WO2021116014A1

WO2021116014A1 - Sterilizing spray method and sterilizing spray device for filling machine

Info

Publication number: WO2021116014A1
Application number: PCT/EP2020/084869
Authority: WO
Inventors: Yasuhiro Shinka; Hitoshi Matsumoto
Original assignee: Tetra Laval Holdings & Finance S.A.
Priority date: 2019-12-12
Filing date: 2020-12-07
Publication date: 2021-06-17
Also published as: JP2021091461A; JP6724229B1

Abstract

A sterilizing spray method which is used in a filling machine for producing packaging containers from a web-shaped packaging material having a joint for joining a terminal end of a first reel-shaped packaging material and a starting end of a second reel- shaped packaging material, wherein, after a tubular packaging material inside the filling machine has exited a sterile compartment and before the tubular packaging material is transversally sealed and cut, a sterilizing agent is sprayed using a spray device from a transverse direction towards a portion of the tubular packaging material including the joint at least on a side on which a longitudinal seal has been formed, and the concentration of the sterilizing agent at an outer circumferential portion of a spray pattern is higher than the concentration in a central portion. Bacteria which might enter from the minute gaps at the joint are killed by this means.

Description

[Title of the Invention] STERILIZING SPRAY METHOD AND STERILIZING SPRAY DEVICE FOR FILLING MACHINE

[Technical Field]

[0001]

The present invention relates to a sterilizing spray method and a sterilizing spray device which are used in a filling machine for the production of packaging containers for beverages or liquid foods, etc.

[Background Art]

[0002]

The production of packaging containers filled with a beverage or a liquid food, etc. using a filling machine conventionally involves deforming a web-shaped packaging material to form a tubular shape in the filling machine, forming a longitudinal seal, charging the beverage or the liquid food, forming a transverse seal, and cutting the packaging material into individual containers which are then moulded to produce final packaging containers.

[0003]

In the filling machine for producing the packaging containers, the web-shaped packaging material is set on a delivery unit while wound to a preset length in the form of a reel. The web-shaped packaging material is then fed out from the delivery unit and deformed into a tubular shape during the process, sealed in a longitudinal direction by means of a longitudinal sealing device, and the beverage or liquid food is charged. Following this, the tubular packaging material is sealed in a transverse direction and cut at predetermined intervals by means of a transverse sealing/cutting device, thereby forming pillow-shaped preliminary containers. The final shape is then moulded to form the packaging containers.

[0004]

In order for the filling machine to operate continuously, two packaging materials in the form of reels, namely first and second packaging materials, are set on the delivery unit, and the second-reel packaging material is continuously fed out following the first- reel packaging material. A terminal end of the first-reel packaging material and a starting end of the second-reel packaging material are therefore joined by means of a splicer so that the second-reel packaging material is fed out successively once the first-reel packaging material has been used up, and the packaging materials are continuously supplied to the filling machine without interruption.

[0005]

As shown in fig. 1, a preceding first-reel packaging material 11 and a succeeding second-reel packaging material 12 form a two-layer overlap at the location where the web-shaped packaging material reels are joined. The packaging material in a region including this two-layer overlap portion 13 is also deformed into a tubular shape inside the filling machine, and is finally moulded into a packaging container, but in this process, a longitudinal sealing portion 14 and a joint 15 forming a further overlap are present at the two-layer overlap portion 13 of the reel, and the packaging material forms four layers at the joint 15. The packaging material including this four-layer joint 15 cannot be sold on the market as a product, so packaging containers in which this four-layer joint 15 is present are removed from the production line. Packaging containers including a four-layer joint 15 are not sold on the market.

[0006]

As shown in fig. 1, however, minute gaps 16 may be formed at the four-layer joint 15 and bacteria may enter from these minute gaps 16 in places outside a region around a filling portion inside the filling machine which has been rendered a sterile environment (aseptic), so there are times when bacteria enter the tube which should essentially be a sterile environment, depending on conditions during production. In order to prevent this, an affiliated company of the present applicant has disclosed technology for preventing the ingress of bacteria from these minute gaps 16 by using a patch film to protect the four-layer joint 15 in advance, inside a chamber of the filling machine which is under a sterile environment (Patent Publication 1).

