Abstract:
A smoke producing system for efficiently producing reduced toxin smoke includes a heating chamber heated by a heat source. A coil passes into and through the heating chamber to deliver a smoke producing substance, typically a liquid, to the hottest portion of the heating chamber. The substance is heated above a flash point of the substance before it is released from the coil into the hottest part of the heating chamber where it is immediately converted to smoke. The smoke then passes from the hottest portion of the chamber through a convoluted path to an outlet port. In a particular embodiment, the smoke producing system incorporates a fan assembly used as the heat source and for directing the smoke produced in a desired direction.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application is a continuation of application Ser. No. 10/463,367, filed Jun. 17, 2003, now U.S. Pat. No. 6,865,341. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to smoke producers and more particularly pertains to a new smoke producing system for efficiently producing reduced toxin smoke. 
   2. Description of the Prior Art 
   The use of smoke producers and heating chambers is known in the prior art. U.S. Pat. No. 5,107,698 issued Apr. 28, 1992, to Gilliam describes a device and method for in situ testing of an internal combustion engine for vacuum leaks. Another type of smoke producer is U.S. Pat. No. 4,349,723 issued Sep. 14, 1982, to Swiatosz in which a smoke producing liquid is heated and sprayed into a heating chamber through an atomizing nozzle. U.S. Pat. No. 219,311 issued Sep. 2, 1879 to Salisbury discloses a coil steam boiler assembly showing structure for heating a liquid. U.S. Pat. No. 5,220,637 issued Jun. 15, 1993, to Levin III et al. discloses a smoke producing device that distributes smoke producing liquid onto the interior of a heated tube in the presence of a spiraling gas flow within the tube to heat the liquid for producing smoke that flows out of the top of the tube. U.S. Pat. No. 5,922,944 issued Jul. 13, 1999, to Pieroni et al. discloses a smoke producing apparatus that utilizes a heating element positioned above a supply of fluid that is incrementally injected towards the heating element by a tube extending through the fluid and drawing the fluid into the tube through an inlet opening when air is passed through the tube and out towards the heating element. U.S. Pat. No. 5,859,363 issued Jun. 12, 1999, to Gouge discloses a device that also uses a pool of fluid positioned in a smoke producing chamber below a heating element extending through the chamber. U.S. Pat. No. 5,753,800 issued May 19, 1998, to Gilliam discloses an apparatus for using smoke to test the exhaust system of an internal combustion engine. U.S. Pat. No. 6,439,031 issued Aug. 27, 2002, to Pieroni et al. discloses a method of smoke testing that utilizes the structure of the earlier describe Pieroni patent and a dye for facilitating identification of leakage points. U.S. Pat. No. 6,142,009 issued Nov. 7, 2000, to Loblick discloses another smoke producing device that utilizes an atomizing nozzle to introduce smoke producing liquid into a heated chamber. U.S. Pat. No. 4,764,660 issued Aug. 16, 1988, to Swiatosz discloses an electric portable device for heating a smoke producing liquid to produce smoke. U.S. Pat. No. 734,871 issued Jul. 28, 1903, to Hopwood discloses a steam generator structure. U.S. Pat. No. 736,652 issued Aug. 18, 1903, to Taboulevitsch discloses another steam producing structure. U.S. Pat. No. 4,330,428 issued May 18, 1982, to Clifford discloses a smoke generator that includes additional conduits for selectively flushing the device of ash and other accumulated particulate matter. U.S. Pat. No. 1,322,374 issued Nov. 18, 1919, to Trumble discloses another steam boiler structure. 
   While these devices fulfill their respective, particular objectives and requirements, the need remains for a device that produces large amounts of smoke in a highly efficient and clean manner to prevent the production of toxic by-products. 
   SUMMARY OF THE INVENTION 
   The present invention meets the needs presented above by providing a heating chamber heated by a heat source. A coil passes through the heating chamber to deliver a smoke producing substance to the hottest portion of the heating chamber. The substance is released into the chamber where it is immediately converted to smoke. The smoke then passes from the hottest portion of the chamber through a convoluted path within the chamber and out of an outlet opening. 
