Decontamination airlock

Abstract

The invention relates to a decontamination chamber consisting of an enclosure equipped with a sealed loading door and a sealed unloading door, and a means for decontaminating objects deposited in said enclosure. The decontamination means comprises an ozone generator and an ozone treatment circuit including at least one suction nozzle communicating with said enclosure, a circulation pump, an ozone catalyst, an air filter having a filtration level between G4 and F9 located downstream of said ozone catalyst, and at least one nozzle for reinjecting the treated air into said enclosure; an ozone sensor immersed in said enclosure; and an automated system controlling the ozone generator based on the ozone concentration measured by said ozone sensor. Abstract Figure: Figure 2

Description

Description Title of the invention: Decontamination airlock Field of the invention The present invention relates to the field of transfer airlocks with bio-decontamination systems, sometimes called “pass-throughs” or “passboxes”. An airlock is a barrier between an area | generally a traffic area and a zone 2 to which equipment or a product sometimes needs to be transferred, without contaminating the areas between them. This barrier is physical and can also be aeraulic. The airlock consists of a sealed enclosure made up of partitions, generally with two doors. By means of an atmospheric pressure gradient, the airlock prevents any contamination of the areas to be protected. It can be equipped with decontamination means (ozone or other). State of the art Known in the prior art is patent application DE10203234A1 describing a method for decontaminating a flux box, in which ozone is generated by an ozone generator outside the flux box and then brought into the flux box. A UV lamp is mentioned as a possible type of ozone generator. Patent application EP1721684 relates to the use of a mercury vapor lamp (not just a high-pressure mercury vapor lamp) in a method for sterilizing the interior of an appliance. It turns out that by continuously cycling the air in the workspace under the effect of ozone-induced UV radiation emanating from the mercury vapor lamp, the ozone concentration can be increased to biocidal threshold values. Furthermore, this document proposes a mercury vapor lamp or a device with a mercury vapor lamp in which a light-transmitting sheathing tube of the mercury vapor lamp is made of quartz with embedded nanoparticles, which filter out ozone radiation between 180 nm and 230 nm and allow ozone decomposition radiation between 230 nm and 280 nm to pass through. Patent application EP3347127 is also known describing alpha doors for equipping a transfer chamber. In one described implementation, the assembly comprises an intermediate configuration in which the orifices are connected in a sealed manner to the spaced doors and forming a chamber between them, said chamber comprising means for introducing sterile means for decontaminating the exterior surfaces of the doors and / or their seals. Disadvantages of the prior art The prior art solutions are not suitable for transferring a product or equipment between a zone “1” and a zone “2” and vice versa, in a secure, rapid, easy manner, and guaranteeing decontamination of the product or equipment whatever its configuration. Hydrogen peroxide is frequently used to decontaminate surfaces. It is a liquid, with a larger molecular size than a gas, which makes it more difficult to penetrate the interstices of a product to be decontaminated. In addition, its production in the form of micro-condensation requires complex equipment (air compressor, Venturi nozzle, etc.). Solution provided by the invention In order to overcome these drawbacks, the present invention relates, in its most general sense, to a decontamination airlock consisting of an enclosure provided with a sealed loading door and a sealed unloading door and a means for decontaminating the objects placed in said enclosure, characterized in that said decontamination means comprises an ozone generator as well: that an ozone treatment circuit comprising at least one nozzle suction communicating with said enclosure, a circulation pump, a ozone catalyst, an air filter with a filtration level of between G4 and F9 (preferably class M5) and at least one re- nozzle injection of the treated air into said enclosure, an ozone sensor immersed in said enclosure, as well as an automaton controlling the ozone generator based on the ozone concentration measured by said ozone sensor. According to a first variant, said ozone generator consists of a system based on the corona effect. According to a second variant, said ozone generator consists of at least one Xenon lamp placed in said enclosure. According to a third variant, said ozone generator consists of a system based on a discharge in a gas emitting radiation between 100 nm and 200 nm placed in said enclosure. Preferably, said doors are interlocked in such a way that the opening of one prevents the opening of the other and in that said automaton prevents the opening of said doors when the ozone concentration measured by said ozone sensor is greater than a threshold value. Advantageously, said doors are of the inflatable seal type. Advantageously, the decontamination airlock also includes a probe humidity immersed in the enclosure, and a nebulizer opening into said enclosure. Detailed description of a non-limiting example of embodiment The present invention will be better understood on reading the following description, concerning a non-limiting example of embodiment illustrated by the appended drawings where: [Fig.1] [Fig.1] represents a perspective view of a decontamination airlock according to the invention. [Fig.2] [Fig.2] represents a schematic view of a decontamination airlock according to the invention. [Fig.3] [Fig.3] represents a schematic view of the air circuit in ozone production mode. [Fig.4] [Fig.4] represents a schematic view of the air circuit in ozone catalysis mode. [Fig.5] [Fig.5] represents the Functional Control Graph of Steps and Transitions (Grafcet) of the automaton controlling the transfer airlock. General principle of the invention The invention relates to a decontaminating transfer airlock, also called a "pass-through" or "pass box". It is intended for the transfer of materials or products between two zones with different levels of cleanliness, particle classes or biological containment. The airlock according to the invention comprises an enclosure inside which the biological decontamination of the surface of the materials inside the airlock occurs through the action of a biocidal gas: ozone (O4). Ozone is composed of three oxygen atoms. It can be produced when the energy is sufficient to break a stable molecule of dioxygen (Oz) into two unstable oxygen atoms (O-). These oxygen atoms alone seek out stable O molecules and combine to form ozone (O4). Ozone is a pale blue gas (at room temperature) with a harsh odor. The ozone molecule is unstable and tends to break apart. This is why ozone cannot be stored and must be generated in situ. Ozone is known for its biocidal properties. It is an extremely powerful oxidant, as demonstrated by comparison with chemicals such as chlorine (1.5x) and hydrogen peroxide (1.15x). It is this oxidation principle that is researched and used to destroy viruses, molds, bacteria, and spores: virucide, fungicide, bactericide, and sporicide. Literature studies show that a minimum of 2 ppm of ozone for a few minutes destroys naked or enveloped viruses, such as coronaviruses. The invention relates to the use of ozone as a biocidal agent. The surfaces of the equipment inside the airlock come into contact with ozone, which kills the microorganisms present on their surface. The contact time is adjusted according to of the desired biocidal efficacy (in decimal log). After a desired contact time, the ozone inside the airlock is destroyed using an exothermic reaction catalyst. Magnesium oxide, 2% potassium iodide, or activated carbon can be used. The air inside the airlock is drawn through a pump to pass through