An ozone decontamination plant and a method for decontaminating kernels

Abstract

Disclosed is an ozone decontamination plant (1) for decontamination of kernels (2). The decontamination plant (1) comprises an ozone production unit (3) arranged to produce ozone and a decontamination chamber (4). The decontamination chamber (4) comprises at least one upper kernel inlet (5) through which the kernels (2) enter the decontamination chamber (4), wherein the at least one upper kernel inlet (5) is arranged at a. top of the decontamination chamber (4). The decontamination chamber (4) also comprises at least one lower kernel outlet (6) through which the kernels (2) leave the decontamination chamber (4), wherein the at least one lower kernel outlet (6) is arranged at a bottom of the decontamination chamber (4). Furthermore, the decontamination chamber (4) comprises one or more chamber walls (7, 8) extending between the top and the bottom of the decontamination chamber (4) and one or more first level ozone feeding means (9) arranged at a first vertical level (10) inside the decontamination chamber (4), wherein the one or more first level ozone feeding means (9) are fluidly connected to the ozone production unit (3), wherein the one or more first level ozone feeding means (9) are extending from a chamber wall (7) of the one or more chamber walls (7, 8) to an opposite chamber wall (8). Further, the decontamination chamber (4) comprises one or more gas extraction means (11) arranged at a second vertical level (12) inside the decontamination chamber (4), wherein the one or more gas extraction means (11) are extending from the chamber wall (7) of the one or more chamber walls (7, 8) to the opposite chamber wall (8), and wherein the first vertical level (10) is vertically higher than the second vertical level (12). A method for decontaminating kernels (2) is also disclosed.

Description

[0001] AN OZONE DECONTAMINATION PLANT AND A METHOD FOR DECONTAMINATING

[0002] KERNELS

[0003] Background of the invention

[0004] The invention relates to an ozone decontamination plant for decontamination of kernels, wherein the decontamination plant comprises an ozone production unit arranged to produce ozone and a decontamination chamber. The invention also relates to a method for decontaminating kernels.

[0005] Description of the Related Art

[0006] It is known to use ozone for decontamination to protect and preserve food and feed so that losses are avoided, in that ozone kills substantially all microorganisms like insects, mites, bacteria, virus and other protozoa.

[0007] Thus, from the US patent US 9,560,860 B2 it is known to form an apparatus for decontaminating grain with ozone, where the apparatus includes a grain inlet, a decontamination chamber that includes a plurality of baffles and a plurality of ozone ports, and a grain outlet at the bottom of the chamber through which the grain and unused ozone is extracted from the chamber. However, this design makes it difficult to ensure that all grain is treated sufficiently and since ozone is toxic it is not optimal to remove unused ozone from the chamber along with the grains.

[0008] Thus, from the US patent US 6,171,625 Bl another system for the decontamination of agricultural products by means of ozone exposure is disclosed, in which the ozone is supplied to a chamber through inlet ports arranged in the chamber walls and / or through an ozone delivery manifold arranged in the middle of the chamber. Gas - e.g. containing excess ozone --- is extracted through exit ports arranged in the chamber walls at which ozone sensors are also arranged. However, ozone is heavier than air and will therefore have a tendency to travel downwards and it is therefore very difficult to ensure sufficient and even exposure of ozone to all material in the chamber. Furthermore, this system is complex and expensive.

[0009] An object of the invention is therefore to provide for a more cost-efficient ozone decontamination technique.

[0010] The invention

[0011] The invention provides for an ozone decontamination plant for decontamination of kernels. The decontamination plant comprises an ozone production unit arranged to produce ozone and a decontamination chamber. The decontamination chamber comprises at least one upper kernel inlet through which the kernels enter the decontamination chamber, wherein the at least one upper kernel inlet is arranged at a top of the decontamination chamber. The decontamination chamber also comprises at least one lower kernel outlet through which the kernels leave the decontamination chamber, wherein the at least one lower kernel outlet is arranged at a bottom of the decontamination chamber. Furthermore, the decontamination chamber comprises one or more chamber walls extending between the top and the bottom of the decontamination chamber and one or more first level ozone feeding means arranged at a first vertical level inside the decontamination chamber, wherein the one or more first level ozone feeding means are fluidly connected to the ozone production unit, wherein the one or more first level ozone feeding means are extending from a chamber wall of the one or more chamber walls to an opposite chamber wall. Further, the decontamination chamber comprises one or more gas extraction means arranged at a second vertical level inside the decontamination chamber, wherein the one or more gas extraction means are extending from the chamber wall of the one or more chamber walls to the opposite chamber wall, and wherein the first vertical level is vertically higher than the second vertical level.

