US 3020120 A
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Description (OCR text may contain errors)
W. LijLlGER Feb. 6, 1962 METHOD AND MEANS FOR STERILIZING STRIPLIKE MATERIAL Filed Feb. 17, 1958 IN V EN TOR.
O m a W M A ".u L N s,02a,120. Mamet) Ann MEANS FOR srERrrIzlNo STRHEPLHKE MATERIAL Willi Liilig'er, Grunegg, Konolfingen, Switzerland, as-j.
signer 'to Alpura Aktie'ngeseiischaft, Bern, Switzerland,
acorporation of iiwitzerland Filed Felt. 17, 1958,- Ser. No. 715,:557 Claims priority, applicationlswitzerland :Feh.w2i),1957 Ciaimsc (Ci. 214 l) to the bottles. The relative high cost of cans and-the excessive weight of bottles as well as the costs connected with returning and cleaning the bottles prohibit the use of this type of containers at least for consumer goods, as milk. Moreover, glasses usedfonmaking bottles for these purposes do not sustainrepeated heating .up to the sterilization temperature of about 250 C. and higher.
Packings and containersare known which are made of a material which consistsat least in part oforganic substances, for example, synthetic materials as polyethyh.
ene orpaper which carries at least on one side layer of a synthetic material. For sterile packing of sterile goods in containers made of. such materialsit is necessary to sterilize .at least the surface of the-material prior to formation of the containers which surface will. be on the. inside of the containers after they are formed As a-rule only heat treatment assures a complete germicidal effect. The necessary sterilization temperature is. at least 200 C. The packing materials which are at least in part made ofv organic substances. usually are sensitive to heat. In materials which consist either entirely or partly ,of synthetic substances these substances soften at temperaturebelow the required sterilization temperature. Certain papers begin .to carbcnize already at temperatures above 200 C and become brittle or discolored at still lower temperatures. The surface of papers which is covered with synthetic. material and heated must not makecontaet ,with guiding or transport devices so that a complicated guiding and transport system mustbe provided. A temperature must be maintained which is just sufficient to effect sterilization and as low as'possible to avoid undesirable change of the packing material; This requires alongeri period of heating so that whenlheating the material while it travels towardthe container forming mechanism, a relatively long piece of material must beheated.
It is an object of the presentinvention to provide a method and means for'sterilizing striplike. material sub-. sequently used for producing sterile containers whereby the aforedescri-bed disadvantages anddifiiculties are suh-. stantially avoided. According to the invention the surface of the sheet-likematerial whichlforms the,inside of theccntainer subsequently produced from the, material '20 been endeavored to fill milk understerile conditions into conventional bottles and to apply suitable closures is heated prior to formation of the container to sterilizing temperature while, simultaneously, the opposite surface of the material which forms the outside. of thesubsequent- 1y formed container is cooled ,by contact-with aheat removingagent. This agent acts on-the.materialinthea samezone which is heated The aforedescribed method affords, prior to making the;
container,- heating of the; surface of the materialiwhich forms the inside of the susequently formedcontainer to considerably higher temperatures, considerablyireduning the required heating time without:damaging.; or pro-.
ducing undesired; changes inthe treated material. It has been found that it is sufiicient for obtaining isterile containers to heat to sterilization: temperaturetonly the, surface .of;the material Whichwill-be onthe inside ofthe subsequently formed containers, while simultaneouslyv cooling-the surface of the material =WhlQl15-f011113 r-theyoutside of thesubsequently formed containers. In this way P tmi ifi bthe heat can, be 'distributedthrough thethicknessof, the
material in such a manner that=the majorxpart ofrthe section of the material has atemperature which islconsiderahly below the; sterilization temperature which: is
produced on the heatedsurface .of the materials Inzs papersronevside of which is covered by alayer ofasyne thetic material this layer-maybeheatedto,250 C. Withe.
out, doing any damage to the paper on which the. layer :is
mounted. Thesurface of materialsawhich areentirely made of synthetic material which surface is on the inside of the subsequently produced container may be heatedto a temperature of- 250 C. or higher temperature :whilst the, opposite surfaceeofythe materialwhichuis on. the.
outside of the. subsequently produced container. lSl:SI1fl'l.-. ciently cooled to prevent softeni'ngof the synthetic material; the cooled surface can be guided on stationary guide:
surfaces without any danger of sticking of the'material on the guide surface due to the heating operation.
