Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B55/00—Preserving, protecting or purifying packages or package contents in association with packaging
  • B65B55/02—Sterilising, e.g. of complete packages
  • B65B55/04—Sterilising wrappers or receptacles prior to, or during, packaging

Definitions

• the present invention generally relates to the sterilization of containers. More particularly, the present invention concerns a method of sterilizing food packaging containers that are filled with food and sealed, and a sterilizing device for sterilizing such packaging containers.
• FIG. 2 shows a conventional food packaging system of the type generally described in Japanese Patent Laid-Open Publication No. 255128/1987.
• this packaging system 51 forms packaging containers 53 folded in a plate-like shape into bottomed containers having a bottom 53a. After the containers have been filled with liquid food, a seal is provided on the respective containers.
• the system includes a transfer conveyor that intermittently and continuously transfers the packaging containers 53 and a forming device 55 that forms folded packaging containers 53 into bottomed containers to feed them onto the transfer conveyor.
• a filling device 57 fills food product from above into the packaging containers 53 moving on the transfer conveyor, and a sealing device 59 seals the top of the packaging containers 53 filled with the food product.
• packaging containers 53 can be continuously filled with liquid food and packaged in the sealed state.
• the sterilizing agent can be hydrogen peroxide.
• the hydrogen peroxide is used only for sterilization.
• the hydrogen peroxide must be thoroughly removed before commencing the filling of the food product so that residual hydrogen peroxide in the container is kept below a specified value.
• the present invention provides a sterilizing method and device which makes it possible to thoroughly and reliably remove the hydrogen peroxide in a short period of time by using a simple approach and configuration.
• One aspect of the invention involves a method of sterilizing food packaging containers.
• the method includes depositing a hydrogen peroxide-containing solution having a concentration in the range of 0.05 - 0.20 wt. % into the interior of a packaging container before the container is filled with food product, irradiating the interior of the container with ultraviolet light after the hydrogen peroxide-containing solution is deposited in the interior of the container, and removing hydrogen peroxide from the interior of the container by blowing compressed hot air into the interior of the container.
• a sterilizing device for food packaging containers that includes a sterilizing agent depositing device for depositing a hydrogen peroxide-containing solution having a sterilizing affect into the interior of a packaging container before the interior of the container is filled with food product, an ultraviolet light irradiation device for irradiating the interior of the container with ultraviolet light after the hydrogen peroxide- containing solution has been deposited into the interior of the container, and a sterilizing agent removing device for removing hydrogen peroxide from the interior of the container by blowing compressed hot air into the interior of the container.
• a sterilizing agent depositing device for depositing a hydrogen peroxide-containing solution having a sterilizing affect into the interior of a packaging container before the interior of the container is filled with food product
• an ultraviolet light irradiation device for irradiating the interior of the container with ultraviolet light after the hydrogen peroxide- containing solution has been deposited into the interior of the container
• a sterilizing agent removing device for removing hydrogen peroxide from the interior of the container by blowing
• the compressed hot air is blown into the container interior to which a hydrogen peroxide-containing solution is deposited.
• the compressed hot air thermally decomposes the hydrogen peroxide to form water and oxygen, and rapidly vaporizes the water after decomposition.
• hydrogen peroxide can be thoroughly and reliably removed in a short time period through use of a simple method and construction.
• the present invention it is possible even in the context of a packaging system that continuously fills contents into packaging containers which are intermittently and continuously transferred by a transferring device to thoroughly remove hydrogen peroxide from the container interior in a short time period so that both the productivity and food quality holding affect can be improved.
• FIG. 1 is a perspective view of a packaging system using a sterilizing device in accordance with the present invention.
• Fig. 2 is a perspective view of a conventional food packaging system.
• the packaging system 1 of the present invention is designed to form a bottom 3a on a rectangular cylindrical food packaging container 3. After the container interior is sterilized, the system fills the bottomed container with contents such as a liquid food product (e.g., juice). The container is filled through the opening on the top side 3b of the container and the open top side of the container is then sealed.
• the system is equipped with a conveyor 5 that functions as a transferring device or means for intermittently and continuously carrying packaging containers 3.
• the driving member can be in the form of a chain or belt.
• a forming device 7 forms a bottom 3a for the rectangular cylindrical packaging container 3 and feeds the container onto the conveyor.
• a sterilizing device 9 sterilizes the inside of the packaging container 3 that is moving on the conveyor 5 and a filling device 11 fills the inside of the packaging container 3 on the conveyor 5 with food from above.
• a sealing device (not specifically shown in Fig. 1) then seals the top side 3b of the packaging container 3 that is filled with food.
• the packaging container is made of a flexible sheet formed into an approximately rectangular tube, the sheet being made of a paper material on both sides of which a resin material is laminated.
