BACKGROUND

The present invention relates to a transport device and a method for transporting cans. The invention further relates to a treatment system for treating cans, wherein the treatment system comprises the aforementioned transport device.

US 2007/0256320 Al shows a drying apparatus comprising an oven drying chamber, through which containers, in particular metal beverage container cans are configured to pass through. The drying apparatus is for use with an in-line can producing apparatus and is configured to be located downstream of a washing apparatus. The drying apparatus is configured for removing water, chemicals, contaminants etc. from the cans prior to the further processing (e.g. printing) of the cans. The cans are supported on a Kevlar open mesh conveyor belt and a suction chamber is created to draw or attract the cans to the conveyor belt to increase the stability of the cans. The conveyor belt is arranged to return within the drying apparatus in order to conserve as much heat as possible .

US 2007/0256320 Al does not disclose how the cans are transferred into and out of the drying apparatus. Typically, the known drying apparatus forms a part of a can treatment line that further comprises vacuum gripping means which are arranged above the conveyor belt for retaining the cans by suction and thereby transferring said cans from the washing apparatus to a downstream station. The suction prevents that the cans topple over during the transfer.

SUMMARY OF THE INVENTION

A drawback of the conventional suction means is that they do not always reliably retain the cans. Also, the suction means are relatively complex and require suction ducts, a vacuum source, air filters and the like to operate correctly. All these components are prone to failure and require regular maintenance. Moreover, the conventional suction means can not be applied universally throughout the can treatment line, as some stations have conditions, such as excessive heat or moisture, in which the suction means do not function correctly.

It is an object of the present invention to provide a transport device and a method for transporting cans, wherein the quality and/or reliability of the transfer of the cans can be improved.

According to a first aspect, the invention provides a transport device for transporting cans in a conveyance direction, wherein the transport device comprises an upstream conveyor and a downstream conveyor downstream of the upstream conveyor in the conveyance direction, wherein the transport device further comprises a transition part in the conveyance direction between the upstream conveyor and the downstream conveyor and extending in a transverse direction perpendicular or substantially perpendicular to the conveyance direction, wherein the transition part has a width in the conveyance direction that is smaller than five centimeters.

Preferably, the width of the transition part is smaller than three centimeters. Alternatively, the width is smaller than or equal to half a diameter of a standard '202 Can ' . The transition part according to the invention has the width as specified above to ensure that a can travelling across said transition part can already be supported by the downstream conveyor before it completely leaves the upstream conveyor. Hence, the can is conveyed at all times during the transfer by either the upstream conveyor, the downstream conveyor or both. Consequently, the cans can be transferred across the transition part at a substantially constant velocity in the conveyance direction. In other words, the cans do not stop at the transition part, thus effectively obtaining a non-stop transfer. Because of the substantially constant velocity, the cans can be transferred in a relatively stable state, e.g. without any changes in direction or speed and/or without the risk of cans running into each other at the transition part. Hence, the quality and/or reliability of the transfer of the cans can be improved. Moreover, because the transition part is a passive component, it does not require active controls or additional means to function. Hence, the transition part is relatively maintenance free and less prone to failures.

In a further embodiment, the upstream conveyor and the downstream conveyor extend in a horizontal or substantially horizontal conveyance plane, wherein the transition part comprises a top surface that is parallel or substantially parallel to the conveyance plane. Hence, changes in direction when transferring the cans from the upstream conveyor onto the transition part and from the transition part onto the downstream conveyor can be prevented .

In a further embodiment thereof, the top surface lies flush or substantially flush with the conveyance plane. Consequently, the top surface can support the cans as they travel across the transition part in or substantially in the plane defined by the conveyors. This increases the stability of the cans and may thus reduce the risk of the cans toppling over. In a further embodiment, the top surface has a lower roughness than the upstream conveyor and the downstream conveyor. Consequently, it can be ensured that the friction exerted by the upstream conveyor onto the cans is greater than the friction experienced by said cans when travelling across the transition part. Thus, despite the friction at the transition part, the cans will continue to move in the conveyance direction towards and onto the downstream conveyor as long as they are still in contact with the upstream conveyor.

