Patent Grant
6925780
This invention relates to a method of aseptically filling containers, apparatus for the aseptic filling of containers, to containers incorporating an inlet assembly with which the method may be used, and to a plug and gland port for such containers.
The filling of pre-sterilized containers in an aseptic manner is known and various systems are employed which utilize different filling apparatus, different containers, and different sterilization techniques. Specifically, the container to be filled is produced in a manner which ensures that the interior of the container is sterilized during manufacture. During the filling procedure an inlet into the container is opened and a filling nozzle used to fill the container with a selected flowable material. The inlet is then sealed to thereby contain the flowable material within the container until dispensing is required. To ensure that the contents of the container is kept as free of contaminating bacteria and other micro organisms as possible it is essential that the act of filling the container does not in itself introduce contaminants into the interior of the container. Also, the resealing of the container after it is filled must be done in such a way that a proper seal is achieved so that contamination does not take place during transportation or storage.
Various prior art patents have addressed the aforementioned problems and reference may be made to U.S. Pat. No. 4,805,378 (Anderson), U.S. Pat. No. 2,930,170 (Holsman et al), U.S. Pat. No. 4,542,530 (Thomas et al) and U.S. Pat. No. 4,672,688 (Kalkipsakis). These prior art patents describe systems which are successful to a greater or lesser extent. However, the prior art systems do suffer from certain deficiencies, at least under some filling circumstances.
For example, U.S. Pat. No. 4,805,378 discloses an arrangement in which a flap is positioned across the mouth of the filling inlet, which provides some measure of obstruction to the flowable material entering the container. Current food processing plants can produce product at a rate of in excess of 20,000 liters per hour and it is important that the container is able to receive a product at this flow rate in order to avoid providing multiple head filling systems and the like. To achieve filling rates of this order relatively large diameter filling inlets are required into the containers and the flap system disclosed in U.S. Pat. No. 4,805,378, limits the diameter and flow rate into the container. Also, for highly viscous materials, and for materials which contain solid particles, the flap system is not always completely suitable.
The U.S. Pat. No. 4,805,378 discloses a container which is filled via an upstanding plastics collar, at one end of which a first flange is heat fused to the flexible plastic sheet wall of the container surrounding a filling opening in the container and, at a second flange at the opposite end of the collar, a rupturable sheet plastics membrane is also heat fused. The sheet plastics membrane, which is heat sterilized in manufacture but which most likely would be recontaminated externally before filling, is resterilized immediately prior to filling by a fluid (for example pressurized steam) after being brought into engagement with a filling head of an aseptic filler. In the described method, an incision tool forming part of the filling head, sterilized along with the exterior of the membrane, is advanced to cut the membrane then withdrawn to enable admission of the liquid to be packaged through the collar and through gaps formed between the flap partially heat fused to the flange inside the container.
As discussed in U.S. Pat. No. 4,805,378, the cutting of the resterilized membrane involves making a pair of straight incisions, crossed at right angles passing through the center of the membrane and extending radially outward to a point just inside the outer flange of the upstanding plastics collar. Accordingly, as the liquid or liquid-like product flows into the bag to fill it, the four cut tips or “reversed petals” of the membrane turn inwardly with the flow and extend towards the inner and end of the collar where it is connected to the bag in the region that is subsequently sealed closed as described. There are occasionally experienced instances of unreliability with this arrangement in that the four petals of the top membrane, since they remain on the filled sealed package, are difficult to clean underneath to remove remnants of the packaged product inside of the collar during the flushing cycle. Also, the petals tend to reduce the flow rate of the product into the container during filling which can be disadvantageous from a production point of view with viscous or particulate containing products.
