Valve for containers adapted to under-vacuum packaging of products, container provided with said valve and adapted to under-vacuum packaging of products

Abstract

 A container (2) for under-vacuum packaging of products comprises an envelope (3) for housing a product. The envelope (3) is inserted in the container (2) through an access opening (5) provided with an airtight sealing hinge (6) having opposite closing portions (7, 8) identical with each other in their structure. The container (2) also comprises a valve (1) consisting of a base body (9) that, in the envelope (3), defines a sucking duct (10), a closing element (11) capable of hermetically sealing the sucking duct (10), and a locking element (12) designed to lock the closing element (11) to the closed position. The locking element (12) is maintained always linked to the base body (9) by means of appropriate abutment elements (14, 15).

Description

[0001] The present invention relates to a valve for containers adapted to under-vacuum packaging of products and to a container or bag for under-vacuum packaging of products provided with such a valve.

[0002] In detail, the present invention is particularly used in the storage field for packaging any type of products requiring to remain in a substantially under-vacuum environment. The present invention therefore can be used both with reference to conservation of particular types of food, and as regards holding of any other product or article to be packaged, such as the linen of a house the great bulkiness of which is greatly reduced due to the difference of volume between the article under use conditions and the same article from which air has been drawn (see quilts, bathrobes and the like, for example).

[0003] It is known that said containers or bags for packaging goods under vacuum normally have a holding envelope defining a respective housing space provided with an access opening for introduction and extraction of one or more products. At the access opening, these containers are usually provided with appropriate sealing means capable of hermetically isolating the housing space from the surrounding atmosphere. In order to enable the air present in the housing space to be sucked while at the same time ensuring an airtight sealing of same, these containers are further provided with a suction valve exclusively set to allow one-way flowing of the air, from the housing space to the surrounding atmosphere.

[0004] In particular, the above mentioned valves comprise a base body to be engaged with the envelope of the respective container and defining an air-sucking duct therein. Operatively engaged at the sucking duct is a closing element that, following suction of the air present in the container, allows transit of said air from the container to the outside and, when suction is stopped, obstructs the passage channel avoiding the air going back into the housing space.

[0005] One type of known suction valves (among the great number presently on the market) further comprises an auxiliary body associable with the base body by restrained fitting. The auxiliary body better defines the air-sucking duct in which the closing element operates, said element being therefore confined between the base body and said auxiliary body. On the opposite side with respect to the base body and at the sucking duct, the auxiliary body further has a substantially cylindrical attachment flange, to be engaged by interference with a respective closing plug that is set to close the end of the passage channel opposite to the base body.

[0006] Before carrying out suction of the air through the suction valve, the access opening of the container or bag is sealed by the above mentioned closing means that usually consists of an appropriate closing hinge. The closing hinge is currently made up of two closing portions different in structure and internally fastened to opposite walls of the container, so that, following engagement of a closing portion onto the other, they fit into each other in a permanent manner.

[0007] Each closing portion of known hinges, as usual, is generally provided with seats and snap-fitting protrusions susceptible of mutual cooperation. Normally, the number of the seats and fitting protrusions is greater on one of the two closing portions so as to supply a wide engagement region for the other closing portion.

[0008] While known containers or bags for under-vacuum packaging of products allow satisfactory holding of the same, they however have some drawbacks, mainly in relation to maintenance of airtightness in the containers themselves, and conservation of the product contained therein.

[0009] More specifically, the structure of the suction valves does not ensure an optimal isolation of the housing space from the surrounding atmosphere. In fact, these containers can be submitted to possible air seepage usually taking place as a result of malfunction of the sealing system partly made up of the valve itself. In detail, the closing element present in the sucking duct of each valve keeps the housing space of said container hermetically isolated from the surrounding atmosphere, through the thrust action taking place on the closing element following the vacuum present in the container. In other words, the closing element is capable of obstructing the sucking duct only in the presence of a great pressure difference between the housing space of the respective container and the surrounding atmosphere, which difference keeps the closing element pressed against the base body blocking the sucking duct end facing the container. Obviously, the longer the storage time of the contained product is, the more the closing element is likely to allow the outer air to penetrate into the housing space thus re-establishing the original conditions.

[0010] Still with reference to airtightness of these containers, the presence of closing hinges consisting of closing portions different in structure from each other increases the likelihood that air seepages may occur. In detail, this drawback is due to the fact that, since these closing portions are of different structure, they are made by distinct machinery and extrusion dies which are clearly submitted to different environmental factors, such as humidity, temperature and so on. These factors affect the sizes of the obtained closing portions in a different manner and have a different incidence on the airtightness of the hinges they form.