   An object of the present invention is to provide a new smoke producing system that fully combusts a smoke producing substance to reduce toxic by-products during smoke production. 
   Another object of the present invention is to provide a new smoke producing system that utilizes a superheating smoke production chamber to increase the quantity of smoke produced using a given amount of smoke producing substance. 
   Yet another object of the present invention is to introduce a smoke producing substance into a chamber heated above the flash point of the substance at the hottest area of the chamber to maximize smoke production. 
   Even still another object of the present invention is to reduce substance residue from the smoke producing substance by superheating the substance within the coil so that there is virtually no substance residue dispensed from the coil into the heating chamber. 
   Yet even another object of the present invention is to reduce substance residue from the smoke producing substance by dispensing the substance from the coil directly into the hottest portion of the heating chamber. 
   Still yet another object of the present invention is to reduce substance residue from the smoke producing substance by collecting any substance residue within the chamber to convert the substance residue to smoke before it can escape the chamber. 
   Yet even another object of the present invention is to maximize the length of coil within the heating chamber and maximize the distance the smoke travels within the heating chamber before being dispensed through the outlet opening. 
   To this end, the present invention generally comprises a heating chamber heated by a heat source. A coil passes into and through the heating chamber to deliver a smoke producing substance, typically a liquid, to the hottest portion of the heating chamber. The substance is heated above a flash point of the substance before it is released from the coil into the hottest part of the heating chamber where it is immediately converted to smoke. The smoke then passes from the hottest portion of the chamber through a convoluted path to an outlet port. 
   There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
   The objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
       FIG. 1  is a partial cut-away perspective view of a new smoke producing system according to the present invention. 
       FIG. 2  is a cross-sectional end view of the present invention. 
       FIG. 3  is a cross-sectional top view of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   With reference now to the drawings, and in particular to  FIGS. 1 through 3  thereof, a new smoke producing system embodying the principles and concepts of the present invention and generally designated by the reference numeral  10  will be described. 
   As best illustrated in  FIGS. 1 through 3 , the smoke producing system  10  generally comprises a heat source  12 , a heating chamber  20 , and a smoke producing substance  22  that is passed through the heating chamber  20  to produce smoke. 
   The heating chamber  20  includes first and second end walls  24  and  26  respectively. The first end wall  24  is heated by the heat source  12 . The heating chamber  20  includes an outer wall  28  extending between the first and second end walls  24 , 26  to define an interior  30  of the heating chamber  20 . 
   The heating chamber  20  also includes an inner wall  32  extending from the first end wall  24  into the interior  30  to define an inner chamber  34  and an outer chamber  36  within the heating chamber  20 . 
   A coil  38  is used to bring the substance  22  into the heating chamber  20 . The coil  38  includes a first portion  40  extending into the heating chamber  20 , a second portion  42  wrapping around the inner wall  32  and extending along a length of the inner wall  32 , and a distal portion  44  extending into the inner chamber  34 . The distal portion  44  of the coil  38  includes an open end  46  positioned adjacent to the first end wall  24 . 
   The substance  22  is typically a fluid  48  designed for producing smoke when the fluid  48  is heated above a flash point of the fluid  48 . The flash point is defined as the temperature at which the fluid  48  changes into smoke at substantially atmospheric pressure. The fluid  48  is passed through the coil  38  and into the inner chamber  34  of the heating chamber  20  such that the fluid  48  is heated above the flash point, preferably while it is within the coil  38  where the limited volume of the coil  38  prevents immediate smoke formation and increased pressure urges the fluid  48  out of the coil  38 . Thus, smoke is produced within the inner chamber  34  when the fluid  48  is passed through the open end  46  of the coil  38 . 
   The outer wall  28  includes an outlet opening  50 . Thus, the smoke produced in the inner chamber  34  is emitted from the heating chamber  20  through the outlet opening  50  after expanding and moving through the inner and outer chambers  34 , 36 . 
