AU2013201197B2 - Sterilization apparatus - Google Patents

Abstract

A hydrogen peroxide delivery system for a sterilizer having a hydrogen peroxide injection unit and a housing is disclosed. The system includes a cradle for supporting a hydrogen peroxide solution container, a drainage arrangement for aspirating the hydrogen peroxide solution from the container, and a delivery arrangement for supplying the aspirated hydrogen peroxide solution to the hydrogen peroxide injection unit. The drainage arrangement includes a needle for penetrating a seal on the container and extending into the hydrogen peroxide solution in the container. A needle drive moves the needle from an at rest position, wherein the needle is retracted to allow insertion of a new hydrogen peroxide container into the cradle, to a penetrating position wherein the needle penetrates the seal of the container and extends all the way to the bottom of the container to ensure complete drainage of the hydrogen peroxide solution from the container. (Figure 1) OzoeGenertor 2 Ozone r 28 29b Pressiepeg tr Oribc RG-01 2 TR7240 20 --- s--- qoi sN s 29 1 2- 2 2 |0supp 28 100R r - ---- ----- - - - - - - - F.. ...-.. .2. RG-01HT-0 221 40-0 g.hl Cab _e A.01 200 SV-S1 265 220 -jSV-17 p FIG. 1 ----_ _ _ ___ _ _ 222 -- - - - 2 - -

Description

1 STERILIZATION APPARATUS Related Application [0001] This application is a divisional of Australian patent application no. 5 2010302888, the content of which is incorporated into the present application in its entirety. Field of the Invention [0002] The present invention relates generally to sterilization apparatus. 10 More particularly, the present invention relates to a hydrogen peroxide delivery system for a sterilization apparatus using gaseous hydrogen peroxide under vacuum. Background of the Invention 15 [0002a] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. [0003] Sterilization is the destruction of any virus, bacteria, fungus or other micro-organism, whether in a vegetative or in a dormant spore state and is defined 20 by a 10-6 reduction in the level of bacteria. Conventional sterile processing procedures for medical instruments involve high temperature (such as steam and dry heat units) or chemicals (such as ethylene oxide gas, hydrogen peroxide, or ozone). [0004] Sterilization methods and apparatus using gaseous sterilants are well 25 known. Sterilizers using hydrogen peroxide as the sterilant are widely used. The hydrogen peroxide is generally supplied as an aqueous solution and evaporated prior to injection into a sterilization chamber of the sterilizer, by heating of the solution, or by applying a vacuum to the sterilization chamber, or both. After evaporation of the solution, the sterilization atmosphere in the sterilization chamber 30 includes water vapor and hydrogen peroxide gas. It is a disadvantage of this process that the water vapor tends to condensate on articles in the chamber as the sterilization proceeds. The resulting layer of water condensate on the articles to be sterilized interferes with the sterilizing action of the hydrogen peroxide. Numerous apparatus and process modifications have been developed to address this problem, 35 all of which are aimed at limiting the relative humidity in the sterilization atmosphere 2 during the sterilization process. However, these modifications invariably increase operating cost and/or sterilization cycle times. [0005] Sterilizers using ozone containing gas as the sterilant are also known. The ozone gas is generally produced externally to the sterilization chamber 5 and supplied into the chamber under vacuum to increase penetration of the sterilant gas into restricted spaces on the articles to be sterilized. In order to improve the sterilization effect of ozone gas, the sterilization atmosphere is generally humidified with water prior to the injection of ozone gas into the sterilization chamber. However, the amount of ozone gas needed is relatively high (85mg/I) and the sterilization 10 cycle times are relatively long, making ozone based sterilization processes comparatively expensive. Furthermore, many articles to be sterilized are damaged by the high levels of ozone required to achieve complete sterilization and can therefore not be sterilized in an ozone sterilization process. [0006] Sterilization processes using both hydrogen peroxide gas and ozone 15 gas have been used, but with unsatisfactory results especially with respect to the sterilization of articles with long internal lumens, such as gastroscopes and colonoscopes, and with respect to cycle times and sterilization cost. Although ozone based processes are satisfactory with respect to sterilization of articles with long lumens, material compatibility represents a problem. Hydrogen peroxide based 20 processes are generally unsatisfactory regarding the sterilization of long lumens. [0007] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. In general, a method and apparatus is desired which may address at least one of the disadvantages of known sterilization processes using gaseous sterilants. It is an 25 object of an especially preferred form of the present invention to provide a system to obviate or mitigate at least one disadvantage of previous sterilant delivery systems. [0008] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; 30 that is to say, in the sense of "including, but not limited to". [0009] Although the invention will be described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. 35 3 Summary of the Invention [0010] According to a first aspect of the present invention there is provided a hydrogen peroxide delivery system for a sterilizer having a hydrogen peroxide injection unit and a housing, comprising 5 a cradle for supporting a sealed hydrogen peroxide solution container in an upright position within the housing, a drainage arrangement connected with the cradle for aspirating the hydrogen peroxide solution from the container, and a delivery arrangement connected with the drainage arrangement for 10 supplying the aspirated hydrogen peroxide solution to the hydrogen peroxide injection unit, the drainage arrangement including a drainage needle connected with the delivery arrangement for penetrating a seal on the container and extending into the hydrogen peroxide solution in the container, and a needle drive for moving the needle from an at rest position, wherein 15 the needle is retracted to allow insertion of a new hydrogen peroxide container into the cradle, to a penetrating position wherein the needle penetrates the seal of the container and extends into the hydrogen peroxide solution in the container, the needle extending all the way to a bottom of the container in the penetrating position. 20 [0011] According to a second aspect of the present invention there is provided a hydrogen peroxide solution container for use in a delivery system as defined according to the first aspect of the present invention, the sealed hydrogen peroxide solution container comprising a hollow body with a top end including a 25 sealed fill and drainage opening, a side wall and a conical bottom, a stand for maintaining the container in an upright position on a flat horizontal surface prior to insertion into the cradle and a connecting arrangement for connecting the stand to the body. [0012] In one form, the disclosure provides a hydrogen peroxide delivery 30 system for a sterilizer having a hydrogen peroxide injection unit and a housing. The system includes a cradle for supporting a sealed hydrogen peroxide solution container within the housing, a drainage arrangement connected with the cradle for aspirating the hydrogen peroxide solution from the container, and a delivery arrangement connected with the drainage arrangement for supplying the aspirated 35 hydrogen peroxide solution to the hydrogen peroxide injection unit.