[0012] Arranging both ozone feeding means and gas extraction means inside the chamber so that the both extend all the way across the chamber is advantageous in that this increase the chance of a more uniform ozone exposure of the kernels while at the same time ensuring that the kernels - traveling down through the chamber - is stirred and mixed up to ensure better and more uniform exposure to the ozone. Furthermore, extracting the gas -- e.g. containing excess ozone - inside the chamber and before the kernels leave the chamber through the lower kernel outlet is advantageous in that this reduces the risk of ozone leaving the chamber with the kernels and thereby reduces ozone usage and forms a safer ozone decontamination plant. Also, arranging the ozone feeding means above the gas extraction means entails that the ozone will travel downwards along with the kernels and thereby ensure a better and more controlled exposure to the ozone.

[0013] Even further, making the decontamination plant comprises an ozone production unit is advantageous in that this eliminates the ozone waste associated with longer periods of ozone storage.

[0014] It should be emphasised that by the term “decontamination'’'’ is understood the removal - partly or fully - of pollution in the form of one or more toxins or biologic contaminants. I.e., the term includes fully or partly removal of toxins like Mycotoxins, Fumonisins, Pesticides, etc.; and / or biologic contaminants like: Insects, Bacteria, Fungus, Mites, Viruses and / or any other microorganism / protozoa and / or toxic chemicals - either natural or manmade.

[0015] Furthermore, in this context the term “kernel” is to be understood as any kind of pip, seed, germ, bean, nut or grain and the like. I.e., the term includes any kind of grain or seed from wheat, rice, barley, oat, rape, sunflower, soybean, grass, canola, any cereals, any nuts, beans - such as coffee beans, coco beans or other - or any combination thereof.

[0016] Further, in this context the term “ozone feeding means” is to be understood as any kind of ozone feeder arranged to feed ozone into the decontamination chamber. I.e., the term includes any kind of inlet opening, nozzle, channel, duct or other e.g., combined with a pump, a fan, a valve or other or any combination thereof.

[0017] Further, in this context the term “gas extraction means" is to be understood as any kind of gas extractor arranged to extract gas from the decontamination chamber. I.e., the term includes any kind of outlet opening, nozzle, channel, duct or other e.g., combined with a pump, a fan, a valve or other or any combinati on thereof.

[0018] Also, it should be noted that any reference to orientation - such as up, down, top, bottom, underneath, over, below, side etc. - throughout this document should be understood as the orientation when the ozone decontamination plant is operating normally as it is intended during normal use.

[0019] In an aspect of the invention, the decontamination chamber further comprises one or more third level ozone feeding means arranged at a third vertical level inside the decontamination chamber, wherein the one or more third level ozone feeding means are fluidly connected to the ozone production unit, wherein the one or more third level ozone feeding means are extending from a chamber wall of the one or more chamber walls to an opposite chamber wall, and wherein the third vertical level is vertically below' the second vertical level.

[0020] Arranging third level ozone feeding means below' the gas extraction means is advantageous in that by also creating a flow of ozone upwards and thereby opposite the flow' of kernels down through the chamber, the kernels are exposed to ozone flowing both upwards and downwards whereby a better and more uniform ozone exposure of the kernels is ensured.

[0021] In an aspect of the invention, the one or more first level ozone feeding means comprises first level flow' control means arranged to control the flow' of ozone into the decontamination chamber at the first vertical level and wherein the one or more third level ozone feeding means comprises third level flow control means arranged to control the flow of ozone into the decontamination chamber at the third level.

[0022] Not all types of kernels have to be treated in the same way and it is therefore advantageous to provide the ozone feeding means with flow control means arranged to control the flow of ozone into the decontamination chamber to adjust the ozone usage to the specific task. Furthermore, providing the ozone feeding means with flow control means also enables that the amount of ozone being guided into the chamber can be adjusted in relation to the traveling speed of the kernels down through the chamber, to ensure sufficient exposure of ozone to the kernel and thereby form a more efficient and versatile ozone decontamination plant.

[0023] In this context the term ‘"flow control means'" is to be understood as any kind of flow controller capable of controlling the flow of ozone into the decontamination chamber by means of the ozone feeding means. I.e., the term includes any kind of valve, pump, regulator or other controlled manually or automatically e.g., by a Programmable Logic Controller (PLC), hardwired logical circuit, computer or other.

