This invention relates to bottling of potable fluids subject to microbial attack. In particular, the invention relates to a method and apparatus for extending the shelf life of such potable fluids stored in non-pressurized containers with snap-on caps by flushing the container with an inert gas. Also, certain aspects of the invention may involve at least partially displacing the oxygen in the cap and in the container head space with an inert gas.
It has long been recognized that removing gaseous oxygen from sealed containers containing potable liquids can extend their shelf lives by reducing the rate of spoiling from microbial attack. Vacuum packaging and the use of bags have been used to eliminate gas altogether from packaging, but inerting, or the filling of the unfilled container space with an inert gas, is also widely used.
In a popular method of inerting, a small dose of liquid nitrogen is injected into a filled container just prior to capping. The nitrogen vaporizes, which displaces oxygen from the container's head space during capping. Some liquid nitrogen remains in the container after capping and vaporizes in the sealed container, which pressurizes the container. However, this method is not useful for non-pressurized containers such as milk and juice bottles. The snap-on caps for these containers are not designed to withstand the pressures developed by the vaporized nitrogen, and the increased pressure created by the vaporized nitrogen breaks the seal between the cap and bottle, allowing air to be sucked back into the container during handling and shipping, renewing microbial attack. As a result, shelf life of non-pressurized capped containers is not significantly extended using this method.
Methods have been developed for inerting the head space in non-pressurized containers such as the classic gable-top paper container. U.S. Pat. No. 6,634,157 issued to Anderson et al. on Oct. 21, 2003 discloses an apparatus and method for filling these containers. It makes used of a special nozzle inserted into the container after filling with product and prior to sealing the container. The inerting step must be carried out as a separate step between filling and sealing the container, and therefore adds more time to the overall packaging cycle, which reduces throughput. Also, the apparatus for positioning, operating and removing the nozzle is complex and relatively expensive.
In general, certain aspects of the invention involve maintaining low oxygen levels within the sealed container. One may inject an inert gas such as nitrogen simultaneously into the head space of a filled container and the cap used to seal the container during the capping procedure.
In one example embodiment, a method is provided for extending shelf life of a potable liquid in a container sealed by a cap enclosing an opening of the container. The container and cap cooperate to define a head space above the potable liquid. One step of the method is changing the relationship between the cap and opening from a first position to a second position, wherein a distance between the cap and opening is smaller at the first position than at the second position. Another step is introducing an inert gas toward the at least one of the cap and the opening when the cap and opening are at the second position. Another step is sealing the cap on the container with the inert gas enclosed in the head space. The inert gas is delivered from an attachment coupled to a chute. The chute delivers the cap toward the container. The attachment has a body portion pressurized with the inert gas.
In another example embodiment, an apparatus is provided for introducing an inert gas into a head space of a container. The container and cap cooperate to define the head space above a potable liquid in the container. The apparatus includes an inert gas source and a cap chute for transporting a cap from a cap source to the container. The apparatus further includes an inert gas attachment coupled to the inert gas source and to the cap chute. The inert gas attachment includes a coupling section for coupling to the inert gas source and a body portion having a space defined therein. The body portion is coupled to the cap chute. Inert gas from the gas source is directable into the body portion to pressurize the space therein with inert gas. The inert gas is transferable from the body portion toward at least one of the cap and container as the cap and container are brought into contact with each other to form the head space.
Certain aspects of the present invention may have advantages over other methods and apparatus for inerting. Less equipment and space is needed than for apparatus using an inert gas filled environment. The apparatus for carrying out the method of the invention can easily be adapted to existing capping equipment. The inerting process provides improved reduction of oxygen within the container. The head-space inerting process can be carried out between filling and capping the container without adding any time to the overall process. One or more, or none, of these advantages may be provided by any particular embodiment of the invention. Additional features and advantages of the invention will become apparent in the following detailed description and in the drawings.
A need remains for an effective method and apparatus for inerting a beverage container. Such a method preferably should work with established capping apparatuses and require a minimum of space for the inerting apparatus. In addition, a method and apparatus that can perform the inerting without adding additional time to the overall filling/sealing procedure would be considered advantageous.
