EP4304941A1

EP4304941A1 - Packaging gas removing unit for a packing machine, packing machine and packing method

Info

Publication number: EP4304941A1
Application number: EP22770683.5A
Authority: EP
Inventors: Sándor PALLANG
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-03-13
Filing date: 2022-05-13
Publication date: 2024-01-17
Also published as: EP4304941A4; WO2022195311A1; HUP2100107A1; HU231436B1

Abstract

The present patent application relates to a packaging gas-removing unit for a deep-drawing or tray-lidding type packing machines, as well as a packing machine equipped with such a unit, and a packing method. The packaging gas-removing unit contains a sealing tool (4) having a chamber ( 16) adapted to receive a tray ( 1 b) open on one side forming a first element of a package and a closing foil forming a second element of the package for closing the tray ( 1 b) on the open side thereof; the sealing tool (4) is adapted to seal the tray (l b) and the closing foil together; when the tray (l b) is being placed in the chamber (16) it is arranged delimiting a lower space ( 16a) of the chamber ( 16), and when the closing foil is being placed in the chamber (16) it is arranged delimiting an upper space ( 16f ) of the chamber (16); wherein and at least one first opening (22f) is formed in the upper space (16f), and at least one first opening (22a) is formed in the lower space (16a) of the chamber (16) of the sealing tool (4) for discharging gas from the chamber (16), wherein the at least one first openings (22a, 22f) are connected to a vacuum pump.

Description

PACKAGING GAS REMOVING UNIT FOR A PACKING MACHINE, PACKING

MACHINE AND PACKING METHOD The present invention relates to a packaging gas-removing unit for a packing machine; †o a packing machine equipped with such uni†; and †o a packing method for enhancing the durability of food in the package and for sterilization of items, such as medical devices arranged in the package.

A package of perishable foodstuffs, typically meat, poultry, milk and bakery products, is usually filled with a gas mixture, so-called packaging gas, containing oxygen, nitrogen and/or carbon-dioxide †o increase the shelf life of the product. In this way, the amount of microorganisms, pathogens, i.e. bacteria, viruses, fungi, etc., carried by the products in the package can be reduced or their growth can be slowed down. Similarly, other non-organic products, devices, such as medical devices, can be disinfected and sterilized in packaging gas-filled packages.

The most common packing machines developed for this purpose are (flat foil) deep-drawing packing machines, which use plastic foil as packing material; as well as †ray-lidding packing machines. In the former solution, the tray being the lower par† of the package - made from a plastic foil or a foil laminated on paper or a foil laminated on aluminum (aluminum foil) - is also formed on the packing machine, in a deep drawing uni† arranged a† one of its firs† stations.

During packing, the tray and the product arranged in it are closed (sealed) with another closing foil forming the upper par† of the package. The sealing and the packaging gas introduction is performed in a sealing tool of the packing machine. Deep-drawing machines are the most powerful, the most economical †o operate machines and they can be made fully automatic. Tray-lidding packing machines similarly close the package in the machine's sealing tool, but these machines use prefabricated trays; the deep- drawing molding of the frays is performed on another machine af an earlier stage.

Deep-drawing and fray-lidding packing machines generally perform packing with a so-called modified atmosphere operation. This means that the air is pumped out of the space between the fray and the closing foil placed in the sealing fool, reducing the atmospheric pressure originally prevailing there †o a few mBar pressure.

The packaging gas is then injected in between the fray and the closing foil, but they do no† completely refill the package back †o atmospheric pressure, only †o 500-800 mBar. In this way, the packaging gas introduced instead of the pumped out air reaches the entire surface of the product arranged on the fray, making preservation and sterilization more efficient.

The currently used modified atmosphere packing degrades the vital conditions of the pathogens inside the package, greatly reducing or even eliminating their growth. This extends the shelf life of the products.

However, with traditional modified atmosphere packing, pathogens are not or rarely killed. Over time, packing materials allow air and water vapor to pass through from the environment, and pathogens regain their habitat, which leads to product degradation.

Based on our experience so far, ozone treatment with an ozone- containing packaging gas is a very efficient and fast solution. Pathogens on the surface of the product come into contact with ozone directly during packing, leading to their rapid oxidation. The effect is especially fast in case of small viruses and bacteria. Thus, by applying ozone, we not only reduce the function of pathogens, but also eliminate them to a great extent.

However, the problem with the production of gas packages is that some gases, especially ozone-containing gases, have a detrimental effect on the operating personnel of the packing machine and can also be harmful to the environment. This is because when the packaging gas is introduced into the package, a certain amount of the packaging gas inevitably gets info the environment of the package during the sealing of the fray and the closing foil together. Although the packaging gas introduced info the package usually transforms during its sterilizing operation and is no longer a health hazard when the package is opened by the end user, if is necessary †o ensure that if is used in an environmentally friendly manner during packing.

ES1243806U discloses a packing machine in which an ozone-confaining packaging gas is injected info the package through a nozzle †o preserve and sterilize food in a fray being par† of the package †o be made jus† before the tray is sealed with a foil. The timing of the injection is ensured by a control system of the ozone generator used.

No pre-air suction is performed from the tray before the ozone is introduced onto the food, no vacuum pump is used, and the ozone injected essentially displaces the air previously being in the package. Despite the timing of the ozone introduction, a significant shortcoming of this solution is that harmful ozone can easily get †o the workplace.

The utility model document does no† teach how †o safely drain and neutralize the excess ozone escaping from the top and edge parts of the tray during lidding. In addition, the exact composition of the packaging gas applied a† such ven†ing-ou† gas supply is uncertain, which negatively affects the shelf life of the packaged food.

