Patent Publication Number: US-3880611-A

Title: Artificial fireplace logs and method of producing

Description:
United States Patent Weiss Apr. 29, 1975 [5 ARTIFICIAL FIREPLACE LOGS AND 3.070.485 12/1962 Strickman 44/13 x METHOD OF PRODUCING I Primary Exuminer-C. Dees [76] Inventor&#39; gg i gg g&#39; j wgi Attorney, Agent, or FirmB. P. Fishburne, Jr.  
  Fayetteville, Ark. 72701 [57] ABSTRACT [22] Filed: Feb. 5, 1973 [52] US. Cl. 44/1 E; 44/10 A; 44/14; 44/38 [51] Int. Cl. C101 5/00; C101 5/36 [58] Field of Search 44/1 D, 1 E. 10 R, 10 A, 44/10 B, l4. 13, 38  
 [56] References Cited UNITED STATES PATENTS 764,072 7/1904 Perry et a1 44/10 B 1,199,999 10/1916 Lucas 44/10 B 1,454,410 5/1923 Robison 44/10 A 1,691,734 11/1928 Obcr 44/14 Unrefined, untreated wet or dry sawdust and Northern Kraft paper beater stock are thoroughly mixed in water contained in a tank. During mixing, a felting screen is lowered into the tank and the agitated mixture of sawdust and Kraft beater stock are drawn onto the screen by suction until a uniform layer is built up on the screen. Minute tentacles of the Kraft paper fi bers hold the sawdust particles together firmly without a chemical binder 0r adhesive. After removal of the screen from the tank and release of suction, the formed log is removed from the screen for drying and subsequent packaging. After drying, the logs are strong enough to withstand a moderate amount of rough handling.  
 6 Claims, 3 Drawing Figures ARTIFICIAL FIREPLACE LOGS AND METIIon or rnonucnvo BACKGROUND OF THE INVENTION The prior art has recognized the economic feasibility of using common sawdust for the production of fuel briquettes, artificial fireplace logs and the like. The prior art attempts to use the plentiful ingredient, sawdust, have to a great extent been stymied by the problems of refining the sawdust, drying and transporting, and more importantly the need for some sort of chemical binder in the successful formation of a log or the like. These problems have hindered to a great extent the successful use of sawdust on a commerical scale for making the types of fuel in question and generally such attempts have not been practical from an economic standpoint.  
  The present invention which successfully overcomes the known prior art deficiencies is founded on a discovery that the fibers of Northern Kraft paper and some other cellulosic fibers of the types used in making paper possess the ability when intermixed in proper proportions with unrefined, untreated sawdust to firmly lock and hold the sawdust particles together, thus com pletely dispensing with the necessity for a chemical binder or adhesive and for any pretreatment of the common wet or dry sawdust. In connection with the invention, it was noted that the Northern Kraft paper beater stock when suspended in water possesses many branches with minute tentacles extending out in all directions. Taking advantage of this physical phenomena, it was discovered that the mixing of proper amounts of unrefined sawdust and beater stock in water, followed by the suction application of the agitated mixture onto a suitable felting screen, will produce a felted layer of the desired shape whose integrity and strength can be maintained both before and after drying to produce an artificial log of the desired wall thickness, length and shape for the purposes contemplated. By this simple method, a commercially practical fuel product is achieved without encountering the seemingly insurmountable problems of the prior art which heretofore have prevented a completely successful usage of common wet or dry sawdust for the manufacture of fire place logs and the like.  
  Additional features of the invention and commercial advantages thereof over the prior art will become more apparent as the detailed description of the invention progresses.  
 BRIEF DESCRIPTION OF DRAWING FIGURES FIG. 1 is a greatly magnified elevational view of a small fragment of defibered Northern Kraft paper or beater stock.  
  FIG. 2 is a perspective view of fireplaces logs produced in the practice of the method.  
  FIG. 3 is a cross sectional view taken through a felting screen and a log body produced thereon by suction in the practice of the method.  
