ZA200105967B

ZA200105967B - Method and device for sterilisation of packaging containers.

Info

Publication number: ZA200105967B
Application number: ZA200105967A
Authority: ZA
Inventors: Erwin Knieling; Hans Hiendl
Original assignee: Krones Ag
Priority date: 1999-11-22
Filing date: 2001-07-19
Publication date: 2002-10-21
Also published as: AU1276401A; ATE255912T1; JP4733892B2; CN1336829A; EP1144016B1; BR0007636B1; EP1144016A1; BR0007636A; WO2001037886A1; CN1222323C; JP2003514624A; DE50004720D1; RU2243138C2; ES2211642T3; DE19956186A1

Abstract

The invention relates to a method for the sterilisation of packaging containers, in particular, bottles, whereby a mixing jet is simultaneously, separately fed with a fluid disinfecting agent and steam. The mixed stream, emanating from the mixing jet, of nebulised and/or vaporised disinfecting agent and steam is led directly onto and into the packaging container. Said method is easily achieved, works reliably and permits a reliable sterilisation of packaging containers with a relatively narrow opening.

Description

) | PCT/EP00/10611 } y Method and Device for the Sterilization of Packaging Containers

Description

The mvention relates to a method for the stabilization of packaging containers according to the preamble of Claim 1, and to a suitable device according to the preamble of Claim 13

Such a method is already known, in which a H,O;-steamn mixture is led through a two-substance nozzle and a heating chamber, as well as a pipe, into a sterilization chamber (DE 39 00 448 Al).

The packaging containers to be treated, which are in the form of conical beakers made of plastic, are moved through the sterilization chamber, and exposed in the process to a diffuse, heated, mixture of H,0; and steam. In addition, hot air is blown into the sterilization chamber for the purpose of decomposing the HO. Then the remainders of the sterilization agent and of the : mixture are removed by suction from the sterilization chamber.

The course of this known method is very complex and accordingly it is expensive to use.

Because of the undirected, diffuse, introduction of the mixture of H,Q, and steam into the sterilization chamber, it is only suitable for packaging containers having a relatively large mouth opening, and not for packaging containers having a small opening, such as, for example, plastic bottles for drinks, which are increasingly used in the drink industry.

A known method also exists which is designed fro the sterilization of PET bottles, where peracetic acid at a concentration of 0.1-1.5% is continuously sprayed into a pipe which carries pressurized aif; by means of an atomization nozzle (DE 198 08 318 Al). The aerosol so formed is then heated ina heat exchanger, and then it is led through pipes and single-component nozzles into inverted PET bottles. After the exposure, the sterilization agent is removed by rinsing the

PET bottles by spraying demineralized water.

Although this method can also be used to sterilize packaging containers with a small neck, its use requires very expensive equipment. An additional problem arises during the unavoidable 1

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PCT/EP00/10611 " #8 ropiions in the operation, When the heated aerosol can condense in the long pipes leading to the nozzles. This leads to imperfectly sterilized packaging containers after the interruption. li

The invention is based on the problem of providing a method which is simple to use and which works reliably for the sterilization of packaging containers, by means of which packaging containers having a relatively small mouth opening can also be reliably sterilized. In addition, a cost effective device for using the method is described.

This problem 1s solved, as far as the method is concemed, by the characteristics of Claim 1, and, as far as the device 1s concerned, by the characteristics of Claim 13.

In the method according to the invention, both the atomization or evaporation as well as the heating of the liquid disinfectant occur solely by mixing with steam. In this context, the heating can be defined most simply by choosing the temperature and the quantity of the steam. The resulting “dilution” can also be compensated for in a simple manner by a corresponding increase in the initial concentration of the disinfectant which is led into the mixing nozzle, so that the mixture which condenses on the packaging containers, which are preferably at room temperature, presents the desired concentration.

