Patent Application
20170029146
The present invention relates to an apparatus and to a process for packaging of a product. In accordance with certain aspects, the invention relates to an apparatus and process for skin packaging of a product.
Plastic containers are used for the packaging of items, such as food or other products. A plastic film or a lid may be bonded to the plastic container thereby obtaining a closed package containing the product.
In accordance with a first technique a lid may be applied to a container by heat bonding of the lid to the top rim of the container. For example, EP0469296 discloses an induction sealing apparatus configured for sealing a plastic lid to a plastic container. The apparatus includes a nest having a recess for holding a container to be sealed, and a movable sealing head configured for holding a precut and flat lid and for positioning the lid relative to an opening in the container. An induction coil mounted in the sealing head induces a heating electrical current in the lid to seal the lid to the container. This solution is not adequate to packaging of products protruding above the top rim of the container because the lid is flat and the apparatus is configured to handle flat lids only.
A second technique, known as vacuum skin packaging is employed for packaging food products. Vacuum skin packaging is described for instance in FR 1 258 357, FR 1 286 018, AU 3 491 504, U.S. Pat. No. RE 30 009, U.S. Pat. No. 3,574,642, U.S. Pat. No. 3,681,092, U.S. Pat. No. 3,713,849, U.S. Pat. No. 4,055,672, U.S. Pat. No. 5,346,735 and WO2011/012652.
Vacuum skin packaging is basically a thermoforming process. In particular, the product is placed on a support (such as a tray, a bowl or a cup) and then the support with the product placed thereon is put in a vacuum chamber, where a film of thermoplastic material, held by vacuum in a position above the product placed on the support, is heated to soften it. The space between the support and the film is then evacuated and finally vacuum above the film is released to cause the film to drape down all around the product and seal to the surface of the support not covered by the product, thus forming a tight skin around the product and on the support.
In the case of a product protruding above the edge of the tray, the film holder may be concave and e.g. shaped as a dome in order to host the protruding portion of the product during application of the plastic skin.
For instance, in order to package a bulky product having a portion protruding from the tray top rim, US 2005/0257501 shows a device consisting of an upper tool and a lower tool. The upper tool comprises an internal space in which a forming device with a concave opening facing the lower tool is fixedly mounted. A sealing tool is provided which is movable from the retracted position into the sealing position and a cutting blade which is surrounding the sealing device and which is also pneumatically movable from the retracted position to the cutting position as shown in and back is provided. After film and tray positioning, an evacuating is performed above the upper film having the consequence of the upper film being sucked to the inner wall of the forming device and thus being stretched. After the upper film is sucked to the internal surface of the forming device, the sealing tool is moved into the sealing position and thereby the edge of the tray and the upper film are sealed hermetically. Subsequently, the cutting blade is operated and thereby the completed package is separated from the upper film layer. Although this apparatus may be used for packaging products protruding above the top rim of the tray, it should be noted that the described apparatus is suitable for products of a same standardized size.
In US3694991 a vacuum skin packaging apparatus capable of packaging products above a flat board is described; according to this document the product on the flat board is placed in a vacuum chamber and a sheet of thermoplastic film is placed above the product. A portion of the film is drawn against the concave interior surface of the upper portion of a vacuum chamber; the film is then heated by surface contact; and then, after evacuation of the chamber, air pressure is used to blow the film down over the product and against the flat board. The height of the chamber may be adjusted before execution of the above cycle by locating an adapter between the upper and the lower portions of the vacuum chamber. Although the described apparatus allows packaging of different products, adjusting the height of the vacuum chamber is not practical and, additionally, the specific design of this apparatus is not adapted to packaging of products in trays, let alone of bulky products.
Thus it is an object of the invention conceiving a packaging process and a packaging apparatus which can overcome the limitations of the known solutions described above.
In particular, it is a main object of the invention, to offer a packaging process and a packaging apparatus which may effectively adapt to packaging of products protruding above the support or tray and still be able to effectively package products not emerging above the respective support or tray.
A further object of the invention is a packaging process and a packaging apparatus configured to packaging products of different sizes and degrees of protrusion above the respective support or tray.
In particular, it is an object of the invention to provide a packaging process and a packaging apparatus adapted to packaging of products having a high degree of protrusion above the support or tray.
An ancillary object of the invention is a packaging process and a packaging apparatus capable of adapting to product protrusions of various geometries and in particular to products having protrusions located in the vicinity of tray or support top rim.
Another auxiliary object of the invention is to offer a packaging process and a packaging apparatus having the ability to reduce imperfections, such are plies or wrinkles, on the film applied to the product and thus improve the appearance of the final packaged product.
Moreover, it is another object of the invention to offer a packaging process and a packaging apparatus adapted for skin packaging of products.
Another object is that of offering a process and an apparatus capable of increasing productivity, without negatively impacting on the quality and reliability of the packaging.
One or more of the objects specified above are substantially achieved by a process and by an apparatus according to any one of the appended claims
Aspects of the invention are here below disclosed.
A 1st aspect concerns an apparatus (1) for packaging a product (P) arranged on a support (4), said apparatus (1) comprising:
a film supplying assembly (5) configured for supplying at least one film (10a);
a packaging assembly (8) configured for tightly closing said one or more supports (4) with said film (10a), the packaging assembly (8) including:
It should be noted that the active surface (37) of the head (36) may for instance be flat or dome shaped (i.e. concave with concavity facing the lower tool when the upper and lower tools are in sad second operating condition). In both cases the final shape and the volume of the cavity (40) is defined by the relative position taken by the peripheral body and the head.
In a 2nd aspect according to the 1st aspect, the packaging apparatus further comprises a control unit (100) connected to the packaging assembly (8) and configured for executing a film deformation procedure comprising the steps of:
In a 3rd aspect according to any one of the preceding aspects, the lower tool is configured for receiving at least one of said supports (4) having a base wall (4a) and a side wall (4b), with a product (P) hosted therein and protruding above a top rim of said side wall (4b).
In a 4th aspect according to any one of the preceding two aspects said commanding the relative motion comprises commanding relative motion of the peripheral body (90) with respect to the head (36) from an end stroke position, where a terminal surface (95) of the peripheral body is aligned or substantially aligned with the active surface (37) of the head (36), to an operating position, where the terminal surface (95) of the peripheral body (90) is displaced from the active surface (37) by a distance (Hc) (which in the case of a flat active surface represents the height of said cavity (40)), the cavity having a volume (V) the size of which is depending upon the relative positioning of the peripheral body with respect to the holding head.
Alternatively, in case the active surface is dome shaped, said commanding the relative motion comprises commanding relative motion of the peripheral body (90) with respect to the head (36) from an end stroke position, where a terminal surface (95) of the peripheral body is aligned or substantially aligned with the peripheral edge of the active surface (37) of the head (36), to an operating position, where the terminal surface (95) of the peripheral body (90) is displaced from the peripheral edge of the active surface (37) by a distance (Hc), the cavity having a volume (V) the size of which is depending upon the relative positioning of the peripheral body with respect to the holding head.
In both alternatives the distance Hc, i.e. the relative stroke between peripheral body (90) and head (36), greater than 5 mm, optionally greater than 10 mm, more optionally greater than 20 mm, even more optionally greater than 30 mm. The maximum value of Hc, i.e. the maximum value of said relative stroke, may reach 100 mm or even up to 200 mm.
In a 5th aspect according to any one of the preceding three aspects wherein the control unit (100) is configured for first commanding the relative motion and then activating the holding means (38) such that said cavity (40) is formed before causing said film portion (10b; 18a) to move from a substantially flat configuration to a substantially tri-dimensional configuration inside said cavity.
In a 6th aspect according to any one of aspects from the 2nd to the 4th, wherein the control unit (100) is configured for commanding the relative motion after or contemporaneously with activating the holding means (38) such that said cavity (40) is formed together with causing said film portion (10b; 18a) to move from a substantially flat configuration to a substantially tri-dimensional configuration inside said cavity.
In a 7th aspect according to any one of the preceding aspects wherein said peripheral body (90) is slidingly and tightly guided along a side surface (37a) of said head.
In a 8th aspect according to any one of the preceding aspects wherein the apparatus comprises a dedicated actuator (94) carried by the upper tool (21; 21′, 21″) and mounted to act on one or both the peripheral body and the head to determine said relative motion, said control unit (100) being configured for controlling the dedicated actuator (94) to bring and stably keep the peripheral body (90) and the head (36) in one of said relative positions defining said cavity.
In a 9th aspect according to any one of the preceding aspects, wherein elastic means (94′) is interposed between the peripheral body and the upper tool, the elastic means being positioned and configured to normally bias the peripheral body at an end stroke position, where a terminal surface (95) of the peripheral body is aligned or substantially aligned with the active surface (37) of the head (36).
In a 10th aspect according to the preceding aspect a main actuator (33) is active on said upper tool (21; 21′, 21″) under the control of the control unit (100), said control unit (100) being configured for controlling the main actuator (23) to bring and stably keep the peripheral body (90) and the head (36) in one of said relative positions defining said cavity.
In an 11th aspect according to any one of the preceding aspects the control unit (100) is configured to at least control activation of the holding means (38) such as to cause pulling of said film portion (10b; 18a) inside said cavity (40) and shaping of said film portion to the shape of the cavity.
In a 12th aspect according to any one of the preceding aspects the head (36) comprises a flat active surface (37) and a prismatic or cylindrical side surface (37a) extending perpendicular to the active surface, and wherein the peripheral body (90) comprises an inner wall (92) which surface is shaped as the head side surface (37a) thereby defining a cavity of cylindrical or prismatic shape.
