Patent Application
20130212936
The present invention relates to a process and apparatus for manufacturing a composited fire log resulting therefrom.
Commonly available composite fire logs and fire starter logs mainly comprise only one or two dry materials with wax or binders processed under very high pressures at generally ambient temperature These types of composite fire logs are limited as to their possible BTU output as well as possible raw materials and moisture content of the raw materials.
Accordingly, there is a need for a process for making composite fire logs and fire starter logs that does not require high pressures, that may use raw materials with high moisture content, which characteristically have not been used due to their low BTU value or cost of drying materials, while having a high BTU output.
The present invention relates to a method of manufacturing a composite fire product, comprising:
The present invention further relates to an apparatus for manufacturing a composite fire product, comprising:
Embodiments of the invention will be described by way of example only with reference to the accompanying drawing, in which:
Generally stated, the non-limitative illustrative embodiment of the present invention provides for the manufacturing of a composite fire product using low BTU components having high moisture content. The non-limitative illustrative embodiment also provides for a low pressure apparatus that may be used for the manufacturing of the composite fire product. The resulting product is a dense composite fire product with a high BTU output. This is due to the combination of cellulose containing materials, blending dry materials with higher moisture content raw materials under high flash heat allowing the materials to flow more like liquids, form an adhesive interacting between the various components and combine to produce a uniform composition.
It is to be understood that the term “composite fire product” as used throughout the following description is not meant to be limitative and that it may also apply to other composite fire products such as, for example, fire logs, fire starter logs, pellets, etc.
Referring to
The process 10 starts at block 12 where the various materials are mixed. The materials that may be used include wax (e.g. vegetable wax such as rice, palm, soy wax, advantageously having a melting point greater or equal to 100° F., or paraffin wax with similar properties), cardboard (wax cardboard and other waste paper), grains and spices, green residue waste (e.g. coffee grinds, tea leaves, sunflower hulls and stocks, waste flowers, soy bean hulls and stocks, straw (such as wheat, barley, oats, and soragum), citrus fruit peels, corn starch, stocks, husks, and cob; grass (hay), sugar cane (or similar large grass species) and saw dust or wood residues (softwood, hardwood, wood waste trimmings; leaves and components from spice plants, aromatic trees like cinnamon and evergreen trees in order to provide additional nature scent). The materials may also include waste streams containing high moisture content (i.e. greater or equal to 15%) from paper such as industrial pulp and paper waste, wax boxes, failed quality paper and wax paper batches. Further materials that may be used include industrial food baking raw materials that have failed quality control testing (flour, sugar, starch additives), as well as waste streams from the brewing industry.
It is to be understood that other materials with characteristics similar to the materials mentioned above may also be used.
In a first illustrative embodiment of the present invention, the materials include wax, at least one non-dry material having high moisture content (from 15 to 50%) and at least one dry material, with either or both the non-dry and dry materials containing cellulose.
In a second illustrative embodiment of the present invention, the proportion of each material may vary as follows:
In a third illustrative embodiment of the present invention, the proportion of each material may vary as follows:
The dry materials are first mixed (i.e. cardboard, dry green residue waste, saw dust, wood, etc.) in no specific order. The wax can be dry and added to the dry material mix or melted and then added to complete the composition. The non-dry materials can be added to the wax and heated, mixed, and kept at a temperature greater or equal to about 100° F. until used in the mix.
At block 14, the mixed materials are blended to provide a consistent composition at ambient or elevated temperature (greater or equal to about 100° F.). The blending time, commonly from 5 to 30 minutes, is based on the specific materials in the mixture.
Then, at block 16, the composition is compressed and heated. The composition is compressed using, for example, a screw extruder or a packed compression device, at a pressure ranging from about 500 psi to 25,000 psi; advantageously under about 5,000 psi, depending on the composition and desired product (e.g. an easy to light fire starter having a lower density, a long lasting fire log having a high density, etc.). The temperature during the compression is advantageously kept greater or equal to about 100° F. and depends on the composition and the desired product as the core of the composition should be at a temperature greater or equal to about 120° F. The temperature typically ranges from about 100 to 400° F. The high temperature allows for the extraction or release of the natural binder in the green residue waste and wood residue components, and the pressure provides for a fluidity of the components to allow for a production a single mix component at the end of the process 10. The combination of high temperature with the mixture allows the use of lower pressures to produce higher density components at greatly reduced energy input. The pressure and temperature are applied to the mixed materials at flash times (i.e. below one minute).