[0024] In an aspect of the invention, the one or more first level ozone feeding means arranged at a first vertical level, the one or more gas extraction means arranged at a second vertical level and the one or more third level ozone feeding means arranged at a third vertical level together forms a first decontamination zone inside the decontamination chamber, wherein the decontamination chamber further comprises at least one further decontamination zone inside the decontamination chamber, wherein the at least one further decontamination zone also comprises one or more first level ozone feeding means arranged at a first vertical level, one or more gas extraction means arranged at a second vertical level and the one or more third level ozone feeding means arranged at a third vertical level and wherein the at least one further decontamination zone is arranged below the first decontamination zone. Arranging ozone feeding means and gas extraction means in more than one vertically displaced decontamination zones ensures a higher degree of ozone exposure to the kernels as they travel down through the chamber whereby the travel speed of the kernels can be increased and the capacity and / or efficiency of the ozone decontamination plant thereby is increased and / or the capacity of the ozone decontamination plant can be adjusted by engaging more or less decontamination zones.

[0025] In an aspect of the invention, the ozone feeding means and the gas extraction means comprises baffles each comprising an upward facing apex between two downward sloping sides as seen from the chamber wall towards the opposite chamber wall.

[0026] Providing the ozone feeding means and the gas extraction means with baffles ensures that the kernels are better stirred and mixed up as they travel down through the chamber thereby ensuring better and more uniform exposure to the ozone. And forming the baffles by means of downward sloping sides on either side of an upward facing apex ensures that kernels wi 11 be deflected by the baffles and thereby not build up on top of the baffles. Furthermore, this baffle design ensures that a natural channel is formed underneath the baffle ensuring that ozone guided in under the baffle can travel unhindered throughout the full length of the baffle at the ozone feeding means and gas can be extracted throughout the full length of the baffle at the gas extraction means thereby forming simple and efficient ozone feeding means and gas extraction means.

[0027] In an aspect of the invention, the ozone feeding means comprises an ozone inlet arranged below7the apex of the baffles and wherein the gas extraction means comprises a gas outlet arranged below7the apex of the baffles.

[0028] Unlike fluids kernels cannot move upwards and fill the void formed below the apex of the baffles and it is therefore advantageous to place the ozone inlet and the gas outlet, respectively, just below the apex of the baffles so that the naturally formed channels underneath the baffles can be used for distributing the ozone throughout the full length of the baffle at the ozone feeding means and for extracting gas throughout the full length of the baffle at the gas extraction means.

[0029] In an aspect of the invention, the ozone decontamination plant further comprises ozone level detection means arranged to detect an ozone level at the one or more gas extraction means and control means arranged to control the gas extraction speed at the one or more gas extraction means in response to input from the ozone level detection means.

[0030] Arranging ozone level detection means at the gas extraction means enables that the ozone usage can be better controlled and better optimized in relation to the specific task, in that the gas extraction speed of the gas extraction means can be controlled better in response to input from the ozone level detection means.

[0031] In this context the terra “ozone level detection means’'’ is to be understood as any kind of ozone level detector capable of detecting the ozone level at the gas extraction means. I.e., the term comprises any kind of ozone meter, ozone sensor, ozone monitor or other including an electrochemical sensor, ultraviolet absorption technology or another ozone detection technology.

[0032] In this context the term “control means ' is to be understood as any kind of controller capable of control the gas extraction speed at the gas extraction means in response to input from the ozone level detection means. I.e., the term comprises any kind of Programmable Logic Controller (PLC), hardwired logical circuit, computer or other or any combination thereof.

[0033] In an aspect of the invention, the decontamination chamber further comprises two or more kernel moving means arranged substantially side by side across the bottom of the decontamination chamber above the at ieast one lower kernel outlet, wherein the two or more kernel moving means are arranged to actively move the kernels towards the lower kernel outlet.

[0034] Arranging two or more kernel moving means across a bottom of the decontamination chamber to actively move the kernels towards the one or more lower kernel outlets is advantageous in that this ensures a more uniform travel of the kernels down through the chamber over the entire horizontal cross section of the chamber, thereby increasing the chance of all kernels being uniformly exposed to ozone during the travel down through the chamber.

[0035] In this context the term “kernel moving means ' is to be understood as any kind of kernel mover capable of actively moving the kernels towards the lower kernel outlet. I.e., the term includes any kind of rotating roller, trundle, barrel or other e.g., comprising lamellas, brushes or another type of guide or carrier; the term includes any kind of conveyer - e.g., belt, screw, chain or other, any kind of rotating wheel arrangement or other or any combination thereof.

