Method and apparatus for container conveyance in germ-free filling/packaging system

Abstract: A rotatable partition (1) is provided to establish a sealing relationship between each pair of successive stages in a germ-free filling/packaging system or between the end stages and the outside air. A hollow cylinder (5) containing the rotatable partition is provided with an inlet (30) through which germ-free gas flows in and an outlet (31) through which germ-free gas flows out. The floor of a germicide mist fixing station (44) and/or a germicide removing station (46) and/or conveyor arms (3) are provided with heater elements (60).

Description: The present invention relates to provide in germ-free filling/packaging system adapted to sterilize containers and then to fill these containers with germ-free food or drink, a method and apparatus provided between each pair of successive processes or within each process, to convey the containers and simultaneously to achieve adequate sterilization while maintaining a sealed condition within each process. It is well known from Japanese Patent publication Nos. 1980-3218 and 1980-4618 to perform sterilization, filling and sealing of the containers within a germ-free chamber while conveying these containers. According to said Patent Publication No. 1980-3218, the germ-free chamber is maintained at a pressure slightly higher than that of the outer air and thereby the outer air is prevented from entering thereinto. However, It is difficult to maintain the inner pressure of the germ-free chamber constantly such a high level and, once the inner pressure has dropped, it is impossible to convey the following container into the germ-free chamber. Thus this system of prior art is disadvantageous in that continuous processes can not be carried out. Said Patent Publication No. 1980-4618 discloses a system adapted to establish a sealing relationship between the germ-free chamber and the outer air by utilizing liquid. However, there has been no solution to convey the containers into and within the germ-free chamber, or to convey the containers out of the germ-free chamber after being filled with food or drink, or to maintain the condition of the germ-free chamber. The inventor of the present application has disclosed a countermeasure to solve these problems in Japanese Disclosure Gazette No. 1986-203322. This solution is to provide rotatable partitions adapted for sealing the respective processes from the outer air and the containers are conveyed by recesses formed in these rotatable partitions for this purpose. Accordingly, such solution is certainly advantageous in that the respective processes are always isolated from the outer air and the outer air is prevented from directly flowing into the respective processes. However, this system of prior art utilizing the rotatable partitions has been found to be inadequate in the sealing effect against the outer air. Specifically, germicide in the sterilizing process is apt to leak out in the outer air and thereby to injure operator's health. Inversely, germs in the outer air sometimes enter into the respective process, destroying the germ-free condition maintained therein. Additionally, according to the inventor's Japanese Disclosure Gazette No. 1986-203322, H₂O₂ mist which has been used in the sterilizing chamber for sterilization is then dried in the drying chamber by hot air. However, H₂O₂ mist is apt to cling to the conveyor means in the sterilizing chamber and, therefore, operation of removing this is required. Further-more, sometimes H₂O₂ mist is condensed and accumulated on the conveyor means. In such case, droplets of germicide cling to the containers also and operation of removing said droplets is required. Also in the drying chamber, the individual containers come into contact with the same locations of this chamber, so germicide is apt to be condensed on these locations. With a consequence, the drying chamber can not provide the expected function, sometimes leaving a certain quantity of germicide still not dried. Moreover, when conveyor arms are used as the conveyor means in the drying chamber, these conveyor arms intercept hot air streams and thereby obstruct the effective drying. An object of the present invention is to protect the containers against contamination due to germicide agglutinated or left clinging thereto which might otherwise occur during conveyance of these containers in the germicide fixing station or the germicide removing station of a germ-free filling/packaging system. According to a first aspect of the present invention, there is provided a method for the conveyance of containers in a germ-free filling/packaging system having a germicide mist fixing station for sterilising of the containers and a germicide removing station for drying of germicide clinging to the containers, the method being characterised in that, in the germicide mist fixing station and the germicide removing station, the containers are held by respective comb-teeth formed in respective conveyor arms as the conveyor arms perform a box motion