Abstract:
Combustible log (U) comprising a matrix (M), a first component (A) and a second component (B), the first and the second component (A, B) forming two inserts placed in the gangue forming matrix, the combustion of the first component (A) producing a first effect and the combustion of the second component (B) producing a second effect, the distances between the outer surfaces of the inserts and the outer surface of the matrix (M) being determined so as to introduce a time lag during the combustion of the log (U) between the apparition of the first effect and the apparition of the second effect.

Description:
TECHNICAL FIELD  
       [0001]    The present invention relates to a combustible log. The present invention relates in particular to a multi-effect combustible log comprising a matrix, a first component and a second component. 
       BACKGROUND OF THE INVENTION  
       [0002]    Combustible logs are known that are already used in particular for soot removing purposes, in particular according to U.S. Pat. No. 6,913,631. 
         [0003]    Generally, soot removing logs release gradually as they burn products that will deposit on the tars in order to treat them. All the active products contained in these logs are burned at the same time, which reduces considerably the efficiency of the treatment. 
         [0004]    Indeed, certain products that are supposed to have different actions create, once they are united, gaseous mixes that are not as efficient as when the different products are burned separately. Some products when burned together even cancel out their respective effects. 
         [0005]    Moreover, in the existing logs, the quantity of active product used remains limited. Inasmuch as the active product, for example in the form of a powder, is linked to the fuel, if too much is added, the log will no longer burn since the used active product or products slow down and reduce normal combustion. If the ratio of 25% of active products is exceeded, the log burns very badly and the treatment is of poor quality. 
         [0006]    Furthermore, it is desirable to be able to have logs that are so-called “Christmas logs” that burn with unusual colors. 
       DISCLOSURE OF THE INVENTION  
       [0007]    One aim of the invention is thus to propose a combustible log, designed for example for soot removing, that combines ease of use and improved efficiency for all the effects, for example the treatments, that are implemented by these means 
         [0008]    According to the invention, in a combustible log of the type defined previously the first and the second components form two inserts placed in the gangue forming matrix, the combustion of the first component producing a first effect and the combustion of the second component producing a second effect. The distances between the outer surfaces of the inserts and the outer surface of the matrix are determined so as to introduce a time lag during the log&#39;s combustion between the apparition of the first effect and the apparition of the second effect. 
         [0009]    The first insert can be in the vicinity of the matrix&#39;s center, the second insert being situated between the center of the matrix and its outer surface. 
         [0010]    Advantageously, the matrix comprises wood sawdust mixed with a binding agent. 
         [0011]    In a more advantageous manner, the binding agent used is stearic acid and/or sorbitan ester. 
         [0012]    The bonding agent can represent more than 25% by weight of the matrix. 
         [0013]    One at least of the components can include an element taken from the list comprising: lithium, strontium, carbon, thallium, boron, copper, barium, indium, zinc, potassium and/or a nitrate, chloride, carbonate, perchlorate or oxide from one element taken from the list comprising: lithium, strontium, carbon, thallium, boron, copper, barium, indium, zinc, potassium. 
         [0014]    The component can further comprise a halogenated compound. 
         [0015]    One at least of the components can be hygroscopic, odorous and/or insect repellant. 
         [0016]    One at least of the components can react with the tars, degrade the tars and/or color the tars. 
         [0017]    One at least of the components can be a wasp and/or bee repellent. 
         [0018]    The invention also proposes a method for obtaining a combustible log as previously mentioned, wherein the matrix is obtained by uniting two half cylinders. 
         [0019]    Advantageously, the two half cylinders are made by extrusion and/or by molding. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0020]    Other characteristics and advantages of the invention will appear in the following description of a preferred embodiment with reference to the attached drawings but without limiting character. In these figures: 
           [0021]      FIG. 1  is a perspective view of a combustible log according to the invention. 
           [0022]      FIG. 2  is a view at the end of the log of  FIG. 1 . 
           [0023]      FIG. 3  is a section according to a plane perpendicular to the axis of the log of  FIG. 1  during assembly. 
           [0024]      FIG. 4  is a view along the line IV-IV of  FIG. 3 . 
           [0025]      FIG. 5  is a view similar to  FIG. 4  of another embodiment of the log of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    With reference to  FIG. 1 ,  FIG. 2  and  FIG. 3 , a combustible log U according to the invention can be seen. The log U comprises a cylindrical matrix M in which grooves L 1 , L 2 , L 3  are provided, for example also of cylindrical shape. Profiles other than circular profiles are however also possible for the grooves within the frame of the invention. They can for example be square, rectangular or form a half-disc. 