There is furthermore a risk that the tips of the petals might wrap underneath the inside corner of the flange and be caught up in the subsequent final heat sealing operation. If this were to happen there would be a potential for a leakage path to bypass the seal or, at least, a potential source of failure of the seal. Accordingly, the axial height of the collar should be sufficient in relation to the diameter opening to prevent this possibility. In use commercially, the diameter of opening as disclosed in the Anderson patent is known to be in the range of 16–32 mm. With the desired future extension of the size of opening up to 60 mm or 70 mm, using the arrangement disclosed in the patent would require a corresponding increase in axial height of the collar. There would be no other need to increase the height of the collar other than to ensure that the cut petals of the membrane could not enter the sealing region, but such a high profile of collar would be unacceptable in general to fillers and end users of the package alike. It is therefore an object of this invention to provide a method which will overcome the disadvantages associated with a rupturable outer membrane.
Typically, the aforementioned packaging systems are used with high acid products, predominantly tomato paste, orange juice and juice concentrates. It is also known to use this type of packaging system with low acid products, such as milk, cream and egg pulp for example.
Manufacturers are beginning to take advantage of processing system developments and market acceptance, for an increased range of particulate and concentrate products. The types of products currently being considered for packaging are pineapple chunks, diced tomatoes, ready prepared meals, meat sauces, fruit particulate, and various other similar type products. These products come in a range of different acidities and larger diameter filling nozzles are generally required in order to fill containers at the required flow rate and accommodate larger particulate sizes.
Containers having capacity of 1,000 liters or more are typically used for bulk packaging and with increased capacity of processing plants there is currently a need for a high capacity, highly aseptic packaging system that utilizes a large diameter filling nozzle and provides a high quality seal after filling and which can be used with low acid products.
According to the invention there is provided a method of aseptically filling an internally sterilized container having a transfer port which comprises a tubular body which is sealed to the wall of the container and defines a flow passage therethrough, and a sealing plug engaged into the passage, the tubular body having an annular outer sealing face thereon which surrounds the flow passage, the method comprising the steps of:
The method may include the further steps of:
The method may further include the steps of:
The method may include the further steps of:
The method may include the further steps of:
The step of cleaning the peripheral outer surfaces of the plug may be achieved by introducing a sterilization fluid into the sterilization chamber with the plug partially inserted into the flow passage in the tubular body.
The method may include the steps of sealing the plug to the tubular body during or after the plug has been reinserted into the tubular body. The sealing may be achieved by welding the plug in to the tubular body. The welding may be done using high temperature sterilization fluid, preferably steam.
According to a second aspect of the invention there is provided a sterilization and filling apparatus for aseptic filling of sterile containers having a filling nozzle comprising a tubular body with a flow passage therethrough and a plug for closing the flow passage, at least the tubular body having an annular sealing face thereon, the apparatus comprising:
Preferably the sterilization and filling head includes an inner sealing ring which is co-axial with said outer sealing ring and spaced inwardly therefrom to define an annular space therebetween, said annular space forming said sterilization chamber, said inner sealing ring being engageable with a sealing face provided on the plug.
The plug extractor may comprise one or more gripping jaws adapted to grip the plug and extract it from the tubular body into the cavity. The jaws may be mounted to a ram, which is moveable in an axial direction towards and away from the plug, the jaws being moveable between gripping and release positions.
Preferably the jaws automatically move to a gripping position when the ram moves in direction away from the plug, and move into the release position when the ram moves towards the plug. The ram may be adapted to drive the plug into the tubular passage after the container has been filled.
The sterilization and filling head may be adapted to shut off the flow of filling material into the container prior to the plug being fully inserted into the tubular passage. The sterilization and filling head may, furthermore, be adapted to clean the plug with sterilization fluid when the plug is partially re-inserted back into the tubular passage.
A further aspect of the invention provides an aseptic container adapted to be filled with a flowable material, the aseptic container having a filling opening comprising a tubular body having a flow passage therethrough, and a plug for sealing the flow passage, the plug having gripping formations on the outer face thereof, and retaining means or formations thereon for cooperatively or cooperatively locking the plug into the flow passage.