Because of the direct application by spraying of the disinfectant-steam mixture onto the packaging containers by the mixing nozzles, no heating chamber, pipes etc. are needed, in which the mixture could condense. The mixing nozzles can thus be operated in cycles, and even longer interruptions of the operation have no negative effects. By an appropriate design of the mixing nozzles, and the resulting shape of the jets of the mist-like mixture, the latter can be blown or applied as-a mist mto narrow mouth openings or broadside onto the external wall of packaging containers. In addition, it is possible to set an exact dosage of the mixture which is applied as a mist onto a packaging container, and thus achieve a considerably saving In consumption.

Advantageous embodiments of the invention are provided in the dependent claims.

In the following embodiment example, the invention is described with reference to the drawings.

In the drawings, 2

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PCT/EP00/10611 - t.. 1 1s a schematic top view of a device for the sterilization of packaging containers

Figure 2 1s a cross section along AA in Figure 1 at an enlarged scale } Figure 3 1s detail X at an enlarged scale

Figure 4 is a cross section along CD in Figure 1 at an enlarged scale

Figure 5 1s a cross section along EF in Figure 1 at an enlarged scale

The device of Figures 1-5 is designed for the sterilization of packaging containers in the form of

PET bottles for drinks, which hereafter will be called bottles 1 for short. It essentially comprises an injection machine 5, a rinsing machine (rinser) 6, and a conveyor 7 which connects the two machines. The bottles 1 to be sterilized are led to the device by an input convevor §, while they are in an upright position; the sterilized bottles 1 are led away from the device, while in an upright position, by an output conveyor 9.

The injection machine 5 has a stationary housing 10, on which a rotating table 11 with a vertical rotating axle 12 is located. On the circumference of the rotating table 11, 2a number of elastic gripping tongs 13 according to European Paten 721 808 are ngidly attached, in an even distribution. These gripping tongs 13 hold the bottles 1 by a section below the collar of the neck in an upright position and with the opening turned upward, while the bottles move in a rotating path with the rotating table 11. The introduction and the removal of the bottles 1 into/out of the gripping tongs 13 occur by means of a one-part worm 14, an input star 17, as described in detail in the mentioned European Patent 721 808. A pivoting of the bottles by 180° does, however, not occur. In the crosshatched treatment area, the bottles always remain in the upright normal position.

Moreover, on the rotating table 11 of the injection machine 5 a number of two-component atomization nozzles with a spraying angle of approximately 20°, hereafter called Mixing nozzles 2 for short, are rigidly attached. More precisely, above each gripping tong 13, concentrically with respect to a bottle 1 held by the gripping tong, a mixing nozzle 2 is directed vertically downward in each case, and at a small distance (approximately 2 cm) from the mouth opening of the bottle 1. 3

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PCT/EP00/10611 ~ fg. first duct 18 of each mixing nozzle 2 is connected above the first lines 22 with intercalation of a first control valve 20 and a rotating distributor 27 arranged concentrically with respect to the : rotating axle 12 to a stationary steam generator 24. The latter delivers steam at an excess pressure of 2 bar and a temperature of 121°C. The second duct 19 of each mixing nozzle 2 is connected by a second line 23 and with intercalation of a second control valve 21 aswell as a rotating distributor 27 and a pump 25 to a stationary reservoir tank 26 for a disinfectant 3 which 1s at room temperature. The latter disinfectant consists of an aqueous solution of 4% disinfectant concentrate and 0.04% of a surfactant to improve wetting. This liquid disinfectant 3 is led by the pump 25 at an excess pressure of 2 bar to the mixing nozzles 2. The disinfectant contains as germicidal components 4000 ppm of H,O; and 2500 ppm of peracetic acid.

With the above-described installations of the injection machine 5 an atomized mixture of liquid disinfectant 3 and steam 4 1s blown into the interior of the bottles 1. To sterilize the exterior surface of the bottles 1 as well, after the input star 15, several mixing nozzles 2a are arranged in a stationary pattern and at a small distance laterally with respect to the path of movement of the bottles 1. These mixing nozzles 2a—with the exception of the rotating distributor 27 which 1s not required here—are connected in the same manner as the mixing nozzles 2 which move in a circular path with the rotating table by the lines 23 and the control valves 21 to the reservoir tank 26, and they are oriented honizontally. In addition, they are connected by lines 38 to a source of sterile pressurized air. :

The rinsing machine 6 according to Figures 1 and 5 in part has a similar structure to that of the injection machine 5 according to Figures 1-4. Identical parts are therefore denoted with the same reference numeral and the addition “a.” Here the elastic gripping tongs 13a can be pivoted about horizontal pivoting axles 28 by means of a cam control 29, as described in detail in European

Patent No. 721 808. For most of their circular movement with the rotating table 11, the bottles 1 are therefore inverted, that is their mouth opening is directed downward. In the area of the input star 15a and the output star 162, in contrast, they are in the upright normal position.