For manufacturing packing machines, UV or so-called germicidal lamp product or package disinfection is often applied. A minimal ozone is always present too as a by-product in these applications, but their safe ozone depletion and neutralization are generally no† ensured.

In connection with the coronavirus (COVID-19) epidemic, the idea has arisen †o develop a device that produces high ozone concentrations and no† primarily UV effects. The discovery of the invention was chiefly induced by this need. The object of the present invention is †o provide a uni† for protecting the operating personnel of a packing machine from the packaging gas entering the package being sealed during packing and for freeing the environment from the this packaging gas. Our object is achieved by a packaging gas-removing uni† as the firs† aspect of the invention, applicable for deep-drawing packing machines or †ray-lidding packing machines, which contain a sealing tool having a chamber adapted †o receive a tray open on one side forming a firs† element of a package and a closing foil forming a second element of the package for closing the tray on the open side thereof; the sealing tool is adapted †o seal the tray and the closing foil together; when the tray is being placed in the chamber it is arranged delimiting a lower space of the chamber, and when the closing foil is being placed in the chamber it is arranged delimiting an upper space of the chamber; wherein a† leas† one firs† opening is formed in the upper space, and a† leas† one firs† opening is formed in the lower space of the chamber of the sealing tool for discharging gas from the chamber, wherein the a† leas† one firs† openings are connected †o a vacuum pump, wherein for introducing gas into the upper space of the chamber a† leas† one second opening is provided on a side of the upper space other than the side containing the a† leas† one firs† opening; further for introducing gas into the lower space of the chamber a† leas† one second opening is provided on a side of the lower space other than the side containing the a† leas† one firs† opening in the sealing tool of the packaging gas-removing uni†.

Preferably each of the a† leas† one firs† openings as well as each of the a† leas† one second openings is provided with a shut-off valve for closing them.

Preferably, the closing of the shut-off valves is timed by a control uni†, such as a PLC.

Preferably atmospheric pressure air is admitted through the a† leas† one second openings †o the upper space and †o the lower space when their shut- off valves are open. The packaging gas-removing uni† preferably comprises a firs† neutralizer, wherein the gas pumped out from the chamber of the sealing tool through the a† leas† one firs† openings is led †o the firs† neutralizer.

The sealing tool is preferably surrounded by a sealing tool separator provided with an inlet door and an outlet door †o ensure the conveying of the tray and the package.

The packaging gas-removing uni† preferably comprises a second neutralizer, wherein the gas in a space partially enclosed by the sealing tool separator is flowed into the second neutralizer by a fan.

Preferably, in the packaging gas-removing uni† a firs† packaging gas meter is provided in the space partially enclosed by the sealing tool separator and/or a second packaging gas meter is provided on the packing machine outside the sealing tool separator.

According †o a second aspect of the invention, there is provided a packing machine for deep-drawing or †ray-lidding packing, containing a sealing tool having a chamber adapted †o receive a tray open on one side forming a firs† element of a package and a closing foil forming a second element of the package for closing the tray on the open side thereof; the sealing tool is adapted †o seal the tray and the closing foil together; and a packaging gas-supply uni† for providing packaging gas †o be delivered between the tray and the closing foil arranged in the chamber, wherein it is provided by a packaging gas-removing uni† according †o the firs† aspect of the invention.

Preferably, the packaging gas contains ozone and the packaging gas- supply uni† is equipped with an oxygen tank and a controlled ozone generator.

A third aspect of the invention is a packing method in which the gas content in the packaging gas-removing uni† according †o the firs† aspect of the invention is reduced below a predetermined health limit †o protect the operating personnel and the environment. The invention will now be described in more detail with reference †o the accompanying drawings, in which:

Figure 1 is a perspective view of a packing machine with a packaging gas-removing uni† according †o the invention;

Figure 2 is a front view of a packing machine equipped with a packaging gas-removing uni† according †o the invention;

Figure 3 is an enlarged view of detail "A" highlighted in Figure 2 with the sealing tool forming the firs† embodiment of the packaging gas-removing uni†;

Figure 4 is a perspective-sectional view of a sealing tool according †o the invention;

Figure 5 is a step sectional view of a sealing tool according †o the invention,

Figure 6 is a front schematic view of an arrangement of the a† leas† one firs† chamber openings and the a† leas† one second chamber openings of the sealing tool;

Figure 7 is a schematic sectional view of the arrangement of chamber openings according †o Figure 5 taken along line B-B;

Figure 8 is a front schematic view of an arrangement of the a† leas† one firs† chamber openings and the a† leas† one second chamber openings of the sealing tool; Figure 9 is a schematic sectional view of the arrangement of the chamber openings according †o Figure 7 taken along line C-C;

Figure 10 shows the firs† ozone neutralizing uni†, and

Figure 11 is a sectional view of the ozone generator.

The firs† aspect of the present invention is a packaging gas-removing uni† 100 for use in a packing machine, particularly of the deep-drawing or tray- lidding type, providing a modified atmosphere packing method. Figure 1 illustrates the packaging gas-removing uni† 100 according †o the invention in a so-called a flat film deep-drawing packing machine 200, also known as a thermoforming packing machine.

The main parts of the packing machine 200 are, in the order of the packing steps: the lower foil feeder 1 and the deep-drawing tool 2 forming a tray 1 b from the lower foil la; a uni† for filling the tray 1 b with a product (no† shown); upper, i.e. closing foil feeder 3, a conveyor 6 for moving the tray 1 b, filled with the product but no† ye† sealed, †o a sealing-gasification tool 4 (hereinafter: sealing tool 4) and for conveying the sealed packages 5 from there, the sealing tool 4, a vacuum pump 7, the packaging gas-supply uni† 8; a cross-cufting tool 9 and a longitudinal cutting tool 10 for separating the blocks of the sealed and packaging gas-filled packages 5, and a package discharging uni† 11, which are arranged substantially on the frame 12 of the packing machine 200.

