition, if it is necessary to mix a solid sterilant gas generating composition and an acid for each sterilization, it is realistic to use it for sterilization of a clean room or a medical device in an actual medical field. difficult. Furthermore, the use of acids is dangerous for handling, including transportation and storage.

JP 2006-68122 A JP 2001-340432 A Special table 2009-542333 gazette

  Then, an object of this invention is to provide the generation method and generator which generate | occur | produce gaseous nitrogen oxide from liquid nitrogen oxide with strong oxidizing power. Another object of the present invention is to provide a method for generating gaseous nitrogen oxides that can safely generate gaseous nitrogen oxides from liquid nitrogen oxides, and a gas nitrogen oxide generator that is easy to handle. Furthermore, an object of the present invention is to provide a compact and inexpensive method and apparatus for generating gaseous nitrogen oxide that does not require a large generator.

  The method for generating gaseous nitrogen oxides according to the present invention includes a process of pumping liquid dinitrogen tetroxide contained in a sealable container (1) to a heating device (6), and a liquid tetraoxidation by the heating device (6). A process of heating dinitrogen, a process of supplying heated liquid dinitrogen tetroxide from the heating device (6) to the injection device (2), and a vaporization space (3, 3 'under a pressure in the range of 90 kPa to 110 kPa ) Injecting or spraying liquid dinitrogen tetroxide from the injection device (2) to reduce the vaporization space (3, 3 ') below the saturated vapor pressure curve of nitrous oxide and vaporizing .

  The gaseous nitrogen oxide generator of the present invention accommodates a vaporization space (3, 3 ') maintained in a pressure range of 90 kPa to 110 kPa below the saturated vapor pressure curve of nitrous oxide and liquid nitrous oxide. And a container (1) that can be sealed and an injection device (2) for injecting or spraying a predetermined amount of liquid dinitrogen tetroxide in the container (1) into the vaporization space (3, 3 ′), A heating device (6) connected between the container (1) and the injection device (2) for heating the liquid dinitrogen tetroxide; The liquid dinitrogen tetroxide contained in the container (1) is pumped to the injection device (2) through the heating device (6), and the liquid dinitrogen tetroxide is vaporized from the injection device (2) ( 3,3 ′) is sprayed or sprayed, and the liquid nitrous oxide is reduced in pressure and vaporized.

  In the embodiment of the present invention, a liquid of dinitrogen tetroxide having a strong oxidizing power is pumped from the container (1) to the injection device (2) by a predetermined amount by the metering pump (4, 4 ′), and the injection device From (2), liquid dinitrogen tetroxide is discharged into the vaporization space (3, 3 ') under a pressure in the range of 90 kPa to 110 kPa, and vaporized instantaneously. The vaporized nitrogen oxide is dispersed and diffused as a gas, for example, in the entire vaporization space (3) of the clean room (20) to maintain the vaporization space (3, 3 ′) at a predetermined concentration, and the vaporization space (3, 3 ') Sterilize the whole quickly and efficiently. Further, for example, when an object such as a medical device (12) disposed in the vaporization space (3, 3 ′) in the chamber (30) is sterilized, the vaporized nitrogen oxide is removed from the object (12 ) And sterilize the object (12).

As used herein, “sterilization” refers to a process that completely destroys all types of proliferating microorganisms (mainly bacteria) or a process that converges to a completely sterile condition in which the growth potential of microorganisms is zero, ie, after sterilization. The existence probability index of microorganisms, etc .: Sterility Assurance level (SAL) is a treatment that reduces the level to 10 ^-6 or less. In molecular biology or biotechnology, "sterilization" is the function of microorganisms completely. It is required to be inactivated. Therefore, “sterilization” means “disinfection” that does not mean that the ability of pathogenic microorganisms is reduced but that all microorganisms are annihilated, or “sterilization” that does not include the target and extent of bacteria that disappear, but some bacteria disappear. Is different. Further, in the present invention, endotoxin, which is a dead body of bacteria, can also be effectively removed, and depyrogen treatment that is more advanced than sterilization can be performed.
In addition, since liquid dinitrogen tetroxide can be stored in the container (1) by applying a slight pressure at room temperature, it is possible to safely and easily store the liquid nitrous oxide in the container (1) without using a high pressure resistant container. It contains nitrous oxide and can be taken out and used. For this reason, compared with a gaseous sterilant, the transportation cost and maintenance cost of a liquid dinitrogen tetroxide can be reduced significantly, and also a small and inexpensive apparatus can be obtained.