In a further embodiment, in the conveyance direction, the upstream conveyor and the downstream conveyor comprise a head member and a tail member, respectively, wherein the transition part is situated between the head member and the tail member in the conveyance direction. Hence, the transition part can be sandwiched between the upstream conveyor and the downstream conveyor .

In a further embodiment thereof, the head member and the tail member are undriven . When said head member of the upstream conveyor and said tail member of the downstream conveyor are undriven members, they can be limited in terms of diameter. Consequently, the space between the conveyors, and as a result also the width of the transition part, can be reduced and/or minimized.

In a further embodiment, the transition part comprises a first side surface facing upstream in the conveyance direction, wherein the first side surface is recessed or concave. Preferably, the first side surface matches or substantially matches a radius of the upstream conveyor at the head member. Hence, the transition part can be positioned closer to upstream conveyor, thereby reducing any gaps between the transition part and said upstream conveyor and thus improving the stability of the cans during the transfer.

In a further embodiment, the transition part comprises a second side surface facing downstream in the conveyance direction, wherein the second side surface is recessed or concave. Preferably, the second side surface matches or substantially matches a radius of the downstream conveyor at the tail member. Hence, the transition part can be positioned closer to downstream conveyor, thereby reducing any gaps between the transition part and said downstream conveyor and thus improving the stability of the cans during the transfer.

In a further embodiment, the upstream conveyor and the downstream conveyor are conveyor belts. The conveyor belts may comprise one or more endless elements or loops that can form a flat or substantially flat upper run of the respective conveyor belt, which improves the stability of the cans transported on said conveyor belt.

In a further embodiment, the upstream conveyor and the downstream conveyor are link conveyor belts, wherein each link conveyor belt comprises a plurality of links which are interconnected to form a transport surface, wherein each link comprises an external surface for supporting the cans and an internal surface that runs over the respective head member or tail member, wherein the internal surface is recessed or concave. The recessed or concave internal surface of each link can reduce the so- called ^" 'polygon effect' and allow the head member and the tail member to be placed closer to the transition part. Hence, the length or width of the transition area in which the cans are transferred from the upstream conveyor, across the transition part and onto the downstream conveyor can be kept as small as possible.

In an embodiment thereof, the head member and/or the tail member define a return radius around which the links are returned between an upper run and a lower run of the respective conveyor, wherein the internal surface has a concave curvature that is equal to or substantially equal to the return radius. The internal surface of the links can therefore accurately follow the return radius, thereby minimizing the polygon effect. In a further embodiment thereof, the external surface is flat or substantially flat. Hence, in the upper run of the upstream conveyor or the downstream conveyor, the links can together form a flat or substantially flat transport surface for the cans .

According to a second aspect, the invention provides a treatment system for treating cans, wherein the treatment system comprises a transport device according to the present invention, wherein the treatment system further comprises two or more zones having or arranged for creating different environmental conditions, and one or more boundaries, wherein each boundary is located between a respective pair of the zones, wherein the transport device is arranged for transporting the cans through the two or more zones in the conveyance direction, wherein the treatment system comprises one or more of the transition parts, wherein each transition part in the conveyance direction is located within one meter from a respective one of the one or more boundaries.

The transition parts according to the second aspect are functionally equivalent to the previously described transition part according to the first aspect of the invention. In other words, the transition parts may comprise the same features as any one of the previously discussed embodiments. By providing one or more of the transition parts at or near one or more of the boundaries, the transport device can be divided in several upstream and downstream conveyors, each on a respective side of the transition part. Consequently, said conveyors do not extend far beyond the respective boundaries and can be contained within a respective one of the zones. This is particularly relevant when the environmental condition in one of the zones is to be separated from the adjacent zones, e.g. when containing heat or toxic substances, such as detergents. The transition parts at each of the one or more boundaries ensures that the cans can be reliably transferred across each boundary without toppling over. In an embodiment thereof, each transition part in the conveyance direction is located within fifty centimeters from a respective one of the boundaries, preferably within thirty centimeters from a respective one of the boundaries and most preferably within twenty centimeters from a respective one of the boundaries. The closer the transition part is to the boundary, the lesser the risk of one zone contaminating an adjacent zone.