4 [0013] In a further form, the drainage arrangement includes a drainage needle connected with the delivery arrangement for penetrating a seal on the container and extending into the hydrogen peroxide solution in the container, and a needle drive for moving the needle from an at rest position, wherein the needle is 5 retracted to allow insertion of a new hydrogen peroxide container into the cradle, to a penetrating position wherein the needle penetrates the seal of the container and extends into the hydrogen peroxide solution in the container. Preferably, the needle extends all the way to a bottom of the container in the penetrating position. Most preferably, the needle drive is reciprocatable. 10 [0014] In another form, the disclosure provides a hydrogen peroxide delivery system, wherein the container includes a stand for supporting a hydrogen peroxide solution container in an upright position within the housing. Preferably, the needle drive is reciprocatable for moving the needle from an at rest position, wherein the needle is retracted to allow insertion of a new hydrogen peroxide container in the 15 stand, to a penetrating position wherein the needle penetrates the seal of the container and extends into the hydrogen peroxide solution in the container, the needle extending all the way to a bottom of the container in the penetrating position. [0015] In still a further form, the delivery system of the present disclosure uses a hydrogen peroxide solution container with a conical bottom, whereby the 20 conical bottom of the container is centered with an axis of the drainage needle for aligning a tip of the needle with the lowest point of the bottom. [0016] In yet another form, the present disclosure provides a sealed hydrogen peroxide solution container including a hollow body with a top end including a sealed fill and drainage opening, a side wall and a conical bottom, a 25 stand for maintaining the container in an upright position on a flat horizontal surface prior to insertion into the cradle and a connecting arrangement for connecting the stand to the body, whereby the bottom of the container is conical to ensure any residual hydrogen peroxide solution collects at a lowest point of the bottom. Preferably, the stand is snap fitted onto the hollow body. More preferably, the 30 container includes an external recess in the side wall of the body and the stand is cup-shaped and has a radially inwardly extending tab for engagement with the recess to provide a snap fit connection of the stand to the body. Most preferably, the recess is a circumferentially extending, continuous groove and the stand includes at least two tabs for engagement of the groove.

4a [0017] Other aspects and features of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures. 5 Brief Description of the Drawings [0018] A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: [0019] Embodiments of the sterilizer, method and delivery system of this 10 disclosure will now be described, by way of example only, with reference to the attached Figures, wherein: [0020] FIG. 1 shows a schematic diagram of an apparatus in accordance with the disclosure, the illustrated parts of the apparatus being listed in Table Ill; [0021] FIG. 2 shows a schematic diagram of a hydrogen peroxide delivery 15 system in accordance with the disclosure, the illustrated parts of the system being listed in Table Ill;; [0022] FIG. 3 is a flow diagram of a preferred sterilization method; [0023] FIG. 4 is a graph illustrating a first exemplary sterilization cycle; [0024] FIG. 5 is a graph illustrating a second exemplary sterilization cycle; 20 [0025] FIG. 6 is a graph illustrating a third exemplary sterilization cycle; [0026] FIG. 7 shows an exemplary embodiment of a hydrogen peroxide supply unit in accordance with the disclosure; [0027] FIG. 8 shows an exemplary embodiment of a hydrogen peroxide reservoir, metering and evaporation assembly; 25 [0028] FIG. 9 is a schematic diagram of an exemplary control system; [0029] FIG. 1 0a is a perspective view of a sterilant container in accordance with the invention; [0029a] FIG. 1Ob is a cross-sectional view of the container of FIG, 10a; [0029b] FIG. 1 Oc is a side elevational view of the container of FIG. 1 Oa; and 30 [0029c] FIG. 1 Od is enlarged detail B of the container shown in FIG. 1Ob. Detailed Description of the Preferred Embodiment [0029d] Generally, the present disclosure provides a hydrogen peroxide delivery system for use in methods and systems for sterilization of an article in a 35 sterilization atmosphere by adding evaporated hydrogen peroxide.

