Liquid fuel burner
United States Patent [191 Miyahara i 1 LIQUID FUEL BURNER (75] lnventor: Kingo Miyahara, Tokyo, Japan [73] Assignee: Kabushiki Kaisha Dowa, Tokyo,  
 Japan [22] Filed: May 13. 1974 1211 Appl. No.: 469,543  
 [30] Foreign Application Priority Data July 23. 1973 Japan it 48442995 {52} US. Cl. 431/168, 239/214.11 [51] Int. Cl. F23d 11/04 [58] Field of Search 431/168. 169; 239/21411, 239/2l4.l7  
 I56] References Cited UNITED STATES PATENTS 3.175.600 3/1965 Powcll 431/168 3.8111418 5/1974 Miyahara u 431/168 Primary Examiner-Edward G. Favors AIIUIHC), Age/i1. or FirmHill, Gross, Simpson, Van Sunten. Steadman. Chiara &amp; Simpson [57] ABSTRACT A liquid fuel burner provided with means for prevent- Apr. 1, 1975 ing overheating of an inner bottom wall of a main body, such means comprising an air ejection chamber interposed between an open end of a rotatable fuel gasifying member and a central opening of a gas chamber formed along an inner peripheral surface of the main body, and a cold air ejection gap formed between an outer peripheral portion of the open end of the fuel gasifying member and the air ejection chamber. Cold air is vigorously ejected from the air ejection chamber through the cold air ejection gap into the interior of the main body serving as a combustion chamber when liquid fuel is supplied to the rotatable fuel gasifying member and the combustion of fuel is started, so as to form an air curtain above the inner bottom wall to intercept the flames of combustion. An annular member is mounted at the outer peripheral portion of the open end of the fuel gasifying member and spaced apart therefrom by an atomized fuel blowing gap through which atomized fuel particles are ejected into the interior of the main body to ensure that liquid fuel in atomized particles is ejected through the fuel blowing gap. The cold air ejection gap may be formed in the air ejection chamber in a position disposed nearer to the inner bottom wall. so that the air curtain can be formed directly on the inner bottom wall.  
 4 Claims, 6 Drawing Figures PATENTEDAPR&#39; 1 ms szaman g FIG. 3  
  i-&#34;KEN 3.874.840  
 sum 3 95 g PATENTEDAPR 1 1975 saw u :15 z} LIQUID FUEL BURNER This invention relates to liquid fuel burners, and more particularly it is concerned with improvements in or relating to a liquid fuel burner for continuously burning a liquid fuel. particularly kerosene, in gasified form.  
  I have previously invented, a liquid fuel burner comprising a gas chamber formed in a peripheral portion of a main body of the burner along its inner peripheral surface, and a fuel gasifying member rotatably disposed at a central opening of the gas chamber and maintained in communication with the gas chamber, with an atomized fuel blowing gap being formed between the fuel gasifying member and the central opening of the gas chamber. Liquid fuel is first ejected in atomized particles through the atomized fuel blowing gap into the interior of the main body by the diffusing action of the fuel gasifying member and the action of a stream of air supplied under pressure so that the fuel may be burned in liquid form in the main body of the burner, and the liquid fuel supplied after combustion has begun is automatically gasificd by the fuel gasifying member and supplied to the gas chamber together with a stream of air supplied under pressure. Thus, the combustion of the gasified fuel is carried out in the interior of the main body through a combustion plate attached to the inner surface of the gas chamber.  
  In the aforementioned liquid fuel burner, the flames produced when the fuel is burned in liquid form or gas form intensively heat an inner bottom wall surface of the main hotly of the burner. If the main body of the burner is made of sheet iron and has a small thickness to reduce the weight and cost of the burner, the main body will be damaged and deformed by the heat produced by combustion. This will make it impossible to maintain the atomized fuel blowing gap between the fuel gasifying member and the gas chamber in proper relative positions. so that it will become impossible to sustain the combustion in an optimum condition over a prolonged interval of time.  
  The present invention obviates the aforementioned disadvantage of the prior art and provides a novel and useful liquid fuel burner.  
