Page 1
`
`GEA Process Engineering, Inc. Exhibit 1062
`GEA Process Engineering, Inc. v. Steuben Foods, Inc.
` IPR2014-00041, -43, -51, -54, -55
`
`

`

`United States Patent
`m] Patent Number:
`4,631,173
`Miiller et a1.
`{45] Date of Patent:
`Dec. 23, 1986
`
`
`{19;
`
`[76]
`
`[54} METHOE} 0F STERILEZING FACKAGING
`MATERIAL, ESPECIALLY
`CONTAINER-TYPE PACKAGES
`..
`Inventom Horst Muller, Westerwaldweg 12.
`4020 Mettmann; Gerhard Deimel,
`Kelberger Str. 83, 5090 Leverkusen
`3, both of Fed. Rep. of Germany
`[21] Appl. No.: 775,103 '
`.
`,
`[22] Filed:
`5:29.11, 1935
`
`U
`
`[5%
`
`References Cited
`0C
`.S. PA'I‘ENT D
`UMEN’I‘S
`
`1/1976 Eggcr .................................... 422/28
`3,933,428
`
`1/1978 Gustafsscn et ai.
`412/28
`4,099,914
`......
`9/1979 Moore er. al.
`422/29
`4,[69,123
`
`9/1980 Lothman et a].
`422/28
`4,225,556
`4,296,668 10/1981 Hashim .............................. 422/30;
`Primary Examinermlvars Cintins
`Attorney, A em, or Firm—S run Horn Kramer &
`Woods
`3
`P
`3
`
`[63}
`
`Related us. Appiicatim. Data
`Continuation of Se:. No. 441,143, Nov. 12, £932, aban-
`doned.
`.
`.
`.
`.
`.
`P
`A 1
`h
`F
`0
`pp we on minty
`oreign
`[3 I
`Fed. Rep. of Germany ....... 3145274
`Nov. 14, 1931 [DE]
`Fad' Rep. of Sammy """" 3235476
`SCP' 24’ 1982 [DE]
`
`{51]
`Int. (21.4 ................................................ AGIL 2/20
`
`{52} U.S. Ci.
`............... 422/28
`{53] Field of Search .......................... .. 422/28, 29, 302
`
`Data
`
`Answer
`[57]
`A method of stediizing containers with hydrogen per-
`oxide which comprises combining a liquid containing
`the peroxide with compressed air and atomizing the
`.
`.
`.
`combination onto a heated surface to effect vaporiza-
`tion Of the liquid, and immediately blowing thfl mixture
`of vapor and air over the area to be sterilized. A suitable
`apparatus is shown»
`
`6 Claims, 5 Drawing Figures
`
`15
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`
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`
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`Page 2
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`STEUBEN054121
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`US. Patent Dec=.23,1986
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`sagetlofs
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`4,631,173
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`A:5
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`H FIG1
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`US. Patent Dec. 23, 1986
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`Sheet 2 of S
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`US. Patent Eta-23,1986
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`SheetSofS
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`4,631,173 -
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`US. Patent Dec.23,1986
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`Sheet4of5
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`.U.S.Patexit Dec.23,1986
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`.Sheetfiofs
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`4,631,173
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`STEUBEN054126
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`METHOD OF STERILIZING PACKAGING
`MATERIAL, ESPECLALLY CONTAINER-TYPE
`PACKAGES
`
`5
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`i0
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`[5
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`20
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`25
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`30
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`35
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`4D
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`45
`
`This application is a continuation of application Ser.
`No. 441,l43, filed Nov. 12, 1982, now abandoned.