A chute 13 is used to transport caps 15 to the bottles 17. Each cap 15 has a top member 19 and a skirt 21 depending from the top member 19 and defining a partially enclosed skirt volume 23 with the top member 19. At the end of the chute 13, a pivotable arm (not shown) holds the next cap 15 to be used in the proper position for being put onto a bottle 17. As the bottle 17 moves along the conveyer track 25 past the cap 15, the skirt 21 engages the bottle 17. The moving bottle biases the cap 15 so that it is released by the pivotable arm and passes under a plate 29 that biases the cap downward, sealing it onto the bottle 17.
The apparatus 11 of the invention comprises a pair of injectors 31, 33 made from nominal half-inch copper tubing mounted on a header block 35 which in turn is attached by an adjustable linkage 37 to the chute 13. Flexible tubing 39 connects the header block 35 to a supply of pressurized nitrogen, preferably through a control loop having a control valve and flow controller (not shown), although other schemes can be used such as manually operated throttling valve and a pressure gauge located between the valve and the header block 35. An alternative embodiment is envisioned but not shown, wherein the header block 35 is absent and the injectors 31 and 33 are individually supplied by flexible tubing or other suitable conduit to the pressurized inert gas supply.
Because the injectors must be located close to the chute 13, the injectors 31 and 33 are separated by a gap 41 to allow tags 43 extending from the caps 15 to pass between the injectors unobstructed. While simple copper tubing is shown, other types of injectors known in the art can also be used, including other cross sectional types such as dispersion fans. Jets and devices that produce a narrow gas stream are not prohibited but are not preferred since a narrow, high velocity gas stream is more likely to produce splashing or otherwise disturb the surface of the container contents. Regardless of the injector shape, one feature of this illustrated example is the proper orientation of the injectors 31, 33 so that the inert gas stream is directed at or just below the point where the cap skirt 21 initially engages the bottle, in order to ensure that both the bottle head space and the cap skirt volume are properly flushed by the inert gas. The adjustable linkage 37 allows the user to experiment with orientation for best results with various equipment models, when the apparatus 11 is retrofit on existing capping equipment. However, the adjustable linkage can be replaced with a fixed mounting bracket or other unadjustable hardware for a particular piece or model of equipment or when manufactured as an integral part of the capping equipment.
The flow of nitrogen is set from about fifty to about two hundred standard cubic feet an hour (SCFH) to ensure the desired reduction of the oxygen level in the head space of a one-gallon milk container. The injectors operate continuously, so that there is some waste of the inert gas in the time interval between containers. The injectors are angled at about fifteen to forty degrees from horizontal, and preferably from about twenty to twenty-five degrees from vertical, and oriented so that a significant part of the flow stream flushes the skirt volume 23. This is necessary because trials have shown that the gas trapped in the skirt volume 23 tends to displace gas from the head space during capping rather than being pushed out into the surrounding environment, so that the gas composition in the cap has a significant impact on the final gas composition in the sealed head space.
The flow of inert gas may be selected so that the oxygen level in the sealed container is less than about fourteen percent by volume, and preferably less than about twelve percent by volume. By contrast, the prior art does not mention any allowable upper limit for oxygen content, and generally implies that proper inerting requires removal of essentially all oxygen from the head space. The inventor has discovered that practical extension of shelf life occurs even when oxygen levels in the head space are as high as about fourteen percent, with shelf life increasing with decreasing oxygen level. As the oxygen level is reduced below six percent by volume, there is a diminishing return to how much shelf life is extended with reduced oxygen level. The discovery that, in certain circumstances, the head space need not be flushed completely free of oxygen makes these example embodiments practical. For example, in certain situations, it is not necessary to insert an inert gas injector into the head space in order to ensure complete flushing of the head space, so the apparatus can be achieved without interfering with the conventional operation of the capping equipment, so there is no throughput penalty. Since complete removal of oxygen is not required, there is no need to create an oxygen-free environment around the container during capping, which eliminates the need for expensive, complicated and bulky apparatus for creating an artificial contained atmosphere around the bottles.
