METHOD FOR CONTROLLING AN AIR CONVEYOR SYSTEM

Abstract

TITLE: METHOD FOR CONTROLLING AN OVERHEAD CONVEYOR SYSTEM The invention relates to a method for controlling an overhead conveyor system for multi-stage transport devices. The conveyor system comprises: a main conveyor (6) for moving the transport devices (7) to an inlet (51) of the processing zone (5) and from an outlet (52) of said zone (5), an auxiliary conveyor arranged in the processing zone (5), and a means for transferring the transport devices (7). The method comprises the following steps: holding the device in an injection zone (Zi) upstream and adjacent to the inlet (51), sensing the device by the transfer means, receiving information that a drive device is available to the auxiliary conveyor, and transferring the transport device to bring it into contact with said drive device. Figure for the abstract: Figure 1.

Description

Title of the invention: METHOD FOR CONTROLLING AN OVERHEAD CONVEYOR SYSTEM Technical field of the invention

[0001] The present invention relates to the field of aerial conveyance of loads. More particularly, it relates to a method for controlling a conveyor system of multi-shelf transport devices capable of transporting articles to be processed in a processing area. State of the art

[0002] In this field, usually the conveying of the transport devices carrying the articles to be treated is done using floor conveyors which causes problems among others of wear of the on-board electronic and electromechanical components which are exposed to radiation during repeated passages in the treatment zone. The solution found for this problem is to use an overhead conveying system in which the article transport devices are suspended and moved along a circuit passing through the treatment zone. Such a system has the advantage that only mechanical trolleys to which the transport devices are suspended pass through the treatment zone. The absence of a floor conveyor also provides a gain in irradiation performance, by leaving space for the product to be treated in front of the treatment beam.

[0003] However, known overhead conveyor systems are not suitable for installations in which the products require specific treatment. Indeed, in such a treatment area, it is necessary for all the items to undergo homogeneous treatment at sufficient doses. The process therefore requires low speeds and high stability, which is not compatible with the rate generally imposed by the treatment installation.

[0004] It is therefore important that the process control is well mastered.

[0005] The invention therefore aims to propose a solution making it possible to maintain a nominal rate in the treatment installation while controlling the conditions of movement of the transport devices in the treatment zone and thus ensuring good treatment of the products. Summary of the invention

[0006] To this end, the invention relates to a method for controlling an overhead conveying system of suspended multi-stage transport devices, capable of carrying articles to be treated in a treatment zone by an ionizing beam, the conveying system comprising: - a main conveyor having drive means at a first speed, configured to move the transport devices to an entrance of the treatment zone and from an exit of said zone, - an auxiliary conveying device arranged in the treatment zone and carrying a plurality of drive devices capable of driving successive and adjacent transport devices, from the inlet to the outlet, according to a running speed determined as a function of the articles to be treated, said running speed being lower than the first speed, and - a means of transferring transport devices, arranged in the vicinity of the entrance,

[0007] wherein the method comprises the following steps:

[0008] - a holding of a transport device in an upstream injection zone and adjacent the entrance,

[0009] - a seizure of the transport device by the transfer means in the area injection,

[0010] - a reception of information that a training device is available at the auxiliary conveying device, and

[0011] - a movement of the transport device by the transfer means to put it in contact with said drive device.

[0012] Putting a transport device in a waiting position makes it possible, on the one hand, to avoid having a collision with a transport device already driven by the auxiliary device, and therefore to choose the right moment to move it towards the treatment zone. On the other hand, it is ensured that adjacent transport devices are constantly passing in front of the treatment beam forming a train, so that the beam is always interrupted by a transport device and does not impact the wall in the background. Energy losses are therefore reduced. Furthermore, the rate is maintained by avoiding defusing the flow.

[0013] The use of the auxiliary conveying device for movement and stabilization therefore allows good control of the stability of the transport devices and their speed, which guarantees uniform treatment. The movement pitch is for example chosen so that the movement devices are stuck to each other in the treatment zone. They thus form a sort of train which avoids any loss of energy which can occur if the devices are spaced apart.

[0014] The speed of movement can furthermore be linked to the desired treatment dose for the products, this can be the case in particular in the case of treatment of the products by radiation, the speed of movement can be decisive for the dose of radiation received, for example to sterilize the products.