and are thereby conveyed to subsequent processes, and, during such conveyance of the containers, the floor or at least one of the germicide mist fixing station and the germicide removing station and/or the combteeth of each conveyor arm is heated so as to prevent germicide from being condensed on areas along which the containers come into contact with the floor or comb-teeth. According to a second aspect of the present invention, there is provided apparatus for container conveyance in a germ-free filling/packaging system, the apparatus being characterised in that the floor of at least one of a germicide mist fixing station and a germicide removing station and/or a conveyor arm is provided with heater elements arranged to heat and dry the areas along which the containers come into contact with the floor and/or the conveyor arm. The method and apparatus for container conveyance in the germ-free filling/packaging system as has been mentioned just above provide an effect as following: in the mist fixing station, germicide clinging to the conveyor arm and the container carrying floor can be effectively evaporated to avoid inconveniences which might otherwise be encountered, e.g., condensation of germicide mist on the containers, droplets of germicide accumulated on the floor of the mist fixing station and corrosion of the equipment components due to such germicide droplets. Also in the germicide removing station, heating effect is assured even in the areas along which the containers come into contact with the conveyor arm and the container carrying floor, and thereby drying is sufficiently done to eliminate any quantity of germicide remaining not dried. In this way, the container conveyance is performed in a highly hygienic manner without any deterioration of food or drink due to residual germicide. The above and other objects of the present invention will be seen by reference to the description taken in connection with the accompanying drawings, in which: Fig. 1A is a plan view showing a germ-free filling system according to the present invention; Fig. 1B is a plan view of a block 50 shown in Fig. 1A; Fig. 2 is a sectional view taken along a line II - II in Fig. 1A; Fig. 3A is a front view showing, partially in a section, a mechanism adapted to drive a conveyor arm back and forth; Fig. 3B is a left side view corresponding to Fig. 3A; Fig. 4 is a perspective view illustrating a relationship of a rotatable partition with the conveyor arm; Fig. 5A is a front view showing, partially in a section, a mechanism adapted for laterally driving the conveyor arm; Fig. 5B is a right side view, partially in a section, similar to Fig. 5A; Fig. 6A is a perspective view showing the first embodiment of the germ-free conveyor means in the block 50; Fig. 6B is a plan view corresponding to Fig. 6A; Fig. 7A is a perspective view showing the second embodiment of the germ-free conveyor means in the block 50; Fig. 7B is a sectional view corresponding to Fig. 7A; Fig. 7C is a sectional view showing a variation of the embodiment shown by Fig. 7A; Fig. 8A is a perspective view showing the third embodiment of the germ-free conveyor means in the block 50; Fig. 8B is a perspective view showing, partially in a section, the germ-free conveyor means of Fig. 8A; Fig. 9A is a plan view showing the fourth embodiment of the germ-free conveyor means in the block 50; Fig. 9B is a sectional view corresponding to Fig. 9A; Fig. 10 is a side view illustrating a relationship of heat pipes 60 with the conveyor arm; Fig. 11 is a sectional view showing an arrangement of an electric heater 61 disposed under the heat pipes 60; and Fig. 12 is a plan view partially broken away, showing an arrangement of the electric heater applied to the underside of the conveyor arm 3. The germ-free filling/packaging system will be described in reference with Fig. 1. Said germ-free filling/packaging system 40 comprises a container supply station 42, a germicide mist fixing station 44 serving to sterilize the containers, a germicide removing station 46 serving also as a drying chamber, and a filling/sealing station 48 provided for germ-free filling of food or drink. Blocks 50 are respectively provided between the container supply station 42 and the germicide mist fixing station 44, between said germicide mist fixing station 44 and the germicide removing station 46, between said germicide removing station 46 and the container filling/sealing station 48, and at outlet of said container filling/sealing station 48. The block 50 at the outlet of the container filling/sealing station 48 may be replaced by means to regulate a pressure within said container filling/sealing station 48 at a level which is a positive with respect to the atmospheric pressure or means to breathe germ-free air out and thereby to achieve air-tightness. As seen in Fig. 1B, each of the blocks 50 defines a cylindrical space 52 having two openings 54, 56 respectively formed at front and rear sides thereof. A rotatable partition 1 is provided within said cylindrical space 52. Said rotatable partition 1 includes four