Method and apparatus for inerting head space of a capped container
A process to reduce oxygen in the head space of containers includes introducing an inert gas into the container head space. This may be accomplished during a capping process. Multiple conduits may be used to introduce the inert gas. The one or more conduits may be angularly offset from either or both of a plane defined by the opening of the containers and a direction of movement of the containers at the time the inert gas is introduced. In certain embodiments, the openings of the one or more inert gas conduits may be remote from spaces defined by projections of the container openings.
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.
SUMMARY OF THE INVENTIONIn general, an invention having the desired features and advantages is achieved by injecting 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 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 apparatus having an opening remote from a space defined by a projection of the opening of the container.
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 at least one conduit coupled to the inert gas source. The at least one conduit has an exit opening for the inert gas to exit the at least one conduit. The apparatus further includes a capping device for disposing a cap onto the container to seal the container. The apparatus is operable to introduce an inert gas into the head space as the relationship between the cap and opening are changed from a first position to a second position. A distance between the cap and opening is smaller at the first position than at the second position. The exit opening of the at least one conduit is remote from a space defined by a projection of the opening of the container.
The present invention has 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 inerting process can be carried out between filling and capping the container without adding any time to the overall process. Additional features and advantages of the invention will become apparent in the following detailed description and in the drawings.
BRIEF DESCRIPTION OF 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.
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.
Claims
1. A method 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 cooperating to define a head space above the potable liquid, comprising the step of:
- 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;
- introducing an inert gas toward the opening when the cap and opening are at the second position; and
- sealing the cap on the container with the inert gas enclosed in the head space,
- wherein the inert gas is delivered from an apparatus having an opening remote from a space defined by a projection of the opening of the container.
2. The method of claim 1, wherein the cap is in contact with the container when the inert gas is introduced.
3. The method of claim 1, wherein the apparatus comprises at least one conduit.
4. The method of claim 1, wherein the apparatus comprises only one conduit.
5. The method of claim 1, wherein the apparatus comprises a plurality of conduits.
6. The method of claim 1, wherein the apparatus comprises at least one conduit having an axis angularly offset from a direction of movement of the container at the time the inert gas is introduced.
7. The method of claim 6, wherein the angular offset is in the range of from 30 to 50 degrees.
8. The method of claim 6, wherein the angular offset is in the range of from 40 to 45 degrees.
9. The method of claim 1, wherein a direction of flow of the inert gas from the apparatus is angularly offset from a direction of movement of the container at the time the inert gas is introduced.
10. The method of claim 1, wherein the apparatus comprises at least one conduit having an axis angularly offset from a plane defined by the opening of the container.
11. The method of claim 10, wherein the angular offset is in the range of from 15 to 40 degrees.
12. The method of claim 10, wherein the angular offset is in the range of from 25 to 35 degrees.
13. The method of claim 1, wherein the apparatus comprises at least one conduit having a bend formed therein, the bend connecting a first conduit portion with a second conduit portion.
14. The method of claim 13, wherein the first conduit portion defines a first axis and the second conduit portion defines a second axis, the second axis being coaxial with a direction of flow of the inert gas exiting the conduit.
15. The method of claim 14, wherein the first axis is substantially perpendicular to a plane defined by the opening of the container.
16. The method of claim 14, wherein an angle between the first and second axes is in the range of from 140 to 165 degrees.
17. The method of claim 14, wherein an angle between the first and second axes is in the range of from 145 to 155 degrees.
18. The method of claim 1, further comprising determining an exit area from which the inert gas exits the apparatus based at least in part on the size of the opening of the container.
19. The method of claim 1, further comprising introducing the inert gas at a flow pressure and velocity determined not to displace the potable liquid from the container.
20. The method of claim 19, wherein the flow pressure is in the range of from 10 to 30 psi.
21. The method of claim 19, wherein the flow pressure is in the range of from 12 to 18 psi.
22. The method of claim 19, wherein the flow pressure is about 15 psi.
23. The method of claim 19, wherein the velocity is in the range of from 6-9 cfm.
24. The method of claim 19, wherein the velocity is about 8 cfm.
25. The method of claim 1, wherein the apparatus comprises at least a first conduit and a second conduit, a direction of flow of inert gas from the first conduit defining a first angle with respect to a plane defined by the opening of the container, and a direction of flow of inert gas from the second conduit defining a second angle with respect to the plane.
26. The method of claim 25, wherein the first and second angles are substantially equal.
27. The method of claim 25, wherein the first and second angles are offset.
28. The method of claim 27, wherein the first angle is determined to direct the flow of inert gas from the first conduit more toward the cap than toward the opening of the container.
29. The method of claim 28, wherein the second angle is determined to direct the flow of inert gas from the second conduit more toward the opening of the container than the flow of inert gas from the first conduit.
30. The method of claim 27, wherein the second angle is determined to direct the flow of inert gas from the second conduit more toward the opening of the container than toward the cap.
31. The method of claim 1, further comprising processing a plurality of containers, each of the containers having an opening, and wherein an inert gas exit opening of the apparatus is remote from spaces defined by projections of each of the container openings during the processing step.
32. An apparatus for introducing an inert gas into a head space of a container, the container and cap cooperating to define the head space above a potable liquid in the container, the apparatus comprising:
- an inert gas source;
- a least one conduit coupled to the inert gas source, the at least one conduit having an exit opening for the inert gas to exit the at least one conduit; and
- a capping device for disposing a cap onto the container to seal the container,
- the apparatus operable to introduce an inert gas into the head space as the relationship between the cap and opening are changed from a first position to a second position, a distance between the cap and opening being smaller at the first position than at the second position,
- and wherein the exit opening of the at least one conduit is remote from a space defined by a projection of the opening of the container.
33. The apparatus of claim 32, wherein the at least one conduit comprises only one conduit.
34. The apparatus of claim 32, wherein the apparatus comprises a plurality of conduits.
35. The apparatus of claim 32, wherein the at least one conduit has an axis angularly offset from a direction of movement of the container at the time the inert gas is introduced.
36. The apparatus of claim 32, wherein a direction of flow of the inert gas from the at least one conduit is angularly offset from a direction of movement of the container at the time the inert gas is introduced.
37. The apparatus of claim 32, wherein the at least one conduit has an axis angularly offset from a plane defined by the opening of the container.
38. The apparatus of claim 32, wherein an exit opening of the at least one conduit has an area based at least in part on the size of the opening of the container.
39. The apparatus of claim 32, wherein the at least one conduit comprises a first conduit and a second conduit, a direction of flow of inert gas from the first conduit defining a first angle with respect to a plane defined by the opening of the container, and a direction of flow of inert gas from the second conduit defining a second angle with respect to the plane.
40. The apparatus of claim 39, wherein the first and second angles are substantially equal.
41. The apparatus of claim 39, wherein the first and second angles are offset.
42. The apparatus of claim 39, wherein the first angle is determined to direct the flow of inert gas from the first conduit more toward the cap than toward the opening of the container.
43. The apparatus of claim 39, wherein the second angle is determined to direct the flow of inert gas from the second conduit more toward the opening of the container than the flow of inert gas from the first conduit.
44. The apparatus of claim 39, wherein the second angle is determined to direct the flow of inert gas from the second conduit more toward the opening of the container than toward the cap.
Type: Application
Filed: Sep 26, 2006
Publication Date: Jan 25, 2007
Inventors: Kurt Ruppman (Allen, TX), Kraig Ruppman (Frisco, TX)
Application Number: 11/535,150
International Classification: B65B 31/02 (20060101); B65B 31/00 (20060101);