Burner for portable gas cooking stove

Abstract: There is provided a burner to be used for a portable gas cooking stove, comprising (a) a mixture gas pipe (26) having an open end through which a mixture gas of combustible gas and air is exhausted, (b) a burner head (25) connected to the mixture gas pipe (26) in a hermetically sealed condition and having openings (25a) at a surface thereof, through which the mixture gas blows out, and (c) an igniter (28) igniting the mixture gas, characterized in that the igniter generates spark in a direction perpendicular to a flow of the mixture gas blowing out through the opening (25a) of the burner head. The burner makes it possible for spark to make contact with mixture gas flow in a larger contact area than that of a conventional burner. Accordingly, it is possible to stably ignite mixture gas, even if the mixture gas has a great flow velocity.

Description: The present invention relates to a so-called outdoor portable gas cooking stove, and more particularly, to a burner structure of a portable gas cooking stove. Fig. 1 shows an example of a portable gas cooking stove known in the art. Normally, the portable gas cooking stove 10 includes a gas cartridge 11 filled with compressed combustible gas, and a gas burner 12 mounted detachably on the gas cartridge 11. The gas cartridge 11 and the gas burner 12 are coupled to each other in a hermetically sealed condition through a gasket 13. The gas burner 12 is comprised of a plug fitting 14 which is connected to the gas cartridge 11 and through which combustible gas supplied from the gas cartridge 11 passes, a gas flow adjusting spindle 15 which adjusts a degree of opening of a gas passage formed inside the plug fitting 14 to thereby adjust a flow of the combustible gas passing through the plug fitting 14, a burner head 16 with a number of openings 16a formed on a surface thereof, a mixing tube 17 connecting the plug fitting 14 to the burner head 16, kettle holders 18 that are fixed on the mixing tube 17 and extend over the burner head 16, and an igniter 19 mounted on a support 19a. The combustible gas is filled in the gas cartridge 11 in a pressurized condition. Hence, when the gas passage is made open by the gas flow adjusting spindle 15, the combustible gas in a pressurized condition enters the mixing tube 17 from the gas cartridge 11 through the plug fitting 14. Thus, the combustible gas enters the mixing tube 17 with a gas flow thereof being adjusted by the gas flow adjusting spindle 15. The mixing tube 17 is formed with a number of openings 17a (only one of them is illustrated in Fig. 1). External air is absorbed into the mixing tube 17 through the openings 17a by virtue of negative pressure produced when the combustible gas passes through the mixing tube 17. The combustible gas is mixed with air entering the mixing tube 17 through the openings 17a, into a gas mixture of the combustible gas and air. After the gas mixture enters the burner head 16, the gas is discharged through the openings 16a, and is ignited by the electric igniter 19 located in the vicinity of the burner head 16. Flame of burning gas mixture heats an object to be heated such as a pan, kettle, food, etc., put on the kettle holders 18. In general, outdoor appliances, not limited only to portable gas cooking stoves, are required to be small. Regarding a portable gas cooking stove, the gas cartridge 11 cannot be fabricated smaller in size than a practical limit determined to ensure a volume of gas to maintain a gas-burning time required for practical use. Consequently, in a portable gas cooking stove, miniaturization has been focused mainly on the gas burner 12, and more particularly, on the burner head 16. However, if the burner head 16 is simply reduced in size, a flow of the gas mixture may exceed the proper gas burning rate, because a volume of the burner head 16 becomes smaller relative to a gas flow from the gas cartridge 11, resulting in a greater rate of the gas mixture discharged through the openings 16a of the burner head 16. If the mixture gas is discharged at a great rate, the mixture gas is rarely ignited by virtue of spark generated by the igniter 19, resulting in incomplete combustion of the mixture gas. In addition, in the gas burner illustrated in Fig. 1, the igniter 19 is supported only by the support 19a, resulting in that the igniter 19 cannot be stably fixed relative to a gas flow of the gas mixture discharged through the openings 16a. This also causes incomplete combustion of the mixture gas. In US 5,573,393 a gas burner is described which comprises a piezo-electric device generating a spark for igniting the combustible gas. Also, in WO 98/09114 a gas burner comprising an igniter is described, wherein said igniter is disposed in an ignition space within the burner head. Further to this, EP 0 703 409 Al descibes a gas burner comprising a gas flow conduit extending through a flame zone of the burner so that the gas is preheated before burning. The present invention intends to overcome the above problems. The object is solved by the burner according to independent claim 1. Further