FR2498876A1 - Mobile plant for irradiating agricultural prod. to prevent germination - has vertical radioactive rod surrounded by rotating prod. containers - Google Patents

Abstract

The plant is of the type in which the prod. is treated inside a container located alongside a source of radiation. The prod. container and source are enclosed in a radiation-absorbent casing. The casing encloses a vertical, cylindrical, irradiation chamber contg. a bar of radioactive material coinciding with the vertical axis of the chamber. At least three prod. containers, each of vertical cylindrical form, are disposed symmetrically around the radioactive bar. Each container is power-rotated about its vertical axis. Each container has a top entry for prod. introduced from an independent hopper outside the casing. The container also has a removable base operable from the exterior of the casing to discharge treated prod. towards a single casing outlet. Irradiation is carried out at the location where the crop has just been harvested. The plant is easy to transport and to operate. It is much more compact than previous batch or continuous irradiation installations in factories, etc.

Description

 The invention relates to a device for the irradiation of agricultural products at the places of production, after harvest.

 It is known to subject certain agricultural products to irradiation immediately after harvest, at the places of production, to stop the germination of these products.

 This is the case, for example, for bulbs or tubers such as potatoes for which the use of such a process makes it possible to avoid having to resort to chemicals which cause germination to stop.

 Indeed, the treatment by irradiation is much faster and much easier to implement than a method of treatment with a chemical product.

 For the implementation of the irradiation process on the production sites, just after uprooting, one can use irradiators which include either an enclosure similar to that of an oven into which the products are introduced and then extracted after irradiation, or containers entering through baffles in casemates containing radioactive sources in front of which the containers containing the products to be irradiated are scrolled. In this case, the sources are generally constituted by several bars of radioactive materials arranged in rows inside the casemate.

 Oven-type irradiators most often only accept limited volumes of product at each load and, on the other hand, handling the product both when unloading and unloading the oven results in complex operations.

 Installations comprising containers running past radioactive sources arranged in casemates can be extremely bulky when it is desired to obtain a large production capacity, taking into account the arrangement of the radioactive sources and baffles necessary for the transfer of the containers .

 The device for moving the container is extremely complex because, during irradiation, it is necessary to present the different faces of the container successively near the radioactive source, in order to obtain homogeneous irradiation.

 All these devices lead to very high cost prices which make them reserve for expensive products.

 On the other hand, it is desirable to carry out irradiation at the places of production and therefore to have mobile installations which can be moved and put into service quickly and easily.

 The object of the invention is therefore to propose a device for the radiation of agricultural products, on the places of production, after harvesting, comprising a radioactive source, inside a protective enclosure absorbing radiation and containers inside which there are agricultural products, for their irradiation, in the enclosure, in the vicinity of the radioactive source, this device having to be simple and space-saving and easy to transport and to implement, d '' high productivity and safety in use while having a low cost making it applicable to inexpensive products.

 For this purpose, the interior volume of the protective enclosure is substantially symmetrical in revolution about a vertical axis, the single radioactive source, of elongated shape being arranged along this axis of revolution and at least three containers of cylindrical shape are arranged. with their axes parallel to the axis of the enclosure around the active source, movable in rotation around their axes by means of support and motor means integral with the protective enclosure, protective enclosure also comprising: - at its upper part, means of supplying agricultural products from each of the containers, the upper part of which comprises an inlet opening for these products and the lower part of which is closed off by an opening bottom connected to an opening and closing, at defined time intervals, of this opening bottom, for emptying or retaining products, - and means for evacuating products, at its lower part ure, below the opening bottom of the containers.

 In order to clearly understand the invention, a description will now be given, by way of nonlimiting example with reference to the single figure appended, to a device for irradiating agricultural products according to the invention.

 The single figure is a sectional view through a vertical plane of symmetry of the device according to the invention.

 In the single figure, we see the protective enclosure 1 with "thick walls, the internal space of which is limited by a cylindro-conical surface having the axis of revolution ZZ '.

In the center of this internal space of enclosure i, along the axis
ZZ ′, is arranged an irradiation chamber 2 enclosing a rod made of radioactive material 3 constituting the irradiation source.

 Inside the enclosure 1, around the irradiation chamber 2 are arranged four satellites such as 5 and 6 shown in the single figure and which constitute the containers intended to receive the products to be irradiated.

 The four containers are placed at equal distance from the irradiation chamber and the source of radioactive radiation 3, the positions of these four containers being deduced from one of them by rotations of 900 around the axis ZZ ' .