  Accordingly, a main object of the invention is to provide a liquid fuel burner which is provided with means for preventing overheating of the inner bottom wall surface of the main body of the burner whereby the damage to the inner bottom wall surface can be precluded which might otherwise be caused by the flames produced by the combustion of fuel in liquid form and gas form when the combustion of liquid fuel, particularly kerosene. is switched at once to the combustion of fuel in gas form.  
  Another object of the invention is to provide a liquid fuel burner which comprises an air ejection chamber interposed between the fuel gasifying member adapted to rotate in the main body ofthe burner and the central opening of the gas chamber disposed along the inner peripheral wall suface of the main body of the burner, the cold air introduced into the air ejection chamber being vigorously ejected into the interior of the main body of the burner through a cold air blowing gap formed between the peripheral portion of the open end of the fuel gasifying member and the air ejection chamher to form a cold air curtain above the inner bottom wall surface of the main body of the burner so as to thereby suppress the spreading of flames to the inner bottom wall. The provision of the cold air curtain is effective to prevent damage to the inner bottom wall of the main body of the burner which might otherwise be caused by the flames at the time of combustion of fuel in liquid form or in gas form, in case the main body of the burner is made of sheet iron or the like and has a small thickness.  
  Another object of the invention is to provide a liquid fuel burner of the type described in which the cold air introduced into the air ejection chamber is vigorously ejected directly along the inner bottom wall of the main body of the burner to produce a perfect air curtain on the inner bottom wall surface whereby the flames produced by the combustion of fuel in liquid form or gas form can be kept from damaging the inner bottom wall surface of the main body of the burner.  
  Still another object of the invention is to provide a liquid fuel burner ofthe type described in which the air ejection chamber is maintained in communication with the gas chamber and an air supply duct extending into the fuel gasifying member, so that the ejection of cold air can be carried out by employing part of the stream of air supplied under pressure to produce a fuel-air mixture.  
  Still another object of the invention is to provide a liquid fuel burner of the type described in which an an nular member is mounted at the peripheral portion of the open end of the rotatable fuel gasifying member, with an atomized fuel blowing gap being formed therebetween through which the liquid fuel can be ejected in atomized particles and scattered into the main body of the burner, whereby the liquid fuel can be positively converted into atomized particles and blown into the main body of the burner.  
  A further object of the invention is to provide a liquid fuel burner of the type described in which a plurality of agitation blades disposed in the fuel gasifying member are affixed to the annular member for providing an atomized fuel blowing gap, such agitation blades being effective to agitate the fuel gasified in the fuel gasifying member and the stream of air introduced under pressure thereinto so as to thoroughly mix them and produce a perfect air-gas mixture.  
  Additional and other objects and features of the invention will become evident from the description set forth hereinafter when considered in conjunction with the accompanying drawings, in which:  
  FIG. I is a longitudinal sectional view, with certain parts being cut out, of the fuel gasifying burner comprising one embodiment of the invention;  
  FIG. 2 is a sectional view taken along the line IIII of FIG. 1&#39;,  
  FIG. 3 is a plan view showing, on an enlarged scale, the fuel gasifying member in relation to the gas chamber;  
  FIG. 4 is a longitudinal vertical sectional view of the liquid fuel burner comprising another embodiment of the invention;  
  FIG. 5 is a sectional view taken along the line V-\&#34; of FIG. 4; and  
  FIG. 6 is a side view showing. on an enlarged scale. the fuel gasifying member in relation to the gas chamber as seen longitudinally.  
  The invention will now be described with reference to embodiments thereof shown in the drawings in which like reference characters designate similar parts.  
  The numeral 1 designates a main body of the burner made of sheet iron or the like and has a small thickness. It is formed with a flame blow off nozzle 2 in a central portion and a hollow gas chamber 3 in a peripheral portion along its inner peripheral surface. The gas chamber 3 is formed at its central portion with a central opening 5 at which an inner bottom wall 4 is bent inwardly. A combustion plate 6 is mounted on the inner peripheral surface ofthe gas chamber 3 so that a gasair mixture may be ejected therethrough into the interior of the main body I of the burner for combustion therein.  
