BR122013010289B1 - METHOD OF CONTROL OF AN UNWANTED CONDENSATION OF HYDROGEN PEROXIDE IN A STERILIZATION CHAMBER AT A PRE-SELECTED TEMPERATURE - Google Patents

Description

(54) Title: METHOD OF CONTROL OF AN UNWANTED HYDROGEN PEROXIDE CONDENSATION IN A STERILIZATION CHAMBER AT A PRE-SELECTED TEMPERATURE (51) lnt.CI .: A61L 2/20; A61L 2/24; A61L 2/26 (30) Unionist Priority: 09/30/2009 US 61 / 247,197 (73) Holder (s): TSO3 INC.

(72) Inventor (s): SYLVIE DUFRESNE; JEAN-MARTIN VALLIERES; BRUNO TREMBLAY (85) National Phase Start Date: 26/04/2013

1/45 “METHOD OF CONTROL OF UNWANTED HYDROGEN PEROXIDE CONDENSATION IN A PRE-SELECTED TEMPERATURE STERILIZATION CHAMBER”, divided from Invention Patent Application No. BR112012006740-0 of 29/09/2010 which in turn claims priority of the US Provisional Patent Application SN. 61 / 247.197, required on September 30, 2009, and entitled STERILIZATION APPARATUS AND METHOD and being a continuation order of the North American Order SN. 12 / 893,742 required on September 29, 2010 and entitled APPLIANCE AND STERILIZATION METHOD, the contents of which are incorporated into this application in its entirety.

[0001] The present invention generally relates to sterilization methods and apparatus. More particularly, the present invention relates to a method of vacuum sterilization using gaseous biocides.

[0002] Sterilization is the destruction of any virus, bacteria, fungus or other microorganism, whether in a dormant or vegetative spore and being defined by a 10 ' ⁶ reduction in the level of bacteria. Conventional sterile processing procedures for medical instruments involve high temperature (such as dry heat and steam units) or chemicals (such as ethylene oxide gas, hydrogen peroxide or ozone).

[0003] Sterilization methods and apparatus using gaseous sterilizers are well known. Sterilizers using hydrogen peroxide as a sterilizer are widely used. Hydrogen peroxide is usually supplied as an aqueous solution and evaporated before injection into a sterilizer sterilization chamber, by heating the solution, or by applying a vacuum to the sterilization chamber, or both. After the solution has evaporated, the sterilization atmosphere in the sterilization chamber includes water vapor and hydrogen peroxide gas. Is

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2/45 disadvantage of this process is that water vapor tends to condense on articles in the chamber when sterilizing. The resulting layer of condensed water in the articles to be sterilized interferes with the sterilization action of hydrogen peroxide. Numerous device and process modifications have been developed to solve this problem, all of which aim to limit the relative humidity in the sterilization atmosphere during the sterilization process.

[0004] However, these changes invariably increase the cost of operation and / or times of the sterilization cycle.

[0005] Sterilization processes using both hydrogen peroxide gas and ozone gas have been used, but with unsatisfactory results especially in relation to the sterilization of articles with long internal lumens, such as gastrocopes and colonoscopes, and in relation to the cycle and cost sterilization. Although ozone-based processes are satisfactory with regard to sterilizing articles with long lumens, compatibility with the material presents a problem. Hydrogen peroxide-based processes are generally unsatisfactory with regard to sterilizing long lumens. Unwanted condensation of hydrogen peroxide in the article to be sterilized reduces the efficiency of sterilization.

[0006] Thus, a method and apparatus are desired to solve at least one of the disadvantages of known sterilization processes using gaseous sterilizers.

[0007] It is an objective of the present invention, to mitigate at least one disadvantage of previous sterilization processes using gaseous sterilizers.

[0008] In a first aspect, a method of controlling hydrogen peroxide condensation in a sterilization chamber at a pre-selected temperature is revealed. The method includes the steps of

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3/45 maintaining the sterilization chamber at a vacuum pressure in which the hydrogen peroxide boils at a pre-selected temperature, with successive evaporation pulses of hydrogen peroxide and injection of evaporated hydrogen peroxide into the chamber, thereby the volume of each pulse of hydrogen peroxide is less than 75 pL. [0009] In a second aspect, the volume of each pulse is less than 35pL.

[0010] In a third aspect, the volume of each pulse is less than 20pL.

[0011] Other aspects of the present invention will become related to those skilled in the art which are in the state of the art through a review of the specific configurations of this invention with the accompanying figures.

[0012] Configurations of the present device, systems and methods will now be described in an exemplary and non-limiting manner, in which:

- Figure 1 shows a schematic diagram of an apparatus according to this invention, the illustrated parts of the apparatus being listed in Table III;

- Figure 2 shows a schematic diagram of a hydrogen peroxide delivery system according to this invention, the illustrated parts of the system being listed in Table III;

- Figure 3 is a flow diagram of a preferred method of sterilization according to this invention;

- Figure 4 is a graph illustrating a first exemplary sterilization cycle according to this invention;

- Figure 5 is a graph illustrating a second exemplary sterilization cycle according to this invention;

- Figure 6 is a graph illustrating a third exemplary sterilization cycle according to this invention;

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- Figure 7 shows an exemplary configuration of a hydrogen peroxide supply unit according to this invention;

- Figure 8 shows an exemplary configuration of a measuring evaporation set for a hydrogen peroxide reservoir according to this invention;

- Figure 9 is a schematic diagram of a control system for an apparatus according to this invention;

Figure 10a is a perspective view of a sterilizing container according to this invention;

Figure 10b is a cross-sectional view of the container of Figure 10a;

Figure 10c is a side elevation view of the container of Figure 10a; and

- Figure 10d is an enlarged detail B of the container shown in Figure 10b.

Generally, the present application provides a method for sterilizing an article in a gaseous sterilization atmosphere by sequentially adding evaporated hydrogen peroxide and particularly to a method of measuring hydrogen peroxide vapor in an evacuated chamber. The method includes the steps of maintaining the sterilization chamber at a vacuum pressure below the pressure at which the hydrogen peroxide will fever at a pre-selected temperature, evaporating in successive pulses of hydrogen peroxide, and injecting the evaporated hydrogen peroxide into the chamber in volume pulses in which it is selected to prevent unwanted condensation of hydrogen peroxide at a pre-selected temperature.

As will be discussed further below, the hydrogen peroxide solution injected into the sterilization chamber in a vapor form will condense on the article to be sterilized. However, condensation of hydrogen peroxide interferes with the sterilization of long lumens, since the

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5/45 hydrogen peroxide is removed from the vapor phase during condensation. Thus, in the sense that hydrogen peroxide penetrates long lumens, hydrogen peroxide should be kept in the vapor phase as much as possible and condensation avoided during the injection of hydrogen peroxide. This is achieved according to the present invention by controlling the volume of the individual hydrogen peroxide injection pulses. In a configuration of the present invention, the volume of each pulse of hydrogen peroxide is less than 75 μΙ_. In another configuration, the volume of each pulse of hydrogen peroxide is less than 35 μΙ_. In an additional configuration, the volume of each hydrogen peroxide is less than 20 μΙ_.

This hydrogen peroxide concentration control method can be used in a sterilization method as illustrated in the flow diagram in Figure 3 and in the cycle graphs in Figures 4 to 6, where an article is sterilized by its sequential exposure to hydrogen peroxide. hydrogen and ozone. The article is preferably exposed first under vacuum to an evaporated aqueous solution of hydrogen peroxide and subsequently to a gas containing ozone. Exposure to evaporated hydrogen peroxide is accomplished by controlling the unwanted condensation of hydrogen peroxide. Preferably, the exposure is carried out without reducing the water vapor content in the sterilization atmosphere, the water vapor content being derived from the aqueous solvent of the hydrogen peroxide solution and from the decomposition of the hydrogen peroxide in water and oxygen. Most preferably, the complete sterilization process is achieved while the chamber remains sealed and without removing any component from the sterilization atmosphere. For this purpose, the chamber is initially evacuated at a first vacuum pressure sufficient to cause evaporation of aqueous hydrogen peroxide at the temperature of the chamber's atmosphere. THE

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The chamber is then sealed and the hydrogen peroxide or ozone-containing gas is sequentially added to the chamber and kept in the chamber for a pre-selected exposure time. Any removal of any components in the sterilization atmosphere is halted during the addition of sterilizers and for the duration of the exposure time.