The basic version of the packaging gas-removing uni† 100 according †o the invention comprises the improved sealing tool 4. Fig. 2 shows a front view of the packing machine 200, and Fig. 3 is an enlarged view of detail A of Fig. 2 showing the sealing tool 4.

The sealing tool 4 generally comprises an upper tool par† 13, a lower tool par† 14 and a lifting device (no† shown) thereof. When opened or closed, the two tool parts 13, 14 move in a vertical direction to each other and perpendicular to the direction of movement of the conveyor 6.

As illustrated in the figures 1-3 the upper fool par† 13 stays in place during opening and closing, only the lower tool par† 14 moves in the direction indicated by the arrow 15, this movement being made possible by the gooseneck design of the gas lines connected †o the lower tool par† 14.

In Fig. 3, parts of the packaging gas-supply uni† 8 are highlighted, in this case an ozone generator 8b for supplying the ozone-containing gas, a line 8e and a packaging gas valve 8d. The sealing tool 4 of the packaging gas-removing uni† 100 according †o the present invention is illustrated in detail with reference †o Figs. 4 and 5. Fig. 4 is a perspective-sectional view of the sealing tool 4 and Fig. 5 is a step- sectional view.

The inner surface of the upper tool par† 13 and the lower tool par† 14 of the sealing tool 4 together delimit a chamber 16, which is suitable for accommodating a tray 1 b, forming the firs† element of the package, filled with a product and a closing foil 3a forming a second element of the package coming from the closing foil feeder 3.

The packing materials la, lb, 3a used can be made, for example, of plastic foil or foil laminated on paper or foil laminated on aluminum (aluminum foil). Figures 4 and 5 also show the valves and lines required †o extract the air in the chamber 16 and †o supply the packaging gas 8c, as well as †o vent out (purge) the spaces surrounding the sealed package 5 of the chamber 16 in accordance with the present invention. With the tool setting shown in the Figure 5, in the sectional direction, i.e. in the direction parallel †o the direction of travel of the conveyor 6, it is possible †o receive two trays 1 b in the chamber 16 of the sealing tool 4, which is from time †o time modified by replacing the appropriate tool inserts, depending on the tray sizes. (Figure 1 illustrates a tray block comprising two trays 1 b parallel to, and three trays 1 b perpendicular †o the direction of travel of the conveyor 6.)

The separation of the packages 5 (package block) closed simultaneously in the sealing tool 4 takes place a† later stations by means of the cross-cu††ing tool 9 and the longitudinal cutting tool 10. The set of trays 1 b placed in the chamber 16 simultaneously, formed from a single continuous film la, thus make a tray block; however, for the sake of simplicity, such an unseparated tray block is also referred †o as tray 1 b in the present application.

The tray 1 b arranged in the chamber 16 rests along its edge on a resilient element 17, typically a rubber, located on the edge support formed in the lower tool par† 14, thereby substantially delimiting the lower space 16a of the chamber 16. The closing foil 3a fed into the chamber 16 and placed onto the tray 1 b, likewise substantially delimits the upper space 16f of the chamber 16.

The upper space 16f of the chamber 16 so separated comprises the components used †o close and seal the tray 1 b and the closing foil 3a together, namely the heating plate 18, the pressure plate 19, the returning springs (no† shown), the heater 20 and the pressure pad 21 , the operation of the latter is ensured by compressed air flowing in a compressed air channel 50.

The upper space 16f encompasses these components; the upper space 16f is therefore no† so unitary an area with respect †o the lower space 16a. Although dependent on the tray size, in most cases the upper space 16f is smaller than the lower space 16a, which affects the timing and duration of the suction and inlow of gas.

The third, intermediate space 16k formed in the chamber 16 is located between the tray l b and the closing foil 3a. A cooling water channel 49 is formed in the wall of the upper tool par† 13, the arrow 51 indicating the inlet of cooling water.

For discharging gas (for pumping out air or air - packaging gas mixture) from the chamber 16, a† leas† one firs† opening 22f in the wall of the upper tool par† 13 is formed coming from the upper space 16f; and a† leas† one firs† opening 22a in the wall of the lower tool par† 14 is formed coming from the lower space 16a of the chamber 16 of the sealing tool 4.

For this purpose, in general, the intermediate space 16k, i.e. the space 16k between the tray l b and the closing foil 3a, also has a† leas† one firs† opening 22k formed in the wall of either the upper tool par† 13 or the lower tool par† 14. In general, there is one firs† opening 22a, 22f, 22k associated with the lower space 16a, the upper space 16f and the intermediate space 16k, respectively, however, there can also be a solution where the lower space 16a has two firs† openings 22a which are formed on two opposite side walls of the lower 14 tool par†.

I† is also possible for the upper space 16f to have two firs† openings 22f, which are likewise formed on two opposite side walls of the upper tool par† 13. Generally however, only one firs† opening 22k is associated with the intermediate space 16k. The a† leas† one firs† openings 22a, 22f, 22k are connected †o the vacuum pump 7 and are provided with separate shut-off valves 24, 25, 26, so-called vacuum valves, respectively, for opening or closing them.