[0015] The radiation is for example ionizing radiation, for example with

[0016] X-rays, gamma rays or an electron beam. The method may further comprise: A waiting period for a transport device in a preparation area upstream of the injection area, Receiving information that a location is available in the injection area, A transfer of a transport device from said preparation area to the injection area by the main conveyor and optionally putting it on hold.

[0017] In this way, it is ensured that there is always a transport device ready to be transferred to the injection zone where it will be taken over by the transfer means. Thus, the rate is maintained.

[0018] The method may also comprise: A waiting period for one or more transport devices in an accumulation area upstream of the preparation area, Receiving information that a location is available in the staging area, A transfer of a transport device from said accumulation area to the preparation area by the main conveyor and optionally putting it on hold.

[0019] Advantageously, the method may further comprise at least one additional step of placing a transport device on standby in an additional accumulation zone.

[0020] The accumulation zones allow: to always have transport devices ready to be injected into the downstream automatic stations to respect a certain rate imposed by the system while avoiding defusing the flow. to stock enough transport devices to meet varying throughput needs.

[0021] Advantageously, the method may comprise a step of identifying a transport device upstream of the treatment zone. The identification of the transport device makes it possible to monitor the treatment.

[0022] Advantageously, the method may further comprise a step of deciding to send a transport device to a rotation zone (R) in which the transport device is rotated 180° along its vertical axis. The rotation of the transport device makes it possible to ensure exposure of the articles to the beam from both sides.

[0023] Advantageously, the method may further comprise a step identification of a transport device downstream of the treatment zone and a step of deciding whether said transport device should return through the treatment zone or be directed towards an exit.

[0024] Advantageously, the method may further comprise a decision step to direct a transport device towards an inversion station in which articles from two floors of said device are inverted (top to bottom and vice versa) before a new passage through the treatment zone. The inversion makes it possible to homogenize the treatment dose received by the articles placed on different floors.

[0025] The invention also relates to a computer program comprising instructions for executing the steps of the method as described above.

[0026] The invention also relates to a computer-readable medium comprising the computer program described above.

[0027] The invention further relates to an installation for processing articles in a processing zone, comprising means for generating an ionizing beam and an overhead conveying system of suspended multi-stage transport devices, capable of carrying articles to be processed, the conveying system comprising: - a conveyor having drive means at a first speed, configured to move the transport devices to an entrance of the processing zone and from an exit of said zone, - an auxiliary conveying device arranged in the treatment zone and carrying a plurality of drive devices capable of driving successive and adjacent transport devices, from the inlet to the outlet, according to a running speed determined as a function of the articles to be treated, said running speed being lower than the first speed, and - a means of transferring transport devices, arranged in the vicinity of the entrance.

[0028] The installation further comprising a computer program described above.

[0029] The auxiliary conveying device may comprise a lower chain carrying the drive means such as cleats.

[0030] Advantageously, the auxiliary conveying device may further comprise an upper chain comprising attachment means configured to be secured with guide means arranged in the upper part of the loading devices, said upper chain being synchronized with the lower chain.

[0031] Having an upper chain synchronized with the lower chain allows for greater control of the position of the transport devices along its vertical axis, ensuring good stability by preventing swinging along the axis of advance of the transport devices.

[0032] The synchronization between the upper chain and the lower chain can be performed by a synchronization shaft or any other means of synchronization, such as an additional chain. However, the synchronization shaft has the advantage of being a simple means of synchronization and reinforcing the stability of both the upper and lower chains. Brief description of the figures

[0033] Other features and advantages of the invention will appear in the description below in relation to the appended drawings, given as non-limiting examples, in which:

[0034] [Fig-1] [Fig.l] represents a partial view of an installation illustrating the func operation of an aerial conveyance system according to the invention;

[0035] [Fig.2] [Fig.2] is a view of a portion of the conveyor system showing a conveyor and an overhead transport device;

[0036] [Fig.3] [Fig.3] is a zoom on an area of ​​attachment of a transport device to a conveyor trolley;

[0037] [Fig.4] [Fig.4] is a partial view of a conveyor chain;

[0038] [Fig.5] [Fig.5] is a view of a set of transport devices in the area of treatment.