 All the containers are identical and we will confine ourselves to describing the container 5.

 This container comprises a lateral cylindrical casing 7 with a vertical axis Z1 Z'1 secured to a drive unit 8 itself secured to the axis 9 of a motor 10 fixed on the upper part of the enclosure 1, the axis 9 crossing the thick wall thereof.

 The motor 10 allows the cylindrical casing 7 of the container 5 to be made to rotate continuously around the axis Z1 Ztl.

 The upper end of the container 5 is open and communicates with the outlet of a hopper 11, the inlet of which is placed in the extension of a channel 12 formed in the enclosure i and constituting the power supply line for the satellite 5.

 The channel 12 opens into a well 13 inside which opens the outlet end of a dosing hopper 14 resting on a support 15 fixed on enclosure 1 and allowing the supply of the container 5 with irradiated agricultural products via the channel 12 and hopper 11.

 At its lower part the container 5 is closed by a bottom opening 16 rotatably mounted around the axis Z1 Z'i by means of a ball bearing 17 whose outer ring is secured to an arm 18 itself connected to a member 20 allowing a displacement by rotation of the cover 16 between a closed position shown in the single figure where the bottom 16 closes the lower end of the cylindrical casing 7 and an open position oA the bottom 16 is no longer in accordance with the lower end of the cylindrical casing 7. This opening is controlled from the upper part by a linkage 26.

 The conical inner part of the enclosure 1 constitutes a hopper in communication with an evacuation channel 21 opening at the lower end of the enclosure 1.

 The presence of baffles on the inlet 12, 13 and on the outlet 21 of the products makes it possible to avoid any danger of irradiation outside the enclosure.

 Also shown in the single figure is the container 24 allowing the transport of the radioactive source in the form of a bar similar to the radioactive bars 3. This transport container can be placed on the enclosure 1 directly above the irradiation chamber 2 with which it can be brought into communication, either for the removal of the radioactive source or on the contrary for the lining of the irradiation chamber with a bar 3, by means of a device 25 carrying out the displacement loads in the direction Z Z '.

 For safety reasons, it is even necessary to keep this container during the irradiations, this container also being locked on the device when the source is in the working position.

 Security systems prohibit any intervention at dismantling on the irradiation device, as long as the transport container 24 and the radioactive sources have not been evacuated.

We will now describe the operation of the irradiation device according to the invention, during the processing of agricultural products.
them, such as potatoes which have just been uprooted.

 The irradiation device shown in the single figure is brought to the place of harvest. For its movements, this device is mounted on a trailer which has not been shown.

 The harvested agricultural products are poured into the dosing hopper 14 which allows the filling, via 11 of the well 13, of the channel 12 and of the hopper 11 of the container 5.

 During the filling of the container 5, the envelope 7 is in continuous rotation, the motor 10 being in operation.

 I1 therefore occurs a regular filling of the container 5 and a rotational drive of the bottom 16, when the weight and the friction of the products poured into the container 5 are sufficient to carry out the training thereof.

The filling of the container 5 being completed, or during this filling, it is possible to fill the other containers such as 6 of
the same dewlap thanks to their corresponding feeding device. All these devices are autonomous and can operate simultaneously.

 It should be noted that the filling of these containers can be done with agricultural products identical to those filling the container 5 or with different agricultural products.

 The container 5 is kept in continuous rotation, the radioactive rod 3 being in position in the chamber 2 and the container 1 remaining connected to the enclosure.

 The agricultural products filling the container 5 are therefore exposed to the radiation emitted by the bar 3 in a homogeneous manner by virtue of the continuous rotation about its axis of the container 5 and of the products that it contains.

 There is thus obtained a great homogeneity of irradiation in the whole load of the agricultural product contained in the container.

 Depending on the intensity of the source, a necessary irradiation time is determined for the products contained in the container 5 and when this time has elapsed, a timed control of the rotating member 20 allows the opening of the bottom 16 and a flow of agricultural products in the channel 21 via the lower part of the enclosure 1 constituting a hopper.

 The correctly irradiated product can then be collected at the outlet of the channel 21 in a means of transport placed below this outlet.

 Refilling the container 5 with a new load of agricultural products to be treated is possible.

 The operation of the other satellites is identical to the operation of satellite 5, the irradiation times can however be different if the products are themselves different.

