US3511592A

US3511592A - Device intended preferably for sterilizing web-like packaging materials

Info

Publication number: US3511592A
Application number: US570034A
Authority: US
Inventors: Alex Tuma
Original assignee: Tetra Pak AB
Current assignee: Tetra Pak AB
Priority date: 1965-08-10
Filing date: 1966-08-03
Publication date: 1970-05-12
Anticipated expiration: 1987-05-12
Also published as: CH462389A; DE1577633A1; GB1102635A; NL6611212A; DE1577633B2

Description

A. TUMA 3,511,592 DEVICE INTENDED PREFERABLY FOR STERILIZING WEBLIKE May 12, 1970 PACKAGING MATERIALS 2 Sheets-Sheet 1 Filed Aug. 5. 1966 INVENTOR ALEX TUMA BY Q JL W ATTORNEY May 12, 1970 A. TUMA 3,511,592 DEVICE INTENDED PREFERABLY FOR STERILIZING WEB-LIKE PACKAGING MATERIALS Filed Aug. 3, 1966 2 Sheets-Sheet 2 Fig. 2

INVENTOR ALEX T UM A BY f m; [Z W- ATTORNEY United States Patent US. Cl. 21-92 4 Claims ABSTRACT OF THE DISCLOSURE Apparatus to sterilize a web of packaging material having inner and outer containers which define a long narrow slot therebetween for the sterilizing liquid through which passes the web of material.

The present invention relates to a device for treating preferably web-like materials. More particularly, it relates to a device for sterilizing web-like packaging materials. The device comprises an outer container holding a certain quantity of processing liquid.

An object of the invention is to provide a device having small outer dimensions and holding a minimum of processing liquid but comprising a long processing path for the material to be moved through the device.

The device is characterized by an inner filling body having essentially the same shape as the outer container and intended to displace part of the processing liquid so that a long slot-shaped space filled with processing liquid is provided between the outer container and the filling body, in which the web material is meant to be advanced.

In the preferred embodiment the invention is further characterized in that the outer container has a considerable depth in relation to its other dimensions. At the sterilizing of material by means of the sterilizing liquid held in the outer container a considerably increased sterilizing elfect is obtained as a consequence of the static pressure in the lower portion of the outer container caused by the weight of the liquid.

Furthermore, the invention offers a possibility to heat the sterilizing liquid in a simple manner to a desired relatively high temperature, whereby the sterilizing effect is further intensified. This can be achieved by heating the filling body, whereby the said body due to the contact with the processing liquid is ableto heat the liquid and maintain it at the desired temperature.

Further objects and advantages of the invention will be apparent from the accompanying drawings showing a preferred embodiment, chosen by way of example, of the invention according to the application, and where FIG. 1 is a diagrammatic section of a sterilizing device in an operational position connected to a packaging machine, and

FIG. 2 shows the same device with its main parts separated from each other.

In the drawings, reference numeral 1 designates an outer container holding a relatively small volume of sterilizing liquid 3, preferably consisting of hydrogen peroxide H 0 of 35 percent, although other sterilizing liquids than H 0 may also be used. The outer container 1 is slightly wedge-shaped and has a considerable depth in relation to its width. The expression width designates the width of the device as shown in the drawings.

Furthermore the device comprises a filling body 2 which in the position of preparedness shown in FIG. 2 is located above the outer container 1 and in FIG. 1 inside the outer container 1. The filling body 2 consists of a hollow body filled with water 8. The water can be ice heated by means of a heating spiral 9. Reference numeral 14 designates connecting lines for the heating coil 9.

As mentioned, the device is intended for sterilizing a Web-like packaging material, the device being disposed in connection with a packaging machine designated 10 in FIG. 1. In the machine 10 the web-like packaging material 16, after being wound off from a storage roll 15 and being sterilized in the sterilizing device, is reshaped into a tube which is filled under aseptical conditions with the intended filling material and shaped into separate packages. In order to guarantee complete sterility it is necessary to keep the atmosphere in the packaging machine completely sterile. In order to achieve this there is maintained a certain pressure above atmospheric of sterile air inside the machine so that air containing microorganisms cannot penetrate into the machine from the surrounding atmosphere. However, there is still a risk for infection on account of the inlet opening of the packaging material in the machine. This is due to the fact that through the relatively large translation rate of the packaging material there is formed an air current parallel to the material. Under these conditions the rate of flow of the air may be so large that it will overcome the pressure inside the machine and will introduce microorganisms into the sterile atmosphere. In order to prevent this there is disposed a sleeve 11 through which the packaging material 16 is meant to be conducted into the machine 10. The sleeve 11 is of such a length that in the operational position of the sterilizing device (of FIG. 1) it is lowered with its inlet orifice 12 into the sterilizing liquid 3. This provides a liquid lock eifectively preventing the surrounding atmosphere from penetrating into the interior of the machine 10 through the inlet opening of the packaging material 16, and preventing the sterile gas from flowing out into the free air, which is of economical importance.

Other means shown in the drawings consist of a first pulley 4 journalled in holding means 5 which are connected with the outer container 1. There is further provided a second pulley 6, which is connected with the filling body 2 by holding means 7. Finally, reference numeral 13 designates a member for clamping fast the filling body 2. The said body 2 is consequently stationary, while the outer container 1 is displaceable between the positions shown in both drawings. The means for operating the outer container 1 have not, however, been shown in the drawings, which is not either necessary for understanding the principles of the invention. The device shown operates in a manner which will be described in the following. For this purpose it is assumed that the device originally occupies a position of preparedness, FIG. 2, in which connection the web of material 16 is led over the pulley 4, below the pulley 6 and moved up through the sleeve 11 into the machine 10. In the outer container 1 there is a small volume of hydrogen peroxide H 0 at room temperature. In a manufactured device the volume of H 0 is about 3.5 litres. The sterilizing liquid is then at the level designated 18. The water 8 located in the filling body 2 is heated to boiling temperature C. In the manufactured device the water volume amounts to about 10.5

itres.