the catalyst before being discharged into the airlock. Ozone catalysis takes place in a closed circuit inside the enclosure. Example of the construction of a transfer airlock according to the invention Figures 1 and 2 represent a non-limiting example of an embodiment of a transfer airlock according to the invention. It comprises at least one rigid, sealed structure with 4 or 5 solid faces in a double envelope (10) defining an interior volume forming the transfer enclosure (1). Access to this enclosure (1) is via a glass loading door (11) and, on the opposite side, via a glass unloading door. The sealing of each door is ensured in a known manner by inflatable seals. In the variant illustrated in [Fig.2], ozone generation is achieved by rows of short-arc xenon discharge lamps (20) with a fused quartz envelope allowing the emitted UV radiation to pass through. The UV radiation interacts with the oxygen molecules surrounding the lamp, causing them to dissociate. Some particles then recombine into ozone O3. Alternatively, ozone generation is achieved by a corona system or by a system based on a discharge in a gas emitting radiation between 100 nm and 200 nm, installed inside the airlock. Operating cycle Initially, the loading door (11) located on the side of zone "1" is opened. This opening controls the locking of the unloading door located on the side of zone "2". The product or equipment to be transferred from zone "1" to zone "2" is introduced into the enclosure and the loading door (11) is closed. The operator commands the start of the decontamination cycle, which begins by locking the two doors and inflating the seals surrounding each of the doors. The humidity level in the treatment chamber is measured. If this level is greater than 90%, the controller (30) activates the ozone generator (20), regardless of the technology installed. If the humidity level is less than 90%, the controller activates a water nebulizer until a humidity level of 90% is obtained before triggering ozone production. Alternatively, the controller activates the ozone generator and the water nebulizer simultaneously at the start of the decontamination cycle. During the cycle, the humidity level in the chamber is maintained between 90 and 95%. The ozone content is periodically acquired by the ozone sensor (32) and processed by the circuit electronics (33) and by the automaton (31). The ozone generation mode illustrated by [Fig.3] is maintained until the ozone production reaches a threshold of approximately 30 ppm.min!. The decontamination mode can then be maintained by a time delay, or interrupted for a predetermined period, before the automaton (30) commands the switch to catalysis mode illustrated by [Fig.4]. In this mode, the ozone generation is interrupted and the automaton (30) commands the operation of the circulation pump (43) to pass part of the air contained in the enclosure (1) into the ozone catalyst (41) and into the filter (42). The CARULITE ® ozone catalyst is used to effectively destroy the ozone present in various gaseous effluents by converting the toxic ozone into oxygen. It is a mixture of manganese dioxide and copper oxide. When the exposure to ozone of the product or equipment placed in the enclosure has reached the time required to ensure decontamination, the controller (30) controls, via the supply circuit (31) of the ozone generating system (20) (for example that of the Xenon lamps), the stopping of ozone production and the activation of a residual ozone catalysis circuit in the enclosure to bring the concentration back to an acceptable level before opening the discharge door. Indeed, ozone is harmful to health and the environment. It is therefore necessary to destroy the ozone accumulated in the enclosure during the decontamination phase before opening the enclosure to the outside air. When the ozone concentration in the enclosure (1) becomes lower than 0.1 ppm, the automaton (30) stops the air circulation and releases the opening of the unloading door, which automatically causes the loading door (11) to lock.Finally, the unloading door is closed and the cycle ends, with both doors closed and unlocked. The above example concerns the feed from zone "|", but of course it is possible to make a transfer from zone "2" to zone "1". This catalysis system consists of one or more nozzles (40) penetrating in a sealed manner into the enclosure (1) to take the air contained in the enclosure (1) and make it pass through an ozone catalyst (41) which transforms the ozone into dioxygen and a filter having a filtration level between G4 and F9 and preferably of class M5 (42) which reduces the content of micrometric particles in the air treated by the catalyst (41). The treated air is then reinjected into the enclosure (1) by one or more nozzles (44) located opposite the suction nozzle(s) (40). This filter captures the particles released by the catalyst (41). The latter (42) is placed directly at the outlet of the ozone catalyst (41), and not near the reinjection nozzle. The catalyst is located outside the enclosure. A circulation pump (43) ensures air circulation in the catalysis system. An ozone sensor (32) penetrating the enclosure (1) provides an electrical signal representative of the ozone concentration in the enclosure. This signal is processed by an electronic circuit (33) to provide the controller (31) with the ozone concentration level. The automaton (31) controls the automated management of the airlock and in particular the control of the doors which are also controlled by each other. They can only open if the concentration inside the enclosure (1) is less than 0.1 ppm of Os. Alternative embodiment: generation by corona effect or by a gas discharge system Ozone is produced directly inside the airlock by transforming the oxygen in the air into ozone via an electric field between two electrodes (figures 3 and 4) or by a system based on a discharge in a gas emitting radiation between 100 nm and 200 nm which transforms the oxygen in the air into ozone (figures 3 and 4). Implementation variant: humidity management In order to improve the biocidal activity of ozone, the invention may further provide a system for controlling the humidity of the enclosure (10), comprising a humidity probe immersed in the enclosure (10), and a nebulizer producing water vapor in fine droplets from a water tank. An automaton controls this nebulizer to ensure a humidity level during the entire ozone action phase at a rate of between 90% and 95% humidity. Evolution sequences controlled by the airlock automaton. [Fig.5] represents the Functional Control Graph of Steps and Transitions (Grafcet) of the automaton controlling the transfer airlock. When one of the doors is opened (51), the other door is automatically locked (52) in the tightly closed position. The airlock (53) can then be loaded by introducing the product or equipment to be transferred from the area where the door is open to the area where the door is closed. After loading, the first door is tightly closed (54). The automaton waits for a start command (55) for the cycle. Upon receipt of this command, for example by pressing a control button, the automaton commands (56) the measurement of the humidity inside the enclosure. If the measured humidity is less than 90%, the controller controls (57) the nebulization of water in the chamber. If the measured humidity is greater than 90%, the controller (58) controls the production of ozone with a flow of 30 ppm per minute. If the humidity exceeds 95%, the controller stops nebulization. Alternatively, the controller activates the ozone generator and the water nebulizer simultaneously at the start of the decontamination cycle. In this case, the measured hygrometry and ozone production are checked in parallel from the start of the cycle. At the end of the cycle, the automaton controls the catalysis of the ozone (59) up to a rate of 0.1 ppm, then the unlocking (60) of the door on the withdrawal zone side. At the same time, the opposite door is locked (61). The airlock is then unloaded (62) towards the transfer side, and the door is closed (63).

