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Title:
HEAT-SEALING MACHINE WITH ALVEOLI FOR SEALING CONTAINERS IN MODIFIED ATMOSPHERE
Document Type and Number:
WIPO Patent Application WO/2019/229661
Kind Code:
A1
Abstract:
Heat-sealing machine (100) with alveoli for sealing containers (150) in modified atmosphere, comprising a cam system with: - a central arm (122) connected to a reducer (124) driven by a motor (101) in a rotary movement; - an upper arm (121), connected to an end of the central arm (122) and with a rigid structure for the displacement of the lower bell-shaped element (112) of the sealing tower (110); - a lower arm (123), connected to the other end of the central arm (122) and with the upper bell-shaped element (111); said cam system (120) simultaneously controlling said upper bell-shaped element (111) and said lower bell-shaped element (112) in approaching movement in order to pass from the first open configuration to the second closed configuration and moving-apart movement in order to pass from the second closed configuration to the first open configuration, due to the inversion of the direction of rotation of the reducer (124) connected to said central arm (122) and controlled by said motor (101).

Inventors:
MARANO ANGELO (IT)
MARANO FABIO (IT)
Application Number:
PCT/IB2019/054428
Publication Date:
December 05, 2019
Filing Date:
May 29, 2019
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
AMC S R L (IT)
International Classes:
B29C65/02; B29C65/74; B29C65/78; B65B7/16; B65B31/02; B65B51/14
Foreign References:
EP0483569A11992-05-06
US3283469A1966-11-08
DE202010018313U12015-07-14
US3775932A1973-12-04
US4989393A1991-02-05
Attorney, Agent or Firm:
FIAMMENGHI, Eva et al. (IT)
Download PDF:
Claims:
Claims

1. Heat-sealing machine (100) with alveoli for sealing containers (150) in modified atmosphere, said machine (100) being of the linear type with catenary consisting of a plurality of strips (130), each strip (130) comprising at least one alveolus (131) suitable to be engaged with a corresponding container (150) to be sealed which is transferred to at least one sealing tower (110) in which an upper bell-shaped element (111) and a lower bell-shaped element (112) are suitable to reversibly take a first open configuration and a second closed configuration; in said first open configuration, said bell-shaped elements (111-112) being vertically spaced to centrally receive said strip (130) with said container

(150); in said second closed configuration, said bell-shaped elements (111-112) being at contact with each other, comprising said strip (130) therein, in order to seal a plastic film (140) at the edge of each container (150) and cut said plastic film (140) by means of common blades; said upper bell-shaped element (111) and said lower bell-shaped element (112) being controlled by a mechanical displacement system (120) connected to a motor (101) installed on board said machine (100); said machine (100) being characterised in that said displacement system (120) is a cam system (120) comprising

- a central arm (122) connected, at the centre thereof, to a reducer (124) driven by said motor (101) in a rotary movement that is transmitted said central arm (122); said central arm (122) being connected at one end thereof to an upper arm (121) and at the second end to a lower arm (123);

- said upper arm (121), connected at one end with said central arm (122) and at the opposite end with a rigid structure for displacing said lower bell-shaped element (112) through a telescopic system of bars of said sealing tower (110);

- a lower arm (123), connected at one end with said central arm (122) and at the opposite end with said upper bell-shaped element (111);

said cam system (120) being suitable to simultaneously control said upper bell-shaped element (111) and said lower bell-shaped element (112) in approaching movement in order to pass from the first open configuration to the second closed configuration and moving-apart movement in order to pass from the second closed configuration to the first open configuration, due to the inversion of the direction of rotation of said reducer (124) connected to said central arm (122) and controlled by said motor (101).

2. Heat-sealing machine (100) with alveoli for sealing containers (150) in modified atmosphere, according to the preceding claim 1, characterised in that said motor (101) is suitable to impart to said reducer (124) the maximum acceleration in the central portion of the stroke thereof and a braking in proximity to reaching the end-stroke, so as to determine a soft contact between the upper bell-shaped element (111) and the lower bell-shaped element (112) when the latter are in said second closed configuration; said motor (101) being of brushless type.