In a further embodiment, in at least one of the two or more zones the environmental condition is the presence of a medium. Preferably, at least one zone of the two or more zones is a drying zone in which the medium is a drying medium, preferably superheated steam. Heat generated by the superheated steam can easily escape by heat-exchange through the conveyors that run in and/or out of the drying zone. Typically, a boundary is created by providing a housing. By providing a transition part at or near said housing, the upstream conveyor can be separated from the downstream conveyor, thereby preventing heat loss across the boundary via one of said conveyors.

In a further embodiment, at least one zone of the two or more zones is a first washing zone in which the medium is a first washing medium. Preferably, at least one zone of the two or more zones is a second washing zone in which the medium is a second washing medium, different from the first washing medium. More preferably, one of the first washing medium and the second washing medium comprises a detergent . By providing the transition part at or near the boundary of the first washing zone and/or at or near the boundary between the first washing zone and the second washing zone, it can be prevent that one of the upstream conveyor and the downstream conveyor carries residual washing medium out of a respective one of the zones. This is particularly relevant when working with toxic substances, such as detergents.

In a further embodiment thereof, the other one of the first washing medium and the second washing medium comprises water without additives. By preventing that waste water escapes from the respective zone via one of the conveyors, more water can be recycled and/or the water efficiency of the overall system can be improved.

In a further embodiment, at least one zone of the two or more zones is an ambient zone in which the environmental condition is equal to or substantially equal to a surrounding ambient condition of the treatment system. In the same way that the transition part facilitates a separation of zones, the transition part can also be located between a conditioned zone and an ambient zone, e.g. at the input side or output side of the treatment system.

In a further embodiment, the treatment system comprises one or more barriers for separating the two or more zones, wherein the one or more barriers each form a respective one of the one or more boundaries. Said barriers can form a physical boundary between a respective pair of the two or more zones. By arranging the transition part at or near said one of said one or more barriers, the upstream and downstream conveyors can be effectively separated at or near said one or more barriers, thereby obtaining the same advantages as described in relation to the one or more boundaries .

Preferably, at least one of the one or more barriers is a wall that is arranged above the transport device. More preferably, the treatment system comprises a housing surrounding at least one of the two or more zones, wherein the wall is a part of the housing. Such a housing may for example be used to contain the aforementioned superheated steam. Hence, the risk of heat loss through the conveyors is greatest at the barrier defined by said housing and the transition part can be arranged at or near said housing.

Additionally or alternatively, the treatment system further comprises a drip tray below at least one of the two or more zones, wherein at least one of the one or more barriers is formed by the drip tray. Said drip tray may be use to collect and/or contain the aforementioned washing medium in a respective one of the washing zones. As the risk of conveyors carrying residual washing medium across the zone is greatest near the barrier formed by the drip tray, the transition part should be arranged at or near said barrier, preferably upstream of said barrier within the drip tray in the conveyance direction.

According to a third aspect, the present invention provides a method for conveying a can using a transport device according to the present invention, wherein the method comprises the steps of:

a) conveying the can in the conveyance direction on the upstream conveyor onto the transition part such that the can is partially supported on said transition part and partially supported by the upstream conveyor;

b) further conveying said can on the upstream conveyor in the conveyance direction onto the downstream conveyor such that the can is partially supported on said downstream conveyor and, simultaneously, partially supported on the upstream conveyor;

c) further conveying the can in the conveyance direction on the downstream conveyor.