Preferably said gripping formations will allow the application of an axially directed force to be applied to the plug to remove or re-install the plug into the filling opening. Alternatively the gripping formations will allow the applications of a rotational force to be applied to the plug to remove or re-install the plug into the filling opening.
Preferably the plug is removed and reinstalled into said opening by axial means, preferably of a slide or interference fit. Alternatively the plug and opening may include a screw thread or cam or bayonet locking means.
Optionally the plug may be cup shaped having an end wall and a cylindrical skirt depending from the end wall, the end wall adapted to be outermost when the plug is inserted into the flow passage. The gripping formations may be formed on the end wall and project in a direction which is opposite to that in which the skirt extends from the end wall. The gripping formations may take the form of a head which stands proud of the end wall. The head may be undercut to provide purchase for the gripping jaw which is adapted to extract the plug from the flow passage. The locking formations may comprise a radially outwardly projecting annular rib formed on the plug, said rib being adapted to locate behind a shoulder, end face or within a groove formed in or adjacent the flow passage. The flow passage and/or the plug may have an annular seal therein adapted to seal with a plug inserted into the annular passage.
The plug and/or the tubular body may both be formed of a thermoplastic material adapted to bond together under temperatures of between about 130° C. and 180° C.
The plug and the tubular body may be sealed together during manufacture. That seal may be mechanically rupturable, or it may be adapted to be weakened under temperatures of between about 130° C. and 180° C. thereby providing an arrangement for simplified extraction of the plug after it has been sterilized by a high temperature sterilization fluid.
According to a further aspect of the invention there is provided a plug and gland port for use on an aseptic container, said port comprising:
Preferably the annular recess on the plug is at least partially filled with a sealing ring. The sealing ring may be in the form of a low melt sealant deposited in said recess. The low melt sealant may comprise a material such as a polyolefin elastomer.
Preferably the rib or lip on the cylindrical inner wall is spaced a first distance away from the operatively outer end face of the tubular body. Preferably the annular recess on the recess on the plug is spaced a second distance away from the operatively outer end face of the plug, said second distance being less than said first distance.
The plug may have a second annular recess formed around the periphery thereof, said annular recess being spaced from the first annular recess, the second annular recess being spaced a distance away from the operatively end face of the plug by a distance which is substantially the same as the distance which is substantially the same as the distance which the rib or lip is spaced away from the operatively outer end face of the gland so that when the rib or lip is located within the second annular recess the operatively outer end faces of the gland and the plug are substantially flush with each other. Prior to filling the container the gland and plug may be welded together.
The rib or lip may have a generally triangular form in cross section so as to provide a chamfered or severed face in both an outwardly facing direction and an inwardly facing direction to allow for simplified engagement and disengagement of the plug with the gland.
These and further features of the invention will be made apparent from the description of preferred embodiments thereof given below by way of examples. In the description reference is made to the accompanying drawings, but the specific feature shown in the drawings should not be construed as limiting on the invention.
In this specification and claims, where the words “comprising”, “comprised” or words derived therefrom are used, those terms are to be interpreted inclusively rather than exclusively.
Turning initially to
Turning to
In order to commence the filling operation the sterilization and filling head 39 and the upper surface of the transfer port 14 are brought into engagement with each other, as shown in
The sterilization and filling head is provided with a sterilization fluid supply line 54 which leads into the sterilization chamber 44 and which is controlled by an inlet valve 56. A sterilization fluid discharge line 58 leads from the sterilization chamber 44 and is controlled by an exit valve 60. The sterilization fluid will generally comprise steam supplied under pressure at a temperature of between 130° C. and 180° C.
The inner sealing ring 42 is formed on the end of a sliding sleeve 64, which is slideable along axis 52 towards and away from the transfer port 14. The sliding sleeve 64 serves as a control valve for controlling the flow of a flowable product into the container, as is described in more detail below.