3. Heat-sealing machine (100) with alveoli for sealing containers (150) in modified atmosphere, according to any one of the preceding claims 1 or 2, characterised in that it is provided with a common vacuum pump suitable to suction air from within the containers (150) housed in the respective alveoli (131) when the latter are in the sealing tower (110), before being sealed with the plastic film (140). 4. Heat-sealing machine (100) with alveoli for sealing containers (150) in modified atmosphere, according to any one of the preceding claims, characterised in that it is provided with a common gas injection system suitable to introduce a predetermined quantity of a gas mixture pre-formed in the containers (150) housed in the respective alveoli (131) when the latter are in the sealing tower (110), before being sealed with the plastic film (140).

5. Heat-sealing machine (100) with alveoli for sealing containers (150) in modified atmosphere, according to any one of the preceding claims, characterised in that it comprises a plurality of sealing towers (110).

6. Heat-sealing machine (100) with alveoli for sealing containers (150) in modified atmosphere, according to any one of the preceding claims, characterised in that each strip (130) comprises a plurality of alveoli (131), also having different shapes, also on alternating strips.

7. Strip (130) for a heat-sealing (100) for sealing containers (150) in modified atmosphere, consisting of at least one alveolus (131) suitable to be engaged with the edge of a container (150) to be sealed and transfer it towards a sealing tower (110) of a packaging machine (100); said strip (130) being characterised in that each alveolus (131) is consists of an outer edge (132) and an inner edge (133) spaced from each other by an interspace (134) closed at the bottom; said inner edge (133) being suitably shaped in order to be engaged with the upper edge of said container (150) to be sealed and being at a lower height with respect to said outer edge (132); when said strip (130) is in said sealing tower (110) while the two bell-shaped sealing elements are closed, comprising, between them, said strip (130) and the plastic film (140) with which the container (150) is to be sealed, the assembly consisting of the outer edge (132), outer wall (136) of said outer edge (132), bottom closure of the interspace (134), inner edge (133) and container (150) form an air chamber closed at the top by said plastic film (140) which is yet to be sealed on the edge of the container (150); before said sealing, a predetermined amount of a gas or a pre-formed gas mixture being introduced by means of at least one introduction hole (135) arranged on said lateral wall (136) of said interspace (134) in order to facilitate the introduction of gas into the containers (150).

8. Strip (130) for a heat-sealing machine (100) for sealing containers (150) in modified atmosphere, according to the preceding claim 7, characterised in that it comprises a plurality of alveoli (131).

9. Strip (130) for a heat-sealing machine (100) for sealing containers (150) in modified atmosphere, according to any one of the preceding claims 7 or 8, characterised in that each alveolus (131) is provided with holes for removing air, connected to a common vacuum pump.

10. Heat-sealing machine (100) with alveoli for sealing containers (150) in modified atmosphere, according to any one of the preceding claims 1 to 6, characterised in that it comprises a catenary consisting of strips (130) according to any one of the preceding claims 7 to 9.

Description:
“Heat-sealing machine with alveoli for sealing containers in modified atmosphere”

Description Field of the art

The present invention regards the field of heat-sealing machines for sealing containers of any type, for example food grade containers. In particular, the heat-sealing machines to which the patent refers to are of the linear type and with strips catenary and alveoli. Prior art

The packaging industry is currently one of the most technologically advanced industries. Considering the ever-growing demand for packaged products of any type, in particular food grade products, for large-scale distribution in supermarkets, machines for sealing containers must operate at extremely high speeds and with incredibly high efficiency.

Each malfunction entails machine downtime which could lead to serious losses for the company in terms of logistics and turnover. Having to shut down the machine for repair works thereon, even for a short time interval, would entail losing hundreds of unsealed containers and the product cannot be recovered in most cases.