The method relates to the practical implementation of the transport device according to the first aspect of the invention and thus has the same technical advantages, which will not be repeated hereafter.

In an embodiment thereof, the can is continuously driven by either the upstream conveyor or the downstream conveyor or both during conveyance across the transition part .

In a further embodiment thereof, the can is driven in the direction of conveyance from the upstream conveyor, across the transition part and onto the downstream conveyor at a constant speed. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of an exemplary embodiment shown in the attached schematic drawings, in which:

figure 1 shows an isometric view of a treatment system for treating cans according to a first embodiment of the invention;

figure 2 shows a cross-section of the treatment system according to the line II-II in figure 1;

figure 3 shows a view of a detail of the treatment system according to the circle III in figure 1;

figure 4 shows a side view of the detail of the treatment system according to figure 3;

figure 5 shows a top view of a support to be used in the treatment system according to figure 2;

figure 6 shows an isometric view of an alternative support to be used in a treatment system according to the invention; and

figure 7 shows a cross-sectional view of an alternative treatment system for treating cans.

DETAILED DESCRIPTION OF THE INVENTION

Figures 1 and 2 show a treatment system 1 for treating cans according to a first exemplary embodiment of the present invention. In this particular embodiment, the treatment system 1 comprises a drying device suitable for carrying out a method for drying metal cans 9.

As shown in figures 1 and 2, the treatment system 1 comprises a housing 2 that forms a drying zone Z4 for receiving the cans 9. The drying zone Z4 is arranged to be conditioned. In particular, the treatment system 1 is arranged for creating an environmental condition in the drying zone Z4 suitable for drying the cans 9. As shown in figure 2, the treatment system 1 comprises two first inlet openings 23 and two first outlet openings 24 in the housing 2 for supplying and discharging a drying medium S. Preferably the first inlet openings 23 are each provided with a nozzle (not shown) for evenly distributing the drying medium within the drying zone Z4. In other words, the environmental condition in the drying zone Z4 is the presence of a medium, in particular the drying medium. Preferably, the drying medium S is superheated steam.

The housing 2 surrounds the drying zone Z4. The outside of the housing is an ambient zone Z5 having different environmental conditions than the drying zone Z4. In the ambient zone Z5, the environmental condition is equal to or substantially equal to a surrounding ambient condition of the treatment system 1. For maintaining an effective separation between the drying zone Z4 and the ambient zone Z5, i.e. the surroundings of the treatment system 1, the passage openings 21, 22 are as small or as low as possible and/or the passage openings 21, 22 may be provided with an air curtain (not shown) .

The treatment system 1 further comprises a transport device 4 for conveying the cans 9 in a conveyance direction X through the drying zone Z4. The treatment system 1 comprises a first passage opening 21 and a second passage opening 22 in the housing 2 for passing cans 9 through in a continuous process in the conveyance direction X from outside of the housing 2 towards the drying zone Z4 inside the housing 2 and from the drying zone Z4 to outside of the housing 2. The housing 2 further comprises a wall 25 facing downstream in the conveyance direction X. The wall 25 is arranged above the transport device 4 and at least partially forms the second passage opening 22. The wall 25 forms a barrier for separating the drying zone Z4 and the ambient zone Z5. In other words, said wall 25 forms the boundary B5 between the drying zone Z4 and the first ambient zone Z5. The second passage opening 22 coincides with said boundary B5. The drying device 1 is configured for allowing the medium S to flow in the drying zone 20 from the inlet openings 23 past the cans 9 to the outlet openings 24. Due to the convective heat transfer between the medium S and the cans 9, the cans 9 will heat up rapidly to a temperature at which moisture present on the walls of the cans 9 will evaporate.

As shown in figures 1 and 2, the transport device 4 is configured for leading the cans 9 in the conveyance direction X from outside of the drying zone Z4 to inside of the drying zone Z4 and from the drying zone Z4 to the outside of the drying zone Z4. In particular, the transport device 4 is configured for moving the cans 9 in the conveyance direction X successively through the first passage opening 21 and the second passage opening 22. The cans 9 can be led through the drying zone Z4 in batches or in a continuous process.