  The method and apparatus for generating gaseous nitrogen oxide according to the present invention accurately measures dinitrogen tetroxide, which is a relatively safe liquid without mixing a plurality of substances, and efficiently dinitrogen tetroxide under almost atmospheric pressure. Therefore, dinitrogen tetroxide can be supplied safely at a stable concentration and the energy cost can be reduced. Furthermore, since an apparatus for generating nitrous oxide such as an ozone generator and a plasma apparatus is unnecessary, the entire apparatus can be reduced in size and the initial and operating costs can be reduced.

Schematic which shows 1st Embodiment of the gaseous nitrogen oxide generator by this invention Graph showing saturation vapor pressure curve of dinitrogen tetroxide (nitrogen dioxide) Schematic which shows 2nd Embodiment of the gaseous nitrogen oxide generator by this invention Schematic showing a third embodiment of the gaseous nitrogen oxide generator according to the invention using a two-way valve Schematic showing a fourth embodiment of the gaseous nitrogen oxide generator according to the present invention using a tube pump Schematic which shows 5th Embodiment of the gaseous nitrogen oxide generator by this invention Schematic which shows 6th Embodiment of the gaseous nitrogen oxide generator by this invention

  1 to 7 show an embodiment of a gaseous nitrogen oxide generator according to the present invention applied to a clean room (20) sterilization operation and a sterilization operation of a medical device (12) in a sterilization chamber (30) according to the present invention. explain.

The gaseous nitrogen oxide generator (sterilizer) (10) of the present invention used for the sterilization operation of the clean room (20) includes a container (1) for storing liquid nitrogen oxides, and a clean room under substantially atmospheric pressure ( 20) Predetermined (predetermined) amount from the injection device (2) that injects and vaporizes nitrogen oxide into the sterilized space (vaporization space) (3) and the outlet (7) of the container (1) And a metering pump (4, 4 ') for sucking the nitrogen oxide and feeding a predetermined amount of liquid nitrogen oxide toward the injection device (2). The injection device (2) is a nozzle or a valve. In this specification, “substantially under atmospheric pressure” is a pressure in the range of 90 kPa to 110 kPa. The liquid nitrogen oxide stored in the container (1) is selected from one or more of dinitrogen tetroxide, dinitrogen trioxide and dinitrogen pentoxide, with nitrous oxide being particularly preferred. Liquid dinitrogen tetroxide alone can produce a highly dispersible gas sterilant by simple pressure operation without mixing other substances. When dinitrogen tetroxide having a boiling point of 21 ° C. is stored at a temperature below the boiling point, high-pressure filling is not necessary, and there is no need to use a pressure-resistant container (1), and handling and storage are easy. Dinitrogen tetroxide has the following chemical equilibrium with nitrogen dioxide (NO ₂ ).

N ₂ O ₄ = 2NO ₂ -57.2 kJ

  In the chemical equilibrium formula, when the pressure is increased at a constant temperature, the reaction proceeds to the left and the proportion of dinitrogen tetroxide increases. Conversely, when the pressure is lowered, the reaction proceeds to the right and the proportion of nitrogen dioxide increases. Dinitrogen tetroxide itself is colorless, but exhibits a color derived from nitrogen dioxide through chemical equilibrium, that is, reddish brown for gas and yellow for liquid. In the present invention, a sterilizing agent obtained by combining two or more kinds of dinitrogen tetroxide, dinitrogen trioxide and nitrous oxide can also be used.

  The metering pump (4, 4 ') is selected from a diaphragm pump, a piston pump, a plunger pump and a tube pump, and a piston pump is particularly preferable. With a metering pump (piston pump (4)), a predetermined amount of liquid nitrogen oxide is accurately weighed and taken out from the outlet (7) at the bottom of the container (1) and accurately weighed liquid nitrogen Oxide is pumped to the injector (2). The pressure value at this time is an absolute pressure of 110 kPa to 50000 kPa immediately before the injection device (2). When the pressure is 110 kPa or less, the liquid nitrogen oxide is weakly pumped and the injection into the space to be sterilized (3) is weak, so that the vaporization and dispersion of the nitrogen oxide is insufficient, and the diffusion of the nitrogen oxide is slow. The concentration distribution is non-uniform. When the pressure is higher than 50000 kPa, the cost for producing the injection device (2) suitable for high pressure is high, and the metering pump (4, 4 ') is also increased in size.

