ES2541503B1 - Vaporizer device of a sterilizing agent and corresponding vaporization procedure - Google Patents

Abstract

Vaporizer device of a sterilizing agent and corresponding vaporization procedure. The device comprises a chamber (2), at least one steam outlet (10) of sterilizing agent, an injector device (12) of sterilizing agent and first heating means (14) arranged to heat the wall lower (4). The device is characterized in that it also comprises means for reducing the pressure (24) inside the chamber (2), and second heating means (26) for the side wall. The injector device (12) is arranged in the upper wall (6) and the sterilizing agent is injected through the injector device (12) from above by means of an injection beam projected on the side and bottom walls (4) and below of the outlet duct (10). The method according to the invention is based on the same principle of operation.

Description

VAPORIZING DEVICE OF A STERILIZATION AGENT AND CORRESPONDING VAPORIZATION PROCEDURE

DESCRIPTION

 5

 Field of the Invention

The invention is in the field of sterilization and more particularly in the field of physical or chemical sterilization by applying steam on the product to be sterilized.

 10

More particularly, the invention relates to a vaporizing device of a liquid state sterilizing agent comprising a vaporization chamber delimited by a lower wall, an upper wall and at least one side wall and at least one outlet duct of steam of sterilizing agent, an injector device of said sterilizing agent in a liquid state in said chamber, and first heating means 15 arranged to heat said lower wall.

Also, the invention relates to a vaporization process of a sterilizing agent in a liquid state comprising the steps of providing a vaporization chamber delimited by a lower wall, an upper wall and at least one side wall 20, and therefore minus a steam outlet duct of sterilizing agent, and heating said lower wall.

 State of the art

 25

Sterilization procedures from the application of sterilization agents on an article that is in the sterilization chamber of a sterilization facility are widely known in sectors such as medicine or biology. For example, sterilization procedures from steam agents such as water or hydrogen peroxide or others are very commonly used for sterilization of medical equipment such as endoscopes, surgical or laboratory instruments or the like.

In this type of procedure it is very important that the sterilization agent does not penetrate the sterilization agent in a liquid state or condenses in said chamber, since

Often these products have a high oxidizing power, which could damage the installation and also the item that must be sterilized.

On the other hand, in sterilization procedures it is very important that the quality of the sterilizing agent vapor that is introduced into the sterilizer chamber is high. In the invention, steam quality means, on the one hand, the correct vaporization of the sterilizing agent and on the other, the non-presence of contaminants.

The solution injected in a liquid state must be completely vaporized so that when it reaches the sterilization chamber of the steam sterilizer, its condensation does not occur. 10

As regards the presence of contaminants in the vapor, it directly influences the decomposition of the sterilizing agent. A decomposition of the sterilizing agent negatively and directly affects the microbicidal efficacy. This can have fatal consequences, since then the sterilization of the article is defective and article 15 allegedly sterilized becomes a vehicle of propagation of pathogenic organisms.

On the other hand, the materials used are also critical in sterilization procedures. For example, hydrogen peroxide has a high oxidizing action that is very harmful, since it reacts with most metals. Although hydrogen peroxide is not flammable by itself, its decomposition process generates large amounts of heat and oxygen.

As regards decomposition, hydrogen peroxide naturally decomposes in water and oxygen. Commercially available hydrogen peroxide is very pure and its rate of decomposition in water and oxygen is usually very low. However, if hydrogen peroxide is contaminated, for example, with salts of metals such as iron, copper, chromium, vanadium, tungsten, molybdenum, silver and platinum group metals, rapid decomposition can occur resulting in oxygen and water. Consequently, the microbiocidal effect is lost, since water and oxygen would be injected into the chamber instead of peroxide.

Rapid decomposition can also occur with extremely low levels of pollutants, that is, with few ppm (parts per million) of pollutants you can already

produce decomposition This decomposition is a chain reaction in which metal ions are oxidized and reduced successively.

It should be borne in mind that materials that are "compatible" with hydrogen peroxide can also cause rapid decomposition if their surface is not of adequate quality or has not been properly prepared.

