Cleaning process for reusable containers

Abstract

The present invention relates to a method for cleaning reusable containers (10) by means of a cleaning installation (76), the containers (10) comprising residues (24) of sealing film on a portion to be cleaned (27), the method comprising the following steps: - E1: placing a container (10) to be cleaned on conveying means (30), - E2: conveying the container (10) by the conveying means (30) to an abrasion station (32), - E3: removing the residues (24) of film by abrasion by means of a flexible abrasive element (62) from the abrasion station (32), - E4: ejecting the containers (10) from the abrasion station (32). Figure for abstract: 4

Description

Title of the invention: Method for cleaning reusable containers Technical field of the invention

[0001] The present invention relates to the field of reusable containers and more particularly the cleaning of containers after use in order to allow a new use and in particular a new sealing of the container, the sealing consisting of thermally sealing a film on the container.

[0002] The invention relates more particularly to a method for cleaning reusable containers and an installation for cleaning reusable containers. Technical background

[0003] In a context of waste reduction, the use of reusable containers is growing. Reusable containers are for example made of stainless steel, commonly called stainless steel or stainless steel, which allows them to be reused thanks to good mechanical resistance and resistance to corrosion.

[0004] Currently, reusable containers, for example in collective catering, are covered with a removable lid or stretch film. However, in order to guarantee better preservation of products, in particular to meet the requirements of the food industry or large-scale distribution, there is an interest in sealing reusable containers. However, the welding of a lid on a stainless steel container must be relatively strong, otherwise the seal is not guaranteed.

[0005] Tests have shown that a conventional washing cycle in an aqueous solution does not remove film and glue residues left on the containers, regardless of the duration of the soaking phase or the temperature of the solution used. Indeed, after washing, the containers have traces of residual film which could compromise the sealing of a new sealing of the containers or harm the quality of subsequent sealings, for example by introducing contamination linked to plastic residues.

[0006] There is therefore an interest in proposing an installation and a method for cleaning reusable containers guaranteeing the elimination of film and glue residues. Summary of the invention

[0007] The invention provides a method for cleaning reusable containers by means of a cleaning installation, the containers comprising residues of sealing film on a portion to be cleaned, the method comprising the following steps:

[0008] - El: placing a container to be cleaned on transport means,

[0009] - E2: transport of the container by the transport means to a station abrasion,

[0010] - E3: removal of film residues by abrasion using an abrasive element flexible abrasion station,

[0011] - E4: ejection of containers from the abrasion station.

[0012] According to other characteristics of the invention:

[0013] - step E3 of removing film residues comprises bringing the portion to be cleaned with at least one rotating brush with an axis of rotation substantially orthogonal to the portion to be cleaned;

[0014] - in step E3 of removing film residues, the rotating brush used comprises abrasive flaps extending in radial planes;

[0015] - in step E3 of removing film residues, the container passes from a first row of rotating brushes to a second row of rotating brushes, the direction of rotation of the rotating brushes being reversed between the first row and the second row;

[0016] - the process comprises a first preliminary stage PI of pre-washing the containers before step E3 of residue disposal;

[0017] - the process comprises a second preliminary step P2 of drying the container after the first preliminary stage PI of pre-washing the containers and before stage E3 of removing residues,

[0018] - step E2 of transporting the container is carried out by a belt conveyor;

[0019] - step E2 of transporting the container comprises maintaining the container at the by means of a rough cloth driven by an upper roller rotating around a transverse axis and placed at a distance corresponding to a container height from the conveying means, so that when the container is placed between the rough cloth and the conveying means, the rough cloth adheres to the container and drives it in a longitudinal translational movement.

[0020] The invention also proposes an installation for cleaning reusable containers, the containers comprising residues of sealing film on a portion to be cleaned, the cleaning installation being characterized in that it comprises:

[0021] - a drying station comprising means for drying the containers,

[0022] - an abrasion station comprising at least one flexible abrasive element designed for remove film residue from the area to be cleaned,

[0023] - means for conveying the containers capable of conveying the containers to the less until the abrasion station.