  The injection device (2) has an injection port (2a) whose opening degree (injection hole area) can be adjusted, and injects nitrogen oxide from the injection port (2a) into a clean room (20) at a substantially atmospheric pressure level. Or vaporize by spraying. A popular injection device (2) having an injection port (2a) in which the nozzle hole area cannot be changed can also be used. When sprayed into the clean room (20) from the spray device (2), the concentration of nitrogen oxides becomes uniform and adheres not only to microorganisms and bacteria floating in the clean room (20) but also to the walls and floor of the clean room (20). Sterilized microorganisms and bacteria can be reliably sterilized.

  In the present embodiment, the first port (5a) connected to the container (1), the second port (5b) connected to the metering pump (4, 4 ′), and the injection device (2) A three-way valve (5) having a third port (5c) to be connected is provided. Although not particularly limited, a ball valve having a spherical valve body (15) and a flow path (16) in the valve body (15) and having a simple internal structure and capable of suppressing microbial contamination is used as the three-way valve (5). . The three-way valve (ball valve) (5) is connected to the container (1) for the metering pump (4, 4 '), but is disconnected from the injector (2), and the piston pump (4) However, the communication with the container (1) is cut off, but the discharge state with the injection device (2) is switched as necessary. For example, a plunger pump, a diaphragm pump or a rotary tube pump can be used as the metering pump (4, 4 ').

  A heating device (6) is provided between the metering pump (4, 4 ') and the injection device (2) to heat the liquid nitrogen oxide and inject the nitrogen oxide from the injection device (2). That is, referring to the saturated vapor pressure curve of dinitrogen tetroxide (nitrogen dioxide) in FIG. 2, the liquid nitrogen oxide in a state filled with the container (point O2) is added by a metering pump (4, 4 '). By pressing (arrow A), heating by the heating device (6) (arrow B), and releasing into the clean room (20) under almost atmospheric pressure (arrow C), the vaporization of nitrogen oxide proceeds rapidly, The clean room (20) can be efficiently filled with gaseous nitrogen oxides.

  The heating device (6) includes a pipe line (6a) through which liquid nitrogen oxide passes and a housing (6b) surrounding the pipe line (6a), and has a spiral shape, fin shape, coil shape, and serpentine shape. A heating medium in the housing (6b) such as steam or a heating fluid is brought into contact with the outer surface of the pipe (6a) having a large surface area, and the liquid nitrogen oxide passing through the inside of the pipe (6a) is contacted by heat contact. Heat. Heating efficiency can be improved by using a spiral pipe (6a) having a large contact area with the heating medium. Heating elements such as nichrome wires and film heaters provided on the outer surface of the pipe line (6a) can also be used as the heating device (6), and part of the pipe line (6a) is electrically insulated and energized from both insulated ends. The pipe (6a) itself may be a heating element. Further, an electrode may be installed inside the pipe (6a) (in the fluid), and a voltage may be applied to heat the internal fluid directly with Joule heat. The liquid nitrogen oxide is heated to 25 ° C. to 150 ° C. by the heating device (6) and supplied to the spraying device (2).

  The sterilization operation of the clean room (20) using liquid nitrogen oxide (dinitrogen tetroxide) will be described below with reference to FIGS.

  First, liquid dinitrogen tetroxide is placed in the container (1). Dinitrogen tetroxide is a strong oxidizer, but if it is pressurized and filled into the container (1) at a temperature of 21 ° C. (boiling point) or less and an absolute pressure of about 200 kPa (about 2 atmospheres) (FIG. 2, point O1 → Point O2) can be safely stored in a liquid state. On the other hand, the clean room (20) to be sterilized is kept sealed so that nitrogen oxides do not leak outside.