[0007]

Furthermore, instead of using a patch film to protect the four-layer joint 15, an affiliated company of the present applicant has disclosed technology for reinforcing a four-layer seal to prevent the ingress of bacteria from the minute gaps by further heating the longitudinal seal using an additional preheating means comprising a heating roller, a seam detection device, and a controller, etc., in order to further strengthen the four-layer seal (Patent Publication 2).

[0008]

Furthermore, one example of a sterilizing device for packaging materials that has been proposed relates to technology employing the sterilizing device to atomize a sterilizing agent such as a hydrogen peroxide aqueous solution by means of ultrasound, and causing the sterilizing agent to adhere to the packaging material with accompanying hot air so as to sterilize the surface of the packaging material (Patent Publication 3). [Prior Art Documents]

[Patent Publications]

[0009] [Patent Publication 1] JP 2008-296958 A [Patent Publication 2] JP 2011-140347 A [Patent Publication 3] JP 2006-36343 A [Summary of the Invention]

[Problems to be Solved by the Invention]

[0010]

Inside the filling machine, the web-shaped packaging material is moulded into a tubular shape (also referred to below simply as a “tube”), the longitudinal seal is formed, the filled tube is fed to outside a sterile compartment, and the transverse seal is formed, and at this time the interior of the tube is temporarily at a negative pressure so there is a possibility of air from outside the sterile environment being sucked in from the gaps at the four-layer joint. In the event that air has been sucked in, depending on the conditions during production, bacteria may propagate not only in packaging containers including the four-layer joint, but also inside tens of succeeding packaging containers, and there is a possibility that none of the packaging containers will be saleable as products.

[0011]

In order to solve this problem, a device for hermetically sealing the patch film needs to be provided inside the chamber in the prior art disclosed in Patent Publication 1, but there are problems in terms of constraints on the size and shape of the hermetic sealing device. Furthermore, there is also a problem in that it is difficult to clean the inside of the sterile compartment.

[0012]

Furthermore, in order to provide the additional preheating means inside the filling machine in the prior art disclosed in Patent Document 2, it is necessary to increase the size of part of the device around a filling pipe portion. There is also an additional problem in that periodic maintenance of the heating roller, etc. is required.

[0013]

Furthermore, when the prior art disclosed in Patent Publication 3 is used, it is possible to sterilize the surface of the packaging material, but it is difficult to thoroughly kill the bacteria entering from the minute gaps at the four-layer joint. That is to say, although it is possible to sterilize the surface of the packaging material, it is not possible to efficiently sterilize the minute gap portions which are at a transverse orientation in relation to the surface of the packaging material, and it is impossible to completely eliminate the ingress of bacteria present in the external air to the inside of tens of packaging containers which are subsequently produced.

The aim of the present invention lies in providing a sterilizing spray method for a packaging material, and a sterilizing spray device which solve the abovementioned problems, found for the first time by the present inventors.

[Means for Solving the Problems]

[0014]

A sterilizing spray method for a packaging container according to the present invention is used in a filling machine for producing packaging containers from a web- shaped packaging material having a joint for joining a terminal end of a first reel-shaped packaging material and a starting end of a second reel-shaped packaging material, and is characterized in that, after a tubular packaging material inside the filling machine has exited a sterile compartment and before the tubular packaging material is transversally sealed and cut, a sterilizing agent is sprayed using a spray device from a transverse direction towards a portion of the tubular packaging material including the joint at least on a side on which a longitudinal seal has been formed, and the concentration of the sterilizing agent at an outer circumferential portion of a spray pattern is higher than the concentration in a central portion.