The aqueous hydrogen peroxide solution is evaporated and directly injected into the sterilization chamber without any measures to reduce the water vapor content. The inventors of the present application have surprisingly found that the amount of sterilizers used and the length of the sterilization cycle can be significantly reduced, when any of the steps to reduce the water vapor content are followed by an ozone sterilization step, since the water vapor generated during the hydrogen peroxide sterilization step can be used to sufficiently moisten the atmosphere in the chamber to perfect the ozone sterilization step. Much smaller amounts of hydrogen peroxide and ozone can be used than in processes known to the state of the art using the same sterilizers, while still achieving complete sterilization. In addition, the required amounts of sterilizers according to the present invention are less than would be expected from the simple use of two sterilizers in the same cycle. Thus, keeping the chamber sealed through all the sterilization steps without any measurements to control the humidity in the sterilization atmosphere will result in a synergistic effect.

A sterilizer according to this invention as illustrated schematically in Figure 1 generally operates as follows. An article to be sterilized (not shown) is placed in the sterilization chamber 10 and the chamber being sealed. A vacuum is applied to chamber 10. The evaporated hydrogen peroxide solution is supplied in the

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7/45 sterilization 10 of a distribution unit 30 (see Figure 8) which will be discussed in more detail below. The evaporated hydrogen peroxide supplied in the chamber provides partial sterilization of the article. Medical grade oxygen is subjected to an ozone generator 22 to an electric field, which converts oxygen into ozone-containing gas. The ozone-containing gas is then fed into chamber 10, which has been moistened by injecting the evaporated hydrogen peroxide solution and decomposing the hydrogen peroxide into free radicals (hydroxyls), water and oxygen. The ozone-containing gas ends the sterilization of the article. The remaining sterilizing gases are subsequently decomposed into water and oxygen using a 52 catalyst. The only residues left at the end of the sterilization cycle are oxygen and clean water.

The ozone sterilization method of this invention is preferably carried out at room temperature and, therefore, does not require substantially any aeration or cooling of the sterilized articles so that they can be used immediately following the sterilization cycle. In addition, the gases used diffuse more quickly in long lumens to be sterilized, sometimes reducing the cycle required for sterilization. This allows hospitals to reduce the cost of expensive medical device maintenance. The sterilization method of the invention offers several advantages. It does not produce toxic waste, does not require the handling of dangerous gas cylinders, and does not pose any threat to the health of users of the environment. Stainless steel instruments and heat sensitive instruments can be treated simultaneously, which for some users who for obvious reasons need two separate sterilizers. The preferred sterilization apparatus according to this invention as illustrated schematically in Figure 1, includes a sterilization chamber 10 that can be sealed to contain a vacuum. This is achieved with an access door 12, which can be selectively opened for access from the

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8/45 chamber and that seals the chamber in the closed condition. The device also includes an ozone generator 22 to supply ozone-containing gas to the sterilization chamber, a hydrogen peroxide distribution unit 30 to supply hydrogen peroxide to the sterilization chamber 10, and a vacuum pump 40 (CM- 005—52 TS03, Inc.). The vacuum pump 40 is used to apply sufficient vacuum to the sterilization chamber 10 to increase the penetration of the sterilizing gas and to be able to generate the evaporated hydrogen peroxide solution at a temperature below the temperature inside the chamber. sterilization. The vacuum pump 40 in the preferred configuration is capable of producing sufficient vacuum in the sterilization chamber to decrease the boiling point of the water in the chamber below the current atmosphere temperature in the chamber. In the preferred apparatus, the vacuum pump is capable of producing a vacuum of 1 Torr (1.33mbar). The ozone produced in the ozone generator 22 is destroyed in an ozone catalyst 52 in which the ozone-containing gas is fed both after passing through the sterilization chamber 10 and directly from the ozone generator 22 through the bypass valve 29b. The ozone catalyst 52 (AM-004-001, TSO ₃ Inc.) is connected in series after the vacuum pump 40 prevents ozone gas from escaping into the environment. The ozone-decomposing material in the preferred catalyst 52 is carolite. For economic and practical reasons, it will be preferred to use a catalyst for decomposing ozone in the exhausted sterilization gas of the sterilization chamber 10. The catalyst destroys hydrogen peroxide and ozone on contact, transforming them into oxygen and water in a certain amount of heat being produced. Such catalysts and their manufacture are well known to a person skilled in the art with knowledge of the state of the art of ozone generators and it will not be necessary to describe it here. In addition, other means for the destruction of ozone and hydrogen peroxide contained in the sterilizing gas will be

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Apparent 9/45 to a technician in the field with knowledge of the state of the art. For example, the gas can be heated for a pre-selected time to a temperature at which the sterilizing decomposition is accelerated, for example, at 300 ° C for a period of 3 seconds.

The hydrogen peroxide distribution unit 30 includes a reservoir 220 (AM-213-010, TSO ₃ Inc.), a measurement unit 240, and an evaporator unit 260 (FM-213-003, TSO ₃ Inc.) directly connected to sterilization chamber 10 through conduit 280 (AM-213-003, TSO ₃ Inc.). Reservoir 220 is equipped with a level 222 sensor to always ensure a sufficiently high level of hydrogen peroxide for the execution of another sterilization cycle. A hydrogen peroxide solution (3-59%) is supplied to the reservoir of a hydrogen peroxide supply unit 200 (see Figure 7), which will be discussed in detail below. The hydrogen peroxide solution is supplied in supply unit 200 from a sealed bottle 180 (see Figure 7). The evaporated hydrogen peroxide solution produced in the evaporator unit 260 directly enters the sterilization chamber 10 without any restriction of intermediate flow or valve. The evaporator unit is preferably equipped with a heating device (not shown) that keeps the temperature of the hydrogen peroxide solution high enough to achieve a higher evaporation rate and prevent the solution from freezing.

The ozone generator 22 (OZ, model 14a, TSO ₃ Inc.) is a corona discharge type and is cooled to decrease the ozone decomposition rate, well known in the state of the art. Ozone generation is associated with loss of energy in the form of heat. Since heat accelerates the decomposition of ozone into oxygen, it must be removed as quickly as possible by cooling the ozone generator 22. The ozone generator in the device is kept at a relatively low temperature of 3 to 6 ° C for

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10/45 um, cooling system 60, which is an indirect cooling system with chilled water recirculation, or a direct cooling system with an air cooling unit or a cooling unit for cooling (not shown). The cooling system is preferably maintained at a temperature of 3 to 6 ° C. In the preferred configuration, the cooling system is maintained at 4 ° C so that the ozone-containing gas generated by the generator 22 is at room temperature around 20 to 35 ° C. Thus, the ozone-containing gas entering the sterilization chamber for moistening and sterilization is maintained at an ambient temperature of 20 to 35 ° C. This means that ozone decomposition is minimized and the sterilization process is more efficient . The ozone generator 22 is preferably supplied with medical grade oxygen. Oxygen can also be supplied directly to the sterilization chamber 10 through the oxygen supply valve 21. The device can be connected to an oxygen outlet wall common in hospitals or to an oxygen cylinder or any other source capable of supplying oxygen. quality and flow are required. The oxygen supply of generator 22 takes place through a filter 23, a pressure regulator 24, a flow meter 25 and a shut-off valve 26. The generator is protected against oxygen under pressure by a safe pressure switch 27. The mixture oxygen-ozone generated by the generator 22 is directed to the sterilization chamber 10 through a flow regulating orifice 28 and a mixture supply solenoid valve 29a. The mixture can also be supplied directly to the ozone catalyst 52 via a bypass solenoid valve 29b (optional). In a preferred configuration in which the 125 liter volume sterilization chamber is used, pressure regulator 24 and regulator valve 28 preferably control oxygen inlet at a pressure of approximately 13.8 kPa (2 psig) and a flow rate approximately 1.5 liters per minute. However, if

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11/45 will make it apparent to a person skilled in the art, aware of the state of the art, that other flow rates may be used depending on the model of the ozone generator 22 and the size of the sterilization chamber.

The vacuum in the sterilization chamber 10 is produced by means of the vacuum pump 40 and the drain valve of the sterilization chamber 44.

Valves 20a and 29b are Teflon solenoid valves (CM-900-156, TSO ₃ Inc.), Valve 25 and vacuum valve 44 are solenoid valves (CM-015004, TSO ₃ Inc.).

The preferred ozone generator used in the process and apparatus of this invention is a corona discharge type generator, which is well known in the art and does not need to be described here.

A preferred method of sterilization according to this invention includes the following general steps as illustrated by the flow chart of Figure 3. Items to be sterilized, such as medical instruments, may be placed directly in the sterilization chamber, but will preferably be sealed in sterile packaging containers , sterile packaging, or pouches as generally used in the hospital environment and then placed in the sterilization chamber. Various different types of said containers or pouches are well known in the art and need not be described herein.

