Patent Abstract:
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 gas mixture 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 gas mixture blowing out through the opening, and (c) an igniter igniting the gas mixture blowing out through the opening of the burner head, the igniter generating a spark in a direction perpendicular to a flow of the gas mixture blowing out through the opening of the burner head. The burner makes it possible for the spark to make contact with the gas mixture flow in a larger contact area than that of a conventional burner. Accordingly, it is possible to stably ignite the gas mixture, even if the gas mixture has a great flow velocity.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     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. 
     2. Description of the Related Art 
     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  16 a 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  19   a.    
     The combustible gas is filled in the gas cartridge  11  in a pressurized condition. Hence, when the gas passage is opened 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  17   a  (only one of them is illustrated in FIG.  1 ). External air is absorbed into the mixing tube  17  through the openings  17   a  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  17   a , 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  16   a , and is ignited by the electric igniter  19  located in the vicinity of the burner head  16 . 
     The flame of the 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  16   a  of the burner head  16 . 
     If the gas mixture is discharged at a great rate, the gas mixture is rarely ignited by the spark generated by the igniter  19 , resulting in incomplete combustion of the gas mixture. 
     In addition, in the gas burner illustrated in FIG. 1, the igniter  19  is supported only by the support  19   a , resulting in that the igniter  19  cannot be stably fixed relative to a gas flow of the gas mixture discharged through the openings  16   a . This also causes incomplete combustion of the mixture gas. 
     SUMMARY OF THE INVENTION 
     In view of the above-mentioned problems in the conventional gas burners, it is an object of the present invention to provide a burner which is capable of stably igniting a gas mixture discharged from a burner head, and is capable also of stably supporting an igniter to thereby ensure ignition of the gas mixture. 
     There is provided a burner to be used for a portable gas cooking stove, including (a) a gas mixture 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 gas mixture blowing out through the opening, and (c) an igniter igniting the gas mixture blowing out through the opening of the burner head, the igniter generating a spark in a direction perpendicular to a flow of the gas mixture 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 gas mixture discharged through the openings  16   a  of the burner head  16 . Thus, a contact area between the spark and the gas mixture flow is relatively small. As a result, if the gas mixture had a great velocity, it was difficult to ignite the gas mixture 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 gas mixture discharged through openings of a burner head. As a result, the spark is generated in a direction perpendicularly to a flow of gas mixture. Hence, a contact area between the spark and a flow of gas mixture 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 a gas mixture, even if the gas mixture 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. 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 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 an 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. 
     There is further provided a burner to be used for a portable gas cooking stove, including (a) a gas mixture pipe having an open end through which a gas mixture 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 gas mixture blowing out through the opening, (c) an igniter igniting the gas mixture blowing out through the opening of the burner head, the igniter generating a spark in a direction perpendicular to a flow of the gas mixture blowing out through the opening of the burner head, and (d) a generator comprised of a pipe through which the combustible gas flows, the generator being arranged outside and close to the burner head. 
     The burner includes the generator. 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 the gas mixture while passing through the mixture gas pipe. Since the generator is located close to the burner head, the generator is heated by burning the gas mixture blowing out of the burner head. Accordingly, the gas mixture passing through the generator is also heated, and is discharged from the burner head at a high temperature. 
     The gas mixture of combustible gas and air at a higher temperature is more likely to be ignited. Thus, the gas mixture which has been heated during passing through the generator can be readily ignited by the spark generated by the igniter. 
     It is preferable that the igniter generates the 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 the 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 gas mixture discharged through the openings of the burner head can be stabilized, ensuring stable ignition of the gas mixture. 
     The above and other objects 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. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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.  4 A. 
     FIG. 4C is a side view of the igniter illustrated in FIG.  4 A. 
     FIG. 5A is a top plan view of an igniter cover. 
     FIG. 5B is a side view of the igniter cover illustrated in FIG.  5 A. 
     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.  7 A. 
     FIG. 7C is a side view of the generator illustrated in FIG.  7 A. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     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  25   a  at a surface thereof, a saucer-shaped windshield  25   b  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 the gas mixture of air and the combustible gas, discharged from the burner head  25  through the openings  25   a.    
     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  4 C illustrate a structure of the igniter  28 . The igniter  28  is comprised of a base block  28   a  in the form of a square pole, a cylindrical pillar  28   b  upwardly extending from the base block  28   a , an igniter section  28   c  upwardly extending from an upper end of the pillar  28   b  and generating a spark, and a switch  28   d  activating the igniter  28  when pushed relative to the base block  28   a.    
     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  29   a  and a second cover portion  29   b.    
     The first cover portion  29   a  is open at a bottom thereof. The base block  28   a  of the igniter  28  is accommodated in the first cover portion  29   a.    