         [0027]    The longitudinal axis of the grooves L 1 , L 2 , L 3  is for example parallel to the longitudinal axis of the matrix M. The extremities of the grooves L 1 , L 2 , L 3  are close to the extremities of the matrix M. The distance between the extremities of each groove and the extremities of the matrix M is preferably greater then or equal to the distance between the lateral walls of each groove and the lateral wall of the matrix M so that when the log burns, the component B is not released before or at the same time as the component A. According to another embodiment, the distance between the extremities of each groove and the extremities of the matrix is greater than or equal to the radius of the matrix. 
         [0028]    Other embodiments of the grooves are however possible within the frame of the invention. The grooves can in particular be oriented differently relative to the longitudinal axis of the matrix M. 
         [0029]    In order to facilitate the manufacture of the log U, the longitudinal axes of the grooves L 1 , L 2 , L 3  are preferably coplanar, which makes it possible, during the manufacture process, to form the matrix in two equal parts, symmetrical relative to a plane P in which lie the axes of the longitudinal grooves L 1 , L 2 , L 3 . 
         [0030]    According to another embodiment, not represented, the grooves are formed only in one of the two parts forming the matrix M. 
         [0031]    In the illustrated example, the grooves L 1  and L 3  are at the same distance to the lateral wall of the matrix M and contain the same component A. It is however conceivable within the frame of the invention to place the grooves L 1  and L 3  at different distances and/or to fill them with components different from one another. 
         [0032]    The matrix M is made from sawdust agglomerated by means of a bonding agent. One will preferably use as bonding agent stearic acid and/or sorbitan ester. The bonding agent represents about 25% by weight of the matrix M. 
         [0033]    Stearic acid has a lower melting point (about 70° C.) than paraffin (about 80° C.) and cools faster, which makes manufacture and molding easier. 
         [0034]    The combustion of these bonding agents is also more ecological than that of paraffin and generates only very little smoke. 
         [0035]    Finally, these bonding agents will disturb less the color effects caused by the burning of the log U in the case where one wishes to create a log having a decorative character by adding components whose combustion generates colored flames. 
         [0036]    Components A, B, for example in powder form packed by means of low-thickness carton (not represented) to form rolls or wrapped in rolls of carton and/or plastic, for example polypropylene, are placed in the grooves L 1 , L 2 , L 3 . 
         [0037]    In the frame of the invention, the nature of the components A, B as well as their packaging can be different. It could for example be agglomerated powder formed so as to allow it to be placed in the corresponding groove or grooves. According to another embodiment, the components are liquids packaged in pouches of plastic, for example of polypropylene. The components A, B can also be solid or liquid components placed directly in the corresponding groove or grooves. 
         [0038]    In the embodiment illustrated in  FIG. 4 , the grooves L 1 , L 2 , L 3  are parallel, but it would also be possible to contemplate many other arrangements.  FIG. 5  illustrates another embodiment where grooves L 4  and L 5  are placed orthogonally to the grooves L 1 , L 2 , L 3 . The distance between each groove and the outer wall of the matrix M is imposed by the time lag one wishes to establish before combustion of the component contained in the considered groove. The other parameters characterizing the positioning of each groove can be decided freely. However, it must be noted that arranging all the grooves in a same plane makes the manufacture of the log U easier. 
         [0039]    The components A, B are chosen according to the desired effect. Urea for example will be used for its ability to degrade tars. The invention thus allows choosing exactly which effects, for example which treatments, will be used and in what sequence they will be used. 
         [0040]    It is thus possible for example to have in a first step a hygroscopic component burn that will deposit on the walls of a chimney flue in order to attract humidity and humidify the walls, thus making them better capable of undergoing the treatment of a second active product degrading the tars, a treatment which is then greatly facilitated by the action of the first treatment. One could also, as a third treatment, have another component burn that will, in turn, have the effect of coloring the tars to allow a better visualization, by a professional and by the consumer, of the places where the treatment has been deposited in the chimney flue. 
         [0041]    One can also add any other component whose combustion generates a useful effect in the chimney flue, and notably perfumes in order to fight bad smells of tars in the summer time or repellent products against certain insects such as wasps and bees, to be burned in spring in order to avoid having wasp guests becoming then installed in the chimney flue. 
         [0042]    The invention is not limited to the field of soot removing. Many effects can be contemplated. In particular, it is possible to give the combustion of the log U a festive quality by obtaining colored flames. 