In a 13th aspect according to any one of the preceding aspects the apparatus is further comprising at least one sensor (50) communicating with said control unit (100) and configured to detect a value taken by at least one parameter in the group of:
In a 14th aspect according to the preceding aspect the control unit is configured to:
In a 15th aspect according to any one of the preceding aspects wherein said holding means (38) comprises:
In a 16th aspect according to any one of the preceding aspects wherein the packaging assembly (8) further comprises:
In a 17th aspect according to any one of the preceding aspects wherein the packaging assembly (8) further comprises:
In a 18th aspect according to any one of the preceding aspects comprising the heating means is configured to heat at least the active surface (37) of the head (36) and controlled by the control unit (100).
In a 19th aspect according to the preceding aspect, the control unit (100) is configured for controlling the heating means such that the active surface of the head (36) is brought at least to an operating temperature comprised between 150° C. and 260° C.
In a 20th aspect according to the preceding aspect the control unit (100) is configured for controlling the heating means such that the active surface of the head (36) is brought at least to an operating temperature comprised between 180-240° C.
In a 21st aspect according to the preceding aspect the control unit (100) is configured for controlling the heating means such that the active surface of the head (36) is brought at least to an operating temperature comprised between 200-220° C.
In a 22nd aspect according to any one of the preceding four aspects, the heating means is configured to also heat the terminal surface (95) to allow heat bonding of the film portion (10b; 18a) to the support or tray (4).
In a 23rd aspect according to the preceding aspect the control unit (100) is configured for controlling the heating means such that the terminal surface (95) of the peripheral body is kept at a temperature or temperatures equal or below the operating temperature of said active surface (37).
In a 24th aspect according to any one of the preceding aspects from the 18th to the 23rd the heating means (60) comprises a heating structure (61) conductively connected to the head (36) and/or heaters integrated into the head body.
In a 25th aspect according to any one of the preceding aspects from the 19th to the 24th the control unit is configured to bring the active surface (37) at said operating temperature before causing said film portion to move to said substantially tri-dimensional configuration inside said cavity.
In a 26th aspect according to any one of the preceding aspects from the 19th to the 25th the control unit is configured to bring the active surface (37) at said operating temperature before initiating said film deformation procedure.
In a 27th aspect according to any one of the preceding aspects from the 19th to the 26th, the control unit is configured to keep the active surface (37) at said operating temperature across a plurality of packaging cycles.
In a 28th aspect according to any one of the preceding aspects the apparatus further comprises:
a film supplying assembly (5) configured for supplying a continuous film,
a film cutting assembly (6) active on the continuous film (10a) and configured for cutting film sheets (18) of prefixed length from said continuous film (10a), wherein the film cutting assembly (6) is located outside said packaging chamber (24);
a backing structure (16) having a flat holding surface (17) adapted for receiving the at least one or more of said film sheets (18) cut by the cutting assembly (6), and
a displacement mechanism (25) active on the packaging assembly (8) and configured for displacing the upper tool (21; 21′, 21″) between a first position, where the upper tool (21; 21′, 21″) is positioned in correspondence of the backing structure (16) and configured to pick up from the backing structure (16) the one or more cut film sheets (18), and at least a second position, where the upper tool (21; 21′, 21″) is aligned to the lower tool (22) and configured to position at least one film sheet (18) above said support (4), and
a vacuum arrangement (27) connected to the packaging chamber (34),
wherein the control unit (100) is further configured for:
In a 29th aspect according to the preceding aspect the control unit is further configured to control the heating means to warm the cut film sheet or at least the peripheral edge of the cut film sheet and heat bond this latter to the support, optionally to the support top rim.
In a 30th aspect according to any one of the preceding aspects from the 1st to the 27th, the apparatus is further comprising:
a film supplying assembly (5) configured for supplying a continuous film (10a),
a film cutting assembly (6) located inside said packaging chamber (24) and presenting a blade (14) positioned radially outside said peripheral body (90);
a stopper frame (110) interposed between the upper and the lower tools (20, 21) and configured to move relative to the upper tool from a release condition, where the continuous film (10a) is allowed to move, and a stop condition, where the stopper frame blocks the continuous film against an abutting surface of the upper tool and stops said film portion (10b) above at least one respective support (4); and
a vacuum arrangement (27) connected to the packaging chamber (24);
wherein the control unit (100) is further configured for:
In a 31st aspect according to the preceding aspect the control unit is further configured to control the heating means to warm the film potion or at least the film section (10d) and heat bond this latter to the support, optionally to the support top rim.
In a 32nd aspect according to any one of the preceding aspects from the 1st to the 27th, the apparatus is further comprising:
a film supplying assembly (5) configured for supplying a continuous film (10a);
a tray supply assembly (140) configured for supplying a continuous web (141) including a plurality of thermoformed supports (4) in the form of interconnected trays; and
a vacuum arrangement (27) connected to the packaging chamber (24);
wherein the control unit (100) is further configured for:
In a 33rd aspect according to the preceding aspect said portion of the continuous web (141) moved into the packaging assembly (8) comprises a plurality of supports (4) and wherein the portion of the continuous film (10a) moved into the packaging assembly (8) is configured at an acute angle (a) with respect to the horizontal, further wherein the step of bringing the upper tool (21) in contact with the continuous film (10a) comprises bringing the upper tool first in contact with a leading section (10c) of the continuous film closer to the film supply assembly and then said portion (10b).
In a 34th aspect according to the preceding aspect the control unit is further configured to control the heating means to warm the film potion or at least the film section (10d) and heat bond this latter to the support, optionally to the support top rim.
In a 35th aspect according to any one of the preceding aspects from the 1st to the 27th, the apparatus is further comprising:
a film supplying assembly (5) configured for supplying a continuous film,
a film cutting assembly (6) active on the continuous film (10a) and configured for cutting film sheets (18) of prefixed length from said continuous film (10a), wherein the film cutting assembly (6) is located outside said packaging chamber (24); and
a backing structure (16) having a flat holding surface (17) adapted for receiving the at least one or more film sheets (18) cut by the cutting assembly (6);
a transfer mechanism (19) active on the backing structure (16) and configured for relative movement of the backing structure (16) with respect to the packaging assembly (8) between a first position, where the baking structure (16) is positioned at the cutting assembly (6) and at least a second position, where the backing structure (16) is positioned inside said packaging chamber (24) and configured to place the at least one film sheet (18) in front of said active surface of the head;
a vacuum arrangement (27) connected to the packaging chamber (24);
wherein the control unit (100) is further configured for:
In a 36th aspect according to the preceding aspect the control unit is further configured to control the heating means to warm the cut film sheet or at least the peripheral edge of the cut film sheet and heat bond this latter to the support, optionally to the support top rim.
In a 37th aspect according to any one of aspects from the 28th to the 36th the vacuum arrangement (27) connected to the packaging chamber (24) and configured for removing gas from said packaging chamber (24) comprises at least one vacuum pump (28) and at least one evacuation pipe (29) connecting the inside of said packaging chamber (24) to the vacuum pump (28), said control unit (100) being further configured to control the vacuum arrangement (27) to withdraw gas from said packaging chamber (24) at least when the packaging assembly (8) is in said second operating condition with said packaging chamber (24) hermetically closed.
In a 38th aspect according to any one of the preceding aspects the lower tool (22) is provided with multiple seats (23), each seat configured for hosting a corresponding support (4) and wherein the upper tool (21).
A 39th aspect concerns a process of packaging a product (P) arranged on a support (4) comprising the following steps:
In a 40th aspect according to the preceding aspect the support (4) comprises at least one tray having a base wall (4a) and a side wall (4b) and a top rim (4c).
In a 41st aspect according to any one of the preceding two aspects, said process uses an apparatus (1) according to any one of the preceding aspects from the 1st to the 38th.
In a 42nd aspect according to any one of the preceding three aspects the process comprises comprising cutting of the film (10a) into film sheets (18) outside the packaging chamber (24) at a station remote from the location where the film sheets are coupled to the supports, wherein supplying the film to the packaging assembly comprises supplying cut film sheets (18), further wherein the support (4) comprises a rim (4c) radially emerging from said side wall (4b) and delimiting a mouth of the support (4), and wherein the film sheet (18) is cut to a size to tightly close the mouth of the support (4) and sealingly engage the rim (4c) top surface.
In a 43rd aspect according to any one of the preceding four aspects, the process comprises heating the active surface (37) of said head (36) to cause heating of said film portion at least before pulling the same film portion inside said cavity.
In a 44th aspect according to the preceding aspect heating the active surface comprises bringing the active surface of the head (36) at least to an operating temperature comprised between 150° C. and 260° C., more optionally between 180-240° C., even more optionally between 200-220° C.
In a 45th aspect according to the any one of the preceding aspects from the 39th to the 44th the step of relatively moving the peripheral body with respect to the head in order to define the cavity comprises displacing the peripheral body with respect to the head from an end stroke position, where a terminal surface (95) of the peripheral body is aligned or substantially aligned with the active surface (37) of the head, to an operating position, where the terminal surface of the peripheral body is displaced from the active surface by a distance which represents the height of said cavity.
In a 46th aspect according to the any one of the preceding aspects from the 39th to the 45th the step of causing said film portion to move from a substantially flat configuration to a substantially tri-dimensional configuration inside said cavity takes place after or contemporaneously with formation of said cavity.
In a 47th aspect according to the any one of the preceding aspects from the 39th to the 46th the process comprises detecting or calculating one of:
In a 48th aspect according to the any one of the preceding aspects from the 39th to the 47th after formation of said cavity (40), the same cavity is kept unchanged at least until heat sealing of the film portion to the support.
In a 49th aspect according to the any one of the preceding aspects from the 39th to the 48th said film portion (10b) during or at least at the end of said deformation contacts the inside wall of said cavity and optionally takes the same shape of the cavity (40).