The transport device 4 according to the embodiment shown in figures 1 and 2 comprises a first conveyor 41 and a second conveyor 42, downstream of the first conveyor 41 in the conveyance direction X. In other words, the first conveyor 41 is an upstream conveyor and the second conveyor 42 is a downstream conveyor. As shown in figure 2 the first conveyor 41 and the second conveyor 42 extend in the conveyance direction X in a horizontal or substantially horizontal conveyance plane P for supporting the cans 9.

In the exemplary embodiment as shown, the conveyors 41, 42 are conveyor belts, i.e. a conveyor comprising one or more pulleys or shafts and one or more carrying means, i.e. wires or belts, that are arranged in endless loops around said one or more pulleys or shafts to form an endless transport surface. The conveyors 41, 42 may for example be wire conveyors, mesh conveyors or closed belt conveyors. In this exemplary embodiment, the conveyors 41, 42 are linked belt conveyors, as shown in figure 4. Said linked belt conveyors are also known as chain conveyors or shackle conveyors. The linked belt conveyors 41, 42 each comprises an carrying means formed by a plurality of interconnected chain elements, shackles or links 7.

From a point upstream in the conveyance direction X, the first conveyor 41 extends relative to the first passage opening 21 in the conveyance direction X up to the second passage opening 22 for introducing the cans 9 into and passing them through the drying zone Z4. As the first conveyor 41 is situated at least partly in the drying zone Z4, it is exposed to high temperatures. For that reason, the first conveyor 41 is configured as a heat-resistant conveyor. Preferably, the first conveyor 41 is a water-permeable conveyor.

The second conveyor 42 is arranged outside of the housing 2, downstream from the second passage opening 22, in the conveyance direction X. As the second conveyor 42 is arranged outside of the housing 2 and separate from the first conveyor 41, it can be counteracted that it heats up in the drying zone Z4 and heat losses can be kept to a minimum. As the second conveyor 42 is not exposed to the high temperatures in the drying zone Z4, it can be a less complex and/or less costly conveyor than the first conveyor 41.

Figure 3 shows a detail of the transition area between the first conveyor 41 and the second conveyor 42. In this transition area the transport device 4 comprises a transition part 5 for bridging the distance between the first conveyor 41 and the second conveyor 42 in the conveyance direction X. The transition part 5 is arranged in the conveyance direction X between the first conveyor 41 and the second conveyor 42. The transition part 5 extends in a transverse direction Y perpendicular or substantially perpendicular to the conveyance direction X. In particular, the transition part extends in the conveyance plane P in the transverse direction Y. The transition part 5 has a width W in the conveyance direction that is smaller than five centimeters. Preferably, the width W of the transition part 5 is smaller than three centimeters. Alternatively, the width W of the transition part 5 is smaller than or equal to half a diameter of a standard '202 Can' . Such a ^Λ 202 Can' has a standardized base diameter of approximately sixty-six millimeters. Hence, half the diameter equals thirty-three millimeters .

The transition part 5 is located in the conveyance direction X within one meter from the boundary B5 between the drying zone Z4 and the first ambient zone Z5, preferably, within fifty centimeters, more preferably within thirty centimeters and most preferably within twenty centimeters. The transition part 5 comprises a top surface 53. The top surface 53 is flat or substantially flat. Optionally, the top surface 53 is provided with slightly rounded or chamfered edges, as shown in figure 4, to prevent that the transition part 5 bites into the side of the cans 9 as the cans 9 travel across the transition part 5. The top surface 53 extends over the width W in the conveyance direction X. The top surface 53 is parallel or substantially parallel to the conveyance plane P. In particular, the top surface 53 lies flush or substantially flush with the conveyance plane P.