When the machine 10 is to start the outer container 1 is moved upward toward the filling body 2 by means of members not shown in the drawings. By means of the pulley 6 the web of material 16 is pressed down against the bottom of the outer container 1 as a consequence of the relative motion 2 between the two

members

1 and 2. The filling body 2 displaces the liquid 3 so that along the greater part of the length of the device there only remains a narrow slot of liquid, in which slot the web of material 16 is meant to be advanced. As a consequence of the displacement the liquid 3 will occupy a higher level 17, which lies above the orifice 12 of the sleeve 11.

Due to the fact that the volume content of the filling body 2 is considerably larger than the quantity of sterilizing liquid 3, the latter 'willbe heated very quickly. This applies in particular to the liquid in the slot-shaped space between the outer vessel 1 and the filling body 2, which is heated, under the influence of the intimate contact with the hot filling body, essentially momentarily to a'temperature acceptable for obtaining a good sterilizing effect. In order to increase the sterilizing effect still further, the bath may of course be heated by means of the heating coil 9.

At the sterilizing operation the web of material 16 is fed from the storage roll 15, via the pulley 4 down into the sterilizing bath, below the lower pulley 6, up through the sterilizing bath and into the packing machine through the sleeve 11, which serves as a liquid lock.

During the passage through the liquid bath the web of material 16 is exposed to a combined chemical-thermal sterilizing operation. This combination has turned out to be more effective than a chemical and thermal sterilizing operation carried out separately. Due to the: fact that the device has a considerable depth, the sterilizing efiect increases still further. This is caused by the static pressure in the bottom portion of the device, which intensifies the contact between the microorganisms to be rendered harmless and the sterilizing liquid. In addition, as a result of the embodiment of the device a relatively long processing time is achieved, which in the present case amounts to about 12 seconds.

Because of the transport of the web of material 16 through the sterilizing bat-h there arises, of course, a certain flow of liquid. This consists on one hand of a current parallel to the web of material and on the other of a reflux from the right-hand side of the device to its left-hand side as seen in FIG. 1. However, there is no flow from the left to the right, which is important since this eliminates the risk that microorganisms will move through the sterilizing liquid the shortest path from the point where the web of material 16 is immersed into the bath up to the orifice 12 of the sleeve 11.

The position shown in FIG. 2 has been termed position of preparedness in the preceding text. A more adequate expression is material introducing position, for this position is only occupied when the packaging material is to be introduced into the machine. During breakdowns or when the sterilizing operation has to be stopped for other reasons it is suflicient to lower the outer vessel 1 only a relatively short distance, viz in such a way that the packaging material will be located completely above the liquid surface 18. Thereby the device can very quickly be returned to its operational position, i.e., the position shown in FIG. 1.

The device described above is shown with a stationary filling body and a mobile outer container. It wi l be realized, however, that it is also possible to make the outer container stationary and the filling body mobile and to make both means mobile in relation to each other.

It should be also possible to treat other materials than those in the nature of webs in the shown device. This may for instance be achieved by disposing the objects to be treated between two endless belts carrying the objects through the device.

Yet another modification is to use heated oil or another liquid in the container 2 instead of water. This makes it possible to obtain a considerably higher temperature of the body to be immersed into the sterilizing bat-h. It is also possible to use a completely stationary body having good heat-conductive properties.

Also other modifications of the device shown will be possible to achieve without exceeding the scope of the inventive idea. The invention is consequently not limited to the embodiment shown but is only limited by the subsequent claims.

That which is claimed is:

1. A device for sterilizing a Web of packaging material comprising: an outer elongated container adapted to hold a certain volume of processing liquid, an inner container of substantially the same shape as the outer container telescoped in said outer container and forming an elongated slot therebetween, said outer container and said inner container being displaceable relative to each other to vary the size of said slot.

2. A device intended preferably for sterilizing weblike packaging materials, comprising an outer wedgeshaped container holding a certain volume of processing liquid, characterized by an inner wedge-shaped filling body having essentially the same shape as the outer container and intended to displace part of the processing liquid so that a long space in the shape of a slot and filled with processing liquid is provided between the outer container and the filling body, in which the web-like material is meant to be advanced.

3; A device for sterilizing a web of packaging material comprising: an outer wedge-shaped elongated container "adapted to hold a certain volume of processing liquid, an inner Wedge-shaped container of substantially the same shape as the outer container telescoped in said outer container and forming an e ongated slot therebetween, said outer container and said inner container being disp1ace able relative to each other to vary the size of said slot.

4. The structure of claim 3 wherein said inner container has a pulley on the bottom end thereof.

References Cited UNITED STATES PATENTS 1,306,650 6/1919 Weinheim 118-429 XR 1,389,630 9/1921 Cooney 118-419 XR 2,168,997 8/1939 Lankes et a1. 118-419 3,163,971 1/1965 Loliger et a1. 21-2 XR 3,215,115 11/1965 Knight et a1. 118-429 XR 207,008 8/1878 Bryant 220-17 XR 232,026 9/ 1880 Hayward 220-17 MORRIS O. WOLK, Primary Examiner D. G. MILLMAN, Assistant Examiner U.S. Cl. X.R. 21-58, 99; 118-419