Another of the key factors to avoid a peroxide decomposition is to avoid the modification of its pH, since the pH has a very marked effect on the rate of decomposition of this sterilizing agent. 10

 Summary of the invention

The purpose of the invention is to provide a vaporizing device of a sterilizing agent in a liquid state of the type indicated at the beginning, which allows the substance to be vaporized efficiently, providing a high quality of sterilizing agent vapor.

This purpose is achieved by means of a vaporizing device of a sterilizing agent of the type indicated at the beginning, characterized in that it also comprises means for reducing the pressure which in service are suitable for reducing the pressure inside the chamber to a lower pressure at the pressure outside the chamber, and a second heating means arranged to heat at least said at least one side wall, and because the injector device is arranged in the upper wall and configured in such a way that in operation The sterilizing agent is injectable through the injector device 25 from above by means of an injection beam projected on said at least one side wall and said bottom wall and below the outlet duct.

In the invention, special reference will be made to hydrogen peroxide as a chemical sterilizing agent. However, within the scope of the invention, the application of the invention is contemplated in other chemical sterilizers, applying a mixture of water vapor and other types of sterilizing agents such as formaldehyde or others.

Thanks to the arrangement of the heating means adjacent to the side and bottom walls simultaneously, a very uniform heat distribution is obtained inside 35

the vaporization chamber This makes it easier for the agent injected into the chamber to evaporate as soon as it comes into contact with either of the two walls on which it is injected. On the other hand, the arrangement of the injector in the upper wall avoiding that the injecting jet of the sterilization agent gets wet the outlet duct, eliminates the risk of condensation outside the vaporization chamber in the outlet duct, while in the 5 inside, the vaporization is guaranteed by immediate contact with any of the hot walls of the chamber. Also, the arrangement allows to take advantage of the effect of gravity combined with the use of a larger evaporation surface. Thus, those drops of liquid that come into contact with the side walls, in case they cannot evaporate on contact, slide down being subjected to the heat effect of the wall, which increases the time available for proper evaporation. .

Furthermore, the invention encompasses a series of preferred features that are the subject of the dependent claims and whose usefulness will be highlighted later in the detailed description of an embodiment of the invention. fifteen

As mentioned, another problem associated with chemical sterilization procedures lies in the high oxidation capacity of sterilizing agents. Thus, in order to solve this problem, preferably, the lower, upper walls and said at least one side wall are made of an aluminum and manganese alloy. twenty

On the other hand, as another one of the problems associated with chemical sterilization has been mentioned is the quality of steam. To this end, in order to maximize the quality of the steam said injector device comprises a spray nozzle for spraying said sterilizing agent during injection into the chamber. Thanks to the spray nozzle, the size of the outgoing drop of the injector is reduced. The smaller the droplet size, the easier it is for the sterilizing agent to evaporate when it contacts the walls of the vaporization chamber. Again the risk of condensation in the sterilization chamber is reduced.

It is also important to ensure the maximum amount of steam is released, preventing it from accumulating in unwanted corners of the chamber. For this, said at least one outlet duct is provided adjacent to said upper wall and flows into a manifold provided below said lower wall. This causes all rising steam to immediately exit out of the chamber and therefore the risk of condensation of steam in the chamber is minimized. 35

In another embodiment, it is provided that the first heating means are arranged adjacent to the upper part of said collector to reduce the risk of condensation of the agent at the exit of the vaporization chamber.

 5

In another preferred embodiment of the device it is provided that the second heating means extend downwards at least up to one third of the height of said collector measured from its upper part, thanks to which the risk of condensation is minimized before that the vaporized sterilization agent condenses before leaving the device and entering the sterilization chamber. 10

Finally, in another preferred embodiment, the injector device is arranged in the center of said upper wall to achieve a more homogeneous vaporization pattern throughout the vaporizer chamber.

 fifteen

The invention also relates to a vaporization process aimed at vaporization efficiency and through which a high quality sterilizing agent vapor quality is obtained.