The treatment of the bottles 1 in the nnsing machine 6 occurs by means of the nozzles 30, which are arranged on the rotating table 11a, associated with the gripping tongs 13a, and which can be 4

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PCT/EP00/10611 8 inserted into the bottles 1. Each nozzle 30 is connected by one control valve 31, 32, 33 to a total of three ducts 34, 35, 36, in each case, which contain different rinsing media. In the : present case, these media are sterile air, sterile water and liquid disinfectant 3, preferably the same one as contained in the reservoir tank 26. The nozzle 30 is designed as a one- or multi-pipe nozzle, so that optionally different rinsing media can be introduced into the bottle 1.

The conveyor belt 7 connects the output star 16 of the injection machine 5 with the output worm 14a and the input worm 15a of the rinsing machine 6. Its length is such that in the case of the nominal performance of the device, the desired time of action of the disinfectant-steam mist introduced as a mist into the bottle in the injection machine 5 is achieved. During normal operation, the injection machine 5, the conveyor belt 7, and the rinsing machine 6 are driven synchronously with respect to each other, so that the result is a disturbance-free, continuous, transport of the bottles 1 from the input conveyor 8 to the output conveyor 9. The entire device is arranged in a chamber 37 drawn with a dot-dash line, which is supplied with sterile air of class 100. Thus any reinfection of the stenlized bottles 1 is prevented.

Using the above-described device, the sterilization process described below is carried out:

A bottle 1, delivered by a stretching-blowing machine which is not shown, is brought by the input conveyor 8, introduced into the cycle by the input worm 14, and transferred from the input star 15 to a gripping tong 13 of the injection machine 5. It is now located in the middle in the position indicated in Figures 2 and 3 under the mixing nozzle 2 which is associated with the gripping tong 13, which nozzle is at a distance of two to three centimeters from the mouth of the bottle. Then the two control valves 20 and 21 of the mixing nozzle 2 are synchronously opened for a period of 1.5 sec. In this process the mixing nozzle 2 receives, separately, from the reservoir tank 26, liquid disinfectant 3 having the already described composition, at room temperature and at an excess pressure of b2 bar, and, from the steam generator 24, steam at an excess pressure of 2 bar and at a temperature of 121°C. At the time of the exit from the ducts 18, 19 of the mixing nozzle 2, the two components are intensively mixed, resulting in a high energy mixed jet at a temperature of approximately 60-80°C and with an opening angle of approximately 20°. The mixed jet essentially contains a finely atomized disinfectant, steam, and 5

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" | PCT/EP00/10611 - optionally evaporated disinfectant and water droplets. As a result of the catalytically acting temperature increase or addition of heat, the disinfectant 3 is optimally activated.

The mixing nozzle 2 is arranged and designed in such a manner that the mixed jet which it generates penetrates essentially vertically downward through the mouth opening inté the interior of the bottle 1, and fills it completely. Since the bottle 1 is only at room temperature, most of the mixture condenses in the form of very fine droplets on the interior wall of the bottle and forms a closed, highly active, germicidal condensate film. The internal temperature of the bottle here increases to approximately 45°C due to the overall low heat content of the mixture which is sprayed in.

Moreover, as a result of the described process, the environmental air which is originally contained in the bottle 1 1s for the most part expelled out of the interior of the bottle. At the end of the 1.5 sec spraying time, the two control valves 20, 21 are synchronously closed. The described 1.5 sec of spraying time occupy the crosshatched rotating area of the rotating table 11, in Figure 1. This time penod is followed by a time of action lasting 3 sec, which is marked by the shaded area of the rotating table 11. Here the disinfectant 3 applied as a mist onto the internal wall of the bottle acts as a germicidal agent. The exterior area of the mouth of the bottle is also treated by the exiting mixture.