4b [0030] The delivery system can be used, for example, in a method of sterilizing an article by exposure to hydrogen peroxide and ozone, as illustrated in the flow diagram of FIG. 3 and the cycle graphs of FIG.s 4 to 6. In that method, the article is exposed under vacuum first to an evaporated aqueous solution of 5 hydrogen peroxide and subsequently to an ozone containing gas. Preferably, the sterilization process is achieved while the chamber remains sealed and under vacuum. For this purpose, the 5 chamber is initially evacuated to a first vacuum pressure sufficient to cause evaporation of the aqueous hydrogen peroxide at the temperature of the chamber atmosphere. The chamber is then sealed and hydrogen peroxide and ozone containing gas are sequentially added to the chamber and maintained in the chamber for a preselected 5 exposure time. All removal of any components in the sterilization atmosphere is stopped during addition of the sterilants 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. [0031] The delivery system can be used in an exemplary sterilizer as illustrated 10 schematically in FIG. 1, which sterilizer operates generally in the following manner. An article to be sterilized (not shown) is placed into a sterilization chamber 10 and the chamber is sealed. A vacuum is applied to the chamber 10. Evaporated hydrogen peroxide solution is supplied into the sterilization chamber 10 from a delivery unit 30 (see FIG. 8), which will be discussed in more detail below. The evaporated hydrogen 15 peroxide supplied into the chamber provides a partial sterilization of the article. Medical quality oxygen is subjected in an ozone generator 22 to an electrical field, which converts the oxygen into ozone containing gas. The ozone containing gas is then fed into the chamber 10, which has been humidified by the injection of the evaporated hydrogen peroxide solution and the decomposition of the hydrogen peroxide into free 20 radicals (hydroxyls), water and oxygen. The ozone containing gas finishes the sterilization of the article. Remaining sterilant gases are subsequently decomposed into water and oxygen using a catalyst 52. The only residues left at the end of the sterilization cycle are oxygen and clean water. [0032] The use of a delivery system in accordance with the present disclosure 25 allows for a hydrogen peroxide sterilization method to be carried out without the handling of dangerous gas cylinders, and poses no threat to the environment or the user's health. [0033] An exemplary sterilization apparatus in connection with which the delivery system of the present disclosure can be used is illustrated schematically in 30 FIG. 1. The exemplary apparatus includes a sterilization chamber 10 which can be sealed to contain a vacuum. This is achieved with an access door 12, which can be selectively opened for access into the chamber and which seals the chamber in the closed condition. The apparatus further includes an ozone generator 22 for supplying ozone-containing gas to the sterilization chamber, a hydrogen peroxide delivery unit 30 6 for supplying evaporated hydrogen peroxide to the sterilization chamber 10, and a vacuum pump 40 (CM-005-052 TSO3, Inc.). The vacuum pump 40 is used for the application of a sufficient vacuum to the sterilization chamber 10 to increase the penetration of the sterilizing gas and to be able to generate evaporated hydrogen 5 peroxide solution at a temperature below the temperature inside the sterilization chamber. The vacuum pump 40 in the preferred embodiment is capable of producing a sufficient vacuum in the sterilization chamber to lower the boiling point of water in the chamber below the actual temperature of the atmosphere in the chamber. In the preferred apparatus, the vacuum pump is capable of producing a vacuum of 1 Torr 10 (1.33mbar). For economic and practical reasons, it is preferred to use a catalyst for decomposition of the sterilant in the sterilization gas exhausted from the sterilization chamber 10. The catalyst destroys hydrogen peroxide on contact and retransforms it into oxygen and water with a certain amount of heat being produced. Catalysts of this type and their manufacture are well known to the person skilled in the art and need not 15 be described in detail herein. Furthermore, other means for destroying hydrogen peroxide contained in the sterilization gas will be readily apparent to a person skilled in the art. For example, the gas can be heated for a preselected time to a temperature at which the sterilant decomposition is accelerated, for example, to 3000C for a period of 3 seconds. 20 [0034] The hydrogen peroxide delivery unit 30 includes a reservoir 220 (AM 213-010, TSO 3 Inc.), a metering unit 240, and an evaporator unit 260 (FM-213-003,