   The above structure is sufficient to produce very low residue smoke but heating of the heating chamber  20 , coil  38  and thus the substance  22  within the coil  38  is increased by addition of a medial wall  52  extending from the second end wall  26  into the interior  30  of the heating chamber  20 . The medial wall  52  is positioned between the inner wall  32  and the outer wall  28  to define inner and outer portions,  54  and  56  respectively, of the outer chamber  36 . The medial wall  52  includes an open end  58  adjacent to the first end wall  24 . Thus, the substance  22  is dispersed into the hottest portion of the heating chamber  20  and smoke produced in the inner chamber  34  must pass into and through the inner portion  54  of the outer chamber  36  before passing into the outer portion  56  of the outer chamber  36 . This convoluted pathway retains the smoke inside the heating chamber to increase the exposure to heat to maximize the burning of any potential residue from the conversion of the substance  22  to smoke. This also serves to assist in smoke production and complete use of the smoke producing substance even when the substance is initially dispensed as the heating chamber is being heated. Thus, any residue collected before the heating chamber reaches maximum temperature is retained and burned to produce smoke. 
   The outlet opening  50  is positioned proximate the first end wall  24 . Thus, the smoke must additionally pass along substantially a full length of either the outer portion  56  of the outer chamber  36  when the medial wall  52  is present or the full length of the outer chamber  36  when the medial wall  52  is not present before being emitted through the outlet opening  50 . This again serves to retain the smoke within the heating chamber  20  to maximize exposure to heat above the flash point to completely burn the substance and any potential residue. 
   A nozzle  60  is coupled to the outer wall  28  around the outlet opening  50  for directing the smoke emitted through the outlet opening  50  in a desired direction. In an embodiment, the nozzle  60  is fixed and substantially L-shaped for directing the smoke downward for reasons described below. 
   A lowermost edge  62  of the outlet opening  50  is positioned in a spaced elevation above a bottommost surface  64  of the interior of the heating chamber  20  for collecting any residual liquid  66  in the heating chamber  20  to prolong heating of the liquid  66  and minimize emission of the liquid  66  through the outlet opening  50 . This structure is designed so that the liquid  66  is retained in the heating chamber  20  to increase exposure of the liquid  66  to high heat to enhance full vaporization or burning off of the liquid  66 . The above structure has been found to drastically reduce residual liquid to an extremely low level, thus greatly increasing the amount of smoke produced per unit of the substance  22  and greatly enhancing the efficiency of smoke production. 
   Although the above heating chamber may be applied to any use where smoke production is desired the smoke producing system of the present invention has been applicable to testing conduits for leaks, particularly sewer and drainage pipes and systems. For such systems, the heat source is derived from a fan assembly  68 . The heating chamber  20  is positioned adjacent to an engine at a hot point such as in close proximity to the exhaust pathway. The engine may be designed to deliver or concentrate heat. The outlet opening  50  is positioned to emit the smoke into a stream of air produced by the fan assembly  68 . The fan assembly  68  includes a skirt portion  70  designed for fitting over a manhole opening  2 . The fan assembly  68  includes a fan blade  72  that is positioned directly into the manhole opening. The fan blade is further positioned adjacent to a distal opening of the nozzle so that the outlet opening  50  and the stream of air created by the fan blade are directed to send the smoke through the manhole opening. 
   For the particular use of emitting smoke into a sewer or drainage pipe system through a manhole opening, the fan assembly is placed over the manhole opening such that the fan blade is positioned in the manhole opening. A container of the smoke producing substance is connected to the first portion of the coil where a standardized quick connect mechanism may be employed. A primer mechanism is used to draw the substance into the coil. The fan assembly is started and begins producing heat. The heating chamber is coupled directly to the fan assembly such that the first end wall is heated directly by the heat from the fan assembly. The substance within the coil is superheated beyond the flash point and the smoke is produced upon the substance exiting the coil within the inner chamber. The smoke is then emitted through the outlet opening where it is put to the desired use. 
   With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
   Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.