This objective is achieved by a vaporization process of a sterilizing agent 20 in a liquid state that comprises the steps explained at the beginning and which is characterized by also comprising the steps of: heating the side wall, generating a pressure in the chamber, less than the external pressure to said chamber, and injecting said sterilizing agent from said upper wall onto said side walls and said lower wall by means of an injection beam projected onto said at least one side wall and said lower wall and 25 below said conduit output

Preferably, it has been found that when the process is applied using hydrogen peroxide as a sterilizing agent, with a concentration between 30 and 65% w / w and the chamber is heated to a temperature between 60 and 120 ° C, the 30 results are achieved optimal in the procedure.

Another relevant problem is to improve the evaporation chamber transients and the installation consumption. Therefore, preferably, in said step of generating pressure,

the pressure generated inside said chamber is less than 5 mbar, which allows reducing the temperature necessary for evaporation of peroxide.

It has also been found that preferably, when in said injection stage the sterilizing agent is injected at a pressure between 6 and 10 bar in said chamber, a higher vapor quality is achieved.

Especially preferably, the sterilizing agent is injected from the center of said upper wall.

 10

In another embodiment, the process comprises the steps of extracting the sterilizing agent through at least one outlet conduit adjacent to the upper wall and which flows into a manifold provided below said lower wall and by which it is also heats said collector.

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Likewise, the invention also encompasses other detail features illustrated in the detailed description of an embodiment of the invention and in the accompanying figures.

 Brief description of the drawings 20

Other advantages and features of the invention can be seen from the following description, in which, without any limitation, a preferred embodiment of the invention is mentioned, mentioning the accompanying drawings. The figures show:

 25

Fig. 1, a schematic longitudinal section of the vaporizing device of a sterilizing agent in the liquid state, in the rest state.

Fig. 2, a schematic longitudinal section of the vaporizer device, along a plane perpendicular to the representation plane of Figure 1, in which the vaporizer device is seen during the injection of the sterilizing agent. 30

Fig. 3, the same view as in Figure 2, in which the vaporizer device is seen during the vaporization of the sterilizing agent.

Figure 4, a schematic view of a sterilization installation with a vaporizing device of a sterilizing agent according to the invention.

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 Detailed description of an embodiment of the invention

The vaporizing device 1 of a liquid state sterilizing agent shown in the figures is basically formed by a metal housing 22 which is preferably made of an aluminum and manganese alloy. 5

The housing 22 delimits the vaporization chamber 2 through a lower wall 4, an upper wall 6 and in this case a single cylindrical side wall 8. The chamber 2 can have any shape, for example, cylindrical, parallelepipedic or other, with which there could be several side walls 10

The vaporizer device 1 also comprises an outlet duct 10 of sterilizing agent, located in the upper part of the chamber 2. Also, in the upper wall 6 there is provided an injector device 12 which is preferably placed in the center of this upper wall. 6. 15

On the other hand, the device 1 also comprises first heating means 14, but which are arranged to heat the lower wall 4, that is to say they are arranged inferiorly to said wall, and above a collector 20 which will be explained in more detail. later. twenty

The device also has means for reducing the pressure 24. The purpose of these means is to reduce the pressure inside the chamber 2 so that it is lower than that outside the chamber and preferably close to the vacuum. Thanks to this, the working temperature of the device can be significantly reduced. As can be seen in Figure 4, 25 the means for reducing the pressure 24 act simultaneously on the sterilization chamber 28 and on the vaporizer chamber 2.

In addition, a second heating means 26 are provided adjacent to the side wall 8 of the chamber 2 as heating elements arranged vertically, 30 parallel to the main axis of the chamber 2 and diametrically facing each other. One of the objectives of the invention is also the minimization of the start and stop times of the installation. Therefore, thanks to the fact that the first and second heating means 14, 26 are electrical heating resistors, a reduction of the transients is achieved during the heating of the installation. Also, this configuration achieves a distribution 35

quite homogeneous of the temperature inside the chamber 2, despite the reduced start-up times.