After the insertion of the article to be sterilized has been made in the sterilization chamber in step 320, the sterilization chamber door is closed and the chamber sealed in step 340 and a vacuum being applied to the sterilization chamber in step 350 until a first pressure 1 Torr (1.33 mbar) is reached in the chamber. The walls of the sterilization chamber have preferably been preheated in a heating step 310 to a temperature of 40 ° C. The evaporated hydrogen peroxide solution is admitted to the sterilization chamber in the 360 moistening step to partially sterilize and moisten the camera contents. The injection of

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12/45 evaporated hydrogen peroxide solution is stopped once a 19 Torr pressure increase has been achieved in the chamber. The chamber can be kept sealed for a first exposure period 370 (preferably 2 minutes) during which the hydrogen peroxide at least partially decomposes to free radicals, water and oxygen. Preferably, this exposure period can also be omitted. An ozone-containing gas, preferably in the form of a mixture of dry ozone and oxygen, is then supplied to the chamber at the ozone injection step 380 and the chamber kept sealed for a second pre-selected exposure period 390. No wetting of the ozone-containing gas it occurs, or is even necessary, once the atmosphere of the chamber has been moistened by the hydrogen peroxide solution. Between the application of the vacuum, before the hydrogen peroxide evaporation step, and the end of the second exposure period, any removal of any components from the sterilization atmosphere will be stopped so that none of the components of the atmosphere are removed before the end of the second exposure period. The vacuum application steps, injection of hydrogen peroxide with first exposure period and injection of ozone gas with second exposure period, are preferably repeated at least once, the number of repetitions being determined in step 395 based on the cycle previously chosen in step 330. To remove any remaining sterilizer from the sterilization chamber 10 after the sterilization cycle is completed a ventilation phase 400 is initiated, which preferably includes multiple cycles of evacuation from the chamber and flowing with oxygen. After ventilation 400, the door is unlocked in step 410 and sterile articles can be removed from the chamber. The temperature of the floor and door of the chamber and the evaporator unit will preferably be controlled through the sterilization process.

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In an exemplary sterilization device according to this invention, the user has a choice of multiple different sterilization cycles. In a preferred method, the user will be able to choose in the cycle selection step 330 of the process between three cycles that have the respective characteristics shown in Table 1 and discussed below.

Table I

Cycle phases Cycle 1 Cycle 2 Cycle 3 Vacuum 1 Torr 1 Torr 1 Torr Wetting with 50% solution H202 20 Torr 20 Torr 20 Torr Wetting plateau (optional) 2 min 2 min 2 min 03 Injection 2 mg / L 10 mg / L 3 mg / L Exposure 5 min 5 min 10 min Number of repetitions 2 2 4 Approximate cycle duration 46 min 56 min. 100 min.

[0013] Cycle 1 - Sterilization of device surfaces having low ozone compatibility, articulated devices and endoscopes with short flexibility (1 mm x 85 cm). (Eg chambers, cables, shovels, forceps, bronchoscopes, uretoscopes).

[0014] Cycle 2 - Device surfaces with high ozone compatibility, articulated instruments and rigid endoscopes (Imm x 50 cm).

[0015] Cycle 3 - Sterile instruments with cycle # 1 and complex endoscopes (eg gastrocopes, colonoscopes).

[0016] Although it is preferred to operate the present sterilization process using 50% hydrogen peroxide solution, the process can be operated with solutions including 3% - 50% hydrogen peroxide. Exemplary conditions for the process when operated with a 3% - 30% and 50% hydrogen peroxide solution are as follows:

Table II

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% H2O2 Maximum pressure injection (Torr) Dose of ozone (mg / L) Number of repetitions Time to conditioning 3 44-54 25-50 2-8 2 hrs. 30 30-44 5-25 2-6 2 hrs. 50 17-21 (20) 2-10 2-4 0 hr

[0017] The maximum injection pressure is the pressure at which the injection of the evaporated hydrogen peroxide solution is stopped. The conditioning time represents a period of time after sealing the chamber and before applying the vacuum in which the articles to be sterilized are kept in the sterilization chamber and gradually heated from room temperature due to the chamber walls, floor and door being heated to approximately 40 ° C. This heating of the charge in the chamber is required to prevent undue condensation of water in the charge in the injection of the evaporated hydrogen peroxide solution. The risk of condensation increases with decreasing concentrations of hydrogen peroxide solution.

[0018] Once the user has chosen one of the three cycles, the user closes the sterilization chamber door and presses the start button. The sterilizer control system (see Figure 9) then, under the control of the construction of an operational software, starts the sterilization process according to the chosen cycle and using pre-selected parameters for the chosen cycle. There is no preconditioning of the sterilization charge. The cycle begins with the generation of a vacuum in the sterilization chamber of approximately 1 Torr (1.33mbar). A solution of evaporated aqueous hydrogen peroxide is subsequently injected into the chamber through the evaporator unit to partially sterilize and moisten the charge. Before entering the evaporator unit, the hydrogen peroxide solution passes through the measurement unit 240 shown in Figure 8.

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The measurement unit 240 is directly connected to the evaporator unit 260 and then subjected to the vacuum pressure present in the chamber. The measurement unit 240 is directly connected to the evaporator unit 260 and then subjected to a vacuum pressure present in the chamber. The measuring unit 240 includes a base block 241 having a passage of a known volume fixed (not shown) and connected by an inlet valve 242 at an upper end of the passage to the hydrogen peroxide reservoir 220 and by a pressure valve. exhaust 243 at a lower end of the passage of the evaporator unit 260. The flow of the hydrogen peroxide solution through the measurement unit 240 can be exactly controlled by means of valves 242, 243, which are switched opposite and not overlapping so that one valve will always be closed when the other is open and both valves will never open at the same time. In this way, the passage is evacuated when the exhaust valve 243 is opened and the inlet valve 242 is closed, filled with hydrogen peroxide solution when the exhaust valve 243 is closed and the inlet valve 242 is opened and evacuated. again when exhaust valve 243 is open again and inlet valve 242 closed again. Once the exact passage volume is known, the amount of the hydrogen peroxide solution supplied per valve cycle will be known and the total amount of hydrogen peroxide can be calculated based on the number of valve switching cycles. The number of times and the frequency that valves 242, 243 open and close is controlled and monitored by a software device and can be used to determine the amount of hydrogen peroxide solution removed from the reservoir and to theoretically calculate the remaining amount of the solution in the reservoir, based on the total amount drawn from the supply bottle and the measured quantity. The inventors of the present apparatus and method have

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16/45 discovered that, contrary to the general knowledge of the exact amount of evaporated hydrogen peroxide supplied in the chamber is not critical. In contrast, the inventors of the present application have surprisingly found that the most reliable determinant of the effectiveness of sterilization of hydrogen peroxide vapor is the pressure in the chamber. The effectiveness of sterilization is dependent on the saturation level of the sterilization atmosphere with hydrogen peroxide.

[0019] However, the saturation level cannot be reliably calculated from the quantity of the injected solution, since it depends a lot on the load in the chamber and the adsorption characteristics of the materials in the load. The saturation level is, however, directly proportional to the pressure in the chamber. Therefore, the saturation level in the chamber can be determined solely on the basis of the chamber pressure a little more than by measuring the flow or quantity of the hydrogen peroxide solution injected into the chamber. As a result, the number of cycles switching the valves during the hydrogen peroxide injection step 360 in a configuration of the present invention is totally dependent on the pressure to be achieved in the chamber 10 in addition to the hydrogen peroxide injection. In a preferred configuration, 50% of a hydrogen peroxide solution is used and the pressure increases to be reached in the chamber being 19 Torr. An optional interruption time of 2 minutes follows the pre-set pressure increase of 19 Torr. Then, a dose of gas containing dry ozone is injected followed by a second exposure time. The ozone dose depends on the cycle chosen by the user. When the desired number of repetitions of the first and second stages of partial sterilization is reached, the ventilation of the sterilization chamber 10 is prepared by evacuating and refilling the chamber 3 times with oxygen in order to remove residues of hydrogen peroxide and sterilizers from ozone.

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17/45 [0020] In order to determine if a variation in the volume of hydrogen peroxide injected by each pulse during the conditioning phase having an efficiency impact on sterilization and the amount of condensation observed in the load, to the applicant performing the sterilization testing with different amounts of injection pulses. Theoretically, the speed of injection / evaporation of hydrogen peroxide could have an impact on the effectiveness of sterilization. By injecting a much larger volume during each pulse, the solution is pressed more quickly into the chamber, and the time for the liquid to evaporate is reduced. The chance of having more condensation on the instrument or on the packaging material is thus greater. Condensation that is very pronounced would be expected to create two problems. First, pronounced condensation may limit the ability of ozone to reach spores on the surface of instruments. Second, the hydrogen peroxide liquid may remain trapped in the packaging material, being dangerous for people who handle the sterilized cargo afterwards. If the amount of hydrogen peroxide liquid trapped is too large, the ventilation of the chamber and the packaging at the end of the sterilization cycle may not be sufficient to remove all evidence of condensed hydrogen peroxide.