Preferably, the top surface 53 has a lower roughness than the first conveyor 41 and the second conveyor 42.

The first conveyor 41 and the second conveyor 42 in the conveyance direction X comprise a head member 47 and a tail member 48, respectively, at the location where the upper run or conveyance run of the respective conveyors 41, 42 change into the lower run or return run. The transition part 5 is arranged between the head member 47 and the tail member 48. In other words, the transition part is situated between the head member 47 and the tail member 48 in the conveyance direction X. Preferably, the head member 47 and the tail member 48 are rolls, toothed wheels or gear wheels. Most preferably, the head member 47 and the tail member 48 are undriven shafts. Alternatively, the head member 47 and the tail member 48 may be formed by non-rotating nose bars or the rounded edges of a support plate. Hence, the shafts 47, 48 can be smaller than the driven shafts. By keeping the head shaft 47 and the tail shaft 48 as small as possible, the distance between the first conveyor 41 and the second conveyor 42, and as a consequence the width of the top side 53 of the transition part 5 as well, can be kept as small as possible.

The transition part 5 comprises a first side surface 51 facing upstream in the conveyance direction X. The first side surface 51 is recessed or concave. In particular, the first side surface 51 has a concave curvature that matches or substantially matches a radius Rl of the first conveyor 41 at the head member 47. Similarly, the transition part 5 comprises a second side surface 52 facing downstream in the conveyance direction X. The second side surface 52 is recessed or concave. In particular, the curvature of the second side surface 52 matches or substantially matches a radius R2 of the second conveyor 42 at the tail member 48.

As shown in figure 4, each link 7 in the first conveyor 41 and the second conveyor 42 has an external surface 71 for supporting the cans 9 and an internal surface 72 that runs over the head member 47 and the tail member 48, respectively. Each link 7 has two hinge ends 73 for connecting said link 7 to the other links 7 in the chain. Preferably, the external surface 71 of each link 7 is flat or substantially flat between the hinge ends 73, such that the links 7 in the conveyance run or upper run of the first conveyor 41 and the second conveyor 42 can form a flat or substantially flat transport surface that is flush with the transport plane P. However, as the links 7 of the first conveyor 41 and the second conveyor 42 travel around the head member 47 and the tail member 48, respectively, their external surfaces 71 tend to form a slightly polygonal surface. This is known as the polygonal effect' or polygonal action' in link conveyor belts. For the external surfaces 71, this polygonal effect is not considered to be a problem, as it is inherent to their function of forming a transport surface that is as flat as possible in the upper run.

If the internal surfaces 72 of the links 7 would be just as flat as the external surfaces 71, the same polygonal effect would occur on the inside of the conveyors 41, 42. However, as the internal surfaces 72 of the links directly contact the head member 47 or the tail member 48, the polygon effect would cause the links 7 to be pushed away from the respective member 47, 48 and cause a varying radius of the respective conveyor 41, 42 around the respective member 47, 48.

In other words, said links 7 would not accurately follow the curvature of the head member 47 and the tail member 48 and may increase the diameter of the first conveyor 41 and the second conveyor 42 at the head member 47 and the tail member 48, respectively. Consequently, when using the conveyors 41, 42 on either side of the transition part 5, the head member 47 and the tail member 48 may not be positioned as close as possible to the transition part 5 and the distance between the conveyors 41, 42 may exceed the diameter of the cans 9. Moreover, the polygonal effect may cause the links 7 to briefly tilt upwards out of the conveyance plane P before disappearing in the gap between the transition part 5 and the head member 47 or the tail member 48. Said tilting could cause the cans 9 to topple over.

To solve the above issues, the internal surface 72 of each link 7 has been provided with a recess or a concave curvature that allows said link 7 to more accurately and/or more closely follow the curvature of the head member 47 or the tail member 48.

