ATMOSPHERE

Technical Field

The present invention relates to an apparatus for packaging containers, and in particular for packaging containers for heat sealing with a single- folded film.

More in particular, the invention relates to a manual bell shrink wrapping packaging machine in a protective atmosphere for packaging starting from single-folded film.

Background art

Currently, there are known bell shrink wrapping packaging machines which allow packaging to be carried out starting from a single-folded film, which however do not allow operating in a protective atmosphere. Packaging machines are also known which allow packaging in a protective atmosphere but are limited to the use of a flat-type unfolded film and do not include the shrink wrapping of the film.

Furthermore, semi-automatic apparatuses are known which make use of single-folded films for packaging in a controlled atmosphere, but which are not capable of shrinkwrapping the film

Therefore, there is the need for a manual bell packaging machine which is able to perform the packaging of objects in a controlled atmosphere, for example containers of foodstuffs, starting from single-folded film, and to perform a shrink wrapping step of the film inside the same bell.

Object of the Invention

The present invention is therefore intended to overcome the drawbacks of the already known solutions and to provide a manual packaging machine equipped with a packaging chamber inside which are performed the sealing steps of a single-folded film, of packaging an object inside the film in a controlled atmosphere and of shrink wrapping the single-folded film around the packaged object. Summary of the invention

These objects have been achieved by realising a packaging machine according to at least one of the appended claims.

A first advantage is that the machine obtained, although of a manual type and with a relatively limited footprint, is able to carry out different packaging steps in the same footprint and therefore to offer a high packaging quality even to users which do not need to work on large numbers of packages.

A second advantage consists in reducing the amount of gas introduced by the nozzle and used to create the controlled atmosphere List of Drawings

These and other advantages will be better understood by anyone skilled in the art from the description below and the accompanying drawings, given as a non-limiting example, in which: - fig. 1 shows a machine according to the invention in perspective view;

- figs. 2a-2b respectively show a machine according to the invention in an open bell configuration waiting to receive a product to be packaged and in an open bell configuration with the product to be packaged therein;

- fig. 3 shows the machine of fig. 1 in a closed bell configuration and the product to be packaged therein;

- fig. 4 shows a detail of the film sealing;

- fig. 5 shows a perspective view of the machine shown in fig. 1 in an open bell configuration and with the product to be packaged therein;

- fig. 6 shows the side view from the right of the machine of fig. 3-4 in a closed bell configuration and with the product to be packaged therein;

- fig. 7 shows a detail of the movement of the sealing bars in a machine according to the invention and a detail of a possible example of the air circulation in the bell of a packaging machine according to the invention;

- fig. 8 shows a machine according to the invention in a top view. Detailed Description With reference to the accompanying drawings, a packaging machine 1 for packaging objects V starting from a single-folded shrink wrappable film F is described.

The machine comprises a hermetically sealed packaging chamber 2 composed of a first and a second section 3, 4 movable with respect to each other and preferably articulated to each other by means of a hinge 15, for example, so as to allow a manual operation by a handle 9 graspable by an operator to hermetically close the two sections of the chamber 2.

In a preferred embodiment, the fixed and movable sections 3, 4 of the chamber 2 are retained in the hermetically sealed position by special retaining means, for example electromagnets 13 associated with said first and second sections and activatable on command.

Inside the chamber 2 are included first and second sealing means 5, 6, consisting, for example, of movable sealing bars 5, concealed in the lower fixed section 3 of the chamber 2 and counterbars 6 fixed to the upper movable section 4, respectively.

The bars and counterbars 5, 6 are arranged to seal the flaps L of the film F in a longitudinal advancement direction of the film and in a transverse direction, in hermetically sealed conditions of the chamber 2.

Preferably, the sealing step occurs by pushing means 12, for example pistons operable on command to push the movable sealing bars 5 against the sealing counterbars 6 and perform the sealing of the film flaps comprised between bars and counterbars.

