Heat-sealing machine

Abstract

A heat-sealing machine for sealing a plurality of individual trays with a plastic film and which is configured to create a vacuum between the trays and the plastic film. The machine includes an upper sealing assembly and a lower sealing assembly movable with respect to the upper sealing assembly. The lower sealing assembly being moveable between a rest position and a cooperating position. There being a vacuum chamber delimited between the lower and upper sealing assemblies when the lower sealing assembly is in the rest position. The vacuum chamber being connectable to an extraction circuit. The lower sealing assembly includes a tray frame with a plurality of tray cavities with each tray cavity being configured to receive a respective tray. The vacuum chamber being delimited between the tray frame and the upper sealing assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application relates to and claims the benefit and priority to European Patent Application No. 25382301.7, filed Mar. 28, 2025, which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present invention relates to heat-sealing machines.BACKGROUND

[0003] In heat-sealing machines, products are packaged into trays as a result of sealing a plastic film to the trays containing the products. This type of machine comprises a lower sealing assembly and an upper sealing assembly facing each other and configured to cooperate with each other to perform the sealing. The lower sealing assembly can be moved between a resting position, in which it is vertically distanced apart from the upper sealing assembly, and a cooperating position, in which it cooperates with the upper sealing assembly to seal.

[0004] With the lower sealing assembly in the resting position, the trays with the products to be packaged are received in the lower sealing assembly. Subsequently, the lower sealing assembly is moved to the cooperating position to seal the trays and thus obtain the packaged products.

[0005] The lower sealing assembly further comprises a support plate for each tray it can receive. The support plate is used so that the tray is above the lower sealing assembly at least when the lower sealing assembly is in the resting position, whereby a tool can easily arrange the trays on the lower sealing assembly and can pick them up after the products have been packaged. The lower sealing assembly further comprises a tray positioner configured to cooperate with the support plates to cause the trays to be so positioned at least when said lower sealing assembly is in the resting position.

[0006] Sometimes it is necessary to apply a vacuum between the trays and the plastic film (in the space where the product to be packaged is), and some heat-sealing machines are configured to be able to perform this vacuum. These heat-sealing machines include an extraction circuit that communicates this space with a gas extraction source.

[0007] US2020346801A1 discloses a heat-sealing machine that is configured to be able to apply vacuum. The lower sealing assembly comprises a tray frame defining a plurality of tray cavities, each tray cavity being configured to receive a respective tray; a lower base vertically spaced from said tray frame and attached to said tray frame; a respective support plate for each tray; and a tray positioner disposed below the tray frame. In the machine, a vacuum can be created over a vacuum chamber comprising the tray cavities and which is generated when the lower sealing assembly is in the cooperating position, the machine comprising an extraction circuit that fluidically communicates a gas extraction source with the vacuum chamber.SUMMARY

[0008] Disclosed is a heat-sealing machine.

[0009] The machine is adapted to seal a plurality of individual trays with a plastic film and is configured to create a vacuum between the trays and the plastic film before sealing.

[0010] The machine comprises a sealing station with a lower sealing assembly and an upper sealing assembly vertically facing each other; an elevation mechanism configured to move the lower sealing assembly between a resting position, in which the lower sealing assembly and the upper sealing assembly are spaced apart, and a cooperating position, in which the lower sealing assembly and the upper sealing assembly cooperate with each other generating, with such cooperation, a vacuum chamber delimited between said lower sealing assembly and said upper sealing assembly; and an extraction circuit which, with the lower sealing assembly in the cooperating position, fluidically communicates a gas extraction source with the vacuum chamber.

[0011] The lower sealing assembly comprises a tray frame defining a plurality of tray cavities, each tray cavity being configured to receive a respective tray; a lower base vertically spaced from said tray frame, attached to said tray frame, to the elevation mechanism and to said tray frame; a respective support plate for each tray cavity, each support plate comprising a support base configured to support a tray and a support rod attached to the support base; and a tray positioner arranged below the tray frame and configured to cooperate with the support rods to cause, with the lower sealing assembly in the resting position, all trays supported on the respective support bases of said support plates to be arranged simultaneously above the tray frame for easy handling. The support rods extend from the corresponding support base through the tray frame, towards the plate positioner.