In a 50th aspect according to the any one of the preceding aspects from the 39th to the 49th the step of supplying a plastic film (10a) comprises supplying a continuous plastic film (10a), further wherein the process comprises:
In a 51st aspect according to the any one of the preceding aspects from the 39th to the 49th the step of supplying a plastic film comprises supplying a continuous plastic film, further wherein the process comprises:
In a 52nd aspect according to the any one of the preceding aspects from the 39th to the 49th the step of supplying a plastic film comprises supplying a continuous plastic film (10a) between the upper and lower tools; the process including:
In a 53rd aspect according to the any one of the preceding aspects from the 39th to the 49th the step of supplying a plastic film (10a) comprises:
In a 54th aspect in accordance with any one of aspects from the 35th to the 53rd the transfer mechanism (300) configured for positioning the cut film sheets (18) inside the packaging assembly and above the respective support (4) is further configured to act on a backing structure (16) having a flat holding surface (17) adapted for receiving the at least one or more film sheets (18) cut by blade (14).
The transfer mechanism may include a transfer actuator (301), e.g. carried by frame (2), active on the backing structure (16) and configured for relatively moving the backing structure (16) with respect to the packaging assembly (8) between a first position, where the baking structure (16) is positioned by the cutting device e.g. immediately downstream the blade (14) with respect to the movement imposed to film (10a), and at least a second position, where the backing structure (16) is positioned inside packaging assembly (8).
In a 55th aspect according to the preceding aspect the transfer actuator (301) is configured to be active on the backing structure (16) and configured for pushing and pulling the backing structure along a path suitable for achieving the displacement between said first and second positions: for example, the transfer actuator may displace the backing structure along a direction parallel to an horizontal direction. The transfer actuator stroke is such that the backing structure positions at least one film sheet (18) above said support (4) inside the packaging assembly (8) just in front of a central portion of the upper tool (21). The transfer actuator 301 may comprise at least one electric, pneumatic or hydraulic actuator.
In a 56th aspect according to any one of the preceding two aspects the transfer actuator is controlled by the control unit (100), which is also configured to control a positioning system (302), e.g. comprising a vacuum system connected to one or more channels (303) present in the backing structure and leading to apertures located one holding surface (17), of the transfer mechanism for maintaining the cut film sheet or sheets in proper position above the backing structure (16) at least until the upper tool holding means picks the cut film sheet from the backing structure (16).
In a 57th aspect according to the preceding aspect the control unit is configured to coordinate the actuation of transfer actuator (301), the actuation of the positioning system (302), the actuation of the holding means (38) and, optionally, that of the cutting assembly (6) such that:
It is to be noted that the transfer mechanism (300) may also include further actuators and, in a variant, cause the backing structure to move back and forth between the first and the second position following a nonlinear trajectory.
In a 58th aspect according to anyone of the preceding aspects the head and the peripheral body are mounted for relative motion the one with respect to the other among a plurality of relative positions and being configured for defining a cavity (40) delimited by said active surface (37) and by an inner wall (92) of said peripheral body: the maximum stroke of said relative motion being greater than 5 mm.
In a 59th aspect according to anyone of the preceding aspects the head and the peripheral body are mounted for relative motion the one with respect to the other among a plurality of relative positions and being configured for defining a cavity (40) delimited by said active surface (37) and by an inner wall (92) of said peripheral body: the maximum stroke of said relative motion being greater than 10 mm.
In a 60th aspect according to anyone of the preceding aspects the head and the peripheral body are mounted for relative motion the one with respect to the other among a plurality of relative positions and being configured for defining a cavity (40) delimited by said active surface (37) and by an inner wall (92) of said peripheral body: the maximum stroke of said relative motion being greater than 20 mm.
In a 61st aspect according to anyone of the preceding aspects the head and the peripheral body are mounted for relative motion the one with respect to the other among a plurality of relative positions and being configured for defining a cavity (40) delimited by said active surface (37) and by an inner wall (92) of said peripheral body: the maximum stroke of said relative motion being greater than 30 mm and may reach 100 mm or even up to 200 mm.
Aspects of the present invention are disclosed in the following detailed description, given by way of example and not of limitation, to be read with reference to the accompanying drawings, wherein:
It should be noted that in the present detailed description corresponding parts shown in the various figures are indicated with the same reference numeral through the figures. Note that the figures are not in scale and thus the parts and components shown therein are schematic representations.
In the following description and claims the apparatus and process refer to packaging of a product inside a support: the product may be a food product or not.
As used herein support 4 means a container of the type having a base wall 4a, a side wall 4b and optionally a top rim 4c radially emerging from the side wall 4b; alternatively the support or tray may be flat and may be made either in plastic material or in cardboard.
Note that for the purpose of the present description tray and support have the same meaning and are interchangeably used. The tray or supports 4 may have a rectangular shape or any other suitable shape, such as round, square, elliptical and other. Trays or supports with a side wall may be manufactured by thermoforming or injection molding or in—case of flat supports—they may be extruded, co-extruded, laminated and then the cut to size.
The trays or supports 4 described and claimed herein may be made of a single layer or of a multi-layer polymeric material.
In case of a single layer material suitable polymers are for instance polystyrene, polypropylene, polyesters, high density polyethylene, poly(lactic acid), PVC and the like, either foamed or solid.
Preferably the tray 4 is provided with gas barrier properties. As used herein such term refers to a film or sheet of material which has an oxygen transmission rate of less than 200 cm3/m2-day-bar, less than 150 cm3/m2-day-bar, less than 100 cm3/m2-day-bar as measured according to ASTM D-3985 at 23° C. and 0% relative humidity. Suitable materials for gas barrier monolayer thermoplastic trays 4 are for instance polyesters, polyamides and the like.
In case the tray 4 is made of a multi-layer material, suitable polymers are for instance ethylene homo- and co-polymers, propylene homo- and co-polymers, polyamides, polystyrene, polyesters, poly(lactic acid), PVC and the like. Part of the multi-layer material can be solid and part can be foamed.
For example, the tray 4 may comprises at least one layer of a foamed polymeric material chosen from the group consisting of polystyrene, polypropylene, polyesters and the like.
The multi-layer material may be produced either by co-extrusion of all the layers using co-extrusion techniques or by glue- or heat-lamination of, for instance, a rigid foamed or solid substrate with a thin film, usually called “liner”.
The thin film may be laminated either on the side of the tray 4 in contact with the product P or on the side facing away from the product P or on both sides. In the latter case the films laminated on the two sides of the tray 4 may be the same or different. A layer of an oxygen barrier material, for instance (ethylene-co-vinyl alcohol) copolymer, is optionally present to increase the shelf-life of the packaged product P.
Gas barrier polymers that may be employed for the gas barrier layer are PVDC, EVOH, polyamides, polyesters and blends thereof. The thickness of the gas barrier layer will be set in order to provide the tray with an oxygen transmission rate suitable for the specific packaged product.
The tray may also comprise a heat sealable layer. Generally, the heat-sealable layer will be selected among the polyolefins, such as ethylene homo- or co-polymers, propylene homo- or co-polymers, ethylene/vinyl acetate copolymers, ionomers, and the homo- and co-polyesters, e.g. PETG, a glycol-modified polyethylene terephthalate. Additional layers, such as adhesive layers, to better adhere the gas-barrier layer to the adjacent layers, may be present in the gas barrier material for the tray and are preferably present depending in particular on the specific resins used for the gas barrier layer.
In case of a multilayer material used to form the tray 4, part of this structure may be foamed and part may be un-foamed. For instance, the tray 4 may comprise (from the outermost layer to the innermost food-contact layer) one or more structural layers, typically of a material such as foam polystyrene, foam polyester or foam polypropylene, or a cast sheet of e.g. polypropylene, polystyrene, poly(vinyl chloride), polyester or cardboard; a gas barrier layer and a heat-sealable layer.
The tray 4 may be obtained from a sheet of foamed polymeric material having a film comprising at least one oxygen barrier layer and at least one surface sealing layer laminated onto the side facing the packaged product, so that the surface sealing layer of the film is the food contact layer the tray. A second film, either barrier or non-barrier, may be laminated on the outer surface of the tray.
Specific tray 4 formulations are used for food products which require heating in conventional or microwave oven before consumption. The surface of the container in contact with the product, i.e. the surface involved in the formation of the seal with the lidding film, comprises a polyester resin. For instance the container can be made of a cardboard coated with a polyester or it can be integrally made of a polyester resin. Examples of suitable containers for the package of the invention are CPET, APET or APET/CPET containers. Such container can be either foamed or not-foamed.
Trays 4 containing foamed parts, have a total thickness lower than 8 mm, and for instance may be comprised between 0.5 mm and 7.0 mm and more frequently between 1.0 mm and 6.0 mm.
In case of rigid tray not containing foamed parts, the total thickness of the single-layer or multi-layer thermoplastic material is preferably lower than 2 mm, and for instance may be comprised between 0.1 mm and 1.2 mm and more frequently between 0.2 mm and 1.0 mm.
The film or film material 10a described and claimed herein may be applied to the tray or support 4 to form a lid onto the tray (e.g. for MAP—modified atmosphere packaging) or a skin associated to the tray and matching the contour of the product.