• the packaging container is folded flat and is stored with other flat folded containers in a magazine.
• the resin material in the opening areas on both the bottom side 3a and the top side 3b of the packaging container 3 constitutes a thermoplastic layer for bonding.
• the packaging container 3 is provided with a plurality of fold lines to partition it into the side wall panels, the bottom wall panels on the bottom side 3a, and the top wall panels on the top side 3b.
• the forming device 7 for forming the bottom of the container is provided with a mandrel wheel 13, a bottom heater (not shown), and a bottom pressing device (not shown).
• the mandrel wheel 13 includes a core 15 that is rotatably indexed, and mandrels 17 that are spaced around and extend radially outwardly from the core 15.
• a packaging container is brought up from the magazine in the form of a rectangular cylinder having an approximately square section and is fed to the mandrel wheel 13.
• the packaging container is fed in the longitudinal direction, along the direction of the container axis, during loading onto the mandrel 17.
• the mandrel wheel 13 is indexed by being turned one step, and another packaging container 3 is then loaded onto the next mandrel 17.
• the bottom wall panels on the bottom 3a side of the packaging container 3 that protrude from the end of the mandrel 17 are heated by hot air heated by the bottom heater. This results in the temperature of the thermoplastic layer being raised to a softening temperature suitable for effecting sealing. Then, when the mandrel wheel 13 is indexed from the first indexing position to the next indexing position, the heated bottom wall panels are folded inwardly in overlapping relation to one another so that an approximately flat bottom 3a is formed.
• the bottom 3a is pressed and cooled by the pressing device so that the bottom panels are firmly bonded in a water-tight manner to one another through the thermoplastic layer.
• the result is the formation of a bottom 3a that is water tight and hermetically sealed.
• the packaging container 3 When the mandrel wheel 13 is further rotatably indexed, and the packaging container 3 having the sealed bottom 3a and free from liquid leakage is brought above the conveyor 5, the packaging container 3 is pulled down in the vertical direction and placed on the conveyor 5.
• Located above the conveyor 5 are a top prefolder, a sterilizing device 9, a filling device 11 , and a sealing device (not specifically illustrated).
• the packaging containers 3 placed on the conveyor 5 from the mandrel wheel 13 are intermittently transferred in contiguous pairs, and first pass through the top prefolder (not specifically illustrated).
• the top prefolder By virtue of the operation of the top prefolder, the top wall panels on the container are slightly folded before being transferred to the sterilizing device which is positioned downstream.
• the sterilizing device 9 is provided with a sterilizing agent depositing device 19, an ultraviolet light irradiating device 21, and a sterilizing agent removing device 23 that are arranged upstream of the conveyor 5 for carrying out the sterilizing process.
• the sterilizing agent depositing device 19 includes sterilizing agent injection nozzles 25, each of which is located approximately above the center of the top opening in the pair of contiguous packaging containers 3 that are intermittently transferred and stopped on the conveyor 5.
• a sterilizing agent in the form of a hydrogen peroxide-containing solution is continuously injected into the container interior from the sterilizing agent injection nozzle 25.
• the ultraviolet light irradiating device 21 includes an ultraviolet light irradiating lamp that is located above the top opening in the pair of contiguous packaging containers 3 that are intermittently transferred from the sterilizing agent depositing device 1 and stopped.
• the interior of the container is irradiated with ultraviolet light from the ultraviolet light irradiating lamp, which ultraviolet light has a sterilizing affect.
• the sterilizing agent removing device 23 for effecting removal of sterilizing agent includes two hot air nozzles 27, 29, an air pipe 31, a heater 33, a dust removing filter 35, a flow-rate adjusting butterfly valve, and a compressor 37.
• the hot air nozzles 27, 29 are each located to be approximately above the center of the top opening in the pair of contiguous packaging containers 3 that are intermittently transferred and stopped on the conveyor 5.
• the air pipe 31 extends between and connects the hot air nozzles 27, 29 and the compressor 37. Ahead of or behind the air pipe 31 are provided the heater 33, the dust removing filter 35, and the butterfly valve. Thus, the air that is compressed by the compressor 37 and then heated by the heater 33 to raise its temperature (i.e. the hot air) is continuously blown into the container interior from the hot air nozzles 27, 29.
• the temperature setting for the heater 33 and the internal pressure (flow rate) for the air pipe 31 can be infinitely adjusted by operation of a controller and the butterfly valve, respectively.
• Fig. 1 generally illustrates a controller 34 or other suitable mechanism for effecting adjustment of the temperature of the compressed hot air that is blown into the container interior. Therefore, the temperature and the pressure (flow rate) of the hot air blown into the container interior can be set at the desired value.
• the filling device 11 is provided with filling nozzles 41, 43, lifters (not specifically illustrated), metering pumps 45, 47, a tank 49, and several connecting pipes 51, 33.
• the filling nozzles 41, 43, the lifters, and the metering pumps 45, 47 are provided in two places, respectively.
• the filling nozzles 41, 43 are each located so as to be approximately above the center of the top opening in the pair of contiguous packaging containers 3 which are intermittently transferred and stopped on the conveyor 5.