Figures 4 and 5 illustrate the lower vacuum valve 24, which is an opening/closing valve associated with the at least one first opening 22a belonging †o the lower space 16a; the upper vacuum valve 25 is an opening/closing valve associated with the a† leas† one firs† opening 22f belonging †o the upper space 16f, and the intermediate vacuum valve 26 is an opening/closing valve associated with the a† leas† one firs† 22k opening belonging †o the intermediate space 16k. The vacuum valves 24, 25, 26 are generally arranged directly on the outer wall of the upper fool par† 13 and the lower tool par† 14, respectively, covering from the outside the a† leas† one firs† channel formed in the wall leading from the opening 22a, 22f, 22k. The a† leas† one firs† opening 22a, 22f, 22k generally continues as a channel in the wall of the upper tool par† 13 and in the wall of the lower tool par† 14, examples of this can be seen in Figures 4 and 5: channel 22kcs leading †o the firs† opening 22k, and channel 22fcs leading †o the firs† opening 22f.

A† leas† one gas nozzle (no† shown) is used †o introduce gas into the intermediate space 16k, from which nozzle the packaging gas 8c lifts - a† one place - the closing foil 3a having been arranged covering the tray 1 b, so that the packaging gas 8c enters the intermediate space 16k, before the assembly of the heating plate 18 and the pressure plate 19 of the sealing tool 4 would seal the closing foil 3a onto the tray 1 b. The valve 8d is a packaging gas valve forming par† of the packaging gas-supply uni† 8, which is arranged on the outer surface of the lower tool par† 14 †o open/close the packaging gas inlet formed as a channel in the wall of the lower tool par† 14.

During the sealing of the tray 1 b and the closing foil 3a arranged in the chamber 16 of the sealing tool 4, a certain amount of packaging gas 8c may enter the res† of the chamber 16, i.e. the lower space 16a and the upper space 16f. The present invention seeks †o rid the working environment of the packing machine of this packaging gas residue by providing a multi-stage safety system, namely a packaging gas-removing uni† 100.

The parts of the sealing tool 4 taught so far belong †o the prior art. In connection with the improved sealing tool 4, there is a need for a more efficient post-sealing chamber-venting due †o the use of packaging gases 8c with enhanced preservation functions, such as ozone-containing packaging gases 8c. The effective removal of the gases 8c - which during packing are harmful †o the environment and †o the operating persons - from the chamber 16 after the sealing of the package 5 is ensured in the sealing fool 4 according †o the invention.

The inventive realization is as follows. While af the prior approaches, after sealing, the pressurization of the chamber 16 †o atmospheric pressure is done through the af leas† one firs† openings 22a and 22f used also for the previous air-pumping out -, in the sealing fool 4 of the present invention, separate second openings 29a, 29f are provided for this purpose.

The obvious approach for a person skilled in the art would therefore be †o use an already available opening 22a, 22f both for pumping out the air before the package is closed and also for setting the chamber 16 under atmospheric pressure after the package has been closed. This only requires the installation of a T-branch in the section between the shuf-off valves (vacuum valves) 24, 25 belonging †o the respective first openings 22a, 22f, outside the sealing tool 4, and the wall of the sealing tool 4; hence, it is easy to ensure these two functions. However, with this simple solution, a certain amount of unwanted packaging gas 8c can remain in the lower space 16a and the upper space 16f of the chamber 16, which enters the environment of the packing machine when the sealing tool 4 is opened.

To avoid this, for the complete gas displacement of the packaging gas 8c before the opening of the sealing tool 4 (and then for discharging the displaced gas), i.e. for completely venting out the lower space 16a and the upper space 16f of the chamber 16, the basic version of the packaging gas- removing unit 100 of the present invention is as follows.

In the sealing tool 4 at least one second opening 29f is formed in the wall of the upper tool part 13 for the introduction of gas into the upper space 16f of the chamber 16 (for the introduction of atmospheric pressure air indicated by the arrow 30); wherein the at least one second opening 29f is formed on a side of fhe upper space 16f different from the side containing the af leas† one firs† opening 22f.

Furthermore, in fhe sealing fool 4, af leas† a second opening 29a is formed in fhe wall of fhe lower fool par† 14 for fhe introduction of gas info fhe lower space 16a of fhe chamber 16 (for fhe introduction of atmospheric pressure air indicated by fhe arrow 30). The af leas† one second opening 29a is formed on a side of fhe lower space 16a different from fhe side containing fhe af leas† one firs† opening 22a.

Like fhe af leas† one firs† openings 22a, 22f, 22k, fhe af leas† one second openings 29a, 29f are also each associated with a shuf-off valve 27, 28, namely fhe lower venting valve 27 and fhe upper venting valve 28. Atmospheric pressure air 30 is thus introduced through fhe af leas† one second openings 29a, 29f info fhe upper space 16f and fhe lower space 16a, respectively, of fhe chamber 16 from a side other than fhe side containing fhe af leas† one firs† openings 22a, 22f for pumping out gas.

As a result, if is ensured by means of flow technology that fhe air containing a certain amount of unwanted packaging gas 8c in fhe lower space 16a as well as in fhe upper space 16f of a more complex space design, is completely displaced and discharged through fhe lines. In this way, during standard operation, when fhe sealing fool 4 is opened, no air containing harmful packaging gases 8c can enter fhe environment of fhe packing machine 200.

The opening and closing of fhe shuf-off valves 24-28 is timed by a control unit, typically a PLC unit. The af leas† one second opening 29a, 29f optionally continues as a channel in fhe wall of fhe upper fool par† 13 and in fhe wall of fhe lower fool par† 14, respectively; examples thereof are channel 29acs leading †o second opening 29a, and channel 29fcs leading †o second opening 29f as shown in Figures 4 and 5. The firs† opening 22k and the second opening 29f according †o the invention are illustrated in the schematic Figures 6 and 8.