[0012] The tray frame is configured such that the vacuum chamber is delimited between said tray frame and the upper sealing assembly, the tray cavities being within said vacuum chamber. The support plate is associated with the tray frame such that, with the lower sealing assembly in the cooperating position, the support base rests on the tray frame, said support plate being housed in the corresponding tray cavity within the vacuum chamber. This implies that at least the part of the support rods that cooperates with the plate positioner is outside the vacuum chamber, and the cooperation between said plate positioner and the support plates is therefore performed outside the vacuum chamber.

[0013] The lower base is configured to be connected to the gas extraction source, and the extraction circuit comprises at least one connection conduit arranged between the tray frame and the lower base to fluidically communicate the vacuum chamber with the gas extraction source, through the lower base, when the lower base is connected to the gas extraction source.

[0014] Thanks to this machine configuration, the support plate maintains the function of arranging the trays above the tray frame where required, while at the same time the volume of air extracted by the gas extraction source is considerably reduced (by reducing the volume of the vacuum chamber). In the prior art, the vacuum chamber not only includes the space around the trays as in the case of the proposed machine but also includes a volume below the tray frame where the plate positioner attached to the support plates is located. This reduction achieved in the proposed machine means that less air has to be evacuated when a vacuum is performed in the vacuum chamber, which considerably reduces the time required to perform the vacuum and, therefore, the time required to perform the corresponding product packaging process. Furthermore, in the proposed machine, the type of tray (of different heights or flat) on which the plastic film is to be sealed can be easily modified, because it is possible to replace only the tray frame together with the support plates if so required, without the need to modify or replace the entire lower sealing assemblies, thus a more versatile machine being obtained and at a lower cost.

[0015] These and other advantages and features of the invention will become apparent in view of the figures and the detailed description of the invention.DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 shows an embodiment of a heat-sealing machine according to the invention.

[0017] FIG. 2 shows a sealing station of the machine of FIG. 1, with a lower sealing assembly in a resting position.

[0018] FIG. 3 shows a sealing station of the machine of FIG. 1, with a lower sealing assembly in a cooperating position.

[0019] FIG. 4 shows details of a vacuum circuit of an embodiment of the machine of the invention adapted to package products in flat trays.

[0020] FIG. 5 shows details of a vacuum circuit of an embodiment of the machine of the invention adapted to package products in trays with a given height.

[0021] FIG. 6 shows a sealing station of another embodiment of the machine of the invention, with a lower sealing assembly in a resting position.

[0022] FIG. 7 shows a position of the lower sealing assembly of the sealing station of FIG. 2 during its travel to a cooperating position, in which support plates rest on respective cavity bases of the tray cavities of a tray frame of said lower sealing assembly and are supported on a platform of a plate positioner.

[0023] FIG. 8 shows a position of the lower sealing assembly of the sealing station of FIG. 2 during its travel to a cooperating position, where the support plates rest on cavity bases of the tray cavities and are separated from the platform of a plate positioner.DETAILED DESCRIPTION

[0024] Heat-sealing machine 100, as shown by way of example in FIG. 1, is used for packaging products P. The machine 100 is adapted to seal with a plastic film 400 a plurality of trays 300, and to create a vacuum between the trays 300 and the plastic film 400 (prior to sealing).

[0025] The machine 100 comprises a sealing station 3 with a lower sealing assembly 10 and an upper sealing assembly 20 vertically facing each other, and an elevation mechanism 1000 configured to move the lower sealing assembly 10 between a resting position Pr (see FIG. 2) and a cooperating position Pc (see FIG. 3, where further details of the upper sealing assembly 20 are shown). In the resting position Pr, the lower sealing assembly 10 is vertically distanced from the upper sealing assembly 20. In the cooperating position Pc, the lower sealing assembly 10 cooperates with the upper sealing assembly 20 (no longer being vertically distanced), so that the vacuum and sealing referred to above can be performed. The machine 100 further comprises an extraction circuit 14 which, with the lower sealing assembly 10 in the cooperating position Pc, fluidically communicates a gas extraction source (not shown in the figures and that will be in the installation where the machine 100 is) with the vacuum chamber 1020 (when the machine 100 is connected to the gas extraction source), thus the vacuum to be carried out over the vacuum chamber 1020 being allowed.