  A rotary shaft 7 is inserted into the interior of the main body I ofthe burner and extends through the central portion thereof A fuel gasifying member 8 having a wire net 9 or like attached to its inner surface to promote vaporization and gasification of liquid fuel and to diffuse gasified fuel is directly connected at one end to the front end of the rotary shaft 7. The fuel gasifying member 8 is formed at the other end with an open end 10, with a cold air ejection gap 11 being formed between the open end of the fuel gasifying member 8 and the central opening 5 of the gas chamber 3.  
  The fuel gasifying member 8 has its open end 10 bent outwardly. and an annular member 12 of a suitable thickness is attached at several points to the outwardly bent end portion of the fuel gasifying member 8 through the wire net 9. so that an atomized fuel blowing gap 13 is formed between the outwardly bent end portion of the fuel gasifying member 8 and the annular member I2. The annular member 12 performs the functions of causing liquid fuel to be positively blown in gas form through the atomized fuel blowing gap 13 and preventing the produced gas from being ejected through the cold air ejection gap 1].  
  The numeral I4 is an air ejection chamber 14 disposed at an outer marginal portion of the central open ing 5 ofthe gas chamber 3 and maintained in communication with the cold air ejection gap II through ejection ports 15, so that streams of cold air can be ejected through the cold air ejection gap II to a position above the inner bottom wall 4. The air ejection chamber 14 is maintained in communication. through ventilation cylinders 17. with an air supply duct 16 extending through the gas chamber 3 and the fuel gasifying memher 8. so that part of the air supplied under pressure through the air supply duct 16 can be introduced into the air ejection chamber I4. If necessary. cold air may be supplied from a source different from the source of cold air supplied through the duct 16 and introduced into the air ejection chamber 14 through an air introducing tube I8 as shown in dash-and-dot lines in FIG. I. The numeral 19 designates air guide plates mounted on the inner surface of the air supply duct 16 in positions in which the ventilation cylinders I7 are connected to the duct 16. The numeral 20 designates a fuel supply tube opening at its forward end above a fuel diffusing member 21 attached to the inner surface of the fuel gasifying member 8. 22 is an ignition plug.  
  In the embodiment shown in FIG. 1. the fuel supply tube 20 may be dispensed with and the rotary shaft 7 may be in the form of a hollow shaft formed therein with a fuel delivery passageway 23. When this is the case. a number of fuel delivery grooves 24 may be formed on the surface of the fuel diffusing member 2] which is maintained in contact with the inner surface ofthe fuel gasifying member 8 so as smoothly to deliver (ill fuel to the inner surface ofthe member 8. The numeral 25 disignates a plurality of agitation blades each affixed at the base to the annular member 12 and extends along the inner wall surface of the fuel gasifying memher 8. The blades 25 perform the function of agitating and thoroughly mixing the gas produced in the liquid fuel gasifying member 8 and the stream of air supplied under pressure into the fuel gasifying member 8 so as to produce a perfect gas-air mixture.  
  The embodiment of the invention shown in FIG. I to FIG. 3 and described hereinabove can be made to achieve increased results in preventing overheating of the inner bottom wall 4 of the main body 1 of the burner when modified as shown in FIG. 4 to FIGv 6. More specifically. in the embodiment shown in FIG. 1 to FIG. 3, the streams of cold air ejected from the air ejection chamber 14 move all at once into the interior of the main body 1 of the burner through the cold air ejection gap 11 disposed adjacent the rotating fuel gasifying member 8, so as to thereby form a cold air can tain above the inner bottom wall 4 of the main body I of the burner. In this way. the flames produced by the combustion of fuel in liquid form or gas form can be intercepted and kept from approaching the inner bottom wall 4, so that the combustion of fuel in liquid form can be switched at once to the combustion of fuel in gas form without damaging the inner bottom wall 4 of the main body I ofthe burner. even ifthe latter is made of sheet iron or the like and has a small thickness.  
