Method of and apparatus for removing oxygen from upper portion of a packaging container

The subject of the invention is a method and device for removing oxygen from the top of aseptically filled packaging, in which the packaging is filled in sterile air, then sterile nitrogen is injected using a nozzle located exactly above the opening in the packaging, at room temperature and atmospheric pressure, to sterile air and the packaging is sealed between two sealing elements.

In the field of aseptic filling with the help of certain types of equipment it is not possible to fill the package and seal it without leaving a small volume of gas, called the upper part. Since the systems are usually used in sterile air, this upper part contains about 20% oxygen. The presence of oxygen has a negative effect in the sense that during storage of the product contained in said packaging it often happens that the product is sensitive to oxygen, which leads to degradation of its taste and / or certain ingredients such as vitamins and mineral salts. This phenomenon is unacceptable to the consumer or when stating food. One solution sought to reduce the top has already been realized: in this case, just before sealing, the air is replaced with steam. However, the disadvantage of this is that the steam condenses on cold surfaces: the consequence is the unacceptable risk of contamination of neutral or slightly acidic products. The second solution consists in reducing the upper part by means of mechanical elements pressing on the packaging, but it is not possible to completely remove said upper part. Patent DE 3 108 817 also relates to a device for removing oxygen from the top of the packaging. In this device, the nitrogen injection nozzle is attached to one of the sealing elements, thereby reducing the nitrogen supply efficiency, because said nozzle moves and the nitrogen flow changes direction. US 4,934,127 and EP 479 037 also relate to devices for removing oxygen from the top of a package. The disadvantage of these devices is that the packaging is sealed behind the nitrogen injection station, as a result of which a certain amount of previously introduced nitrogen can be distributed.

The object of the present invention is to achieve a method that allows oxygen to be removed efficiently from the top of aseptically filled packaging. By removal is meant to obtain a very low oxygen content in the upper part, i.e. about 2% or less.

According to the method of the invention, sterile nitrogen is injected from a nozzle, which is placed and secured between two movable sealing elements.

The packaging used may be of any type, provided that the top can be sealed.

The packaging filling product may be any type of food liquid, for example based on milk, fruit juice or water, and may further include a separate piece component. In particular, oxygen-sensitive and slightly acidic products, such as diet products containing vitamins and mineral salts, are preferred. The goal is to obtain a product having a long shelf life, in which there is no degradation of taste and / or certain ingredients during storage.

The method is carried out on a conventional industrial production line, which in particular has a filling and sealing compartment, according to the invention it is necessary to add a nitrogen injection step in the sealing compartment.

Two compartments, filling and sealing, are subjected to a sterile air stream to create turbulence in them: the rate of nitrogen injection is faster than the rate of sterile air injection. To obtain an upper part with an oxygen content of less than 2%, it is necessary to work at a nitrogen flow rate on the line between 100 and 800 l / min at atmospheric pressure.

The duration of nitrogen injection for one package is about one second. This fast nitrogen injection saves some nitrogen and reduces the length of the production line. Operation with continuous nitrogen supply as well as with discontinuous nitrogen supply is possible.

The efficiency of removing the remaining air from the upper part is improved by means of a special nitrogen flow system: in this case, nitrogen is supplied at an angle between 40 and 50 ° from the vertical and with the flow meter in the direction of packaging movement.

The invention furthermore relates to a device that can be used to implement the method described above. The device comprises a compartment for filling the package with the product, a compartment for sealing said package by means of two sealing elements and a transport device for transferring the packages to two compartments, the second compartment comprising a fixed nitrogen injection nozzle which is positioned between the movable sealing elements.

A conveying device with a step-by-step system and normal filling speed is used for this type of line. Of course, everything that is given in this description relates to the aseptic filling mode - the nitrogen and air used are pre-sterilized.

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The nitrogen supply nozzle has a distributor and additional components, such as one or more metal plates, enabling a homogeneous flow at the nozzle outlet.

The nozzle is placed so that it forms an angle between 40 and 50 ° with the vertical.

It is also necessary that the nitrogen flow occurs at a sufficient width to properly remove remaining air from the upper part: a nozzle that is wider than the width of the opening in the packaging is used.

The subject of the invention is shown in the embodiment in the drawing, in which: Figure 1 is a diagram of the device according to the invention at the stage of nitrogen injection, and Figure 2 is the same device at the stage of sealing.

The packages 1 are delivered by the transporting device 2 in the direction of the arrows 3 to the aseptic filling compartment 4 and then to the sealing compartment 5. Sterile air is injected into two compartments 4,5, through pipes 6 and 7 respectively. Product 8 is supplied through the filling system 9 and is dosed into packaging 1 by means of the filling nozzle 10. The sealing compartment 5 has a fixed nitrogen injection nozzle 11, the nitrogen being supplied by pipe 12, as well as two sealing elements 13, 14.

The aseptic filling compartment 4 and sealing compartment 5 have holes 15, 16, 17 through which the packages 1 on the transporting device 2 can pass.

The operation of the device according to the invention is as follows. The transporting device has a step-by-step system. The packaging is placed under the filling nozzle 10, which then delivers a measured quantity of product 8. The compartment is constantly in an atmosphere of sterile air. The conveying device then places further packages under the nozzle 10 and the filled packages are delivered to the sealing compartment 51 passing under the nitrogen injection nozzle 11. The nitrogen flow rate is 300 l / min, and the sealing interval is also constantly in the atmosphere of sterile air. The sealing operation with elements 13 and 14 is clearly visible in Fig. 2. The transporting device 2 then provides ready-to-use or storage packages.

According to the invention, packaging is thus obtained which can be stored for at least 6 months without degrading the quality and taste of the product. In addition, vitamins and mineral salts are stored. The above example gives an oxygen content of 1% in the upper part.

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