[0039] In the remainder of the description, elements having an identical structure or similar functions will be designated by the same references. Detailed description

[0040] [Fig.l] represents a schematic top view of a product processing installation 1 comprising a non-sensitive part I partially represented on the right of the figure and a sensitive part II on the left.

[0041] In part I, the installation comprises generally known storage and handling means, such means are not the subject of the invention and are therefore not detailed in this description.

[0042] In part II, the installation comprises protective walls 2 enclosing an emission zone comprising means 3 for generating radiation used for the treatment of articles. The radiation generation means 3 may be means for generating any type of radiation usable in the treatment of articles, for example sterilizing radiation. Such radiation may be, for example, ionizing radiation by X-rays, Gamma rays or an electron beam.

[0043] In other embodiments not shown, the treatment may be different, such as a surface treatment, paint spraying or any other reactive or aesthetic agent.

[0044] The beam 4 produced by the means 3 arrives at a treatment zone 5, the products which are in this zone at the time of impact receive a dose of the beam.

[0045] The protective walls are known per se and may comprise external walls 2 and an internal wall 21 to stop the beam 4 if it hits between two products or between two transport devices 7. It is not necessary here to give more details of such walls which are known per se for such applications.

[0046] To move the articles to be processed, the conveyor system comprises transport devices 7, an example of which is shown in [Fig.2] and [Fig.5], such devices may comprise several stages in which the articles to be processed are loaded.

[0047] To circulate the products to be treated with the beam 4, the installation comprises an overhead conveyor 6 forming a circuit which goes from part I to part II. The products are loaded upstream of the inlet 60 and carried by the conveyor 6 towards part II to pass through the treatment zone 5 to receive one or more doses of the beam, for example by rotating in the internal loop 61. At the end of treatment the products leave through the outlet 62 to go to other stations of the installation in part I, for example to be unloaded and stored.

[0048] The conveyor 6, in the example of Figure 2, comprises a lower part comprising a rolling track 64 on which carriages 8 move, each carrying a suspended transport device 7.

[0049] As shown in [Fig.3], a carriage 8 comprises wheels 81 for rolling on the rolling track 64 and a conveyor device 83 to which the conveyor device 7 is suspended. The carriage 8 further comprises a hooking means 82 which can move from an upper hooking position, allowing the carriage 8 to be driven with the conveyor device 7, to a lower position for stopping the carriage 8 and the conveyor device 7.

[0050] In the illustrated example, the conveyor is a twin-rail conveyor, the upper rail 63 of which, as shown in [Fig.4], comprises rolling means 91 of a traction chain 9. The traction chain rotates continuously and comprises drive devices 92. When a drive device 92 encounters the hooking device 82 in the high position, the carriage is driven along a path predefined by the control system.

[0051] In other embodiments not shown, the conveyor may be monorail or of another type used in overhead conveyor systems.

[0052] In the installation 1, the conveying of the transport devices 7 is done outside the treatment zone 5 at a certain speed defined by the treatment process to respect a certain rate, this speed is relatively high (typically 10 to 20 m / minute) compared to the speed of movement in the treatment zone 5. In the treatment zone to allow each product to receive the defined dose of the treatment and to ensure homogeneous treatment of all the products, it is necessary to ensure movement at another much slower speed (of only a few dm / minute to a few m / min) than in the rest of the circuit defined by the conveyor system. It is also necessary to guarantee the stability of the transport devices 7 which can each have a plurality of shelves and have a high height, which therefore creates risks of tipping.

[0053] To ensure proper processing of the products carried by the transport devices 7, the latter can be moved by moving the carriages 8 by the traction chain 9 to the entrance 51 of the processing zone 5, then the hooking device 82 can be moved to the low position so that the driving of the carriage by the traction chain 9 stops.

[0054] To ensure the driving and stability of the transport devices 7 in the treatment zone 5, the system comprises an auxiliary conveying device arranged in said treatment zone 5. According to the example illustrated, this device has driving means in the lower part configured to cooperate with securing means 71 which are provided in the lower part of each transport device 7.

[0055] The auxiliary conveying device makes it possible to control the movement of the transport devices 7 in the treatment zone 5 at a speed determined according to the articles to be treated and to ensure good stability. Indeed, the drive means, for example in the form of cleats, prevent the transport devices from tilting during their movement at low speed defined by the movement pitch.