The object of the present invention is a special application on a heat-sealing machine for preformed containers that produces packages with modified atmosphere (in the technical jargon referred to as MAP) at an extremely high speed and with low mechanical impact. In order to modify the air or atmosphere in such containers, generally used are machines with two hollow bell-shaped elements, an upper one and a lower one, which approach each other forming a single air-tight sealed bell-shaped element and within which, before carrying out the sealing of the film, initially carried out is a vacuum condition by means of common vacuum pumps and they are subsequently filled with modified air, generally deprived of oxygen, or other gas mixtures; an action that has the purpose of extending the date of preservation of the food products without using preservatives or chemical agents in that the bacteria that feed on oxygen tend to reproduce more slowly in the absence of oxygen This technique commonly known as“vacuum-gas” is widely used across the world. However, in linear heat-sealing machines with alveoli catenary (i.e. high production performance machines) such process is further complicated by the structure of the strips and by the difficulty of introducing modified gas (after the vacuum step) into the trays in quick and uniform manner.

At industrial patent level the industry is rather crowded, both at national and international level. A considerable number of recent filings regard machines which seal containers under vacuum, such as for example the patent extended with the PCT procedure n° WO 2018 069 880.

Patent n° WO 2016 055 599 instead claims a specific heat-sealing machine for packaging frozen meat.

WO 2014 166 940 regards a machine for packaging food in plastic containers in modified atmosphere which is configured to obtain the least waste possible of the plastic film used for sealing.

Though some of the machines available in the market are capable of packaging with the MAP system, they are not entirely free of drawbacks and above all none of them are linear heat-sealing machines with alveoli strips, i.e. a type of high production type of packaging machines.

A first production problem lies in the impacts due to contact of the upper and lower airtight sealed bell-shaped elements against each other during the sealing operations in the sealing tower given the high speeds at which they are required to operate so as to maintain the high productivity of this type of packaging machines. Such displacements are generally driven by two pneumatic pistons or by two independent motors (one for the upper bell-shaped element and the other for the lower bell-shaped element). This also entails the higher probability of failures or malfunctioning of the machine and the higher need for maintenance.

A second drawback of these systems lies in the current difficulty to obtain a homogeneous distribution of the insufflated gas (MAP) in the airtight bell-shaped element in which the containers to be sealed are contained and more precisely in the containers; this due to the strips system which, besides having particular shape, must necessarily be included in the bell-shaped elements when the latter are closed and vacuum is created. In this step, the position of the film above the containers interferes with the free through-flow of air in that it cannot be regulated height-wise like it occurs in all heat-sealing machines that do not operate with strips.

An object of the present invention is to provide a heat-sealing machine that overcomes all the aforementioned drawbacks and simultaneously increases the production speed of the heat-sealing machines with alveoli of any type.

Description of the invention

Provided according to the present invention is a heat-sealing machine with linear alveoli strips for sealing packages in modified atmosphere for effectively resolving the problems outlined above.

Advantageously, the present invention regards a heat-sealing machine of the linear type and even more in detail heat-sealing machines provided with a strips catenary in which each strip consists of at least one alveolus, preferably a plurality of alveoli, each of which suitable to transfer a container to be sealed to the sealing tower where the process occurs.

As known to a man skilled in the art, the sealing occurs by closing a lower bell-shaped element and an upper bell-shaped element (closed configuration) at the strip also comprising the plastic film used to close the container at the top part. Upon pressing the film and thus upon adhering it to the upper edge of the container, it is sealed by applying heat, and a cutting tool is used to cut the plastic film; the two bell-shaped elements take an open configuration and the catenary advances to remove the strips with the already sealed containers from the sealing tower and so as to allow the entry of the strips with the containers yet to be sealed; in the meanwhile, the trimmed film is rewound advancing a new film to be sealed.

The present invention applies, with the same advantages, to machines with one or more sealing towers and with strips provided with one or more alveoli.

Furthermore, it can be applied with strips equipped with mixed alveoli of different shapes or with strips each alternating with one or more different shapes of trays so as to obtain change of format versatility too besides the speed.

Advantageously, the system for the displacement of the bell-shaped elements (upper and lower) is of the mechanical cam type and it consists of at least:

- one central arm connected, at the centre thereof, to a reducer driven by a motor in a rotary movement which is transmitted to said central arm;

- an upper arm, connected at an end thereof to an end of the central arm and with the opposite end with a rigid structure for displacing the lower bell-shaped element;

- a lower arm, connected at an end thereof to the other end of the central arm (122) and with the opposite end to the upper bell-shaped element.