`The invention concerns a method of sterilizing pack-
`aging material, especially centainer-type packages, with
`a liquid disinfectant containing hydrogen peroxide, a
`method in which the disinfectant is atomized and com-
`bined with compressed air and the combination evapo-
`rated and blown in the form of a mixture of vapor and
`air over the area of packaging material to be sterilized,
`where the vapor is condensed. The invention also con-
`cerns apparatus for carrying out this method
`The germicidal action of hydrogen peroxide has long
`been exploited in packaging technology. Various meth-
`ods of applying more or less concentrated hydrogen
`peroxide to the packaging-material surface to be steril-
`ized are known. In one known method (German AS
`No. l 815 538) a liquid disinfectant that contains hydro-
`gen peroxide is sprayed through an atomizer nozzle
`directly into container‘type packages before they are
`filled with a product, and the resulting mist precipitates
`as fine droplets of water on their walls. Hot air is then
`introduced into the packages to evaporate the hydro-
`genuperoxide mist and decompose the hydrogen perox~
`ide into the active state, in which it is finally expelled
`from the package.
`In another and similar known method (German AS
`No. 2 744 637 and 08 No. 2 310 661), to which the
`present invention is applicable, a liquid disinfectant that
`contains hydrogen peroxide is atomized and then evap-
`orated with hot air, after which the mixture of vapor
`and air is blown over the area to be disinfected. Since
`the temperature of the area to be disinfected is kept
`lower than the dew point of the mixture of vapor and
`air, a condensate will form on it. In this method the
`disinfectant
`is atomized with an ultrasound nozzle,
`through which the disinfectant is blown in the form of
`a fine mist into a mixing chamber subjected to hot air.
`The disinfectant mist will, because of the fineness of its
`droplets, continuously evaporate inside the mixing
`chamber, and the resulting mixture of vapor and air is
`continuously blown through a tube that communicates
`with the mixing chamber into a chamber that the paclo
`aging material continuously travels through in the form
`of a web.
`This known method is practical for sterilization pro- 50
`ceases in which the disinfectant is applied to the packag-
`ing material in cycles, as in the known method (AS No.
`1 tits 538) mentioned in the foregoing, only when cer-
`tain disadvantages that can itapair its effectiveness are
`taken into account. To ensure that a complete dose of
`the mixture of vapor and air formed out of the disinfec-
`tant can be obtained during the brief interval during
`which the work unit is performed, to completely exploit
`the germicidal action, that is, it must be profisionally
`stored in a butler reservoir, which it is extracted from at
`controlled intervals and blown over the packaging ma
`terial. This is because ultrasound atomizing, which is
`necessary to obtain droplets of the desired fineness, can
`not be initiated rapidly enough for the mist to be avail-
`able precisely at the commencement of a work unit.
`Still, it is undesirable to store the mixture of vapor and
`air because the hydrogen peroxide, brought to a high
`temperature by the hot air, tends to decompose prema-
`
`55
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`4,631,173
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`turely and the germicidal action of the mixture that is
`ultimately blown over the packaging material deterio-
`rates.
`
`The present invention is intended as a method of the
`type described in the Foregoing and as apparatus for
`carrying out the method that can be employed for the
`cyclic sterilization of packaging material without detri-
`ment to its germicidal action.
`This objective is attained in accordance with the
`invention in that the disinfectant is atomized with com—
`pressed air onto a heated surface and hence evaporated
`and in that the mixture of vaporand air is immediately
`blown over the area to be sterilized.
`In the method in accordance with the invention. the
`liquid disinfectant
`is atomized directly by the com-
`pressed air, which then becomes a carrier for the disin-
`fectant as the process continues, itself. The dismfectant
`can for example be vaporized with a binary nozzle, so
`that it can also be mixed as required with the com-
`pressed air at the same time that it is being finely divided
`into droplets. Atomizing the disinfectant onto a heated
`surface that has a temperature cousiderably higher than
`the evaporating point of the disinfectant evaporates the
`droplets extraordinarily rapidly as they strike the sur-
`face. The resulting vapor is immediately entrained by
`the current of compressed air generated during atomizaw
`tion and arrives immediately, within fractions of a sec-
`ond, that is, at the cooler packaging~material area that is
`to be sterilized, where it condenses as a fine film or in
`finely divided droplets. The amount of condensate can
`be controlled with extreme precision by varying the
`amount of disinfectant that is atomized.