[0026] The lower sealing assembly 10 comprises a tray frame 11 defining a plurality of tray cavities 11.1, each tray cavity 11.1 being configured to receive a respective tray 300; a lower base 10.1 vertically spaced from said tray frame 11 (and disposed below said tray frame 11.1), and attached to said tray frame 11 by at least one support 11.4 such that said tray frame 11.1 and lower base 10.1 move together between the resting position Pr and the cooperating position Pc. The elevation mechanism 100 is preferably attached to the lower base 10.1 (see FIGS. 2 and 3 for example), acting directly on said lower base 10.1 to cause displacement of the lower sealing assembly 10. When the vacuum chamber 1020 is generated, the tray cavities 11.1 are within said vacuum chamber 1020.

[0027] The lower sealing assembly 10 also comprises a respective support plate 13 for each tray cavity 11.1, and a tray positioner 15 arranged below the tray frame 11. Each support plate 13 comprises a support base 13.2 configured to support a tray 300, and a support rod 13.1 attached to the support base 13.2, that extends vertically from said support base 13.2 traversing the tray frame 11 towards the plate positioner 15. The tray frame 11 comprises at least one sealing gasket (not depicted in the figures) which cooperates with the support rod 13.1 to maintain the sealing of the vacuum chamber 1020. The plate positioner 15 faces the support rods 13.1 and is configured to cooperate with the support rods 13.1 to cause that, with the lower sealing assembly 10 in the resting position Pr, all trays 300 supported on the support bases 13.2 of the corresponding support plates 13 are arranged above the tray frame 11 (further details of this cooperation are given below). As the support rods 13.1 traverse the tray frame 11, this cooperation takes place below the tray frame 11.

[0028] The support plates 13 are arranged in the tray frame 11 with freedom to relatively move with respect to said tray frame 11. In particular, each support base 13.2 is associated with a respective tray cavity 11.1, such that in the absence of cooperation between the support rods 13.1 and the tray positioner 15, the support bases 13.2 rest on the tray frame 11, in particular housed in the corresponding tray cavity 11.1, within the vacuum chamber 1020, and the support plates 13 move together with the tray frame 11 during displacement of the lower sealing assembly 10 between the resting positions Pr and cooperating positions Pc, but, due to the freedom of relative displacement, there is relative displacement between said support plates 13 and said tray frame 11 when the support rods 13.1 and the plate positioner 15 cooperate with each other.

[0029] The tray frame 11 is configured such that, with the lower sealing assembly 10.1 in the cooperating position Pc, the vacuum chamber 1020 is delimited between said tray frame 11 and the upper sealing assembly 20 (FIG. 3). Thus, the support bases 13.2 of the support plates 13 are inside the vacuum chamber 1020, the plate positioner 15 is outside said vacuum chamber 1020 and the cooperation between said plate positioner 15 and the support rods 13.1 is performed outside the vacuum chamber 1020.

[0030] The lower base 10.1 is configured to be connected to the gas extraction source, and the extraction circuit 14 comprises at least one connection conduit 14.0 arranged between the tray frame 11 and the lower base 10.1 (see FIGS. 4 and 5), to fluidically communicate the vacuum chamber 1020 with the gas extraction source (via the lower base 10.1). Thus, by connecting said tray frame 11 to the extraction circuit 14 through the connection conduits 14.0, when it is required to change the type of tray 300 with which to package the product (for example, changing from flat trays to trays with a given height), the machine 100 makes it possible to replace only the tray frame 11, not being necessary to replace the entire lower sealing assembly 10, obtaining as a result a more versatile machine 100. Furthermore, by not needing to house the plate positioner 15 inside the vacuum chamber 1020, the machine 100 also makes it possible to reduce the material of the lower sealing assembly 11 by dispensing with an airtight box between the tray frame 11 and the lower base 10.1, resulting in a cheaper machine 100, and also, by reducing the size of the vacuum chamber 1020 to a minimum, the extraction circuit 14 requires less time to generate the required vacuum due to the reduction of the volume of air contained in the lower sealing assembly 10, resulting in a faster machine 100.

