Concentric burner and gas stove

Abstract

To sufficiently suck primary air even when length of a slave burner inflow pipe is short, in a concentric burner comprising a slave burner 4 and a master burner 5 surrounding it, in which a slave burner inflow pipe 45 and a slave burner nozzle 46 faced at its upstream end are arranged on a stove top plate 2, and a tip of the slave burner nozzle is positioned on a lower side than the master burner 5 and on an inner radial side than the master burner when seen from above.SOLUTION: A slave burner body 41 has an extension part 413 extending on a lower side than a slave burner distribution chamber 43. An inner gap 414 communicated with the slave burner distribution chamber 43 is provided in a predetermined range in a peripheral direction of the extension part 413. A central peripheral portion of the inner gap 414 is formed at a narrow portion 4141, at which radial width thereof is narrower than radial width of the other portion of the inner gap. A slave burner inflow pipe 45 is arranged, so that a downstream end is communicated with the narrow portion 4141 of the inner gap 414 and the pipe extends outward in a radial direction along a radial line passing through a peripheral center of the narrow portion.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a parent-child burner provided on a gas stove and a gas stove equipped with this parent-child burner. [Background technology]

[0002] Conventionally, this type of parent-child burner is known from the one described in Patent Document 1. In this type, the child burner includes a child burner body exposed on the top plate of the gas stove, a child burner cap with multiple child burner flame holes formed therein for ejecting the mixture in the child burner distribution chamber, which is placed on the child burner body so as to define a child burner distribution chamber between the child burner body and the child burner cap, and a child burner inlet pipe extending horizontally from the child burner body on the top plate of the gas stove, and the mixture of fuel gas and primary air ejected from the nozzle hole at the tip of the child burner nozzle provided facing the opening at the upstream end of the child burner inlet pipe is supplied to the child burner distribution chamber via the child burner inlet pipe. The parent burner also comprises an annular parent burner body surrounding the child burner body exposed on the top plate of the gas stove, an annular parent burner cap placed on the parent burner body so as to define a parent burner distribution chamber between the parent burner body and the parent burner cap, and having multiple parent burner flame holes formed therein for spraying the mixed gas in the parent burner distribution chamber, and a parent burner inlet pipe extending from the parent burner body below the top plate of the gas stove, so that the mixed gas of fuel gas and primary air sprayed from the nozzle hole at the tip of the parent burner nozzle provided facing the opening at the upstream end of the parent burner inlet pipe is supplied to the parent burner distribution chamber via the parent burner inlet pipe.

[0003] In general parent-child burners, the child burner inlet pipe extends below the top plate of the gas stove, just like the parent burner inlet pipe. However, this means that if the door of the cabinet with the gas stove built in on top is quickly opened when the parent-child burner is at its lowest flame (when only the child burner is burning at low flame), negative pressure will be created inside the cabinet, and this negative pressure will act on the opening at the upstream end of the child burner inlet pipe, causing the flame of the child burner to be drawn into the child burner distribution chamber, resulting in a misfire.

[0004] In contrast, in the device described in Patent Document 1, the child burner inlet pipe is arranged on the top plate of the gas stove, so even if the inside of the cabinet becomes negative pressure, this negative pressure does not act on the opening at the upstream end of the child burner inlet pipe, and the child burner does not misfire. However, when the child burner inlet pipe is arranged on the top plate of the gas stove, the child burner nozzle is also arranged on the top plate of the gas stove. And, since it would spoil the appearance if the child burner nozzle was conspicuous when viewed from above, in the device described in Patent Document 1, the tip of the child burner nozzle is positioned below the parent burner body and radially inward from the outer periphery of the parent burner body when viewed from above.