`One embodiment of the invention considerably pro-
`motes the distribution of vapor within the current of air
`that derives from atomization by generating powerful
`turbulence in the current of air or of vapor and air. This
`turbulence can be generated by directing the jet of
`compressed air that atomizes the disinfectant obliquely
`against the heated surface, which has projections or
`irregularities that produce the turbulence.
`As mentioned in the foregoing, the acme] sterilization
`is the result of the condensation of the mixture of vapor
`and air on the packaging-material surface, which is kept
`cool for this purpose, the temperature of the material
`being definitely below the dew point of the mixture.
`The condensate is subsequently dried in a known man—
`ner by blowing hot air over it.
`_
`In one somewhat diii'erent embodiment of the inven—
`tion, however, the area to be sterilized is heated before
`the mixture ofvapor and air is blown onto to it to a
`temperature equal to or only slightly below the dew
`point of the mixture. This also produces, although only
`very briefly, at condensate on the surface being treated.
`This condensate evaporates by itself because of the
`higher temperature of the mixture and the resulting
`local temperature elevation. When the hydrogen-perox-
`ide concentration is high enough (35% for instance), the
`condensate will remain on the surface long enough to
`sterilize it. Subsequent drying with hot air is not neces-
`sary and heat-sensitive packaging materials can be dried
`with relatively cooler air.
`,In another embodiment of the method, the wall sur-
`faces of container-type packages that are to be sterilized
`and that have well surfaces of different temperature are
`variably cooled or heated to equalize the temperatures
`in the areas to be sterilized. The temperatures may be
`non-uniformly distributed for instance when packages
`are washed with hot water or a similar material hamedi-a
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`4,631,173
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`3
`ateiy before being filled with a product and the varying
`wall thickness will result in irregular cooling as they
`reach the sterilization station. Packages made of card-
`board blanks and with heat~sealed floors will also con-
`tinue to exhibit a higher temperature at the floor, which
`is folded into several layers and retains heat from the
`sealing process, than at the walls, which are not sub-
`jected to scaling, during sterilization. The controlled
`cooling of such heated areas will balance the tempera—
`ture and promote uniform condensation over all the
`areas to be sterilized.
`The apparatus for carrying out the method in accor-
`dance with the invention has a conveyor for transport-
`ing the packaging material, especially container-type
`packages, a reservoir holding a liquid disinfectant that
`contains hydrogen peroxide and communicating with a
`device that atomizcs the disinfectant, an evaporator
`downstream of the atomizing device, and a tube
`charged with compressed air, communicating with the
`evaporator, and opening above the packaging material
`in the vicinity of the conveyor.
`The problems discussed in the foregoing are solved in
`accordance with the invention in that the device that
`atomizes the disinfectant is an atomizer nozzle charged
`with compressed air and positioned immediately in
`front of the entrance to the tube with the axis of its jet
`at least approximately parallel to the axis of the tube in
`the vicinity of the entrance and in that the inside surface
`of the tube can be heated by a heating device to a tem-
`perature that is definitely higher than the evaporation
`temperature of the disinfectant.
`The inside surface of the tube is the heated surface
`that the mixture of finely atomized disinfectant and
`compressed air produced by the atomizer nozzle arrives
`at. The thrust of compressed air produced by the atom-
`izer nozzle and the rapid evaporation of the droplets
`arriving at the inside surface of the tube blows a jet that
`consists of a mixture of vapor and air out of the tube
`exit, which is positioned immediately above the packag-
`ing material, above the open top of a package for in~
`stance.
`It is practical for the atomizer nozzle to be immedi—
`ately in front of the tube entrance, to which it may even‘
`be rigidlyattached. The tube is enclosed over most of
`its length in a preferably electric heating jacket that
`supplies enough heat to keep the temperature of the
`inside surface of the tube high enough in spite of the
`amount of heat removed during every evaporation pro-
`cars.