[0031] The extraction circuit 14 comprises, at the lower base 10.1 of the lower sealing assembly 10, a first base mouth 14.1 for being connected to the gas extraction source, a second base mouth 14.2 on a surface facing the tray frame 11, and a base conduction 14.3 which fluidically communicates the first base mouth 14.1 and the second base mouth 14. Further, the extraction circuit 14 comprises a frame mouth 14.4 in the tray frame 11, which is fluidically communicated with the second base mouth 14.2 via the connection conduit 14.0 arranged between the tray frame 11 and the lower base 10.1, and a frame conduction 14.5 which fluidically communicates the frame mouth 14.4 with the vacuum chamber 1020. The frame conduction 14.5 may be formed by an inner gap of the tray frame 11 itself, for example. The frame mouth 14.4 is in fluidic communication with the vacuum chamber 1020, thus vacuum to be generated over the vacuum chamber 1020 being allowed, and said frame mouth 14.4 is on a lower surface 11.9 of the tray frame 11 which faces the lower base 10.1 of the lower sealing assembly 10.

[0032] In some embodiments (not depicted in the figures), the extraction circuit 14 comprises a single connection conduit 14.0 and preferably all the tray cavities 11.1 are communicated with each other via the frame conduction 14.5. The inner gap of the tray frame 11 is fluidically communicated with the first base cavity 14.1 such that the vacuum chamber 1020 is communicated with the gas extraction source via the tray cavities 11.1, the inner gap of the tray frame 11, the connection conduit 14.0 and the lower base 10.1.

[0033] In other embodiments, the extraction circuit 14 comprises a plurality of connection conduits 14.0 and, a second base mouth 14.2 and a frame mouth 14.4 for each connection conduit 14.0. Each connection conduit 14.0 is connected between a corresponding second base mouth 14.2 and a corresponding frame mouth 14.4. The base conduction 14.3 is configured to fluidically communicate the first base mouth 14.1 with all second base mouths 14.2. In some embodiments the extraction circuit 14 comprises a respective frame conduction 14.5 associated with each connection conduit 14.0. In other embodiments the extraction circuit 14 comprises a frame conduction 14.5 associated with a connection group formed by a plurality of connection conduits 14.0, and said extraction circuit 14 comprises a plurality of connection groups, i.e. in these embodiments the extraction circuit 14 comprises a plurality of frame conduits 14.5 and each of said frame conduits 14.5 is associated with a connection group. And in other embodiments, the extraction circuit 14 comprises a frame conduction 14.5 which is associated to all of the connection conduits 14.0.

[0034] The lower base 10.1 comprises an upper block 10.11 attached to the tray frame 11 (via at least one support 11.4) and comprising an upper surface 10.112 facing the tray frame 11 and an opposing lower surface 10.111, and a lower block 10.12 attached to the elevation mechanism 1000 and comprising an upper surface 10.121 in contact with the lower surface 10.111 of the upper block 10.11. The upper block 10.11 and the lower block 10.12 are joined to each other in a decouplable manner, and the upper surface 10.112 of the upper block 10.11 comprises the second base mouth 14.2. At least one of the blocks 10.11 and 10.12 of the lower base 10.1 comprises a block groove 10.81 in the surface 10.111 or 10.121 facing the other block 10.11 or 10.12, the base conduction 14.3 being formed between said block groove 10.81 and said other block 10.11 or 10.12. This facilitates being able to easily and quickly replace the parts of the lower sealing assembly 10 that are required, when it is necessary to change the typology of trays 300 to be packaged (flat trays or trays with height), the type of packaging (change from second skin or vacuum packaging as performed by the lower sealing assembly 10 thanks to the extraction circuit 14, to modified atmosphere packaging or packaging under atmospheric conditions, for example) and / or the number of trays 300 to be packaged, for example, if more parts of the lower sealing assembly 10 rather than the tray frame 11 are intended to be replaced. This fact allows the lower block 10.12 (which is the one attached to the elevation mechanism 1000 and which is attachable to the air extraction source) and the elevation mechanism 1000 itself to be maintained in any event, thus making the machine 100 compatible with other lower sealing assemblies as well. The replaceable parts of the lower sealing assembly 10 can be removed together.

[0035] In some of these embodiments all tray cavities 11.1 are communicated with each other via the frame conduction 14.5 of the tray frame 11, but in other embodiments this is not necessary since different tray cavities 11.1 can also be accessed via different connection conduits 14.0. The frame conduit 14.5 is formed by at least one inner gap of the tray frame 11 and all tray cavities 11.1 are fluidically communicated with said inner gap. In other embodiments the tray frame 11 may comprise more than one inner gap, each inner gap being fluidically communicated with at least one respective connection conduit 14.0, and all tray cavities 11.1 being fluidically communicated with each other. The use of a plurality of connection conduits 14.0 makes it possible to better homogenise the vacuum and to speed it up.