The advantage obtained from this cam system lies in the simultaneous control of said upper bell-shaped element and said lower bell-shaped element in the approaching movement to pass from the first open configuration to the second closed configuration and in the moving- apart movement to pass from the second closed configuration to the first open configuration. Hence, the reducer which imparts the movement to the central arm and thus to the bell- shaped elements, must be controlled by a motor which alternates the direction of rotation thereof. More in detail, said motor, in the preferred embodiment of the present invention, will be suitable to impart to said reducer the maximum acceleration in the central portion of the stroke thereof and a braking in proximity of reaching the end-stroke so as to determine a soft contact between the upper bell-shaped element and the lower bell-shaped element when the latter are in said second closed configuration. A further optimisation of this process is obtained by using brushless motors by means of which the accelerations and rotation speeds of the axes can be programmed as desired by the manufacturer.

The cam system is created with the aim of obtaining the same movement of the two sealing bell-shaped sealing elements with a mechanical slow-down at the most sensitive moment i.e. in the last centimetres where the coupling of the upper and lower bell-shaped sealing elements occurs, reducing the knock impact to the least possible while maintaining high cycle speed.

Advantageously, said motor will thus be of the brushless type, further avoiding strong impacts between the bell-shaped elements of the machine and thus extending the life of each component thereof, without losing speed and thus performance drop of the machine.

As regards the strips which constitute the catenary of the machine subject of the present invention, they are also subject of the innovations introduced by this patent.

In particular, they are advantageously provided with one or more alveoli each of which consisting of an outer edge, higher, son which the film lies when closing the bell-shaped elements, and an inner edge, lower, on which the edge of the container lies. Such height difference allows the formation of an air chamber for the removal of air, during a step for creating vacuum and the subsequent introduction of gas in an insufflation step, by means of an interspace closed at the bottom part and communicating with the gas channels through one or more communication holes. The dimensions of the inner edge are selected to allow the engagement with the upper edge of the container to be sealed.

The creation of this air chamber allows both the suctioning of air by means of a common vacuum pump with which the machine is advantageously equipped and the introduction, before the sealing of the plastic film on the container, of a predetermined amount of a gas or a pre-formed gas mixture. A similar machine is referred to in the technical jargon by the name“vacuum-gas” and the gas mixture which is introduced is generally without oxygen to delay the expiration of the products preserved in the container.

Said gas is advantageously introduced into the previously described air chamber, by means of at least one hole, preferably a pair of holes, or several holes for introducing gas arranged at the outer wall of the interspace.

The advantages provided by the present invention will be clear in light of the description outlined up to now. Furthermore, they will be more apparent due to the attached figures and relative detailed description. Description of the figures

The invention will be described hereinafter in at least one preferred embodiment, provided by way of non-limiting example, with reference to the attached figures, wherein: - FIGURE 1 shows the machine 100 in the first open configuration, wherein the upper 111 and lower 112 bell-shaped element of the sealing tower 110 are spaced to allow the transit of the strips 130 which transfer the containers 150.

- FIGURE 2 illustrates the same machine 100 in the second closed configuration, wherein the plastic film 140 is locked between the two sealing bell-shaped elements 111-112 and forced to lie on the upper edge of the alveoli 131 where the containers 150 present in the sealing tower 110 are housed.

- FIGURE 3 shows a strip 130, according to the present invention, provided with four alveoli 131 for four corresponding containers 150.

- FIGURE 4 illustrates, from a closer view, the internal organisation of each alveolus 131 with an outer edge 132, higher than an inner edge 133 and an interspace 134 between the two.

- FIGURE 5 shows a cross-sectional view of the internal distribution of the alveolus 131 which clearly shows the two gas introduction holes 135-135’, on the outer wall 136 of the interspace 134.

Detailed description of the invention

Now, the present invention will be illustrated purely by way of non-limiting or non-binding example, with reference to the figures illustrating some embodiments regarding the present inventive concept.