[0005] Here, in the parent-child burner described in Patent Document 1, the child burner inlet pipe is configured to have a venturi section near the upstream end. When fuel gas is ejected from the nozzle hole of the child burner nozzle, the negative pressure generated in the venturi section causes primary air to be sucked in from the opening at the upstream end of the child burner inlet pipe. In this case, in order to increase the amount of primary air sucked in, it is necessary to increase the length of the child burner inlet pipe. However, since the upstream end of the child burner inlet pipe needs to be positioned radially inward from the tip of the child burner nozzle, which is positioned radially inward from the outer periphery of the parent burner body, as viewed from above, the length of the child burner inlet pipe cannot be made as long as possible. As a result, it becomes impossible to set the maximum firepower of the child burner as large as possible in order to prevent a shortage of primary air.

[0006] In addition, when the length of the child burner inlet pipe is increased so that a shortage of primary air does not occur even if the maximum heat output of the child burner is set high, it is necessary to increase the outer diameter of the parent burner body so that the tip of the child burner nozzle is located radially inward from the outer periphery of the parent burner body when viewed from above. However, in this case, the flame of the parent burner hits the outer periphery of the bottom surface of the cooking vessel heated by the parent and child burners, reducing the thermal efficiency. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] CN212691761U Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above, the present invention has an object to provide a parent-child burner that can sufficiently draw in primary air even if the length of the child burner inlet pipe is short, and that allows the maximum firepower of the child burner to be set high without increasing the outer diameter of the parent burner body, as well as a gas stove equipped with this parent-child burner. [Means for solving the problem]

[0009] In order to solve the above problems, the first invention of the present application is a parent-child burner to be provided on a gas stove, which is composed of a child burner and a parent burner surrounding the child burner, the child burner is provided with a child burner body exposed on the top plate of the gas stove, a child burner cap with a plurality of child burner flame holes formed therein for ejecting the mixed gas in the child burner distribution chamber, which is placed on the child burner body so as to define a child burner distribution chamber between the child burner body and the child burner cap, and a child burner inlet pipe extending horizontally from the child burner body on the top plate of the gas stove, The nozzle hole at the tip of the child burner nozzle is provided facing the opening of the gas stove, and the mixture of fuel gas and primary air is supplied to the child burner distribution chamber through the child burner inlet pipe. The parent burner is made up of an annular parent burner body that surrounds the child burner body and is exposed on the top plate of the gas stove, an annular parent burner cap that is placed on the parent burner body so as to define a parent burner distribution chamber between the parent burner body and the parent burner cap and has multiple parent burner flame holes formed therein for ejecting the mixture in the parent burner distribution chamber, and a parent burner cap that extends from the parent burner body to below the top plate of the gas stove. and a parent burner inlet pipe, and a mixture of fuel gas and primary air ejected from a nozzle hole at the tip of a parent burner nozzle provided facing an opening at the upstream end of the parent burner inlet pipe is supplied to a parent burner distribution chamber via the parent burner inlet pipe, and the tip of the child burner nozzle is located below the parent burner body and radially inward from the outer periphery of the parent burner body when viewed from above, the child burner body has an extension portion extending below the child burner distribution chamber, and an internal gap communicating with the child burner distribution chamber is provided within a predetermined circumferential range of the extension portion, and the internal gap The circumferential central portion of the gap is formed into a narrow portion whose radial width is narrower than the radial width of other portions of the internal gap, and the downstream end of the sub-burner inlet pipe is connected to the narrow portion of the internal gap and is arranged to extend radially outward along a radial line passing through the circumferential center of this narrow portion, so that a mixture of fuel gas and primary air ejected from the nozzle hole of the sub-burner nozzle flows from the narrow portion of the internal gap to other portions of the internal gap through the sub-burner inlet pipe, thereby obtaining the effect of sucking in primary air from the opening at the upstream end of the sub-burner inlet pipe. A second aspect of the present invention is a gas stove comprising the parent-child burner of the first aspect of the present invention.

[0010] According to this invention (first invention), the primary air can be sufficiently sucked in even if the length of the child burner inlet pipe is short, due to the primary air suction effect obtained by the air-fuel mixture flowing from the narrow part of the internal gap provided in the extension part of the child burner body to the other part, which is the wide part of the internal gap. Therefore, even if the outer diameter of the parent burner body is not large, the tip of the child burner nozzle can be positioned radially inward from the outer periphery of the parent burner body when viewed from above, and the maximum heating power of the child burner can be set large without causing a shortage of primary air.

