Vacuum sealing machine for cans and method for vacuum sealing cans

Abstract

The present invention discloses a vacuum sealing machine (1) for cans, comprising: platforms (3) that move along a closing station (EC), a vacuum station (EV) and an opening station (EA). At the closing station (EC), hoods (6) lower over the platforms (3), on which a can (100) is located with its lid (200) resting on said can. At the vacuum station (EV), a vacuum is applied to each hood (6), the vacuum reaching the inside of each can (100). At the opening station (EA), the hoods (6) lift causing each lid (200) to attach to the corresponding can (100) due to pressure. The invention also comprises a method that is carried out by said machine (1).

Description

[0001] VACUUM CAN SEALING MACHINE AND PROCEDURE FOR VACUUM SEALING CANS

[0002] DESCRIPTION

[0003] OBJECT OF THE INVENTION

[0004] The present invention belongs to the field of the food industry, and more specifically to the sealing of vacuum-sealed cans of preserved food.

[0005] A first object of the invention is a machine designed to vacuum seal cans, which can be made of tin or glass. That is, the same machine seals both tin and glass cans.

[0006] A second object of the invention is a new method for closing tin or glass cans using the above machine.

[0007] BACKGROUND OF THE INVENTION

[0008] Various models of canned goods are currently known, the closure of which is based primarily on the overlapping of the edge of the lid and the edge of the jar, both being pressed together by means of a roller. However, in this type of canned goods, the attachment of the lid to the body of the jar depends on the presence of a vacuum inside the jar. When the vacuum disappears, most of the lid's holding power disappears as well, and it can then be separated from the body of the jar by applying moderate manual force. To open this can, the consumer simply removes the adhesive film and, once the vacuum is lost, gently pull on the lid. International application PCT / ES2010 / 070345 is an example of this type of can.

[0009] Figs. 1a and 1b show an example of such a can. As can be seen, the can comprises a body (100) and a lid (200) with an opening (300) in the center. The lid (200) is only secured to the body (100) by the force exerted by the vacuum. To prevent the loss of vacuum through the opening (300), the opening is closed by means of an adhesive sheet (400). As shown in Fig. 1a, when the consumer opens the can, he only has to pull the adhesive sheet (400), so that the can (100) loses its vacuum. Then, as can be seen in Fig. 1b, the consumer can manually separate the lid (200) from the body (100) of the can without any problems.

[0010] This new type of canning jar is convenient and can be used to preserve a wide variety of foods. However, to date, there is no known way to attach the lid to the jar that is quick and easy enough.

[0011] DESCRIPTION OF THE INVENTION

[0012] The applicant of the present application has solved the above problems by means of a machine specifically designed for sealing this type of can solely by vacuum. The present invention also describes a method for sealing these cans, whether metal or glass. This machine is the only one on the market capable of sealing both types of containers.

[0013] First aspect: vacuum can sealing machine

[0014] A first aspect of the present invention relates to a vacuum can sealing machine configured to continuously vacuum seal metal and glass cans using corresponding lids. The lids are the same for both types of containers. This machine essentially comprises the following elements: a) Housing

[0015] This is a housing, which can be made of stainless steel, equipped with a can inlet and a lid inlet. The housing is usually essentially parallelepiped-shaped and may have several openings, usually closed by doors, to allow access to the interior for repair and maintenance work. b) Platforms

[0016] This is a plurality of individual platforms that move continuously along a closed path through a closing station, a vacuum station, and an opening station. For example, the platforms can be arranged on a mobile element, such as rail conveyors or the like, to move along the aforementioned stations. These stations are described in greater detail later in this document. c) First conveyor

[0017] This is a conveyor arranged at the can entrance to receive the cans, transport them, and deposit each of said cans on a corresponding platform. This conveyor can, in principle, be of any type as long as it receives the cans and deposits them on the platform in question. For example, in a particularly preferred embodiment of the invention, the first conveyor is a conveyor belt or similar.

[0018] In a preferred embodiment of the invention, the machine further comprises a star configured to transfer the cans from the end of the first conveyor to the corresponding platforms. A can presence detector determines whether there are any containers and, if so, a signal is sent to activate the second conveyor, which in response selects a lid from the accumulator. The selection of the lid for each can is thus carried out synchronously, with each lid falling onto a chute that accompanies each can to the platform. d) Second conveyor

[0019] The second conveyor is arranged at the lid inlet to receive the lids, transport them, and place each lid on a corresponding can. Like the first conveyor, it can be of any type as long as it has the capacity to receive the lids and place them on the cans, typically once the cans are already placed on the corresponding platform. For example, in a preferred embodiment of the invention, the first conveyor comprises a hopper along which the lids slide downward and are guided by a curve until they are placed on the cans.