TSO

3 Inc.) directly connected to the sterilization chamber 10 through a conduit 280. (AM-213-003, TSO 3 Inc.) The reservoir 220 is equipped with a level sensor 222 to always ensure a sufficiently high level of hydrogen peroxide for the execution of 25 another sterilization cycle. A hydrogen peroxide solution (3-59%) is supplied to the reservoir from a hydrogen peroxide supply unit 200 (see FIG. 7), which will be discussed in more detail below. The hydrogen peroxide solution is supplied into the supply unit 200 from a sealed hydrogen peroxide solution container, in this embodiment a bottle 180 (see FIG. 7). The evaporated hydrogen peroxide solution 30 produced in the evaporator unit 260 directly enters the sterilization chamber 10 with no intermediate flow restriction or valve. The evaporator unit is preferably equipped with a heating device (not shown) that maintains the temperature of the hydrogen peroxide solution sufficiently high to achieve a higher evaporation rate and prevent freezing of the solution.

7 [0035] The ozone generator 22 (OZ, model 14a, TSO 3 Inc.) is of the corona discharge type and is cooled to decrease the ozone decomposition rate, all of which is well known in the art. [0036] The vacuum in the sterilization chamber 10 is produced by way of the 5 vacuum pump 40 and the sterilization chamber drainage valve 44. [0037] Valves 29a and 29b are Teflon solenoid valves (CM-900-156, TSO3 Inc.) Valve 26 and vacuum valve 44 are solenoid valves (CM-015-004, TSO3 Inc.). [0038] The preferred ozone generator used in the process and apparatus of the invention is a generator of the corona discharge type, which is well known to the 10 person skilled in the art and need not be further described herein. Operation [0039] An exemplary sterilization method includes the following general steps as illustrated by the flow chart of FIG. 3. Articles to be sterilized, such as medical 15 instruments, can be placed directly into the sterilization chamber, but are preferably sealed in sterile packaging containers, sterile wraps or pouches such as generally used in the hospital environment and then placed into the sterilization chamber. [0040] After insertion of the article to be sterilized has been placed into the sterilization chamber in step 320, the door of the sterilization chamber is closed and the 20 chamber sealed in step 340 and a vacuum is applied to the sterilization chamber in step 350 until a first pressure of 1 Torr (1.33 mbar) is reached in the chamber. The sterilization chamber walls have preferably been preheated in a warm-up step 310 to a temperature of 400C. Evaporated hydrogen peroxide solution is admitted into the sterilization chamber in humidification step 360 to partially sterilize and humidify the 25 chamber contents. The injection of evaporated hydrogen peroxide solution is stopped once a pressure increase of 19 Torr has been achieved in the chamber. The chamber can be maintained sealed for a first exposure period 370 (preferably 2 minutes) during which the hydrogen peroxide at least partially decomposes into free radicals, water and oxygen. This exposure period can also be omitted. An ozone containing gas, preferably 30 in the form of a mixture of dry ozone and oxygen is then supplied to the chamber in the ozone injection step 380 and the chamber maintained sealed for a preselected second exposure period 390. No humidification of the ozone containing gas is carried out, or is even necessary, since the chamber atmosphere has been humidified by the hydrogen peroxide solution. Between the application of the vacuum, before the hydrogen 8 peroxide evaporation step, and the end of the second exposure period, all removal of any sterilization atmosphere components is interrupted so that none of the components of the atmosphere are removed before the end of the second exposure period. The steps of vacuum application, hydrogen peroxide injection with first exposure period and 5 ozone gas injection with second exposure period, are preferably repeated at least once, the number of repetitions being determined in step 395 on the basis of the cycle chosen previously in step 330. To remove all remaining sterilants from the sterilization chamber 10 after the sterilization cycle is completed a ventilation phase 400 is commenced, which preferably includes multiple cycles of evacuation of the chamber 10 and flushing with oxygen. After the ventilation phase 400, the door is unlocked in step 410 and the sterilized articles can be taken from the chamber. The temperature of the floor and door of the chamber and of the evaporator unit is preferably controlled throughout the sterilization process. [0041] In an exemplary sterilization apparatus, the user has the choice of 15 multiple different sterilization cycles. In a preferred method, the user can choose in cycle selection step 330 of the process among three cycles which 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 Humidification with 50% H202 20 Torr 20 Torr 20 Torr solution Humidification plateau (optional) 2 min 2 min 2 min 03 Injection 2 mg/1 10 mg/L 3 mg/L Exposure 5 min 5 min 10 min Nb of repetition(s) 2 2 4 Approx. Cycle duration 46 min 56 min 100 min 20 Cycle 1- Surface sterilization of devices having low compatibility with ozone, hinged devices and short flexible endoscopes (1 mm x 85 cm). (Ex. Cameras, cables, paddles, forceps, bronchoscopes, ureteroscopes). Cycle 2- Surface devices with high compatibility with ozone, hinged 25 instruments and rigid endoscopes (1 mm x 50 cm).