In particular, the head member 47 and the tail member 48 define a return radius R3 around which the links 7 are returned between the upper run and the lower run of the respective conveyor 41, 42. The internal surface 72 of each link 7 has a concave curvature with a diameter that is equal to or substantially equal to the return radius R3. The internal surface 72 extends concavely between the hinge ends 73 of the link 7. Consequently, the link 7, when supported on the head member 47 or the tail member 48, has a thickness D in the radial direction of said head member 47 or tail member 48 that is the greatest at the respective hinge ends 73 and decreases towards the center of the link 7 between the respective hinge ends 73. Preferably, the sum of the return radius R3 of the head member 47 or the tail member 48 and the thickness D of the link 7 at the hinge ends 73 in the radial direction defines the radius Rl, R2 of the respective conveyor 41, 42 around the respective member 47, 48. More preferably, the transition part 5 is positioned in such a way between the first conveyor 41 and the second conveyor 42 that the first side surface 51 and the second side surface 52 extend at the first radius Rl of the first conveyor 41 and at the second radius R2 of the second conveyor 42, respectively .

Figure 7 shows an alternative treatment device 101 according to the present invention. The alternative treatment system 101 comprises five zones Zl, Z2, Z3, Z4, Z5. The zones Zl, Z2, Z3, Z4, Z5 have or are arranged for creating different environmental conditions. The alternative treatment system 101 comprise one or more boundaries Bl, B2, B3, B4, B5. Each of said boundaries Bl, B2, B3, B4, B5 is located between a respective pair of the zones Zl, Z2, Z3, Z4, Z5.

The alternative treatment device 101 further comprises an alternative transport device 104 for transporting the cans 9 in the conveyance direction X. The alternative transport device 104 is provided with a first conveyor 141 and a second conveyor 142 downstream in the conveyance direction X of the first conveyor 141. The alternative transport device 104 further comprises a third conveyor 143 downstream in the conveyance direction X of the second conveyor 142, a fourth conveyor 144 downstream in the conveyance direction X of the third conveyor 143 and a fifth conveyor 145 downstream in the conveyance direction X of the fourth conveyor 144. The conveyors 141, 142, 143, 144, 145 extend substantially in the conveyance plane P .

The alternative transport device further comprises transition parts 5 similar or functionally equivalent to the previously discussed transition part 5. Each transition part 5 is located at or near a respective one of the boundaries B1-B5. Each transition part 5 is located in the conveyance direction X between a respective upstream conveyor 141, 142, 143, 144 and a respective downstream conveyor 142, 143, 144, 145.

In this particular embodiment, the alternative treatment system 101 comprises two ambient zones Zl, Z5. In the ambient zones Zl, Z5, the environmental condition is equal to or substantially equal to a surrounding ambient condition of the alternative treatment system 101.

The alternative treatment system 101 comprises a first washing zone Z2 in which the medium is a first washing medium. In this embodiment, the alternative treatment system 101 further comprises a second washing zone Z3 in which the medium is a second washing medium different from the first washing medium. Alternatively, the alternative treatment system 101 may only comprise a single washing zone Z2, in which case it is directly followed by a different non-washing zone. In this particular embodiment, the first washing medium comprises a detergent for chemically washing the cans 9. The second washing medium is plain water or water without additives for washing and/or rinsing of the cans 9.

In this exemplary embodiment, the alternative treatment system 101 comprises a first drip tray 61 and a second drip tray 62 arranged below the alternative transport system 104 for collecting waste medium in the first washing zone Z2 and the second washing zone Z3, respectively. The drip tray 61 is arranged below the first washing zone Z2. In this particular example, the boundary Bl between the ambient zone Zl and the first washing zone Z2 and the boundary B2 between the first washing zone Z2 and the second washing zone Z3 are formed by the dripping tray 61 and/or the second drip tray 62.