[0056] As shown in the example of [Fig.5], the auxiliary conveying device may comprise a lower chain 13 composed of links 131 and carrying drive means 132 in the form of cleats.

[0057] It may also comprise an upper chain 12 composed of links 121 and carrying additional drive means 122 also in the form of cleats. The additional cleats are configured to cooperate with additional guide means arranged in the upper part of the transport devices.

[0058] Advantageously, the upper chain 12 is synchronized with the lower chain 13. The synchronization between the upper chain 12 and the lower chain 13 can for example be carried out by a synchronization shaft 14. Alternatively, the synchronization can be carried out by an additional chain.

[0059] Furthermore, to ensure the centering of the transport device 7, the system may also comprise a lower guide rail 11 arranged to receive a centering element, arranged in the lower part of the transport devices 7.

[0060] The system also comprises a transfer device 10 as shown in [Fig.2]. The device 10 is arranged to move the transport devices 7 from the waiting position in the injection zone to the place where it is brought into contact with the auxiliary conveying device.

[0061] The installation also includes a computer program which controls the operation of the installation. Example of operation:

[0062] Preparatory operations are carried out in the unshown part of Part I, such operations may include: - the removal of items from stock, for example carried on a customer's pallet, - a transfer onto a secondary pallet bearing a means of identification, such as that a QR code engraved on said secondary pallet, to track the pallet, - a transfer of secondary pallets, each carrying a pallet containing items to be processed, into transport devices (7), for example on two or three floors.

[0063] The loaded transport devices 7 can undergo one or more identifications SI in part I, the system identifies each device 7 moved by the main conveyor 6 before arriving at the entrance 60, it then undergoes other identifications S2, S3 before the processing zone 5 and other S4, S5 after this zone 5. In this way, the system can individually track the transport devices 7 and determine the next destination.

[0064] The transport devices 7 arriving at the input 60 continue on the incoming circuit passing through accumulation zones Za8, Za6, and Za4 in which, depending on the rate requirement, the control method can comprise steps of accumulation in each of said zones and releasing them one by one by activating an O / F opening / closing means. At the output of Za4, the devices 7 are sent one by one into the internal loop 61 passing through the treatment zone 5 when the number of devices already present in this zone is less than the maximum capacity that the internal loop 61 can accept. They then arrive in an accumulation zone Za2 upstream of a rotation device R. Each transport device 7 leaving the accumulation zone Za2 is therefore identified by the means S3 which can decide whether or not it needs to pass through a rotation step by the device R which turns it 180° to change the side exposed to the beam 4.Transport devices 7 having already made one or more passes through the treatment zone 5 and redirected to Za2 and exit from the accumulation zone Za3 can also arrive at the accumulation zone. In the case where rotation is not necessary, the devices 7 continue towards the downstream zone Zal.

[0065] The transport devices arriving at the accumulation zone Zal are systematically stopped for good control of the flow of devices 7 passing through the treatment zone 5 and exposed to the beam 4. This first accumulation zone Zal makes it possible to systematically have a reserve of transport devices 7 to be sent to the zone 5 while avoiding forming holes in the train of devices 7 passing in front of the treatment zone 5.

[0066] To ensure good control of the flow, a transport device 7 is sent into the preparation zone Zp as soon as a place becomes available in this zone Zp. Then, if a place is available in the introduction zone Zi, said device is transferred from the preparation zone Zp to the introduction zone Zi. In this zone, the transport device 7 is prepared by being introduced into the treatment zone 5 in which the running speed is reduced. Furthermore, the auxiliary conveying device is configured to allow the transport devices arriving at the zone 5 to form a sort of train by being adjacent to each other during their running to pass in front of the treatment beam 4.When a place is available in the treatment zone 5 (therefore a means of driving the auxiliary conveyor device 12, 13 is available), the transfer device 10 moves the transport device present in the introduction zone Zi towards the treatment zone 5 to put it in contact with the auxiliary conveyor device 12, 13 which ensures its drive between the inlet 51 and the outlet 52 of the treatment zone 5. Then, the main conveyor 6 continues the conveyance of said device arrived at the outlet 52 to pass it through the accumulation zone Za3 in which it can accumulate with other devices 7 if this is determined by the system.