In the final phase of the rotating area of the bottle 1 with the rotating table 11, a 1.5 sec introduction of a spray consisting of a disinfectant-steam mixture again occurs through the same mixing nozzle 2. Here the interior of the bottle is heated to approximately 58°C. The critical temperature for PET bottles of approximately 65°C is thus not even approximated. The bottle 1 1s then grabbed by the output star 16 and the guide arch 17, and it is deposited on the conveyor 7.

Next there is a time of action which depends on the length of the conveyor belt 7, which can be varied depending on the type of the bottle, the desired sterilization effect and the desired disinfectant, and which is preferably in the range of 5-10 sec.

Due to the direct application onto the interior of the bottle by the mixing nozzle 2 and its exactly timed control, an exact dosage of the disinfectant 3 and the steam 4 which are introduced as a 6

REPLACEMENT SHEET af PCT/EP00/10611 g " is possible. Thus, for example, during the sterilization of a 1.5 L PET bottle with the described parameters and a mixing nozzle 2 having corresponding dimensions, during the 1.5 sec . of the phase of injection by spraying into the bottle 1, in each case 3.4 mL of disinfectant 3 and 1.4 g of steam 4 are injected through the nozzle. At a rate of 19,000 Fl/h, the resulting consumption per hour is 129.2 L of disinfectant 3 and 53.2 kg of steam 4. The achievable germicidal rates are 99.99-99.999%, depending on the types of test germs used. This satisfies all the requirements for the sterile filing of drinks into PET bottles.

In addition, there is optionally the consumption of 33 L per H of disinfectant 3 for the external sterilization of the bottles 1 through the nozzles 2a in the inlet area of the rotating table 11, by - means of which, if required, a reinfection of the interior of the bottle by germs on the exterior of the bottle can reliably be prevented.

At the end of the conveyor belt 7 the bottle 1, which carries on its interior and on its exterior, a film of disinfectant, 1s entered into the cycle by the input worm 14a, and transferred from the input star 15a in the upright position in a gripping tong 13a of the rinsing machine 6. Then the gripping tong 13a is pivoted, during the rotation of the rotating table 11a, through the control device 29 by 180°, so that the bottle 1 finally points downward with its opening. In this process, the nozzle 30 penetrated by a few millimeters into the mouth of the bottle (Figure 5). Now, by means of a corresponding control of the control valves 31, 32, 33, first, for a short time, liquid disinfectant is sprayed into the bottle 1 (cross-hatched area) and then the bottle 1 is alternately rinsed with sterile water and sterile air (shaded area) until the last residues of the disinfectant are almost completely removed from the bottle 1. The bottle is tilted back into the normal position, taken up by the output star 16a, and deposited on the output conveyor 9 in the upright normal position. By the latter conveyor it is transported to a sterile filling and closing machine, not shown, in an atmosphere which contains few or no germs, as exists in the chamber 37.

Instead of the conveyor belt 7, one or more transport stars can also be used to transport the bottles 1, in the appropriate distribution. As a result of this modular construction, the injection machine 5 and the rinsing machine 6 can be arranged immediately next to each other, taking up as little space as possible. It 1s also possible, to transfer the bottles 1 directly from the output star 7.

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) p PCT/EP00/10611 . 16a of the rinsing machine to the input star of the filling and closing machine. In this construction as well, appropriate dimensions of the transport star, can achieve the desired . treatment and action times. In particular in cases where the sterility requirements are low, it is also conceivable to provide the mixing nozzles 10 on a rotating table which rotates with the input star 15a of the rinsing machine 6, where the time of action is then shifted to the area“of the rotating table 11a. In all cases, the direct application onto the bottles 1 of the disinfectant-steam mixture exiting from the mixing nozzles 10 results in a low-consumption, reliable and reproducible sterilization treatment. 8

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Claims

: PCT/EP00/10611 q Claims

1. Method for the sterilization of packaging containers, where a heated disinfectant is generated using a nozzle, then it is led to the packaging containers and, after it has acted on the surface to be sterilized, it is again removed, characterized in that simultaneously a liquid disinfectant and steam are separately led to a mixing nozzle, in that a mixture of atomized and/or evaporated disinfectant and steam 1s formed by the mixing nozzle, and in that the mixed jet which exits from the mixing nozzle is aimed directly onto a packaging container.