Claims

Claims

1. Decontamination airlock consisting of an enclosure (10) equipped with a watertight loading door (11) and an unloading door waterproof and a means of decontaminating objects placed in said enclosure (10), characterized in that said decontamination means- mination includes an ozone generator as well: that an ozone treatment circuit comprising at least a suction nozzle (40) communicating with said enclosure (10), a circulation pump (43), an ozone catalyst (41), an air filter having a filtration level of between G4 and F9 (42) arranged downstream of said ozone catalyst (41), and at least one reinjection nozzle (44) for the treated air in said enclosure (10), that an ozone sensor (32) immersed in said enclosure (10), as well as an automaton controlling the ozone generator depending on the ozone concentration measured by said ozone sensor (32).

2. Decontamination airlock according to claim 1 characterized in that said ozone generator is constituted by a corona system.

3. Decontamination airlock according to claim 1 characterized in that said ozone generator is made up of a system based on a discharge in a gas emitting radiation between 100 nm and 200 nm.

4. Decontamination airlock according to claim 1 characterized in that said ozone generator consists of at least one Xenon lamp arranged in said enclosure (10).

5. Decontamination airlock according to claim 1 characterized in that said doors (10, 11) are interlocked in such a way that the opening of one prevents the opening of the other and in that said automaton prevents the opening of said doors when the concentration of ozone measured by said ozone sensor is greater than a value threshold.

6. Decontamination airlock according to claim 1 characterized in that said doors (10, 11) are of the inflatable seal type.

7. Decontamination airlock according to claim 1 characterized in that it further comprises a hygrometry probe immersed in the enclosure (10), and a nebulizer opening into said enclosure.