     As illustrated in FIG. 5A, the first cover portion  29   a  is formed at an upper surface thereof with a projecting portion  29   c . The projecting portion  29   c  is formed with a circular opening  29   d . The igniter cover  29  is fixed relative to the mixing tube  26  by inserting the mixing tube  26  into the circular opening  29   d.    
     The first cover portion  29   a  is formed at an upper surface at an end through which the switch  28   d  is inserted, with an inclined portion  29   e  obliquely, upwardly and outwardly inclining. Hence, the switch  28   d  can be readily pushed. 
     The pillar  28   b  of the igniter  28  is accommodated in the second cover portion  29   b . The second cover portion  29   b  has a rectangular cross-section, and is open at a side. As illustrated in FIG. 5A, the second cover portion  29   b  is formed at upper ends thereof with hookers  29   f  formed by inwardly bending walls of the second cover portion  29   b.    
     The second cover portion  29   b  is formed with vertically arranged oval openings  29   g  for diffusing heat from the igniter  28 . 
     The igniter cover  29  can be formed by, for instance, separately fabricating the first cover portion  29   a  and the second cover portion  29   b , 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  30   a  and a rectangular portion  30   b  outwardly projecting from the ring  30   a.    
     The ring  30   a  is designed to have such an inner diameter that the ring  30   a  can be engaged to the mixing tube  26  just below the burner head  25 . 
     The rectangular portion  30   b  is designed to have the same size as a rectangular cross-section of the second cover portion  29   b . Hence, the rectangular portion  30   b  can be inserted into the second cover portion  29   b.    
     The rectangular portion  30   b  is formed centrally with a circular opening  30   c . The circular opening  30   c  is designed to have a diameter equal to a diameter of the pillar  28   b  of the igniter  28 . Accordingly, the pillar  28   b  can be fit into the circular opening  30   c  of the rectangular portion  30   b.    
     When the igniter  28  is to be accommodated in the igniter cover  29 , the ring  30   a  is engaged to the mixing tube  26  and the rectangular portion  30   b  is inserted into the second cover portion  29   b . 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  28   a  is accommodated in the first cover portion  29   a , and the pillar  28   b  is accommodated in the second cover portion  29   b.    
     Then, as illustrated in FIG. 3, pillar  28   b  is inserted in the vicinity of an upper end thereof into the circular opening  30   c  of the igniter support  30 . 
     Thus, the opening  29   d  formed in the projecting portion  29   c  is fit around 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  30   c  formed in the rectangular portion  30   b  is fit into the pillar  28   b  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  7 C 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  25   b  is formed with a cutout  25   c . The generator  31  is positioned close to the burner head  25  in the cutout  25   c . 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 completely surrounded by 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  25   a . The flame hole  32  has a greater size than a size of the opening  25   a . A mesh sheet is arranged all over the flame hole  32 . The igniter  28  is positioned such that the igniter section  28   c  faces the flame hole  32 . In this embodiment, the igniter section  28   c  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  31  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 gas mixture 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 openings  26   a . External air is absorbed into the mixing tube  26  through the openings  26   a  by virtue of negative pressure generated when the combustible gas passes the mixing tube  26 . Thus, the combustible gas is mixed with air into a gas mixture of air and combustible gas. 
     After entering the burner head  25 , the gas mixture blows out through the openings  25   a , and is ignited by the igniter  28  located in the vicinity of the burner head  25 . The thus ignited gas mixture is burnt, and as a result, flame blows out through the openings  25   a.    
     The flame heats cooking appliances and/or food (not illustrated) put on the kettle holders  27 . 
     In the instant embodiment, the igniter section  28   c  is positioned perpendicular to a flow of the gas mixture discharged through the openings  25   a . Hence, the spark generated by the igniter section  28   c  flies perpendicularly to a flow of the gas mixture. 
     In the conventional burner illustrated in FIG. 1, the spark generated by the igniter  19  flies in parallel with a flow of the gas mixture. Hence, a contact area of the spark with the gas mixture was relatively small. 
     In contrast, the spark flies perpendicularly to a flow of gas mixture in the instant embodiment. As a result, a contact area of the spark with the gas mixture is greater than the same in the conventional burner. Hence, even if the gas mixture had a great velocity, it would be possible to stably ignite the gas mixture. 
     The gas mixture of combustible gas and air at higher temperature is more likely to be ignited. Thus, the gas mixture which has been heated during passing through the generator  31  can be readily ignited by the spark generated by the igniter  28 . 
     While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the subject matter encompassed by way of the present invention is not to be limited to those specific embodiments. On the contrary, it is intended for the subject matter of the invention to include all alternatives, modifications and equivalents as can be included within the spirit and scope of the following claims. 
     The entire disclosure of Japanese Patent Application No. 11-2872 filed on Jan. 8, 1999 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.

Technology Classification (CPC): 5