container transporting recesses 2 formed therein at angular intervals of 90 degrees so that the individual containers may be received and discharged by the respective container transporting recesses 2. Accordingly, the rotatable partitions 1 are intermittently rotated by 1/4 revolution within the respective cylindrical spaces 52 to seal the respective blocks 50 interposed between the respective process. There are provided between each pair of the adjacent rotatable partitions a comb-toothed conveyor arm 3 adapted for so-called box-motion and a guide rail 20 operatively associated with said conveyor arm 3 so that the germ-free packaging container 22 is held between a comb-tooth 3a of said conveyor arm 3 and said guide rail 20 and thus conveyed. Now said box-motion of the conveyor arm 3 indicated by arrows in Fig. 4 will be discussed, and, first, the mechanism for driving the conveyor arm 3 back and forth will be considered. As shown by Fig. 3B, the conveyor arm 3 is supported by a ball bearing 6 back and forth slidably with respect to a shaft 5 of bearing brackets 4. As seen in Fig. 3A, a drive force provided from a drive mechanism not shown is transmitted through bevel gears 12, 13 to a ball bearing 14 carried by said bevel gear 13, which ball bearing 14, in turn, rotates a shaft 8 by engagement with splines 15 formed around said shaft 8. Rotation of this shaft 8 causes a pinion 16 mounted on said shaft 8 to be rotated and thereby a rack 17 mounted on the conveyor arm 3 adapted to be engaged with said pinion 16 drives the conveyor arm 3 back and forth. It should be understood that the shaft 8 is movable also laterally as the bearing brackets 4 are laterally moved, because of the above mentioned arrangement such that the bevel gear 13 is provided with the ball bearing 14 and the shaft 8 is provided with the splines 15. Then the mechanism to drive the conveyor arm 3 laterally will be considered in reference with Figs. 5A and 5B. The bearing brackets 4 are laterally movable along a rail 7 and the rotatable shaft 8 rotatably extends through said bearing brackets 4. It should be noted here that the rotatable shaft 8 is provided with suitable stopper means allowing said shaft 8 to be laterally moved integrally with said brackets 4. The bearing brackets 4 are respectively provided in respective bottoms thereof with grooves 9 in which the associated rollers 10 are movably received. Each of said rollers 10 is mounted on a rotatable arm 11 at an end remote from a shaft 11a associated with said rotatable arm 11. Rotation of this shaft 11 causes the roller 10 to move along said groove 9, thereby causes the bearing brackets 4 to be laterally moved and thereby causes the conveyor arm 3 also to be laterally moved. Said back and forth movement and lateral movement of the conveyor arm 3 may be combined to provide a box-motion of the conveyor arm 3 as indicated by arrows in Fig. 4. More specifically, the conveyor arm 3 moves forward into engagement with the container to convey it, and moves backward, after a conveyance has been done over a predetermined distance, to its home position. Such motion is repeated. As shown by Fig.4, each of the container transporting recesses 2 is provided in its side wall with a horizontal slit 18 so that the conveyor arm 3 may partially enter into this recess 2 along said slit 18 to deliver the container into this recess 2 and simultaneously to seal upper and lower portions of this recess 2 from the outer air, thus preventing air leakage. Referring to Fig. 2, reference numeral 20 designates a guide for a rear side of the container and reference numeral 21 designates a frame surface on which the container is slidably moved. Germ-free conveyor means are provided in the respective blocks 50 which are, in turn, interposed between the successive processes in the above mentioned germ-free filling/packaging system. Said germ-free conveyor means may be constructed so that germicide once fixed to the respective container transporting recesses 2 is removed by germ-free gas during intermittent travels of said container transporting recesses 2 as each rotatable partition 1 is intermittently rotated or so that said container transporting recesses 2 are effectively made germ-free by using germicide containing air stream or germ-free gas stream. Figs. 6A and 6B show the first embodiment of the germ-free conveyor means in which the cylindrical space 52 is provided in its top with a gas inlet 30 and in its bottom with a gas outlet 31. It should be understood that a space surrounded by a cylindrical wall 51 is meant by the term " cylindrical space 52 ". Bottom wall of the container transporting recess 2 is provided with a plurality of perforations 32 through which germ-free gas supplied from above may flow out from this recess 2. Circumferential elongate chambers 33, 34 are formed around the gas inlet 30 and the gas outlet 31, respectively, so that these chambers 33, 34 may be opposed to each other with interposition of said perforations 32 as the rotatable partition 1 rotates. As has already been explained, the