An axially moveable plunger or ram 62 is moveable along axis 52 within a cylindrical cavity 66 formed within the sleeve 64. The ram 62 has a series of gripping jaws 70 fitted to the end thereof which are spring loaded by means of a spring 74. The gripping jaws 70 are adapted to engage with the head 30 of the plug 22 in order to pull the plug 22 out of the tubular passage 19.
The sterilization and filling head 39 is provided with a product supply passage 76 through which product to be filled into the container 10 is fed through the head. When the sleeve is retracted to the position shown in
In use, the apparatus operates substantially as follows. Firstly, the tubular body 16 is brought into engagement with the outer sealing ring 40 so that the blade edge 48 embeds into the sealing face 34. The tubular body 16 will be held under pressure against this blade edge 48 for the entire filling process so that a seal will be maintained. Simultaneously the inner blade edge 50 will bed into the sealing face 38 of the plug 22. At this stage the sterilization cavity 44 will be a sealed cavity. It will be noted that the outer sealing ring 40 and the inner sealing ring 42 are located on opposite side of the interface between the tubular body 16 and the plug 22.
In this position, the sterilization head will be tightly clamped against the transfer port 14, and the ram 52 will be lifted causing the jaws 70 to clamp tightly around the head 30, thereby gripping the head 30. Thereafter, the sterilization chamber 44 will be flushed with a high temperature sterilization fluid, typically steam under pressure, to thereby clean all exposed surfaces within the sterilization chamber of any contaminating micro organisms. It should be noted that since the gap between the inner and outer sterilization rings is small, only a small area of the transfer port needs to be sterilized which allows for relatively high temperature sterilization, and short exposure time.
Once sterilization has taken place, and this will generally take between two and five seconds at 150° C., the sleeve 64 will begin moving upwardly and in so doing the plug 22 will be pulled out of the tubular body 16 to the position shown in
The product 78 to be filled into the container will then be supplied through the supply passage 76, the product 78 passing down the flow passage 19 and into the container. It will be noted that the product 78 comes into contact with the underside of the plug 22 as well as the skirt portion of the plug 22. However, the product does not come into contact with any surface which has not been rendered bacteria free as a consequence of either sterilization during manufacture of the container or the sterilization operation referred to above. Thus, the product will in no way be contaminated during the filling process. Provided the product itself is bacteria free at the time it is introduced into the container it should receive no bacteria contamination during the filling process and should therefore be bacteria free within the container.
Once the container is filled, the plug 22 will be replaced into the tubular body 16. This process is shown in
Described below is an arrangement in which the steam which is used to evacuate the sterilization chamber after closure of a plug may be used to clean substantially the entire outer surface of the plug as the plug is being introduced into the passage 19.
In the embodiment shown in
Once the transfer port has been cleaned in the manner described and depicted in
It will be noted that as the ram 52 moves the plug inwardly from the position shown in
It will be noted that towards the lower end of the sleeve 64 a tapered or bevelled sealing surface 88 is formed. This sealing surface 88 is adapted to engage and seal with a seat 90 which is defined within the sterilization and sealing head just above the sterilization chamber. When the sleeve 64 moves to a closed position, as shown in
The hard seal will serve to sever or shear any particulate materials that might otherwise be trapped as the sleeve 64 moves to the closed position.
Clearly there may be many forms of interlocking arrangements which may be provided between the plug and the tubular body. What is important is that no micro passageway exists for the passing of microorganisms between the plug and the tubular body which could otherwise compromise the integrity of the seal provided between the plug and the tubular body.
Alternative arrangements for sealing the plug in the tubular body include some form of welding system. For example, either the plug or the tubular body, or both, may be formed of a material which will soften in the presence of the high temperature sterilization fluid and, when so softened, weld the plug and the tubular body together as the plug is fully inserted into the tubular body to thereby form a seal between these two components which is bacteria proof. It will also be possible to provide a third component which will melt in the presence of the high temperature steam and form a bacteria proof seal between the plug and the tubular body. Some form of hot melt adhesive, for example, coated onto the outer surface of the skirt 26 could achieve the desired welding type seal arrangement. These aspects are discussed in more detail below.