[0024] The container cleaning installation may further comprise, upstream of the drying station, a pre-washing station comprising means for removing any remaining contents from the containers. Brief description of the figures

[0025] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0026] [Fig-1] is a perspective view of a reusable container after pre-washing showing film and glue residue on a portion of the container to be cleaned;

[0027] [Fig.2] is a cross-sectional view of the container of [Fig.l] showing the geometry of the container;

[0028] [Fig.3] is an enlargement of a detail of [Fig.2] showing the geometry of the portion of the container to be cleaned;

[0029] [Fig.4] is a schematic longitudinal sectional view of a cleaning machine according to one embodiment of the invention;

[0030] [Fig.5] is a perspective view of the entrance to the machine of [Fig.4] in which the means of transport and the means of maintenance are visible;

[0031] [Fig.6] is a side view of the abrasion station of the machine of [Fig.4];

[0032] [Fig.7] is a perspective and bottom view of the abrasion station of the machine of [Fig.4];

[0033] [Fig.8] is a flowchart of a cleaning installation according to a method of rea illustration of the invention showing the succession of container processing stations;

[0034] [Fig.9] is a flowchart of a method according to an embodiment of the invention. Detailed description of the invention

[0035] For the description of the invention and the understanding of the claims, the vertical, longitudinal and transverse orientations according to the reference V, L, T indicated in the figures, the longitudinal L and transverse T axes of which extend in a horizontal plane, will be adopted as a non-limiting example and without limiting reference to Earth's gravity. By convention, the vertical axis is oriented from bottom to top, the longitudinal L axis is oriented from back to front and the transverse axis is oriented from right to left.

[0036] In the following description, identical, similar or analogous elements will be designated by the same reference numbers.

[0037] In the context of the use of reusable containers within the food industry or large-scale distribution, the cyclical circuit of reusable containers can be as follows: - a reusable container distribution company supplies empty, clean, ready-to-use containers to an industrialist or a store, - the manufacturer or store fills the containers with a product and then produces the sealing of full containers and sells the products thus packaged at a point of sale, - the consumer, or the store in the event of the use-by date being exceeded, opens a container and empties it of its product, - the consumer or the store rinses the container, - where applicable, the consumer returns the container to the point of sale, - the container distribution company collects the emptied and rinsed containers at the point of sale, - the container distribution company cleans the recovered containers in order to obtain new empty and clean containers ready for use which can start a new cycle.

[0038] The process indicated with the different actors involved could be different: certain operations can be subcontracted to other actors, certain operations can be carried out by another actor.

[0039] A reusable container means any container capable of: - receive content, - be sealed, - be collected and then cleaned for later use.

[0040] Thus, the term container can designate trays, dishes, pots, plates or any other container.

[0041] Reusable containers are, for example, made of stainless steel, which gives them good mechanical strength and good resistance to corrosion. Reusable containers can also be made of stoneware or glass.

[0042] For the sealing of stainless steel containers, special films are used. Their structure can be, among others, Poly Ethylene Terephthalate, Poly Amide, Poly Propylene, Poly Ethylene, Poly Vinyl Chloride, Aluminum, Paper and other plant fibers.

[0043] Their welding layer can be composed, among other things, of a mixture or a pure form of Poly Ethylene, Ethylene Vinyl Acetate, or Poly Ethylene Terephthalate.

[0044] Other materials acting as a barrier to gases, light, or even anti-fog can also be found there. These materials can be incorporated in layers or in the mass of the film.

[0045] Figures 1 to 3 give examples of containers, in particular with a particular geometry. It is understood that other containers with different geometric shapes can also be treated within the scope of the invention.

