Gas burner

Abstract: There is provided a gas burner that is installed on a gas cartridge (11) containing combustible gas, and burns the combustible gas discharged from the gas cartridge (11), comprising a plug fitting (34) connected to the gas cartridge (11) for adjusting a flow of the combustible gas discharged from the gas cartridge (11), and a gas burning section (30) that burns the combustible gas fed through the plug fitting (34), characterized by that the plug fitting (34) is made of a durable metal, and a flange (34a) that is made from one of a light metal and a noncombustible light material, is positioned between the gas cartridge (11) and the plug fitting (34). The gas burner offers necessary durability and light weight without increasing the complexity of the manufacturing processes.

Description: The present invention relates to a gas burner. Figs. 1 and 2 show an example of a conventional gas burner known in the art. This example is concerned with a case in which a gas burner is used as a portable gas cooking stove. In Fig. 1, a portable gas cooking stove 10 is comprised of a gas cartridge 11 filled with compressed combustible gas, and a gas burner 12 mounted in a freely detachable manner on the gas cartridge 11. The gas cartridge 11 and the gas burner 12 are assembled in a hermetically sealed state using a gasket 13. The gas burner 12 is connected to the gas cartridge 11, and the connection is comprised of a plug fitting 14 through which combustible gas supplied from the gas cartridge 11 passes, a knob 15 connected to a gas flow adjusting spindle that adjusts the flow of the combustible gas flowing inside the plug fitting 14, by adjusting the degree of opening of a gas passage formed inside the plug fitting 14, a burner head 16 with a plurality of openings 16a in its surface, a mixing tube 17 connecting the plug fitting 14 and the burner head 16, and a plurality of kettle holders 18 installed on the mixing tube 17. This portable gas cooking stove is used as follows. Combustible gas in a pressurized state enters from the gas cartridge 11 into the plug fitting 14, and its flow is adjusted by the knob 15 connected to the gas flow adjusting spindle, and then the gas enters the mixing tube 17. The mixing tube 17 is provided with plural openings 17a, and by virtue of the negative pressure produced when the combustible gas passes through the mixing tube 17, external air is drawn into the inside of the mixing tube 17 through the openings 17a. The combustible gas is mixed with the air drawn in from the openings 17a, to form a gas mixture of combustible gas and air. The gas mixture enters the burner head 16, and then is discharged from the openings 16a and ignited by an appropriate means such as an electric igniter. Flames of the ignited, burning gas mixture heat an object to be heated (a pan, kettle, food, etc.) put on the kettle holders 18. Fig. 2 is a cross-sectional view of the interior of the plug fitting 14 (the kettle holders 18 are not illustrated). At the bottom of the plug fitting 14, a gas cartridge mounting hole 21, extending vertically, is provided, and female screw threads are cut in the inner wall of the gas cartridge mounting hole 21. Correspondingly, the gas cartridge 11 is provided with a mounting port 22 on which male screw threads are cut. The plug fitting 14 and eventually the gas burner 12 are installed on the gas cartridge 11 by screwing the mounting port 22 of the gas cartridge 11 into the mounting hole 21 of the plug fitting. A gasket 13 is placed between the gas burner 12 and the gas cartridge 11 when mounting the gas burner 12 on the gas cartridge 11 as described before. A gas flow adjusting hole 23 is provided inside the plug fitting 14, and extends horizontally. The gas flow adjusting hole 23 communicates with the mounting port 22 of the gas cartridge 11 through the first communication passage 24, and also with the inner chamber 17b of the mixing tube 17 through the second communication passage 25. A gas flow adjusting spindle 26 is assembled inside the gas flow adjusting hole 23. Female screw threads 23a are cut over a predetermined length from the open end of the gas flow adjusting hole 23, and the female screw threads 23a engage with the male screw threads 26a cut in the surface of the gas flow adjusting spindle 26. When the knob 15 connected to the gas flow adjusting spindle 26 is rotated in either direction, the gas flow adjusting spindle 26 moves forward (towards the left side of Fig. 2) or backward (towards the right side of Fig. 2) in the gas flow adjusting hole 23, while keeping contact with the inner wall of the gas flow rate adjusting hole 23. When the gas flow adjusting spindle 26 moves forward or backward, the size of the opening in the passage way between the first communication passage 24 and the second communication passage 25 varies, and the flow of combustible gas discharged from the gas cartridge 11 to the mixing tube 17 can be controlled. Obviously from the above description, the gas flow adjusting spindle 26 repeatedly moves forwards and backwards while contacting the inner wall of the gas flow adjusting hole 23. In other words, the female screw threads 23a of the gas flow adjusting hole 23 and the male screw threads 26a of the gas flow adjusting spindle 26 repeatedly engage with each other, and also the male screw threads of the gas cartridge 11 and the female screw threads of the gas cartridge mounting hole 21 are also repeatedly engaged and disengaged. Therefore, the plug fitting 14 must be made of a durable material. Consequently, brass has often been used conventionally for the plug fitting 14, because of its high durability. At this time, the flange 14a (see Fig. 1) has been also made of brass and has been an integral part of the plug