[0020] At the top of the second conveyor is a steam-powered cap accumulator, so that the second conveyor descends following the aforementioned curve to a cap sorting tower. The cap tower is attached to a stainless steel table, which has guides at the bottom that center the cap in relation to the can placed on a corresponding platform. e) Closing station

[0021] The closing station constitutes a section of the path along which the platforms move, on which the cans are placed, with their corresponding lids resting on them and, naturally, already filled with the corresponding product. At the closing station, a plurality of bells descend toward the aforementioned platforms, such that a lower edge of each bell rests hermetically against an upper surface of the corresponding platform. Thus, a can with its lid resting on it remains inside each bell. The interior space of each bell, including the can and lid resting on each platform, is thus isolated from the space outside the platform.

[0022] To carry out the above steps, the bells are arranged on an upper base that rotates synchronously with the platforms. Once the can is placed on each platform with the lid resting on it, a lower cylinder raises the platform and an upper cylinder supports the bell, lowering it, fitting it tightly onto the platform. Preferably, each platform includes a sealing gasket made of an elastomeric material, such as rubber, to ensure tightness. f) Vacuum station

[0023] After passing through the closing station, where each bell is lowered onto a corresponding platform, the platforms pass through the vacuum station. At the vacuum station, once the bells are resting on their corresponding platform, a vacuum is applied to the interior of each bell by means of a vacuum system connected to the top of each bell. For example, the top of each bell may be connected via a conduit to a vacuum source. When the vacuum is applied, since the lid is resting on the can, the vacuum reaches the interior of each can. Furthermore, during this stage, the platform is raised slightly with the help of the lower cylinder, thus compressing the lid against the can as the base of the can rests on the platform and the lid rests on an upper part of the bell's interior.

[0024] In a preferred embodiment of the invention, the machine also comprises sensors to ensure that the closure has been carried out correctly. Specifically, there is a vacuum sensor located inside each chamber to check whether the desired vacuum has been reached during the vacuum application process, and a laser sensor that checks the bottom of the lid. Those cans that have not been closed correctly are preferably expelled from the third conveyor by means of a pneumatic cylinder to a rejection conveyor at the final end of which the defective cans accumulate. g) Opening station

[0025] Once past the vacuum station, where a vacuum is applied to each bell and a respective pusher closes each can with its lid, the platforms reach the opening station. At the opening station, each bell rises again to separate from the aforementioned platform, thus breaking the vacuum inside each bell. In this way, the vacuum previously created inside the can causes the corresponding lid to be pressure-fixed to that can. h) Exit of closed cans

[0026] Finally, the closed cans are transported by a third conveyor located past the opening station.

[0027] This innovative machine allows the described cans to be closed simply and efficiently by applying only a vacuum, without the need for threads or other systems to fasten the lid to the can.

[0028] In a particularly preferred embodiment of the invention, each assembly consisting of a platform, pusher, and bell is mounted to movement means that cause it to move continuously along said closed path. In this way, each assembly successively passes next to the ends of the first and second conveyors to receive the cans and lids. Next, each assembly passes: through the closing station, where the bells descend; through the vacuum station, where a vacuum is applied; and through the opening station where the bells ascend. Finally, each assembly passes next to one end of the third conveyor to remove the closed cans. Each assembly is then emptied again to receive another can and another lid when it again passes next to the ends of the first and second conveyors, thus beginning the cycle anew.The closed path may, in principle, have any shape, although in a preferred embodiment of the machine of the invention the path is essentially circular.

[0029] Second aspect: vacuum sealing procedure for cans

[0030] A second aspect of the present invention relates to a method for vacuum sealing cans using the above-mentioned machine. This method essentially comprises the following steps:

[0031] 1. Transport a boat from a boat ramp to a platform.

[0032] 2. Transport a lid from a lid inlet to place it on the jar.

[0033] 3. Lower a bell onto the platform so that a lower edge of the bell rests tightly on an upper surface of the platform, leaving the can with its lid placed on it inside the bell.

[0034] 4. Apply vacuum to the inside of the bell by means of a vacuum system connected to an upper end of the bell, reaching the inside of each can.

[0035] 5. Slightly raise the platform with the help of a lower cylinder, leaving the lid compressed against the can by resting the base of the can on the platform and the lid on an upper part of the interior of the bell, leaving an interior space of each can separated from a space outside the can.

[0036] 6. Raise the bell to separate it from the aforementioned platform, so that the vacuum created inside the can causes the corresponding lid to be fixed to the can by pressure.