Figures 6-9 show an arrangement scheme of the at least one first opening 22a, 22f and at least one second opening 29a, 29f associated with the lower space 16a and the upper space 16f of the chamber 16 according to the invention. In the front view illustrated in Figure 6, both the lower space 16a and the upper space 16f have two first openings 22a, 22f arranged on opposite sides of the spaces 16a, 16f.

Fig. 7 also shows two second openings 29a formed in the lower space 16a of the arrangement according to Fig. 6, which are arranged on different sides than the first openings 22a, and just like those: opposite to each other. According to the invention, a similar second opening arrangement is conceivable in the upper space 16f of Fig. 6, which is not shown. In Figures 8 and 9, there are only one first openings 22a, 22f and one second opening 29a, 29f in both the upper space 16f and the lower space 16a.

As it can be seen in Figure 2, the second embodiment of the packaging gas-removing unit 100 according to the invention further comprises a first neutralization unit 31 .

As an additional safety measure, the air - incidentally containing any packaging gas 8c - that is pumped out of the lower space 16a and the upper space 16f of the chamber 16 of the still closed sealing tool 4 by the high- capacity vacuum pump 7, which is used to vacuum the sealing tool 4, enters a first neutralizer 31 installed downstream of the vacuum pump 7 through an inlet 48, where any packaging gas 8c in the pumped air is neutralized.

If the packaging gas 8c is an ozone-containing gas-mixture, one possible embodiment of the first neutralizer 31 (first ozone neutralizer) is a first neutralizer with an electron tube 33 shown in FIG. 10. By this, the known method is adapted, in which a packaging gas 8c pumped out from the chamber 16 of the sealing fool 4 is passed around the electron tube 33 in a long channel 34 (mixing cell) such that the arc of the electron tube 33 has a wavelength of approximately 250 nm transforming the ozone again †o oxigene, †o the extent required by health and/or environmental regulations.

As a further safety measure in the third embodiment of the packaging gas-removing uni† 100 according †o the invention, the sealing tool 4 is surrounded by a sealing tool separator 35, thereby arranged in a partially enclosed space 36, which arrangement is shown in Figures 1 and 2.

The sealing tool separator 35 is connected †o a second neutralizer 32. As shown in Fig. 2, the separator 35 is provided with an inlet door 38, preferably insulated, and an outlet door 39, preferably insulated, in order that the sealing tool separator 35 can be opened for receiving the incoming new tray 1 b †o be sealed on the conveyor 6; and for releasing the sealed package 5 already in the sealing tool 4 on the conveyor 6.

During operation of the sealing tool 4, the inlet door 38 and the outlet door 39 are closed. As described above, the sealing tool 4 is designed †o remove air containing any packaging gas 8c from the lower space 16a and the upper space 16f which have been created after the tray 1 b and the closing foil 3a have been arranged/sealed in the chamber 16 so that prior †o the opening of the sealing tool 4, the packaging gas-con†en† is below a health limit.

Thus, it is ensured that air with a high packaging gas-con†en† does no† enter the (partially enclosed) space 36 formed by the sealing tool separator 35 when the sealing tool 4 is opened after the package-closing (sealing) operation. From the space 36 partially enclosed by the separator 35 provided with an inlet door 38 and an outlet door 39, the air incidentally containing any packaging gas 8c is sucked out by a continuously working fan 37. Here, the second neutralizer 32 is installed upstream of the fan 37. If the packaging gas 8c contains ozone, the second neutralizer 32 (the second ozone neutralizer) is a uni† preferably similar in design †o the electron tube uni† 33 described as the firs† ozone neutralizer.

As the vacuum valves 24, 25, 26 are preferably arranged directly on the outer wall of the upper tool par† 13 and the lower tool par† 14, respectively, covering - from the outside - the channel leading from the a† leas† one firs† outlet 22a, 22f, 22k; the shut-off valves 27, 28 (the venting valves) are also arranged on the wall of the upper tool par† 13 and the lower tool par† 14, respectively.

However, in the case where the packaging gas-removing uni† 100 is also provided with a sealing tool separator 35, the shut-off valves 27, 28 are preferably mounted on the outer surface of the separator 35 on the outer side of the partially enclosed space 36, so that when the lower and upper chamber spaces 16a, 16f are being set †o atmospheric pressure, for their venting packaging gas-free air could be applied in any way, as shown in Figure 2.

The gas mixture (air) neutralized from the packaging gas 8c in the firs† neutralizer 31 or the second neutralizer 32 †o an extent complying with a predetermined health limit, is released into the environment outside the building via a firs† neutralized gas outlet pipe 40 and the second neutralized gas outlet pipe 41 , respectively.

This is expedient because in buildings where a packing process takes place - i.e. in a basically pressurized system - ventilation of the building is usually no† feasible.

The firs† neutralizer 31 installed downstream of the vacuum pump 7, and its capacity must always be constructed according †o the capacity of the vacuum pump 7 and the size of the sealing tool 4; while the performance of the second neutralizer 32 downstream of the space 36 partially enclosed by the sealing tool separator 35 depends only slightly on the selection of these packing machine units.

Ozone neutralization solutions known in other engineering fields typically have a continuous flow of ozone-enriched air. In contras†, in the third embodiment of the present invention, the second ozone neutralizer 32 after the space 36 partially enclosed by the sealing tool separator 35 is of pulsing operation, since only after the opening of the sealing tool 4 can ozone enter the partially enclosed space 36. In relation †o the second embodiment of the present invention, the air mixed with ozone pumped out from the sealing tool 4 is also pulsed. Therefore, in both cases, the firs† and second ozone neutralizers 31 and 32, respectively, are designed †o compensate for the pulsating load and †o achieve neutralization during the breaks and †o prevent air with a high ozone content from escaping into the atmosphere during working hours. The electron-tube neutralizer 31, 32 taught in the present application is suitable for this purpose by providing a long flow design for the gas †o be neutralized as shown in Fig. 9.