The film for skin applications may be made of a flexible multi-layer material comprising at least a first outer heat-sealable layer, an optional gas barrier layer and a second outer heat-resistant layer. The outer heat-sealable layer may comprise a polymer capable of welding to the inner surface of the supports carrying the products to be packaged, such as for instance ethylene homo- or co-polymers, like LDPE, ethylene/alpha-olefin copolymers, ethylene/acrylic acid copolymers, ethylene/methacrylic acid copolymers, and ethylene/vinyl acetate copolymers, ionomers, co-polyesters, e.g. PETG. The optional gas barrier layer preferably comprises oxygen impermeable resins like PVDC, EVOH, polyamides and blends of EVOH and polyamides. The outer heat-resistant layer may be made of ethylene homo- or copolymers, ethylene/cyclic-olefin copolymers, such as ethylene/norbornene copolymers, propylene homo- or co-polymers, ionomers, (co)polyesters, (co)polyamides. The film may also comprise other layers such as adhesive layers or bulk layers to increase thickness of the film and improve its abuse and deep drawn properties. Particularly used bulk layers are ionomers, ethylene/vinyl acetate copolymers, polyamides and polyesters. In all the film layers, the polymer components may contain appropriate amounts of additives normally included in such compositions. Some of these additives are preferably included in the outer layers or in one of the outer layers, while some others are preferably added to inner layers. These additives include slip and anti-block agents such as talc, waxes, silica, and the like, antioxidants, stabilizers, plasticizers, fillers, pigments and dyes, cross-linking inhibitors, cross-linking enhancers, UV absorbers, odour absorbers, oxygen scavengers, bactericides, antistatic agents and the like additives known to those skilled in the art of packaging films.
One or more layers of the film can be cross-linked to improve the strength of the film and/or its heat resistance. Cross-linking may be achieved by using chemical additives or by subjecting the film layers to an energetic radiation treatment. The films for skin packaging are typically manufactured in order to show low shrink when heated during the packaging cycle. Those films usually shrink less than 15% at 160° C., more frequently lower than 10%, even more frequently lower than 8% in both the longitudinal and transversal direction (ASTM D2732). The films usually have a thickness comprised between 20 microns and 200 microns, more frequently between 40 and 180 microns and even more frequently between 50 microns and 150 microns.
The skin packages are usually “easy-to-open”, i.e. they are easily openable by manually pulling apart the two webs, normally starting from a point like a corner of the package where the upper web has purposely not been sealed to the support. To achieve this feature, either the film or the tray can be provided with a suitable composition, allowing easy opening of the package, as known in the art. Typically, the sealant composition and/or the composition of the adjacent layer of the tray and/or the film are adjusted in order to achieve the easy opening feature.
Various mechanisms can occur while opening an easy-to-open package.
In the first one (“peelable easy opening”) the package is opened by separating the film and the tray at the seal interface.
In the second mechanism (“adhesive failure”) the opening of the package is achieved through an initial breakage through the thickness of one of the sealing layers followed by delamination of this layer from the underlying support or film.
The third system is based on the “cohesive failure” mechanism: the easy opening feature is achieved by internal rupture of a seal layer that, during opening of the package, breaks along a plane parallel to the layer itself.
Specific blends are known in the art to obtain such opening mechanisms, ensure the peeling of the film from the tray surface, such as those described in EP1084186.
On the other hand, in case the film 10a is used for creating a lid on the tray or support 4, the film material may be obtained by co-extrusion or lamination processes. Lid films may have a symmetrical or asymmetrical structure and can be monolayer or multilayer.
The multilayer films have at least 2, more frequently at least 5, even more frequently at least 7 layers. The total thickness of the film may vary frequently from 3 to 100 micron, in particular from 5 to 50 micron, even more frequently from 10 to 30 micron.
The films may be optionally cross-linked. Cross-linking may be carried out by irradiation with high energy electrons at a suitable dosage level as known in the art. The lid films described above may be heat shrinkable or heat-set. The heat shrinkable films typically show free shrink value at 120° C. measured according to ASTM D2732 in the range of from 2 to 80%, more frequently from 5 to 60%, even more frequently from 10 to 40% in both the longitudinal and transverse direction. The heat-set films usually have free shrink values lower than 10% at 120° C., preferably lower than 5% in both the longitudinal and transversal direction (ASTM D 2732). Lid films usually comprise at least a heat sealable layer and an outer skin layer, which is generally made up of heat resistant polymers or polyolefin. The sealing layer typically comprises a heat-sealable polyolefin which in turn comprises a single polyolefin or a blend of two or more polyolefins such as polyethylene or polypropylene or a blend thereof. The sealing layer can be further provided with antifog properties by incorporating one or more antifog additives into its composition or by coating or spraying one or more antifog additives onto the surface of the sealing layer by technical means well known in the art. The sealing layer may further comprise one or more plasticisers. The skin layer may comprises polyesters, polyamides or polyolefin. In some structures, a blend of polyamide and polyester can advantageously be used for the skin layer. In some cases, the lid films comprise a barrier layer. Barrier films typically have an OTR (evaluated at 23° C. and 0% R.H. according to ASTM D-3985) below 100 cm3/(m2·day·atm) and more frequently below 80 cm3/(m2·day·atm). The barrier layer is usually made of a thermoplastic resin selected among a saponified or hydrolyzed product of ethylene-vinyl acetate copolymer (EVOH), an amorphous polyamide and a vinyl-vinylidene chloride and their admixtures. Some materials comprise an EVOH barrier layer, sandwiched between two polyamide layers. The skin layer typically comprises polyesters, polyamides or polyolefin.
In some packaging applications, the lid films do not comprise any barrier layer. Such films usually comprise one or more polyolefin are herein defined.
Non-barrier films typically have an OTR (evaluated at 23° C. and 0% R.H. according to ASTM D-3985) from 100 cm3/(m2·day·atm) up to 10000 cm3/(m2·day·atm), more typically up to 6000 cm3/(m2·day·atm).
Peculiar compositions polyester-based are those used for tray lidding of ready-meals packages. For these films, the polyester resins can make up at least 50%, 60%, 70%, 80%, 90% by weight of the film. These films are typically used in combination with polyester-based supports.
For instance the container can be made of a cardboard coated with a polyester or it can be integrally made of a polyester resin. Examples of suitable containers for the package are CPET, APET or APET/CPET containers, either foamed or not-foamed.
Usually, biaxially oriented PET are used as the lid film due to its high thermal stability at standard food heating/cooking temperatures. Often biaxially oriented polyester films are heat-set, i.e. non-heat-shrinkable. To improve the heat-sealability of the PET lidding film to the container a heat-sealable layer of a lower melting material is usually provided on the film. The heat-sealable layer may be coextruded with the PET base layer (as disclosed in EP-A-1,529,797 and WO2007/093495) or it may be solvent- or extrusion-coated over the base film (as disclosed in U.S. Pat. No. 2,762,720 and EP-A-1,252,008).
Particularly in the case of fresh red meat packages, twin lidding film comprising an inner, oxygen-permeable, and an outer, oxygen-impermeable, lidding film are advantageously used. The combination of these two films significantly prevents the meat discoloration also when the packaged meat extends upwardly with respect to the height of the tray walls, which is the most critical situation in barrier packaging of fresh meat.
These films are described for example in EP1848635 and EP0690012, the disclosures of which are herein incorporated by reference.
The lid film can be monolayer. Typical composition of monolayer films comprise polyesters as herein defined and their blends or polyolefins as herein defined and their blends. Double or multiple layer films may however also be used.
In all the film layers herein described, the polymer components may contain appropriate amounts of additives normally included in such compositions. Some of these additives are preferably included in the outer layers or in one of the outer layers, while some others are preferably added to inner layers. These additives include slip and anti-block agents such as talc, waxes, silica, and the like, antioxidants, stabilizers, plasticizers, fillers, pigments and dyes, cross-linking inhibitors, cross-linking enhancers, UV absorbers, odor absorbers, oxygen scavengers, bactericides, antistatic agents, anti-fog agents or compositions, and the like additives known to those skilled in the art of packaging films.
The films suitable for lidding application can advantageously be perforated, in order to allow the packaged food to breath.
Those films may be perforated by using different technologies available in the art, through laser or mechanical means such as rolls provided with several needles.
The number of perforations per unit area of the film and their dimensions affect the gas permeability of the film.
Microperforated films are usually characterized by OTR value (evaluated at 23° C. and 0% R.H. according to ASTM D-3985) from 2500 cm3/(m2·day·atm) up to 1000000 cm3/(m2·day·atm).
Macroperforated films are usually characterized by OTR (evaluated at 23° C. and 0% R.H. according to ASTM D-3985) higher than 1000000 cm3/(m2·day·atm).
Furthermore, the films herein described for lidding applications can be formulated to provide strong or peelable sealing onto the support. A method of measuring the force of a peelable seal, herein referred to as “peel force” is described in ASTM F-88-00. Acceptable peel force values fare in the range from 100 g/25 mm to 850 g/25 mm, from 150 g/25 mm to 800 g/25 mm, from 200 g/25 mm to 700 g/25 mm.
The desired seal strength is achieved specifically designing the tray and the lid formulations.
In general, one or more layers of the lid film can be printed, in order to provide useful information to the consumer, a pleasing image and/or trademark or other advertising information to enhance the retail sale of the packaged product. The film may be printed by any suitable method, such as rotary screen, gravure or flexographic techniques mas known in the art.
PVDC is any vinylidene chloride copolymers wherein a major amount of the copolymer comprises vinylidene chloride and a minor amount of the copolymer comprises one or more unsaturated monomers copolymerisable therewith, typically vinyl chloride, and alkyl acrylates or methacrylates (e.g. methyl acrylate or methacrylate) and the blends thereof in different proportions. Generally a PVDC barrier layer will contain plasticisers and/or stabilizers as known in the art.
As used herein, the term EVOH includes saponified or hydrolyzed ethylene-vinyl acetate copolymers, and refers to ethylene/vinyl alcohol copolymers having an ethylene comonomer content preferably comprised from about 28 to about 48 mole %, more preferably, from about 32 to about 44 mole % ethylene, and even more preferably, and a saponification degree of at least 85%, preferably at least 90%.