fitting 14 and connects the plug to the gas cartridge 11, as a matter of course. However, reducing the weight of a gas cooking stove has been requested recently, so the material of the plug fitting 14 has been changed to a light metal such as aluminum, because a plug fitting 14 made of brass is heavy. However, if a the plug fitting 14 is made of aluminum only, its durability is poor, therefore brass sleeves 27, 28 have been inserted into the open ends of the gas cartridge mounting hole 21 and the flow adjusting hole 23. Female screw threads have been cut in the inner walls of these sleeves 27, 28, and the screw threads have engaged with the male screw threads of the mounting port 22 of the gas cartridge 11 and the male screw threads 26a of the gas flow adjusting spindle 26, respectively. However, aluminum is still used for the inner wall of the gas flow adjusting hole 23 which is in contact with the gas flow adjusting spindle 26, and for the first and second communication passages 24, 25 that repeatedly contact and separate from the gas flow adjusting spindle 26. As a consequence, the durability of the parts which are most important for adjusting the gas flow is not high. In addition, in order to insert the brass sleeves 27, 28, the parts with female screw threads, holes for them must be bored in the plug fitting 14, and then the brass sleeves 27, 28 must be manufactured separately. As such, the processes of manufacturing these components are complicated. DE 26 23 711 discloses a gas burner comprising a plug fitting attachable to a gas cartridge by use of threads. The gas cartridge comprises an outlet with a thread for attaching the plug fitting. The plug fitting comprises an inner thread for attaching the plug fitting to the outlet and an outer thread for attaching a fixing ring. The outside of the fixing ring is knurled and on the inside a thread for attaching the fixing ring to the outer thread of the plug fitting is provided. The fixing ring has a ring-shaped recess for receiving a ring-shaped disc. The plug fitting and the gas cartridge are connected in a sealed manner by means of an O-ring seal. The arrangement according to DE 26 23 711 is of considerable weight, since the material of the plug fitting and the fixing ring must be of the required strength for bearing the threads. Furthermore, the manufacturing process is complicated by providing threads on the inside and outside of the plug fitting and on the inside of the fixing ring. In view of the above-mentioned problems associated with a conventional gas burner, it is an object of the present invention to provide a gas burner with the required durability and lightness without increasing the complexity of the manufacturing processes. This object is solved by the gas burner of independent claim 1. Further advantageous features, aspects and details are evident from the dependent claims, the description and the drawings. The claims are to be understood as a first non-limiting approach to define the invention in general terms. The present invention relates to a gas burner which can be used as a so-called outdoor portable gas cooking stove, portable gas lantern, etc., and more particularly, to the plug fitting which is one of the components of a gas burner. There is provided a gas burner that is installed on a gas cartridge containing combustible gas, and burns the combustible gas discharged from the gas cartridge, including a plug fitting connected to the gas cartridge for adjusting a flow of the combustible gas discharged from the gas cartridge, and a gas burning section that burns the combustible gas fed through the plug fitting, characterized by that the plug fitting is made of a durable metal, and a flange that is made from a light metal or a noncombustible light material such as fiber-reinforced plastic, is slideably positioned between the gas cartridge and the plug fitting. In accordance with the above-mentioned gas burner, the durability required for the plug fitting can be ensured by making the plug fitting from a highly durable metal, and in addition, the manufacturing process for making separate threaded parts using a durable metal for the screw threads to be subject to high wear can be omitted. Furthermore with the gas burner invented herein, the flange that connects the plug fitting to the gas cartridge is formed separately from the plug fitting, and is made of a light metal. Because the flange need not be so durable as the screwed parts, it is not required to manufacture the flange from such a highly durable metal as the screwed parts. As described above, the gas burner according to the present invention is provided with a plug fitting whose body is made of a highly-durable metal, together with auxiliary portions other than the main body of the plug fitting manufactured completely from a light metal. Thereby, the required durability of the plug fitting can be assured while the weight of the plug fitting is also reduced. High-durability metals other than brass include iron and titanium. Available light metals are aluminum, magnesium, titanium, etc. The gas burner invented and herein described is applicable to any appliance in which combustible gas is burned. Typical applications of the gas burner according to the present invention are a portable gas cooking stove or portable gas lantern. The gas burner in accordance with the present invention offers the necessary durability and light weight without increasing the complexity of the manufacturing processes. The above and other aspects and advantageous features of the present invention will be made apparent from the following description made with reference to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the drawings. Fig. 1 is a front view of a conventional portable gas burner. Fig. 