[0036] In some embodiments, for packaging products P in flat trays 300 the tray frame 11 comprises a fixed frame 11.6 and a floating frame 11.5 which is facing the upper sealing assembly 20 and joined to the fixed frame 11.6 with vertical displacement capability. The floating frame 11.5 is configured to be distanced from the fixed frame 11.6 with the lower sealing assembly 10 in the resting position Pr (see FIG. 2), and to be in contact with the fixed frame 11.6 and to generate with such cooperation the frame conduction 14.5 of the tray frame 11, with the lower sealing assembly 20 in the cooperating position Pc (see FIG. 3).

[0037] As shown in FIG. 4, the floating frame 11.5 comprises a recess 11.50 on its surface facing the fixed frame 11.6, and the fixed frame 11.6 comprises a recess 11.60 on its surface that is facing the floating frame 11.5 and that is facing, at least partially, the recess 11.50 of the floating frame 11.5, the frame conduction 14.5 being generated between said recesses 11.50 and 11.60 when the lower sealing assembly 10 is in the cooperating position Pc. The recess 11.50 of the floating frame 11.5 is communicated with the tray cavities 11.1 below the support bases 13.2. In other embodiments, for packaging products P in trays 300 with height, the tray frame 11 does not comprise any floating frame (see FIGS. 5 and 6).

[0038] In any embodiment of the machine 100, the plate positioner 15 may comprise a platform 15.0 facing the support rods 13.1 of the support plates 13 and arranged between the tray frame 11 and the lower base 10.1 of the lower sealing assembly 10, and at least one positioner rod 15.1 (preferably a plurality of positioner rods 15.1) attached to the platform 15.0, extending from said platform 15.0 and passing through said lower base 10.1. Each tray cavity 11.1 comprises a cavity base 11.11 (or surface) configured to support the corresponding support plate 13.2. With the lower sealing assembly 10 in the resting position Pr, the platform 15.0 is spaced apart from the lower base 10.1 of the lower sealing assembly 10 a platform distance A, the support rods 13.1 are supported on the platform 15.0 and the support bases 13.2 of the support plates 13 are spaced apart from the corresponding cavity base 11.11 a platform distance D, the trays 300 being thus elevated (see FIG. 2). With the lower sealing assembly 10 in the cooperating position Pc, the platform 15.0 is in contact with the lower base 10.1 of the lower sealing assembly 10 (or resting on said lower base 10.1), and the support bases 13.2 of the support plates 13 are resting on the cavity base 11.11, the trays 300 not being elevated (see FIG. 3).

[0039] Preferably all the support rods 13.1 have the same length and all the positioner rods 15.1 have the same length, and these lengths are selected such that the distance (height) travelled by the lower base 10.1 with respect to the plate positioner 15 is greater than the distance travelled by the cavity base 11.11 with to the support base 13.2, during the travel of the lower sealing assembly 10 from the resting position Pr to the cooperating position Pc (i.e., the platform distance A is greater than the plate distance D). This means that during the travel of the lower sealing assembly 10 from the resting position Pr to the cooperating position Pc, the support bases 13.2 rest on the cavity bases 11.11 before the lower base 10.1 contacts the platform 15.0 (see FIG. 7), whereupon the support rods 13.1 are separated from the platform 15.0 (see FIG. 8) and the trays 300 move together with the lower sealing assembly 10 up to the cooperating position Pc.

[0040] The lower sealing assembly 10 is configured to be moved from the resting position Pr to the cooperating position Pc a distance greater than the platform distance A, such that once a distance equal to the platform distance D has been travelled, the support plates 13 move together with said lower sealing assembly 10 up to the cooperating position Pc, the support rods 13.1 being distanced from the platform 15.0, and once a distance greater than the platform distance A has been travelled, the platform 15.0 moves together with said lower sealing assembly 10 up to said lower sealing assembly 10 reaches the cooperating position Pc, the positioner rods 15.1 being distanced from the static structure 100.1.