`
`In one practical embodiment of the invention the
`inside surface of the tube has projections to itmrease the
`heat-emission surface and also-produce turbulence. In
`one ingenious solution these protections can be formed
`by a helical metal spring that fits deep into the tube. Its
`outer surface can be ground cylindrical if need be to
`increase the contact surface with the inside surface of
`the tube. It is also practical for at least one deflecting
`body to be inserted in the tube, extending from the
`inside surface to beyond the middle of the free tube
`cross-section, to prevent droplets ejected from the at=
`ornizer nozzle from traveling directly along the
`{straight} axis of the tube to its exit, so that they do not
`get evaporated.
`Other advantages and characteristics of the present
`invention will be evident from the following specifica-
`tion of examples of embodiments with reference to the
`accompanying drawings and from the subsidiary claims.
`In the drawings,
`
`Page 9
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`4
`FIG. 1 is a schematic representation of apparatus in
`accordance with the invention,
`FIG. 2 a larger-scale schematic representation of the
`combination atomizer, evaporator, and blower device
`employed in the apparatus illustrated in FIG. 1,
`FIG. 3 illustrates one practical embodiment of the
`combination device illustrated in FIG. 2,
`FIG. 4 is a diagram illustrating a method of operation
`that differs slightly from that illustrated in FIG. 1, and
`FIG. 5 illustrates another embodiment that differs
`slightly form that illustrated in FIG. 1.
`FICm 1 is a schematic representation of apparatus for
`sterilizing container-type packages 1. This apparatus is
`part of a packaging plant, the other parts of which are
`not illustrated and in which the packages, manufactured
`from thermoplastic-coated cardboard blanks, are steril»
`iced, filled with a product, milk for example, and finally
`sealed. Plants of this type are known and need not be
`specified herein.
`Packages 1 are transported in a schematically illus-
`trated conveyor 2, which may be a cell chain or similar
`mechanism, in which they are held positively and up-
`right. The conveyor advances packages 1 at regular
`intervals of l.2 seconds for example in the direction
`indicated by the arrow. At the conveyor entrance pack—
`ages 1 pass through a sterilization station 3 and then
`through a drier station 4 that consists of seven individ»
`ual positions, each with its own work interval.
`.
`A combination atomizer, evaporator, and blower
`device 5, which will be separately specified subse-
`quently, is mounted above the path of packages 1 in the
`sterilization station, which is labeled on the whole with
`reference number 3. Device 5 communicates through a
`line 6 with a reservoir 7 of liquid disinfectant, which
`may for example be a 35% aqueous solution of hydro-
`gen peroxide. Line 6 contains a metering device 8, in
`itself known, through which precisely measured por-
`tions of disinfectant are supplied to device 5. Device 5
`also communicates through a line 19 with a source 11 of
`compressed air, a compressor for example, which is
`illustrated completely schematically. The supply of
`compressed air is monitored and controlled by controls
`12, which are also illustrated only schematically.
`Heated sterile air is supplied through a line 13 to a
`hot—air distributor 14 in drier station 4. Blower nozzles
`15 are positioned extending down from hotnair distribu-
`tor 14 in such a way that they can blow a specific
`amount of sterile-hot air at a specific temperature (80“
`C. for example) into packages 1 in- each of the seven
`individual positions in drier station 4. This air is ob-
`tained from an air reservoir 17 and heated in a heater 16.