[0011] In the present invention, it is also preferable to provide a resistance imparting portion that increases the air flow resistance of the portion that communicates with the sub burner distribution chamber at the upper end of the narrow portion of the internal gap. This makes it possible to prevent the air-fuel mixture from drifting from the narrow portion of the internal gap to the sub burner distribution chamber directly above it, thereby preventing uneven distribution of heat in the circumferential direction of the sub burners.

[0012] In order to improve the suction effect of the primary air, it is necessary to make the radial width of the narrow portion of the internal gap considerably narrow. When the inner and outer peripheral wall surfaces of the internal gap are made of the same material and the internal gap is formed by casting, the radial width of the narrow portion cannot be made so narrow in order to ensure the strength of the casting mold. Therefore, in the present invention, it is desirable to make the inner and outer peripheral wall surfaces of the internal gap from different materials. This is advantageous in that the radial width of the narrow portion can be made sufficiently narrow.

[0013] In the present invention, it is also preferable that a visor portion extends radially inwardly from the inner periphery of the circumferential portion of the bottom wall of the parent burner body that matches the child burner nozzle to a position that covers at least the upstream end of the child burner inlet pipe from above, and that a hanging wall portion extending downward is provided on both circumferential sides of the visor portion. In this way, even if boil-over liquid falls between the parent burner body and the child burner body, the boil-over liquid can be prevented from getting on the nozzle hole of the child burner nozzle.

[0014] In addition, in the present invention, since the slave burner nozzle is disposed on the top plate of the gas stove, there is a possibility that overflow liquid will splash onto the nozzle hole at the tip of the slave burner nozzle, causing clogging of the nozzle hole. Here, if the tip of the slave burner nozzle is positioned directly below the master burner body, it is possible to prevent overflow liquid from splashing directly onto the nozzle hole of the slave burner nozzle. However, it is not possible to prevent overflow liquid from running down the underside of the bottom wall of the master burner body and splashing onto the nozzle hole of the slave burner nozzle. In this case, if a skirt portion extending downward is extended around the outer periphery of the bottom wall of the master burner body, it is possible to prevent overflow liquid from flowing around the outer periphery of the master burner body to the underside of the bottom wall, which helps to prevent clogging of the nozzle hole of the slave burner nozzle.

[0015] In the device described in Patent Document 1, the tip of the child burner nozzle is also located directly below the parent burner body, and a skirt portion extending downward is extended around the outer periphery of the bottom wall of the parent burner body. However, the height of the lower end of the skirt portion is higher than the nozzle hole of the child burner nozzle. Here, a relatively strong air current (air flow) is generated between the top plate of the gas stove and the parent burner during combustion of the child burner, which is drawn by the updraft generated by the combustion and heads toward the child burner. Therefore, if the height of the lower end of the skirt portion is higher than the nozzle hole of the child burner nozzle, there is a possibility that the splash of the boiled-over liquid dripping from the lower end of the skirt portion will ride on the air current generated between the top plate and the parent burner and land on the nozzle hole of the child burner nozzle. Therefore, it is desirable to set the height of the lower end of the skirt portion to be equal to or lower than the nozzle hole of the child burner nozzle. This can effectively prevent the splash of the boiled-over liquid dripping from the lower end of the skirt portion from riding on the air current generated between the top plate and the parent burner and landing on the nozzle hole of the child burner nozzle.

