Briquet packing density
Modified charcoal briquets having a pillow silhouette when viewed from at least one side and configured to have less volume than similar unmodified pillow shaped briquets having the same dimensions are described. A random packing density for the modified briquets is between about 0.70 times and 0.92 times a random packing density for the unmodified pillow shape briquets. The random packing density for the modified briquets is between about 35% and 46%.
This application is a continuation-in-part of pending U.S. application Ser. No. 29/208,910 filed Jul. 7, 2004, which is incorporated herein.
FIELD OF THE INVENTIONThis invention relates to the field of charcoal briquets and other solid fuel compositions.
BACKGROUND OF THE INVENTIONThere is great consumer interest in using charcoal for outdoor cooking in which meals can be prepared and served quickly for individual or large group consumption. Consumers desire cooking and grilling with charcoal briquets that are easily stackable to form the traditional starter pile, easily ignitable, maintain a uniform and efficient combustion that ignites the individual briquets in the starter pile, and have a sufficiently long burn period. Similarly, consumers desire to handle dirty charcoal as little as possible when forming traditional starter piles and the like.
Charcoal briquettes are often configured in a generally pillow-shape. This configuration provides for both reasonable ease of manufacturing by the supplier, and handling by the consumer. Pillow-shaped briquets are typically used for cooking on a grill or the like by pouring a multiplicity of briquets from a bag onto a grill to form a mounded or conical configuration or stack, adding lighter fluid, followed by igniting the mound of briquets with an ignition source.
An “ignition phase” follows as burning proceeds from the surface of the briquet. A gray ash is formed on a significant portion of each briquet until a majority of the exposed surfaces have ignited, and burning has progressed inwardly toward the intended area of the briquet. Thus, completion of the ignition phase is identified by the formation of visible ash on the briquet.
At this point, the briquets are spread out under a grill or the like, and they continue to burn with intense heat suitable for cooking and grilling throughout a “bum phase”. For maximum performance of the briquets, it is desirable that the ignition phase be limited in time so that the briquets may be used for cooking or grilling without undue delay, such that the duration of the burn phase is optimized and extended to provide adequate cooking or grilling time as desired by the consumer. After the briquets are burned thoroughly, ash remains.
There has been some previous work in the ornamental and geometrical configuration of charcoal briquets. For example, U.S. Des. 389,453 to Mitchell et al. describes a charcoal briquet having a groove generally in the shape of the letter “K”, and U.S. Pat. No. 4,496,366 to Peters describes charcoal having a briquet, or other geometric configuration, purportedly to achieve desired lighting and burn characteristics. In another example, U.S. Pat. No. 6,074,446 to Fujino describes charcoal having a plurality of air passing portions or grooves in its body purportedly to supply combustion air inside the charcoal body while burning.
However, previously known ornamental and geometrically configured charcoal briquets fail to address enhancing the surface of pillow-shaped briquets to improve packing density, and the random, non-mating stacking ability properties of the briquets, as well as to improve ignition and burn phase characteristics. Particularly charcoal briquets used for home grilling and cooking, wherein the consumer desires charcoal briquets that require less handling, and that can be readily ignited to provide maximum heat initially, followed by an improved burn phase.
SUMMARY OF THE INVENTIONIn accordance with the present invention, an improved modified charcoal briquet having a pillow silhouette when viewed from at least one side and configured to have less volume than a similar unmodified pillow briquets having the same dimensions.
The modified pillow shaped charcoal briquets of the present invention have a random packing density between about 0.70 times and 0.92 times a random packing density for the unmodified pillow briquets. Preferably, the random packing density for the modified briquet is between about 35% and 46%.
Modified pillow shaped charcoal briquets of the present invention having these improved random packing density characteristics have enhanced ignition and burn phase-properties, when compared to unmodified briquets having a pillow silhouette when viewed from at least one side.