`FEEL-2 illustrates combination atomizer, evaporator,
`and blower device 5 in greater detail. This figure also
`illustrates a cell chain 2 that is somewhat different from
`that illustrated in FIG. 1. Device 5 is essentially a com-
`mercially available binary atomizer nozzle 51 that corn-
`municates through line 6 with disinfectant reservoir 7
`and is charged through line 10 with compressed air. An
`upright tube 52, made out of a material like metal that
`conducts heat well, is positioned coaxial with the axis of
`the jet from atomizer nozzle 51 and enclosed in an clec~
`trio heating jacket 5:}. Tube 52 opens-unmediatcly above
`the open top of a container-type package 1. A slightly '
`peaked handle 54 is mounted at the exit of tube 52 and
`extends somewhat beyond'the cross—section of package
`1. A helical spring 55, preferably made out of chrome-
`nickcl steel, fits into tube 52 in such a way that its coils
`are in heat-conducting contact with the inside surface of
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`5
`the tube. Three deflection plates 56 are attached to
`spring 55 at approximately equal intervals along the axis
`of the tube. Deflection plates 56 in the form of a circle
`with a segment cut out and slant from the inside surface
`of tube 52 across its cross—section to beyond its longitu—
`dinal axis, so that only part of the open cross section of
`the tube is available for flowthrough. Deflection plates
`56 are locally welded or soldered to spring 55. In the
`embodiment illustrated by way of example in FIG. 2,
`spring 55 extends along almost the total length of tube
`52.
`Although the cell 21 of cell conveyor 2 illustrated in
`FIG. 2 is manufactured in a known way out of metal, it
`has, in accordance with the invention, beads 22 and 23
`on to bottom and sides respectively that extend inward
`so that the package 1 in cell 21 comes into contact only
`with their relatively narrow edges. The lines at which
`beads 22 and 23 contact package 1 can also be coated
`Mth a heat-insulating material to prevent heat from
`flowing from cell 21 into the walls of package 1 or vice
`versa,
`leading to uncontrollable and undesirable
`changes in the temperature of the package wall.
`In the practical embodiment of combination atom-
`izer, evaporator, and blower device 5 illustrated in FIG.
`3, atomizer nozzle 5}, which is of a commercially avail»
`able type, is attached, screwed for example, directly to
`the top 57 of tube 52. The top 57 of the tube accordingly
`expands like a funnel, forming a connector 58 that corn-
`pletely surrounds atomizer nozzle 51. The body, not
`illustrated in FIG. 3, of atomizer nozzle and its associ-
`ated connections are outside connector 58. The tube 52
`illustrated in FIG. 3 is for example 28 cm long and its
`well is 5 mm thick. This is to ensure that the wall of tube
`52, which is electrically heated externally by heating
`jacket 53, will have enough thermal capacity that no, or
`only insignificant, temperature fluctuations will occur
`in it during operation. Tube 52 and heating jacket 53 are
`mounted in a housing 59 that has a junction box 60 for
`the electricity for jacket 53 mounted on it. The electri-
`cal connections 61 for jacket 53 are not completely
`illustrated. Tube 52 extends through the floor 62 oftube
`52. The underside of floor 62 is protected with heat
`insulation 63. A thermostat 65 is positioned below heat
`insulation 63 in a mount 64. Thermostat 65 extends
`through a hole 66 bored in tube 52 and controls the
`supply of heat to heating jacket 53 and hence the tem-
`perature of the inside surface of tube 52 in accordance
`with the temperature of the mixture of vapor and air
`flowing through the tube. Baffle 54 is attached to the
`underside of a plate 67 on which housing 59 is mounted.
`Package 1 is represented by a clot-dash line to illustrate
`its distance from the exit of tube 52 and from baffle 54.
`In the embodiment illustrated in FIG. 3, the helical
`spring 55 inside tube 52 does not extend along the whole
`length of the tube, but only from its exit to about i of its
`length. Several deflection plates 56 shaped as described
`with reference to FIG. 2 are distributed at irregular.
`intervals along the inside of tube 52. To prevent it from
`being displaced by the water hammer of atomizer nor.
`ale 51, spring 56 rests on a shoulder 68 in tube 52.
`How the method in accordance with the invention is
`carried out in conjunction with the apparatus specified
`with reference to FIGS. 1 through 3 will now be speci-'
`fied.