[0021] When the pressure in the sterilization chamber is decreased below atmospheric pressure, any liquid present or injected into the chamber will be boiled at a temperature lower than atmospheric conditions. In the above-described configuration of the present process, the pressure in the chamber is first reduced and then a volume of hydrogen peroxide being injected as a vapor. The total volume of the hydrogen peroxide used is injected into small excreta. During the injection, the pressure in the chamber increases until a final pressure of 20 Torr (1 Torr starting the pressure + 19 Torr of pressure increase) is reached. Peroxide

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18/45 hydrogen evaporates at a higher temperature than water (50% of the boiling point of hydrogen peroxide being 114 ° C, and the boiling point of water being 100 ° C). Thus, the condensate will be more concentrated in the hydrogen peroxide than in the initial solution entering the chamber. This phenomenon was observed with a UV lamp placed in the chamber. Even if the pressure in the chamber was increased, the concentration of hydrogen peroxide in the vapor read by a UV lamp decreased. Also, the concentration of a first dripped hydrogen peroxide (10 Torr) was titrated. It was understood that the liquid was approximately 85% concentrated hydrogen peroxide. However, condensation of hydrogen peroxide interferes with the sterilization of long lumens when hydrogen peroxide is removed from a vapor phase during condensation. Thus, in order for hydrogen peroxide to penetrate long lumens, hydrogen peroxide should be kept in the vapor phase as much as possible and condensation avoided during the injection of hydrogen peroxide.

[0022] At a pressure of approximately 10 Torr, a microcondensation layer of hydrogen peroxide appeared on the objects in the chamber. The thickness of the micro-condensation has been calculated to be only of small dense molecules, but can assist in sterilization, since it is well known that hydrogen peroxide can sterilize in the form of steam, as well as in liquid form (Chung et al., 2006; UngerBimczol et al., 2008). In addition, ozone is more soluble in hydrogen peroxide and may form straight radicals on the surface, where spores are present.

[0023] In order to inject a high volume at once, a valve separated by the Teflon tubing was used instead of the normally used micro-valve (AM-213-001, TSO3 Inc.,). The size of the tubing was determined by the volume to be injected. Once the volume contained in the

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19/45 valve is significant, two valve sizes were used. The first type (TSO3 #: CM-900-157) with a 0.062 ”orifice, was used for a volume of up to 1.5 mL. The second type Neptune, with a 0.156 ”orifice, (CM-900-156, TSO3 Inc.), was used for a volume of up to 3.5 mL. The larger valve size also helps to pressure the large volume of liquid in the chamber. For the volume of 35 pL, a Burket 7616 micro-pump (CM-113001, TSO3 Inc.) was used. For a volume of 23 pL, a larger, specially made block was used.

[0024] Two cycles were used for this experiment. The sterility test, Cycle 1 (half-cycle) was used, where the injection stage of the conditioning phase was modified with a variation in volume and pulse for each attempt, as previously described. As for the condensation effect, Cycle 3, consisting of four phases, was used. This cycle was chosen due to the fact that a greater amount of hydrogen peroxide was injected into the cycle, making the case scenario worse. A third test was performed for the sterility test. Lumens (Teflon 1 mm x 80 cm) were inoculated using the wire technique according to MCB-09A07. After exposure of a half cycle of Cycle 1, the sterility of each lumen was determined according to MCB-09-A04 rev. 7 for quantitative recovery using ultrasound technique followed by filtration.

[0025] A burette was connected to the valve system to precisely determine the volume injected. The volume was then divided by the number of pulses. The three TSO3 cycles were tested with a special load representing an average load for these three cycles. The load was always at room temperature at the beginning of the cycle. A UV lamp was also installed in the used sterilizer. This allowed analysis of hydrogen peroxide vapor during the conditioning phase.

[0026] Sterility was checked with Teflon wires (1 mm x 80 cm) inserted in the tubing, and tested in a half cycle of Cycle 1. The first

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20/45 volume injected by each pulse during the conditioning phase was 1.5 mL. In case of a good result for sterile efficiency, the volume can be doubled. If the result is not satisfactory, then half the volume would be tested. Since the test result using 1.5 mL per pulse was good, the test was repeated with 2.5 mL and 3.4 mL. The test was halted at the injection of 3.4 mL since only two pulses were needed to achieve the desired pressure of 18 Torr. The normal conditioning phase was stopped at 19 Torr, but to ensure the pressure was not exceeded, the micro-valve was used between 18 to 19 Torr.

[0027] Sterility was achieved with 3.4 mL (all tests were zero for spore count). Thus, the applicant found that variations in pulse volume had no effect on the effectiveness of sterilization. However, it was reported during the sterility test that condensation was present exactly where the hydrogen peroxide was injected into the chamber. Thus, further tests were carried out to determine the maximum volume that could be injected for each pulse without condensation. [0028] The first injected volume was again 1.5 mL. Condensation was present in the injection site load. The amount of condensed liquid measured was similar to that observed with an injection pulse of 3.4 mL. The number of pulses was then gradually decreased by reducing the amount injected each half time until no more condensation was visible. At 75 pL, the condensation was again similar to that with an injection pulse of 3.4 mL. A significant reduction in the construction of condensation was observed below a pulse volume of 75 pL. Condensation 35 pL is still visible but very low. At 23 pL, almost no condensation was visible. At a pulse volume of 16 pL absolutely no condensation was observed. Condensation was found for pulse volumes above 20 pL. So, to control the amount of unwanted condensation of hydrogen peroxide, it will be

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21/45 it is preferable to use a pulse injection volume less than 75 μΙ_, more preferably below 35 μΙ_, more preferably approximately 20 μΙ_.

[0029] In an exemplary process according to this invention, the walls of the sterilization chamber are maintained at a temperature of 40 ° C, while the temperature of the charge can vary between 20 ° C and 25 ° C. The concentration of the hydrogen peroxide used will preferably be 50%, but concentrations below 3% and above 59% may be used. The pressure reached inside the chamber is a function of the concentration of hydrogen peroxide used (see Table II). Although the pressure reached is the same for each cycle discussed above, the volume of the hydrogen peroxide solution required depends on the concentration of the solution, the type of charge in the chamber and the adsorption capacity of hydrogen peroxide in the charge. The level of moistening in the sterilization atmosphere before ozone injection can be adjusted by using different concentrations of the hydrogen peroxide solution.

[0030] The ozone dose varies between 2 mg / l for cycle # 1 and 10 mg / l for cycle # 2 and its exposure time varies between 5 minutes for cycle # 1 and 10 minutes for cycle # 3 .

[0031] The amounts of ozone used in the sterilization processes known in the art using ozone moistened as a sterilization gas are generally approximately 85 mg / l. Using hydrogen peroxide for partial sterilization as well as wetting the load before ozone injection allows a significant reduction in the amount of ozone required to achieve sterilization (SAL 10 ' ⁶ ) below a dose between 2 mg / l and 10 mg / l , depending on the chosen cycle. This reduction is much greater than that expected because the

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22/45 hydrogen peroxide and ozone are used in the same sterilization cycle.

[0032] In fact, the evaporated hydrogen peroxide solution injected into the chamber is not enough to achieve sterilization, despite a reduction of 4 log. in the spores have been observed. However, adding only a much smaller amount of ozone in the range of 1-10 mg of ozone per liter of the sterilization atmosphere results in complete and total sterilization at the level required under FDA Safety Guarantee Level standards or worldwide standards, such as ISO (SAL 10 ' ⁶ ). Such complete sterilization cannot be achieved using only the injection of the evaporated hydrogen peroxide solution, regardless of the amount of hydrogen peroxide solution used and the concentration of the solution. In addition, high concentrations of hydrogen peroxide reduce the compatibility of some instruments. In addition, a longer time after the injection of hydrogen peroxide, for example, 3 minutes instead of 2 minutes, does not accentuate the effectiveness of sterilization. In fact, the time that elapses after the injection of hydrogen peroxide appears to have no effect on the effectiveness of sterilization. So, just adding the least amount of ozone as discussed above surprisingly leads to complete sterilization.