[0036] Furthermore, the invention provides for a method for decontaminating kernels. The method comprises the steps of:

[0037] • guiding kernels into a decontamination chamber through at least one upper kernel inlet arranged at a top of the decontamination chamber,

[0038] • removing kernels from the decontamination chamber through at least one lower kernel outlet arranged at a bottom of the decontamination chamber,

[0039] • guiding ozone from an ozone production unit into the decontamination chamber by means of one or more first level ozone feeding means arranged at a first vertical level inside the decontamination chamber, wherein the one or more first level ozone feeding means are fluidly connected to the ozone production unit producing the ozone, wherein the one or more first level ozone feeding means are extending from a chamber wall of the one or more chamber walls to an opposite chamber wall, wherein the ozone is guided into the decontamination chamber while the kernels are traveling down through the decontamination chamber from the at least one upper kernel inlet to the at least one lower kernel outlet,

[0040] * extracting gas from the decontamination chamber by means of one or more gas extraction means arranged at a second vertical level inside the decontamination chamber, wherein the one or more gas extraction means are extending from the chamber wall of the one or more chamber walls to the opposite chamber walk wherein the first vertical level is vertically higher than the second vertical level and wherein the gas is extracted from the decontamination chamber while the kernels are traveling down through the decontamination chamber from the upper kernel inlet to the lower kernel outlet and while the ozone is guided from an ozone production unit into the decontamination chamber by means of the one or more first level ozone feeding means.

[0041] Extracting gas from the decontamination chamber by means of gas extraction means arranged inside the decontamination chamber vertically below the ozone feeding means arranged inside the decontamination chamber to guide ozone into the chamber and making the gas extraction means and the ozone feeding means extend all the way across the chamber is advantageous, in that a more uniform and efficient decontamination of the kernels traveling down through the chamber is hereby ensured.

[0042] In an aspect of the invention, a gas extraction speed of the one or more gas extraction means is controlled in response to an ozone level at the one or more gas extraction means. Controlling the gas extraction speed in response to the ozone level at the extraction means is advantageous in that a more cost-efficient operation of the ozone decontamination plant hereby is enabled.

[0043] In an aspect of the invention, the humidity of the ozone-containing gas stream entering the chamber by means of the ozone feeding means is adjusted before the ozone-containing gas stream enters the chamber.

[0044] Adjusting the humidity of the ozone before it enters the chamber is advantageous in that it hereby is possible to control the humidity in the chamber within a desired range.

[0045] In an aspect of the invention, the humidity of the ozone-containing gas stream is at least 50%, preferably at least 60% and most preferred at least 70%.

[0046] The ozone is a more efficient decontamination agent in relation to certain mycotoxins if the humidity during the decontamination process is above a certain level. Thus, the present humidity levels provide a more efficient decontamination process.

[0047] In an aspect of the invention, the method is for decontaminating kernels by way of an ozone decontamination plant according to any of the previously discussed ozone decontam inati on pl an ts .

[0048] Hereby is achieved an advantageous embodiment of the invention.

[0049] Figures

[0050] The invention will be described in the following with reference to the figures in which. fig. 1 illustrates a cross section through an ozone decontamination plant, as seen from the side, fig. 2 illustrates a cross section through a decontamination chamber of an ozone decontamination plant, as seen from the front, and fig. 3 illustrates a baffle, as seen in perspective.

[0051] Detailed description of related art

[0052] Fig. 1 illustrates a cross section through an ozone decontamination plant 1, as seen from the side and fig. 2 illustrates a cross section through the decontamination chamber 4 of the ozone decontamination plant 1 illustrated in fig. 1, as seen from the frontin this embodiment the ozone decontamination plant 1 comprises an ozone production unit 3 (see fig. I) arranged to produce the ozone to be used in the decontamination process. Ozone is very difficult to stored and transported like other industrial gases because it quickly decays into diatomic oxygen, and it is therefore advantageous to produce the ozone to be used on site. In this embodiment the ozone production unit 3 produces ozone by means of the silent electric discharge process, otherwise known as coronal discharge, wherein air or oxygen is passed through an intense, high frequency alternating current electric field. However, in another embodiment the ozone production unit 3 could also or instead comprise vacuumultraviolet (VUV) ozone generators, electrolytic ozone generators (EOG) or any other kind of ozone generator or any combination thereof.

