Smoke generating device

A smoke producing device for use in a barbecue or the like is disclosed comprising a smoke producing material, such as wood chips, enclosed in a noncombustible perforated container. The perforations are kept covered by a perforation cover until use so as to prevent leakage of the smoke producing materials from the container and to prevent the loss of moisture and volatile aromatic oils from the smoke producing material. This cover is preferably constructed of a combustible material so that when heated in a barbecue, it will ignite and burn off to expose the perforations, through which the smoke can then escape to flavor the food.

TECHNICAL FIELD 
The present invention relates to smoking foods, and more particularly to an 
improved device for generating food flavoring smoke in a barbecue or the 
like. 
BACKGROUND AND SUMMARY OF THE INVENTION 
With the advent of charcoal briquets, gas fired barbecues and stove top 
grills, the natural smoke flavoring imparted to foods by traditional 
grilling methods, such as over smoldering wood coals, has been lost. 
Consequently, it has become desirable to be able to provide a natural wood 
smoke flavoring to foods cooked by these methods. Several unsatisfactory 
techniques have been proposed. 
One prior art technique for imparting a smoke flavor to cooked meats and 
the like is to soak the food in a chemical flavoring agent. 
This approaches suffer from a number of drawbacks. First is the natural 
concern of soaking an edible foodstuff in an unknown chemical agent. The 
risks associated with these chemicals are not yet fully known. A second 
drawback is that these chemicals sometimes act to draw out the food's 
natural juices to the surface, from which location they can drip to the 
barbecue or be consumed by fire. The loss of these natural juices dries 
out the food and sometimes alters its normal taste. A final drawback of 
the chemical approach is the attendant sacrifice in smoke flavor. Most 
smoke flavoring chemicals are entirely artificial. The flavor they impart 
bears little resemblance to the true wood smoke flavor being imitated. 
Even those chemical flavoring agents that are actually derived from wood 
products perform poorly because many of the desirable flavors obtained 
from wood smoking are formed when the aromatic agents within the wood are 
combusted. The chemicals used to treat the food are not combusted, as they 
are usually absorbed into the food and not heated to ignition. 
Consequently, even with "natural" liquid smoking agents, the desired 
traditional smoke flavor is not obtained. 
An approach related to soaking the food in a chemical flavoring agent is to 
enclose the food in a casing formed from precipitate materials derived 
from these chemical agents. This approach also suffers from the 
above-recited drawbacks. Examples of this approach are shown in U.S. Pat. 
Nos. 4,446,167 and 4,442,868. 
Yet another approach to imparting a smoke flavoring to cooking foods is to 
provide a packet of smoke producing material, such as wood flour, in a 
Kraft paper wrapper suspended above the coals of the barbecue. When the 
Kraft paper is ignited by the hot coals, the wood flour spills onto the 
coals and ignites, thereby producing smoke. U.S. Pat. 4,190,667 to Robins 
shows such a system. 
Although an improvement over the chemical treatment methods, this Robins 
approach still suffers from several drawbacks. One is that the smoke is 
generated by the ignition of the wood flour. Such ignition consumes the 
entire material quickly and produces only a small amount of smoke. A 
second drawback is that the wood flour falls onto the coals all at once 
when the Kraft paper burns through. Accordingly, the smoke so generated is 
produced all at once and is not released continuously during cooking of 
the food. As a final drawback, the Kraft paper wrapper is moisture 
permeable, thereby allowing the wood flour material contained therein to 
dry out and lose much of its aromatic quality. 
Still another approach to generating wood-flavored smoke is to add wood 
chips to the coals of a barbecue. The chips can be soaked in water to slow 
their combustion. Despite such precautions, the chips nonetheless are 
consumed quickly and the smoke produced therefrom is consequently of short 
duration. Furthermore, this technique cannot be used with devices such as 
gas fired barbecues or stove top grills because such devices might be 
damaged in the process. 