Each of the electrical resistors has its own temperature probe that regulates the correct working temperature. On the other hand, the vaporizer device 1 also has its own temperature probe 5 to control the internal temperature of the chamber 2. Two pressure switches are also provided which, through an electric control circuit, would stop the first and second heat input. heating means 14, 26 in case a safety limit is exceeded.

As explained, the injector device 12 is centrally arranged in the upper wall 10. In addition, its placement is selected so that in operation the injector device 12 injects the jet of sterilizing agent from above the chamber 2 forming a preferably conical beam. Thanks to this, the lateral and lower walls 8, 6 are projected as homogeneously as possible, which favors rapid vaporization of the sterilizing agent. fifteen

Next, the vaporization process according to the invention which is carried out in the vaporizer device 1 described in the preceding paragraphs, applicable to the case of hydrogen peroxide, will be explained. However, in its most general concept the process according to the invention is not limited solely to this chemical sterilization agent, since the principle of operation is valid for other chemical sterilization agents.

First, in the process according to the invention, a starting stage is provided in which both the lower wall 4 and the side wall 8 of the chamber 2 are heated by means of the first and second heating means 14, 26 Especially preferably chamber 2 is heated to a temperature between 60 and 120 ° C.

In a preferred embodiment of the invention, it is possible to start from a hydrogen peroxide with a concentration between 30 and 65% w / w. In the example described below, a hydrogen peroxide of 59% w / w concentration has been used. At this concentration a temperature of 70 ° C inside chamber 2 has been determined as especially appropriate.

Preferably, simultaneously with the heating of the chamber 2, a pressure in the chamber 2 is generated lower than the external pressure by means to reduce the pressure 24. 35

Also in this case applied to hydrogen peroxide, it has been determined that the working pressures inside the chamber 2 are less than 5 mbar, such as 1.4 mbar.

At the steady state of the device 1, the sterilizing agent is injected from the upper wall 6 at a pressure between 6 and 10 bar. By way of a non-limiting example, in the case of an amount of 1.5 ml of hydrogen peroxide for a sterilization chamber of 145 l volume, a pressure of 7 bar has been found to be optimal. The injection can be carried out through a pneumatic cylinder that introduces the predetermined amount mentioned in the vaporizer. It is also conceivable to use any equivalent injector device known in the art. Especially preferably, the injector device 12 is also a dosing device, so that the risk of poor vaporization is minimized.

The fact that such a reduced amount of peroxide is injected for a large mass of hot aluminum alloy is one of the characteristics that greatly favors vaporization. At this point, it should be noted that the aluminum and manganese housing acts very favorably on vaporization due to its high specific heat that allows heat from the first and second heating means 14, 26 to be easily transferred to the sterilizing agent that It must be vaporized.

 twenty

As can be seen in Figure 2, with the injector device 12 a conical shaped beam is projected that wets the side walls 8 and bottom 4. However, as can be seen, the beam of sterilizing agent 18 protruding from the injector device 12 contacts the side wall 8 at a point sufficiently far from the upper wall 6 and which is located below the outlet duct 10 to avoid any risk of sterilizing agent leaving in a liquid state. It has also been found that another of the factors that favor a correct vaporization is the size of the outlet duct of the injector device 12. For the aforementioned injection quantities, a circular cross-section duct with a diameter of between 0.5 is very favorable and 3 mm, for example, 1 mm.

 30

Optionally, the injector device 12 may have a spray nozzle for spraying the sterilizing agent 18. This reduces the drop diameter and again increases the efficiency of the vaporizer device 1 and the quality of the steam obtained.

In Figure 3, it can be seen that after contact of the sterilizing agent 18 with the lower walls 4 and side 8, the hydrogen peroxide is automatically vaporized, which significantly increases the pressure inside the chamber 2. Due to this and already In the vapor phase, the sterilizing agent exits through the outlet ducts 10 adjacent to the upper wall. Then, through the discharge ducts 30 which extend downwardly 5, it flows into a collector 20 provided below the lower wall 4 and the first heating means 14. At this point, the perfectly vaporized hydrogen peroxide leaves the manifold 20 in the direction of the sterilizer chamber not shown in the figures. Also at this point it can be seen that because the first heating means 14 are adjacent to the upper part of the collector 20 because the second heating means 10 extend downwards to one third of the height of said measured collector 20 from its upper part the risk of condensation is reduced again before entering the sterilization chamber 28, since the temperature is kept substantially constant throughout the steam path.