The term “polyamides” as used herein is intended to refer to both homo- and co- or ter-polyamides. This term specifically includes aliphatic polyamides or co-polyamides, e.g., polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 69, polyamide 610, polyamide 612, copolyamide 6/9, copolyamide 6/10, copolyamide 6/12, copolyamide 6/66, copolyamide 6/69, aromatic and partially aromatic polyamides or co-polyamides, such as polyamide 6I, polyamide 6I/6T, polyamide MXD6, polyamide MXD6/MXDI, and blends thereof.
As used herein, the term “copolymer” refers to a polymer derived from two or more types of monomers, and includes terpolymers. Ethylene homopolymers include high density polyethylene (HDPE) and low density polyethylene (LDPE). Ethylene copolymers include ethylene/alpha-olefin copolymers and ethylene/unsaturated ester copolymers. Ethylene/alpha-olefin copolymers generally include copolymers of ethylene and one or more comonomers selected from alpha-olefins having from 3 to 20 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene and the like.
Ethylene/alpha-olefin copolymers generally have a density in the range of from about 0.86 to about 0.94 g/cm3. The term linear low density polyethylene (LLDPE) is generally understood to include that group of ethylene/alpha-olefin copolymers which fall into the density range of about 0.915 to about 0.94 g/cm3 and particularly about 0.915 to about 0.925 g/cm3. Sometimes linear polyethylene in the density range from about 0.926 to about 0.94 g/cm3 is referred to as linear medium density polyethylene (LMDPE). Lower density ethylene/alpha-olefin copolymers may be referred to as very low density polyethylene (VLDPE) and ultra-low density polyethylene (ULDPE). Ethylene/alpha-olefin copolymers may be obtained by either heterogeneous or homogeneous polymerization processes.
Another useful ethylene copolymer is an ethylene/unsaturated ester copolymer, which is the copolymer of ethylene and one or more unsaturated ester monomers. Useful unsaturated esters include vinyl esters of aliphatic carboxylic acids, where the esters have from 4 to 12 carbon atoms, such as vinyl acetate, and alkyl esters of acrylic or methacrylic acid, where the esters have from 4 to 12 carbon atoms.
Ionomers are copolymers of an ethylene and an unsaturated monocarboxylic acid having the carboxylic acid neutralized by a metal ion, such as zinc or, preferably, sodium.
Useful propylene copolymers include propylene/ethylene copolymers, which are copolymers of propylene and ethylene having a majority weight percent content of propylene, and propylene/ethylene/butene terpolymers, which are copolymers of propylene, ethylene and 1-butene.
As used herein, the term “polyolefin” refers to any polymerized olefin, which can be linear, branched, cyclic, aliphatic, aromatic, substituted, or unsubstituted. More specifically, included in the term polyolefin are homo-polymers of olefin, co-polymers of olefin, co-polymers of an olefin and an non-olefinic co-monomer co-polymerizable with the olefin, such as vinyl monomers, modified polymers thereof, and the like. Specific examples include polyethylene homo-polymer, polypropylene homo-polymer, polybutene homo-polymer, ethylene-alpha-olefin co-polymer, propylene-alpha-olefin co-polymer, butene-alpha-olefin co-polymer, ethylene-unsaturated ester co-polymer, ethylene-unsaturated acid co-polymer, (e.g. ethylene-ethyl acrylate co-polymer, ethylene-butyl acrylate co-polymer, ethylene-methyl acrylate co-polymer, ethylene-acrylic acid co-polymer, and ethylene-methacrylic acid co-polymer), ethylene-vinyl acetate copolymer, ionomer resin, polymethylpentene, etc.
The term “polyester” is used herein to refer to both homo- and co-polyesters, wherein homo-polyesters are defined as polymers obtained from the condensation of one dicarboxylic acid with one diol and co-polyesters are defined as polymers obtained from the condensation of one or more dicarboxylic acids with one or more diols. Suitable polyester resins are, for instance, polyesters of ethylene glycol and terephthalic acid, i.e. poly(ethylene terephthalate) (PET). Preference is given to polyesters which contain ethylene units and include, based on the dicarboxylate units, at least 90 mol %, more preferably at least 95 mol %, of terephthalate units. The remaining monomer units are selected from other dicarboxylic acids or diols. Suitable other aromatic dicarboxylic acids are preferably isophthalic acid, phthalic acid, 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid. Of the cycloaliphatic dicarboxylic acids, mention should be made of cyclohexanedicarboxylic acids (in particular cyclohexane-1,4-dicarboxylic acid). Of the aliphatic dicarboxylic acids, the (C3-Ci9)alkanedioic acids are particularly suitable, in particular succinic acid, sebacic acid, adipic acid, azelaic acid, suberic acid or pimelic acid. Suitable diols are, for example aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butane diol, 1,5-pentane diol, 2,2-dimethyl-1,3-propane diol, neopentyl glycol and 1,6-hexane diol, and cycloaliphatic diols such as 1,4-cyclohexanedimethanol and 1,4-cyclohexane diol, optionally heteroatom-containing diols having one or more rings.
Co-polyester resins derived from one or more dicarboxylic acid(s) or their lower alkyl (up to 14 carbon atoms) diesters with one or more glycol(s), particularly an aliphatic or cycloaliphatic glycol may also be used as the polyester resins for the base film. Suitable dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, or 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids such as succinic acid, sebacic acid, adipic acid, azelaic acid, suberic acid or pimelic acid. Suitable glycol(s) include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butane diol, 1,5-pentane diol, 2,2-dimethyl-1,3-propane diol, neopentyl glycol and 1,6-hexane diol, and cycloaliphatic diols such as 1,4-cyclohexanedimethanol and 1,4-cyclohexane diol. Examples of such copolyesters are (i) copolyesters of azelaic acid and terephthalic acid with an aliphatic glycol, preferably ethylene glycol; (ii) copolyesters of adipic acid and terephthalic acid with an aliphatic glycol, preferably ethylene glycol; and (iii) copolyesters of sebacic acid and terephthalic acid with an aliphatic glycol, preferably butylene glycol; (iv) co-polyesters of ethylene glycol, terephthalic acid and isophthalic acid. Suitable amorphous co-polyesters are those derived from an aliphatic diol and a cycloaliphatic diol with one or more, dicarboxylic acid(s), preferably an aromatic dicarboxylic acid. Typical amorphous copolyesters include co-polyesters of terephthalic acid with an aliphatic diol and a cycloaliphatic diol, especially ethylene glycol and 1,4-cyclohexanedimethanol.
The support shown in the figures of all embodiments is in the form of a tray 4 which presents a base wall 4a, a side wall 4b emerging from the base wall and delimiting a space where a product P can be housed, and a top rim 4c radially protruding from the side wall 4b. In the examples shown the top rim 4c has a horizontal flat portion defining an optimal sealing surface for tightly fixing a plastic film.
The product P to be packaged is housed inside the tray 4 and protrudes by a height Hp above the top rim 4c of the tray. The apparatuses and processes according to below description and according to any one of the appended claims are adapted for efficiently packaging supports or trays of the type described above housing a protruding product P. Note, however, that the apparatuses and processes herein disclosed and claim are also adequate for the packaging of products which are not protruding above the top rim 4c.
As it will become apparent from below description, the apparatus 1 of
The apparatus 1 comprises a frame 2, a transport assembly 3 for displacing the support or tray 4, a film supplying assembly 5, a film cutting assembly 6, and at least one packaging assembly 8. A device for transferring the cut film sheet or sheets from the cutting assembly to a position above the tray is also present; however, how the cut film sheet is transported to the packaging assembly and above the respective tray or support is not relevant: non-limiting examples of suitable transfer devices are provided herein below.
The frame 2 defines a base body of the apparatus 1 and serves to carry and support various parts of the apparatus 1 as herein described.
The transport assembly 3 comprises a displacement plane 20 (which may be a physical plane where the trays or support are lying and slide or an ideal plane along which the trays are guided e.g. by means of railways or guides). The plane 20 is defined on a top area of the frame and a conveyor 46 is arranged in correspondence of the plane 20. In the example shown, the transport assembly 3 is carried by, e.g. fixed to, the frame 2 so that the plane 20 is substantially horizontal and the conveyor 46 moves the trays or supports 4 according to the horizontal direction indicated by the arrow A1 shown in
The film supply assembly 5 may comprise a film roll 10 which supplies a continuous film 10a. The film supplying assembly 5 may further comprise an arm 11 (represented in dashed lines in
The film cutting assembly 6 may be separate from the upper tool 21 and located at the cutting station (see
The packaging assembly 8, which is only very schematically shown in
As schematically shown in
For instance, in accordance with a 1st possible alternative—the transfer device may include a transfer mechanism acting on the cut film sheet(s) may be used for transporting the cut film sheet from the cutting station where the cutting assembly cuts the film sheets 18 into the packaging assembly 8.
In accordance with a possible alternative—the transfer device may include a displacement mechanism 25 may be configured to move the upper tool 21 from the packaging assembly 8 to the position outside where the cutting assembly 6 effects the cutting of the film sheets; in this way the upper tool is allowed to pick the cut film sheet(s) 18 and return to the packaging assembly 8 in alignment with the lower tool 22, thereby bringing the cut film sheet(s) into the packaging chamber 24 and above the trays.
Note that other ways could be envisaged for transfer of a pre-cut film sheet or sheets inside the packaging assembly 8, without departing from the scope of the invention: in practice any solution adapted to pick the film sheet and transfer it into the packaging assembly may be suitable.
In accordance with the 1st alternative, a transfer mechanism 300 may be configured for positioning the cut film sheets 18 inside the packaging assembly and above the respective support 4. The transfer mechanism 300 may act on a backing structure 16 having a flat holding surface 17 adapted for receiving the at least one or more film sheets 18 cut by blade 14:
It is to be noted that the transfer mechanism 300 may also include further actuators and cause the backing structure to move back and forth between the first and the second position following a non linear trajectory.