respective rotatable partitions 1 are intermittently rotated by 1/4 revolution for each cycle while maintaining the sealing relationship between the successive processes and the respective container transporting recesses 2 spaced by 90 degrees from one another in each rotatable partition 1 and successively supplied from the gas inlet 30 with germ-free gas. Germ-free gas may be gas containing therein germicide, for example, H₂O₂ or hot air approximately at a temperature of 100°C. The present embodiment includes the chambers 33, 34 formed around the gas inlet and outlet, respectively, adapted to facilitate flowing of germ-free gas through the respective container transporting recesses 2 as the rotatable partition 1 relates and is advantageous in that each recess 2 can be exposed to such gas flow for a time as long as possible. In this manner, each recess 2 is adequately exposed to said germ-free gas while this recess 2 travels from the one opening 54 to the diametrically opposed opening 56, passing between the chamber 33 formed in fluid communication with the gas inlet 30 and the chamber 34 formed in fluid communication with the gas outlet 31, as the rotatable partition 1 rotates, and thereby the interior of this recess 2 is brought into a germ-free or dried condition. Making the container transporting recesses 2 germ-free contributes to prevent the germ-free condition of the subsequent process from being adversely affected by the preceding process. And making the container transporting recesses 2 well dried contributes to avoid leakage of germicide into the subsequent process or into the outer air. Figs. 7A, 7B and 7C illustrate other embodiments of the germ-free conveyor in the respective blocks 50. According to these embodiments, the respective container transporting recesses 2 are supplied with germ-free gas at an intermediate position in the travel course of the container 22 from the opening 54 serving to receive the container 22 to the diametrically opposite opening 56 serving to discharge the container 22 and another intermediate position in the travel course of the container 22 from said opening 56 to said opening 54. Fig. 7B illustrates an embodiment in which a disc provided with perforations 35a is mounted under the chamber 33 which is formed in fluid communicating relationship with the gas inlet 30 and a similar disc having perforations 35b is placed above the chamber 34 formed in fluid communicating relationship with the gas outlet 31 so that a germ-free gas can directly flow into the respective container transporting recesses 2. Fig. 7C illustrates an embodiment similar to that shown by Fig. 7B except that the container transporting recesses 2 are formed in a lower portion of the rotatable partition 1 and, to supply germ-free gas through the disc perforations 35a into the respective recesses 2, the rotatable partition 1 itself is provided with perforations 36 adapted to be aligned with said disc perforations 35a. Figs. 8A and 8B illustrate another further embodiment of the germ-free conveyor means for each block 50, in which the gas inlet 30 and the associated chamber 33 are provided laterally of the rotatable partition 1 and a cylindrical wall 51 surrounding the cylindrical space in each block 50 is partially formed with perforations 35a through which germ-free gas flows from the chamber 33 into the respective container transporting recesses 2. Figs. 9A and 9B illustrates still another embodiment of the germ-free conveyor means characterized by that germ-free gas can flow into the respective container transporting recesses 2 through all over the top and flow out from said recesses 2 through all over the bottom of the cylindrical space 52. In this way, the respective containers are continuously exposed to germ-free gas as long as the containers 22 exist within the germ-free conveyor means. In this embodiment, a relatively wide cylindrical gap 52 is defined between the rotatable partition 1 and the cylindrical wall 51 surrounding the latter, and the respective container transporting recesses 2 are so configured to partitially carry the respective containers 22. The respective embodiments of the germ-free conveyor means as have been mentioned hereinabove may be selectively disposed depending on the locations at which the rotatable partitions 1 are to be disposed. For example, when it is desired to establish a sealing relationship between the outer air and the sterilizing process, the rotatable partition may be provided either only on the side of this process from which the germicide mist can leak into the outer air or only on the side from which the outer air can enter into this process. Of course, the germ-free conveyor means may be provided on both sides of such process. Also when it is necessary to assure a sealing relationship between the outer air and the process to be maintained germ-free, the germ-free conveyor means may be selectively disposed like the above mentioned case in which the sealing relationship must be established between the outer air and the sterilizing process. It is not