  A predetermined (predetermined) amount of liquid dinitrogen tetroxide is sucked into the metering pump (piston pump) (4) from the outlet (7) formed in the bottom of the container (1), and the piston pump ( 4. Accurately and quickly measure liquid nitrous oxide in the variable volume (cylinder) (4a) of 4) while temporarily storing it. At this time, the three-way valve (5) communicates with the container (1) with respect to the communication state of the first port (5a) and the second port (5b), that is, the metering pump (4, 4 ′). Is in a suction state that blocks communication with the injection device (2).

  Next, the communication state between the second port (5b) and the third port (5c), that is, the communication with the container (1) with respect to the metering pump (4, 4 ') is cut off, but the injection device ( 2) Switch the three-way valve (5) to a discharge state communicating with 2), pump the liquid nitrous oxide that was temporarily stored from the metering pump (4,4 ') (arrow A in FIG. 2), and the heating device ( According to 6), dinitrogen tetroxide is supplied to the injection device (2) while heating (arrow B in FIG. 2).

  A predetermined amount of dinitrogen tetroxide pumped from the metering pump (4, 4 ') is transferred to the sterilized space (3) in the clean room (20) from the injection port (2a) of the injection device (2). It is injected (arrow C in FIG. 2). Since the space (3) to be sterilized in the clean room (20) is substantially at atmospheric pressure, the pressurized and heated liquid dinitrogen tetroxide is rapidly vaporized and dispersed in the clean room (20). The dispersed gaseous nitrogen oxides are a mixture of dinitrogen tetroxide and nitrogen dioxide.

  In the present embodiment, the amount of nitrogen oxide supplied to the sterilized space (3) of the clean room (20) can be strictly measured and managed by the metering pump (4, 4 ′), so that the sterilized space (3 ) Nitrogen oxide concentration can always be kept constant. Depending on the capacity of the clean room (20), the state in which nitrogen oxides are present is maintained for several minutes to several hours, and microorganisms and bacteria floating in the clean room (20) or adhering to the wall surface are completely killed.

  After completion of the sterilization operation of the clean room (20), an operation of returning the liquid nitrogen oxide staying in the pressure feeding pipe (8) between the three-way valve (5) and the injection device (2) to the container (1) is performed. That is, when the metering pump (4, 4 ′) is sucked in a state where the metering pump (4, 4 ′) and the injection device (2) communicate with each other, nitrogen oxide in the pressure feeding pipe (8) is converted into the metering pump (4, 4 ') In the cylinder (4a). Next, the three-way valve (5) is switched to a state where the metering pump (4, 4 ') and the container (1) communicate with each other, and the nitrogen oxide in the cylinder (4a) is sent toward the container (1). On the other hand, cleaning gas (nitrogen gas or air) is supplied into the clean room (20) from an inlet (not shown), and nitrogen oxides in the clean room (20) are removed by ventilation. Nitrogen oxide is removed by the filter (11) through the discharge pipe (9) connected to the clean room (20), and the cleaning gas is continuously supplied to the clean room (20) to remove nitrogen oxide by the filter (11). If removed, the nitrogen oxides can be completely removed from the clean room (20). In the present embodiment, the sterilization process of the clean room (20) is exemplified, but the present invention is not limited to a clean room, and can be applied to a clean booth, an isolator, a hospital room, and an operating room.

  Hereinafter, a second embodiment in which the gaseous nitrogen oxide generating apparatus and the generating method according to the present invention are applied to the medical device (12) in the sterilization chamber (30) will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and only components different from those in the first embodiment will be described in detail.

  In the sterilization space (3 ') in the sterilization chamber (30), a medical device (12) or a pharmaceutical container as an object is arranged. For example, the present invention can be applied to medical devices (12) and pharmaceutical containers made of any material that does not deteriorate against nitrogen oxides, such as metal, plastic, rubber, etc., and the medical device (12) includes, for example, a scalpel, forceps, scissors, tweezers Surgical instruments such as, flexible and rigid endoscopes, thermometers, stethoscopes, ophthalmoscopes, otoscopes and other diagnostic instruments, catheters, syringes, medical tubes and other therapeutic instruments, pacemakers, implantable aggregates, surgery Includes implantable medical devices such as industrial bolts. The pharmaceutical container includes, for example, a plastic container, a glass container, a vial, a spray container, an aluminum tube, a rubber stopper, an elastomer resin part, and an injection needle. The present invention can be applied not only to pre-sterilization but also to in-use sterilization immediately before use. A lid (not shown) is attached to the space to be sterilized (3 ') in which the medical device (12) is disposed, and the space to be sterilized (3') is held in a sealed state.