[0046] [Fig.l] shows a reusable container 10 after the step in which the consumer or store rinses the container. It can be seen in the figure that the container 10 is still wet after rinsing. With reference to figures 1 to 3, container 10 is a stainless steel tray comprising: - a rectangular bottom 12 in the lower part, - a side wall 14 extending in height along the perimeter of the bottom 12, and - an upper edge 16 extending the side wall 14 in a substantially horizontal plane.

[0047] The upper edge 16 is extended by a rim 18 extending downwards from the periphery of the upper edge 16. The container 10 further has a first rounded portion 20 connecting the side wall 14 to the upper edge 16 and a second rounded portion 22 connecting the upper edge 16 to the rim 18.

[0048] As shown in [Fig.l], the upper edge 16 has residues 24 of film and glue. Indeed, sealing on stainless steel requires a particularly strong weld of the sealing film on the upper edge 16, the weld being resistant to water and temperature. Furthermore, the weld is not carried out exclusively on a flat surface since the weld carried out on the upper edge 16 extends over the rounded areas 20 and 22.

[0049] Indeed, as shown in figures 2 and 3, the container 10 comprises a welding surface 26 in the shape of an inverted U comprising the upper edge 16 and the first and second rounded portions 20, 22. The welding surface 26 therefore constitutes a portion to be cleaned 27 comprising residues of sealing film and glue.

[0050] Other containers may be treated within the scope of the invention, for example containers having a horizontal weld surface without a drooping edge.

[0051] The invention proposes a machine 28 for cleaning reusable containers shown in Figures 4 to 7. [Fig.5] shows an upstream part of the machine 28 comprising: - means 30 for conveying the containers 10 capable of conveying the reusable containers 10 to an abrasion station 32, - means 34 for holding the containers 10 designed to hold the containers 10 during abrasion.

[0052] In the example shown, the means 30 for conveying containers 10 comprise a belt conveyor 36.

[0053] As seen in [Fig.4], the belt conveyor 36 consists of the following elements: - a belt 38 for transporting the containers 10, the transport belt 38 being for example a plastic mat, the belt 38 extending mainly in a horizontal plane, - a chassis 40 comprising sliding portions or carrier rollers 42 with a transverse axis on which the transport belt 38 rests, - a return drum 44 with a transverse axis, located at the head of the conveyor 36, - a motor group 46 for driving the belt 38 having a transverse axis of rotation located at the tail of the conveyor 36, - transverse axis rollers or belt return rollers 48 in the lower part of the conveyor 36, and - a 50 band tension system.

[0054] According to an improvement of the machine 28 shown in [Fig.4], the transport belt 38 may include holding stops 52 so as to hold each container in a dedicated location on the belt 38 of the conveyor 36. For example, the conveyor 36 may be equipped with a trough belt making it possible to wedge the containers 10.

[0055] The means 34 for holding the containers 10 comprise, for example: - an upper roller 54 free to rotate or driven in rotation around a transverse axis 56 by a motor 58, the upper roller 54 being located above the transport belt 38, and - a rough cloth 60 driven by the upper roller 54 and placed at a distance corresponding to a height of container 10 from the conveyor belt 38, so that when a container 10 is placed between the rough cloth 60 and the conveyor belt 38, the rough cloth 60 adheres to the container 10 and drives it in a longitudinal translational movement towards the front, tangent to the cloth 60.

[0056] An adjustment of the holding means 34 in height, that is to say along the vertical axis, makes it possible to adapt the holding means 34 to the height of the container 10 and to manage the pressure exerted on the container 10 during the treatment.

[0057] Alternatively, the upper roller 54 could rotate about a vertical or oblique axis.

[0058] Alternatively, the machine 28 could comprise different conveying 30 and holding 34 means. The conveying 30 and holding 34 means can be combined in a system comprising housings for the containers 10 allowing both the transport and the holding of the containers 10. For example, according to an embodiment not shown, the conveying means 30 can be transfer wheels rotating around a vertical axis and comprising housings for receiving the containers on the periphery of the wheel.