[0041] With the lower assembly 10 in the resting position Pr, the positioner rod 15.1 is supported on a static structure 100.1 of the machine 100 which is arranged below the lower base 10.1 of the lower assembly 10 and which forms part of a frame 101 of the machine 100. The support rods 13.1 have a length such that they are supported on the platform 15.0 of the plate positioner 15 with the lower sealing assembly 10 in the resting position Pr, causing the trays 300 supported by the support plates 13 to be above the tray frame 11 as described above and to be easily manipulated (to evacuate them from the sealing station 3 once the product P is packaged, and to arrange new trays 300 in the sealing station 3). The support rods 13.1 are vertically distanced from said platform 15.0 with said lower sealing assembly 10 in the cooperating position Pc, to allow the trays 300 to be housed in the tray cavity 11.1 and to allow the packaging of the products P to be carried out correctly.

[0042] The positioner rod 15.1 has a length such that, with the lower sealing assembly 10 in the resting position Pr, the positioner rod 15.1 is supported on the static structure 100.1 and, with said lower sealing assembly 10 in the cooperating position Pc, the platform 15.0 is supported on the lower base 10.1 of the lower sealing assembly 10 and the positioner rod 15.1 is vertically distanced from said static structure 100.1.

Claims

1. A heat-sealing machine for sealing trays with a plastic film and which is configured to produce a vacuum between the trays and the plastic film, the machine comprising:an upper sealing assembly;a lower sealing assembly disposed vertically below and facing the upper sealing assembly and moveable between a resting position in which the lower sealing assembly and the upper sealing assembly are vertically spaced apart, and a cooperating position in which the lower sealing assembly and the upper sealing assembly cooperate with each other to generate a vacuum chamber located between the upper and lower sealing assemblies;a lifting mechanism configured to move the lower sealing assembly between the resting position and the cooperating position; andan extraction circuit that, with the lower sealing assembly in the cooperating position, fluidly communicates a gas extraction source with the vacuum chamber;the lower sealing assembly including:a tray frame having a plurality of tray cavities, each of the plurality of tray cavities being configured to receive one of the trays;a lower base vertically spaced from the tray frame, the lower base including one or more fluid conduits of the extraction circuit that are configured to be fluidly communicated with the gas extraction source, the extraction circuit including at least one connection conduit arranged between the tray frame and lower base to fluidly communicate the vacuum chamber with the gas extraction source;a support plate for each tray cavity, each support plate including a support base configured to support one of the trays;one or more support rods coupled to one or more of the support bases;a plate positioner arranged below the tray frame and configured to cooperate with each support rod to cause, with the lower sealing assembly in the resting position, the trays to be supported on the corresponding support bases above the tray frame; andeach support rod extending from the corresponding support base through the tray frame towards the plate positioner, the tray frame being configured such that the vacuum chamber is delimited between the tray frame and the upper sealing assembly, with the lower sealing assembly in the cooperating position each support base rests on the tray frame and each support base is housed in the corresponding tray cavity within the vacuum chamber.

2. The heat-sealing machine according to claim 1, wherein the one or more fluid conduits of the lower base comprise:a first base mouth for connection to the gas extraction source;a second base mouth on a surface facing the tray frame; anda base conduction that fluidly communicates the first base mouth with the second base mouth.

3. The heat-sealing machine according to claim 2, wherein the extraction circuit comprises:a frame mouth in the tray frame that is fluidly communicated with the second base mouth via the at least one connection conduit; anda frame conduction that fluidly communicates the frame mouth with the vacuum chamber.

4. The heat-sealing machine according to claim 1, wherein the extraction circuit comprises:a first base mouth in the lower base for connection to the gas extraction source;a plurality of second base mouths on a surface of the lower base facing the tray frame;a plurality of frame mouths in the tray frame:a plurality of connection conduits that each fluidly communicates a corresponding one of the second base mouths with a corresponding one of the frame mouths; anda base conduction in the lower base that is configured to fluidly communicate the first base mouth with the plurality of second base mouths,a plurality of frame conductions that is each fluidly communicated with an associated one of the plurality of connection conduits, the plurality of frame conductions fluidly communicating the plurality of frame mouths with the vacuum chamber.

5. The heat-sealing machine according to claim 1, wherein the extraction circuit comprises:a first base mouth in the lower base for connection to the gas extraction source;a plurality of second base mouths on a surface of the lower base facing the tray frame;a plurality of frame mouths in the tray frame:a plurality of connection conduits that each fluidly communicates a corresponding one of the second base mouths with a corresponding one of the frame mouths; anda base conduction in the lower base that is configured to fluidly communicate the first base mouth with the plurality of second base mouths,a plurality of frame conductions that is each fluidly communicated with two or more of the plurality of connection conduits, the plurality of frame conductions fluidly communicating the plurality of frame mouths with the vacuum chamber.