advantages, features, aspects and details of the invention are evident from the dependent claims, the description and the accompanying drawings. The claims are intended to be understood as a first non-limiting approach of defining the invention in general terms. The present invention generally relates to a portable gas stove. In particular, it relates to the burner of a portable gas stove. It is therefore an object of the present invention to provide a burner which is capable of stably igniting mixture gas discharged from a burner head, and/or is capable also of stably supporting a igniter to thereby ensure ignition of mixture gas. There is provided a burner to be used for a portable gas cooking stove, including (a) a mixture gas pipe having an open end through which a mixture gas of combustible gas and air is exhausted, (b) a burner head connected to the mixture gas pipe in a hermetically sealed condition and having at least one opening at a surface thereof, the mixture gas blowing out through the opening, and (c) an igniter igniting the mixture gas blowing out through the opening of the burner head, characterized in that the igniter generates spark in a direction perpendicular to a flow of the mixture gas blowing out through the opening of the burner head. As illustrated in Fig. 1, the igniter 19 is positioned facing the burner head 16 in the conventional burner. Accordingly, the igniter 19 generates spark in parallel with a flow of a mixture gas discharged through the openings 16a of the burner head 16. Thus, a contact area between the spark and the mixture gas flow is relatively small. As a result, if the mixture gas had a great velocity, it was difficult to ignite the mixture gas by spark generated by the igniter 19. In contrast, the burner in accordance with the present invention includes an igniter which is positioned perpendicularly to a flow of mixture gas discharged through openings of a burner head. As a result, spark is generated in a direction perpendicularly to a flow of mixture gas. Hence, a contact area between spark and a flow of mixture gas in the burner in accordance with the present invention is greater than the same in the conventional burner illustrated in Fig. 1. Hence, the burner in accordance with the present invention makes it possible to stably ignite mixture gas, even if the mixture gas has a great flow velocity. It is preferable that the igniter is supported at lower and upper ends thereof by the mixture gas pipe. It is preferable that the burner further includes an igniter cover in which the igniter is accommodated. The igniter cover is designed to have a projecting portion projecting in a direction, the projecting portion being formed with an opening having a diameter almost equal to a diameter of the mixture gas pipe. Preferably, the igniter cover is fixed relative to the mixture gas pipe by engaging the projecting portion to the mixture gas pipe. The igniter may be comprised of (a) a base block extending in a first direction, (b) a pillar extending in a second direction perpendicular to the first direction, (c) an igniter section extending from a summit of the pillar, and (d) a switch preferably movable in the first direction, and the igniter cover may be comprised of (a) a first cover portion covering the base block therewith, and (b) a second cover portion covering the pillar therewith. It is preferable that the first cover portion has a portion located above the switch and bent upwardly and obliquely. It is preferable that the igniter is supported by the mixture gas pipe through a igniter support which is comprised of a ring engageable to the mixture gas pipe and a projection fittable into the second cover portion of the igniter cover, the projection being formed with an opening into which the pillar is to be fit. It is preferable that the burner further includes a generator comprised of a pipe through which the combustible gas flows, the generator being arranged outside and close to the burner head. Combustible gas supplied from the gas cartridge passes through the generator, and then, passes through the mixture gas pipe, and is mixed with air into mixture gas while passing through the mixture gas pipe. Since the generator is located close to the burner head, the generator is heated by burning mixture gas blowing out of the burner head. Accordingly, the mixture gas passing through the generator is also heated, and is discharged from the burner head at high temperature. Mixture gas of combustible gas and air at higher temperature is more likely to be ignited. Thus, the mixture gas which has been heated during passing through the generator can be readily ignited by spark generated by the igniter. It is preferable that the igniter generates spark between the burner head and the generator. By arranging the burner head, the generator and the igniter in this order, these three parts can be arranged in a smallest space, ensuring reduction in a size of the burner. It is preferable that the generator is reverse U-shaped, and that the igniter is positioned surrounded by the generator when viewed from a front of the