9 Cycle 3- Instruments sterilizable with cycle #1 and complex endoscopes (Ex. gastroscopes, colonoscopes). [0042] Although it is preferred to operate the exemplary sterilization process 5 using a 50% hydrogen peroxide solution, the process can be operated with solutions including 3% -50% hydrogent peroxide. Exemplary conditions for the process when operated with a 3%, 30% and 50% hydrogen peroxide solution are as follows. Table || % H 2 0 2 Max Injection Ozone dose No of Conditioning Pressure (mg/L) repetitions time (Torr) 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 10 [0043] The maximum injection pressure is the pressure at which injection of the evaporated hydrogen peroxide solution is stopped. The conditioning time represents a time period after sealing of the chamber and prior to application of the vacuum in which the articles to be sterilized are maintained in the sterilization chamber and gradually 15 warm up from room temperature due to the chamber walls, floor and door being heated to about 40'C. This warming up of the load in the chamber is required to prevent undue condensation of water on the load on injection of the evaporated hydrogen peroxide solution. The risk of condensation increases with decreasing hydrogen peroxide solution concentrations. 20 [0044] Once the user has chosen one of the three cycles, the user closes the sterilization chamber door and pushes the start button. The sterilizer control system (see FIG. 9) will then, under the control of a built in operating software, start the sterilization process according to the cycle chosen and using preselected parameters for the cycle chosen. The cycle starts with the generation of a vacuum in the 25 sterilization chamber of approximately 1 Torr (1.33mbar). An evaporated aqueous hydrogen peroxide solution is subsequently injected into the chamber through the evaporator unit to partially sterilize and humidify the load. Before entering the 10 evaporator unit, the hydrogen peroxide solution passes through the metering unit 240 shown in FIG. 8. The metering unit 240 is directly connected to the evaporator unit 260 and, thus, subjected to the vacuum pressure present in the chamber. The metering unit 240 includes a base block 241 having a passage of a fixed, known volume (not shown) 5 and connected by an intake valve 242 at an upstream end of the passage to the hydrogen peroxide reservoir 220 and by an exhaust valve 243 at a downstream end of the passage to the evaporator unit 260. The flow of hydrogen peroxide solution through the metering unit 240 can be exactly controlled by way of the valves 242, 243, which are switched oppositely and non-overlapping so that one valve is always closed when 10 the other is open and both valves are never open at the same time. In this manner, the passage is evacuated when the exhaust valve 243 is open and the intake valve 242 is closed, filled with hydrogen peroxide solution when the exhaust valve 243 is closed and the intake valve 242 is open and evacuated again when the exhaust valve 243 is again open and the intake valve 242 is again closed. Since the exact volume of the passage 15 is known, the amount of hydrogen peroxide solution supplied per valve cycle is known and the total amount of hydrogen peroxide can be calculated on the basis of the number of valve switching cycles. The number of times and the frequency that the valves 242, 243 open and close are controlled and monitored by apparatus software and can be used to determine the amount of hydrogen peroxide solution removed from 20 the reservoir and to calculate the theoretically remaining amount of solution in the reservoir, based on the total amount aspirated from the supply bottle and the metered amount. [0045] As shown in FIG.s 2 and 7, the hydrogen peroxide delivery system 200 of this disclosure intended for a sterilizer having a hydrogen peroxide injection unit and a 25 housing, includes a bottle holder or cradle 202 for supporting a sealed hydrogen peroxide solution container 180 in an upright position within the housing (not shown), a drainage arrangement 207 connected with the cradle for aspirating the hydrogen peroxide solution from the container 180, and a delivery arrangement connected with the drainage arrangement for supplying the aspirated hydrogen peroxide solution to the 30 hydrogen peroxide injection unit. The drainage arrangement 207 includes a drainage needle 209 connected with the delivery arrangement for penetrating a seal on the container 180 and extending into the hydrogen peroxide solution in the container, and a needle drive 208 for moving the needle from an at rest position, wherein the needle is retracted to allow insertion of a new hydrogen peroxide container into the cradle, to a 11 penetrating position wherein the needle penetrates the seal of the container and extends into the hydrogen peroxide solution in the container. In the penetrating position, the needle preferably extends all the way to a bottom of the container. [0046] In a preferred embodiment, the delivery system includes a bottle holder 5 202 for receiving a sealed hydrogen peroxide solution bottle 180. The holder has a bottle seat or cradle 204 in which the bottle 180 is fittingly received. The bottle 180, which will be discussed in more detail further below, is held in the seat 204 by gravity only. The holder 202 is rotatably mounted on pivot 203 for movement between an open position as illustrated in FIG. 7, which the bottle 180 can be placed into or removed 10 from the holder and a closed position in which the holder is completely within the sterilizer cabinet or housing (not shown) and a front cover 205 of the holder closes off all access to the holder from outside the