[0011] In addition, it will be recognised that use of two extrusion dies for making the closing hinges concurrently with the presence of suction valves made up of many structural elements gives rise to high production costs for the container, which costs directly affect the selling prises of the latter.

[0012] The main aim of the present invention is to ensure an optimal airtightness of the containers for under-vacuum packaging of products by arranging a suction valve and a closing hinge that are reliable in terms of airtight sealing and consequently in terms of conservation of the products contained therein.

[0013] It is a further aim of the invention to provide containers for under-vacuum packaging of products that are capable of maintaining their vacuum state unchanged in time thereby allowing elimination of periodic inspections or controls for ascertaining the container conditions.

[0014] Another aim of the invention is to greatly reduce the container costs by intervening both on the number of components forming the suction valves and on the number of the extrusion dies required for manufacturing the closing hinges.

[0015] The foregoing and further aims that will become more apparent in the course of the following description are substantially achieved by a valve, in particular for containers adapted to under-vacuum packaging of products, and by a container or a bag for under-vacuum packaging of products, which have the features set out in the claims.

[0016] Further features and advantages will become more apparent from the detailed description of a preferred, but not exclusive, embodiment of a valve for containers adapted to under-vacuum packaging of products, and of a container or a bag for under-vacuum packaging of said products, in accordance with the present invention. This description will be taken hereinafter with reference to the accompanying figures given by way of non-limiting example, in which:

• Fig. 1 is an exploded perspective view of a valve, in particular for containers adapted to under-vacuum packaging of products, in accordance with the present invention;
• Fig. 2 is a section of the valve seen in the preceding figure in an open condition and taken along line X-X in Fig. 1;
• Fig. 3 is a section of the valve seen in the preceding figures in a closed condition and taken along line X-X in Fig. 1;
• Fig. 4 is a perspective view of a container for under-vacuum packaging of products, provided with the valve shown in the preceding figures;
• Fig. 5 is a cross-section of a closing hinge of the container shown in Fig. 4.

[0017] With reference to the drawings, a valve, in particular for under-vacuum packaging of products, in accordance with the present invention has been generally identified by reference numeral 1.

[0018] As shown in the drawings and in particular in Fig. 4, valve 1 is in engagement with a container 2 comprising a holding envelope 3. The holding envelope 3 is preferably made of a deformable and impermeable material such as a plastic material. The holding casing 3 defines a housing space 4 capable of receiving one or more products (not shown) to be packaged. This holding envelope 3 is further provided with at least one access opening 5 for introduction and/or extraction of the concerned products. The access opening 5 is set to be hermetically closed to allow isolation of the housing space 4 from the surrounding atmosphere when suction of the air present in container 2 is required, which operation is carried out by suitable suction means (not shown as known by itself) to be operatively engaged with valve 1.

[0019] To ensure an airtight isolation of the housing space 4 and the product contained therein from the surrounding atmosphere, container 2 comprises at least one closing hinge 6 operating close to the access opening 5. As shown in Fig. 5, the closing hinge 6 comprises a first and a second closing portions 7, 8 internally engaged with container 2, on opposite walls 2a, 2b of the latter.

[0020] In detail, each closing portion 7, 8 extends on the respective wall 2a, 2b over the whole transverse extension, and comprises at least one support structure 7a, 8a for engagement with a corresponding wall 2a, 2b of container 2. The support structure 7a, 8a of each closing portion 7, 8 preferably has a substantially flattened shape facilitating engagement of same, for example by a heat-sealing operation, with the respective wall 2a, 2b of container 2.

[0021] Each closing portion 7, 8 further comprises at least one fitting structure 7b, 8b integral with the respective support structure 7a, 8a and facing the opposite closing portion 7, 8, so that it may possibly interact with a respective fitting structure 7b, 8b of the latter to ensure a hermetic closure of the access opening 5.

[0022] The fitting structure 7b, 8b of each closing portion 7, 8 has at least one fitting seat 7c, 8c extending over the whole extension of the closing portion and at least one fitting protrusion 7d, 8d jutting out of the fitting structure 7b, 8b and also extending substantially over the same length as that of the fitting seat 7c, 8c.