  On the other hand. the embodiment of the invention shown in FIG. 4 to FIG. 6 is more effective to preclude damage by the flames of combustion to the inner bot tom wall 4 ofthe main body 1 ofthe burner and to promote atomization ofliquid fuel. To this end. the burner is formed therein with a cold air ejection gap 26 which is interposed between the inner bottom wall 4 of the main body I and the air ejection chamber I4 arranged between open end I0 of the fuel gasifying member 8 and the central opening 5 of the gas chamber 3. so that the streams of cold air can vigorously move from the chamber 14 along the inner bottom wall 4.  
  The use of the aforementioned means enables a cold air curtain of a substantial thickness to be positively formed on the inner bottom wall 4 of the main body I of the burner even if the volume of cold air ejected is small. whereby damage to the inner bottom wall 4 which might otherwise be caused by the flames produced by the combustion of fuel in liquid form or gas form can be precluded. By this arrangement. it is possible to sustain the combustion of fuel in gas form in a satisfactory condition over an extended period of time even if the main body 1 ofthe burner is made of sheet iron and has a small thickness. In addition. it is also possible to start the combustion of fuel in liquid fortn and to switch it to the combustion of fuel in gas form at once without the atomized particle of liquid fuel ejected through the atomized fuel blowing gap 13 and scattered about being forcedly scattered by the streams of cold air ejected through the cold air ejection gap 26 or being cooled to delay ignition at the initial stages of starting of the combustion of fuel in liquid form.  
  In operation. if the rotary shaft 7 is rotated when the parts are in the condition shown in FIG. I to FIG. 3. then the fuel gasifying member 8, fuel diffusing member 21 and agitation blades 25 rotate in unison. Then. liquid fuel is supplied through the fuel supply tube 20 to the fuel diffusing member 21, and at the same time a stream of air is supplied under pressure into the fuel gasifying member 8 through the air supply duct 16. The fuel supplied to the diffusing member 21 in this way dif fused thereby moves onto the inner surface of the fuel gasifying member 8. The fuel is throughly diffused when it moves along the wire net 9 and ejected in an atomized fine particle form. through the atomized fuel blowing gap 13. into the interior of the main body 1 of the burner serving as a combustion chamber where it is ignited and burn.  
  Part of the stream of air supplied under pressure through the air supply duct I6 is ejected through the atomized fuel blowing gap 13 together with fuel. and the remainder of the stream of air moves through the gas chamber 3 and ejected through the combustion plate 6 into the interior of the main body 1 of the burner. so that the combustion of fuel in atomized liquid form in the interior of the main body I can be promoted. The combustion of fuel in liquid form intensively heats the fuel gasifying member 8. so that the fuel diffused and moving along the inner surface of the member 8 at this time and later on is quickly converted into gas form. The fuel in gas form is agitated by the agitation blades 25 and mixed with the air supplied under pressure. so that a gas-air mixture can be supplied under pressure into the gas chamber 3 and ejected through the combustion plate 6 into the interior of combustion chamber of the main body I for combustion therein. At the same time. part of the gasified fuel is ejected through the atomized fuel blowing gap 13 into the interior of the main body 1 for combustion therein.  
  On the other hand. the cold air introduced into the air ejection chamber l4 while the fuel is being burned in liquid form and also being gasified for combustion in gas form. is ejected all at once through the cold air ejection gap II and vigorously moves toward the inner bottom wall 4 so as to form a cold air curtain above or on the inner bottom wall 4 of the main body 1 of the burner. By this arrangement. the flames of burning fuel in atomized liquid form ejected through the atomized fuel blowing gap 13 and the flames of burning fuel in gas form ejected through the combustion plate 6 are intercepted and kept from reaching the inner bottom wall 4 by the presence of the cold air curtain. with a result that combustion takes place only in a zone of the interior of the main body 1 disposed above the air curtain. This cold air curtain keeps the inner bottom wall 4 from being damaged by the flames of combustion. so that combustion can be sustained satisfactorily over a prolonged interval oftime even if the main body of the burner is made of sheet iron and has a small thickness. Besides. cold air flows through the gap between the central opening 5 of the gas chamber 3 and the open end H) of the liquid fuel gasifying member 8. so that parts in the \icinity can be cooled and maintained in a proper condition.  