generator. By arranging the igniter within the generator, the generator acts as a windscreen for the igniter. As a result, a flow of the mixture gas discharged through the openings of the burner head can be stabilized, ensuring stable ignition of the mixture gas. It is within the scope of the invention that the igniter generates spark within a range of 70°- 110° to a flow of the mixture gas blowing out through the opening of the burner head. Preferably, the range is 80° - 100°. Most preferably, the igniter generates sparks in a direction about perpendicular to the flow of the mixture gas. Even more preferably, the igniter generates spark perpendicular to the flow of the mixture gas. The invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: Fig. 1 is a front view of a conventional portable gas cooking stove. Fig. 2 is a front view of a gas cooking stove including the burner in accordance with the present invention. Fig. 3 is a top plan view of the gas cooking stove illustrated in Fig. 2. Fig. 4A is a top plan view of an igniter. Fig. 4B is a front view of the igniter illustrated in Fig. 4A. Fig. 4C is a side view of the igniter illustrated in Fig. 4A. Fig. 5A is a top plan view of an igniter cover. Fig. 5B is a side view of the igniter cover illustrated in Fig. 5A. Fig. 6 is a plan view of an igniter support. Fig. 7A is a top plan view of a generator. Fig. 7B is a front view of the generator illustrated in Fig. 7A. Fig. 7C is a side view of the generator illustrated in Fig. 7A. Figs. 2 and 3 illustrate a gas cooking stove including the burner in accordance with a preferred embodiment. As illustrated in Figs. 2 and 3, the gas cooking stove is comprised of a gas cartridge 20 (illustrated only in Fig. 3) filled with pressurized combustible gas, a gas burner 21 to which combustible gas is supplied from the gas cartridge 20 and which burns the combustible gas, a plug fitting 22 adjusting a flow of the combustible gas supplied from the gas cartridge 20, and a gas tube 23 through which the combustible gas is supplied from the gas cartridge 20 to the gas burner 21. The gas burner 21 is comprised of a joint block 24 to which the gas tube 23 is connected, a burner head 25 having a number of openings 25a at a surface thereof, a saucer-shaped windshield 25b surrounding the burner head 25, a mixing tube 26 connecting the joint block 24 to the burner head 25, kettle holders 27 connected to the mixing tube 26, and an igniter 28 igniting mixture gas of air and the combustible gas, discharged from the burner head 25 through the openings 25a. Each of the kettle holders 27 is wound at one end thereof around the mixing tube 26, and is designed to be swingable in directions indicated with arrows A in Fig. 3. Figs. 4A to 4C illustrate a structure of the igniter 28. The igniter 28 is comprised of a base block 28a in the form of a square pole, a cylindrical pillar 28b upwardly extending from the base block 28a, an igniter section 28c upwardly extending from an upper end of the pillar 28b and generating spark, and a switch 28d activating the igniter 28 when pushed relative to the base block 28a. The igniter 28 is accommodated in an igniter cover 29 illustrated in Figs. 5A and 5B. The igniter cover 29 is comprised of a first cover portion 29a and a second cover portion 29b. The first cover portion 29a is open at a bottom thereof. The base block 28a of the igniter 28 is accommodated in the first cover portion 29a. As illustrated in Fig. 5A, the first cover portion 29a is formed at an upper surface thereof with a projecting portion 29c. The projecting portion 29c is formed with a circular opening 29d. The igniter cover 29 is fixed relative to the mixing tube 26 by inserting the mixing tube 26 into the circular opening 29d. The first cover portion 29a is formed at an upper surface at an end through which the switch 28d is inserted, with an inclined portion 29e obliquely, upwardly and outwardly inclining. Hence, the switch 28d can be readily pushed. The pillar 28b of the igniter 28 is accommodated in the second cover portion 29b. The second cover portion 29b has a rectangular cross-section, and is open at a side. As illustrated in Fig. 5A, the second cover portion 29b is formed at upper ends thereof with hookers 29f formed by inwardly bending walls of the second cover portion 29b. The second cover portion 29b is formed with vertically arranged oval openings 29g for diffusing heat from the igniter 28. The igniter cover 29 can be formed by, for instance, separately fabricating the first cover portion 29a and the second cover portion 29b, and welding them to each other. Fig. 6 is a plan view of an igniter support 30 which supports the igniter 28 at an upper end thereof. The igniter support 30 is comprised of a ring 30a and a rectangular portion 30b outwardly projecting from the ring 30a. The ring 30a is designed to have such an inner diameter that the ring 30a can be inserted into the mixing tube 26 just below the burner head 25. The rectangular portion 30b is designed to have the same size as a rectangular cross-section of the second cover portion 29b. Hence, the rectangular