[0067] At the exit from zone Za3, an identification is carried out by means S4, which allows the control program to determine a destination from among: - a new passage through the accumulation zone Za2, to go through the stages described above, or - directed to an exit 62, 63. A new identification by means S5 makes it possible to decide whether the device has had a complete treatment and must therefore be directed to exit 62 so that it can be unloaded and the articles put back into stock, or whether the treatment is partial and therefore it is sent to an inversion station (not shown) via exit 63, then arrive again at entry 60 after inversion of the lower pallets with the upper pallet.

[0068] Optionally, accumulations can be carried out in the accumulation zones Za5 and Za7.

Claims

Claims

1. Method for controlling an overhead conveying system of suspended multi-stage transport devices (7) capable of carrying articles to be treated in an area (5) of treatment by an ionizing beam, the conveying system comprising: - a conveyor (6) having drive means at a first speed (VI), configured to move the transport devices (7) to an inlet (51) of the treatment area (5) and from an outlet (52) of said area (5), - an auxiliary conveying device (12, 13, 14) arranged in the treatment area (5) and carrying a plurality of drive devices (122, 132) capable of driving successive and adjacent transport devices (7), from the inlet (51) to the outlet (52), according to a running speed (V2) determined as a function of the articles to be treated, said running speed (V2) being lower than first gear,and - a transfer means (10) for transport devices (7), arranged in the vicinity of the inlet (51), in which the method comprises the following steps: - a waiting of a transport device (7) in an injection zone (Zi) upstream and adjacent to the inlet (51), - a gripping of the transport device (7) by the transfer means (10) in the injection zone (Zi), - a reception of information that a drive device (122, 123) is available at the auxiliary conveying device (12, 12, 14), and - a movement of the transport device (7) by the transfer means (10) to bring it into contact with said drive device (122, 123).,

2. Method according to the preceding claim, further comprising: - Placing a transport device on hold in a preparation zone (Zp) upstream of the injection zone (Zi), - Receiving information that a location is available in the injection zone (Zi), - A transfer of a transport device (7) from said preparation zone (Zp) to the injection zone (Zi) by the main conveyor (6).

3. Method according to the preceding claim, further comprising: - Placing one or more transport devices on standby in an accumulation zone (Zal) upstream of the preparation zone (Zp), - Receiving information that a location is available in the preparation zone (Zp), - Transferring a transport device (7) from said accumulation zone (Zal) to the preparation zone (Zp) by the main conveyor (6).

4. Method according to the preceding claim, further comprising at least one additional step of placing one or more transport devices (7) on standby in an additional accumulation zone (Za2, Za3, Za4, Za5, Za6, Za7, Za8).

5. Method according to one of the preceding claims comprising a step of identifying a transport device upstream of the treatment zone (5).

6. A method according to the preceding claim further comprising a step of deciding to send a transport device to a rotation zone (R) in which the transport device (7) is rotated 180°.

7. Method according to one of claims 5 or 6, comprising a step of identifying a transport device (7) downstream of the treatment zone (5) and a step of deciding whether said transport device (7) must pass through the treatment zone (5) again or be directed towards an exit (62).

8. Method according to one of claims 4 to 7 further comprising a step of deciding to direct a transport device towards an inversion station in which articles of two stages of said device are inverted before a new passage through the treatment zone (5).

9. Computer program comprising instructions for carrying out the steps of the method according to one of the preceding claims.

10. A computer-readable medium comprising the computer program according to the preceding claim.

11. Installation for processing articles in a processing zone (5), comprising means for generating (3) an ionizing beam (4), and an aerial conveying system of suspended multi-stage transport devices (7) capable of carrying articles to be processed, the conveying system comprising: - a conveyor (6) having drive means at a first speed (VI), configured to move the transport devices (7) to an inlet (51) of the treatment zone (5) and from an outlet (52) of said zone (5), - an auxiliary conveying device (12, 13, 14) arranged in the treatment zone (5) and carrying a plurality of drive devices (122, 132) capable of driving successive and adjacent transport devices (7), from the inlet (51) to the outlet (52), according to a running speed (V2) determined as a function of the articles to be treated, said running speed (V2) being lower than the first speed, and - a transfer means (10) of transport devices (7), arranged in the vicinity of the inlet (51), the installation further comprising a computer program according to claim 8.

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