[0023] According to the embodiment shown in Fig. 5, it is preferred to have the closing portions 7, 8 of the closing hinge 6 identical with each other in structure so that they can be manufactured by the same extrusion die or similar machine.

[0024] Preferably, each closing portion 7, 8 has two fitting seats 7c, 8c that are substantially parallel to each other and three fitting protrusions 7d, 8d that are substantially parallel and alternated with the fitting seats. More specifically, each fitting seat 7c, 8c seen in cross-section has a substantially rounded outline of a substantially circular extension the width of which progressively narrows away from the respective support structure 7a, 8a. Likewise, the fitting protrusions 7d, 8d too seen in cross-section have a substantially rounded outline of a substantially circular extension, narrowing close to the support structure 7a, 8a. In other words, the shape of the fitting seats 7c, 8d matches that of the fitting protrusions 7d, 8d to ensure a perfect fitting of the closing portions 7, 8 of said closing hinge 6.

[0025] As shown in Figs. 1 to 3, the above mentioned valve 1 comprises a base body 9 to be hermetically engaged with the envelope 3 of container 2 and defining, in said container, at least one sucking duct 10 of the air present therein.

[0026] Valve 1 further comprises at least one closing element 11 operatively associated with the base element 9 to act at the sucking duct 10. The closing element 11 is movable between an open position (Fig. 2) at which suction of the air present within container 2 is allowed through the sucking duct 10, and a closed position (Fig. 3), at which the sucking duct 10 is obstructed by the closing element itself.

[0027] Still with reference to Figs. 1 to 3, valve 1 further comprises at least one locking element 12 operatively in engagement with the base body 9 and movable between a first position (Fig. 2) at which the closing element 11 is free to remain in the open position and/or in the closed position, and a second position (Fig. 3) at which the locking element 12 is active on the closing element 11 to keep the latter to the closed position.

[0028] In more detail, the locking element 12 ensures hermetic seal of the sucking duct 10 by the closing element 11 when the locking element is in the second position.

[0029] The above mentioned base body 9 of valve 1 is susceptible of engagement with the envelope 3 of the respective container 2 by means of at least one substantially flat adhesion portion 9a that is directly welded, preferably by at least one heat-sealing operation, internally of a wall 2a, 2b of the container itself.

[0030] In order to facilitate engagement of valve 1 with the envelope 3 of the respective container 2, the adhesion portion 9a of the base body 9 has, at the area destined to welding, one or more surface projections 9b substantially extending parallel to each other. As shown in Fig. 1, the base body 9 has two (or even more) surface projections 9b of circular extension and concentric with each other.

[0031] In addition, the base body 9 is preferably of a plate-like shape with a substantially disc-shaped conformation so that the adhesion portion 9a corresponds to one of the two surfaces of the base body facing the locking element 12.

[0032] Valve 1 further comprises permanent coupling means 13 operatively interposed between the base body 9 and locking element 12 to maintain the latter linked to the base body 9 both in the first and in the second positions.

[0033] In detail, the permanent coupling means 13 comprises a first abutment element 14 associated with the locking element 12 and a second abutment element 15 associated with the base body 9, said elements interacting with each other to keep the locking element 12 linked to the base body 9. The first abutment element 14 is defined by a first thread 16 formed in a substantially cylindrical coupling portion 17 of the locking element 12. In more detail, the first thread 16 extends in a helical extension on an inner cylindrical surface 17a of the coupling portion 17 of the locking element 12. The second abutment element 1.5 on the contrary is defined by at least one abutment edge 15a jutting out of a free end of a substantially cylindrical coupling portion 18 of the base body 9. As shown in Figs. 1 to 3, the second abutment element 15 projects from an outer cylindrical surface 18a of the coupling portion 18 of the base body 9, substantially in a direction perpendicular to the extension of the coupling portion itself defining at least one abutment surface 15b facing the base body 9 and adapted to directly interact with the first abutment element 14.

[0034] The permanent coupling means 13 further contemplates the presence of a second thread 19 formed in the coupling portion 18 of the base body 9 and cooperating with the first thread 16 to ensure displacement of the locking element 12 between the first and second positions. In detail, the second thread 16 is formed in the outer cylindrical surface 18a of the coupling portion 18 of the base portion 9, between the latter and the second abutment element 15.