[0015]

The present invention also provides a spray device for implementing the abovementioned sterilization method. The sterilizing spray device according to the present invention is externally fitted to a filling machine for producing packaging containers from a web-shaped packaging material having a joint for joining a terminal end of a first reel-shaped packaging material and a starting end of a second reel-shaped packaging material, and is characterized in that said sterilizing spray device comprises a two-fluid nozzle which is installed at a distance from the packaging material at a position between a sterile compartment inside the filling machine and a portion of the packaging material that is transversally sealed and cut, and which sprays a sterilizing agent from a transverse direction towards a portion of a tubular packaging material including the joint on a side which has been longitudinally sealed, and a liquid sterilizing solution on an outer circumferential side of the two-fluid nozzle is mixed with a supply of compressed air in the centre to form a spray pattern, the concentration at an outer circumferential portion of the spray pattern being higher than the concentration in a central portion. [0016]

Furthermore, the sterilizing agent spray pattern according to the present invention is such that the centre of the sterilizing agent spray pattern is directed towards an intersection of the longitudinal seal and the transverse seal and towards the longitudinal sealing portion above and below said intersection, and the diameter of the spray pattern is equal to or greater than the width of the packaging material. [0017]

Additionally, the sterilizing agent spray pattern according to the present invention is substantially circular.

[0018]

Furthermore, in the sterilizing spray method according to the present invention, a nozzle for spraying the sterilizing agent constitutes a two-fluid nozzle, and sprays the sterilizing agent in which a liquid sterilizing solution on an outer circumferential side of said two-fluid nozzle is mixed with a supply of compressed air in the centre thereof. [Advantage of the Invention]

[0019]

The present invention achieves an outstanding advantage in regard to a packaging container disinfection treatment in that it is possible to thoroughly prevent the ingress of bacteria from a four-layer longitudinal sealing portion. Furthermore, there is no need to incorporate a large device into a filling machine, and the spray device according to the present invention can be additionally installed at a distance from the filling machine, so there is also an advantage in that there are no constraints on the size or shape thereof. Furthermore, there is also an advantage in that maintenance of the filling machine and the spray device is simplified.

[Brief Description of the Drawings]

[0020]

[Fig. 1] (A) is a schematic diagram showing a portion where two packaging material reels are joined. (B) is a schematic diagram showing a longitudinal section of a longitudinal sealing portion in (A).

[Fig. 2] is an outline diagram showing the configuration of the filling machine for producing packaging containers and a process of producing the packaging containers, in accordance with a mode of embodiment of the present invention.

[Fig. 3] (A) is a schematic diagram showing the structure of a spray device tip end portion in accordance with a mode of embodiment of the present invention. (B) schematically shows a spray pattern according to the present invention.

[Fig. 4] (A) is a schematic diagram showing a horizontally-long elliptical spray pattern on the packaging material. (B) is a schematic diagram showing a vertically-long elliptical spray pattern on the packaging material. (C) is a schematic diagram showing a circular spray pattern with a varying concentration according to the present invention, on the packaging material.

[Fig. 5] (A) is a schematic diagram in cross section showing a general method of use of a two-fluid nozzle. (B) is a schematic diagram in cross section showing a usage method of a two-fluid nozzle according to the present invention.

[Mode for Implementing the Invention]

[0021]

Fig. 2 shows an outline diagram of a filling machine 100 for implementing the present invention, showing the flow of a web-shaped packaging material when such a material is used. The packaging material is set on a delivery unit 110 while wound to a preset length in the form of a reel, and a web-shaped packaging material 101 is fed out from the delivery unit 110. In order for the filling machine to operate continuously, it is configured in such a way that a current reel 102 (first reel) is set on the delivery unit, and a separate, succeeding reel (second reel; not depicted) is set adjacent to the current reel 102, and when the packaging material thereon has all been fed out, a terminal end of the packaging material on the first reel 102 and a starting end of the packaging material on the following reel are joined and connected by means of a splicer (not depicted) so that the packaging material on the following reel is continuously fed out once the packaging material on the current reel 102 has been used up.