  The pressure of the space to be sterilized (3 ') in the sterilization chamber (30) is approximately atmospheric pressure. In the same manner as in the first embodiment, liquid nitrogen oxide is pumped from the sterilization apparatus (10), and the nitrogen oxide is sterilized from the injection apparatus (2) disposed in the sterilization chamber (30). Released to (3 '). The released nitrogen oxides are vaporized and dispersed in the space to be sterilized (3 ') to sterilize the medical device (12). Gaseous nitrogen oxides are instantaneously dispersed in the space to be sterilized (3 '), diffusing into the details of the medical device (12) and sterilizing the surface of the complex shaped medical device (12) quickly and completely can do. In the present invention, since the amount of liquid nitrogen oxide supplied to the sterilization chamber (30) using the metering pump (4, 4 ′) can be strictly controlled, the quantity, size, material, The supply amount of nitrogen oxides can be appropriately selected according to the degree of contamination.

  In the first and second embodiments, the three-way valve (5) that connects and shuts off the container (1), the metering pump (4, 4 ') and the injection device (2) is used. In the third embodiment shown in FIG. 4 without using the valve (5), a pair of two-way valves (17a, 17b) is used. That is, a suction valve (17a) is provided between the container (1) and the metering pump (4, 4 ′), and a delivery valve (17b) is provided between the metering pump (4, 4 ′) and the injection device (2). Is provided. In the suction state where the intake valve (17a) is opened and the delivery valve (17b) is closed, the container (1) is contacted but the communication with the injection device (2) is interrupted, and liquid nitrogen oxide is removed from the container (1). The sucked and sucked nitrogen oxide is temporarily stored in the metering pump (4, 4 ′). On the other hand, in the suction state in which the intake valve (17a) is closed and the delivery valve (17b) is opened, the communication with the container (1) is cut off, but the communication with the injection device (2) is made, and the metering pump (4, 4 ') The accommodated nitrogen oxide is pumped to the injection device (2). In the present embodiment, diaphragm valves that use the reciprocating motion of the diaphragm (19) are used as the suction valve (17a) and the delivery valve (17b), but there is no particular limitation. By alternately switching the opening and closing operations of the suction valve (17a) and the delivery valve (17b), the suction state and the discharge state can be switched.

  In the first to third embodiments, the piston pump (4) that temporarily stores and measures liquid nitrogen oxides is used as the metering pump. However, in the fourth embodiment shown in FIG. Using the tube pump (4 ′), nitrogen oxide is directly fed from the container (1) to the injection device (2). The tube pump (4 ') has a flow rate proportional to the amount of rotation of the rotating body (4a'), and can pump a fixed amount.

  In the fifth embodiment shown in FIG. 6, a piston (4), a tube pump (4 ′), a three-way valve (5), a suction valve (17a), and a delivery valve (17b) are not used. ) And the sterilized space (3), an introduction valve (55) is provided in the pressure feed pipe (8), and a pressure gauge (56) is disposed upstream of the introduction valve (55). Since the unit time flow rate of liquid nitrogen oxide is determined by the pressure value of the pressure gauge (56) and the inner diameter of the pressure feed pipe (8), by controlling the opening and closing time of the introduction valve (55) according to the pressure value, The supply amount of liquid nitrogen oxide delivered to the space (3) can be easily and accurately controlled.

  In the sixth embodiment shown in FIG. 7, a sterilization apparatus is shown in which the container (1) is preliminarily filled with liquid nitrogen oxide by a necessary amount. In this embodiment, when the space to be sterilized (3) is sterilized, by opening the introduction valve (55) in a state where the container (1) is connected to the space to be sterilized (3) through the pressure feeding tube (8), All liquid nitrogen oxides are discharged from the container (1). For this reason, a constant amount of liquid nitrogen oxide can always be supplied to the sterilized space (3) without performing flow rate control, and the sterilized space (3) can be reliably sterilized. The container (1) may be a small cylinder. Also in this embodiment, the piston pump (4), the tube pump (4 '), the three-way valve (5), the suction valve (17a), and the delivery valve (17b) are not required.