The packaging gas-removing uni† 100 is preferably provided with two packaging gas - optionally ozone - limit value moniforing-measuring- infervenfion subsystem. One of these subsystems is intended †o monitor and maintain the limit †o be below a limit of the healthy packaging gas limit, possibly the ozone limit, within the space 36 that separates the sealing uni† from the environment, and the other in the vicinity of the packing machine where the operators are located, †o protect the health of the operators.

Accordingly, a firs† gas meter 42, optionally an ozone concentration meter, is placed in the space 36 partially enclosed by the sealing tool separator 35 and if the gas level rises substantially here, it is already possible †o intervene in order †o prevent the gas load on the environment of the packing machine 200.

A second gas meter 43, optionally an ozone level meter, is also placed in the vicinity of the packing machine 200, preferably on a stand of the closing foil feeder 3, above the sealing fool 4. By keeping the environment of the packing machine 200 in a continuous control with a measuring instrument, a signal is given †o the operating personnel when the health limit is reached and further operation is stopped, thus ensuring safe operation.

A second aspect of the present invention is a packing machine 200 with a packaging gas-removing uni† 100 as described above, having a sealing tool 4 according †o the firs† aspect of the invention, and a packaging gas-supply uni† 8 provided with a packaging gas tank 8a for providing a packaging gas 8c †o be supplied between the tray 1 b and the closing foil 3a arranged in the chamber 16 of the sealing tool 4. The packaging gas 8c may be a gas mixture containing oxygen, nitrogen, carbon-dioxide, and the like. The packaging gas 8c preferably contains ozone and the packaging gas-supply uni† 8 is equipped with an oxygen tank 8a (oxygen cylinder) and connected thereto with a controlled ozone generator 8b equipped with an ozone level sensor 47. A preferred version of the ozone generator 8b as shown in Figure 10 comprises an opening 45 for the introduction of an oxygen-containing gas, an electron tube 44 and an opening 46 for the discharge of an ozone-enriched gas, which generates an ozone in a predetermined ratio from the gas obtained from the oxygen cylinder 8a a† a wavelength of approximately 185 nm.

The ozone-oxygen-containing gas mixture as packaging gas 8c enters the intermediate space 16k of the chamber 16 of the sealing fool 4 from the ozone generator 8b via a line 8e and a gas nozzle. The use of the packaging gas-removing uni† 100 may optionally involve a machine-specific control system, a power control, a vacuum valve system, a pneumatic system, a frame, a mechanical design, which are adaptations that can be implemented by a person skilled in the art.

A third aspect of the present invention is a packing method applying the packaging gas-removing uni† 100 described above. The operation of the invention will be described with reference †o the packing method.

The packing method is carried out on a packing machine 200 suitable for the modified atmosphere packing of a food or, optionally, medical device, provided with a packaging gas-removing uni† 100 according †o the second aspect of the invention, which method comprises the following steps: a) preparing a tray 1 b forming the lower par† of the package and a closing foil 3a forming the upper par† of the package, b) placing the product †o be packaged on the tray 1 b, c) placing the tray l b containing the product and the closing foil 3a in the sealing tool 4 - arranged on a package-closing station - with a chamber 16 adapted †o receive the tray lb and the sealing foil 3a, whereby the tray 1 b is arranged †o define the lower space 16a of the chamber 16 and the closing foil 3a is arranged †o define the upper space 16f of the chamber 16; wherein by placing the closing foil 3a on the tray l b an intermediate space 16k delimited by them is formed, which is associated with a firs† chamber opening 22k provided with a shut-off valve 26, d) closing the sealing tool 4, e) opening the upper vacuum valve 25 closing a† leas† one firs† opening 22f formed in the upper space 16f, the lower vacuum valve 24 closing the a† leas† one firs† opening 22a formed in the lower space 16a of the chamber 16 of the sealing tool 4, and the intermediate vacuum valve 26 closing the firs† opening 22k, designed for fhe intermediate space 16k of the chamber

16, f) pumping air out through fhe af leas† one firs† opening 22f formed in fhe upper space 16f, and through fhe af leas† one firs† opening 22a formed in fhe lower space 16a and through fhe firs† opening 22k formed for fhe intermediate space 16k †o a predetermined firs† pressure value, typically up †o 15 mBar, preferably less than 2 mBar, more preferably less than 1 mBar. g) closing fhe firs† opening 22k belonging †o fhe intermediate space 16k (by closing its shuf-off valve 26), then introducing packaging gas 8c by fhe packaging gas-supply unit 8 †o fhe intermediate space 16k (i.e. in between fhe fray lb and fhe closing foil 3a in fhe chamber 16 of fhe sealing fool 4), fhe posf-infroducfion pressure of which within fhe infermedife space 16k is a predetermined second pressure, which is lower than fhe atmospheric pressure, if is preferably 300-800 mBar. h) sealing fhe closing foil 3a and fhe fray 1 b together along its edge by applying compressed air †o fhe opening 50 for a predetermined time, i) for venting out fhe upper space 16f and fhe lower space 16a, opening fhe shuf-off valves 27, 28, i.e. fhe af leas† one lower venting valve 27 and fhe af leas† one upper venting valve 28 associated with fhe af leas† one second opening 29f formed in fhe upper space 16f, as well as fhe af leas† one second opening 29a formed in fhe lower space 16a of fhe chamber 16 of fhe sealing fool 4, j) after a predetermined time relative †o fhe previous step, typically one †o forty hundredths of a second, closing fhe shuf-off valves of fhe af leas† one openings 22f and 22a formed in fhe upper space 16f, and fhe lower space 16a; i.e. fhe af leas† one upper vacuum valve 25 and fhe af leas† one lower vacuum valve 24, k) setting the upper space 16f and the lower space 16a under atmospheric pressure by admitting atmospheric pressure air 30 into the upper space 16f and the lower space 16a through the at least one second orifices 29a, 29f,

L) opening the sealing tool 4, m) removing the sealed package 5 from the sealing fool 4.