[0037] 7. Transport the closed boat to a boat launch.

[0038] BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figs. 1a and 1b show an example of a vacuum-sealed can according to the prior art. Fig. 2 shows a perspective view of a machine according to the present invention.

[0040] Fig. 3 shows a plan view of a machine according to the present invention.

[0041] Figs. 4A-4D schematically show a sequence of steps in the can closing process carried out by the machine of the present invention.

[0042] PREFERRED EMBODIMENT OF THE INVENTION

[0043] A particular example of a machine (1) according to the invention is described below with reference to the attached figures.

[0044] Fig. 2 shows an exterior view of a machine (1) according to the present invention. As can be seen, the machine (1) comprises a housing (2) with an essentially rectangular shape and provided with a series of doors that allow access to its interior for maintenance. A can inlet (21) is arranged on a side face of the housing (2) to allow the introduction of the cans (100), which are transported by a first conveyor (4) to the interior of the machine (1). Similarly, at a higher point on the same side face of the housing (2) there is a lid inlet (22) provided with a conveyor (5) formed by a lid accumulation curve and which carries the lids (200) to the interior of the machine (1). On a side face of the housing (2) opposite the previous one, an outlet (23) for closed cans can be seen, to which the cans (100) already closed with their corresponding lid (200) arrive through a third conveyor (8).A rejection conveyor (14) can also be seen, through which defectively closed cans (100) are ejected.

[0045] Fig. 3 shows a top view of the inside of the machine (1) of the present invention. It can be seen that the first conveyor (4) through which the cans (100) introduced into the machine through the cap inlet (21) arrive at a first rotary distributor (10). The first rotary distributor (10), also called a star, has essentially semicircular cavities, and is located next to a guide piece (11) that has a circular shape parallel to the perimeter of the first rotary distributor (10). In this way, when a can (100) enters one of the cavities of the first rotary distributor (10), said can (100) is transported in a circular path pushed by the first rotary distributor (10) and guided by the circular wall of the guide piece (11) until it is deposited on a corresponding platform (3) right at the start of a closing station (EC).Although not seen in this figure, the second conveyor (5) transports the lids (200) from the lid inlet (22) until each lid (22) is deposited on a can (100). Thus, at the start of the travel of each platform (3) along the circular travel of the machine (1), a can (100) is deposited on the platform (3) and, in turn, a lid (200) is deposited on said can (100).

[0046] Once the container is placed on the platform (3), it begins its circular journey, which first passes through the closing station (EC), then passes through the vacuum station (EV), and finally passes through the opening station, from which it exits through the exit star (12) to the third conveyor (8) or the rejection conveyor (14).

[0047] Figs. 4A-4E show in greater detail the vacuum sealing process of the cans (100) implemented by the machine (1) of the present invention.

[0048] Fig. 4A shows an initial state at the beginning of the closing station (EC) where each can (100) has already been placed on the platform (3) with its lid (200) resting on it. As can be seen, the platform (3) is essentially a flat plate of essentially circular shape. Each platform (3) is supported by a cylinder (7) which, with the aid of a cam, can push the platform (3) slightly upwards.

[0049] On the other hand, in a position located vertically above the platform (3) there is a bell (6) having an open lower side with a flat edge (6¡) designed to rest completely on the platform (3). The platform (3) further has a gasket made of an elastomeric material to ensure tightness when the bell (6) rests thereon. The bell (6) is supported by means comprising an extendable cylinder (13) capable of lowering and raising the bell (6), such that it alternates between a lower position in which it rests on the platform (3) and an upper position in which it is separated from the platform (3). A connecting tube with a vacuum source, not shown in the figure, allows the vacuum to be created inside the bell (6). In the image of Fig. 4A, the bell (6) is in the upper position, separated from the platform (3).At this time, both the interior space of the can (100) and the space around the can (100) and the lid (200) are at ambient pressure.

[0050] Fig. 4B shows how, as the platform (3) passes through the closing station (EC) during its continuous movement through the machine (1), the cylinder (13) extends to lower the bell (6) until it rests on the platform (7). The lower edge (6¡) is pressed against the seal of the platform (3), thus constituting a hermetic seal separating the interior space of the bell (6) from the exterior space.

[0051] Fig. 4C shows a moment when the platform (3) has reached the vacuum station (EV) during its continuous travel through the machine (1). During this stage, the cylinder (7) raises the platform (3) a small distance. This compresses the lid (200) against the canister (100), since the lid (200) is in contact with an area of ​​the top of the bell (6). At this station, the vacuum means (not shown) extracts the air from the bell (6). Since the lid (200) is not fixed to the canister (100), it also extracts the air from the interior of the canister (100). Therefore, at the end of this stage both the interior space of the canister (100) and the space outside the canister (100) but inside the bell are subjected to vacuum.