The invention has several advantages over the prior art. The method can be carried out simultaneously and independently of the conventional capping process, so throughput is essentially unchanged. The apparatus is simple and inexpensive to install, and requires relatively little space, especially in comparison to methods and apparatus that create an enclosed low-oxygen atmosphere surrounding the containers during capping. Existing capping equipment can be easily retrofitted to practice the method of the invention.
In still another embodiment, the inert gas may be introduced into the head space via one or more conduits as illustrated in
As illustrated in
Each of the conduits 501 and 502 is shown with a bend. However, a bend is not required and the conduits may have any suitable configuration. The configuration of the conduits may depend, for example, on other processing equipment. Also, one conduit may be configured differently than the other conduit.
As illustrated in
In the illustrated example, the non-vertical portion has a vertical angular offset may be defined by either angle C or angle F. Preferably, the offset defined by angle F is in the range of from 15 to 40 degrees. More preferably, the range is from 25 to 35 degrees. Thus, defined by angle C, the offset is preferably from 140 to 165 degrees and more preferably from 145 to 155 degrees.
In another embodiment, as illustrated in
In one configuration, cap chute 13 is closed along its length. That is, the chute 13 does not have a gap as in certain of the embodiments previously described. In this case, body portion 58 is preferably closed at a distal end 60 and open at a gas exit end 62. In one embodiment, a side of attachment 52 adjacent chute 13 is also open for a part of body portion 58 near distal end 62.
In operation, the gas supply directs inert gas to the first end 55 of coupling section 54. The gas travels through coupling section 54 to the second end 56 where the gas enters body portion 58. As shown in
Inert gas within body portion 58 is trapped with the exception of the opening portions at gas exit end 62. Thus, pressurized inert gas flows through these open portions. The open portion at the gas exit end 62 allows inert gas to flow toward the head space of bottle 17 as the cap 15 is being applied. The open portion on the side adjacent chute 13 near gas exit end 62 allows inert gas to flow toward the interior space within cap 15 as it is being affixed to bottle 17. Thus, inert gas may be simultaneously applied to the cap and the bottle opening at the time the cap is being applied to the bottle. This inert gas displaces oxygen from these spaces, thereby inerting the head space of the capped bottle.
In other configurations, the cap chute 13 may have one or more openings (not expressly shown) along its length. The chute attachment 52 may likewise have one or more openings along the side adjoining chute 13. Thus, inert gas within body portion 58 may be transferred to the interior space of chute 13. In one example, body portion 58 has an opening facing chute 13 near the distal end 60. Chute 13 has a corresponding opening facing attachment 52. Inert gas is transferred from body portion 58 to the interior of chute 13. The inert gas may travel downward in the same direction as caps 15. At least some of the inert gas is trapped in the interior space of caps 15. When a cap 15 is attached to a bottle 17, the inert gas in the cap 15 is likewise trapped in the head space of the capped bottle 17.
In another example of a configuration in which the chute and attachment have one or more openings, the opening(s) on the chute 13 are limited to that portion of chute 13 which is coupled to attachment 52. In this manner, no inert gas may escape upward and through an opening in chute 13 into the atmosphere.
In another example of a configuration in which the chute and attachment have one or more openings, multiple openings are provided along the attachment, and the chute has a longitudinal gap or slot facing the attachment. Thus, the chute as previously described in connection with
The invention has been shown in several embodiments. It should be apparent to those skilled in the art that the invention is not limited to these embodiments, but is capable of being varied and modified without departing from the scope of the invention.
This application is a continuation-in-part application claiming the benefit of pending U.S. patent application Ser. No. 11/029,326 filed Jan. 5, 2005, entitled Method and Apparatus for Inerting Head Space of a Capped Container and U.S. patent application Ser. No. 11/535,150 filed Sep. 26, 2006, entitled Method and Apparatus for Inerting Head Space of a Capped Container.
Number | Date | Country | |
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Parent | 11029326 | Jan 2005 | US |
Child | 11555631 | Nov 2006 | US |
Parent | 11535150 | Sep 2006 | US |
Child | 11555631 | Nov 2006 | US |