 After a certain operating time, corresponding to the lifetime of the radio-element, the station is re-equipped with a new source.

 Refitting and recharging from a new source takes place during a period when the station is not in use.

 On the other hand, if a fault occurs for example on the drive motor of one of the satellites, the other satellites can continue to operate and the repair can be carried out without stopping the installation, the mechanical and electrical drive parts satellites being outside enclosure 1.

 The device according to the invention therefore makes it possible to ensure absolutely continuous operation during the harvest.

 To obtain a good homogeneity of irradiation of the product, the diameter of the satellites will be chosen according to the characteristics of the source and of the product to be treated.

 To obtain a device with high productivity, satellites of great length relative to their diameter will be chosen.

 The efficiency of the installation can be improved by placing diffusing masses in the directions which would correspond to radiation leaks decreasing the efficiency of the source, namely / the satellites and in the vicinity of the ends of the bar 3.

 We see that the device according to the invention is of a very simple design but that despite everything its operation is fully automatic and very safe, since all handling inside the device is ensured by gravity.

 On the other hand, the device can be easily disassembled and transported since it is designed largely in modular form.

 To facilitate these dismantling and transport, it was possible to build a highly productive irradiation device, the most massive element of which weighed less than 20 tonnes and the largest part of which did not exceed three meters.

 Another advantage of the device according to the invention is that the satellites can be easily dismantled and replaced so as to be adapted to the type and nature of the product, to its geometry, to its structure at the required radiation dose and to the homogeneity. requested irradiation.

 Another advantage of the device according to the invention is that it does not include any functional dynamic element which is subjected to the radiation flow inside the protective enclosure. Thus, it is possible to easily carry out maintenance and repair of the various mechanical or electrical drive members which are located outside of the protective enclosure. The device can operate with a single radioactive bar. This bar can be made up of several rods of radioactive material.

 Finally, by its very good irradiation efficiency, this design results in a cost price much lower than all the devices currently known and allows its application to very low cost foodstuffs.

 The embodiment which has just been described is not limiting and it is possible to modify details without departing from the scope of the invention.

 Thus a device comprising four satellites has been described, but it is possible to imagine a device comprising any number of satellites distributed regularly around the radiation chamber, for example six satellites. However, it is not desirable to use less than three satellites arranged at 1200 around the irradiation chamber because then the efficiency of the radioactive source would decrease considerably.

 it is also possible to imagine other modes of introduction or removal of the product to be irradiated or irradiated, just as one can imagine other modes of driving in rotation of the satellites and other modes of realization of funds opening than those which have been described.

 Finally, the device according to the invention applies in the case of treatment by irradiation of any agricultural products.

Claims (4)

 1.- Device for the irradiation of agricultural products, on the places of production after the harvest, comprising a radioactive source inside a protective enclosure absorbing radiation and containers inside which agricultural products are available, for their irradiation in the enclosure, in the vicinity of the radioactive source, characterized in that the interior volume of the protective enclosure is substantially symmetrical of revolution about a vertical axis, the single radioactive source of elongated shape being arranged along this axis of revolution and that at least three cylindrical containers are arranged with axes parallel to the axis of the enclosure around the radioactive source, movable in rotation around their axes gus ce to support means and to motor means integral with a protective enclosure, the protective enclosure comprising - at its upper part, means for supplying agricultural products from each containers the upper part of which has an inlet opening for these products and the lower part of which is closed off by an opening bottom connected to an opening and closing device, at defined time intervals of this opening bottom, for the draining or retaining the products, - and means for removing the products, at its lower part, below the opening bottoms of the containers.  2.- dtirradiation device according to claim 1 characterized in that the containers comprise a cylindrical lateral envelope connected to the vertical axis of rotation of a motor disposed outside the protective enclosure and an opening bottom horizontal freely rotatably mounted on a vertical axis and carried by a member for moving these opening bottoms, by rotation between a closed position and an opening position, these opening bottoms being driven in rotation by the products that can fill the container when the opening funds are in the closed position.  3.- Irradiation device according to any one of the preceding claims, characterized in that it comprises four identical containers whose axes are placed at equal distance from the axis of the protective enclosure and whose positions are deduced by rotations of 900 around this axis.  4. Irradiation device according to any one of claims 1, 2 and 3, characterized in that the protective enclosure has a closable opening above its axial part constituting the irradiation chamber, for the provision of a container for transporting radioactive sources for unloading or loading the irradiation chamber.