WO2015044512A1

WO2015044512A1 - Ultrasonic defoaming apparatus for a packaging machine and a packaging machine

Info

Publication number: WO2015044512A1
Application number: PCT/FI2014/050685
Authority: WO
Inventors: Juha Lehtioksa; Mika Peltola
Original assignee: Lamican Oy
Priority date: 2013-09-26
Filing date: 2014-09-09
Publication date: 2015-04-02
Also published as: EP3049330A1; FI125193B; FI20135964A

Abstract

The invention relates to an ultrasonic defoaming apparatus (10) for an aseptic liquid container packaging machine (50) comprising an ultrasonic hammer (12), an ultrasonic amplifier (14) and an ultrasonic crystal (16). The ultrasonic amplifier (14) is fastened to the packaging machine outside an aseptic chamber (51) and the ultrasonic hammer (12) is arranged within the aseptic chamber (51) of the packaging machine (50) above the container conveyor. The ultrasonic hammer is configured to direct ultrasonic oscillation towards containers on the container conveyor for defoaming the foam of containers.

Description

ULTRASONIC DEFOAMING APPARATUS FOR A PACKAGING MACHINE

AND A PACKAGING MACHINE

Field of the invention The present invention relates to an ultrasonic defoaming apparatus to be used in packaging machines especially in aseptic packaging circumstances of liquid containers.

Furthermore, the invention relates to an aseptic liquid container packaging machine comprising at least one ultrasonic defoaming apparatuses for defoaming foam from liquid containers especially in aseptic circumstances by ultrasonic radiation.

Background

Packaging machines produce thousands of sealed liquid containers per hour by forming, filling and sealing those containers. However, when containers are filled with liquids such as milk, fruit juices or any other foamable liquid, foam may be formed above the liquid level of containers. This foam has to be removed before closing the container by sealing. There exist methods and devices for eliminating the foam above the level of a liquid, and particularly above the liquid content of a container filled with foamable liquid. Foam can be removed, for example, by a suction pipe that removes the foam from the level of a liquid by sucking it to a tank. Alternatively, the foam can be removed by an elimination method and apparatus, wherein foam is collapsed by the application of high frequency wave radiation, which method and apparatus are disclosed in publication US4295502. In US4295502, individual sonotrodes are distributed over the underside of an aluminum block in such a way that they approximately cover the cross- sectional area of a container both lengthwise and widthwise.

Summary Now there has been invented an improved ultrasonic defoaming apparatus to be used in packaging machines to overcome drawbacks of the existing foaming apparatus and to present a novel ultrasonic defoaming apparatus especially for aseptic liquid container packaging machines. The ultrasonic defoaming apparatus according to the invention is characterized in what will be presented in the independent claim 1. The ultrasonic defoaming apparatus comprises an ultrasonic hammer, an ultrasonic amplifier and an ultrasonic crystal. The ultrasonic amplifier is fixed between the ultrasonic hammer and the ultrasonic crystal and fastened to the packaging machine outside an aseptic chamber of the packaging machine. Whereas, the ultrasonic hammer is arranged within the aseptic chamber above a container conveyor that is also arranged within the aseptic chamber. The ultrasonic hammer is configured to direct ultrasonic oscillation towards at least one container on the container conveyor for defoaming the foam of said at least one container. The invention also relates to an aseptic liquid container packaging machine comprising at least one above mentioned ultrasonic defoaming apparatus and to a method for defoaming an aseptic container by an ultrasonic defoaming apparatus in an aseptic liquid container packaging machine. The invention provides significant advantages to prior art, for example, because foam can be defoamed in aseptic circumstances by effective apparatus without contaminating micro-organisms. In addition, by an embodiment of the invention several containers can be defoamed at the same time. There may also be two or more ultrasonic defoaming apparatuses in parallel inside an aseptic chamber of the aseptic chamber of the packaging machine. Further, the ultrasonic defoaming apparatus can be effectively sterilized and its structure and material also enable effective sterilization of an aseptic liquid container packaging machine.