         [0043]    In order to obtain a colored flame, it is necessary to put in the grooves L 1 , L 2 , L 3  components A, B having particular emissive chemical elements. It is possible notably to use the following elements:
   Red: Lithium in many forms and notably metallic, nitrate, chloride, carbonate, perchlorate.
       Strontium: preferably in nitrate form (but also carbonate, sulfate and other salts). Strontium must be accompanied by a halogenated compound, mainly chlorinated so that the red develops at moderate temperature.   
       Yellow: Sodium in many forms. The emitted yellow is slightly orange.
       Carbon: many carbonated compounds give a yellow flame.   
       Green: Thallium gives the most beautiful green but is very toxic and must thus be excluded for domestic uses.
       Boron: many boron compounds give green, notably organoboron compounds such as alkylboranes, alkylboron ethers.   Copper: no or low halogenated copper salts can emit green.   Barium: halogenated barium salts emit a light green color. One can use either barium perchlorate or barium nitrate combined with a chlorinated compound. Barium is toxic.   
       Blue: Copper: the presence of a halogen such as chlorine or bromine is necessary. For example, any copper compound (oxide, carbonate) combined with a carbonated chlorinated compound such as hexachloroethane or polyvinyl chloride (PVC).
       Indium: many indium salts give a blue emission. The disadvantage of this element is its price.   Zinc: certain zinc salts emit a pale blue, but the emission can be degenerated by the presence of many substances.   
       Violet: Potassium. Many potassium salts emit a violet whose coloring power is much greater than its lighting power. Thus, a potassium salt emits a poorly perceptible color. On the other hand, the presence of potassium in a red emitting combination (on the basis of lithium or strontium) results in pink or purple through the effect of color combination.   White: The white emitted by a flame is the result of a balanced sum of all the colors. It is known that the reference white light is that of the sun, which the phenomenon of diffraction separates in its constituents (through the effect of a prism or of a rainbow). Thus, in order to reconstitute a white, it is necessary to recombine the colors in a balanced fashion. One can use for example 6/7 by weight of barium nitrate and 1/6 of strontium nitrate.
       An easier way of producing white is to use multi bond carbonated compounds such as acetylene or aromatic compounds. In this case, the difficulty is to achieve complete combustion, otherwise unappreciated black smokes will form.   
       
 
         [0058]    Intermediary colors such as the aforementioned pink, orange or blue-green are the result of combinations of several emitted colors. 
         [0059]    It is important to note that in emission, and notably as regards the color of the flame, the sum of the colors always lightens the colors up to white if the balance is perfect. 
         [0060]    It is the contrary of colors obtained in absorption, such as for example in the case of painting, where mixing always darkens the tones. The sum of all the colors in absorption results in black. 
         [0061]    The use of different grooves L 1 , L 2 , L 3  whose walls are placed at different distances to the outer wall of the matrix M allows here too to achieve differed effects and to cause flames of different colors to appear at different instants. 
         [0062]    For making the log U, one proceeds preferably in the following manner. 
         [0063]    One first of all makes two half-cylinders forming shells, by extrusion and/or molding of a volume of sawdust agglomerated by means of a bonding agent. 
         [0064]    According to one embodiment, the shells are first extruded and then the grooves are formed by molding one or both of the shells. According to another embodiment, the shells are only molded and the grooves L 1 , L 2 , L 3  necessary for inserting the components A, B are obtained directly during molding of the shells. 
         [0065]    The components A, B, for example packaged in a combustible material, for example a low-thickness carton (not represented), are then placed in the shells. 
         [0066]    The shells are then placed on one another to reconstitute a cylinder and glued by means of the used bonding agent. 
         [0067]    One can also conceive a wooden log that is cut in two to dig in it grooves that are filled with components before the log is closed again. 
         [0068]    All these logs, reconstituted or not, burn from the outside inwards. Thus, the products put in the outermost grooves are released first and those in the center last, the sequence of the sought effects is thus chosen, for example of the treatments one wishes the smoke flue to undergo. 
         [0069]    When in use, the log U is placed by the consumer on the embers or alone at the bottom of the fireplace in order to light it. 
         [0070]    During combustion, the different components A, B present in the log U are burned each in turn, in an order depending on the distance separating them from the surface of the matrix M, causing different treatments or effects. 
         [0071]    Thanks to this method, since the active products are not mixed directly with the fuel, it is possible to increase the quantity of active products without deteriorating either the combustion or the treatment. The combustible product used thus remains free of any combustion retardant. It is possible in this manner to exceed 50% of active products in the log U without tampering with its powers of combustion and to thus achieve effects, for example treatments, that are much more efficient.