[0035] Still with reference to Figs. 1 to 3, the locking element 12 has a substantially cylindrical locking portion 20 which is concentric with the coupling portions 17, 18 of the locking element 12 and the base body 9, respectively. The locking portion 20 has an outer diametrical size that does not exceed the inner diametrical size of the coupling portion 18 of the base body 9. Preferably, the outer diametrical size of the locking portion 20 is substantially the same as the inner diametrical size of the coupling portion 19 of the base body 9 so that the locking portion 20 adheres at least partly to an inner cylindrical surface 18b of the coupling portion 18.

[0036] The locking portion 20 further has a substantially horizontal engagement surface 20a facing the base body 9 and active on the closing element 11 (Fig. 3) when the locking element 12 is in the second position.

[0037] In addition, the section of the locking portion 20 narrows close to the engagement surface 20a to define a lead-in region for engagement of the locking portion itself within the coupling portion 18 of the base body 9.

[0038] On the opposite side with respect to the inner cylindrical surface 17a of the coupling portion 17 of the locking element 12, said coupling portion 17 has an outer cylindrical surface 17b provided with a plurality of surface projections 12a for carrying out manual displacement of the locking element 12 between the first and second positions. In other words, the surface projections 12a supply a grip point for manual rotation of the locking element 12 when displacement of the latter is required.

[0039] As shown in Fig. 2, the sucking duct 10 of valve 1 is at least partly defined by the coupling portion 18 of the base body 9 and the locking portion 20 of the locking element 12 constituting a passage chamber 21 for the air in transit. The passage chamber 21 is in fluid communication with the housing space 4 of container 2 through at least one suction opening 22, formed through the base body 9 in a concenctric manner with the coupling portion 18 of the latter and the coupling portion 17 of the locking element 12, so that it is confined within the coupling portion 17 of the base body itself.

[0040] The passage chamber 21 further has at least one vent 23 formed through the coupling portion 18 of the base body 9 through which suction of the air present in container 2 is carried out.

[0041] In detail, the sucking duct 10 is provided with two vents 23 formed through the coupling portion 18 of the base body 9 at diametrically opposite sides. As shown in Fig. 1, preferably each vent 23 extends between the base body 9 and the free end of the coupling portion 18 of the latter without a break so as to constitute respective interruption regions of the coupling portion itself thereby defining two substantially semi-cylindrical coupling half-portions 18c, 18d.

[0042] Advantageously, this configuration gives the coupling portion 18 a light flexibility along a direction substantially perpendicular to the longitudinal axis of same so that assembling and/or disassembling of valve 1 is made easier by the possibility of moving the two coupling half-portions 18c, 18d close to each other and bending them to engage and/or disengage the locking element 12.

[0043] Still with reference to Figs. 1 to 3, valve 1 comprises one or more diametrical baffles 24 located at the suction opening 22 to supply the closing element 11 with a support, preferably in the presence of a vacuum within container 2. More specifically, the diametrical baffles 24 prevent the closing element 11 from partly deforming and taking an abnormal position capable of impairing the container airtightness, due to the high pressure difference between the outside environment and the housing space 4 of container 2.

[0044] Therefore, the closing element 11 which comprises a substantially plate-like and preferably disc-shaped seal made of an elastically deformable material may partly bear on the above mentioned diametrical baffles 24 crossing each other at the centre of the suction opening 22.

[0045] Since the closing element 11 must operate within the coupling portion 18 of the base body 9, it has a diametrical size that does not exceed the inner diametrical size of said coupling portion. Preferably, the diametrical size of the closing element 11 is in any case bigger than the transverse sizes of the suction opening 22 in order to ensure, on the one hand, complete closing of said suction opening and, on the other hand, a further support along a peripheral edge of said suction opening 22.

[0046] As shown in Figs. 2 and 3, valve 1 further comprises at least one substantially cage-shaped portion 25 in engagement with the base body 9 at the suction opening 22 and on the opposite side with respect to the coupling portion 18 of the base body itself. The cage portion 25 protects the suction opening 22 and consequently the sucking duct 10 against the possibility that the contained product may approach the suction opening itself. Both the base body 9 and the locking element 12 of valve 1 are preferably made of plastic material, whereas the closing element is preferably made of rubber.

[0047] In addition, valve 1 in accordance with the present invention is exclusively made up of three components as already widely described, i.e. the base body 9, closing element 11 and locking element 12.

[0048] When it is necessary for a product to be packaged under vacuum, said product is inserted in the housing space 4 of said container 2 through the access opening 5 thereof. The access opening 5 is hermetically sealed bringing the closing portions 7, 8 of the closing hinge 6 substantially against each other and pressing them. Under this situation, the fitting protrusions 7d, 8d slightly open out the fitting seats 7c, 8c of the opposite fitting portion 7, 8 and become snap fitted thereinto to form a sealed block.