[0022]

When the packaging material 101 has been fed out from the delivery unit 110, a sealing tape is supplied to an edge portion of the packaging material 101 by means of a sealing tape affixing device 105 part way along. The whole surface of the packaging material 101 is then sterilized by passing through a sterilizing tank 112 containing a sterilizing solution such as hydrogen peroxide, after which the packaging material is dried by means of an air knife 114 and fed to a sterile compartment 120. Inside the sterile compartment 120, the web-shaped packaging material 101 is then gradually deformed by means of an upper forming ring and another forming ring so as to be moulded into a tubular shape. The tubular packaging material is then filled with a beverage or liquid food through a filling pipe 122. Longitudinal sealing is then performed, and at this time, a pressure roller (not depicted) is rotatably arranged on an inner side of a tube 124, and a counter roller (not depicted) which is subjected to pressure from the opposing pressure roller in order to press and support the packaging material is rotatably arranged on an outer side of the tube 124, in such a way as to pinch one edge portion and another edge portion of the tubular packaging material. As the tube 124 travels, the pressure roller and the counter roller rotate while the edge portions of the packaging material are pressed in a pinched state, mating surfaces of a longitudinal sealing portion are heated by a preliminary heating means 126, and pressure and bonding are applied to complete the longitudinal seal.

[0023] A sterilizing agent is sprayed from a transverse direction by means of a spray device 130 at a four-layer joint 15 of the tube 124 which has exited the sterile compartment 120 after longitudinal sealing, the spraying being performed at a timing at which the four-layer joint 15 passes through support rollers 128. A sterilization process performed by the spray device 130 will be described in detail later. Transverse sealing and cutting are then performed at predetermined intervals by means of a transverse sealing/cutting device (jaw system) 140, to form pillow-shaped preliminary containers 152. The pillow-shaped preliminary containers 152 are further moulded into a predetermined final shape to complete packaging containers 154. The pillow-shaped preliminary containers 152 including the four-layer joint 15 are removed from the production line before being moulded into the final shape, or the packaging containers 154 including the four-layer joint 15 are removed from the production line after having been moulded into the final shape.

[0024]

As described above, packaging materials including a location where reels are joined such as shown in fig. 1 enter the filling machine in this process, and bacteria may penetrate from minute gaps 16 at the stage of exit from the sterile compartment 120, so there is a possibility of bacteria entering the tube which should essentially be a sterile environment. In order to prevent this in accordance with the present invention, a process of spraying a sterilizing agent at the four-layer joint 15 has been introduced to prevent the ingress of bacteria by re-sterilizing that portion. The configuration and method therein will be described below.

[Exemplary Embodiment]

[0025]

Fig. 3(A) schematically shows a tip end section of the spray device used in an exemplary embodiment of the present invention. The tip end portion of the spray device comprises a two-fluid nozzle, and a liquid sterilizing solution on an outer circumferential side of the two-fluid nozzle is mixed with a supply of compressed air in the centre to form a spray pattern. The sterilizing agent is jetted from the tip end of the nozzle in a conical spray pattern and is sprayed at the four-layer joint 15 of the packaging material. As shown in fig. 3(B), the sterilizing agent spray pattern according to the present invention has a higher concentration at an outer circumferential portion than in a central portion. As shown by 130 in fig. 2, the spray device is arranged a predetermined distance away from the tube on the longitudinal sealing side of the tube, after the packaging material has exited the sterile compartment 120 in which the pressure roller is present, and above the transverse sealing device 140. [0026]

The tubular packaging material 124 travels continuously from above to below, and, assuming that the time at which the four-layer joint 15 arrives at a central position of the spray pattern is the middle of the spray timing, the timing at which spraying is performed is therefore set for a period of 30 seconds before the middle and a period of 10 seconds after the middle, making a total of 40 seconds. This timing is determined by pre calculating the period of time elapsed from the time of splicing until the time of spraying, based on the distance travelled during that time and the speed of the packaging material. However, the determination of the timing is not limited to this method, and an optical sensor or the like may be arranged on an upper portion of the spray device and spraying may be performed once an accurate position of the joint 15 has been detected.

[0027]

As a result of various experiments, it was found that the efficacy of sterilization depends greatly on the position on the packaging material being sprayed, and on the shape of the spray (spray pattern) on the packaging material surface and the size thereof. The results thereof will be described in detail below.