In accordance with the 2nd alternative—which is schematically shown in
In accordance with one aspect (see
As already mentioned, the apparatus also includes the control unit 100 which is configured for commanding the dedicated actuator, or the main actuator 33 and the dedicated actuator 94, and thus cause the relative motion of the peripheral body 90 with respect to the head 36 in order to define said cavity: for instance the control unit may control the dedicated actuator, or the main actuator and the dedicated actuator, to bring and stably keep for several seconds the peripheral body and the head in one of said relative positions such that the cavity 40 is formed and kept unchanged for the time necessary to apply the film sheet 18 to the respective tray or support 4. The control unit 100 is also configured for activating the holding means 38 and is capable of coordinating the relative motion between peripheral body and head with the activation of the holding means 38 such as to cause said film portion 18a to move from a substantially flat configuration outside said cavity to a substantially tri-dimensional configuration inside said cavity 40.
In accordance with an aspect of the invention, the control unit 100 is configured for commanding—e.g. by controlling the dedicated actuator or by controlling both the dedicated actuator and the main actuator—the movement of the head 36 relative to the peripheral body 90 from an end stroke position, where a terminal surface 95 of the peripheral body 90 is aligned or substantially aligned with the active surface 37 of the head 36 (
In the example shown in
As shown in
Note that—during pulling of the film portion inside the cavity—the terminal surface 95 of the peripheral body 90 constrains a peripheral edge 18b of the film sheet 18 against an abutment surface. In examples 1-7, the displacement mechanism 25 is configured for positioning the upper tool 21 in front of baking structure 16 and urge the terminal surface 95 of the peripheral body against the holding surface 17 which acts as abutment surface constraining the peripheral edge 18b of the cut film sheet, which can thereafter be stretched and deformed with no risk of losing its proper position with respect to the upper tool.
Thus, the control unit 100 may control activation of the holding means 38 such as to cause pulling of said film portion 18a inside said cavity 40 and shaping of said film portion 18a to the shape of the cavity 40, conferring a quite pronounced deformation to the interested film portion. For example, the head 36 may comprise a flat active surface 37 and a prismatic or cylindrical side surface 37a perpendicular to the active surface 37: consequently, as the peripheral body 90 is configured to slide along the head 36, the peripheral body comprises an inner wall 92 with a surface which is shaped as the side surface 37a of the head 36, thereby defining a cavity of cylindrical or prismatic shape. Thus, the portion of film sheet undergoing deformation may be compelled to take exactly the shape of the cavity and is therefore substantially stretched and deformed particularly in the area of the film sheet close to terminal surface 95 of the peripheral body.
According to a further aspect, the apparatus 1 comprises one or more sensors 50, which may be located on the frame 2 and which communicate with the control unit 100. Sensor 50 is configured to detect a value of a parameter which may be the height of the product hosted in a support or directly the extent of protrusion Hp of a product beyond a top rim 4c of support 4 (in case of support with side wall and top rim), or the total height of the product and the support. The sensor 50 is configured to issue a signal for the control unit linked to the detected value of the mentioned parameter and the control unit is configured to receive said signal, and command the relative motion of the peripheral body 90 with respect to the head 36 by distance Hc equal to or greater than said extent of protrusion Hp, in order to configure the cavity 40 with a height at least sufficient to host the protruding portion of the product P. Hc is typically greater than 5 mm, more typically greater than 10 mm, and even greater values as peripheral body and the head are mounted to offer a stroke of the relative motion between head and peripheral body which may be bigger than 5 mm, or bigger than 10 mm or bigger than 20 mm or 30 mm or take even bigger values such as up to 100 or 200 mm to offer the ability to adapt to basically any type of protruding product.
According to another aspect, the apparatus 1 includes heating means 60 configured to heat at least the active surface 37 of the head 36. The heating means may include resistances or inductances (e.g. in the form of printed circuits) or other type of heater(s) located inside the head 36 or in proximity of the active surface 37 (such has heating irradiators) and capable of at least directly or indirectly heating the active surface. The heating means are controlled by the control unit 100 which is configured for regulating the heating means such that the active surface of the head 36 is brought at least to an operating temperature comprised between 150° C. and 260° C., optionally between 180-240° C., more optionally between 200-220° C. One or more temperature sensors or one or more thermal switches may be positioned in correspondence or in proximity of head 36 in order to provide the control unit with a feedback signal and allow control of the active surface temperature within the above ranges. In accordance with a presently preferred aspect, the control unit controls the heating means such that the active surface is kept at said operating temperature during the whole packaging cycle such that as soon as the film touches the active surface it gets immediately and uniformly warmed. In an aspect the control unit 100 is configured for controlling the heating means such that the terminal surface 95 of the peripheral body 90 is kept at a temperature which is always below the operating temperature of said active surface 37: this has the advantage of setting the surface at a temperature which is appropriate for plastic deformation of the film sheet portion 18a and at the same time setting the terminal surface at a temperature which is optimal for heat sealing the peripheral edge 18b to the tray rim 4c or to the support without compromising the integrity thereof. In a variant, as shown in
The control unit is configured to bring the active surface 37 of head 36 at said operating temperature before initiating the deformation process of the film sheet. In other words, before causing the film portion 18a to move inside the cavity 40 and take the said substantially tri-dimensional configuration, the control unit activates the heating means and brings the active surface to the operating temperature appropriate to the film structure and material under deformation. Heating of the film increases the ability of the film to receive pronounced deformation and causes at least the peripheral film portion to stick to the terminal surface 95. As the active surface is kept at a uniform and substantially constant temperature, the film is uniformly heated and brought to optimal conditions for deformation.
Once the film portion 18a has been properly deformed and brought inside the cavity 40, then displacement mechanism 25 may cause—under the control of control unit 100—movement of the upper tool 21 to the position shown in
Once the chamber 24 has been closed, a vacuum arrangement 27 may be operated by the control unit (
In a further aspect, the control unit may be configured to create a vacuum in the packaging chamber 24 (by controlling the vacuum pump 28 to withdraw gas from said packaging chamber 24) until a sufficiently low pressure has been reached (e.g. below 100 mbar or below 50 mbar or below 10 mbar). This pressure level is sufficiently low but not too low so that detachment of the film sheet from the head 36 is avoided (at least during a first phase) as the control unit also creates a pressure level in correspondence of the suction holes 39, by acting on vacuum source 41, below the pressure level reached in the packaging chamber. Once a desired state of vacuum is reached inside the chamber 24, and after the peripheral portion of the film sheet has been sealingly fixed to the support or to the tray rim 4c, the control unit 100 commands the holding means 38 to release the film portion 18a: this may be achieved by commanding selector valve 42 (or valves 42a, 42b) to switch to the vent line 43. The vacuum causes the film 18 to drape down to the tray and to form a skin around the product also attaching to the tray surface not occupied by the product. At this point the control unit may control again the displacement mechanism 25 and lift the upper tool 21 thereby allowing extraction of the packaged product.
The cycle described above may then be repeated.
The apparatus 1 may also, or may alternatively, include a controlled atmosphere arrangement 30 connected to the packaging chamber 24 and configured for injecting a gas stream into said packaging chamber; the controlled atmosphere arrangement comprises at least one injection device including an injection pump and/or one injection valve 31 connecting the inside of said chamber 24 to a source of gas (not shown) which may be located remotely from the apparatus 1; the control unit 100 may be configured to control opening and closing of the injection valve (or activation of the injection pump) to inject said stream of gas at least when the packaging assembly 8 is in said second operating condition, i.e. with said packaging chamber 24 hermetically closed.
Although the apparatus 1 may have one or both the vacuum arrangement 27 and the controlled atmosphere arrangement 30, it is to be understood that the control unit 100 of the apparatus 1 may also be configured to tightly engage the film sheets 18 to the trays without activating the vacuum arrangement or the controlled atmosphere arrangement and thus leaving the normal environment atmosphere within the tray. This may be for instance the case for non perishable products. Thus in a version, the apparatus 1 may be designed without vacuum arrangement and without modified atmosphere arrangement.
The second embodiment is similar to the first embodiment and only differences will be re-described in detail. The frame 2 structure and the way trays 4 are moved to a the seats 23 may be same as described above in connection with the first embodiment and
In the second embodiment the cutting assembly 6 is located at a cutting station, e.g. immediately downstream the film supply assembly 5, and is separate from the upper tool 21. Moreover, the apparatus includes two (or more) upper tools 21′ and 21″ which are contemporaneously controlled such that once one of the two upper tools is applying the film sheet to the respective tray, the other of the two upper tools is brought at the cutting assembly to pick the cut film sheet up.
The displacement mechanism 25, e.g. carried by frame 2, is configured for alternately displacing the two upper tools 21′ and 21″ between a respective first position, where the upper tools are positioned in correspondence of the backing structure 16 and configured to pick up from the backing structure 16 holding surface 17 the one or more cut film sheets 18 (as e.g. upper tool 21′ in
Thus, for the upper tool facing the backing structure, the respective main actuator 33 causes an horizontal movement of the upper tool, while for the upper tool facing the lower tool the respective main actuator 33 causes a vertical up and down movement. The combined movement of the rotating actuator 26 and of the main actuators 33 allows the displacement mechanism 25 to configure each one of the upper tools alternatively in a position, where the upper tool may pick a vertically extending cut film sheet 18, and in a position, where the upper tool may cooperate with the lower tool 22 to define the packaging assembly 8. When one of the upper tools 21′ or 21″ is in the position where it is cooperating—at the packaging assembly 8—with the lower tool, the upper and lower tools allow coupling of the cut film sheet 18 to the support or tray 4 as it is further explained herein below.