[0033] During and evacuation step 350 (see Figure 3), the oxygen supply valves 21 and 26, the mixture supply valve 29a, and the mixture bypass valve 29b are closed and the chamber drain valve 44 being opened. The sterilization chamber 10 is evacuated at a vacuum pressure of approximately 1 Torr (1.33 mbar). Once this pressure is reached, which is determined by means of a pressure sensor 13 in the sterilization chamber, the drain valve of chamber 44 is closed and the measurement unit 240 is activated to supply the hydrogen peroxide solution in the evaporator unit 260 in which the solution is

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23/45 evaporated and subsequently flows freely into the sterilization chamber 10. Once the pressure of 19Torr in the sterilization chamber 10 has been reached as determined by means of a pressure sensor 13, the measuring unit 240 is deactivated and the supply of the hydrogen peroxide solution to the evaporator 260 is stopped. The chamber can be kept sealed so that no injection of any substance occurs during the next first exposure period 370, which can last for 2 minutes. However, this exposure period is completely optional. Shortly before the end of the 360 hydrogen peroxide injection step (usually approximately 2 to 6 min.) The ozone generator is activated to ensure the supply of the ozone-containing gas. The flow of the mixture / oxygen / ozone leaving the ozone generator is controlled at all times by the regulating orifice 28 capable of resisting the vacuum and adjusting the flow between 1 and 3 liters per minute. Activation of the ozone generator 22 includes opening the supply valve 26 and the mix bypass valve 29b. The supply valve 26 allows oxygen to enter the generator. The oxygen / ozone mixture produced by the generator is then guided directly on the ozone catalyst 52 through the mixture bypass valve 29b. After the completion of step 370, the oxygen / ozone mixture produced by the generator 22 is guided in the sterilization chamber 10 by opening the mixture supply valve 29a and closing the mixture bypass valve 29b. The oxygen / ozone mixture enters chamber 10 until the desired concentration of ozone according to the chosen cycle is reached in the chamber. The time required for this step is dependent on the flow rate and concentration of the ozone gas in the mixture (preferably from 160 to 200 mg / l NTP), as determined by the ozone monitor 15 of a type well known in the art. Once the desired concentration is reached, the mixture supply valve 29a is closed to seal the

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24/45 sterilization chamber and keep the oxygen / ozone gas mixture in the chamber under vacuum.

[0034] Once the supply of the sterilization gas (mixture of oxygen and ozone gas) in the chamber is paralyzed, the generator 22 is paralyzed and the oxygen supply valve 26 is closed. The chamber is kept sealed for an exposure period of 5 to 10 minutes, depending on the sterilization cycle chosen by the user. Still dependent on the chosen cycle, steps 350 to 390 are repeated 1 to 3 times before sterilization is completed. This arrangement is in accordance with the standards of the Security Level of 10 ' ⁶ (SAL 10' ⁶ ).

[0035] To remove all remaining hydrogen peroxide, ozone and moisture in the sterilization chamber 10 after complete sterilization, the ventilation phase 400 is engaged. The ventilation phase begins after the last exposure period 390. The drain valve of chamber 44 is opened and a vacuum is applied for approximately 6.5 mbar. Once the vacuum pressure of 6.5 mbar is obtained, the drain valve 44 closes and the oxygen supply valve 21 opens, accepting oxygen in the sterilization chamber 10. Once the atmospheric pressure is reached, the supply valve of oxygen 21 is closed, the drain valve of chamber 44 is opened, and a vacuum reapplied until a pressure of 1.3 mbar is reached. This last ventilation cycle, below 1.3 mbar, is repeated once more for a total of three ventilation cycles. Once atmospheric pressure is reached after the last cycle, the sterilization chamber door mechanism is activated in step 410 to allow access to the contents of the sterilization chamber. The ventilation phase has two functions. Firstly to remove all sterilizing residues in the sterilization chamber before opening the access door, and secondly, drying the sterilized material by evaporation when vacuum pressure is applied. Evidently, different vacuum pressures,

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25/45 cycle time and number of repetitions can be used, as long as a desired sterilizer removal and drying is achieved.

[0036] Sterilizers and moisture, containing gas evacuated from sterilization chamber 10, pass through catalyst 52 before exhausting the gas in the atmosphere to ensure a complete decomposition of the sterilizers. Catalyst 52 is used during only two parts of the sterilization cycle, the activation of generator 22 (with valves 26 and 29b) and the evacuation of sterilization chamber 10. During the beginning of the generator 22 phase, the bypass valve of the Mixture 29b is opened and ozone is guided through catalyst 52. Once the start of the generator phase is completed, bypass valve 29b closes. During ventilation of the sterilization chamber 10, the drain valve of the sterilization chamber 44 is opened and the ozone containing the residual sterilization gas is guided to catalyst 52. Once the evacuation of the sterilization chamber is completed, the drain valve 44 is closed.

[0037] Ozone circulation is ensured by the vacuum pump 40. Catalyst 52 can be positioned above or below the vacuum pump 40.

[0038] In effect, at 20 ° C, water boils at an absolute pressure of 23.3 mbar and at 35 ° C, water boiling at an absolute pressure of 56.3 mbar. The vacuum in the sterilization chamber is preferably adjusted to a pressure where the boiling temperature of the water is lowered below the temperature in the sterilization chamber. The boiling temperature can be so low that the temperature of the hydrogen peroxide solution in the evaporator unit decreases rapidly and, depending on the viable energy of the surrounding structure, it can freeze if no energy is supplied. The energy needed to evaporate the hydrogen peroxide solution is taken from many sources. It is mainly taken from the main body of the evaporator unit 260, which in the form of a block of

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26/45 aluminum fitted with a heating matching (not shown). The evaporation process can also cool the humidifier to a point where moisture condenses on the walls of the sterilization chamber. This is avoided by heating the chamber walls to keep them at least at room temperature, preferably at 40 ° C. This is achieved with a heating arrangement (not shown) that will be apparent to a person skilled in the art, aware of the state of the technical.

[0039] The evaporated hydrogen peroxide solution injected into the chamber increases the relative humidity in the sterilization chamber. This moistening significantly improves the effectiveness of the ozone sterilization step. The sterilization gas containing oxygen / ozone is injected into the sterilization chamber moistened at a temperature close to the environment. The ozone-containing gas is not heated before injection.

[0040] Hydrogen peroxide has its limitations when it sterilizes medical instruments. H2O2 is less stable when in contact with metal, such as stainless steel. This problem is compounded at low pressures, in which chemical reactions are accelerated. Thus, the decomposition of hydrogen peroxide will be accelerated under vacuum, limiting the viable time to sterilize large metal tubing. In addition, the diffusion of H2O2 is limited since it is not a gas. The hydrogen peroxide would reach the end of the long pipe by means of diffusion, but by the time of its concentration it will have decreased, due to the accelerated decomposition to a level where it will no longer be sufficient for sterilization.

[0041] The applicants found, as shown above, that these problems cannot be overcome by adding a sterilizing gas such as ozone, but moistening the chamber by decomposing hydrogen peroxide in free radicals improves the effectiveness of the sterilizing gas. In addition, applicants surprisingly discovered

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27/45 that ozone can be advantageously substituted by nitrogen monoxide or nitric oxide. Applicants found that the water and oxygen generated during the decomposition of hydrogen peroxide also improves the effectiveness of nitric oxide.

[0042] Nitrogen monoxide (or nitric oxide) is known to be a toxic cell at low concentrations. In the presence of water and oxygen, NO reacts to form nitrogen dioxide, NO2, which is also highly toxic. In the absence of oxygen, NO does not form NO2, but reacts to form nitric acid, which is very corrosive to other materials.

2NO + 3H2O2 -> 2HNO3 + 2H2O (1)

2NO2 + H2O2 -> 2HNO3 (2) [0043] The problem of nitric acid formation is minimized by mixing nitric oxide with hydrogen peroxide instead of water, since the required concentration of NO after peroxide preconditioning hydrogen is very low. H2O2 treatment weakens the spore layer, and hydrogen peroxide and nitric oxide when mixed together, forming free radicals, similar to the reaction of ozone when mixed with hydrogen peroxide.

HO + H2O2 -> H2O + HO2. (3) HO2. + NO -> HO. + NO2 (4) HO. + NO -> HONO (5)

[0044] These radicals will react quickly with organic substances, oxidizing them. The oxidation speed will be in the order of 109, instead of 101 for NO or 03 alone.

[0045] Applicants have tested the effectiveness of replacing the ozone gas originally tested with another gas, such as oxygen and nitric oxide. The test assessed the sterile effectiveness of the inoculated devices. Inoculated wires were inserted into the tubing and then into pouches. The pouches were also

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28/45 placed on top of the cargo transport in the sterilization chamber. This area is considered the least effective point in the chamber.

[0046] Examples:

[0047] The same charges were used for the three series of tests carried out: ozone, oxygen and nitric oxide. The length, diameter, material and type of tubing were different for each cycle and are described in Table 3. The inoculated lumens were placed in a special load representing an average load for the three cycles.

Table 3: Pipe length, diameter and material for each cycle.