[0028]

(Effect of spray position)

It was understood that the greatest effect in terms of the position on the packaging material being sprayed is achieved when the centre of the spray pattern is aligned with the four-layer joint 15 of the packaging material. An increase in the degree of contamination was confirmed when the spray pattern was offset to the upper side of the joint.

[0029]

(Effect of spray pattern)

Experiments were carried out using various shapes of sterilizing agent spray patterns. Fig. 4 schematically shows specific spray patterns (the grey sections) on the packaging material. A horizontally-long elliptical pattern is shown in fig. 4(A), a vertically-long elliptical pattern is shown in fig. 4(B), and a substantially circular spray pattern with a varying concentration is shown in fig. 4(C). The pattern in fig. 4(C) is a substantially circular pattern in which the concentration of the sterilizing solution in an outer circumferential region such as shown in fig. 3(B) is increased and the concentration in an inside region is reduced. The drawings schematically show two types of grey indications, namely a dark grey indication in an outer circumferential high-concentration region, and a light grey indication in a low-concentration region, but in actual fact the concentration varies gradually from high to low. In contrast to this, the concentrations are almost uniform over the whole pattern in fig. 4(A) and fig. 4(B), and the only differences lie in the fact that the concentration is high in the central portion and the directions of the major axes of the elliptical shapes are different.

[0030]

Using the patterns in each of fig. 4(A)-(C), the joints of packaging containers were sterilized using hypochlorous acid and sterile air as a sterilizing agent, and repeated experiments were carried out as to whether the inside of the packaging containers was contaminated with bacteria. The amount of sterilizing solution jetted was 1.5 (L/min), the air pressure was 0.1 (MPa), and the pressure of the sterilizing solution was 0.2 (MPa), and the distance between the nozzle tip end and the packaging container was 30 (cm). The results are shown in table 1. Although a constant effect was apparent in both fig. 4(A) and fig. 4(B) with elliptical shapes having a uniform concentration, there were times when contamination occurred and it was understood that the sterilizing effect was inadequate. In contrast to this, in fig. 4(C) having the substantially circular pattern with a varying concentration according to the present invention, bacterial contamination occurred zero times out of six experiments, and the sterilizing effect was clearly very high. Furthermore, when the amount of sterilizing agent jetted was changed from 1.5 (L/min) to 0.5 (L/min), it was understood that an even greater sterilizing effect could be achieved.

[0031]

[Table 1]

Results of bacterial contamination on the inside of packaging containers according to spray patterns (A)-(C)

(Effect of size of spray pattern)

The sterilization properties were most outstanding when the size of the outer diameter of the spray pattern according to the present invention was at least equal to or greater than the width of the tubular packaging material, and was preferably a size overlapping as far as the support rollers, with spraying being performed while the centre of the spray was directed at an intersection of the longitudinal seal and the transverse seal (the four-1 ay er j oint) .

[0032]

(Structure of the spray nozzle)

The structure of the spray nozzle for forming the substantially circular pattern with a varying concentration will be described below. The present invention employs a two-fluid nozzle of the internal air and external mixing type. Fig. 5 schematically shows a cross section thereof. As shown in fig. 5(A), a conventional nozzle has two concentric circular openings, with the sterilizing solution being supplied for use in the central portion and compressed air being supplied for use on the outer circumferential portion, but according to the present invention, as shown in fig. 5(B), compressed air is supplied to the central portion and the sterilizing solution is supplied to the outer circumferential portion, and the compressed air and the sterilizing solution are mixed outside the nozzle to form an atomized sterilizing agent. By this means, a full-cone spray shape is formed, and the spray pattern which is achieved on an irradiation surface is substantially circular with a varying concentration such that the concentration at the outer peripheral portion is higher than that in the central portion, as shown in fig. 4(C). In contrast to this, the spray pattern achieved in the conventional drawing (A) is substantially circular with a substantially uniform concentration or a high concentration in the central portion. The uniform-concentration elliptical patterns in the comparative examples of fig. 4 (A) and (B) are obtained by employing a nozzle having slit openings rather than circular openings. [0033]

There is no major restriction to the angle of jetting of the spray nozzle, but according to this exemplary embodiment, spraying was performed at a downward angle of approximately 35° from a horizontal plane, in order to avoid members which should not be sprayed with a liquid (e.g., a photoelectric tube) at the upper portion of the spray nozzle. However, if this angle is excessively large, then the spray pattern becomes offset from a circular shape, which is therefore undesirable.