2 is a cross-sectional view of the portable gas burner illustrated in Fig. 1. Fig. 3 is a cross-sectional view of a gas burner in accordance with a preferred embodiment of the present invention. Fig. 4 is an exploded perspective view of a plug fitting used in the portable gas burner illustrated in Fig. 3. Figs. 3 and 4 show a preferred embodiment of the gas burner in accordance with the present invention. As illustrated in Fig. 3, a gas burner 30 in accordance with the embodiment includes a plug fitting 34 which is connected to a gas cartridge 11, and through which combustible gas supplied from the gas cartridge 11 passes, a knob 35 connected to a gas flow adjusting spindle assembled inside the plug fitting 34, a burner head 36 with a number of openings 36a formed in its surface, a mixing tube 37 connecting the plug fitting 34 to the burner head 36, and a plurality of kettle holders (not illustrated) installed on the mixing tube 37. This gas burner 30 is mounted on the gas cartridge 11 in a hermetically sealed state, through a gasket 13. A sealing O-ring 13b is located at the top of the inner wall of the gas cartridge mounting hole 21 provided at the bottom of the plug fitting 34. The burner head 36 and the mixing tube 37 constitute a gas burning portion. The inner structure of the plug fitting 34 is substantially the same as that of the plug fitting 14 shown in Fig. 2, except that in the case of the plug fitting 14 shown in Fig. 2, the flange 14a (see Fig. 1) for connecting the gas cartridge 11 and the plug fitting 14 is made of aluminum and is an integral part of the plug fitting 14, however with the invented gas burner 30, the plug fitting 34 and the flange 34a are formed separately from each other. As illustrated in Fig. 4, the plug fitting 34 is provided with a cylindrically shaped gas cartridge mounting portion 34b that extends downwards. On the inner wall of this gas cartridge mounting portion 34b, female screw threads (not illustrated) are formed which engage with the male screw threads on the outer periphery of the gas cartridge 11 mounting port 22, and an O-ring 13b is mounted above the female screw threads. The flange 34a engages with the gas cartridge mounting portion 34b of the plug fitting 34. The flange 34a is comprised of a guard portion 34c and a cylinder portion 34d, and a hole 34e is open through the center of the flange 34a, and penetrates the guard portion 34c and the cylindrical portion 34d. The diameter of the hole 34e is equal to the outer diameter of the gas cartridge mounting portion 34b. The gas burner 30 is mounted on the gas cartridge 11, with the gasket 13 placed on the outer periphery of the cylindrical portion 34d. In the gas burner 30, the plug fitting 34 is made of brass, and the flange 34a of aluminum. As described above, in the plug fitting 34 of the instant embodiment, the flange 34a is formed separately from the plug fitting 34, that is, the plug fitting 34 is made of brass and the flange 34a is made of aluminum, which is different from the plug fitting 14 in the conventional gas burner 10 known in the prior art and shown in Figs. 3 and 4. That is, in the embodiment of the present invention, the main body of the plug fitting 34 whose durability must be high is manufactured from a durable metal, e.g. brass, and the flange portion that does not need to be highly durable is formed separately from the plug fitting, and the flange portion 34a is made of aluminum, a light metal. In the gas burner 30 in accordance with the instant embodiment, the main body of the plug fitting 34 is made of brass while the flange 34a, an auxiliary part separate from the plug fitting 34 is manufactured using aluminum, a light metal, thereby assuring the durability required for the plug fitting and reducing the weight of the plug fitting at the same time. Although the plug fitting 34 is made from brass in this embodiment of the invention, the plug fitting 34 may also be manufactured using iron, titanium, etc. Materials applicable for the flange 34a include, in addition to aluminum, magnesium, titanium or other light metals, or a noncombustible light material such as a fiber reinforced plastic. Although the present embodiment of the invention disclosed the application of the invented gas burner to a gas cooking stove, the gas burner according to the invention can be applied also to a gas lantern.

Claims: A gas burner installable on a gas cartridge (11) containing combustible gas, for burning the combustible gas discharged from the gas cartridge (11) and comprising: a plug fitting (34) connectable to the gas cartridge (11) for adjusting a flow of the combustible gas discharged from the gas cartridge(11); and a gas burning section (30) that bums the combustible gas fed through the plug fitting (34), characterized in that the plug fitting (34) is made of a durable metal, and a flange (34a) that is made from one of a light metal and a non-combustible light material, is slideably positionable between the gas cartridge (11) and the plug fitting (34). The gas burner as set forth in claim 1, wherein the durable metal is one of brass, iron and titanium. The gas burner as set forth in claim 1 or 2, wherein the light metal is aluminum, magnesium or titanium. The gas burner as set forth in one of the preceding claims, wherein the noncombustible light material is fiber-reinforced plastic. The gas burner as set forth in any one of claims 1 to 4, wherein the gas burner is used as a gas cooking stove. The gas burner in any one of claims 1 to 4, wherein the gas burner is used as a gas lantern.

Inventors: IKARASHI TOSHIKAZU, YOKOYAMA HIROAKI, IKARASHI, TOSHIKAZU, YOKOYAMA, HIROAKI
Applicants: SNOW PEAK INC, SNOW PEAK, INC.
Application year: 1998
Main classification: F23D14
IPC codes: F24C3, F23D14