Description of the Drawings

In the following, various embodiments of the invention will be described in more detail with reference to the appended drawings, in which shows an ultrasonic defoaming apparatus according to an embodiment of the invention;

Fig. 2 shows an ultrasonic defoaming apparatus according to an embodiment of the invention in a cross-sectional profile;

Fig. 3 shows obliquely two parallel ultrasonic defoaming apparatuses according to an embodiment of the invention;

Fig. 4 shows two parallel ultrasonic defoaming apparatuses above a line of containers on a container conveyor of the packaging machine according to an embodiment of the invention; and

Fig. 5 shows a part of an aseptic liquid container packaging machine according to an embodiment of the invention.

Description of Example Embodiments In many cases, aseptic packaging processes are needed for liquid containers in order to produce a product that guarantees optimal sterility assurance level, complies with the latest regulatory requirements and fulfills food legislation. This kind of aseptic process allows products to retain color, texture, natural taste and nutritional value longer without preservatives or refrigeration. However, these aseptic packaging circumstances of aseptic packaging process define tight requirements for the packaging machine and packaging technology. The product that fulfils hygiene requirements has to be sterilized, filled and sealed in the aseptic environment. In addition, the environment, where product is filled and sealed must also be sterilized i.e. free of potentially contaminating micro-organisms. The product, for example, a sealed liquid container that is produced in aseptic packaging circumstances, may be called an aseptic liquid container. In aseptic process, a container i.e. a package is sterilized and then filled and sealed under sterilized atmosphere. This means that the container must be sterile prior to filling and during the filling and sealing. Sterilization of the container may be achieved, for example, by using hot air and steam or by combining heat treatment with hydrogen peroxide chemical sterilization, wherein hydrogen peroxide is eliminated from the packaging material using pressure rollers or hot air. It is advantageous to sterilize the container through an unsealed bottom of the container, because through the unsealed bottom all inner surfaces can be more efficiently sterilized compared to a situation where sterilization is done through an opening on the lid of the container. The opening on the lid of the container may be, for example, a small beverage aperture.

In addition, the use of the unsealed bottom of the container gives more advantages. When the container is filled through the unsealed bottom of the container, a bigger feeding pipe may be used again due to the bigger filling opening. Bigger feeding pipes may enable faster filling of the container and further bigger feeding pipes ensure that solid material of the liquid, such as, fruit flesh, ends up in the container instead of wall of the feeding pipe as a blockage, which might be a case with smaller feeding pipes. Bigger feeding pipes may also enable more accurate filling so that exact amount of liquid ends up in the container instead of the lid or surrounding the container, because bigger feeding pipes has smaller flow rate and thus smaller amount of splashes are caused.

There exist some liquids which especially need aseptic packaging circumstances to ensure adequate preservability. These liquids may be, for example, protein beverages, cream, milk-based beverages such as cacao, fruit juices or other beverage having pH level under 4.6. These above mentioned liquids are often very foamable and when the container is filled through the unsealed bottom of the container, foam may be formed above the liquid level of containers. Formed foam has to be removed, eliminated, before closing the container by sealing to ensure tight and impermeable seal. It is possible to remove the foam from the level of a liquid, for example, by sucking it to a tank by a suction pipe. However, the suction pipe is not in all cases suitable to be used for foam elimination in an aseptic chamber of the aseptic process, because the suction pipe is connected to a tank whereto the foam is sucked and the tank is outside the aseptic chamber. Therefore, the suction pipe is not an aseptic solution because it has that direct connection outside the aseptic chamber to the non-aseptic space. And even if the pipe has low pressure compared to the tank, the intensity of the low pressure might be unstable as a function of time. During a low intensity period contaminants may enter the aseptic chamber from the tank. In addition, suction of the foam cannot be switched off in the aseptic chamber, because the switching off removes the pressure difference and again contaminants may enter the aseptic chamber. Further, the suction pipe may remove too much liquid in addition to foam so that the liquid container does not fulfil a degree of filling.

In addition, it is possible to remove the foam from the level of a liquid, for example, by an existing apparatus that collapses foam by ultrasonic wave radiation. The ultrasonic wave radiation is produced by individual sonotrodes which are distributed over the underside of the aluminum block in such a way that they approximately cover the cross-sectional area of one container. This existing solution is also not so usable in aseptic chambers, because its structure is very complicated to sterilize due to cantilever sonotrodes. In addition, it is also complicated because the aluminum block is not durable enough, for example, for alkaline washing, such as lye washing. Alkaline washing is needed for cleaning the chamber before sterilization so that an aseptic environment for packaging can be ensured. In addition, it is possible that the existing structure cannot be fastened to a packaging machine so that the device producing the ultrasonic wave radiation stays only in the aseptic chamber without moving in and out of an aseptic chamber.