[0052] Fig. 4D shows the last step, which occurs with the platform (3) already in the opening station (EA) at the end of the continuous circular path of the platform (3). Here the bell (6) rises again, separating itself from the platform (3). The platform (3) also descends again to its lower position. The immediate entry of air into the space previously closed by the bell (6) causes, due to the pressure difference, the lid (200) to be firmly fixed to the can (100).

Claims

CLAIMS 1. Vacuum can sealing machine (1), which is configured to continuously carry out the vacuum sealing of cans (100) by means of corresponding lids (200), characterized in that it comprises: - a housing (2) provided with a can inlet (21) and a lid inlet (22); - a plurality of individual platforms (3) moving continuously along a closed path through a closing station (EC), a vacuum station (EV) and an opening station (EA), - a first conveyor (4) arranged at the entrance of boats (21) to receive the boats (100), transport them and deposit each of said boats (100) on a corresponding platform (3); - a second conveyor (5) arranged at the lid inlet (22) to receive the lids (200), transport them, and place each lid (200) on a corresponding can (100); - the closing station (EC), where a plurality of bells (6) descend towards the mentioned platforms (3), such that a lower edge (6¡) of each bell (6) rests hermetically on an upper surface of the corresponding platform (3), leaving inside each bell (6) a can (100) with its lid (200) resting on it; - the vacuum station (EV) where, once the bells (6) are supported on the corresponding platform (3), with the platform (3) slightly raised with the help of a lower cylinder (7), the lid (200) being compressed against the can (100) by resting the base of the can (100) on the platform (3) and the lid (200) on an upper part of the interior of the bell (6), a vacuum being applied to the interior of each bell (6) by means of a vacuum system connected to an upper end of each of the bells (6), the vacuum reaching the interior of each can (100); - the opening station (EA), where each bell (6) rises to separate from the aforementioned platform (3) and break the vacuum inside the bell (6), such that the vacuum previously created inside the can (100) causes the corresponding lid (200) to be fixed by pressure to said can (100); and - a closed can exit (23) to which the closed cans are transported by a third conveyor (8) past the opening station (EA).

2. Machine (1) according to claim 1, wherein each assembly formed by platform (3), pusher (7) and bell (6) is mounted to movement means that cause its continuous movement along said closed path, such that it passes successively next to some ends of the first and second conveyors (4, 5) to receive the cans (100) and the lids (200), through the closing station (EC) where the bells (6) descend, through the vacuum station (EV) where vacuum is applied, through the opening station (EA) where the bells (6) ascend, and next to one end of the third conveyor (8) to remove the closed cans, each assembly being again empty to receive another can (100) and another lid (200) when passing again next to the ends of the first and second conveyors (4, 5).

3. Machine (1) according to any of the preceding claims, further comprising a star (10) configured to pass the cans (100) from the end of the first conveyor (4) to the corresponding platforms (7).

4. Machine (1) according to any of the preceding claims, wherein each platform (7) comprises an elastomeric seal made of an elastomeric material to ensure tightness when it supports the lower edge (6¡) of the corresponding bell (6).

5. Machine (1) according to any of the preceding claims, further comprising sensors configured to ensure that each can (100) has been correctly closed.

6. Machine (1) according to claim 5, further comprising a rejection conveyor (14) to which cans that have not been properly closed are expelled.

7. Method for vacuum sealing cans carried out by the machine (1) according to any of the preceding claims, characterized by which includes: - transporting a boat (100) from a boat entrance (21) to place it on a platform (3); - transporting a lid (200) from a lid inlet (22) to place it on the can (100); - lowering a bell (6) towards the platform (3) such that a lower edge (6¡) of the bell (6) rests hermetically on an upper surface of the platform (3), the can (100) with its lid (200) placed thereon remaining inside the bell (6); - applying vacuum to the interior of the bell (6) by means of a vacuum system connected to an upper end of the bell (6), the vacuum reaching the interior of each can (100); - slightly raise the platform (3) with the help of a lower cylinder (7), leaving the lid (200) compressed against the can (100) by resting the base of the can (100) on the platform (3) and the lid (200) on an upper part of the interior of the bell (6), leaving an interior space of each can (100) separated from a space outside the can (100); - raise the bell (6) to separate it from the aforementioned platform (3), so that the vacuum created inside the can (100) causes the corresponding lid (200) to be fixed by pressure to said can (100); and - transport the closed boat to a boat exit (23).

Images