[0053] In this embodiment the ozone decontamination plant 1 further comprises a decontamination chamber 4 which includes upper kernel inlets 5 arranged at the top of the decontamination chamber 4 and through which kernels 2 are introduced into the decontamination chamber 4. In this embodiment several upper kernel iniets 5 are distributed across the top of the decontamination chamber 4 to form a substantially level top layer of kernels 2 in the top part, of the chamber 4 but in another embodiment the decontamination chamber 4 could be provided with more or less upper kernel inlets 5 depending on the specific chamber design, the specific task or other. In fig. 1 the decontamination chamber 4 is disclosed without kernels 2 and in fig. 2 the decontamination chamber 4 is shown substantially full of kernels located in the decontamination chamber 4 as it would be during normal operation of the ozone decontamination plant 1.

[0054] In this embodiment a lower kernel outlet 6 is arranged at the bottom of the decontamination chamber 4 through which the kernels 2 leave the decontamination chamber 4. In this embodiment a screw conveyor 27 is arranged at the bottom of the chamber 4 to draw the kernels 2 out through the lower kernel outlet 6 in a controlled manner but in another embodiment the kernels 2 could leave through the lower kernel outlet 6 by means of gravity, by means of another conveyer type or other or any combination thereof. In this embodiment the decontamination chamber 4 is provided with only one lower kernel outlet 6 but in another embodiment the decontamination chamber 4 could be provided with more lower kernel outlets 6 - such as two, three, four, six or even more.

[0055] In this embodiment the decontamination chamber 4 further comprises four kernel moving means 26 arranged substantially side by side across the bottom of the decontamination chamber 4 above the lower kernel outlet 6. The kernel moving means 26 are in this embodiment formed as lamella rollers driven by a kernel moving motor 28 arranged to rotate the lamella rollers so that the four kernel moving means 26 will actively move the kernels 2 towards the lower kernel outlets 6 and thereby create a uniform flow of the kernels 2 across the entire horizontal cross section of the decontamination chamber 4. However, in another embodiment the decontamination chamber 4 could comprise more kernel moving means 26 - such as six, eight, ten or even more --- or fewer kernel moving means 26 - such as three, two or even only one - depending on the type and design of the kernel moving means 26, the size of the decontamination chamber 4, the type of kernels or other. In another embodiment a lower kernel outlet 6 could be formed below7each kernel moving means 26 so that the number of lower kernel outlets 6 would correspond with the number of kernels moving means 26.

[0056] In this embodiment the decontamination chamber 4 comprises two decontamination zones 17, 18 in the form of a first decontamination zone 17 arranged vertically above a further decontamination zone 18. However, in another embodiment the decontamination chamber 4 could comprise only one decontamination zone 17 or the decontamination chamber 4 could comprises more further decontamination zones 18 - such as two, three, four, five or even more - e.g., depending on the capacity requirement, the specific kernel type, the chamber design or other.

[0057] In this embodiment each of the decontamination zones 17, 18 comprise six first level ozone feeding means 9 arranged side by side across the decontamination chamber 4 at a first vertical level 10 vertically above six gas extraction means 11 arranged side by side across the decontamination chamber 4 at a second vertical level 12. The first level ozone feeding means 9 and the gas extraction means 11 are extending from one chamber wall 7 all the way across the decontamination chamber 4 to an opposite chamber wall 8, and the ozone feeding means 9 are fluidly connected to the ozone production unit 3 while the gas extraction means 11 are connected to a pump 29 by means of which gas is extracted from the decontamination chamber 4 through the gas extraction means 11.

[0058] In this embodiment each of the decontamination zones 17, 18 further comprise six third level ozone feeding means 13 arranged side by side across the decontamination chamber 4 at a third vertical level 14 vertically below7the six gas extraction means 1 1. The third level ozone feeding means 13 are also extending from one chamber wall 7 all the way across the decontamination chamber 4 to the opposite chamber wall 8, and the third level ozone feeding means 13 are also fluidly connected to the ozone production unit 3.

[0059] In this embodiment the decontamination zones 17, 18 each comprises six first level ozone feeding means 9, six gas extraction means 11 and six third level ozone feeding means 13 arranged to extend parallel vertically above or below each other. However, in another embodiment one or more of the decontamination zone 17, 18 could comprise fewer first level ozone feeding means 9, gas extraction means 11 and / or third level ozone feeding means 13 - such as two, three, five --- and / or more - such as eight, ten, twelve or even more - e.g., depending on the size of the first level ozone feeding means 9, the gas extraction means 11 and / or the third level ozone feeding means 13, depending on the size of the decontamination chamber 4, the specific kernel type or other. And in another embodiment one or more of the decontamination zones 17, 18 could comprise more ozone feeding means 9, 13 arranged outside the first vertical level and / or third vertical level and / or one or more of the decontamination zones 17, 18 could comprise more gas extraction means 11 arranged outside the second vertical level.