Shown with reference to FIGS. 1 and 2 are respectively the first open configuration and the second closed configuration of heat-sealing machine 100 according to the preferred embodiment of the present invention.

This is a linear machine 100 with strips catenary 130 with alveoli 131.

With the aim of simplifying the representation shown is only one sealing tower 110, with an upper bell-shaped element 111 and a lower bell-shaped element 112, and with strips 130 provided with only one row of four alveoli 131. This does not limit the application of the present invention to a machine 100 with several sealing towers 110 and strips 130 with several rows of alveoli 131 or alternating rows of differently shaped alveoli 131 in any manner whatsoever.

Additionally, the machine 100 represented in the aforementioned figures, is of the“vacuum- gas” type, i.e. it is provided with a common vacuum pump and with a gas reservoir. The removal of air and the replacement thereof with a modified atmosphere, without oxygen (or other type of gas or gas mixture), serves to extend the expiration date of the food products and this is why such type of machine is preferred when sealing food grade containers 150. The operation of the cam-equipped displacement system 120 which characterises the machine 100 in question can be observed in the first two attached figures.

Besides the brushless motor 101, which controls the reducer 124 which generates a rotation of a shaft orthogonally to the rotation axis of the motor 101 with the maximum acceleration in the central portion of the stroke thereof and a braking in proximity of reaching the end- stroke (thanks to the mechanics of the cams), shown is a central arm 122 connected, at the centre thereof, to said reducer 124. The central arm 122 is in turn connected, at an end thereof, with an end of an upper arm 121 and, at the other end, said central arm 122 is connected with an end of a lower arm 123.

Thus, the upper arm 121 has the other end (i.e. the end free from the central arm 122) connected with a rigid structure for displacing the lower bell-shaped element 112 of the sealing tower 110.

The lower arm 123, instead, has the other end (i.e. the end free from the central arm 122) connected with the upper bell-shaped element 111 of the sealing tower 110. The open configuration and closed configuration are represented in FIGS. 1 and 2 and the technological components suitably studied and herein described reveal advantages, innovative for the type of machines 100 in question, of the sensitive and simultaneously extremely accurate and quick contact between the two bell-shaped elements 111-112 which constitute the sealing tower 110, also avoiding the risk of non-simultaneous couplings between the upper and lower bell-shaped elements, given that this could damage the machine 100 in the long-term.

In the“vacuum-gas” machines 100 it is very important for the contact between the two bell shaped elements 111-112 to be exactly replicated for each sealing cycle in that it is necessary to create the vacuum in the alveoli 131 which carry the containers 150 and then introducing the protective atmosphere before the sealing.

In the present invention, the particular shape of the alveoli 131 is represented in FIGS. 3, 4 and 5 in an increasingly detailed manner.

Each alveolus 131 consists of an outer 132, at a higher height, and an inner edge 133 at a slightly lower height. The container 150 designated for each alveolus 131 will be arranged at the inner edge 133.

Thus, present between the outer 132 and inner edge 133 is an interspace 134 which is closed at the bottom part by a bottom element and laterally by at least one lateral wall 136 which constitutes the vertical extension, towards the bottom, of the outer edge 132. Such design may have a variable shape depending on the shape of the container 150 pre-selected by the customer.

Let us examine a strip 130 consisting of these alveoli 131 located inside said sealing tower 110 while the two sealing bell-shaped sealing elements 111-112 are closed comprising, between them, said strip 130 and the plastic film 140 to be used to seal the container 150. In this configuration, the assembly consisting of the outer edge 132, outer wall 136 of said outer edge 132, bottom closure of the interspace 134, inner edge 133 and container 150, creates an air chamber closed at the top part by said plastic film 140 when the latter is yet to be sealed of the edge of the container 150. Such air chamber firstly allows to remove the air to create the vacuum, by means of a common vacuum pump and, subsequently, the introduction of the protective atmosphere by means of a pair of introduction holes 135-135’ arranged on said lateral wall 136 of the interspace 134.

Lastly, it is clear that the invention described up to now may be subjected to modifications, additions or variants obvious to a man skilled in the art, without departing from the scope of protection outlined by the attached claims.