Turning now to
As shown, the sleeve 64 has a sealing surface 88 on the lower end thereof which is adapted to seal with a correspondingly tapered seat 90 on the sealing head. However, seat 90 has been spaced some distance lower than that of the previous embodiment. The sterilization and filling head in this embodiment is provided with an additional sliding seal 92 which is adapted to seal with the outer surface 94 of the sleeve 64 as the sleeve 64 moves down towards its closed position. Thus, as the sleeve moves downwardly from the open position shown in
A further advantage of clearing the surface 28 of the plug 22 with high pressure, high temperature steam is that where it is desired to weld the plug 22 into the tubular body 16 the steam will serve to soften the outer surface of the plug. These two components will then weld together when the plug is in its closed position.
Turning now to
In this embodiment, the sterilization and filling head 98 has a moveable sleeve 100 which is used to lift the plug 22 out of the tubular body 16 and also serves to open and close the filling passage 76. The sleeve 100 is formed of an inner sleeve 102 and outer sleeve 104 which are moveable relative to each other. The inner sleeve 102 has a sharp lower edge 106 which is adapted to engage the sealing surface 38 on the plug 22. The outer sleeve 104 has a bevelled lower edge 108 which is arranged to engage and seal with the seat 90 of the sterilization and filling head. A sliding seal 110 seals the gap 112 between the inner sleeve 102 and outer sleeve 104.
Illustrated in
As illustrated in
In the condition illustrated in
Once sterilization of the portions of the plug 22 and tubular body 16 which are exposed in sterilization chamber 44 has been completed, the inner sleeve 102, ram 62 and plug 22 are retracted together until the outer surface 38 of plug 22 engages the extremity of ramps 79 as seen if
A less preferred retraction scheme is to allow the sleeve 104, sleeve 102, ram 62 and plug 22 to retract in unison in the positions as illustrated in
If desired the circumference of the plug 22 can be decreased or the internal diameter of the sleeve 104 increased so that the plug 22 can move into the sleeve 104 and thus produce a circumferential seal around the plug 22. This will ensure that no part of the surface 38 will be able to hold particulate. To do this an interference fit between the plug 22 and sleeve 104 is preferred but not to a degree which will make the removal of the plug 22 from the sleeve 104 difficult.
Once the outer sleeve 104 has retracted to fully open the passage 76, as illustrated in
Once filling has been completed, the outer sleeve 104, inner sleeve 102 and ram 62 are moved together axially towards the tubular body 16.
As illustrated in
At this point, as illustrated in
The sterilizing fluid will sterilize and flush any food product which remains in the sterilizing chamber 44 to thereby clean the side surfaces of the plug 22 prior to closing.
The exposure to the side surfaces of the plug 22 to the temperature of the sterilizing fluid will soften them thereby helping to create a seal when the plug 22 is pushed into the tubular body 16, as has been described with respect to the embodiment of
Clearly, by providing a facility whereby the inner sleeve 102 may be moved relative to the outer sleeve 104 the plug 22 can be moved to a partially open position, or a fully open position, when the outer sleeve is still in engagement with the seat 90, thereby closing off the filling passage 76.
Likewise, during the closing of the filling passage 76, the outer sleeve 104 can be first moved into a closed position against the seat 90 whilst the plug is in an open, or partially open condition. This will allow the outer surface of the plug 22 to be cleaned with sterilization fluid in a manner described above with reference to the previous embodiment. Clearly the ability to close the filling passage 76 using the outer sleeve 104 whilst being able to independently manipulate the plug 22 may be advantageous in certain circumstances.