Number of cycles Diameter (mm) Length (cm) Material Cycle 1 1 80 Teflon Cycle 2 1 50 Stainless steel Cycle 3 1 110 Teflon

[0048] The lumens used to assess sterile efficacy were inoculated according to protocol MCB-09-A07 rev. 9. The yarn method was used. The yarns were inoculated with 10 μΙ_ of a suspension of spores G. estearotermofilus ATCC 7953 from 1.0x10 ⁶ to 2.5 x 10 ⁶ UFC / 10pL. The inoculated strands were left to dry overnight under normal temperature conditions.

[0049] The tested loads were exposed to a half-cycle for each cycle. For the experiment with oxygen and nitrogen oxide, ozone was replaced by the gas to be tested. A burette was also connected to the valve system in order to precisely determine the volume of H2O2 injected. After exposure, the sterility of each lumen was determined according to MCB-09-A04 rev. 7 for quantitative recovery using ultrasound technique followed by filtration.

[0050] Ozone

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29/45 [0051] The baseline of the sterile efficacy of the inoculated lumens used in each cycle was established using only hydrogen peroxide. Cycles using hydrogen peroxide and ozone were performed to compare the effectiveness of oxygen and nitrogen oxide for ozone.

[0052] Oxygen [0053] Oxygen was injected into the chamber using the same system as that used for ozone. The ozone generator has been turned off.

[0054] Nitric oxide [0055] The NO was meanwhile injected directly into the chamber from an independent NO cylinder (Praxair). A Neptune valve with a 0.156 ”orifice (CM-900-156, TSO3 Inc.) separated by a Teflon tube was used for this injection. Thus, the gas was forced into the chamber.

[0056] All tests were carried out abroad in order to limit possible additional leakage hazards. A NO detector was used. A long tube was connected to the converter unit of the catalyst, to allow NO to be eliminated from the arrangement. A calculation was performed (see below) to determine the number of valve injections required to obtain a concentration of 2 mg / L.

Valve volume: 3.3 mL (Volume calculated in R-1937)

NO DTP density: 1.25g / l Sterilization chamber volume: 125 L Final desired concentration: 2mg / L NO pressure: 3 psig

Corrected volume: 3300 x ((14.7 + 3) /14.7) = 3973.2 pL

Mass to be injected: 0.002 g / L x 125L = 0.25gno

Injected mass for each injection: 1.25g / L x 0.003974L = 4.9665 X

10-3 g / injection

Number of injections required: 0.25gno / 4.9665 X 10-3g / injection = 50 injections

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30/45 [0057] Two lenses were present in the camera, one at the bottom rear, and the other at the top top. They were exactly aligned on top of each other. One lens emitting UV light from a tungsten source, and the other lens being connected to a UV detector. This arrangement allowed the measurement of hydrogen peroxide vapor in the chamber.

[0058] Hydrogen peroxide has some activity of inactivation against spores of G. estearotermofilus. However, the percentage of sterility achieved in lumens is not sufficient to use it alone, especially for long, rigid flexible lumens. The results for hydrogen peroxide and other gases mixed with hydrogen peroxide are summarized in Table 4.

Table 4. Percentage of sterility for three cycles TSO3 with different sterilizing agent mixed with hydrogen peroxide.

Used sterilizing agent Sterile Lumens Cycle 1 Cycle 2 Cycle 3 H2O2 50% 12.5% 16% H ₂ O ₂ + O3 77% 50% 77% H ₂ O ₂ + O ₂ 11% 0% 77% H ₂ O ₂ + NO 100% 66% 66%

[0059] In the case of oxygen mixed with hydrogen peroxide, concentrations equivalent to the ozone dose were used in each cycle, in other words, 2 mg O2 / L for 0 cycle 1, 10 mg / L for 0 cycle 2, and finally 3 mg / L for 0 cycle 3. Oxygen impaired the efficiency of the process in Cycles 1 and 2 compared to hydrogen peroxide alone or mixed with ozone. In cycle 3, the efficiency of the process with oxygen or ozone is equivalent. Consequently, oxygen was found to be ineffective to replace ozone.

[0060] Although nitric oxide is well known as a disinfectant, it has never been mixed with hydrogen peroxide, since the mixture

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31/45 may be explosive in high concentrations. To minimize the danger of explosion, the NO concentration was limited to 2 mg / L for three cycles of a first series of tests. Sterility has been achieved for some samples in all cycles so that the concentration of nitrogen monoxide has not yet been increased. The results were very conclusive, ie better than or similar to ozone mixed with hydrogen peroxide.

[0061] Even if no control is done to verify the inactivation of G. estearotermofilus spores by NO in this study, it has been demonstrated in multiple studies that the rate of NO inactivation is low. When NO is injected into a sterilization chamber and combined with air humidity, NO reacts with oxygen at a predictable rate to form NO2, which is lethal to the spores of G. estearotermofilus. When NO is injected into a sterilization chamber without any oxygen atoms present, NO does not form NO2, and the spores are not sterilized (http://www.mddionline.com/article/sterilizinq-combination-products-usinq- oxides -nitroqen). Based on data from the publication of the Noxilizer sterilization process, at 5.12 mg / L NO2, the D-value will only be 0.3 minutes. At 3 mg / L, the D value is approximately 1.9 minutes.

[0062] In this experiment, the amount of NO injected was 2 mg / L. Considering that all NO molecules were transformed into NO2, a D-value of 1.9 minutes for the concentration of 2 mg / L of NO2, only 1.5 log. spore would have been activated by NO2. This is less than 6 log. inoculated devices. In reality, the conversion rate from NO to NO2 will probably not be 100% and the D-value will be more than

1.9 minutes, so the number of spores inactivated by NO will only be around 1 log.

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32/45 [0063] The substitution of ozone with another gas was tested in all three cycles of the present process. The injection of hydrogen peroxide was performed as usual.

[0064] Two gases were tested. The first, oxygen, did not reach conclusive results. Sterility was not achieved in two of the three cycles.

[0065] Nitric oxide was also tested. The results showed complete sterility in all three cycles. The concentration used for all tests was low. Only 2 mg / L was injected for three tests. The use of this chemical could be considered in the future. However, significant changes to the sterilizer had to be made to accommodate this. Since NO2 is formed during cycles, only compatible materials can be used. In addition, protective equipment such as a NO detector could have been considered.

[0066] Other sterilizing gases that may interact with hydrogen peroxide to continue the formation of free radicals may be used instead of ozone, such as dioxide chloride.

[0067] On the other hand, many different molecules may have the same effect as hydrogen peroxide in ozone. Some ions may also have a catalytic effect of hydrogen peroxide on ozone. CO ² , Ni ²⁺ , Cu ²⁺ , Mn ²⁺ , Zn ²⁺ , Cr ²⁺ and Fe ²⁺ , Ti ²⁺ ions accentuate ozone decomposition (Ahmed et al., 2005). All transition metals that can form a molecule with oxygen will decompose 0 ozone. Positive ions will try to become neutral by carrying an oxygen atom to the ozone molecule. The ozone molecule being more or less stable will easily give the oxygen atom. Water with a basic pH will be richer in hydroxyl ions. hydroxyl ions decompose 0 ozone into atomic oxygen. Those oxygen atoms may later form hydroxyl radicals. So, any molecules that can be used to serve the pH solution

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Basic 33/45 will favor ozone decomposition. Good examples are NaOH or KOH.

[0068] Another source of hydroxyl radicals are all solvents containing an alcohol group. These solvents provide OH ions and favor ozone dilution. In the same trend, humic and formatted substances may initiate the radical formation of chains (Glaze et al., 1987). Some acids may also be used as acetic acid and para-acetic acid. Ozone being more soluble and stable in acidic solution will be able to react for longer and more concentrated. Any molecule containing a carbonate, bromide, phosphate or sulfate group will also decompose ozone. (Beltrán, 2004).

[0069] As shown in Figures 2 and 7, the dispensing unit 200 includes a bottle retainer 202 for receiving a sealed hydrogen peroxide solution bottle 180. The bottle retainer has a bottle seat 204 in which the bottle 180 is fixedly received. Bottle 180, which will be discussed in more detail below, is held in seat 205 by gravity only. Bottle retainer 202 is pivotally mounted to pivot 203 for movement between an open position as shown in Figure 7, in which bottle 180 can be placed or removed from the bottle retainer and a closed position in which the bottle retainer is completely inside the sterilizing cabin (not shown) and a front cap 205 of the bottle retainer closing all access of the bottle retainer outside the cabin. When retainer 202 is in the closed position, a pneumatically directed drain arrangement 207, including a steering needle, in this configuration a vertically oriented pneumatic cylinder 208, and a drain needle 209 mounted on the piston rod 210 of the cylinder, being activated to drain a solution of hydrogen peroxide from bottle 180. This is achieved by activating cylinder 208 to force needle 209 through the sealed bottle to the tip

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34/45 of the needle reaches the bottom of the bottle 180. The needle 209 is fluidly connected to the reservoir 240 (see Figure 8) and the solution being aspirated from the bottle 180 in the reservoir 240 by using a vacuum generated by a vacuum pump 44 for reservoir 240 and can be fluidly connected via conduit 211 and valve 212 (see Figure 1). Once the contents of bottle 180 have been aspirated, the retainer can be opened and the bottle removed, or the empty bottle can be kept in the retainer until a refill of reservoir 240 is required. The reservoir 240 is provided with a level sensor 242 that provides a signal to the control system at the liquid level of the reservoir. Based on the signal received from sensor 242, the control system notifies the user if the amount of liquid in reservoir 240 is insufficient for the execution of the cycle selected by the user.