A final prior art smoke producing system is shown in U.S. Pat. No. 
2,967,023 to Huckabee. Huckabee uses a perforated aluminum bag that 
contains a smoke producing material such as wood chips. In use, the bag is 
placed on the coals, thereby heating the wood chips and causing them to 
smolder. The wood chips are not permitted to ignite because the 
perforations are too small to admit air sufficient to support combustion. 
As the chips within the bag smolder, smoke is emitted through the 
perforations. 
Although an improvement over prior art methods, the Huckabee device still 
leaves substantial opportunities for improvement. 
In order to overcome the numerous drawbacks found in the prior art, an 
improved device for producing smoke in a barbecue or the like has been 
devised. 
It is one object of the present invention to provide a smoke generating 
device that limits exposure of the smoke generating material contained 
therein to the surrounding environment until the device is used. 
It is another object of the present invention to prevent the loss of 
moisture from smoke generating material in a smoke generating device until 
the device is used. 
It is still another object of the present invention to provide a smoke 
generating device in which smoke exhaust holes are automatically uncovered 
when the device is used in a barbecue or the like. 
It is yet another object of the present invention to provide smoke 
generating device in which exposure of the smoke generating material to 
the surrounding environment is prevented by a sealing material that can be 
removed before the device is used. 
These and other objects, features and advantages of the present invention 
will become more readily apparent from the following detailed description, 
which proceeds with reference to the accompanying drawings.

DETAILED DESCRIPTION 
With reference to FIGS. 1-6, a smoke generating device 10 according to the 
present invention comprises an incombustible container 12 formed, for 
example, of aluminum foil, containing a smoke producing material 14. Smoke 
producing material 14 can be any of a number of different agents, such as 
wood chips, crushed almond shells, etc. This material is shown largely in 
cross hatch form in FIGS. 2, 4 and 6 for clarity of presentation. 
In the preferred embodiment, device 10 is cylindrical in form, being rolled 
from aluminum foil and having its ends closed. The cylinder illustrated is 
one and one-eighth inch in diameter by two and a quarter inches long. It 
has been found that crimping the ends of the cylinder with a crimp 15 is 
an effective way to provide a substantially air-tight seal. The 
effectiveness of this seal can be enhanced if the crimps are twisted as 
they are being formed, as illustrated in FIGS. 1, 3 and 5. The illustrated 
device contains approximately one-half ounce of smoke producing material. 
Container 12 includes at least one smoke exhaust hole 16 through which 
smoke can escape the container when smoke producing material 14 is heated 
to smoldering in a barbecue or the like. In the preferred embodiment, 
container 12 includes a plurality of holes 16 spaced in linear array along 
the container. In use, container 12 is positioned in the barbecue with 
these perforations oriented vertically so that the smoke will escape 
therethrough as it rises from the smoldering smoke producing material 
contained therein. 
The placement of holes 16 on container 12 is important to proper operation. 
If the holes are not oriented vertically when the device is used, the 
rising smoke may not escape the package, thereby limiting its 
effectiveness. The rate of smoke emitted from the package is also 
dependent on the pattern of holes. If the holes are formed both at the top 
and near the bottom of the package, as the package is oriented for use in 
a barbecue, air is able to flow in through the bottom holes, up through 
the smoke producing material, and out through the top holes. The 
smoldering is thus accelerated. It is generally more desirable to provide 
holes only in the top of the package so that the rate of air flow through 
the container, and consequently the rate of smoldering, is limited. 
The size of the holes is also crucial. If the holes are too large, 
sufficient air will enter to support combustion of the smoke producing 
materials, with a consequent decrease in the quantity and quality of smoke 
produced. Furthermore, flaming fat which falls from cooking meat may fall 
onto large holes and be allowed to enter the cylinder therethrough and 
ignite its contents. If, on the other hand, the holes are too small, not 
enough smoke will be released to flavor the food. A suitable compromise 
between these countervailing considerations is to use approximately 
eighteen holes one-eighth inch in diameter arrayed on the top surface of 
the device. 