[0060] In this embodiment the decontamination chamber 4 is formed as a high square tank having four walls 7, 8 extending between the top and the bottom of the decontamination chamber 4. However, in another embodiment the decontamination chamber 4 could be formed differently e.g., by having another number of walls, such as one (if the chamber had a circular or oval cross section), six, eight or more and / or the chamber 4 could have another shape, such as rectangular, polygonal or other.

[0061] In this embodiment the first level ozone feeding means 9 comprises first level flow control means 15 in the form of valves arranged to control the flow of ozone into the decontamination chamber 4 at the first vertical level 10 and the third level ozone feeding means 13 comprises third level flow control means 16 also in the form of valves arranged to control the flow of ozone into the decontamination chamber 4 at the third vertical level 14.

[0062] In this embodiment the ozone decontamination plant 1 further comprises ozone level detection means 24 arranged to detect an ozone level at the gas extraction means 11 and control means 25 arranged to control the pump 29 to thereby control the gas extraction speed at the gas extraction means 11 in response to input from the ozone level detection means 24. In this embodiment the ozone level detection means 24 are arranged at one end of the gas extraction means 11 but in another embodiment the ozone level detection means 24 could also or instead be located inside the gas extraction means 11, at the other end of the gas extraction means 11, near, in or at the gas outlet 23 or other.

[0063] In this embodiment the control means 25 are also arranged to control the status of the first level flow control means 15, the third level flow7control means 16, and the operation of the ozone production unit 3 but in another embodiment one or more of these features could comprise their own separate control means e.g., exchanging data with the other control means. In another embodiment the decontamination chamber 4 could be also provided with further ozone level detection means 24 arranged at other locations in the decontamination chamber 4 to monitor the operation and / or efficiency of the decontamination process and / or the decontamination chamber 4 could be provided with further sensors - such as humidity sensors, temperature sensors, flow sensors or other - e.g., enabling that the operation of the decontaminating plant 1 could be controlled based on further input from one or more of these further sensors.

[0064] In this embodiment the decontaminating plant 1 is operated by guiding kernels 2 into the decontamination chamber 4 through the upper kernel inlet 5 while removing kernels 2 from the decontamination chamber 4 through the lower kernel outlet 6 to generate a continuous flow7of kernels 2 down through the decontamination chamber 4, However, in another embodiment the kernels 2 could be fed to the chamber 4 in steps in response to a level detection in the decontamination chamber 4 and / or the kernels 2 could be removed from the decontamination chamber 4 in response to a level detection in the decontamination chamber 4, in response to decontamination detection of the kernels 2 or other.

[0065] In this embodiment ozone is guided from the ozone production unit 3 into the decontamination chamber 4 by means of the first level ozone feeding means 9 while the kernels 2 are traveling down through the decontamination chamber 4 and while gas is extracted from the decontamination chamber 4 by means of the gas extraction means 11 arranged at below' the first level ozone feeding means 9, so that the ozone is traveling from the first level ozone feeding means 9 down towards the gas extraction means 11 in the same flow direction as the kernels 2. Ideally the kernels 2 are fully decontaminated and the ozone is fully used when the kernels 2 reach the gas extraction means 11.

[0066] However, in an embodiment ozone is also guided from the ozone production unit 3 into the decontamination chamber 4 by means of third level ozone feeding means 13 arranged below the gas extraction means 11 to form a flow of ozone from the third level ozone feeding means 13 and up towards the gas extraction means 11 so that the ozone introduced by means of the third level ozone feeding means 13 is traveling in an opposite flow direction in relation to the flow direction of the kernels 2.

[0067] In an embodiment the gas extraction speed of the one or more gas extraction means 11 is controlled in response to an ozone level at the gas extraction means 11. However, in another embodiment the amount of ozone introduced into the decontamination chamber 4 by means of first level ozone feeding means 9 and / or the third level ozone feeding means 13 is also or instead controlled in response to the ozone level at the gas extraction means 11. In an embodiment the operation of the decontaminating plant 1 also comprises guiding the kernels 2 down through one or more further decontamination zones 18 arranged below the first decontamination zone 17 formed by the first level ozone feeding means 9, the gas extraction means 11 and the optional third level ozone feeding means 13, wherein the one or more further decontamination zones 18 comprise the same features and are operated in the same way as the above described first decontamination zone 17 and / or one or more of the one or more further decontamination zones 18 comprise different features and / or are operated in a different way than the above described first decontamination zone 17.