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The embodiment described so far represents a non-limiting example, so that the person skilled in the art will understand that beyond the example shown, multiple combinations between the claimed features are possible within the scope of the invention.

Claims (13)

1.- Vaporizer device (1) of a sterilizing agent in a liquid state comprising [a] a vaporization chamber (2) delimited by a lower wall (4), an upper wall 5 (6) and at least one side wall (8) and at least one outlet duct (10) of steam of sterilizing agent, [b] an injector device (12) of said sterilizing agent in a liquid state in said chamber (2), and [c] first heating means (14) arranged to heat said lower wall 10 (4), characterized in that it further comprises [d] means for reducing the pressure (24) which in service are capable of reducing the pressure inside said chamber (2) to a pressure lower than the pressure outside said chamber (2), and [e] a second heating means (26) arranged for heating, at least 15 said at least one side wall, and why [f] said injector device (12) is disposed in said upper wall (6) and configured such that in operation said sterilizing agent is injectable through said injector device (12) from above by means of an injection beam projected onto said at least one side wall (8) and said bottom wall 20 (4) and below said outlet duct (10). 2. Device according to claim 1, characterized in that said lower, upper walls (4, 6) and said at least one side wall (8) are made of an aluminum and manganese alloy. 25 3. Device according to claim 1 or 2, characterized in that said injector device (12) comprises a spray nozzle (16) for spraying said sterilizing agent during injection into said chamber (2).  30 4. Device according to any of claims 1 to 3, characterized in that said at least one outlet duct (10) is provided adjacent to said upper wall (6) and flows into a manifold (20) provided below said bottom wall (4). 5. Device according to claim 4, characterized in that first heating means (14) are arranged adjacent to the upper part of said collector (20). 6. Device according to claim 4 or 5, characterized in that said second heating means (26) extend downwards at least one third of the height of said collector (20) measured from its upper part. 7. Device according to any of claims 1 to 6, characterized in that said injector device (12) is arranged in the center of said upper wall (6).  10 8.- Method of vaporization of a sterilizing agent in a liquid state comprising the steps of: [a] providing a vaporization chamber (2) delimited by a lower wall (4), an upper wall (6) and at least one side wall (8), and at least one steam outlet (10) of sterilizing agent, and 15 [b] heating said lower wall (4), characterized in that it also includes the stages of: [c] heating said side wall (8), [d] generate a pressure in said chamber (2), lower than the pressure outside said chamber (2), and 20 [e] injecting said sterilizing agent from said upper wall (6) onto said side walls and said lower wall (4) by an injection beam projected onto said at least one side wall (8) and said lower wall (4) and below said outlet duct (10).  25 9. Method of vaporization of a sterilizing agent in a liquid state according to claim 8, characterized in that said sterilizing agent is hydrogen peroxide with a concentration comprised between 30 and 65% w / w and said chamber (2) is heated at a temperature between 60 and 120 ° C.  30 10. Method of vaporization of a sterilizing agent in a liquid state according to claim 8 or 9, characterized in that in said step of generating pressure, the pressure generated inside said chamber (2) is less than 5 mbar. 11. Method of vaporization of a sterilizing agent in a liquid state according to any of claims 8 to 10, characterized in that in said injection stage the sterilizing agent is injected at a pressure between 6 and 10 bar in said chamber.  5 12. Method of vaporization of a sterilizing agent in a liquid state according to any of claims 8 to 11, characterized in that said sterilizing agent is injected from the center of said upper wall (6). 13. Method of vaporization of a sterilizing agent in a liquid state according to any one of claims 8 to 12, characterized in that it comprises the steps of extracting said sterilizing agent through at least one adjacent outlet duct (10) to said upper wall (6) and which flows into a collector (20) provided below said lower wall (4) and by which said collector (20) is also heated.   fifteen