Thesur-faceof the material to be sterilized is preferably;
heated by heat radiation/or by means of a gaseous. or vaporous heat carrier. The opposite surface of the material is cooled-preferablyby blowing a gaseous or rvaporous coolant or by spraying alcoolant onto the surface. When movingmaterial of. relatively small breadth towards ,the
mechanism which forms containers rfrornthe material the surface to, be cooled mayrun over a cooledsurfacewith which the material is in contact; 7
It is also anobj'ect- .of the present invention tosprovide a device for carrying :out the aforesaid method This'device includes means for transportingfthe materialtowards'- a machine whlchforms containerstfrorn the:material and heatingmeans for-,heating the surfaceof the materialwhich forms: thelinside of the subsequently .forme'd containers while the materialist moved towards the container" forming machine,- cooling means being. provided which' simultaneously cool the side of the material which is opposite to .theheated. side of the material.
Electric radiators are. preferably used as heating means orrmeans may be; provided for-blowing'a gaseous or-va'-- porous heating medium onto, the surface of the material."
mended. that the surface of the'materiahwhich m'ust be i cooled rests on a cooled; preferably metallic, guide-surface which extends over the whole breadth -of-the mate;
rial. The guide surface may be stationaryor formed by I? the surfaceof a rotatable drumthroughlwhi hc la is conducted, theldrum beingarotated' by the moving metterial. Alternative'ly,- the material may move over' a cooledguidesurface which-is curvedabout an axis which is parallel to thedirection of movement of the material whereby, a convexomaterial surface isformed which is'.
heated and a concave materialsurface is -formedwh-ich is ,cooled'.
The novel features r whichtare considered characteristicof.the,;.invention areset forthwith particularity inthe ap-" pended 'claims. The invention itselffhoweven and additional objects '-.and,advantages.thereofrwill best be-under--- stoofihfrom thesfollowingpdescription of" embodiments l5 thereof when read in connection with the accompanying drawing in which:
FIG. 1 is a perspective diagrammatic illustration of a heating and cooling arrangement according to the invention.
FIG. 2 is a side View of a modified heating and cooling arrangement.
FIG. 3 is a sectional view taken along line III-III of the arrangement shown in FIG. 2.
FIG. 4 is a sectional view of a further modification of a heating and cooling device according to the invention.
FIG. 5 is a part sectional view of the device shown in FIG. 4, the view being taken at a right angle to the view of FIG. 4.
Referring more particularly to FIG. 1 of the drawing, numeral 1 designates a curved metallic guide surface 1 for guiding a strip of material 2 which is indicated by dashdot lines. The material consists, for example, of paper having a layer of synthetic material on one side. The material 2 rests with the paper surface on the guide surface 1 which is slightly broader than the breadth of the material. Before the material 2 reaches the guide surface 1 it passes underneath a roller 3. The guide surface 1 is the upper surface of a continuous strip of sheet metal 4 which surrounds a space 5 whose lateral sides are closed by plates 6 and 7.
At the end of the surface 1 from which the material 2 runs off a plurality of coolant distributing pipes terminate in the space 5. The pipes 8 are connected by means of a header with a pipe 9 which is connected to a source, not shown, of coolant, for example, water. At the end of surface 1 where the material 2 runs on, a plurality of pipes 10 are connected with the space 5 which pipes are connected by means of a header with a pipe 11 through which the coolant is continuously withdrawn after it has passed through the space 5.
Spaced from the surface 1 are a plurality of blow pipes 12 which are connected by means of a header with a pipe 13 through which a gaseous or vaporous heat carrier, for example, steam is supplied. The pipes 12 are provided with bores 14 through which the heat carrier is directed onto the top side of the material 2 which is covered by a layer of synthetic material.
The aforedescribed device operates as follows:
A coolant is passed through the chamber 5 which intensively cools the surface 1. T hereupon the material 2 is moved over the guide surface 1 by transport means, not shown, in the direction of the arrow 14. The heat carrier is now admitted through pipe 13 into the pipe 12 and blown onto the top surface of the material 2. The temperature of the heat carrier may be, for example, 400 C. The temperature of the coolant is approximately room temperature. The heat carrier heats the surface of the material 2 which will subsequently form the inside of the containers which are produced from the material 2, to approximately the temperature of the heat carrier whereas the surface of the material 2 which will form the outside of the containers is cooled to a temperature of less than 80 C. by contact with the cooled surface 1. In this manner any undesired change of the material 2 is avoided. Care must be taken that the material running off the device shown in FIG. 1 is not contacted by an atmosphere which contains germs. This can be done, for example, by conducting the material through a channel which is filled with pressurized sterile air.