As shown in figure 2, the transport device 4 further comprises a support 8 for supporting the first conveyor 41. As is best shown in figure 5, the support 8 comprises carriers 81, first girders 82 and second girders 83. The carriers 81 extend in the conveyance direction X or substantially parallel to the conveyance direction X and support the first girders 82. The first girders 82 extend perpendicular or substantially perpendicular to the conveyance direction X between the carriers 81, whereas the second girders 83 are arranged in a herringbone pattern on the first girders 82 and between the carriers 81. The second girders 83 rest on the first girders 82. On the side facing away and/or facing upward from the first girders 82, the second girders 83 form a support plane for supporting the first conveyor. The support plane runs parallel to the conveyance plane P. In this example the first conveyor 41 is a metal conveyor. On the side facing the support plane, the second girders 83 are provided with a synthetic layer for reducing the frictional resistance and wear at the location of contact with the metal first conveyor 41. Optionally, the second girders 83 are made entirely of synthetic material, provided that the synthetic material in question is suited to the conditions prevailing in the drying zone Z4. In this example the synthetic material is polytet rafluoroethylene (PTFE) .

Figure 6 shows an alternative support 208 for supporting a conveyor in the can washer 11. As the agents used for washing the cans often are caustic and/or corrosive, such a conveyor usually is a corrosion- resistant metal conveyor.

The alternative support 208 comprises carriers

281, first girders 282 and second girders 283. The carriers 281 extend in the conveyance direction X or substantially parallel to the conveyance direction X and support the first girders 282. The first girders 282 extend perpendicular or substantially perpendicular relative to the conveyance direction X and comprise recesses 280 for clamping the second girders 283. The second girders 283 are arranged in a herringbone pattern and are clamped in the recesses 280 of the first girders

282. On the side facing away from the first girders 282, the second girders 283 form a support plane E spaced apart from the first girders 282.

The second girders 283 preferably are formed by a plurality of individual synthetic strips 284. The synthetic strips 284 are standard and/or straight strips that together form the herringbone pattern. Due to the use of the synthetic material, wear in the support plane E between the metal conveyor and the second girders 283 can be kept limited. The synthetic strips can easily be placed in the recesses of the first girders 282. The synthetic strips 284 are kept in their positions merely by clamping and therefore there is no need for them to be interconnected or to connect them to one another. As a consequence, the synthetic strips 284 are relatively inexpensive compared to a specifically pre-shaped herringbone pattern or another pre-shaped pattern, because of which the costs of the alternative support 208 can remain low.

In a further alternative embodiment, the first conveyor may be a plastic conveyor.

A method for conveying a can 9 through the treatment system 1 according to figures 1-5 will be elucidated below.

Figures 1-4 show cans 9 on the first conveyor 41. The cans 9 are continuously conveyed in the conveyance direction X by said first conveyor 41. In particular, as shown in figure 3, one of the cans 9 is conveyed onto the transition part 5, such that said can 9 is partially supported on said transition part 5 and partially supported by the first conveyor 41. The can 9 is then further conveyed in the conveyance direction X onto the second conveyor 42, such that the can 9 is simultaneously partially supported by the first conveyor 41 and the second conveyor 42. Next, the can 9 is further conveyed in the conveyance direction X by the second conveyor 42 such that the can 9 is supported by the transition part 5 and the second conveyor 42. Eventually, the can 9 is further conveyed in the conveyance direction X by the second conveyor 42. Hence, the can 9 is continuously driven by either the upstream conveyor 41 or the downstream conveyor 42 or both during conveyance across the transition part 5. Preferably, the first conveyor 41 and the second conveyor 42 are driven at equal or substantially equal velocities in the conveyance direction. More preferably, the can 9 is driven at a constant speed in the conveyance direction X.

The cans 9 can be transferred in substantially the same manner across the transition parts as shown in figure 7, e.g. from the first conveyor 141 onto the second conveyor 142, from the second conveyor 142 onto the third conveyor 143, etc.

The above description is included to illustrate the operation of preferred embodiments of the invention and not to limit the scope of the invention. Starting from the above explanation many variations that fall within the scope of the present invention will be evident to a skilled person.