Preferably, the packaging gas 8c is an ozone-containing gas mixture, and prior †o step g), ozone is produced from the oxygen taken from the oxygen tank 8a in the ozone generator 8b, where the ozone concentration is measured and controlled.

In step i), optionally, the shuf-off valve (venting valve) 27, 28 belonging †o a† leas† one second opening 29a, 29f of one of the spaces 16a, 16f is opened earlier than the other. This is typically a† leas† one lower venting valve 27 formed in the lower space 16a, since the volume of the lower space 16a is generally larger than that of the upper space 16f, and thus a larger amount of air must be supplied †o the lower space 16a. This prevents the pressure difference due †o the volume difference from squeezing the assembly of the tray 1 b and the closing foil 3a or the sealed package 5 into the lower space 16a, or from squeezing the assembly of the tray 1 b and the closing foil 3a or the sealed package 5 into the heating plate 18.

In steps f) †o j) , the gas pumped out of the a† leas† one firs† opening 22a, 22f, 22k is preferably introduced into the firs† neutralizer 31, where any packaging gas 8c present is neutralized.

Preferably, the sealing tool 4 is surrounded by a separator 35, and the gas in the space 36 partially enclosed by the separator is continuously passed by a fan 37 to the second neutralizer 32, where any packaging gas 8c incidentally present is neutralized.

Preferably, the air that is neutralized from packaging gas 8c in the firs† neutralizer 31 or in the second neutralizer 32 is flowed into the environment via outlet pipes 40, 41 connected †o the neutralizers 31 , 32. By way of example, the following deep-drawing or fray-lidding packing machines 200 may be supplemented with the packaging gas-removing unit 100 described above: fable fop chamber packaging machines, vertical chamber packaging machines, vertical double chamber packaging machines, chamber belt packing machines, drawer fray sealers, rotary fray sealers, continuous fray sealing machines, fhermoforming deep draw fray forming packaging machines, which pack by applying a modified atmosphere method. The invention proves †o be the most justified and economical supplement †o continuous fray-lidding and especially fhermoforming-deep drawing packing machines.

The packaging gas-removing unit 100 of the present invention has a negligible effect on the performance and speed of the packing machine 200. The environmental impact can be minimized by installing and using gas neutralizing and, optionally, ozone neutralizing units. The gas monitoring (typically ozone monitoring) system eliminates harmful effects on individuals. Operating costs do not change significantly, only minimal electricity costs emerge.

Claims

1 . Packaging gas-removing uni† ( 100) for packing machines (200) of deep-drawing or †ray-lidding type, containing a sealing tool (4) having a chamber (16) adapted †o receive a tray (l b) open on one side forming a firs† element of a package and a closing foil (3a) forming a second element of the package for closing the tray (l b) on the open side thereof; the sealing tool (4) is adapted †o seal the tray ( 1 b) and the closing foil (3a) together; when the tray (l b) is being placed in the chamber (16) it is arranged delimiting a lower space ( 16a) of the chamber ( 16) , and when the closing foil (3a) is being placed in the chamber (16) it is arranged delimiting an upper space (16f) of the chamber (16); wherein a† leas† one firs† opening (22f) is formed in the upper space (16f), and a† leas† one firs† opening (22a) is formed in the lower space (16a) of the chamber (16) of the sealing tool (4) for discharging gas from the chamber (16), wherein the a† leas† one firs† openings (22a, 22f) are connected †o a vacuum pump (7), characterized in that for introducing gas into the upper space ( 16f) of the chamber (16) a† leas† one second opening (29f) is provided on a side of the upper space (16f) other than the side containing the a† leas† one firs† opening (22f); further for introducing gas into the lower space ( 16a) of the chamber (16) a† leas† one second opening (29a) is provided on a side of the lower space ( 16a) other than the side containing the a† leas† one firs† opening (22a) in the sealing tool (4) of the packaging gas- removing uni† (100).

2. Packaging gas removing uni† (100) according †o claim 1 , characterized in that each of the a† leas† one firs† openings (22a, 22f) is provided with a shut-off valve (24, 25) for closing them, and each of the a† leas† one second openings (29a, 29f) is provided with a shut-off valve (27, 28) for closing them.

3. Packaging gas-removing uni† (100) according †o claim 2, characterized in that the closing of the shut-off valves (24, 25, 27, 28) is timed by a control uni†, such as a PLC.

4. Packaging gas-removing uni† (100) according †o claim 2 or 3, characterized in that atmospheric pressure air (30) is admitted through the a† leas† one second openings (29a, 29f) to the upper space (16f) and †o the lower space ( 16a) when the associated shut-off valves (27, 28) are open.

5. Packaging gas-removing uni† (100) according †o any one of the preceding claims characterized in that i† further comprises a firs† neutralizer (31), wherein the gas pumped out from the chamber (16) of the sealing tool (4) through the a† leas† one firs† openings (22a, 22f) is led †o the firs† neutralizer (31).