 DETAILED DESCRIPTION In accordance with the invention, approximately 240 pounds of unrefined, untreated, wet or dry sawdust, including vegetable matter, and approximately 48 pounds of Northern Kraft paper beater stock (fibers) are thoroughly mixed with water contained in a 300 gallon tank. While the mixture is undergoing agitation in the tank utilizing a conventional mixer apparatus, a cylindrical felting screen 10 attached to a conventional air hoist, such as a 30 inch stroke Curtis air hoist, is lowered into the mixture in the tank and a vacuum is applied through the screen to cause a uniform depositing of the sawdust and Northern Kraft paper fibers on the exterior of the screen in a roughly cylindrical layer 11. The felted layer 11 may be varied in thickness but for an artifical fireplace log 12, as illustrated in FIG. 2, having a length of about 24 inches and a 6 inch diameter, the thickness of the wall or layer 11 may satisfactorily be about 1 inch. The vacuum system employed in conjunction with the felting screen 10, the mixing apparatus, tank and air hoist are all conventional commerically available equipment components which require no illustration or description in the art to which the invention relates.  
  When the felted layer 11 has been developed to the desired thickness, the screen 10 is elevated from the mixing tank by the air hoist while the vacuum is maintained through the screen. The felted body or layer 11 at this time is preferably wrapped in a thin film of plastic, such as polyethylene, to further density the felted product and press out additional free water therefrom. Following this, the formed log is hand-removed from the screen 10 after the release of vacuum, and to assist removal positive air pressure may be applied internally to the screen by use of the conventional compressor and vacuum apparatus. The removed log, while still wet, will be capable of standing alone without collapsing or disintegrating. After air drying for a sufficient time, the vacuum formed logs gain enough strength whereby they will withstand a moderate amount of rough handling prior to packaging.  
  When a sufficient quantity of dried logs have accumulated, printed paper or cardboard end faces 13 are cemented to the ends of the tubular log bodies to simulate the annular growth rings of natural logs and to generally enhance the appearance of the product. The logs are now ready for packaging in practical numbers, such as three to a package. The packaged logs are loaded into corrugated cardboard boxes, 24 X 48 X 36 inches, each holding 30 packages, or logs, having a total weight of approximately pounds ready for shipment. Other packaging schemes may be employed, if preferred, and the above is merely a suggested econornical and practical packaging arrangement.  
  As previously noted, the essence of the invention which renders the method economically feasible and dispenses with the need for prior refinement of the common sawdust and the use of a chemical binder or adhesive for the sawdust is the using of the fibers 14 of Northern Kraft paper, FIG. 1, and taking advantage of the interlocking ability of the multitude of minute tentacles 15 which extend out from a main branch in many directions. These tentacles 15 entwine with and interlock with the sawdust particles and with other fiber tentacles in a pattern which causes the fibers to perform the function of a binder in firmly holding together the sawdust particles in the felted product.  
 While the invention has been described largely in I connection with the use of fibers of Northern Kraft bers commonly used in the making of paper. However, as discussed in connection with the description of the Northern Kraft paper fibers 14 having the many tentacles 15, Northern Kraft paper is the preferred material for producing the beater stock employed in the invention.  
  It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.  
 I claim:  
  1. The method of producing an artificial fireplace log comprising the steps of mixing unrefined sawdust and defibered paper in an approximate ratio of :1 by weight in water, vacuum depositing the mixture of sawdust and defibered paper onto a felting screen while agitating the mixture and building up on the screen a tubular artificial log body, removing the log body from the felting screen, and then air drying the log body thus formed.  
  2. The method as defined in claim 1, and the additional step of wrapping the tubular log body in a flexible plastic film while the log body is adhered to the felting screen to further densify the log body and remove free water therefrom.  
  3. The method of claim 1, wherein said defibered paper is Norther Kraft paper beater stock.  
 4. The product produced by the process of claim 1.  
  5. The method of producing an artificial fuel element for fireplace burning or the like comprising the steps of mixing and agitating unrefined sawdust and tentacled cellulosic fibers in the approximate ratio of 5:1 by weight in water, vacuum depositing the mixture of sawdust and tentacled fibers onto a screen to build up thereon said fuel element in an integrated stable form with said sawdust and fibers interlocked and bound solely by mechanical intertwining and interlocking of the fiber tentacles with sawdust particles, and removing said element from said screen and air drying it.  
 6. The product produced by the process of claim 5.