At block 18, the compressed composition is extruded while being heated if a low density product is desired (for example to be formed into a specific shape by a further process) or cooled if a higher density product is desired (the cooling providing for an instant adhesive effect of the components). During the heated extrusion process, the temperature may range from 50 to about 75° F., the temperature varying with the size of die used in the extrusion, the components used in the composition and the desired density. During the cooled extrusion process, the temperature may range from ambient temperature to about 32° F., the drop in temperature varying with the size of die used in the extrusion, the components used in the composition and the desired density. The pressure and temperature are applied to the composition at flash times (i.e. below one minute). The conclusion of this step results in the composite fire product with a density varying according to the temperature at which the composition was extruded.
Finally, at block 19, as an optional step, the shape of the composite fire product may be modified depending on its intended use. As high density logs are harder to light than low density ones, at least one of the extremities of the composite fire product may be cut at an angle, for example between about 10 and 80°, so as to acts like a wick on a candle. This allows even a dense composite fire product to light easily. In an alternative illustrative embodiment, the composite fire product has at least one of its extremities cut at a 45° angle.
Because of the pressures used, the output of the composite fire product manufacturing process 10 may range up to 10 tons per hour while previous manufacturing methods using higher pressures in excess of 20,000 psi, and comparable capacity apparatuses, provide for only up to 1.5 tons per hour.
It is to be understood that as the diameter of the produced composite fire product increases, the duration of the compression and heating/cooling steps (steps 16 and 18), as well as the pressures applied, will need to be adjusted relative to the diameter of the desired composite fire product so as to allow for the temperature of its core to be consistently greater or equal to about 120° F.
Typical composite fire products manufactured in accordance with the composite fire product manufacturing process 10 of
It should be noted that the composite materials of the composite fire product burn as one unit similarly to a coal briquette, not like the prior art products such as fire logs, which expand and break up while burning. Also, the use of wax in the composition and the processing of the components of the composition provide for composite fire products that are waterproof, therefore minimizing oxidation of the green residue materials. Also, the burning characteristic of the composite fire product allows for a more complete burning of the composite materials due to the increase BTU output (temperatures greater than 700° F.), which provides for a cleaner burn than firewood and leave less ash unlike prior art products.
It is to be understood that although the composite fire product manufacturing process 10 herein described allows the use of low pressures, it may also be used at high pressures as well.
Referring to
The blending unit 120 is adapted to receive the mixed materials and is provided with a blending mechanism 122, a conveyor 124 and a heating element 126. The conveyor 124 provides the blended composition of materials to the composition receiving unit 130.
The composition receiving unit 130 is adapted to receive the composition from the conveyor 124 and is provided with a feeding mechanism in the form of a feed screw 132, which activated by motor 134, and a heating element 136. The action of the feed screw 132 moves the composition into the first pressure chamber 140.
The first pressure chamber 140 comprises a pressurizing mechanism in the form of compression screw 142, which is also activated by motor 134, and a heating element 144. The speed of the motor 134 and the configuration of the compression screw 142 may be adjusted in order to control the pressure applied to the composition. It is to be understood that the dimensions of pressure chamber 140 also have an effect on the pressure. The action of the compression screw 142 moves the heated and pressurized composition into the second pressure chamber 150.
The second pressure chamber 150 comprises an extrusion output in the form of a die 152, through which the composition is extruded, and includes a temperature adjustment mechanism in the form of heating/cooling element 154. The die 152 may be adjusted depending on the desired product (e.g. fire log, fire starter log or pellet).
Optionally, the extrusion output may further include a slicing mechanism so as to cut at least one of the extremities of the composite fire product at an angle.
It is to be understood that, although not shown, the composite fire product manufacturing apparatus 100 also includes controls and power supply appropriate for its functioning, as known by a person skilled in the art.
Although the present invention has been described by way of particular embodiments and examples thereof, it should be noted that it will be apparent to persons skilled in the art that modifications may be applied to the present particular embodiment without departing from the scope of the present invention.
The present application claims the benefits of U.S. provisional patent application No. 61/272,127 filed Aug. 19, 2009, which is hereby incorporated by reference.