These and other objects and advantages of the present invention will become apparent from the following description of the preferred embodiments of the invention, taken together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGSThe invention will be described in greater detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention, and wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The examples set out herein illustrate preferred embodiments of the invention, in one form, and such examples are not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTIONThe embodiments are illustrated in the context of charcoal briquets for consumer use. The skilled artisan will readily appreciate, however, that the materials and methods disclosed herein have application in a number of other contexts where solid fuel is used, particularly where low weight and high performance are important.
The shape of the pillow briquet is well known. Various views of a generalized pillow shape 100 as can be used for a briquet are shown in
where 0<n<1. As n approaches 0, corners 115 of the periphery 117 become more close to orthogonal. As n approaches 1, the corners 115 of the periphery 117 become more rounded. The periphery 117 becomes an ellipse when n=1. Any periphery described by Equation (1) can be suitable for a pillow briquet. The periphery 117 can also be characterized by lengths S1 and S2 of two sides. In
A silhouette is an outline of a solid object as cast by its shadow.
where 0<n<1. As n approaches 0, corners 215 of the periphery 217 become closer to orthogonal. As n approaches 1, the corners 215 of the periphery 217 become more rounded. The periphery becomes a circle when n=1. Any periphery described by Equation (2) can be suitable for a pillow briquet. The periphery 217 can also be characterized by the lengths S1 and S2 of the two sides. In
Packing density is defined as the fraction of a volume filled by a given collection of solids. The maximum packing density of spheres is 74.0%, which is achieved in cubic or hexagonal close packing arrangements. Spheres arranged randomly, for example, tossed into a container and then shaken, have a random packing density of only about 64%, which is significantly smaller than their maximum, ordered, packing density.
Packing densities can also be found for non-spherically shaped solids. In 2004, Chaikin showed that a random packing of about 125 pounds of M&M's® chocolate candies (oblate spheroids) has a random packing density of about 68%, or 4% greater than for spheres (Princeton University Press Release, Feb. 12, 2004).
The packing density of pillow-shaped briquets has been found to be about 50%. The packing density, of course, depends on the exact shape of the briquets. Pillow-shaped briquets are made by several manufacturers; dimensions S1, S2, h1, h2, as discussed above in
It has been found that by making small modifications to the form of pillow-shaped briquets, while still retaining the overall pillow shape and dimensions, the packing density of the briquets is reduced and several advantages are realized.
In Boolean geometry, multiple solid objects can be combined using Boolean geometric operations. Common operations include “union” (addition) and “difference” (subtraction) operations. Union operations combine two or more shapes. Difference operations can be used to cut one shape out of another.
Examples of Boolean difference operations are shown in
In
An example of a Boolean union operation is shown in
Small modifications to the form of pillow-shaped briquets can be made using Boolean geometric operations, while still retaining the overall pillow shape and dimensions. In some embodiments, the packing density of the modified briquets is less than the packing density of the briquets before modification (the unmodified briquets).
In the example in
The briquet 500 shown in
The briquet 600 shown in
In the example in
During the Boolean operation, only a portion of the disc or oblate spheroid 870 penetrates the pillow briquet 800. The maximum depth of intersection between the disc 870 and the briquet 800 can vary. The size of the portion of the oblate spheroid 870 can vary.
In the example in
In one embodiment, a charcoal briquet 900 is pillow shaped with an elliptical periphery when viewed from the top, as shown in the plan view in
In the example in
The foregoing embodiments are meant to serve as examples of possible briquet shapes that can result from performing Boolean operations on pillow briquets. Embodiments of the invention are not limited to these examples alone.
In some embodiments, the packing density of the briquets modified by Boolean operations is less than the packing density of the unmodified briquets. In some arrangements, the packing density for modified pillow briquets is between about 0.70 and 0.92 times the packing density for unmodified pillow briquets having about the same dimensions. In other arrangements, the packing density for modified pillow briquets is between about 0.80 and 0.88 times the packing density for unmodified pillow briquets having about the same dimensions. As discussed above, the packing density for unmodified briquets is about 50%. In some arrangements, the packing density for modified pillow briquets is between about 35% and 46%. In other arrangements, the packing density for modified pillow briquets is between about 40% and 44%.