cabinet. When the holder 202 is in the closed position, a pneumatically driven drainage arrangement 207, including a needle drive, in this embodiment a vertically oriented pneumatic cylinder 208, and a drainage needle 15 209 mounted on the piston rod 210 of the cylinder, is activated to drain all hydrogen peroxide solution from the bottle 180. This is achieved by activating the cylinder 208 to force needle 209 through the bottle seal until the needle tip reaches the bottom of the bottle 180. The needle 209 is fluidically connected to the reservoir 240 (see FIG. 8) and the solution is aspirated from the bottle 180 and into reservoir 240 by using the vacuum 20 generated by the vacuum pump 44 to which the reservoir 240 can be fluidically connected by conduit 211 and valve 212 (see FIG. 1). Once the contents of the bottle 180 have been aspirated, the holder can be opened and the bottle removed, or the empty bottle can be kept in the holder until a refill of the reservoir 240 is required. The reservoir 240 is provided with a level sensor 242 which provides a signal to the control 25 system on the liquid level in the reservoir. Based on the signal received from the sensor 242, the control system notifies the user if the amount of liquid in the reservoir 240 is insufficient for the execution of the cycle selected by the user. [0047] In an alternate embodiment, the hydrogen peroxide delivery system does not include a reservoir. Instead, the bottle 180 itself is cooled down (CS-01) to 30 avoid rapid degradation of the aqueous hydrogen peroxide. A sensor (S14) measures the amount of solution left in the bottle. When the solution reaches a 1 S preselected level, a 1 St warning appears on the screen and when a lower, 2 nd preselected level is reached, the message generated from the software to the operator specifies that only 12 one more sterilization cycle #1 or #2 can be run with the remaining solution in the bottle. The operator will then have to reload the delivery system with a fresh, full bottle. [0048] As shown in FIG.s 10a to 1Od, the bottle 180 has a conical bottom 182 to ensure a complete drainage of all liquid in the bottle, thereby reducing the danger of 5 spills or contamination on removal of a drained bottle. In order to ensure the bottle 180 securely remains upright, a stand 184 is attached to the bottom end of the bottle. The stand 184 includes an upturned cup 185 snap fitted into a circumferential groove 186 on the bottle exterior wall 187. The needle 209 is aligned with the lowest point in the bottle bottom and can be moved into the bottle, through the bottle seal, until it reaches 10 the lowest point in the bottle. Mechanical, electronic or other control structures and functions are provided to ensure contact of the needle with the bottle bottom while preventing penetration of the bottle bottom. A pressure sensor is preferably incorporated into the needle drive and/or the needle mount (not shown). [0049] In the preferred embodiment, the needle drive is reciprocatable for 15 moving the needle back and forth between the at rest and penetrating positions, whereby in the at rest position the needle is retracted to allow insertion of a new hydrogen peroxide container and in the penetrating position the needle penetrates the seal of the container and extends into the hydrogen peroxide solution in the container all the way to the bottom of the container. 20 H202 dispensing system control processing [0050] At the moment, two configurations of an H202 dispensing system are possible. The control system could be used for both systems. The first system depicted in the present application in Fig 7 and Fig 8 is mainly a bottle of H202 (180) flushed 25 into a temperature controlled reservoir (240) Fig 8. This first system will be described with reference to FIG.s 7,8,9 and 2. All input and output sensors described in the following appear in the list of inputs and outputs of the control system listed on Fig 9. When the strerilizer is first initialized, the door 12 is closed and the closed position is sensed by switch S7. No bottle is sensed in the holder by (S6), the puncture needle is 30 also retracted to the up position by the cylinder PA-01 (208). S8 and S9 provide sensing for the upward and downward position of cylinder (208). Also, actuator PA-02 is retracted in the holder unlocked position. The user is invited by the message on the screen (118) to open the door (205) and to insert a H202 bottle in the holder. So when the bottle is sensed by S6, another message on the screen (118) invites the user to 13 close the door (205) which is sensed by S7. Software control is carried out by the CPU (108) and condition sensors. The bottle is set by gravity on a rotating base (209). The CPU starts the motor M-02 to rotate the bottle 180. A bar code reader BS-01 (FIG. 2,) (122) FIG. 9 reads a bar code on the bottle. The CPU verifies the expiry date of the 5 bottle and if the bottle is past its expiry date, the door 205 remains unlocked and a message on the screen (118) invites the user to change the bottle for another one. If the date is correct, the CPU stops the motor M-02 and locks the door (205) by actuating PA-02 (Fig 2). Then CPU actuates the cylinder (208) for the needle 209 to perforate the sealed cap of the bottle until S9 senses the needle in the down position. 