Turn now to
Turning first to
A different seal arrangement is shown in the right hand side of the
The embodiment shown in
In the embodiment shown in
The upstanding head 30 of the plug 22 of
In the above described embodiment when sealing of the plug 22 within the gland 16 after the container has been filled, it is best to ensure than contaminants do not enter the container along a pathway defined at the interface between the gland 16 and the plug 22. However, it is also important that the plug 22 is relatively easily removable from the gland 16 for filling purposes. Also, after the container has been filled, it is important that the plug 22 is relatively easily insertable into the gland 16 and, once inserted, is relatively easily removable from the gland 16 in order to decant the contents of the container through the gland 16.
Whilst it is possible to form both the plug 22 and the gland 16 to relatively close tolerances, it is unsafe to rely only on those close tolerances to ensure that the integrity of the seal between the plug 22 and the gland 16 is maintained. Also, if the fit between the plug 22 and the gland 16 is made too tight then insertion of the plug 22 into the gland 16, and the subsequent removal of the plug 22 from the gland 16, are made that much more difficult and can lead to failure of the system either on closing or on opening which, in turn, can lead to loss of contents of the container.
Typically the container and gland 16 will be sterilized internally after manufacture, generally by ionizing radiation. It is essential in a practical sense that the interior of the container is maintained in a sterile condition prior to being filling so that material introduced into the container is introduced into a sterile environment. To aid in this maintenance of sterility the embodiments of
As shown in
The plug 22 includes an end wall 24 and a skirt 26, the outer surface of this skirt 26 being a close sliding fit with the cylindrical wall 18. The plug has an upstanding head 30 which is undercut as shown at numeral 32 so that the plug can be gripped and removed from the gland 16 or reinserted into the gland 16 as required.
The radially outer surface of the skirt 26 has a first annular recess 122 formed therein which is filled with an elastomeric sealing ring 124. The sealing ring 124 is preferably formed of a low melt point sealant such as polyolefin elastomer.
The plug 22 and the gland 16 need not be formed of the same material. The gland may, for example, be formed of polyethylene and the plug may be formed of a material such as polypropylene.
The skirt 26 has a second annular recess 126 formed therein located on the radially outer surface of the skirt near the innermost end thereof.
The wall 18 of the gland 16 has an annular rib or lip 128 formed therein which is best seen in
In the position shown in
If necessary, the plug and the gland may be sealed together, prior to filling, by providing a temporary weld or seal as shown at detail 136 in
After the bag has been filled the plug will be reintroduced into the gland 16, but will be pushed further into the gland, to the position shown in
Preferably the elastomeric sealing ring 124 ring will have been heated during the closing procedure by sterilization steam introduced against the elastomeric sealing ring 124 after the plug has been partially introduced into the gland. This procedure is described in detail above.
After the elastomeric sealing ring 124 has been heated the plug 22 will be pushed further into gland 16 to the position shown in
To remove the plug from the gland 16 the plug will be gripped and pulled outwardly thereby breaking the seal between the sealant 124 and the rib 128.
There may be various alterations to the above-described embodiment without departing from the scope of the invention. For example, there may be a plurality of ribs 128 with a corresponding plurality of recesses 122, each filled with a suitable sealant 124 to thereby improve the integrity of the seal. Similarly, the materials from which the plug, the gland, and the sealant are made could vary from that described herein. Also, necessary variations will need to be made where different packaging systems are employed.
It should be understood in this specification that the terms “up”, “down”, or “above” and “below” are not intended to indicate that the filling operation must be conducted in a particular orientation. Those terms are simply intended to assist with the description of the preferred embodiments and indeed it is envisaged that the system could well be used to fill horizontally or vertically or at an inclined angle. These terms should therefore not be in any way limiting on the ambit of the invention.
It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.
The foregoing describes embodiments of the present invention and modifications, obvious to those skilled in the art can be made thereto, without departing from the scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| PP4374 | Jun 1998 | AU | national |
| PP8262 | Jan 1999 | AU | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/AU99/00514 | 6/25/1999 | WO | 00 | 4/9/2001 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO00/00390 | 1/6/2000 | WO | A |
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|---|---|---|
| 2135488 | Mar 1989 | AU |
| WO 8900952 | Feb 1999 | WO |