[0068] Fig. 3 illustrates a baffle 19, as seen in perspective.

[0069] In the embodiments disclosed in figs. 1 and 2 the ozone feeding means 9, 13 and the gas extraction means 11 comprises baffles 19 formed as illustrated in fig. 3 - i.e., substantially as angle iron with the apex 20 facing upwards, and the ozone feeding means 9, 13 comprise an ozone inlet 22 arranged below the apex 20 of the baffl es 19 and the gas extraction means 1 1 comprise a gas outlet 23 arranged below the apex 20 of the baffles 19 so that the baffles 19 forms a channel all the way across the decontamination chamber 4 through which the ozone may be distributed or gas may be extracted, respectively (as seen in fig. 2).

[0070] However, in another embodiment the apex 20 of the baffles 20 could be rounded --- i.e. provided with a radius, one or more of the baffles 20 could be formed as semicircles, as inverted U’s, as angle iron with curving downwards sloping side, one or more baffles could comprise more than one bend or the baffles could be formed in a multitude of other ways where the baffles 19 would have an upward facing apex 20 between two downwards sloping sides 21 during normal use of the ozone decontamination plant 1. However, in another embodiment the ozone feeding means 9, 13 and / or the gas extraction means 11 could also or instead comprise perforated tubes, pipes comprising nozzles, ducts comprising sieves or other or any combination thereof.

[0071] The invention has been exemplified above with reference to specific examples of decontamination chambers 4, ozone feeding means 9, 13, gas extraction means 11 and other. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims.

[0072] List

[0073] 1. Ozone decontamination plant

[0074] 2. Kernels

[0075] 3. Ozone production unit

[0076] 4. Decontamination chamber

[0077] 5. Upper kernel inlet

[0078] 6. Lower kernel outlet

[0079] 7. Chamber wall

[0080] 8. Opposite chamber wall

[0081] 9. First level ozone feeding means

[0082] 10. First vertical level

[0083] 1 1. Gas extraction means

[0084] 12. Second vertical 1 evel

[0085] 13. Third level ozone feeding means

[0086] 14. Third vertical level

[0087] 15. First level flow control means

[0088] 16. Third level flow control means

[0089] 17. First decontamination zone

[0090] 18. Further decontaminati on zone

[0091] 19. Baffle

[0092] 20. Apex of baffle

[0093] 21. Downward sloping side of baffle

[0094] 22. Ozone inlet

[0095] 23. Gas outlet

[0096] 24. Ozone level detection means

[0097] 25. Control means

[0098] 26. Kernel moving means

[0099] 27. Screw conveyer

[0100] 28. Kernel moving motor

[0101] 29. Pump

Claims

Claims1. An ozone decontamination plant (1) for decontamination of kernels (2), wherein said decontamination plant (I) comprises. an ozone production unit (3) arranged to produce ozone, and. a decontamination chamber (4) comprising. o at least one upper kernel inlet (5) through which said kernels (2) enter said decontamination chamber (4), wherein said at least one upper kernel inlet (5) is arranged at a top of said decontamination chamber (4), o at least one lower kernel outlet (6) through which said kernels (2) leave said decontamination chamber (4), wherein said at least one lower kernel outlet (6) is arranged at a bottom of said decontamination chamber (4), o one or more chamber walls (7, 8) extending between said top and said bottom of said decontamination chamber (4), o one or more first level ozone feeding means (9) arranged at a first vertical level (10) inside said decontamination chamber (4), wherein said one or more first level ozone feeding means (9) are fluidly connected to said ozone production unit (3), wherein said one or more first level ozone feeding means (9) are extending from a chamber wal l (7) of said one or more chamber walls (7, 8) to an opposite chamber wall (8), and o one or more gas extraction means (11) arranged at a second vertical level (12) inside said decontamination chamber (4), wherein said one or more gas extraction means (11) are extending from said chamber wall (7) of said one or more chamber walls (7, 8) to said oppositechamber wall (8), and wherein said first vertical level (10) is vertically higher than said second vertical level.

2. An ozone decontamination plant (1) according to claim 1, wherein said decontamination chamber (4) further comprises one or more third level ozone feeding means (13) arranged at a third vertical level (14) inside said decontamination chamber (4), wherein said one or more third level ozone feeding means (13) are fluidly connected to said ozone production unit (3), wherein said one or more third level ozone feeding means (13) are extending from a chamber wall (7) of said one or more chamber walls (7, 8) to an opposite chamber wall (8), and wherein said third vertical level (14) is vertically below7said second vertical level (12).