In the following, the invention will be described in more detail by using, as an example, an ultrasonic defoaming apparatus 10 according to the embodiment shown in Fig. 1. The ultrasonic defoaming apparatus 10 is suitable to be used in aseptic liquid container packaging machines, but also in non-aseptic liquid container packaging machines, if aseptic circumstances are not needed. The ultrasonic defoaming apparatus 10 may be used for defoaming i.e. eliminating foam on liquid product in the container. In many cases foam is formed above the liquid level of containers during the filling of the container.

Figure 1 shows the ultrasonic defoaming apparatus 10 comprising an ultrasonic hammer 12, an ultrasonic amplifier 14 and an ultrasonic crystal 16, wherein the ultrasonic amplifier 14 is fixed between the ultrasonic hammer 12 and ultrasonic crystal 16. The ultrasonic amplifier 14 is fastened outside the aseptic chamber of the packaging machine (a part of the packaging machine is shown in figure 5) so that the ultrasonic hammer 12 is located within the aseptic chamber above the container conveyor. The ultrasonic amplifier 14 is fastened to the packaging machine by fastening means, for example, by screws from the zero point of the ultrasonic waves produced by the ultrasonic crystal 16. The ultrasonic amplifier 14 and ultrasonic crystal 16 are outside the aseptic chamber. In the aseptic chamber, the ultrasonic hammer 12 is configured to direct ultrasonic oscillation towards at least one container on the conveyor for defoaming the foam above the liquid level.

The ultrasonic hammer 12 may be made of titanium that fulfils the environmental requirements such as cleanability and sterilizability of an aseptic chamber. Titanium is suitable both for acid washing and for alkaline washing, such as, lye washing so that the ultrasonic hammer 12 that is the only part of the ultrasonic defoaming apparatus 10 located in the aseptic chamber (shown in figure 5) can be sterilized while sterilizing the aseptic chamber by the acid washing and/or alkaline washing. However, the ultrasonic hammer 12 may also be made of some other material that fulfils the environmental requirements, for example, of stainless steel. Figure 2 shows an ultrasonic defoaming apparatus 20 according to an embodiment of the invention in a cross-sectional profile. The ultrasonic defoaming apparatus 20 is fixed to a packaging machine 22 from an ultrasonic amplifier 24. In this embodiment, fixing is executed by screws 25, but it is also possible to use some other fixing means. In figure 2 is also shown an area 27 where an ultrasonic hammer 26 is connectable to the ultrasonic amplifier 24.

Figure 3 shows obliquely two parallel ultrasonic defoaming apparatuses 30, 31 according to an embodiment of the invention. Ultrasonic defoaming apparatuses 30, 31 are arranged in parallel so that foam from several containers (in one container line) can be defoamed simultaneously by ultrasonic hammers 32, 33. Ultrasonic hammers 32, 33 direct ultrasonic oscillation towards a line of container/s on a container conveyor underneath the hammers 32, 33 for defoaming the foam of the container/s. In the container conveyor, multiple containers travel as lines. Each operation i.e. sterilizing, filling, defoaming and sealing is done at the same time for each container of one line.

Figure 4 shows two parallel ultrasonic defoaming apparatuses 40, 41 above a line of containers on a container conveyor 42 according to an embodiment of the invention. In this embodiment, the line of a container conveyor 42 comprises six parallel containers, three for both hammers 45, 46. The ultrasonic hammers 45, 46 are both configured to direct ultrasonic oscillation towards three containers on the container conveyor simultaneously for defoaming the foam of said containers inside the aseptic chamber. The number of containers in one line can vary, for example, from 1 to 10. Movement direction of the container line 42 is marked by an arrow 44. Container lines adjacent to the container line 42 are not shown. The ultrasonic hammers 45, 46 have an elongated shape and the elongated side of the ultrasonic hammers 45, 46 are arranged transversely to the container conveyor and paralleled to the line of the container conveyor 42.