  In the first to sixth embodiments, the introduction valve (55) is disposed between the container (1) and the heating device (6). However, the heating device (6) and the space to be sterilized (3) An introduction valve (55) may be provided between them. Further, the injection device (2) formed at the inlet of the sterilized space (3) with or without the introduction valve (55) may be used as the valve.

  An embodiment in which a sterilization test of microorganisms was performed by the gas nitrogen oxide generator according to the present invention and the generation method thereof will be described below.

Sterilization test SCBI (Self-Contained Biological Indicator) was placed in a space to be sterilized (3, 3 ') of about 8 L (20 cm x 20 cm x 20 cm) in a glass chamber. SCBI is a sterilization test kit in which a filter paper with attached microorganism spores and a glass capsule containing a culture solution are housed in a small test tube and sealed with aeration filter paper. Liquid dinitrogen tetroxide (N ₂ O ₄ ) is supplied to the sterilized space (3, 3 ') where SCBI is placed at a pressure higher than atmospheric pressure by a metering pump (4, 4'). Vaporized. Sterilization was performed by maintaining the nitrous oxide concentration in the space to be sterilized (3,3 ′) at 18500 ppm (36.28 mg / L) for 20 minutes.

  After sterilization, SCBI was taken out from the space to be sterilized (3, 3 '), and dinitrogen tetroxide was removed from the small test tube of SCBI by pressure operation. Next, the glass capsule was broken in a small test tube, the filter paper was immersed in the culture solution, and the sterilized SCBI was cultured in a 58 ° C. incubator for about 24 hours (sterilization SCBI). On the other hand, SCBI which was not sterilized and left in the atmosphere for 20 minutes was similarly cultured in a 58 ° C. incubator for about 24 hours (non-sterilized SCBI).

Test result The sterilization SCBI showed no change, indicating that the microorganisms were not growing, and it was confirmed that the sterilization was sufficiently performed. On the other hand, non-sterilized SCBI showed discoloration, and it was confirmed that microorganisms were growing without being sterilized.

  The apparatus and method for generating gaseous nitrogen oxides according to the present invention are applicable not only to the fields of pharmaceutical, medical and food, but also to the generation and sterilization of gaseous nitrogen oxides in the fields of electronics industry, precision machinery industry, mainly semiconductors. can do.

  (1) ・ ・ Container, (2) ・ ・ Injection device, (2a) ・ ・ Injection port, (3,3 ') ・ ・ Vaporization space (space to be sterilized), (4,4') ・ ・ Quantitative pump, (4a) ・ ・ Variable volume part, (5) ・ ・ Valve device (three-way valve), (6) ・ ・ Heating device, (6a) ・ ・ Pipe, (7) ・ ・ Outlet, (12) ・ ・ Target Things (medical equipment), (17a) ・ ・ Valve device (suction valve), (17b) ・ ・ Valve device (delivery valve),

Claims (15)