6. The heat-sealing machine according to claim 1, wherein the extraction circuit comprises:a first base mouth in the lower base for connection to the gas extraction source;a plurality of second base mouths on a surface of the lower base facing the tray frame;a plurality of frame mouths in the tray frame:a plurality of connection conduits that each fluidly communicates a corresponding one of the second base mouths with a corresponding one of the frame mouths; anda base conduction in the lower base that is configured to fluidly communicate the first base mouth with the plurality of second base mouths,a frame conduction that fluidly communicated with all of the plurality of connection conduits, the frame conduction fluidly communicating the plurality of frame mouths with the vacuum chamber.

7. The heat-sealing machine according to claim 3, wherein the lower base comprises:an upper block coupled to the tray frame and comprising an upper surface facing the tray frame and lower surface facing away from the tray frame; anda lower block coupled to the elevation mechanism and comprising an upper surface in contact with the lower surface of the upper block, the upper block and the lower block being joined to each other in a decouplable manner, the upper surface of the upper block comprising the second base mouth.

8. The heat-sealing machine according to claim 7, wherein the upper block comprises a block groove in the lower surface facing the lower block, the base conduction (14.3) being located between the block groove and the lower block.

9. The heat-sealing machine according to claim 7, wherein the lower block comprises a block groove in the upper surface facing the upper block, the base conduction (14.3) being located between the block groove and the upper block.

10. The heat-sealing machine according to claim 3, wherein the frame mouth is on a lower surface of the tray frame facing the lower base of the lower sealing assembly.

11. The heat-sealing machine according to claim 3, wherein the frame conduction (14.5) is formed by one or more inner gaps of the tray frame.

12. The heat-sealing machine according to claim 3, wherein the tray frame comprisesa fixed frame anda floating frame facing the upper sealing assembly and joined to the fixed frame with the possibility of vertical displacement, the floating frame being configured, with the lower sealing assembly in the resting position, to be distanced from the fixed frame and, with the lower sealing assembly in the cooperating position, to be in contact with the fixed frame and to generate the frame conduction.

13. The heat-sealing machine according to claim 12, wherein the floating frame comprises a first recess on a surface facing the fixed frame, and the fixed frame comprises a second recess on a surface facing the floating frame and facing, at least partially, the first recess, the frame conduction being generated between the first and second recesses when the lower sealing assembly is in the cooperating position.

14. The heat-sealing machine according to claim 13, wherein the first recess is communicated with the tray cavities below the support bases of the support plates.

15. The heat-sealing machine according to claim 1, wherein the plate positioner comprises:a platform that is configured to cooperate with the one or more support rods,at least one positioner rod coupled to the platform and extending from the platform and traversing the lower base,the tray cavity comprising a cavity base,wherein, with the lower sealing assembly in the resting position, the platform is spaced apart from the lower base of the lower sealing assembly a platform distance (A), and the support bases of the support plates are spaced apart from the cavity base a plate distance (D), and with the lower sealing assembly in the cooperating position, the platform is in contact with the lower base of the lower sealing assembly and the support bases of the support plates are supported on the cavity base, the platform distance (A) being greater than the plate distance (D).

16. The heat-sealing machine according to claim 15, wherein the lower sealing assembly is configured to move from the resting position to the cooperating position a distance greater than the platform distance (A).

17. The heat-sealing machine according to claim 16, wherein, with the lower assembly in the resting position, the positioner rod is supported on a static structure arranged below the lower base and which forms part of a frame of the heat-sealing machine, the one or more support rods comprising a length such that they are supported on the platform of the tray positioner with the lower sealing assembly in the resting position, the trays supported by the support plates being caused to be above the tray frame, and the support rods being vertically distanced from the platform with said lower sealing assembly in the cooperating position.

18. The heat-sealing machine according to claim 17, wherein the positioner rod has a length such that, with the lower sealing assembly in the resting position, the positioner rod is supported on the static structure and, with the lower sealing assembly in the cooperating position, the platform is supported on the lower base of the lower sealing assembly and the positioner rod is vertically distanced from the static structure.

19. The heat-sealing machine according to any of claim 15, wherein the plate positioner comprises a plurality of positioner rods coupled to the platform and extending from the platform and traversing the lower base, the plurality of positioner rods having the same length.

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