The container line 42 (and also containers) may hold still while defoaming underneath the ultrasonic hammers 45, 46 or they may move while defoaming. An exposure time is the time that the ultrasonic hammers 45, 46 use for directing ultrasonic oscillation towards foam structures of containers underneath the hammers 45, 46 for defoaming the foam of the containers. The length of exposure time may depend on a case, but the length of exposure time may be, for example, 0.6 s. Height i.e. distance between hammers 45, 46 and the liquid level inside the container may be, for example, 20-35 mm. After ultrasonic hammers 45, 46 have radiated the foam for selected exposure time from a suitable distance, the foam will be completely destroyed above the content (liquid) of containers and the containers are suitable to be sealed. However, it is possible that there are some liquids needing longer or shorter exposure time and/or distance.

The vibration frequency of ultrasonic defoaming apparatuses i.e. the ultrasonic oscillation may be, for example, 20 kHz and suitable ultrasonic power may be, for example, 3 kW.

Figure 5 shows a part of an aseptic liquid container packaging machine 50 according to an embodiment of the invention. The packaging machine 50 comprises an aseptic chamber 51 and two ultrasonic defoaming apparatuses 53, 54 with ultrasonic hammers 52. Dosing nozzles 55 of the packaging machine 50 are arranged to fill container with liquids and while filling foam may be formed above the liquid level of containers. Only part of dosing nozzles 55 are shown in figure 5. Ultrasonic hammers 52 of the ultrasonic defoaming apparatuses 53, 54 are configured to direct ultrasonic oscillation towards containers on the container conveyor for defoaming the foam of containers inside the aseptic chamber 51.

In addition, there has been invented an aseptic liquid container packaging machine comprising at least one ultrasonic defoaming apparatus according to an embodiment of the invention and for defoaming foam in aseptic environment of aseptic packaging process by at least one ultrasonic defoaming apparatus. It is obvious that the present invention is not limited solely to the above- presented embodiments, but it can be modified within the scope of the appended claims.

Claims

Claims:

1. An ultrasonic defoaming apparatus for an aseptic liquid container packaging machine, wherein the ultrasonic defoaming apparatus (10) comprises an ultrasonic hammer (12), an ultrasonic amplifier (14) and an ultrasonic crystal (16), wherein the ultrasonic amplifier (14) is fixed between the ultrasonic hammer (12) and the ultrasonic crystal (16) and fastened to the packaging machine (50) outside an aseptic chamber (51 ) of the packaging machine (50), wherein the ultrasonic hammer (12) is arranged within the aseptic chamber (51 ) of the packaging machine (50) above the container conveyor of the packaging machine (50) and wherein the ultrasonic hammer (12) is configured to direct ultrasonic oscillation towards at least one container on the container conveyor for defoaming the foam of said at least one container.

2. An ultrasonic defoaming apparatus according to claim 1 , wherein the ultrasonic hammer (12) is arranged in the vicinity of the unsealed bottom of said at least one container when directing ultrasonic oscillation towards at least one container.

3. An ultrasonic defoaming apparatus according to claim 2, wherein the ultrasonic hammer (12) has an elongated shape and the elongated side of the ultrasonic hammer is arranged transversely to said container conveyor.

4. An ultrasonic defoaming apparatus according to any of the claims 1 to 3, wherein the container is holding still while defoaming.

5. An ultrasonic defoaming apparatus according to any of the claims 1 to 3, wherein the container is moving while defoaming.

6. An ultrasonic defoaming apparatus according to any of the claims 1 to 5, wherein the ultrasonic hammer (12) is configured to direct ultrasonic oscillation towards three containers on the container conveyor simultaneously for defoaming the foam of said containers inside the aseptic chamber (51 ).

7. An ultrasonic defoaming apparatus according to any of the claims 1 to 6, wherein the ultrasonic hammer (12) is made of titanium.

8. An ultrasonic defoaming apparatus according to any of the claims 1 to 6, wherein the ultrasonic amplifier (14) is arranged to be fixed to the aseptic liquid container packaging machine (50) outside the aseptic chamber (51 ).

9. An aseptic liquid container packaging machine comprising at least one ultrasonic defoaming apparatus (10) according to any of the claims 1 to 8.

10. An aseptic liquid container packaging machine according to claim 9, wherein the packing machine (50) comprises two ultrasonic defoaming apparatuses (52) in parallel above the container conveyor of the packaging machine (50).