10 Then the bottle is totally emptied into the reservoir 240 by suction provided through valve (212) and vacuum from pump (40). The door (205) remains locked until all the H202 in the reservoir has been used. Level sensors S10 and S11 provide the conditions necessary for the CPU to estimate if another bottle is needed. If so, the needle is retracted from the bottle and the door (205) is unlocked and the user is 15 invited by a message on the screen (118) to replace the H202 bottle. Description of the alternate and preferred H202 dispensing system [0051] The following dispensing system does not include the cooled reservoir (240). Instead, the H202 remains in the bottle (180). Level detectors S10 and S11 are 20 removed and replaced by an ultrasonic level detector which is spring loaded against a side of the bottle near the bottom and used as a low level detector to indicate to the CPU an empty bottle. Because this sensor is spring loaded, it adds too much friction on the bottle to use the motor M-02. Therefore, 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) Fig 2 or 25 (122) fig 9. If the bottle is not out of date, the user is invited to close the door (205) and the CPU locks the compartment of the bottle holder and actuates (208) to puncture down the needle. In that preferred embodiment, the H202 holder is temperature controlled by a Peltier cell unit . An RTD attached to the holder and connected to the temperature interface (121) sends data to the CPU (108) by Device Net network and 30 the CPU controls by PID function the amount of power being applied to the Peltier cell unit. The Peltier unit is supplied by the 12VDC (121) power supply used also for the air compressor driving the pneumatic system composed of SV-15, SV-16, actuators (PA 02 and PA-01) on Fig 2 . Between each cycle, the line connected between the H202 bottle (180) and micro valve module (240) will be purged by SV20. Near the inlet of 14 module (240) a foam optical detector snapped on the H202 line will indicate the total refill of the line without air in the line. [0052] To that point both H202 dispensing systems can supply the micro valves module (240). The micro valves (SV-1 8 and SV1 9) are working reciprocally for a 5 preset duty cycle program on an on board microcontroller circuit generating the proper timing pulses for both micro-valves. That electronic circuit is activated by a signal from the CPU (108) called H202 pump controller signal FIG 9. Under software control, a proper amount of H202 is allowed in the humidifier manifold (260, Fig1). This manifold is temperature controlled by the CPU (108) using data of RTD (TT-04, Fig. 1) and 10 controlling heater HTR-01 (Fig. 1) by PID function. Then the H202 vaporizes in the manifold (260) and the vapor is sent to the chamber under vacuum through pipe (280, Fig. 1). [0053] In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments 15 of the invention. However, it will be apparent to one skilled in the art that these specific details are not required in order to practice the invention. In other instances, well known sterilizer structures and circuits are shown in block diagram or symbol form in order not to obscure the invention. For example, specific details are not provided as to whether certain parts of the sterilizer controls are implemented as a software routine, 20 hardware circuit, firmware, or a combination thereof. [0054] The above-described embodiments of the invention are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto. 25 TABLE III Oxygen Circuit FTR-0 1 Oxygen Inlet Filter RG-01 Oxygen Pressure Regulator SV-0 1 Oxygen Supply Valve PS-01 Oxygen Pressure Switch FI-0 1 Oxygen Flow Indicator SV-05 Oxygen To Chamber Valve Ozone Circuit 15 Ozone Generator TT-01 Temperature Transmitter for Ozone Generator Cooling AOZ-01 Ozone Monitor Orifice (used to regulate ozone flow to chamber) SV-02 Ozone To Chamber Valve SV-04 Ozone Dumped Valve (By-pass) Air Circuit AC-01 Air Compressor AT-01 Compressed Air Tank PS-03 Pressure Switch For Air Compressor RG-03 Air Pressure Regulator PI-03 Air Pressure Indicator FTR-03 Air Inlet Filter Aluminium Block TT-04 Aluminium Block Temperature Transmitter HTR-01 Heating Element STERIZONE Solution Circuit SV-17 H 2 0 2 Filling Valve SV-21 H 2 0 2 Vent Valve SV-18 H 2 0 2 Inlet Valve SV-19 H 2 0 2 Outlet Valve SV-20 H 2 0 2 Purge Valve STERIZONE Solution Supply System S6 Sensor (detects STERIZONE Solution container presence-absence status) S7 Sensor (detects STERIZONE Solution compartment open-close status) S8 Sensor (detects PA-01 upper position) S9 Sensor (detects PA-01 lower position) S12 Sensor (detects STERIZONE Solution compartment locked-unlocked status) S13 Sensor (detects STERIZONE Solution compartment access (fascia) opened-closed status) S14 Sensor (detects the lower level of H 2 0 2 in the bottle) S15 Sensor (detects presence of air bubble in the line) SV-15 Air pilot valve for needle puncture actuators PM-900-014 SV-16 Air pilot valve for STERIZONE Solution compartment lock actuator B-0 1 Custom taper shape bottom STERIZONE Solution bottle BS-01 Barcode scanner for bottle PA-01 Pneumatic actuator for bottle puncture PA-02 Pneumatic actuator for STERIZONE Solution compartment lock PA-03 Pneumatic actuator for puncture needle centering M-02 Electric motor that rotate bottle for barcode scanning 16 CS-01 [Cooling system for the bottle VS-02 IVacuum switch (to fill and purge H202 line) Sterilization Chamber Sl Door Closed Upper Switch S2 Door Closed Lower Switch S4 Door Locked Switch S3 Door Unlocked Switch PT-0 1 Chamber Pressure Transmitter VS-01 Chamber Vacuum 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 Run Status Flag M-01 Vacuum Pump Contactor CAT-01 Catalytic Converter Catalyst Drying Circuit FTR-02 Port Muffler SV-1 1 Air to Catalytic Converter Valve (Catalyst Dryer Valve) PM-900-002 Cooling Circuit FS-02 Coolant Flow Switch M-05 Circulation Pump Run Status Flag M-05 Circulation Pump Contactor Overload Circulation Pump PS-02 Compressor Low Pressure Switch M-06 Compressor Run Status Flag M-06 Compressor Contactor Overload Compressor