The briquets as described in the embodiments herein and their reduced packing density have several advantages including weight advantages, ease of use, environmental and manufacturing advantages over ordinary pillow shaped briquets.
Reduced packing density results in several consumer advantages. Generally consumers decide how much charcoal to use for a particular cooking task based on volume, not weight. Consumers do not weigh briquets to determine the amount to use. Instead, they pour out an amount of briquets to make a pile of a certain size or to fill a chimney to a certain level. They judge the amount to use based on a randomly packed volume. It takes approximately the same number of modified briquets as unmodified briquets to fill the same randomly packed volume. Consumers consider the size of the grill and whether the amount of food they are cooking will cover the grill surface completely or only partially. Consumers want to have a sufficient number of burning briquets so that when they spread out, the briquets will provide an amount of cooking area sufficient for the task. The same number of briquets, either modified or unmodified, are sufficient for the task in most cases.
A bag of modified briquets that has about the same volume as a bag of unmodified briquets contains about the same number of briquets but weighs less. It is easier for a consumer to lift and carry a bag of modified briquets than a bag of unmodified briquets. It is easier to lift the bag and pour the briquets out into the grill. Yet, a consumer can use either bag of briquets to perform about the same number of cooking tasks.
Modified pillow briquets have environmental advantages. Typically when consumers finish a cooking task, there is still a lot of burn time left in the briquets. After cooking is finished, briquets continue to burn until the charcoal has all turned to ash. In many cases, the cooking time is very small compared to the total burning time of the briquets. As discussed above, consumers tend to determine the amount of charcoal briquets to use for a cooking task based on the randomly packed volume, not on the weight of the charcoal. For a given randomly packed volume of briquets, that is, a given number of briquets, the total burn time is less for modified briquets than for unmodified briquets because the total amount of charcoal is less. Cooking time constitutes a larger portion of the total burn time for modified briquets than for unmodified briquets. A larger portion of the total burn time is used in cooking for the modified briquets than for the unmodified briquets. Thus the burn time is used more efficiently for the modified briquets than for the unmodified briquets. For the same cooking task, less total charcoal weight is burned for the modified briquets than for the unmodified briquets. Less charcoal burned means a smaller amount of bum byproducts released into the air and less residual ash to remove.
The modified briquet can light more quickly and have a shorter ignition phase than the unmodified briquet. This can result in needing less lighter fluid to light the briquets and therefore a smaller amount of lighter fluid byproducts released into the air.
Modified briquets have manufacturing advantages. Less raw material is used to make the same number of modified briquets as compared to unmodified briquets. A modified briquet contains less actual material weight than an unmodified briquet so there can be less wear per briquet on the press rolls used to form the briquets. Less material per modified briquet can also mean that the raw briquets take less time to dry. As drying is often the limiting step in briquet manufacturing throughput, quicker drying can mean faster throughput in the manufacturing process. The advantages in faster throughput are many. This can result in greater output per factory, thus yielding a better return on large capital investment. This can result in greater overall efficiencies in labor and associated costs.
In many cases, the cost of transportation can be directly related to the weight transported. There are transportation cost advantages with modified briquets. These advantages start with transportation of raw materials. Less raw material is used to make modified briquets than to make unmodified briquets. The transportation costs associated with a given amount of raw material will be spread over production of more modified briquets than unmodified briquets. The cost savings continues with transportation of finished briquets. It takes about the same number of bags of modified briquets as unmodified briquets to fill a truck to its maximum volume. But a truck full of modified briquets weighs less than a truck full of unmodified briquets. Less weight means the truck uses less fuel per unit distance to transport the modified briquets than to transport the unmodified briquets. In many cases, trucks loaded with unmodified briquets reach their maximum weight limit before they reach their volume limit, so partially empty trucks are used to transport unmodified briquets. When modified briquets are loaded, more bags of briquets can be loaded before the truck reaches its maximum weight limit. This reduces the cost of transportation per bag by requiring fewer trucks overall to transport the same number of bags of briquets.