[0059] The machine 28 further comprises an abrasion station 32 shown in figures 4, 6 and 7 allowing the removal of glue and film residues from the portion to be cleaned of the container 10. The abrasion station 32 comprises flexible abrasive elements 62. The term flexible is understood to mean deformable upon contact with a container 10.

[0060] In the example shown, the flexible abrasive elements 62 are carried by rotating brushes 64 which can rotate around a vertical axis 66. As a variant, the rotating brushes 64 could rotate around a horizontal or oblique axis.

[0061] Each rotary brush 64 consists of a head 68 and abrasive lamellae 70 attached to the head 68. The abrasive lamellae 70 extend in radial planes. The abrasive lamellae 70 are, for example, thin metal blades extending downwardly from the head 68 of the rotary brush 64, the metal blades being tightly located along three concentric circles centered on the axis 66 of rotation of the rotary brush 64. The abrasive lamellae 70 constitute flexible abrasive elements 62. The flexible nature of the abrasive lamellae 70 is imparted by the thinness of the abrasive lamellae 70.

[0062] Each rotating brush 64 has a rotational movement around a vertical axis, the rotational movement being able to be reversed during the cleaning of a container 10.

[0063] The rotating brushes 64 comprise a height adjustment means making it possible to adapt the abrasion station to the height of the containers 10 and to adjust the pressure exerted by the abrasive strips 70 on the portion of the container 10 to be cleaned.

[0064] The rotating brushes 64 are mounted to move in translation in a transverse back-and-forth movement. The transverse movement of the rotating brushes 64 is motorized in a back-and-forth movement. Thus, during the cleaning of the same container 10, the rotating brushes 64 move transversely to the left and then to the right along the portion to be cleaned.

[0065] Furthermore, the abrasion station 32 comprises two transverse rows 72, 74, including a first row 72 and a second row 74. Each row 72, 74 comprises a transverse alignment of several rotating brushes 64.

[0066] Each rotating brush 64 of the first row 72 is longitudinally aligned with a rotating brush 64 of the second row 74.

[0067] According to a variant not shown, each row 72, 74 can be reduced to a single rotating brush 64, the abrasion station 32 then comprising only two rotating brushes 64 following one another longitudinally.

[0068] Within a longitudinal alignment of two rotating brushes 64, the rotating brush 64 of the first row 72 and the rotating brush 64 of the second row 74 have an opposite direction of rotation.

[0069] Alternatively, the rotating brushes 64 of the first row 72 and the rotating brushes 64 of the second row 74 could be arranged in a staggered pattern.

[0070] According to other embodiments of the invention, the flexible abrasive element 62 could be a horizontal axis roller covered with a flexible abrasive cloth, or a flexible rough surface, or a brush comprising abrasive bristles. The flexible abrasive element 62 could be fixed relative to the cleaning machine 28, the relative movement between the container 10 and the flexible abrasive element 62 being imparted by the conveying means 30. According to another alternative, the abrasive element 62 could have any combination of movement among a horizontal axis rotation, a vertical axis rotation, a translation in the horizontal plane.

[0071] In particular, the holding means 34 comprising the rough cloth 60 can participate in the abrasion of the residues 24 of film and glue present on the portion to be cleaned 27 of the container 10.

[0072] According to another embodiment of the invention, the abrasion station 32 could comprise means for carrying out abrasion by sandblasting and / or by micro-blasting.

[0073] According to an improved embodiment, the machine 28 can be integrated within an installation 76 for cleaning reusable containers 10.

[0074] [Fig.8] represents a flowchart of an embodiment of such an installation 76.

[0075] The installation 76 comprises, for example, the succession of the following stations: - a pre-wash station 78 comprising means for removing any remaining contents from the containers 10, - a drying station 80 comprising means for drying the containers 10, - an abrasion station 32 present within the machine 28 described above, - a cleaning station 82 for cleaning the containers so as to make them suitable for food use again.

[0076] The conveying means 30 are designed to transport the containers from one station to another.

[0077] The installation may also include means for chemically attacking film residues.