Claims (17)

1. A hydrogen peroxide delivery system for a sterilizer having a hydrogen peroxide injection unit and a housing, comprising 5 a cradle for supporting a sealed hydrogen peroxide solution container in an upright position within the housing, a drainage arrangement connected with the cradle for aspirating the hydrogen peroxide solution from the container, and a delivery arrangement connected with the drainage arrangement for 10 supplying the aspirated hydrogen peroxide solution to the hydrogen peroxide injection unit, the drainage arrangement including a drainage needle connected with the delivery arrangement for penetrating a seal on the container and extending into the hydrogen peroxide solution in the container, and a needle drive for moving the needle from an at rest position, wherein the needle is 15 retracted to allow insertion of a new hydrogen peroxide container into the cradle, to a penetrating position wherein the needle penetrates the seal of the container and extends into the hydrogen peroxide solution in the container, the needle extending all the way to a bottom of the container in the penetrating position. 20

2. A delivery system according to claim 1, wherein the needle drive is reciprocal for moving the needle back and forth between the at rest and penetrating positions. 25

3. A delivery system according to claim 1 or claim 2, further comprising a control structure for ensuring contact of the needle with the bottom of the container while preventing penetration of the bottom of the container.

4. A delivery system according to claim 3, wherein the control structure includes a 30 force sensor for detecting engagement of the needle with the container bottom and terminating needle advance by the needle drive to avoid penetration of the container bottom by the needle. 18

5. A delivery system according to claim 4, wherein the force sensor is incorporated in the needle drive.

6. A delivery system according to any one of the preceding claims, further 5 comprising an ultrasonic sensor for detecting when the hydrogen peroxide liquid in the container drops below a predetermined level.

7. A delivery system according to claim 4, wherein the container is supported on a stand and the sensor is spring biased against the container, when the container 10 is supported on the stand.

8. A delivery system according to any one of the preceding claims, wherein the bottom of the container is conical to ensure any residual hydrogen peroxide solution collects at a lowest point of the bottom and the conical bottom of the 15 container is centered with an axis of the drainage needle for aligning a tip of the needle with the lowest point of the bottom.

9. A delivery system according to any one of the preceding claims, wherein the sealed hydrogen peroxide solution container comprises a hollow body with a 20 top end including a sealed fill and drainage opening, a side wall and a conical bottom, a stand for maintaining the container in an upright position on a flat horizontal surface prior to insertion into the cradle and a connecting arrangement for connecting the stand to the body. 25

10. A delivery system according to any one of the preceding claims, wherein the container includes an external circumferentially extending, continuous groove in the side wall of the body and the stand is cup-shaped and has at least two radially inwardly extending tabs for engagement with the groove to provide a snap fit connection of the stand to the body. 30

11. A delivery system according to claim 10, wherein each tab is a circumferentially extending flange at a top end of the stand for snap fit engagement with the groove. 19

12. A hydrogen peroxide solution container for use in a delivery system as defined according to any one of claims 1 to 11, the sealed hydrogen peroxide solution container comprising a hollow body with a top end including a sealed fill and drainage opening, a side wall and a conical bottom, a stand for maintaining the 5 container in an upright position on a flat horizontal surface prior to insertion into the cradle and a connecting arrangement for connecting the stand to the body.

13. A container according to claim 12, wherein the side wall of the body includes an external, circumferentially extending, continuous groove and the stand is cup 10 shaped and has at least a pair of radially inwardly extending tabs for engagement with the groove to provide a snap fit connection of the stand to the body.

14. A container according to claim 13, wherein each tab is a circumferentially 15 extending flange at a top end of the stand for snap fit engagement with the groove.

15. A container according to claim 14, wherein the body includes at least two external grooves and the stand includes a corresponding number of tabs 20 positioned on the stand for snap fit engagement with one of the grooves respectively.

16. A hydrogen peroxide delivery system according to claim 1, said delivery system substantially as herein described with reference to any one of the embodiments 25 of the invention illustrated in the accompanying drawings and/or examples.

17. A hydrogen peroxide solution container according to claim 12, said container substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples. 30 Dated this 2 0 th day of January 2014 Shelston IP Attorneys for: TSO3 Inc.