[0049] After closure of the access opening 5, the air present in container 2 is sucked by the above mentioned suction means that is temporarily engaged with valve 1 externally of container 2.

[0050] Obviously, to enable air suction the locking element 12 must be placed to the second position (Fig. 2) or at least to an intermediate position between the first and second positions to allow passage of air.

[0051] During suction, the air present in container 2 flows through the cage portion 25 and the suction opening 10, as shown by arrow "F" in Fig. 2, invading the passage chamber 21 and then going out of the latter through vent 23. At the passage chamber 21 the flowing air licks the closing element 11 that is therefore partly deformed due to the forces therein present.

[0052] Once the air has been sucked, the suction means is disengaged from valve 1. The closing element 11 is consequently maintained to the closed position by the atmospheric pressure, i.e. against the base body 9 and it closes the suction opening 10 of said base body.

[0053] At this point, by manually acting on the locking element 12, the latter can be screwed down until it takes the first position so that it acts by its locking portion 20 on the closing element 11 that is firmly blocked to the closed position.

[0054] After extraction of the product contained therein, a new packaging of another product can be carried out by bringing the locking element 12 back to the second position to use the suction means again.

[0055] Advantageously, due to the presence of the abutment elements 14, 15, the locking element 12 is secured to the base body 9, which will avoid an undesirable disengagement and loss of the latter and of the closing element 11.

[0056] The present invention solves the problems found in the known art and achieves the aimed purposes.

[0057] The presence of a valve provided with a locking element capable of fixing the closed position of the closing element 11 ensures an'excellent airtightness of container 2 with which it is associated because the vacuum condition is maintained in time by a purely mechanical closing system.

[0058] In addition, it will be recognised that the presence of a closing hinge 6, the closing portions 7, 8 of which are made using the same extrusion die, ensures an excellent airtight sealing, as regards closure of the access opening 5 of container 2. This advantage is obtained by eliminating size differences between one closing portion 7, 8 and the other, usually due to different physical factors to which the different extrusion dies for making said closing portions are subjected. In fact manufacture of structurally identical closing portions 7, 8 allows the same to be formed by a single extrusion die avoiding the problem of size differences.

[0059] Finally, due to the presence of a limited number of components forming valve 1 (that in the present case are exclusively three) and to use of a single extrusion die, there is a great reduction in the production costs and in the selling or market prices of the containers for under-vacuum packaging of products.

Claims

1. A valve, in particular for containers (2) adapted to under-vacuum packaging of products, said valve (1) comprising:

- a base body (9) to be sealingly engaged with one of said containers (2) and defining at least one air-sucking duct (10) within the container itself;

- at least one closing element (11) operatively associated with the base body (9) to act at the sucking duct (10), said closing element (11) being movable between an open position at which suction of the air present within the container (2) is allowed and a closed position at which the sucking duct (10) is obstructed by said closing element (11),

characterized in that it further comprises at least one locking element (12) operatively in engagement with the base body (9) and movable between a first position at which the closing element (11) is free to remain either in the open position or in the closed position, and a second position at which the' locking element (12) is active on said closing element (11) to maintain the latter in the closed position, the locking element (12) ensuring airtight sealing of the sucking duct (10) by the closing element (11) when the latter is in the second position.

2. A valve as claimed in claim 1, characterized in that it comprises permanent coupling means (13) operatively interposed between said base body (9) and said locking element (12) to keep the latter linked to said base body (9) both in the first and in the second positions.

3. A valve as claimed in claim 2, characterized in that said coupling means (13) comprises:

- a first abutment element (14) associated with said locking element (12);

- a second abutment element (15) associated with said base body (9), said first and second abutment elements (14, 15) interacting with each other, when the locking element (12) is situated in the second position, to ensure engagement of the latter with the base body (9) in the second position.

4. A valve as claimed in claim 3, characterized in that said first abutment element (14) is substantially defined by a first thread (16) formed in a coupling portion (17) of the locking element (12).

5. A valve as claimed in claim 4, characterized in that the coupling means (13) further comprises a second thread (19) formed in a respective coupling portion (18) of the base body (9), the first and second treads (16, 19) being set to cooperate to ensure displacement of the locking element (12) between the first and second positions.