[0034]

The present invention was described above with reference to an exemplary embodiment, but the present invention is not limited to the abovementioned mode of embodiment. Various improvements or design modifications may be made to the present invention within a scope that does not depart from the essential point of the present invention based on the knowledge of a person skilled in the art, and the present invention also includes any of the various improvements or design modifications.

[0035] Furthermore, the abovementioned mode of embodiment is not limiting, and the present invention can also be applied to packaging containers formed by means of packaging materials of any form. Furthermore, the present invention can also be applied to packaging containers filled with any type of beverage, liquid food or food powder, etc. [0036]

Furthermore, the content disclosed in Patent Documents 1 and 2 which are patent applications by an affiliated company of the applicant of this case are cited herein in regard to general concepts outside the characterizing sections of the invention of this application.

[Key to Symbols]

[0037]

11 Preceding packaging material

12 Succeeding packaging material

13 Joint of reel

14 Longitudinal sealing portion

15 Four-layer joint

16 Gap

100 Filling machine

101 Packaging material

102 Reel

110 Delivery unit

114 Air knife

120 Sterile compartment

122 Filling pipe

124 Tube

130 Spray device

140 Transverse sealing/cutting device

152 Preliminary container

154 Packaging container

Claims

CLAIMS [Claim 1]

Sterilizing spray method which is used in a filling machine for producing packaging containers from a web-shaped packaging material having a joint for joining a terminal end of a first reel-shaped packaging material and a starting end of a second reel shaped packaging material, wherein, after a tubular packaging material inside the filling machine has exited a sterile compartment and before the tubular packaging material is transversally sealed and cut, a sterilizing agent is sprayed using a spray device from a transverse direction towards a portion of the tubular packaging material including the joint at least on a side on which a longitudinal seal has been formed, and the concentration of the sterilizing agent at an outer circumferential portion of a spray pattern is higher than the concentration in a central portion.

[Claim 2]

Sterilizing spray method according to Claim 1, wherein the centre of the spray pattern is directed towards an intersection of the longitudinal seal and the transverse seal and towards the longitudinal sealing portion above and below said intersection, and the diameter of the spray pattern is equal to or greater than the width of the packaging material .

[Claim 3]

Sterilizing spray method according to Claim 1 or 2, wherein the spray pattern is substantially circular.

[Claim 4]

Sterilizing spray method according to any one of Claims 1 to 3, wherein a nozzle of the spray device for spraying the sterilizing agent constitutes a two-fluid nozzle, and sprays the sterilizing agent in which a liquid sterilizing solution on an outer circumferential side of said two-fluid nozzle is mixed with a supply of compressed air in the centre thereof.

[Claim 5]

Sterilizing spray device externally fitted to a filling machine for producing packaging containers from a web-shaped packaging material having a joint for joining a terminal end of a first reel-shaped packaging material and a starting end of a second reel shaped packaging material, wherein said sterilizing spray device comprises a two-fluid nozzle which is installed at a distance from the packaging material at a position between a sterile compartment inside the filling machine and a portion of the packaging material that is transversally sealed and cut, and which sprays a sterilizing agent from a transverse direction towards a portion of a tubular packaging material including the joint on a side which has been longitudinally sealed, and a liquid sterilizing solution on an outer circumferential side of the two-fluid nozzle is mixed with a supply of compressed air in the centre to form a spray pattern, the concentration at an outer circumferential portion of the spray pattern being higher than the concentration in a central portion.

[Claim 6]

Sterilizing spray device according to Claim 5, wherein the centre of the spray pattern is directed towards an intersection of the longitudinal seal and the transverse seal and towards the longitudinal sealing portion above and below said intersection, and the diameter of the spray pattern is equal to or greater than the width of the packaging material.