Each upper tool 21′ and 21″ is designed and configured like the upper tool 21 of the first embodiment and comprises the same components (which are not described again in detail):
As already mentioned, one of the two upper tools, namely upper tool 21′, is brought in a position facing the backing structure 16 (
Under the action of its main actuator 33, the upper tool 21′ is moved towards the cut film sheet positioned on the backing structure holding surface 17 so that the active surface 37 and the terminal surface 95 are closely approached or come into contact with film sheet 18 (
Alternatively, the control unit 100 may be configured for first commanding the relative motion of the head 36 with respect to the peripheral body 90 and then—once the cavity 40 is partially or totally formed—activating the holding means 38, such that first said cavity is formed and then the film portion is forced to move from a substantially flat configuration to a substantially tri-dimensional configuration inside said cavity.
During pulling of the film portion 18a inside the cavity—the terminal surface 95 of the peripheral body 90 constrains a peripheral edge 18b of the film sheet 18 against an abutment surface which in
Also in the second embodiment, the apparatus 1 may comprise one or more sensors 50, which may be located on the frame 2 and which communicate with the control unit 100. Sensor 50 is configured to detect a value of a parameter which may be the height of the product hosted in or on a support or directly the extent of protrusion Hp of a product beyond a top rim 4c of support 4 or the total height support plus product. The sensor 50 is configured to issue a signal for the control unit linked to the detected value of the mentioned parameter and the control unit is configured to receive said signal, and command the relative motion of the peripheral body 90 with respect to the head 36 by distance Hc equal to or greater than said extent of protrusion Hp, in order to configure the cavity 40 with a height at least sufficient to host the protruding portion of the product P.
As explained for the first embodiment, the control unit is configured to warm the active surface 37 up to an operating temperature (see first embodiment in this regard, the heating means 60 in the second embodiment may present same design as those of the first embodiment—obviously heating means 60 are operative both at both upper tools 21′ and 21″) before initiating the deformation process of the film sheet. In other words, before causing the film portion 18a to move inside the cavity 40 and take the said substantially tri-dimensional configuration, the control unit activates the heating means and brings the active surface to the operating temperature appropriate to the film structure and material under deformation. Heating of the film also increases the ability of the film to receive pronounced deformation and causes at least the peripheral film portion to better stick to the terminal surface 95.
As for the first embodiment, the heating means are controlled by the control unit 100 which is configured for regulating the heating means such that the active surface of the head 36 is brought at least to an operating temperature comprised between 150° C. and 260° C., optionally between 180-240° C., more optionally between 200-220° C. One or more temperature sensors or one or more thermal switches may be positioned in correspondence or in proximity of head 36 in order to provide the control unit with a feedback signal and allow control of the active surface temperature within the above ranges. In accordance with a presently preferred aspect, the control unit controls the heating means such that the active surface is kept at said operating temperature during the whole packaging cycle such that as soon as the film touches the active surface it gets immediately and uniformly warmed. In an aspect the control unit 100 is configured for controlling the heating means such that the terminal surface 95 of the peripheral body 90 is kept at a temperature which is always below the operating temperature of said active surface 37: this has the advantage of setting the surface at a temperature which is appropriate for plastic deformation of the film sheet portion 18a and at the same time setting the terminal surface at a temperature which is optimal for heat peripheral edge 18b to the tray rim 4c or to the support without compromising the integrity thereof. In a variant, the heating means may comprise a main heating body 61 (which may take any appropriate shape and a sufficiently big thermic mass and may host a heat source) conductively connected to the head 36 such that the control unit may heat the main heating body which on its turn heats the head 36. The main heating body may be associated to a side of the head opposite the active surface 37, or it may be otherwise thermally connected to the head 36.
The control unit is configured to bring the active surface 37 of head 36 at said operating temperature before initiating the deformation process of the film sheet. In other words, before causing the film portion 18a to move inside the cavity 40 and take the said substantially tri-dimensional configuration, the control unit activates the heating means and brings the active surface to the operating temperature appropriate to the film structure and material under deformation. Heating of the film increases the ability of the film to receive pronounced deformation and causes at least the peripheral film portion to stick to the terminal surface 95. As the active surface is kept at a uniform and substantially constant temperature, the film is uniformly heated and brought to optimal conditions for deformation.
Once the film portion 18a has been properly deformed and brought inside the cavity 40, then displacement mechanism may cause—under the control of control unit 100, movement of the upper tool 21′ to the position shown in
Once the chamber 24 has been closed, a vacuum arrangement 27 may be operated by the control unit (
Once a desired state of vacuum is reached inside the chamber 24, and after the peripheral portion of the film sheet has been sealingly fixed to the support or tray rim 4c, the control unit 100 commands the holding means 38 to release the film portion 18a: this may be achieved by commanding selector valve 42 to switch to the vent line 43 (or by appropriately positioning valves 42a, 42b). The vacuum causes the film 18 to drape down to the tray and to form a skin around the product also attaching to the tray surface not occupied by the product (
Note while the upper tool 21′ is executing the closure of the vacuum chamber and the application of the plastic film sheet to the tray (
A third embodiment is shown in
In this third embodiment, a continuous film 10a is fed to the packaging assembly 8 from a film supplying assembly 5, which may include at least one film roll 10. The cutting station 6 is located inside the packaging assembly 8 and in particular it is carried by the upper tool 21: according to this third embodiment the cutting station is configured to cut a portion of film out of the continuous film after said portion of film has been fixed to the respective tray and before the tray is extracted from the assembly 8.
Note that trays or supports 4 are supplied to the packaging assembly 8 by means of a conveyor (not shown) for instance of the type disclosed in connection with
The packaging assembly 8 is configured for tightly closing said one or more supports 4 with said film 10a and includes a lower tool 22 comprising a prefixed number of seats 23 for receiving said one or more supports 4, and an upper tool 21 facing the lower tool 22; also in this case the upper tool and the lower tool 21 and 22 are configured to be movable the one relative to the other between at least a first operating condition, where the lower tool and the upper tool are spaced apart and allow positioning of the supports 4 at said seats 23 (see
The upper tool 21 comprises a housing 120 and head 36 located inside the housing 120 and having a respective active surface 37 configured for receiving a film portion 10b of said film 10 (
A peripheral body 90, also located in housing 120, is positioned around the head 36. The peripheral body 90 may present an annular conformation and is mounted to the head 36 such that the head 36 and the peripheral body 90 may move one relative to the other. In the example shown the peripheral body stands still during creation of cavity 40, while movement is imparted to the head 36. In practice, after the film portion 10b has been blocked by frame 110, the peripheral body 90 is displaced with respect to the head 36 or the head is displaced with respect to the peripheral body (see
As already mentioned the apparatus also includes the control unit 100 which is configured for commanding the main actuator 33 and the dedicated actuator 94 and thus cause the trapping of film 10a and then the relative motion of the peripheral body 90 with respect to the head 36 in order to define said cavity 40: for instance the control unit may control the main actuator and/or the dedicated actuator to bring and stably keep for several seconds the peripheral body and the head in one of said relative positions such that the cavity 40 is formed and kept unchanged for the time necessary to apply the film to the respective tray or support 4. The relative movement between the head 36 and the peripheral body 90 is controlled by control unit such as to cause a relative displacement from an end stroke position, where a terminal surface 95 of the peripheral body 90 is aligned or substantially aligned with the active surface 37 of the head 36 (
As shown in the figures the apparatus according to the third embodiment includes holding means 38 (
The control unit 100 is configured for activating holding means 38 and is capable of coordinating the relative motion between peripheral body and head with the activation of the holding means 38 such as to cause said film portion 10b to move from a substantially flat configuration outside said cavity to a substantially tri-dimensional configuration inside said cavity 40 (see
The control unit 100 commands activation of the holding means 38 before or contemporaneously with forming of the cavity 40 such that, while the cavity is formed, the film portion 10b is pulled and stretched by the holding means moving from a substantially flat configuration to a substantially tri-dimensional configuration inside said cavity. Alternatively, as shown in
Thus, the control unit 100 may control activation of the holding means 38 such as to cause pulling of said film portion 10b inside said cavity 40 and shaping of said film portion 10b to the shape of the cavity 40, conferring a quite pronounced deformation to the interested film portion, while the film 10a is blocked between frame 110 and abutment surface 120. The head 36 may comprise a flat active surface 37 and a prismatic or cylindrical side surface 37a perpendicular to the active surface 37: consequently, as the peripheral body 90 is configured to slide along the head 36, the peripheral body comprises an inner wall 92 with a surface which is shaped as the side surface 37a of the head 36, thereby defining a cavity of cylindrical or prismatic shape. Thus, the portion of film sheet undergoing deformation may be compelled to take exactly the shape of the cavity and is therefore substantially stretched and deformed particularly in the area of the film sheet close to terminal surface 95 of the peripheral body.
Also in this third embodiment, the apparatus 1 comprises one or more sensors 50 (see
According to another aspect, the apparatus 1 includes heating means 60 configured to heat at least the active surface 37 of the head 36. The heating means may include resistances or inductances or printed circuits or other type of heaters located inside the head 36 or in proximity the active surface 37 and controlled by the control unit 100 which is configured for regulating the heating means such that the active surface of the head 36 is brought at least to an operating temperature comprised between 150° C. and 260° C., optionally between 180-240° C., more optionally between 200-220° C. One or more temperature sensors or one or more thermal switches may be positioned in correspondence or in proximity of head 36 in order to provide the control unit with a feedback signal and allow control of the active surface temperature within the above ranges. In an aspect the control unit 100 is configured for controlling the heating means such that the terminal surface 95 of the peripheral body 90 is kept at a temperature which is always below the operating temperature of said active surface: this has the advantage of setting the surface at a temperature which is appropriate for plastic deformation of the film portion 10b and at the same time setting the terminal surface at a temperature which is optimal for heat sealing portion 10b to the tray rim 4c without compromising the integrity thereof. In a variant, as shown in
The control unit is configured to bring the active surface at said operating temperature before initiating the deformation process of the film sheet. In other words, at least before causing the film portion 10b to move inside the cavity 40 and take the said substantially tri-dimensional configuration, the control unit 100 activates the heating means 60 and brings the active surface to the operating temperature appropriate to the film structure and material under deformation. In accordance with an aspect the control unit 100 is configured to permanently keep the temperature of the active surface at said operating temperature across a plurality of packaging cycles.