6. A valve as claimed in claim 5, characterized in that the second abutment element (15) is defined by at least one abutment edge (15a) jutting out of a free end of the respective coupling portion (18), in a direction substantially perpendicular to the extension of the latter.

7. A valve as claimed in claim 6, characterised in that the second thread (19) is formed in the coupling portion (18) of the base body (9) between the latter and the second abutment element (15).

8. A valve as claimed in one or more of claims 5 to 7, characterized in that the first thread (16) of the coupling portion (17) of the locking element (12) is formed in an inner cylindrical surface (17a) of the coupling portion (17) of the locking element (12) and the second thread (19) of the coupling portion (18) of the base body (9) is formed in an outer cylindrical surface (18a) of the coupling portion (18) of the base body (9).

9. A valve as claimed in claim 8, characterized in that the locking element (12)' has a substantially cylindrical locking portion (20) which is concentric with the coupling portions (17, 18) of the locking element (12) and the base body (9), the locking portion (20) having an outer diametrical size that does not exceed the inner diametrical size of the coupling portion (18) of the base body (9).

10. A valve as claimed in claim 9, characterized in that the locking portion (20) of the locking element (12) has an outer diametrical size that is substantially the same as the inner diametrical size of the coupling portion (18) of the base body (9), so that the locking portion (20) adheres at least partly to an inner cylindrical surface (18c) of the coupling portion and has an engagement surface (20a) facing the base body (9) and active on the closing element (11) when the locking element (12) is in the second position.

11. A valve as claimed in one or more of claims 1 to 10, characterized in that the base body (9) has at least one portion (9a) adhering to the container (2) that is substantially flat to facilitate a steady engagement between the valve (1) and the container itself.

12. A valve as claimed in claim 11, characterized in that the base body (9) on said adhesion portion (9a) has one or more surface projections (9b) extending substantially parallel to each other.

13. A valve as claimed in one or more of claims 1 to 12, characterized in that it further has at least one suction opening (22) formed through the base body (9) and at least partly defining said sucking duct (10).

14. A valve as claimed in claim 13 when dependent on one or more of claims 5 to 12, characterised in that the sucking duct (10) is further defined:

- by the coupling portion (18) of the base body (9);

- by the locking portion (20) of the locking element (12); said locking portion (20), coupling portion (18) of the base body (9) and suction opening (22) being substantially concentric;

- by at least one vent (23) formed through the coupling portion (18) of the base body (9).

15. A valve as claimed in claim 14 and in one or more of claims 5 to 12, characterised in that the sucking duct (10) has two vents (23) formed through the coupling portion (18) of the base body (9) on diametrically opposite sides, the vents (20) extending between the base body (9) and the free end of the coupling portion (18) of the latter without a break, in such a manner as to constitute respective interruption regions of the coupling portion itself and thereby defining two substantially semi-cylindrical coupling half-portions (18c, 18d).

16. A valve as claimed in one or more of claims 13 to 15, characterized in that it comprises one or more diametrical baffles (24) placed at the suction opening (22) to supply said closing element (11) with a support preferably in the presence of a vacuum within the container (2) that gives rise to an adhesion of the closing element (11) against the suction opening (22).

17. A valve as claimed in one or more of claims 13 to 16, characterized in that it further comprises a substantially cage-shaped portion (25) in engagement with the base body (9) at the suction opening (22) and on the opposite side with respect to the coupling portion (18) of said base body, the cage portion (25) protecting the suction opening (22) and therefore the sucking duct (10) against the possibility that the product housed within the container (2) may approach the suction opening itself.

18. A valve as claimed in claims 9 to 17, characterised in that the closing element (11) has a diametrical size that does not exceed the inner diametrical size of the coupling portion (18) of the base body (9), so that the closing element (11) is housed within said coupling portion (18) between the base body (9) and locking element (12).

19. A valve as claimed in one or more of claims 11 to 18, characterised in that the valve can be hermetically associated with said container (2) by heat-sealing, which operation is carried out at a container area superposed on said adhesion portion (9a) of the base body (9).

20. A container for under-vacuum packaging of products comprising a holding envelope (3) provided with at least one access opening (5) for insertion and/or extraction of at least one respective product, said access opening (5) being set to be hermetically closed to isolate the inside of the container (2) from the surrounding atmosphere, characterised in that it further comprises at least one air- sucking valve (1) to draw out of the container (2) the air present therein, and has the features set out in one or more of claims 1 to 19.

Drawing