portion 30b can be inserted into the second cover portion 29b. The rectangular portion 30b is formed centrally with a circular opening 30c. The circular opening 30c is designed to have a diameter equal to a diameter of the pillar 28b of the igniter 28. Accordingly, the pillar 28b can be fit into the circular opening 30c of the rectangular portion 30b. When the igniter 28 is to be accommodated in the igniter cover 29, the ring 30a is inserted into the mixing tube 26 and the rectangular portion 30b is inserted into the second cover portion 29b. Then, the igniter 28 is positioned below the igniter cover 28, and then, is upwardly inserted into the igniter cover 29. Thus, the base block 28a is accommodated in the first cover portion 29a, and the pillar 28b is accommodated in the second cover portion 29b. Then, as illustrated in Fig. 3, pillar 28b is inserted in the vicinity of an upper end thereof into the circular opening 30c of the igniter support 30. Thus, the opening 29d formed in the projecting portion 29c is fit into the mixing tube to thereby ensure that the igniter 28 is fixed at a lower end thereof relative to the gas burner 21 and hence the mixing tube 26, and the opening 30c formed in the rectangular portion 30b is fit into the pillar 28b of the igniter 28 to thereby ensure that the igniter 28 is fixed at an upper end thereof relative to the gas burner 21 and hence the mixing tube 26. Figs. 7A to 7C illustrates a generator 31. The generator 31 is comprised of a hollow, reverse-U shaped pipe, and is connected at a free end thereof to the joint block 24. The combustible gas having been supplied from the gas cartridge 20 through the plug fitting 22 and the gas tube 23 passes through the joint block 24, and then, through the generator 31, and returns to the joint block 24. Thereafter, the combustible gas is supplied to the mixing tube 26 from the joint block 24. As illustrated in Figs. 2 and 3, the windshield 25b is formed with a cutout 25c. The generator 31 is positioned close to the burner head 25 in the cutout 25c. The generator 31 is designed to have such a height that a summit of the generator 31 is either almost level with or slightly higher than a summit of the burner head 25. When viewed from the burner head 25, the igniter 28 is located slightly outside the generator 31. When viewed horizontally, the igniter 28 is all surrounded in the generator 31. As illustrated in Fig. 2, the burner head 25 is formed at a surface thereof with a flame hole 32 as well as the openings 25a. The flame hole 32 has a greater size than a size of the opening 25a. A mesh sheet is arranged all over the flame hole 32. The igniter 28 is positioned such that the igniter section 28c faces the flame hole 32. In this embodiment, the igniter section 28c is slightly inclined towards the flame hole 32. The gas cooking stove in the instant embodiment is used as follows. The combustible gas under pressure is adjusted in a flow rate in the plug fitting 22, and then, is supplied to the joint block 24 through the gas tube 23. Then, the combustible gas is supplied to the generator 23 from the joint block 24. Since the generator 31 is positioned close to the burner head 25 as mentioned earlier, the generator 31 is heated by burning combustible gas blowing out from the burner head 25. Accordingly, the mixture gas passing through the generator 31 is also heated, and then, supplied to the mixing tube 26. The mixing tube 26 is formed at a surface thereof with a plurality of the openings 26a. External air is absorbed into the mixing tube 26 through the openings 26a by virtue of negative pressure generated when the combustible gas passes the mixing tube 26. Thus, the combustible gas is mixed with air into mixture gas of air and combustible gas. After entering the burner head 25, the mixture gas blows out through the openings 25a, and is ignited by the igniter 28 located in the vicinity of the burner head 25. The thus ignited mixture gas is burnt, and as a result, flame blows out through the openings 25a. The flame heats cooking appliances and/or food (not illustrated) put on the kettle holders 27. In the instant embodiment, the igniter section 28c is positioned perpendicular to a flow of the mixture gas discharged through the openings 25a. Hence, spark generated by the igniter section 28c flies perpendicularly to a flow of the mixture gas. In the conventional burner illustrated in Fig. 1, spark generated by the igniter 19 flies in parallel with a flow of the mixture gas. Hence, a contact area of spark with the mixture gas was relatively small. In contrast, spark flies perpendicularly to a flow of mixture gas in the instant embodiment. As a result, a contact area of spark with the mixture gas is greater than the same in the conventional burner. Hence, even if the mixture gas had a great velocity, it would be possible to stably ignite the mixture gas. The mixture gas of combustible gas and air at higher temperature is more likely to be ignited. Thus, the mixture gas which has been heated during passing through the generator 31 can be readily ignited by spark generated by the igniter 28.

