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  Gas fired heating device and a method of generating a flow of hot airUSPTO Application #: 20070231755Title: Gas fired heating device and a method of generating a flow of hot air Abstract: The invention relates to an apparatus for the heating of roofing material. The apparatus comprising: air supply means (86); an elongated tubular combustion chamber (10) with a first end (11) and a second end and having a wall (30) surrounding a longitudinal axis (A) of said combustion chamber (10) and including an exit for hot air at said second end (12) and at least one air entrance (50) near said first end (11) for delivery of a primary air flow. A burner arrangement is disposed essentially centrally within said combustion chamber near said first end. The burner arrangement comprises means for injection of fuel (88) and means for ignition of said fuel (80). The first end (11) of the combustion chamber being essentially air-tight, and said at least one air entrance (50) being located in the wall (30) of the combustion chamber (10) near said first end (11). The air entrance (50) comprises means to produce a helical current of air around said longitudinal axis (A) of the combustion chamber (10). The invention also relates to a method of generating a flow of hot gases in an apparatus for heating of roofing material (end of abstract) Agent: Darby & Darby P.C. - New York, NY, US Inventor: Jan Borst USPTO Applicaton #: 20070231755 - Class: 431005000 (USPTO) Related Patent Categories: Combustion, Process Of Combustion Or Burner Operation, Burning Waste Gas, E.g., Furnace Gas, Etc. The Patent Description & Claims data below is from USPTO Patent Application 20070231755. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] The invention relates to an apparatus for the heating of a bituminous roofing material, the apparatus comprising: air supply means; an elongated tubular combustion chamber with a first end and a second end having a wall surrounding a longitudinal axis of said chamber and including an exit for hot air at said second end and at least one air entrance near said first end for delivery of a primary air flow and a burner arrangement disposed essentially centrally within said combustion chamber near said first end, said burner arrangement comprising means for injection of fuel and means for ignition of said fuel. [0002] Many heating devices for domestic and industrial use require a heat source. When applying a bituminous roofing material on a roof, torches are directed at the bitumen layer of the material in order to make this layer soft and sticky so that the material will adhere to the surface to be covered. It is well known that torches producing a flame or a hot air stream for welding or other purposes may be the cause of injuries to persons or fires if a person or structure is exposed to the flame for a period of time. [0003] The provision of air chambers surrounding burner nozzles has been suggested to overcome this problem. For example, U.S. Pat. No. 3,883,290 discloses a burner where the generated stream of hot air is surrounded by an air current which insulates the wall of the guide pipe against heating. [0004] This device has a substantial disadvantage. Extensive heat is still developed in the area proximate to the ignition and burner arrangement. Therefore the burner and ignition arrangement has to be constructed from materials which are able to withstand these temperatures. Furthermore, no known material will last indefinitely if heated, and the expensive ceramic materials used in prior art apparatus are subject to thermal shocks and will therefore deteriorate thereby limiting the longevity of the system. [0005] The object of the invention is to solve the problem of high temperatures in the area proximate to the ignition and burner arrangement in a heating apparatus. [0006] The object of the invention is achieved by a heating apparatus provided with a first end being essentially air-tight and said at least one air entrance being located in the wall of the combustion chamber near said first end, the air entrance comprising means to produce a helical current of air around said longitudinal axis of the combustion chamber. The supply of air leaves the centre axis of the combustion chamber more or less unaffected by the surrounding helical current of air. This entails a relatively calm and rich burning of fuel along the centre axis of the combustion chamber. The centrifugal forces caused by the incoming air affect the cooler air stream with a higher density to the effect that it is thrown against the wall of the combustion chamber and cools it, while the hotter gas stream, with a lower density, is gathering in the core zone. [0007] According to a preferred embodiment, the at least one air entrance comprises an angled scoop, an angled hole or an angled tube. [0008] According to a preferred embodiment, said burner arrangement comprises fuel injecting means adapted to inject the fuel in a direction essentially concentrically with said longitudinal axis (A) of the combustion chamber (10). [0009] According to another preferred embodiment, the burner arrangement has wall means adapted to fit said apparatus to make said combustion chamber air-tight at said first end. Preferable the burner arrangement is releasably connected to the combustion chamber. This will facilitate access to the apparatus interior and thereby allow overall maintenance as well as easy renewal or replacement of worn parts. [0010] According to another preferred embodiment, the location of the air entrance is at or downstream of the means for injection of fuel. This will make the initial gas air mixture richer in gas and therefore it facilitates the ignition. [0011] The air entrance may preferably be at or downstream of both said means for injection of fuel and said means for ignition of said fuel. [0012] A further object of this invention is to provide a heating apparatus with improved heating effects and a flame-free stream of hot air having a great uniformity in the temperature profile at the outlet. [0013] This object of the invention is achieved by the apparatus further comprising means for introducing a secondary helical current of air, the secondary current of air having a direction of rotation opposite the direction of rotation for the primary air and being introduced further downstream the combustion chamber. The counter-flowing entering secondary air not only retards the helical motion and centrifugal effect, but it also slows down the formation of any excessive great axial velocity in the area of the core zone. The result is a flame-free stream of hot gases with a great uniformity in the diametric temperature profile at the outlet. The air entrance for said, at least one secondary airflow, can preferably be made as an angled scoop; angled hole or as an angled tube. [0014] In a preferred embodiment, the apparatus comprises a mixing chamber arranged in extension of said combustion chamber at said second end in which chamber the mixing of the counter-flowing currents of primary and secondary airflows takes place. This improves a better mixing of primary and secondary airflows. [0015] In a further preferred embodiment, the mixing chamber arranged in extension of said combustion chamber and the apparatus are releasably connected. By arranging the mixing chamber in extension of said combustion chamber and the apparatus being releasably connected, it is possible both to remove said mixing chamber for maintenance purposes and to change between different mixing chamber units which are made such that they are suitable for particular tasks. [0016] The apparatus may include a generally tubular housing surrounding said combustion chamber. This protects the operator against being charred or burned. [0017] According to a preferred embodiment, the housing is arranged at least partially spaced from the combustion chamber thereby defining an air gap for delivering secondary air, whereby the housing is maintained relatively cool during the operation of the apparatus. [0018] In a preferred embodiment the helical motion of the secondary air is accomplished by a helical spiral placed in the air gap bounded by the inside of the tubular housing and the outside of the combustion chamber. Preferably the air gap near said first end of the combustion chamber constitutes the initial air path for both primary and secondary airflows, said air path being subdivided into two separate air paths. This provides a more compact apparatus. [0019] The invention in other aspect provides methods as recited in claim 16-17. [0020] The methods facilitate the practical applications of generating flow of hot gases by way of providing both a relatively cool ignition area and a more efficient ignition inside the combustion chamber. [0021] The methods further facilitate the practical applications of generating flow of hot gases showing a great uniformity in temperature profile. [0022] Further objects and advantages and features of the invention appear from the following description of the preferred embodiments given with reference to the drawings wherein: [0023] FIG. 1 shows a heating apparatus assembly in a side view; [0024] FIG. 2a shows the inner barrier with a fixed helical element; Continue reading... Full patent description for Gas fired heating device and a method of generating a flow of hot air Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Gas fired heating device and a method of generating a flow of hot air patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Gas fired heating device and a method of generating a flow of hot air or other areas of interest. ### Previous Patent Application: Black and white photothermographic material Next Patent Application: Candle extinguishing device Industry Class: Combustion ### FreshPatents.com Support Thank you for viewing the Gas fired heating device and a method of generating a flow of hot air patent info. 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