The machine further comprises atmospheric conditioning means to create a controlled atmosphere inside the chamber 2 when it is in closed conditions.

The conditioning means preferably comprise a vacuum pump 10 for creating a vacuum in the chamber 2 controlled by suitable vacuum sensors and a nozzle 11 connected to a gas source 20, for introducing a controlled amount of gas inside the film F arranged around the object V to be packaged.

Advantageously, the nozzle 11 is arranged transversely to the film F and is adjustable in length, for example by being telescopic, in order to be adaptable to different widths of the film.

Furthermore, the arrangement of the transverse nozzle in full width has the advantage of allowing a correct positioning of the film and avoiding unwanted folds during the unwinding thereof

The machine 1 further comprises shrink wrapping means 8 for bringing the temperature of the chamber to a value greater than a shrink wrapping value of the film F, in order to cause the shrink wrapping of the single- folded film around the object V to be packaged.

Preferably, the shrink wrapping means comprise a fan 8, for example helical or tangential, to circulate for an appropriate time a hot air flow inside the chamber 2 and around the product V wrapped by the sealed single-folded film F.

By way of example, the hot air can be obtained by means of resistors 14 crossed by the air flow created by the fan 8 and circulating in the chamber 2 due to the push of the fan.

In the operation of the machine, the operator places the product V inside the single-folded film preferably extracted from a reel 18 on a loading plane 16 outside the chamber 2.

In this step, the film F has the flaps of the front transverse side, i.e., the flaps away from the reel 18, already sealed during the previous packaging. Subsequently, the operator places the product with the film on a support surface 22 inside the chamber 2, for example by unwinding the reel manually.

After positioning the product, the operator manually closes the chamber by acting on the handle 9 to rotate the upper movable section 3 on the hinge 15 which, once superimposed on the lower section 3, is held in place by some electromagnets, preferably three electromagnets 13 which can be activated in the closing condition of the chamber 2.

As soon as the chamber is closed and the electromagnets are activated, the vacuum pump 10 is activated creating a vacuum inside the chamber 2. Preferably, by way of example, the vacuum obtained is about 0.02 atm. When the desired vacuum is reached, a valve 23 isolates the chamber and the vacuum pump 10 turns off. Subsequently, by means of the nozzle 11 connected to a gas source 20, the gas is introduced inside the film (fig. 9) and therefore not inside the entire volume of the chamber. Advantageously, the nozzle is adjustable in length, for example telescopically, to allow the use of reels with different widths, and supports 19 of the film may be provided to prevent it from accidentally coming into contact with the sealing bars.

After a certain period of time introducing gas, the movable sealing bars 5 located in the lower section of the chamber are pushed by the pistons 12 of the lower section against the counterbars 6 mounted in the upper movable section of the chamber.

In this step, the force exerted on the upper section by the pistons is counterbalanced by the force of attraction of the electromagnets which ensure the closing seal of the chamber 2.

After sealing, the pistons retract, moving the sealing bar 5 away from the film, to avoid unwanted shrink wrapping phenomena.

In this step, when the sealing is complete, a valve is opened which allows air to enter the chamber 2, recreating a situation of balance between external and internal pressure in the chamber.

To perform the next shrink wrapping step, the air entering the chamber 2 is directed and forced to pass in contact with the resistors 14 so that the hot air flow, exiting the resistor, follows the bell-shaped geometry of the chamber 2 so as to uniformly surround the product.

As soon as the balance has been reached, the fan 8 is activated for a certain period of time in order to convey the air inside the resistor 14 and move the air inside the chamber. Once the time for wrapping the film has elapsed, the fan and the resistor turn off and the tension in the electromagnets is inverted to automatically open the bell which, possibly assisted by an air piston, allows a “weightless” opening of the upper section 4 and the extraction of the packaged product V from the chamber 2.

The present invention has been described according to preferred embodiments, but equivalent variants can be conceived without departing from the scope of protection granted.