• the lifters are provided under the bottom 3a of the packaging container 3, with each being positioned in opposing relation to one of the filling nozzles 41, 43, respectively.
• the empty packaging containers 3 transferred from the sterilizing agent removing device 23 are first lifted by the lifters to a position where the inside surface (bottom inside surface) of the bottom 3a of the container is nearly in contact with the filling nozzle 41, 43.
• the metering pumps 45, 47 are operated to draw a predetermined amount of liquid food from the tank 49.
• the metering pumps 45, 47 then effect the delivery of the food product to the container.
• the container interior is filled with a predetermined amount of the food product through the filling nozzles 41, 43, with the lifters gradually lowering the packaging containers 3 so that the level of the food product fed into the container interior is always just under the filling nozzles 41, 43.
• the sealing device is provided with a top heater and a top pressing device.
• the top panels of the filled packaging container 3 that is transferred by the conveyor 5 is heated by the hot air passing through the top heater so that the thermoplastic layer reaches the proper sealing temperature.
• the top pressing device presses the top panels to bond them to one another through the thermoplastic layer, and seals the top side 3b of the packaging container 3 so that a closed bottom is provided.
• the packaging container 3 filled with food is passed through the dating device and the discharge conveyor before being delivered as a final product from the packaging system 1.
• the section of the system ranging from the forming device 7 to the sealing device, including the conveyor 5, is covered with a casing (not specifically illustrated) to increase the sterilizing effect.
• the packaging containers 3 that were tested were bottomed type containers, having three different volumes - 250 ml, 500 ml, and 1000 ml.
• the operating conditions set for the conveyor 5 involved: intermittently transferring packaging containers 3 in contiguous pairs in approximately 1.2 sec, and stopping them for approximately 0.6 sec. between transfers. Thus, the containers were moved forward for 0.6 sec. and then stopped moving for 0.6 sec. During the 0.6 sec. time period when the containers on the conveyor stopped moving, sterilizing agent was deposited into the containers at the sterilizing agent depositing device 19, sterilizing agent was removed from the containers at the sterilizing agent removing device 23 and liquid food product was filled into the containers at the filling device 11, respectively.
• the air flow rate was set at 80 Nm 3 /h, and the setting temperature for the heater 33 was adjusted to the container volume of the compressor 37.
• the concentration of residual hydrogen peroxide was measured at six points in total, with three points inside of each packaging container 3 being sampled at random.
• the results of the tests involving packaging containers 3 of 1000 ml confirmed that, when the setting temperature for the heater 33 was at 280 °C or 300°C, 0.01 ppm of hydrogen peroxide were left at three of the six measuring points. However, it was discovered that when the temperature is set at 320°C, the hydrogen peroxide was completely removed and not left at all at the six measuring points.
• the setting temperature for the heater when this packaging system 1 is operated under the described conditions, must be 320 °C or higher for a container volume of 1000 ml, and 280 °C or higher for 500 ml and 250 ml container volumes.
• the compressed hot air blown into the container interior thermally decomposes the hydrogen peroxide in the hydrogen peroxide-containing solution deposited into the container interior to form water and oxygen, and rapidly vaporizes the water after decomposition.
• the reason why the proper setting temperature for 500 ml size packaging containers, which is 280 °C or higher, is the same as that for 250 ml size packaging containers is that, for the 250 ml size, the average flow rate for the hydrogen peroxide to be injected into the container interior is set at a value lower than (2/3 times) that for 500 ml.
• a hydrogen-peroxide containing solution having a hydrogen-peroxide concentration in the range of 0.05 - 0.20 wt. %, preferably 0.07 - 0.15 wt. %.
• the present invention provides a simple method and device that blows compressed hot air at the proper temperature while also allowing the hydrogen peroxide to be thoroughly removed from the container interior in a short period of time.
• all that is required to effect such an advantageous result is a simple and compact provision consisting of a sterilizing agent depositing device 19 that deposits a hydrogen peroxide-containing solution into the container interior and a sterilizing agent removing device 23 that removes the deposited solution by means of compressed hot air before filling the container with food.
• the packaging system 1 that continuously fills food into packaging containers 3 which are intermittently and continuously transferred by the conveyor 5
• the hydrogen peroxide can be thoroughly removed from the container interior in a short time period.
• hot air at the proper temperature suited for the volume of the packaging container can be blown into the container interior and the same device can be used with more than one type or size of packaging container 3 to reliably remove hydrogen peroxide.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Apparatus For Disinfection Or Sterilisation (AREA)

Applications Claiming Priority (4)

Publications (3)

Family

ID=13484012

Family Applications (1)

Country Status (5)

Families Citing this family (7)

Family Cites Families (9)

• 1996
  • 1996-03-27 JP JP7225596A patent/JPH09254936A/ja active Pending
• 1997
  • 1997-03-27 WO PCT/US1997/004931 patent/WO1997035768A1/en not_active Ceased
  • 1997-03-27 DE DE69715399T patent/DE69715399T2/de not_active Expired - Lifetime
  • 1997-03-27 EP EP97917028A patent/EP0900165B1/de not_active Expired - Lifetime
  • 1997-03-27 AU AU25487/97A patent/AU2548797A/en not_active Abandoned

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