Once the film portion 10b has been properly deformed and brought inside the cavity 40, then main actuator or a further actuator 130 associated to the lower tool may cause—under the control of control unit 100, movement from said first operating condition (
Once the chamber 24 has been closed, a vacuum arrangement 27 may be operated by the control unit (
The cycle described above may then be repeated.
The apparatus 1 of the third embodiment may also, or may alternatively, include a controlled atmosphere arrangement 30 connected to the packaging chamber 24 and configured for injecting a gas stream into said packaging chamber; the controlled atmosphere arrangement comprises at least one injection device including an injection pump and/or one injection valve 31 connecting the inside of said chamber 24 to the source of gas (not shown) which may be located remotely from the apparatus 1; the control unit 100 may be configured to control opening and closing of the injection valve (or activation of the injection pump) to inject said stream of gas at least when the packaging assembly 8 is in said second operating condition, i.e. with said packaging chamber 24 hermetically closed.
Although the apparatus 1 may have one or both the vacuum arrangement 27 and the controlled atmosphere arrangement 30, it is to be understood that the control unit 100 of the apparatus 1 may also be configured to tightly engage the film sheets 18 to the trays without activating the vacuum arrangement or the controlled atmosphere arrangement and thus leaving the normal environment atmosphere within the tray. This may be for instance the case for non perishable products. Thus in a version, the apparatus 1 may be designed without vacuum arrangement and without modified atmosphere arrangement.
A fourth embodiment is shown in
In the fourth embodiment, a continuous film 10a is fed to the packaging assembly 8 from a film supplying assembly 5, which may include at least one film roll 10. The cutting station is not shown and—if present—may for instance be located downstream the packaging assembly and intervene on the packaged products. A tray supply assembly 140 is configured for supplying a continuous web 141 including a plurality of thermoformed supports 4 in the form of interconnected trays: the tray supply assembly may include a transport means e.g. acting on the longitudinal borders of the web: chains with pincers may be used or driving rollers or other suitable means controlled by the control unit 100. The tray supply assembly, the film supply assembly and the packaging assembly may be carried by a fixed frame 2.
The packaging assembly 8 is configured for tightly closing said supports 4 with said film 10a and includes a lower tool 22 comprising a prefixed number of seats 23 for receiving said thermoformed supports 4, and an upper tool 21 facing the lower tool 22; also in this case the upper tool and the lower tool 21 and 22 are configured to be movable the one relative to the other between at least a first operating condition, where the lower tool and the upper tool are spaced apart and allow positioning of the supports 4 inside the packaging assembly, and a second operating condition, where the lower tool and the upper tool delimit a packaging chamber 24 (see
The control unit 100 is configured to cause the film tray supply assembly to move the continuous web 141 into the packaging assembly 8: as it can be seen a portion of web 141a including a plurality of supports 4 is brought at each time inside the packaging assembly between the upper and lower tools 21, 22. At the same time the control unit is configured to move a corresponding film portion or length 10b of the continuous film 10a into the packaging assembly 8. The film supply assembly 5 and the packaging assembly 8 are configured and relatively positioned such that the film length 10b is fed to the packaging assembly 8 at an acute angle α with respect to the horizontal, as shown e.g. in
The control unit controls the cinematic structure to first bring the upper tool in contact with a leading section 10c of the continuous film closer to the film supply assembly compared to the portion 10b of film located above the support or trays in the packaging assembly 8, as it is further disclosed herein below.
Also in the fourth embodiment, the upper tool 21 comprises head 36 having a respective active surface 37 configured for receiving said film length 10b and a peripheral body 90 positioned around the head 36. The peripheral body 90 may present an annular conformation and is mounted to the head 36 such that the head 36 and the peripheral body 90 may move one relative to the other. In practice, after the upper tool—under the action of cinematic structure 150 controlled by control unit 100—is rotated from the position of first contact with the film (
As shown in
The control unit 100 is configured for activating holding means 38 and is capable of coordinating the relative motion between peripheral body and head with the activation of the holding means 38 such as to cause said film length 10b to move from a substantially flat configuration outside said cavity to a substantially tri-dimensional configuration inside said cavity 40 (see
The control unit 100 commands activation of the holding means 38 before or contemporaneously with forming of the cavity 40 such that, while the cavity is formed, the film length 10b is pulled and stretched by the holding means moving from a substantially flat configuration to a substantially tri-dimensional configuration inside said cavity. Alternatively, as shown in
Thus, the control unit 100 may control activation of the holding means 38 such as to cause pulling of said film length 10b inside said cavity 40 and shaping of said film length 10b to the shape of the cavity 40, conferring a quite pronounced deformation to the interested film length, while the film 10a is blocked as both the film supply assembly is stopped in this phase and as the film, downstream the packaging assembly is stably fixed to the supports. The head 36 may comprise a flat active surface 37 and a prismatic or cylindrical side surface 37a perpendicular to the active surface 37: consequently, as the peripheral body 90 is configured to slide along the head 36, the peripheral body comprises an inner wall 92 with a surface which is shaped as the side surface 37a of the head 36, thereby defining a cavity of cylindrical or prismatic shape. Thus, the portion of film sheet undergoing deformation may be compelled to take exactly the shape of the cavity and is therefore substantially stretched and deformed particularly in the area of the film sheet close to terminal surface 95 of the peripheral body.
Also in this fourth embodiment, the apparatus 1 may comprise one or more sensors 50 (
According to another aspect, the apparatus 1 includes heating means 60 configured to heat at least the active surface 37 of the head 36. The heating means may include resistances or inductances or printed circuits or other type of heaters located inside the head 36 or in proximity the active surface 37 and controlled by the control unit 100 which is configured for regulating the heating means such that the active surface of the head 36 is brought at least to an operating temperature comprised between 150° C. and 260° C., optionally between 180-240° C., more optionally between 200-220° C. One or more temperature sensors or one or more thermal switches may be positioned in correspondence or in proximity of head 36 in order to provide the control unit with a feedback signal and allow control of the active surface temperature within the above ranges. In an aspect the control unit 100 is configured for controlling the heating means such that the terminal surface 95 of the peripheral body 90 is kept at a temperature which is always below the operating temperature of said active surface: this has the advantage of setting the surface at a temperature which is appropriate for plastic deformation of the film sheet portion 10b and at the same time setting the terminal surface at a temperature which is optimal for heat sealing without compromising the support integrity.
The heating means are preferably activated by the control unit such as to constantly keep the active surface at said operating temperature. Thus, the control unit 100 activates the heating means 60 and brings the active surface to the operating temperature appropriate to the film structure and material under deformation before starting the packaging cycles and typically makes sure the active surface remains at said operating temperature. Heating of the film increases the ability of the film to receive pronounced deformation and causes at least the peripheral film portion to stick to the terminal surface 95.
Once the film portion 10b has been properly deformed and brought inside the cavity 40, then cinematic structure 150 or a further actuator 130 associated to the lower tool may cause—under the control of control unit 100—movement from said first operating condition (
Once the chamber 24 has been closed, a vacuum arrangement 27 may be operated by the control unit (
The cycle described above may then be repeated.
The apparatus 1 of the fourth embodiment may also, or may alternatively, include a controlled atmosphere arrangement 30 connected to the packaging chamber 24 and configured for injecting a gas stream into said packaging chamber; the controlled atmosphere arrangement comprises at least one injection device including an injection pump and/or one injection valve 31 connecting the inside of said chamber 24 to the a source of gas (not shown) which may be located remotely from the apparatus 1; the control unit 100 may be configured to control opening and closing of the injection valve (or activation of the injection pump) to inject said stream of gas at least when the packaging assembly 8 is in said second operating condition, i.e. with said packaging chamber 24 hermetically closed.
Although the apparatus 1 may have one or both the vacuum arrangement 27 and the controlled atmosphere arrangement 30, it is to be understood that the control unit 100 of the apparatus 1 may also be configured to tightly engage the film sheets 18 to the trays without activating the vacuum arrangement or the controlled atmosphere arrangement and thus leaving the normal environment atmosphere within the tray. This may be for instance the case for non perishable products. Thus in a version, the apparatus 1 may be designed without vacuum arrangement and without modified atmosphere arrangement.
The apparatus according to the invention has at least one control unit.
The control unit 100 (schematically represented in
In general terms the control unit 100 acts on and controls the active components present in the apparatuses of any one of the above described embodiments, namely (where present) the transport assembly 3, the film cutting assembly 6, the transfer device, the packaging assembly 8 and particularly the upper and/or lower tools 21, 22, the vacuum arrangement 27, the controlled atmosphere arrangement 30 and the other actuators described above.
The control unit may also be configured for controlling the apparatus 1 in order to execute any one of the packaging processes described above or claimed in the appended claims.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and the scope of the appended claims.
For instance, the specific nature of the actuators described is exemplificative and alternative types of actuators may be used provided the type of motion imposed to the mobile parts on which said actuators are operating is the same. Also note that although the described embodiments show a single packaging being produced per time in embodiments 1-3, multiple packaging assemblies may be used in parallel in order to optimize productivity.
| Number | Date | Country | Kind |
|---|---|---|---|
| 13197353.9 | Dec 2013 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP14/77844 | 12/15/2014 | WO | 00 |
