This invention relates to a canned product which generates a gaseous pressure buildup, and to an improved arrangement for venting such gases.
Historically, ground roast coffee packaged in a can has been vacuum packed. Recently, it has been found desirable to freshly package roast ground coffee in cans or other rigid or semi-rigid gas impervious packages under atmospheric pressure as contrasted to the prior vacuum packaged cans. Additionally, it has also been found desirable to close off the top of the can with a flexible peel-off easy opening seal or lid, whether the coffee was packed under a vacuum or atmospheric pressure. Examples of such peel-off easy opening lids are shown in the Bolton et al U.S. Pat. No. 5,688,544.
Packaged ground roast coffee gives off carbon dioxide which, in a sealed confined space will generate a pressure buildup within the container. In the case of vacuum packed ground roast coffee, this generation of carbon dioxide causes no problem because the pressure buildup simply tended to reduce the negative pressure within the sealed container. However, if the product is freshly packaged initially at atmospheric pressure without extensive degassing, then generated carbon dioxide will cause a pressure buildup in the can above atmospheric pressure. In atmospheric pressure packed ground roasted coffee cans now on the market, this pressure buildup caused by the generated carbon dioxide is dealt with by simply placing a vent valve in the top of the can. If the can is of a type having a flexible peel-off seal, the vent valve will be built directly into the flexible peel-off lid.
It is also highly desirable, if not a commercial necessity, to include with any coffee can a plastic overcap which is intended primarily to protect the coffee product within the package after the main airtight seal has been opened.
A problem has developed, however, in the case of a ground roast coffee can having a vented peel-off lid and a plastic overcap. It has been found that as the gas pressure builds up within the can it tends to dome the flexible lid upwardly and eventually against the overcap. This creates several problems. First, the constant extension of the flexible lid in its domed condition deforms the flexible lid, causing a wrinkled appearance which is unacceptable to the consumer. Additionally, the materials used to seal the vent valve to the lid, including silicon-based oils, would tend to be expelled from the valve opening and onto the surface of the overcap. This causes a visual blemish which is also unacceptable to the consumer. Additionally, if the valve is sufficiently blocked, the gas within the can can cause the can itself to bulge outwardly, which again is unacceptable to the consumer.
While a primary problem has been blockage of the vent valve in the flexible easy-off lid, an additional problem arises in that gases which do escape through the lid may not be able to escape from the space between the lid and the overcap. It is true that the overcap is simply snapped over the chime of the can in a non-airtight manner. However, the surfaces of the overcap which engage the chime of the can, generally along the top and outer periphery of the chime, while not forming a hermetic seal, clearly form a closure which resists escape of any generated gases which might exit from the vent valve into the space between the lid of the can and the overcap.
Thus, a need exists for an improved arrangement for venting gases created within a can wherein the product is packed under atmospheric pressure and is of the type which generates gases sufficiently to cause a pressure buildup, especially when such a can is used in combination with an overcap.
It is a purpose of the present invention to provide a new and improved arrangement for venting gases which build up in a package of the type wherein the product is packaged under atmospheric pressure in a can having a flexible lid with a vent valve and an overcap. More specifically, it is the purpose of the present invention to provide such an improvement for the fresh packaging of ground roast coffee in a can under atmospheric pressure. The term “can” is intended to encompass various types of containers and packages, including the usual cylindrical metallic can as well as rectangular cans, thin metallic cans of any shape and non-metallic cans.
In accordance with the present invention, an arrangement is provided for preventing the vent valve to be closed off by contact with the overcap. This arrangement comprises a spacing structure preferably formed in or on the bottom of the overcap, which prevents the vent valve in the lid from being closed by contact with the plastic overcap. In one preferred embodiment, this is achieved by providing bosses on the lower, internal surface of the overcap which will engage the flexible lid as it moves upwardly so as to limit such upward movement to such a height that the vent valve remains unblocked and the vented gases are permitted to flow therethrough. Preferably the bosses engage the vent valve in such a way as to block its upward movement while not occluding the vent valve opening. The bosses can take many different shapes such as thin ribs, rectangular cross sections and the like.
In another preferred embodiment, the spacing structure may take the form of a pocket formed in the bottom of the overcap and of such a depth that it allows the flexible lid to reach its maximum height caused by the gas buildup without the flexible lid or the vent valve engaging the overcap.
Additionally, the present invention may include a permanently open passageway at the interface between the overcap and the chime of the coffee can which will allow the escape of any built-up gases which have passed through the vent valve into the space between the flexible lid and the overcap.
In a preferred embodiment, this permanently open passageway between the overcap and the chime of the can can be provided by providing some raised bosses on the inside surface of the plastic overcap precisely where it engages the chime of the can. A series of such bosses, arranged side-by-side, would thereby provide a permanently open passageway between the bosses.
Thus, it is an object of the present invention to provide a new and improved arrangement for venting built-up gases in a can containing a product which generates gases and which can includes a flexible lid and an overcap.
It is another object of the present invention to provide a new and improved arrangement for venting gases from a can of the type described which includes a structure for preventing blockage of a vent valve in the flexible lid.
It is still another object of the present invention to provide an improved venting arrangement in a package of the type described which includes a structure for forming a permanently open passageway between the interface of the overcap and the chime of the coffee can.
These and other objects of the present invention will become apparent from the detailed description of the preferred embodiments.
Preferred embodiments of the present invention are illustrated in the accompanying drawings, wherein:
Referring now to the drawings, like elements are represented by like numerals throughout the several views.
A conventional can includes a chime 13 with inner edge 13a and a plastic overcap 20. The overcap engages the chime at contact lines 21 and 22. While these contact lines are not intended to provide a hermetic seal, they do to some extent restrict the flow of gas. The primary purpose of the overcap is to provide some protection for the product after the lid 12 has been removed. The overcap 20 also includes a lower part 23 which hangs below the chime and is not in contact with it.
The can 10 may be of any suitable material such as metal, plastic, composite materials, cardboard or other suitable materials. Between the time that a can such as that shown in
The vent valve is a commercial product made by Plitek, LLC. Referring to
The valve 16 is shown in greater detail in
Solutions to the problem described above are illustrated in
Referring to
The rib bosses 31–33 are all identical, and one of them is shown in detail in
In the package of
As noted above, the contact lines 21 and 22 between the chime of the can and the interior of the overcap 30, 40, 45, while not forming a hermetic seal, do offer some resistance to the flow of gases. Referring to
Although the invention has been described in considerable detail, it will be apparent that the invention is capable of numerous modifications and variations, apparent to those skilled in the art, without departing from the spirit and scope of the invention.
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20040096552 A1 | May 2004 | US |