[0070] In an alternative configuration, the hydrogen peroxide distribution system does not include a reservoir. Instead, bottle 180 is properly cooled (CS-01) to prevent rapid degradation of aqueous hydrogen peroxide. A sensor (S14) measures the amount of solution left in the bottle. When the solution reaches a 1st selected level, a first signal appears on the screen and when a 2nd pre-selected level is reached, the message generated from the software to the operator specifies that only one more sterilization of cycle # 1 or cycle # 2 can followed with the remaining solution in the bottle. The operator will then have to refill the dispensing system with a new full bottle.

[0071] As shown in Figures 10a to 10d, bottle 180 has a tapered bottom 182 to ensure complete drainage of all liquid in the bottle, thus reducing the risk of spillage or contamination when removing a drained bottle. In order to ensure that the bottle 180 remains securely upright, a support 184 is attached to the lower end of the bottle. Support 184 includes an upturned canopy

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35/45

185 fixed in a circumferential groove 186 in the outer wall of the bottle 187. The needle 209 is aligned with the lower end at the bottom of the bottle and can be moved in the bottle, through the sealed bottle, until it reaches the lowest point in the bottle . Electronic or mechanical control structures and functions are provided to ensure contact of the needle with the bottom of the bottle while preventing penetration of the bottom of the bottle. A pressure sensor is preferably incorporated into the reciprocal targeting needle and / or the mounting needle (not shown).

[0072] Control system [0073] The sterilization device is preferably controlled by a scheme shown in the electrical block diagram (Figure 9 and Process Flow Diagram (Fig. 3). The control system is built around a PLC (Programmable Logic Controller) shelf This shelf contains a power supply (107), a CPU unit (108), a Transceiver Network Device (109), a discrete DC Volt 32 x 24 input module (110), a module 16 x 120VAC discrete output module (111) and finally a transistor discrete output module (112), an RS232C communication module, all of which are stacked together by an intrinsic connection system that contains a data bus and addresses. [0074 ] The network device (Net) is a serial communication protocol widely used in the industry for instrumentation and control. In this sterilization device the Transceiver Network Device (109) is used to communicate in full duplex, the data between the CP U (109) and the 15 bit A / D converter (106), a 15 bit D / A converter (125) and both Digital Temperature Interfaces (120), (121).

[0075] The PLC CPU has three RS232 ports. One is used to receive and send data to the Touch Screen Terminal (118), another is used to send data to a thermal printer (119) and the last port is used

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36/45 as a service port where a PC (Personal Computer) can be connected to communicate with the PLC CPU (108) to load the control protocol program (the Control Protocol Program is not in the scope of this document).

[0076] The Touch Screen terminal (118) is positioned in front of the sterilizer next to the thermal printer (119). The Touch Screen terminal and the thermal printer constitute a User Interface terminal. [0077] Energy required for: thermal printer (119), Network Link Device (109), (106), (120) (121), (125); Chamber Pressure Sensor (104), electric oxygen regulator (126) and PLC discrete input (11) and discrete outputs (112) being provided by the DC Power Supply (103).

[0078] The Chamber Pressure Sensor (104) and the Ozone Monitor (105) have an output signal pattern from 0 to 10VDC. The Electronic Oxygen Regulator has an output of 0 to 5 VDC. All signals are sent to the 15-bit A / D converter. All converted signals are sent to the CPU by the digitally connected Network Device for processing.

[0079] The energy input (100) of the sterilizer is a 208 to 240 VAC triple wire of the single phase type without neutral. The energy input is filtered to prevent conducted RFI (101). The energy is distributed by the energy distribution bus (102) to various electrical systems of the sterilizer device.

[0080] A cooling system (60) is used to cool the ozone generator. This system includes the cooling unit (114) and the circulating refrigerant pump (113). The refrigerant temperature in the generator is sensed by an RTD located in the generator. The temperature is sent to the CPU (108) by the Network Device system (109) (120) (121). The refrigerant circulator (113) and the cooling unit (114) are controlled by the contacts directed by the PLC outputs (111) which in turn are

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37/45 controlled by the software protocol. All input and output required to achieve control of the cooling system are listed on the electrical block diagram as: Circulation Pump Relay, Cooling System Relay, Circulation Overload Sensor, Cooling System Overload System, Low Pressure Refrigerant and Refrigerant Flow Switch.

[0081] The vacuum control system includes the vacuum pump 40 and a pressure sensor 104. The start and stop operations of the vacuum pump are controlled according to the control protocol. All input and output required for the vacuum system is listed in the diagram: Vacuum Pump Contact, Sensor not following the Vacuum Pump, Vacuum Pump Overload Sensor, Vacuum Chamber Valve (44), Vacuum Pulse Valve Air (18) and Oxygen Chamber Valve (21). The pressure sensor output is converted by the 15-bit A / D converter (106) and sent to the CPU by the Digital Network Connector (109). The pressure sensor also has two discrete outputs indicating to the CPU (108) the following conditions: Temperature Chamber Pressure Sensor and Chamber Pressure Sensor Heater failure. These two signals are listed on the electrical block diagram as PLC inputs.

[0082] The door actuator system of the sterilization chamber includes a threaded electrical direction and four inductive sensors that allow the detection of the door closing and the locking and unlocking position of the actuator as part of the control protocol. The door opening system is also used in the alarm condition management protocol to ensure user safety. All input and output required to reach the door actuator system is listed in the electrical block diagram as: Door Lock Relay, Door Unlock Relay, Lower Door Closed Sensor (S2), Sensor

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38/45

Upper Door Closed (S1), Door Lock Sensor (S4) and Door Unlock Sensor (S3).

[0083] The ozone energy supply (106) includes a complete rectifier wave, an oscillating circuit and a high voltage transformer. The transformer output is connected to the ozone generator (22). The power supply (power supply) (116) is mounted as a resonator using non-ideal characteristics of the high voltage transformer. CPU 108 controls ozone production and ensures by means of the ozone monitor 104 and the electronic oxygen regulator (126), that the desired concentration for sterilization is achieved and the sterilization cycle is fully maintained. All input and output required by the Ozone Generation System is listed in the diagram as: Oxygen Supply Valve (26), Ozone Chamber Valve (29a), Ozone Dump Catalyst Valve (29b), Ozone Monitor Bypass , High Voltage Standby Relay, High Voltage Current Limiter, High Voltage Ozone Overload Sensor, High Temperature Rectifier Sensor, Ozone Monitor Failure.

[0084] The oxygen supply system is a unit called the Electronic Oxygen Pressure Regulator. A proportional valve (26) that also shuts off oxygen being controlled by an integrated PID circuit converting an analog signal from an absolute pressure sensor (27). The PID then sends the current to the appropriate function cycle to the proportional valve (26). With orifice 28, this system constitutes an oxygen flow regulator. Mechanical regulator 24 is used as a first regulator stage to decrease oxygen pressure from 60 psi to 10 psi. The electronic regulator also provides the alarm condition protocol to ensure user protection. The inputs used for the alarm conditions are listed in the electrical block diagram as: High Oxygen Pressure Sensor and Low Oxygen Pressure Sensor. In addition, the

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39/45 electronic oxygen pressure regulator provides an analog output reader from 0 to 5VDC through the A / D converter 106 through the network device. [0085] The control system is provided with a user interface 118. In the preferred configuration, this interface includes a touch sensitive liquid crystal display (LCD) screen 118, a printer 119 for reporting and a communication port 153 ( RS-232 series) allowing the user to receive and transmit information necessary for the use of the device. It will be apparent to a person skilled in the art, aware of the state of the art, that other types of user interfaces can be used as touch sensitive and similar keyboards, and other types of communication interfaces. The thermal printer status entries appear on the electrical block diagram as: Off-line Printer Sensor, and Paperless Printer.