[0078] Alternatively, the installation may only include some of the positions mentioned above. Preferably, the elements of the installation are made of stainless steel for the metal parts in order to avoid any risk of oxidation.

[0079] The invention also relates to a method for cleaning reusable containers 10 by means of a cleaning machine 28 or a cleaning installation as presented previously.

[0080] A flowchart of the method according to one embodiment of the invention is shown in [Fig.9]. In this embodiment, the method comprises two optional preliminary steps PI and P2 then four central steps E1 to E4 and finally two optional final steps F1 and F2.

[0081] The first central step E1 corresponds to the placement of a container 10 to be cleaned on conveying means 30. In this first central step E1, an operator places a container 10 on the transport belt 38 of the conveyor 36 at the entrance to the machine 28.

[0082] The second central step E2 corresponds to the routing of the container 10 by the conveying means 30 to the abrasion station 32. In this second central step E2, the conveying belt 38 transports the container 10 from the inlet of the machine 28 to a position located under the first row 72 of rotating brushes 64. The second central step E2 comprises, for example, holding the container 10 by means of the rough cloth 60 driven by the upper roller 54, so that when the container 10 is placed between the rough cloth 60 and the conveying means 30, the rough cloth 60 adheres to the container 10 and drives it in a longitudinal translational movement.

[0083] The third central step E3 corresponds to the removal of film residues 24 by abrasion using a flexible abrasive element 62 of the abrasion station 32. This third central step E3 comprises bringing the portion to be cleaned 27 into contact with at least one rotating brush 64 with a vertical rotation axis, the vertical axis being substantially orthogonal to the portion to be cleaned. In this third central step E3, the rotating brush 64 used comprises abrasive strips 70 extending in radial planes. The friction of the abrasive strips 70 against the surface to be cleaned 27 of the container 10 allows the removal of glue and film residues 24 by abrasion. This third central step E3 may comprise a height adjustment of the rotating brushes 64 to adjust the pressure exerted by the abrasive strips 70 on the surface to be cleaned 27.During the third central step E3, the transport belt 38 of the conveyor 36 continues to advance the containers 10 in a longitudinal movement. Thus, the containers 10 pass successively under rotating brushes 64 of the first row 72 and under rotating brushes 64 of the second row 74, the direction of rotation of the rotating brushes 64 being reversed between the first row 72 and the second row 74.

[0084] The fourth central step E4 corresponds to the ejection of the containers 10 from the abrasion station 32. Once the containers 10 have been conveyed under the first row 72 then under the second row 74 of rotating brushes 64, the transport belt 38 transports the containers 10 to the exit of the machine 28, out of the abrasion station 32. For example, the containers 10 fall at the exit of the conveyor 36 into a box.

[0085] According to an improvement of the method, the method may comprise the following preliminary steps carried out in this order and upstream of the first step E1 of placing a container 10 to be cleaned on conveying means 30.

[0086] The first preliminary step PI corresponds to the pre-washing of the containers 10. In this first preliminary step PI, the containers are placed in a pre-washing station 78 in which the containers are freed from any remaining contents. This first preliminary step PI may include a projection of jets of liquid solution onto the containers 10, a soaking and / or the passage into an enclosure comprising a high temperature solution in liquid or vapor form.

[0087] The second preliminary step P2 corresponds to the drying of the containers. In this second preliminary step P2, the containers are placed in a drying station 80 in which the containers 10 are dried, for example, by means of a blast of hot air.

[0088] The method may also be completed by a first final cleaning step F1. In this first final step F1, the container 10 is placed in the cleaning station 82 in which the container 10 is cleaned so as to make it suitable for food use again. This first final step F1 may include spraying jets of liquid solution onto the containers 10, soaking and / or passing through an enclosure containing a high-temperature solution in liquid form or in vapor form.

[0089] The method can also be finalized by a second final drying step F2 in which the containers 10 are dried, for example, by means of a blast of hot air.