2. Method according to Claim 1, characterized in that the mixing ration between the liquid disinfectant and the steam is approximately 2:1.

3. Method according to Claim 1 or 2, characterized in that the stearn which is led into the mixing nozzle is at a pressure of approximately 2 bar and at a temperature of approximately : 121°C.

4. Method according to one of Claims 1-3, characterized in that the disinfectant led into the mixing nozzle is at room temperature.

5. Method according to one of Claims 1-4, characterized in that the packaging containers are at room temperature before they are exposed to the mixed jet exiting from the mixing nozzle.

6. Method according to one of Claims 1-5, characterized in that the disinfectant which is led into the mixing nozzle consists of an aqueous solution of H,0,, peracetic acid and optionally a surfactant.

7. Method according to one of Claims 1-6, characterized in that the spraving time of the mixing nozzle per packaging container is one to two seconds. 9 REPLACEMENT SHEET a o PCT/EP00/10611 .

8. "Method according to one of Claims 1-7, characterized in that the time of action of the disinfectant-steam mist which condenses on the packaging container is approximately five to ten seconds.

9. Method according to one of Claims 1-8, characterized in that before the removal of the condensate which has condensed on the packaging container the packaging container is rinsed with a liquid disinfectant.

10. Method according to one of Claims 1-9, characterized in that the bottle and the mixing nozzle - associated with it are immobile with respect to each other while the disinfectant-steam mixture is blown onto the bottle.

11. Method according to Claim 1, characterized in that the bottle and the associated mixing nozzle together are continuously moved in a translation motion while the disinfectant-steam is blown onto the bottle.

12. Method according to one of Claims 1-11, characterized in that the mixed jet is blown directly through the mixing nozzle into the interior of the packaging container, preferably through its mouth opening.

13. Device for using the method according to Claim 1, with a conveyor for the packaging container to be sterilized and at least one nozzle, characterized in that at least one mixing nozzle (2) is aimed directly onto the packaging containers (1) transported by the convevor (11) and in that the mixing nozzle (2) is connecter by simultaneously opening control valves (20,21) to a steam generator (24) and a reservoir (26) for a liquid disinfectant (3).

14. Method according to Claim 13, characterized in that the mixing nozzle (2) is designed as a two-component atomization nozzle.

15. Device according to Claim 13 or 14, characterized in that the mixing nozzle (2) is aimed toward the mouth opening of a packaging container (1). i REPLACEMENT SHEET

9 PCT/EP00/10611 . 16. Device according to one of Claims 13-15, characterized in that the conveyor (11) transports the packaging container (1) in an upright position and in a horizontal direction, and in that the mixing nozzle (2) is directed vertically downward onto the packaging container (1).

17. Device according to Claim 18, characterized in that the conveyor (11) can be driven continuously and in that several mixing nozzles (2) are provided which move with the conveyor (11).

18. Device according to Claim 19, characterized in that the conveyor (11) is designed as a rotor which carries several holders (13) for the packaging containers (1) on the circumference and in that several mixing nozzles (2) are associated with the conveyor (11), at least one above each holder (13).

19. Device according to Claim 18, characterized in that the control valves (20, 21) which are associated with each mixing nozzle (2) are arranged on the conveyor (11) and connected with intercalation of a rotating distributor (27) and by lines (22, 23) to the steam generator (24) and the reservoir (26).

20. A method according to Claim 1, substantially as herein described and illustrated.

21. A device according to Claim 13, substantially as herein described and illustrated.

22. A new method of sterilization of containers, or a new device, substantially as herein described. 11 AMENDED SHEET