`Programmed by the controls, not illustrated, for the
`overall packaging plant, cell chain 2 advances one stop
`until a package 1 arrives at sterilization station 3 (FIG.
`1). Atomizer nozzle 51 will subsequently be controlled
`
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`6
`by the programming and by controls 12 in such a way
`that compressed air will be supplied to it through line 10
`and an amount of disinfectant that has been precisely
`portioned out by metering device 8 will be supplied to
`it through line 6. Atomizer 51 will also be operated at
`previously selected intervals of time. It employs the
`compressed air supplied to it to atomizc the disinfectant
`in a known manner to a mist with a mean droplet size of
`approximately 20—50,». The water hammer that occurs
`as the result of the position of atomizer nozzle 51 di»
`rectly in front of the entrance to tube 52 (FIG. 2) or in
`connector 58 (FIG. 3) flings the droplets of the mixture
`of air and disinfectant against the inside surface of the
`tube, where they evaporate very rapidly because of the
`temperature prevailing there. Although a film of liquid
`disinfectant may tend to collect at the entrance to tube
`52 during atornization, the powerful current will entrain
`it to the vicinity of helical spring 55, where turbulence
`will seize it and it will rapidly evaporate upon contact
`with the heated surface. Spring 55 will in any case pre-
`vent liquid disinfectant from leaving tube 52. Deflection
`plates 56, which partly block the inside cross-section of
`tube 52, will prevent droplets expelled parallel to the
`axis of the tube from precipitating unevaporated out of
`it and getting into package 1. A directed jet of a mixture
`of vapor and air leaves the exit of tube 52 and enters
`package 1, where it strikes against the walls and floor.
`Since the walls and the floor of package 1 are at a tem—
`perature below (20‘ C. below, for example) the dew
`point of the mixture of vapor and air, the moisture in the
`mixture will condense on the inside surface of package
`1, forming a thin and uniform film or finely divided
`droplets of disinfectant. Since the packages 1 in the
`embodiment illustrated in FIG. 2 are held in cell 21 in
`such a way that they contact the cell only at the edges
`of beads 22 and 23, there will be no preferred—condensa-
`tion areas in which larger amounts of droplets can form
`and that would be difficult to dry during the subsequent
`drying process.
`Since the mixture of vapor and air is supplied in en
`cess to package 1, some of it will exit at the top, where,
`however, it will be diverted by baffle 54 to and will
`sterilize the cut edges and the inside and outside borders
`of package 1.
`After one work interval, conveyor 2 will travel on
`and package I will arrive with the condensate on its
`walls at the first position of drier station 4. The conden-
`sate is completely eliminated as the package travels at
`regular intervals through the seven positions of drier
`station 4, in which hot air is blown from hot-air distribu—
`tor 14 into package 1. Since the hot air has a tempera
`ture of only 80“ C. for ample, no excess heat is sup-
`plied to the walls of the package, which is a special
`advantage with regard to thermoplastic-coated pack-
`ages, especially at the scoring. This prevents damage to
`the thermoplastic coating.
`The apparatus illustrated in FIG. It differs from that
`in FIG. 3 in that the hotvair distributor 14 in drier sta-
`tion 4 extends over only five positions and in that there
`is a reaction station 9 that the package travels through
`in two work intervals upstream of drier station 4. The
`condensate is allowed to remain on the inside surface of
`the package as it travels through reaction station 9 so
`that the disinfectant will have enough time to com-
`pletely Bill of? even especially resistant germs.