[0090] Advantages of the invention are presented in the following.

[0091] The cleaning installation 76 is relatively simple and represents a rather low investment cost. Thus, the cost of washing the containers is controlled, which makes it possible to encourage the development of the container reuse circuit.

[0092] The drying step makes it possible to preserve the elements of the installation when these are made of steel which can oxidize and which risks aging badly in contact with projections and residual humidity on the containers.

[0093] The method of the invention makes it possible to guarantee a clean welding surface, free of any film or glue residue in order to ensure subsequent welding of a packaging film without risk of leakage. Indeed, the packaging represents a low environmental cost in comparison with the product it contains. Welding a packaging film without risk of leakage makes it possible to guarantee the protection of the product by the packaging to prevent the product from becoming unfit for consumption.

[0094] The method of the invention therefore makes it possible to reuse containers and makes it possible to reduce the production of waste linked to the packaging of products.

[0095] Legend

[0096] 10 containing 12 background 14 side wall 16 top edge 18 ledge 20 first rounding 22 second rounding 24 residues 26 welding surface 27 portion to clean 28 container cleaning machine 30 means of transport 32 abrasion station 34 means of maintenance 36 belt conveyor 38 transport belt 40 chassis 42 carrier rollers 44 drum 46 engine group 48 pebbles 50 belt tension system 52 holding stop 54 top roller 56 upper roller shaft 58 upper roller motor 60 rough canvas 62 soft abrasive element 64 rotating brush 66 rotating brush rotation axis 68 brush head 70 abrasive lamella 72 first row 74 second row 76 cleaning facility 78 pre-wash station 80 drying stations 82 cleaning station

Claims

Claims

1. Method for cleaning reusable containers (10) by means of a cleaning installation (76), the containers (10) comprising residues (24) of sealing film on a portion to be cleaned (27), the method comprising the following steps: - E1: placing a container (10) to be cleaned on conveying means (30), - E2: conveying the container (10) by the conveying means (30) to an abrasion station (32), - E3: removing the residues (24) of film by abrasion by means of a flexible abrasive element (62) from the abrasion station (32), - E4: ejecting the containers (10) from the abrasion station (32).

2. Method for cleaning containers (10) according to claim 1, characterized in that step E3 of removing film residues (24) comprises bringing the portion to be cleaned (27) into contact with at least one rotating brush (64) with an axis (66) of rotation substantially orthogonal to the portion to be cleaned (27).

3. Method for cleaning containers (10) according to claim 2, characterized in that, in step E3 of removing film residues (24), the rotating brush (64) used comprises abrasive strips (70) extending in radial planes.

4. A method of cleaning containers (10) according to any one of claims 2 or 3, characterized in that in step E3 of removing film residues (24), the container (10) passes from a first row (72) of rotating brushes (64) to a second row (74) of rotating brushes (64), the direction of rotation of the rotating brushes (64) being reversed between the first row (72) and the second row (74).

5. Method for cleaning containers (10) according to the preceding claim, characterized in that it comprises a first preliminary step PI of pre-washing the containers (10) before step E3 of removing the residues (24).

6. Method for cleaning containers (10) according to the preceding claim, characterized in that it comprises a second preliminary step P2 of drying the container (10) after the first preliminary step PI of pre-washing the containers (10) and before the step E3 of removing the residues (24).

7. A method of cleaning containers (10) according to any one of the re- preceding claims, characterized in that step E2 of conveying the container (10) is carried out by a belt conveyor (36).

8. Method for cleaning containers (10) according to any one of the preceding claims, characterized in that step E2 of conveying the container (10) comprises holding the container (10) by means of a rough cloth (60) driven by an upper roller (54) rotating about a transverse axis (56) and placed at a distance corresponding to a height of the container (10) from the conveying means (30), so that when the container (10) is placed between the rough cloth (60) and the conveying means (30), the rough cloth (60) adheres to the container (10) and drives it in a longitudinal translational movement.

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