necessarily essential that the gas inlet 30 occupies an upper position and the gas outlet 31 occupies a lower position, namely, in the germ-free conveyor means used to intercept germicide mist, it is preferred to dispose the gas inlet 30 above and to dispose the gas outlet 31 below, since germicide may partially form droplets around the gas outlet 31. Provision of suction means in association with the gas outlet 31 is optional. Another aspect of the present invention relates to germ-free conveyor means having heater elements in both the germicide mist fixing station and the germicide removing station. The construction is such that respective floors of the germicide mist fixing station 44, the germicide removing station 46, and the conveyor arms 3 are heated to avoid condensation of germicide which might otherwise occur in the areas where said floors and the comb-teeth 3a come into contact with the containers 22. As shown in Figs. 10 through 12, the respective sterilizing processes or germ-free processes are provided on their bottoms with several heat pipes 60 extending along a direction in which the conveyor arms 3 having the comb-teeth 3a perform their conveying function. In this specific embodiment, the heater elements are provided so as to be held out of direct contact with the containers 22, in view of a fact that the containers are made of synthetic resin. Referring to Fig. 11, reference numeral 61 designates an electric heater, and heat generated as this electric heater 61 is energized is conducted through a heat pipe holder 62 to the heat pipes 60. The heat pipes 60 may be made of suitable anticorrosive material such as SUS and heat medium flowing in the pipes may be alcohol or like. The heat pipe holder 62 may be made of material having a high heat conduction such as aluminum and may be heated to a temperature of 60 °C to 80°C on the surface of each heat pipe 60. As shown in Fig. 12, a flat electric heater 63 such as silicon rubber heater is applied onto the underside of the comb-toothed conveyor arm 3 and thereby the conveyor arm 3 also is heated to a temperature of 60°C to 80°C. By heating the floors of the respective stations and the conveyor arms 3 in this manner, the condensed germicide mist (e.g., H₂O₂ ) on the areas where said components come into contact with the containers is rapidly dried and thereby said germicide mist is prevented from clinging to said areas. The illustrated embodiment is advantageous also in that the area over which said floors come into contact with the containers 22 can be effectively reduced by said floors formed by said heat pipes and, in consequence, germicide mist can be distributed all over said floors.

Claims: A method for the conveyance of containers (22) in a germ-free filling/packaging system having a germicide mist fixing station (44) for sterilising of the containers and a germicide removing station (46) for drying of germicide clinging to the containers, the method being characterised in that, in the germicide mist fixing station and the germicide removing station, the containers are held by respective comb-teeth formed in respective conveyor arms (3) as the conveyor arms perform a box motion and are thereby conveyed to subsequent processes, and, during such conveyance of the containers, the floor of at least one of the germicide mist fixing station and the germicide removing station and/or the combteeth of each conveyor arm (3) is heated so as to prevent germicide from being condensed on areas along which the containers come into contact with the floor or comb-teeth. Apparatus for container conveyance in a germ-free filling/packaging system, the apparatus being characterised in that the floor of at least one of a germicide mist fixing station (44) and a germicide removing station (46) and/or a conveyor arm (3) is provided with heater elements (60) arranged to heat and dry the areas along which the containers come into contact with the floor and/or the conveyor arm. Apparatus according to claim 2, wherein the floor of the germicide mist fixing station or the germicide removing station is provided with a heat pipe (60) and there is provided a heater (61) in proximity with the heat pipe. Apparatus according to claim 2, wherein each of the conveyor arms is provided with a heating plate (60). Apparatus according to claim 2, further including an air-tight cylinder (51) having two openings (54,56) and disposed between each pair of successive stages of the germ-free filling/packaging system or between the end stages and outside air; a rotatable partition (1) rotatably mounted within the cylinder; recesses (2) formed in the rotatable partition to transport respective containers from the one opening to the other; and an inlet (30) and outlet (31) formed in the air-tight cylinder for gas flow to remove germicide from the recesses or to sterilise the recesses.

Inventors: HATANAKA KOICHI, IDE TAKEO, HATANAKA, KOICHI, IDE, TAKEO
Applicants: SNOW BRAND MILK PROD CO LTD, SNOW BRAND MILK PRODUCTS & CO., LTD.
Application year: 1989
Main classification: B65B55
IPC codes: B65B55