Claims: A burner for a portable gas cooking stove, comprising: (a) a mixture gas pipe (26) having an open end through which a mixture gas of combustible gas and air is exhausted; (b) a burner head (25) connected to the mixture gas pipe (26) in a hermetically sealed condition and having at least one opening (25a, 32) at a surface thereof, the mixture gas blowing out through the opening (25a, 32); (c) a generator (31) comprised of a pipe through which the combustible gas flows, the generator (31) being arranged outside and close to the burner head (25); and characterized by an igniter (28) being located slightly outside the generator (31), wherein the igniter (28) generates a spark between the igniter (28) and the generator (31) in a range of 70°-110° to a flow of the mixture gas blowing out through a flame hole (32) of the burner head (25). The burner as set forth in claim 1, wherein the igniter (28) is supported at lower and upper ends thereof by the mixture gas pipe (26). The burner as set forth in claim 2, further comprising an igniter cover (29) in which the igniter (28) is accommodated, the igniter cover (29) having a projecting portion (29c) projecting in a direction, the projecting portion (29c) being formed with an opening (29d) having a diameter almost equal to a diameter of the mixture gas pipe (26), the igniter cover (29) being fixed relative to the mixture gas pipe (26) by engaging the projecting portion (29c) to the mixture gas pipe (26). The burner as set forth in claim 3, wherein the igniter (28) is comprised of: (a) a base block (28a) extending in a first direction; (b) a pillar (28b) extending in a second direction perpendicular to the first direction; (c) an igniter section (28c) extending from a summit of the pillar (28b); and (d) a switch (28d) movable in the first direction, and especially wherein the igniter cover (29) is comprised of (a) a first cover portion (29a) covering the base block (28a) therewith; and/or (b) a second cover portion (29b) covering the pillar (28b) therewith. The burner as set forth in claim 4, wherein the first cover portion (29a) has a portion (29e) located above the switch (28d) and bent upwardly and obliquely. The burner as set forth in claim 4, wherein the igniter (28) is supported by the mixture gas pipe (26) through an igniter support (30), the igniter support (30) being comprised of a ring (30a) engageable to the mixture gas pipe (26) and a projection (30b) fittable into the second cover portion (29b) of the igniter cover (29), the projection (30b) being formed with an opening (30c) into which the pillar (28b) is to be fit. The burner according to any of claims 1 to 6 wherein the igniter (28) generates spark between the burner head (25) and the generator (31). The burner according to any of claims 1 to 7, wherein the generator (31) is reverse U-shaped, and wherein the igniter (28) is positioned surrounded by the generator (31)when viewed from a front of the generator (31). The burner according to any of the preceding claims, wherein the igniter (28) generates spark in a direction perpendicular to a flow of the mixture gas blowing out through an opening (25a) of the burner head.

Inventors: YOKOYAMA HIROAKI, YOKOYAMA, HIROAKI
Applicants: SNOW PEAK INC, SNOW PEAK, INC.
Application year: 2000
Main classification: F24C3
IPC codes: F23Q3, F24C3