EXAMPLE An unmodified pillow briquet 200 having a shape approximately as shown in
Random packing mass density measurements were made by pouring as many briquets as could fit into a container having a known volume and weight. The weight of the container filled with briquets was measured for the unmodified pillow briquets and for the modified pillow briquets. The random packing mass density was found by dividing the weight of the briquets (total weight minus the weight of the container) by the volume of the container. The random packing mass densities are shown in Table I. The glass bead densities, that is, the densities of the finished material, were the same for each kind of briquet. Normalized random packing mass density was determined by dividing random packing mass density by the glass bead density and multiplying by 100%.
The random packing density of the unmodified pillow briquets was nearly 50%. The random packing density for the modified pillow briquets was only 43.6%. There was a nearly 12% reduction in the packing density of the modified pillow briquets.
This invention has been described herein in considerable detail to provide those skilled in the art with information relevant to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by different equipment, materials and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.
Claims
1. A modified charcoal briquet comprising:
- a pillow shaped charcoal briquet modified by Boolean geometric operations to yield a random packing density between about 35% and 46%;
- wherein the modified charcoal briquet comprises less volume than a pillow shaped charcoal briquet unmodified by Boolean geometric operations and having the same dimensions;
- wherein the random packing density for the modified charcoal briquet comprises about 0.70 times and 0.92 times the random packing density for the unmodified charcoal briquet.
2. The modified charcoal briquet of claim 1 wherein the random packing density for the modified charcoal briquet is between about 0.80 times and 0.88 times the random packing density for the unmodified pillow briquet.
3. The modified charcoal briquet of claim 1 wherein the random packing density for the modified charcoal briquet is between about 40% and 44%.
4. The modified charcoal briquet of claim 1 wherein the modified charcoal briquet comprises a first silhouette when viewed from at least one side that is identical to a second silhouette when viewed from at least one side of the unmodified charcoal briquet.
5. The modified charcoal briquet of claim 1 further comprising at least one lenticular groove on at least one face of the modified charcoal briquet;
- wherein the lenticular groove is approximately parallel to an edge of the modified briquet.
6. The modified charcoal briquet of claim 5 wherein the groove does not intersect with an edge of the modified briquet.
7. The modified charcoal briquet of claim 5 wherein the groove has a maximum depth and a maximum thickness, and the maximum depth is between about 0.15 and 0.25 times the maximum thickness.
8. The modified charcoal briquet of claim 7 wherein the maximum depth is between about 0.18 and 0.22 times the maximum thickness.
9. The modified charcoal briquet of claim 1 further comprising at least two lenticular grooves on at least one face of the modified briquet;
- wherein the lenticular grooves are approximately parallel to an edge of the modified briquet.
10. The modified charcoal briquet of claim 9 wherein the grooves do not intersect with an edge of the modified briquet.
11. The modified charcoal briquet of claim 9 wherein the groove has a maximum depth and a maximum thickness, and the maximum depth is between about 0.15 and 0.25 times the maximum thickness.
12. The modified charcoal briquet of claim 11 wherein the maximum depth is between about 0.18 and 0.22 times the maximum thickness.
Type: Application
Filed: Nov 10, 2005
Publication Date: Jun 29, 2006
Inventors: Scott Melin (Pleasanton, CA), Kelly Burke (Pleasanton, CA), Donald Swatling (Pleasanton, CA), Stevan Curtiss (Pleasanton, CA), Katie Chow (Pleasanton, CA)
Application Number: 11/271,339
International Classification: C10L 5/36 (20060101);