3. An ozone decontamination plant (1) according to claim 1 and 2, wherein said one or more first level ozone feeding means (9) comprises first level flow7control means (15) arranged to control the flow of ozone into said decontamination chamber (4) at said first vertical level (10) and wherein said one or more third level ozone feeding means (13) comprises third level flow control means (16) arranged to control the flow of ozone into said decontamination chamber (4) at said third vertical level (14).

4. An ozone decontamination plant (1) according to claim 2 or 3, wherein said one or more first level ozone feeding means (9) arranged at a first vertical level (10), said one or more gas extraction means (11) arranged at a second vertical level (12) and said one or more third level ozone feeding means (13) arranged at a third vertical level (14) together forms a first decontamination zone (17) inside said decontamination chamber (4), wherein said decontamination chamber (4) further comprises at least one further decontamination zone (18) inside said decontamination chamber (4), wherein said at least one further decontamination zone (18) also comprises one or more first level ozone feeding means (9) arranged at a first vertical level (10), one or more gas extraction means (11) arranged at a second vertical level (12) and one or more third level ozone feeding means (13) arranged at a third verticallevel (14) and wherein said at least one further decontamination zone (18) is arranged below said first decontamination zone (17).

5. An ozone decontamination plant (1) according to any of the preceding claims, wherein said ozone feeding means (9, 13) and said gas extraction means (11) comprises baffles (19) each comprising an upward facing apex (20) between two downward sloping sides (21) as seen from said chamber wall (7) towards said opposite chamber wall (8).

6. An ozone decontamination plant (1) according to claim 4 or 5, wherein said ozone feeding means (9, 13) comprises an ozone inlet (22) arranged below said apex (20) of said baffles (19) and wherein said gas extraction means (11) comprises a gas outlet (23) arranged below said apex (20) of said baffles (19).

7. An ozone decontamination plant (1) according to any of the preceding claims, wherein said ozone decontamination plant (1) further comprises ozone level detection means (24) arranged to detect an ozone level at said one or more gas extraction means (11) and control means (25) arranged to control the gas extraction speed at said one or more gas extraction means (11) in response to input from said ozone level detection means (24).

8. An ozone decontamination plant (1) according to any of the preceding claims, wherein said decontamination chamber (4) further comprises two or more kernel moving means (26) arranged substantially side by side across said bottom of said decontamination chamber (4) above said at least one lower kernel outlet (6), wherein said two or more kernel moving means (26) are arranged to actively move said kernels (2) towards said at least one lower kernel outlet (6).

9. A method for decontaminating kernels (2), said method comprising the steps of:. guiding kernels (2) into a decontamination chamber (4) through at least one upper kernel inlet (5) arranged at a top of said decontamination chamber (4),. removing kernels (2) from said decontamination chamber (4) through at least one lower kernel outlet (6) arranged at a bottom of said decontamination chamber (4),. guiding ozone from an ozone production unit (3) into said decontamination chamber (4) by means of one or more first level ozone feeding means (9) arranged at a first vertical level (10) inside said decontamination chamber (4), wherein said one or more first level ozone feeding means (9) are fluidly connected to said ozone production unit (3) producing said ozone, wherein said one or more first level ozone feeding means (9) are extending from a chamber wall (7) extending between said top and said bottom of said decontamination chamber (4) to an opposite chamber wall (8) extending between said top and said bottom of said decontamination chamber (4), wherein said ozone is guided into said decontamination chamber (4) while said kernels (2) are traveling down through said decontamination chamber (4) from said at least one upper kernel inlet (5) to said at least one lower kernel outlet (6),. extracting gas from said decontamination chamber (4) by means of one or more gas extraction means (11) arranged at a second vertical level (12) inside said decontamination chamber (4), wherein said one or more gas extraction means (11) are extending from said chamber wall (7) to said opposite chamber wall (8), wherein said first vertical level (10) is vertically higher than said second vertical level and wherein said gas is extracted from said decontamination chamber (4) while said kernels (2) are traveling down through said decontamination chamber (4) from said upper kernel inlet (5) to said lower kernel outlet (6) and while said ozone is guided from an ozone production unit (3) into said decontamination chamber (4) by means of said one or more first level ozone feeding means (9).

10. A method according to claim 9, wherein a gas extraction speed of said one or more gas extraction means (11) is controlled in response to an ozone level at said one or more gas extraction means (1 1).

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