[0086] H2O2 distribution system control processing [0087] Currently, two configurations of an H2O2 distribution system are possible. The control system can be used for both systems. The first system demonstrated in the present application in Figures 7 and 8 is mainly a bottle of H2O2 (180) flowed into a controlled temperature reservoir (240) in Figure 8. The first system will be described with reference to Figures 7, 8, 9 and 2. All the input and output sensors described below appear in the list of inputs and outputs of the control system listed in Figure 9. When the sterilizer is first started, door 12 is closed and the closed position is felt by switch S7. The bottle is felt in the retainer (S6) by the puncture needle and is also retracted to the top position by the cylinder PA-01 (208). S8 and S9 provide sensation for the upper and lower cylinder positions (208). In addition, the PA-02 actuator is retracted in the unlocked position of the retainer. The user is invited by the message on the screen (118) to open the door (205) and insert a bottle of H2O2 in the retainer. So

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40/45 when the bottle is felt by S6, another message on the screen (118) invites the user to close the door (205) that is felt by S7. The software is controlled by the CPU (108) and condition sensors. The bottle is fixed by gravity on a rotating base (209). The CPU starts the M-02 motor to rotate the bottle 180. A BS-01 bar code reader (Figure 2) (122) Fig. 9 reads the bar code from the bottle. The CPU checks the expiration date of the bottle and if the expiration date expires, the door (205) remains unlocked and a message on the screen (118) invites the user to exchange the bottle for another one. If the date is correct, the CPU stops the M-02 motor and blocks the door (205) by acting PA-02 (Figure 2). Then the CPU acts the cylinder (208) for the needle 209 to pierce the sealed bottle cap until S9 feels the needle in the lower position. Then the bottle is completely emptied into the reservoir 240 by the suction provided through the valve (212) and the vacuum pump (40). The port (205) remains blocked until all H2O2 in the reservoir has been used. Level sensors S10 and S11 provide the necessary conditions for the CPU to estimate whether another bottle will be needed. If positive, the needle is retracted from the bottle and the door (205) is unlocked and the user is invited by a message on the screen (118) to replace the H2O2 bottle.

[0088] Description of the alternative and preferred H2O2 distribution system [0089] The following distribution system does not include the cooled reservoir (240). Instead, H2O2 remains in the bottle (180). The level detectors S10 and S11 are removed and replaced by an ultrasonic level detector that is spring loaded against one side of the bottle near the bottom and used as a low level detector to indicate an empty bottle to the CPU. Because this sensor is spring loaded, it adds a lot of friction to the bottle to use the M-02 engine. Thus, the user is invited by a message on the screen (118) to rotate the bottle manually until the bar code is read by (BS-01) in Figure 2 or (122) in Figure 9. If the bottle is not outside the expiration, the user will be asked to close

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41/45 the port (205) and the CPU blocks the bottle retainer compartment and acts (208) to puncture down the needle. In the preferred configuration, the H2O2 retainer is temperature controlled by a Peltier cell unit. An RTD attached to the retainer and connected to the temperature interface (121) sends the data to the CPU (108) via the Network Device and the CPU controls the PID function of the amount of energy being applied to the Peltier cell unit. The Peltier unit is supplied by the 12VDC power supply (121) also used for the air compressor directing the pneumatic system composed of SV-15, SV-16, the actuators (PA-02 and PA-01) in Figure 2. Between each cycle, the line connected between the H2O2 bottle (180) and the micro-valve module (240) will be purged by SV20. Near the module inlet (240) a hard foam optical detector on the H2O2 line will indicate the total line refill without air on the line.

[0090] Both H2O2 distribution points can supply the micro-valve module (240). The micro-valves (SV-18 and SV-19) work reciprocally for a due cycle program pre-established in a plate micro-controller circuit generating the own time pulses for both micro-valves. The electronic circuit is activated by a signal from the CPU (108), called the H2O2 pump controller signal (Fig. 9). Under the control of the software an appropriate amount of H2O2 is allowed in the humidifying collector (260, Figure 1). This collector is the temperature controlled by the CPU (108) using RTD data (TT-04, Figure 1) and controlling the HTR-01 heater (Fig. 1) by the PID function. Then H2O2 vaporizes the collector (260) and the steam is sent to the chamber under vacuum through the pipe (280, Fig. 1).

[0091] In the preceding description, for the purpose of explanation, numerous details are established in order to provide a complete understanding of the configurations of this invention, however it will be apparent to a technician

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42/45 on the subject, knowing the state of the art that these specific details are not required in order to practice this invention. In other instances, well-known sterilizing structures and circuits are shown in the block diagram or symbol form in order not to obscure this invention. For example, specific details are not provided when certain parts of the sterilizer control are implemented with a software routine, hardware circuit, firmware or a combination thereof.

[0092] The above-mentioned configurations of this invention are intended only as an example. Changes, indications, and variations may be made to the particular configurations by a technician in the subject without departing from the scope of this invention, which is defined solely by the attached claims.

TABLE III

Oxygen circuit FTR-01 Oxygen inlet filter RG-01 Oxygen pressure regulator SV-01 Oxygen supply valve PS-01 Oxygen pressure switch FI-01 Oxygen flow indicator SV-5 Oxygen chamber valve

Ozone circuit Ozone generator TT-01 Temperature transmitter for cooling the generator ozone AOZ-01 Ozone monitor Orifice (used to regulate the flow of ozone to the chamber) SV-02 Ozone chamber valve

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SV-04 Ozone Dump Valve Air circuit AC-01 Air compressor AT-01 Compressed air tank PS-03 Air switch for air compressor RG-03 Air pressure regulator PI-03 Air pressure indicator FTR-03 Air inlet filter Aluminum block TT-04 Aluminum block temperature transmitter HTR-01 Heating element STERIZONE solution circuit SV-17 H ₂ O ₂ filling valve SV-21 H ₂ O ₂ ventilation valve SV-18 H ₂ O ₂ inlet valve SV-19 H ₂ O ₂ outlet valve SV-20 H ₂ O ₂ removal valve Supply system for the STERIZONE Solution S6 Sensor (detects the absence-presence status in the STERIZONE solution container) S7 Sensor (detects the open-closed state of the STERIZONE solution compartment) S8 Sensor (detects the top position PA-01) S9 Sensor (detects the lower position PA-01) S12 Sensor (detects the locked-unlocked state of the STERIZONE solution compartment) S13 Sensor (detects the open-closed state (fascia) of the solution compartment STERIZONE)

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S14 Sensor (detects the lower level of H ₂ O ₂ in the bottle) S15 Sensor (detects the lower level of H ₂ O ₂ in the bottle) SV-15 Pilot air valve for puncture needle actuators

PM-900-014 SV-16 Pilot air valve for blocking actuators STERIZONE Solution compartment B-01 Bottom of the customized tapered bottle of the Solution STERIZONE BS-01 Bar Code Reader for bottle PA-01 Pneumatic actuator for bottle punching PA-02 Pneumatic actuator for blocking the STERIZONE solution PA-03 Pneumatic actuator for puncture needle centering M-02 Electric motor that turns the bottle by reading the bar code CS-01 Bottle Cooling System VS-02 Vacuum switch (to fill and remove the H ₂ O _{2 line} Sterilization Chamber S1 Top closed door switch S2 Bottom switch closed for door S4 Locked door switch S3 Unlocked door switch PT-01 Chamber Pressure Transmitter VS-01 Water Switch TT-03,5,6 Chamber Temperature Transmitters TT-07 Chamber Door Temperature Transmitter Vacuum Circuit SV-06 Chamber Vacuum Valve M-01 Vacuum pump operating status indicator

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M-01 Vacuum pump contactor CAT-01 Catalytic converter Catalyst Drying Circuit FTR-02 Door Silencer SV-11 Catalytic to Air Converter Valve (Drying Valve catalyst) PM-900-002 Cooling Circuit FS-02 Refrigerant Flow Switch M-05 Circulation pump operating status indicator M-05 Blood pressure contactor Overload Circulation Pump PS-02 Compressor low pressure switch M-06 Compressor operating status indicator M-06 Compressor Contactor Compressor Overload

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Claims (3)

1 “METHOD OF CONTROL OF AN UNWANTED HYDROGEN PEROXIDE CONDENSATION IN A PRE-SELECTED TEMPERATURE STERILIZATION CHAMBER” characterized by understanding the maintenance steps of the sterilization chamber (10) at a vacuum pressure below the pressure at which hydrogen peroxide (30) will boil at a pre-selected temperature; evaporation of successive pulses of hydrogen peroxide (30), and the injection of hydrogen peroxide (30) evaporated into the chamber, thereby the volume of each pulse of hydrogen peroxide is less than 75 pL. 2. "METHOD" according to claim 1, characterized in that the pulse volume is less than 35 pL. 3. "METHOD" according to claim 2, characterized in that the pulse volume is less than 20 pL. Petition 870180044981, of 05/27/2018, p. 51/54 1/12 12/2 PW 12/3