In order to prevent leakage of smoke producing material 14 from container 
12 and to prevent the loss of moisture and volatile aromatic oils from the 
smoke producing material, a cover 18 (FIGS. 3-6) is provided in the 
present invention to cover perforations 16 until smoke generating device 
10 is placed into service. 
According to one feature of the present invention, cover 18 can be formed 
of a combustible material so that it ignites and burns off to expose 
perforations 16 when the device is heated in a barbecue or the like. With 
reference to FIGS. 3 and 4, cover 18 can be formed to totally encircle 
container 12. Such covering can be effected by wrapping a material such as 
paper around the container or by forming a layer of wax on the device, 
such as by spraying or dipping. Alternatively, as shown in FIGS. 5 and 6, 
cover 18 can be formed of a narrow strip of combustible or meltable 
material designed to cover only perforations 16 and to leave the remainder 
of container 12 uncovered. In either event, cover 18 combusts or melts 
away from or the like. 
According to another feature of the present invention, cover 18 can be 
removably fastened to container 12 so that it can be manually removed 
before the device is used. The cover 18 shown in FIGS. 3 and 4 can, for 
example, be formed with a paper wrapper that can be peeled off to expose 
the perforations on the device. Alternatively, as shown in FIGS. 5 and 6, 
cover 18 can comprise a narrow strip of material designed to cover only 
the perforations. In either event, one portion of cover 18, such as end 20 
in FIG. 5, can be left free and not bonded to container 12 so as to 
provide a tab which can be grasped to remove the cover from the container. 
It is of course desirable, when using a construction in which the cover is 
adhesively bonded to the container, that any bonding residue left behind 
after the cover is removed not produce an objectionable flavor when it is 
consumed in the fire. It has been found that common wax is such a suitable 
bonding agent that has the added benefit of being moisture impermeable 
while intact. Wax can be used, for example, both to bond an onionskin-like 
paper or cigarette rolling paper around the cylinder and to make such 
paper moisture impermeable. 
Similarly, if a combustible seal is provided, the material that combusts to 
expose the holes must also be selected so that it will not impart an 
objectionable flavor to the food. Cigarette paper and wax are suitable 
alternatives. 
In the illustrated aluminum cylinder construction, an edge 22 of the 
aluminum foil is left on the outer surface of the device. Some exchange of 
moisture and aromatic oils may take place under this edge. This 
possibility can be minimized by encircling the cylinder with more than 360 
degrees of foil (for example, the cylinders in FIGS. 2, 4 and 6 are 
illustrated as including 540 degrees of foil). To further minimize the 
effect of open edge 22, cover 18 can be positioned so as to cover it. In 
FIG. 3, cover 18 encloses the entire cylinder, including the edge 22. In 
FIG. 5, cover 18 can be sized so that it also covers opening 22. 
Perforations 16 can be formed during manufacturing so that they are 
adjacent edge 22 in order to facilitate closure of the associated air 
passageway with cover 18. 
Alternative forms for the present invention are shown in FIGS. 7 and 8. 
FIG. 7 is a construction akinato many candy bar wrappers in which the 
container wraps around the smoke producing material and has its ends 
crimped flat. FIG. 8 shows an aluminum cup 26 filled with a smoke 
generating material and covered with a perforated piece of foil 28 that is 
crimped to the lip of the cup. A combustible perforation cover 18 covers 
the perforations in foil 28. 
Having described and illustrated the principles of my invention in a 
preferred embodiment and a few variations thereof, it should be apparent 
that the invention can be modified in arrangement and detail without 
departing from such principles. For example, container 12 can assume any 
of a number of shapes. Similarly, a number of variations can be made in 
the type of coverings applied to holes 16. Accordinqly, I claim as yy 
invention all modifications coming within the scope and spirit of the 
following claims and equivalents thereof.