  The combustion plate 6 is formed therein with ejection apertures through which a fuel-air mixture is ejected in constant volume from the gas chamber 3 into the interior of the main body l forming a combustion chamber. Besides being made of sheet iron. it may be made of ceramics so that the gas-fuel mixture may be subjected to infrared combustion. It may merely be in the form of a punched plate.  
  From the foregoing description. it will be appreciated that the present imention permits. in virtue of the (ill aforementioned features. streams of cold air to be ejected into the interior of the main body 1 through the cold air ejection gap ll or 26 from the air ejection chamber 14 interposed between the central opening 5 of the gas chamber 3 and the rotating liquid fuel gasifying member 8, so as to thereby form an air curtain above or on the inner bottom wall 4 of the main body 1 of the burner. Thus, the flames produced when the fuel is burned in liquid form or gas form are intercepted and kept by the air curtain from reaching the inner bottom wall 4 of the main body 1, so that overheating of the inner bottom wall 4 can be prevented and combustion can be sustained over a prolonged interval of time. Therefore. even if the main body 1 of the burner is made of sheet iron or the like and has a small thickness. it can be kept from undergoing deformation and have a long service life. Besides, the cold air ejected from be tween the open end l0 of the liquid fuel gasifying member 8 and the central opening 5 of the gas chamber 3 performs the function of cooling these parts. thereby precluding deformation of the liquid fuel gasifying member 8 and permitting the same to rotate smoothly. The air is also ejected into the interior of the main body 1 to promote the combustion of fuel therein. ln addition. gasified fuel is immediately mixed with air by the action of the agitation blades 25 and the fuel-air mix ture produced is supplied to the gas chamber 3, thereby enabling the combustion of gasified fuel to be continued at a predetermined rate.  
 I claim:  
 I. A liquid fuel burner for burning liquid fuel by gasifying the same. comprising:  
 a main body made ofsheet iron or the like and having a small thickness;  
 a gas chamber formed along an inner peripheral surface of said main body and having a central opening;  
 a fuel gasifying member rotatably disposed in said central opening of said gas chamber and maintained in communication therewith; and  
 means for preventing overheating of an inner bottom wall ofsaid main body. said overheating preventing means comprising a cold air ejection gap formed between said fuel gasifying member and said central opening of said gas chamber. and an air ejec tion chamber disposed at a marginal portion of said central opening of said gas chamber and facing said cold air ejection gap so as to be maintained in communication therewith. cold air introduced from outside into said air ejection chamber being ejected through said cold air ejection gap into the interior of said main body whereby an air curtain can be formed above the inner bottom wall of said main body to intercept the flames of combustion and keep the same from reaching the inner bottom wall.  
 2. A liquid fuel burner for burning liquid fuel by gasifying the same. comprising:  
 a main body made of sheet iron or the like and a small thickness;  
 at gas chamber formed along an inner peripheral sur face of said main body and having a central open ing;  
 a fuel gasifying member rotatably disposed in said central opening of said gas chamber and maintained in communication therewith. said fuel gashaving ifying member being formed with an atomized fuel blowing gap at an end portion thereof; and  
 means for preventing overheating of an inner bottom 3. A liquid fuel burner as claimed in claim 1 charac terized by:  
 an annular member mounted at a peripheral portion of an open end of said rotatable fuel gasifying member, with a wire net or the like being interposed therebetween, to form the atomized fuel blowing gap between said fuel gasifying member and said annular member, to promote the diffusion and transfer of fuel.  
  4. A liquid fuel burner as claimed in claim 2 characterized by:  
 an annular member mounted at a peripheral portion of an open end of said rotatable fuel gasifying member. with a wire net or the like being inter posed therebetween, to form said atomized fuel blowing gap between said fuel gasifying member and said annular member, to promote the diffusion and transfer of fuel.