6. Packaging gas-removing uni† (100) according †o any one of the preceding claims characterized in that the sealing fool (4) is surrounded by a sealing tool separator (35) provided with an inlet door (38) and an outlet door (39) to ensure the conveying of the tray (l b) and the package (5).

7. Packaging gas-removing uni† (100) according †o claim 6, characterized in that i† further comprises a second neutralizer (32), wherein the gas in a space (36) partially enclosed by the sealing tool separator (35) is flowed into the second neutralizer (32) by a fan (37).

8. Packaging gas-removing uni† (100) according †o claim 6 or 7, characterized in that a firs† packaging gas meter (42) is provided in the space (36) partially enclosed by the sealing tool separator (35) and/or a second packaging gas meter (43) is provided on the packing machine (200) outside the sealing tool separator (35).

9. Packing machine for deep-drawing or †ray-lidding packing, containing a sealing tool (4) having a chamber ( 16) adapted †o receive a tray (l b) open on one side forming a firs† element of a package and a closing foil (3a) forming a second element of the package for closing the tray ( 1 b) on the open side thereof; the sealing tool (4) is adapted †o seal the tray ( 1 b) and the closing foil (3a) together; and a packaging gas-supply uni† (8) for providing packaging gas (8c) †o be delivered between the tray (l b) and the closing foil (3a) arranged in the chamber (16), characterized in that i† is provided by a packaging gas-removing uni† ( 100) according †o any one of claims 1 -8.

10. Packing machine (200) according †o claim 9, characterized in that the packaging gas (8c) contains ozone and the packaging gas-supply unit (8) is equipped with an oxygen tank (8a) and a controlled ozone generator (8b).

11. Packing method for packing a product in modified atmosphere on a packing machine (200) according †o any one of claims 9 or 10, which method comprises the steps of: a) preparing a fray (lb) forming the lower par† of the package and a closing foil (3a) forming the upper par† of the package, b) placing the product †o be packaged on the tray (lb), c) placing the tray (lb) containing the product and the closing foil (3a) in the sealing tool (4) with a chamber (16) adapted †o receive the tray (lb) and the sealing foil (3a), whereby the tray (1 b) is arranged †o define the lower space ( 16a) of the chamber ( 16) and the closing foil (3a) is arranged †o define the upper space ( 16f) of the chamber (16); wherein by placing the closing foil (3a) on the tray ( 1 b) an intermediate space ( 16k) delimited by them is formed, which is associated with a firs† chamber opening (22k) provided with a shut- off valve (26), d) closing the sealing tool (4) e) opening the valve (25) closing the at least one first opening (22f) formed in the upper space (16f); as well as the valve (24) closing the a† leas† one firs† opening (22a) formed in the lower space (16a) of the chamber (16) of the sealing tool (4), f) pumping air out through the a† leas† one firs† opening (22f) formed in the upper space ( 16f), and through the a† leas† one firs† opening (22a) formed in the lower space (16a) and through the firs† opening (22k) formed for the intermediate space (16k) †o a predetermined firs† pressure value, g) closing the shut-off valve (26) of the firs† opening (22k) of the intermediate space (16k) and then introducing packaging gas (8c) †o the intermediate space (16k) by means of the packaging gas-supply uni† (8), wherein the pressure of the packaging gas (8c) after the packaging gas- introduction is a predetermined second pressure, which is lower than atmospheric pressure, h) sealing the closing foil (3a) and the tray (l b) together a† the edge thereof, i) opening the shut-off valves (27, 28) associated with the a† leas† one second opening (29f) formed in the upper space (16f), as well as the a† leas† one second opening (29a) formed in the lower space (16a) of the chamber (16) of the sealing tool (4), for venting out the upper space (16f) and the lower space (16a), j) after a predetermined time relative †o the previous step, closing the shut-off valves (24, 25) of the a† leas† one firs† openings (22f, 22a) formed in the upper space (16f) and in the lower space (16a), k) setting the upper space (16f) and the lower space (16a) under atmospheric pressure,

L) opening the sealing tool (4), m) removing the sealed package (5) from the sealing tool (4).

12. Packing method according †o claim 11 , characterized in that an ozone-containing gas mixture is applied as packaging gas (8c) and, before step g), from the oxygen taken from the oxygen tank (8a) ozone is produced in the ozone generator (8b), wherein the ozone concentration is measured and controlled.

13. Packing method according †o claim 11 or 12, characterized in that in steps f) †o j) the gas pumped out through the a† leas† one firs† openings (22a, 22f, 22k) is introduced into the firs† neutralizer (31), wherein any packaging gas (8c) present is neutralized.

14. Packing method according †o any one of claims 11 †o 13, characterized in that the sealing tool (4) is surrounded by a separator (35) and the gas in the space (36) partially enclosed by the separator (35) is continuously flowed into the second neutralizer (32), wherein any packaging gas (8c) incidentally present is neutralized.

15. Packing method according †o claim 13 or 14, characterized in that the air that is neutralized from packaging gas (8c) in the firs† neutralizer (31) or in the second neutralizer (32) is flowed into the environment via outlet pipes (40, 41 ) connected †o the neutralizers (31 , 32).

16. Packing method according to any one of claims 11 †o 15, characterized in that the firs† pressure value set in step f) is a† most 15 mBar.

17. Packing method according †o any one of claims 11 †o 16, characterized in that the second pressure value set in step g) is 300-800 mBar.

18. Packing method according to any one of claims 11 †ol 7, characterized in that the time used in step j) is 0,01 to 0,4 seconds.