A process of pumping liquid dinitrogen tetroxide contained in a sealable container to a heating device;
A process of heating liquid dinitrogen tetroxide with a heating device;
Supplying heated liquid dinitrogen tetroxide from the heating device to the injector;
Including a process of injecting or spraying liquid nitrous oxide in a vaporizing space under a pressure in a range of 90 kPa to 110 kPa from a spraying device, reducing the pressure below the saturated vapor pressure curve of nitrous oxide and vaporizing the vaporized space. A method for generating gaseous nitrogen oxides.   The process of pumping liquid nitrous oxide to the heating device is a process of sucking a predetermined amount of liquid nitrous oxide from the container by a metering pump and pumping the sucked liquid nitrous oxide to the heating device The method for generating gaseous nitrogen oxides according to claim 1, comprising: A process of opening a space between the container and the metering pump by the valve device, closing a space between the metering pump and the vaporization space, and sucking a predetermined amount of liquid nitrous oxide from the container by the metering pump;
The valve device closes the container and the metering pump, opens the metering pump and the injection device, and supplies a predetermined amount of liquid dinitrogen tetroxide to the injection device via the heating device. The method for generating gaseous nitrogen oxides according to claim 2, comprising the step of:   The process of controlling the supply amount of liquid nitrous oxide to the injection device while controlling the opening and closing time of the introduction valve according to the pressure value upstream of the introduction valve provided between the container and the heating device The gaseous nitrogen oxide generation method of Claim 1 containing. The process of pressurizing and filling liquid nitrous oxide in a cylinder as a container in advance as much as necessary, and storing the liquid nitrous oxide in the cylinder;
Opening the introduction valve or the injection device provided between the cylinder and the vaporization space in a state where the cylinder is connected to the injection device through the pressure feed pipe via the heating device for heating the liquid dinitrogen tetroxide ;
The method for generating gaseous nitrogen oxides according to claim 1, comprising a step of pumping a certain amount of liquid dinitrogen tetroxide from a cylinder through a heating device to an injection device. A vaporization space maintained in a pressure range of 90 kPa to 110 kPa below the saturated vapor pressure curve of nitrous oxide;
A container containing liquid nitrous oxide and capable of being sealed;
An injection device for injecting or spraying a predetermined amount of liquid dinitrogen tetroxide in a container under pressure in the vaporization space;
A heating device connected between the container and the injection device for heating the liquid dinitrogen tetroxide,
Liquid dinitrogen tetroxide contained in a container is pumped to the injection device via the heating device, and liquid dinitrogen tetroxide is injected or sprayed from the injection device into the vaporization space to obtain liquid dinitrogen tetroxide. A gaseous nitrogen oxide generator characterized by being depressurized and vaporized. A metering pump having a variable volume part for temporarily storing liquid dinitrogen tetroxide contained in a container and supplying a predetermined amount of liquid dinitrogen tetroxide pressurized from the variable volume part to the vaporization space When,
A valve device connected between the variable volume of the metering pump and the container and between the variable volume and the vaporization space;
During the suction of the metering pump, the valve device shuts off between the metering pump and the vaporization space, the metering pump introduces liquid dinitrogen tetroxide from the container into the variable volume,
7. The gaseous nitrogen according to claim 6, wherein when the metering pump is delivered, the valve device shuts off between the container and the metering pump, and the metering pump pumps liquid dinitrogen tetroxide from the variable volume portion to the vaporization space. Oxide generator.   The gaseous nitrogen oxide generator according to claim 7, wherein the valve device is a ball valve.   The gaseous nitrogen oxide generator according to claim 7, wherein the valve device is a suction valve and a discharge valve each having a diaphragm.   The gaseous nitrogen oxide according to any one of claims 6 to 9, wherein the injection device has an injection port for spraying and vaporizing liquid dinitrogen tetroxide in the vaporization space, and the injection hole area of the injection port can be adjusted. Generator.   The gaseous nitrogen oxide generator according to any one of claims 7 to 9, wherein the metering pump is selected from a diaphragm pump, a piston pump, a plunger pump, and a tube pump. An introduction valve provided between the container and the heating device;
A pressure gauge provided on the upstream side of the introduction valve,
The gaseous nitrogen oxide generator according to claim 6, wherein the supply amount of liquid dinitrogen tetroxide to the vaporization space is controlled by controlling the opening and closing time of the introduction valve according to the pressure value of the pressure gauge. A pressure-feed pipe connecting the cylinder as a container and the vaporization space;
An introduction valve provided between the cylinder and the vaporization space,
Claims: By controlling the opening and closing time of the introduction valve, the liquid dinitrogen tetroxide preliminarily filled with a required amount is discharged from the cylinder, and a certain amount of liquid dinitrogen tetroxide is pumped to the vaporization space. 6. The gaseous nitrogen oxide generator according to 6. The heating device includes a pipe line connected between the container and the injection device, and a housing surrounding the pipe line,
The gaseous nitrogen oxide generator according to claim 6, wherein the liquid nitrous oxide that passes through the inside of the pipe line is in thermal contact with the heating medium in the housing. Vaporizing space is gaseous nitrogen oxide generating apparatus according to any one of claims 6-14 vaporized nitrogen tetroxide is intended to accommodate the object to be contacted.

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