`In the apparatus illustrated in FIG. 5, the process of
`atomization, evaporation, and blowing occurs as speci-
`fied in the foregoing. This embodiment differs. how-
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`4,631,173
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`7
`ever, in that the inside surfaces of packages 1 are pro-
`heated in a preheating station 16 that is upstream of
`sterilization station 3 and that it takes two work inter—
`vals for them to travel through to a temperature equal
`to or slightly below the dew point of the mixture of S
`vapor and air produced in apparatus 5. A hot—air distrib~
`utor 14 is mounted above the path of packages 1
`through preheating station 16 to preheat them with hot
`air blown through their nozzles 15. The disinfectant in
`the mixture of vapor and air that is blown into packages 19
`1 in sterilization station 3 also condenses in this embodi—
`ment on the inside surface of the packages, butcnly
`briefly because the temperature of the mixture heats the
`surface to slightly above the dew point, so that the
`surface itself can evaporate the recently formed con— 15
`densate. Since the condensate remains on the surface
`only briefly, the air that is supplied over a drying-air
`distributor 143 in order to dry packages 1 in the drier
`station 4 downstreamiof sterilization station 3 can be
`relatively cool.
`If the walls or floor of packages 1 exhibit a non-
`uniform temperature distribution as the remit of previ~
`ous heat treatment, as will be the case when. the floor
`has recently been.heat~sealed, it may be necessary to
`cool them localiy to allow or to prevent condensation. 25
`In this case it will be practical, instead of supporting the
`packages 1 with the beads 22 as illustrated in FIG. 2, to
`provide the cells with a floor on which the package will
`. stand flat. The floor of the cell will remove heat locally
`from the floor of the package as it travels to the steril— 30
`izatibn station and assimilate its temperature to that of
`the walls. if this heat removal is not adequate, the floor
`of the package can be locally cooled further by cold-air
`nozzles. not illustrated, positioned below conveyor 2.
`The amount of disinfectant in the mixture of vapor 35
`and air, the temperature of the mixture, and the temper-
`ature of the walls of the packages are all adjusted to
`control the extent to which the disinfectant condenses
`on the walls.
`The temperature of the inside surface of tube 52 40
`ranges from 150' to 250° C.
`'
`'
`'
`We claim:
`1. A method of sterilizing containers being conveyed
`along a path and stopped intermittently in a sterilizing
`station, comprising the following steps:
`
`-
`
`.
`.,
`8
`intermittently injecting a liqttid disinfectant contain— .
`ing hydrogen peroxide from a nozzle when the
`containers stop and atomizing the disinfectant into
`fine droplets when the containers stop by means of
`an intermittent stream of comprwsed air to thor-
`oughly mix the atomized sterilizing agent and the
`stream of compressed air,
`directing the resulting combined stream onto a heated
`surface that has a temperature sufficient to rapidly
`evaporate the disinfectant in the mixed stream,
`_ generating turbulence in the mixed stream to acceler-
`ate the droplets of disinfectant against the heated
`- surface and to evaporate them there,
`orienting the heated surface so that the resulting
`' stream of compressed air and vapor is diverted by
`the heated surface directly onto the inside of the
`cuntainer,
`'
`.
`disposing the inner surface of the container at a tem-
`perature below the condensation point of the
`stream of'compressed air and vapor,
`condensing the disinfectant vapor onto the inner sur-
`face of the cuntaiuer, and
`blowing hot air into the container to dry its inner
`surface.
`'
`.
`2. The method as in claim 1, wherein the area to be
`sterilized is heated, before the mixture of vapor and air
`is blown over it, to a temperature that approximates the
`dew point of the mixture and wherein relatively cool
`gas is Blown over the area after a predetennined reac-
`tion time that is subsequent to the time at which the
`mixture of vapor and air is' blown over it.
`3. The method as in claim 1, wherein the areas to be
`sterilized are heated or cooled to attain a uniform tem-
`perature distribution before the mixture of vapor and air
`is blown over them.
`-
`4. The method as in claim 1, wherein the turbulence
`is generated by blowing the mixture of vapor and air
`obliquely over the heated surface.
`5. The method as in claim I, wherein the mixture of
`vapor and air is Mom with the compressed air used to
`sterilize the disinfectant.
`6. The method as in claim. 1, further compfising cool-
`ing the floor of the container before the nurture of
`vapor and air is blown into them.
`-
`*
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