In the embodiment of the invention shown in FIGS. 2 and 3 the material runs on the surface of a rotatable cylindrical body or drum 21. The latter consists of two halves 22 and 23 which are interconnected by means of bolts 24. The drum is supported by a shaft 25 which rests in ball bearings 26 and 27. The shaft 25 is provided with two axial bores 28 and 29 which extend almost to the center of the drum. Radial bores 30 and 31 connect the axial bores 29 and 28, respectively, with annular chambers 32 and 33, respectively, which are separated by means of an annular member 34 closely surrounding the center of the shaft 25. The annular chamber 32 is connected by means of radial bores 35, 36, 37 and 38 with an annular cavity 39 provided adjacent to the cylindrical surface of the drum. The channels 35 to 38 are individually located within ribs 40 of the drum half 23. Ribs 40a of the drum half 22 contain bores 42, 43, 44 and 45 which connect the annular cavity 39 with the annular chamber 33. The ribs 40 of the drum half 23 are offset 45 of the ribs 40a of the drum half 22. The bearings 26 and 27 are separated from the anular chambers 32 and 33, respectively, by packings 46. The annular cavity 39 is sealed from the outside by means of a packing 47.
A hollow radiator body 48 extends oppositely to a portion of the cylindrical surface of the drum 21, electric heating coils 48a being arranged inside the body 48. A coolant, for example, water is supplied through the axial bore 29 in the shaft 25 and flows through the channels or bores 35 to 38 into the cavity 39 and therefrom through channels or bores 43 to 45 into the bore 28 of the shaft 25. In this way the portion of the drum 21 which forms the guide surface for the material 20, and the material which is almost as wide as the drum is long, are intensively cooled. This arrangement prevents an undesirable change of the material 20 by the effect of the heat applied to the outside of the material from the radiator 48. The material 20 is moved by means, not shown, in the direction of the arrow 41 towards the machinery which forms containers from the material. The drum 21 is rotated by the moving material.
In the embodiment illustrated in FIGS. 4 and 5 a length of material 50 is conducted over the semicircular surface of two elements 51 and 52 so that the surface of the material 50 which subsequently forms the inside of the containers is convex and the surface which subsequently forms the outside of the containers is concave. The material 50 is moved by means, now shown, in the direction of the arrow 53. A semicircular electrically heated radiator 54 is placed opposite the material 50 between the elements 51 and 52 for heating the convex surface of the material to sterilization temperature. A hollow body 55 of semicircular cross sectional configuration is placed between the elements 51 and 52. The axis of the curvature of the curved surface of the body 55 is parallel to or coincides with the axis of the semicircular surfaces of the elements 51 and 52. A coolant, for example, Water or air is supplied through a pipe 56 to the inside of the hollow body 55. The curved Wall of the body 55 is provided with bores 57 through which the coolant is directed onto the concave surface of the material 50. The coolant is diverted downwards by the material so that it cannot come in contact with the convex side of the material which must be sterilized.
In many cases it is desired that also the cooled surface of the material is temporarily sterilized until the container made from the material is filled and hermetically sealed. This can be effected by admixing a sterilizing agent, for example, permanganate or ozone to the coolant, or by bringing such a sterilizing agent in contact with the surface of the material which will form the outside of the subsequently produced containers during or after heating of the material.
The invention is not limited to the described examples. It is also suitable for treating material which consists only partly of organic substances, for example, a flexible strip of paper to which a layer of synthetic material is applied and which has an inlay in the form of an aluminum foil. Instead of electrically heating the radiator this may be done by means of a gaseous or vaporous heat carrier.
1. In a system for producing sterile containers from continuous striplike material consisting at least in part of organic substances, transport means for conveying the material towards container forming means, said transport means including sterilizing means, the latter including cooling means placed on the side of the material which side is on the outside of the subsequently formed containers, and heating means placed opposite said cooling means on the side of the material which side is on the inside of the subsequently formed containers, for heating the surface of the material which surface is on the inside of the subsequently formed containers to a temperature of at least 200 C. while the other side of the material and thereby the body of the material is cooled.
2. In a system as defined in claim 1 and wherein said cooling means includes an element having a stationary convexly curved cooled surface slidably supporting and being in contact with the striplike material throughout the entire width of the material.
3. In a system as defined in claim 1, guide means for bending the striplike material around an axis parallel to the longitudinal axis of the material, said cooling means being placed on the concave side of the bent striplike material.
4. The improvement in the art of producing sterile containers from continuous striplike material, which comprises continuously moving the material towards container forming means, sterilizing by heating to at least 200 C. the surface on the side of the material, which forms the inside of the subsequently formed container, while the material moves towards the container forming means, and simultaneously cooling the opposite surface of the material which surface is at the outside of the subsequently formed containers.
References Cited in the file of this patent UNITED STATES PATENTS 1,867,256 Egli July 12, 1932 2,297,314 Otfen Sept. 24, 1942 2,497,212 Donofrio Feb. '14, 1950 2,816,837 Holsman Dec. 17, 1957 2,928,219 Gubler Mar. 15, 1960