[0016] In the gas stove of the second invention of the present application, when the parent and child burners have the skirt portion, it is preferable to provide a raised portion that is raised upward in a portion of the top plate of the gas stove that is located radially inward from the skirt portion when viewed from above, compared to a portion of the top plate that is radially outward from the skirt portion, and to position the tip of the child burner nozzle radially inward from the contour of the raised portion when viewed from above. This prevents overflowing liquid that falls from the skirt portion from flowing onto the top plate near the tip of the child burner nozzle and getting into the nozzle hole. [Brief description of the drawings]

[0017] [Figure 1] 1 is a perspective view of a main part of a gas stove equipped with a parent and child burner according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional side view taken along line II-II in FIG. [Diagram 3] FIG. 3 is a cross-sectional plan view taken along line III-III in FIG. 2. [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 2. [Diagram 5] FIG. 2 is a perspective view of a parent and child burner according to the embodiment in an exploded state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 1 and 2 show a gas stove equipped with a parent-child burner A according to an embodiment of the present invention. The gas stove has a top plate 2 that covers the top surface of a stove body 1. The top plate 2 is composed of a top plate main body 21 and a cover plate 22 that prevents overflowing liquid from seeping in through a burner opening 21a that is opened in the top plate main body 21 and faces the parent-child burner A. A trivet 3 having a plurality of trivet claws 31 is placed on the top plate 2 so as to surround the burner opening 21a.

[0019] The parent-child burner A is composed of a child burner 4 and a parent burner 5 surrounding the child burner 4. The heat can be changed widely from a minimum heat where only the child burner 4 is burned at low heat to a maximum heat where both the child burner 4 and the parent burner 5 are burned at high heat. A thermocouple 6 for detecting the flame of the child burner 4 is attached to the child burner 4, and an ignition electrode 7 for igniting the parent burner 5 is attached to the parent burner 5.

[0020] The sub burner 4 includes a sub burner body 41 exposed on the top plate 2 of the gas stove, and a sub burner cap 42 placed on the sub burner body 41. Referring also to FIG. 5, the sub burner body 41 has an outer cylinder 411 and an inner cylinder 412 formed of separate members. The sub burner cap 42 has an outer cylinder portion 421 seated on the upper end of the outer cylinder 411 of the sub burner body 41, and an inner cylinder portion 422 fitted into the inner cylinder 412 of the sub burner body 41. An annular sub burner distribution chamber 43 is defined between the sub burner body 41 and the sub burner cap 42. A plurality of sub burner flame holes 44 for ejecting the mixture in the sub burner distribution chamber 43 are formed in the outer cylinder portion 421 of the sub burner cap 42.

[0021] The slave burner 4 further includes a slave burner inlet pipe 45 that extends horizontally from the slave burner body 41 on the top plate 2 of the gas stove. A slave burner nozzle 46 is provided on the top plate 2, facing an opening 451 at the upstream end of the slave burner inlet pipe 45. The slave burner nozzle 46 is attached to a nozzle holder 461 that is fixed to a mounting base 11 fixed to the stove body 1 so as to be exposed on the top plate 2 through the cover plate 22. Fuel gas is supplied to the slave burner nozzle 46 via a gas pipe 462 for the slave burner and the nozzle holder 461. A mixture of fuel gas and primary air ejected from a nozzle hole 46a at the tip of the slave burner nozzle 46 is supplied to the slave burner distribution chamber 43 via the slave burner inlet pipe 45.

[0022] The parent burner 5 includes an annular parent burner body 51 surrounding the child burner body 41 exposed on the top plate 2 of the gas stove, and an annular parent burner cap 52 placed on the parent burner body 51. Referring also to FIG. 5, the parent burner body 51 has an outer cylinder part 512 and an inner cylinder part 513 erected on the outer periphery and inner periphery of the annular bottom wall part 511. The parent burner cap 52 has an outer cylinder part 521 seated on the upper end of the outer cylinder part 512 of the parent burner body 51, and an inner cylinder part 522 fitted on the inner cylinder part 513 of the parent burner body 51. An annular parent burner distribution chamber 53 is defined between the parent burner body 51 and the parent burner cap 52. A plurality of parent burner flame holes 54 from which the mixed gas in the parent burner distribution chamber 53 is ejected are formed in the outer cylinder part 521 of the parent burner cap 52. In addition, on the upper surface of the parent burner cap 52, a slit-shaped flame transfer flame hole 54a extending in the radial direction is formed for flame transfer between the child burner 4 and the parent burner 5.

[0023] The parent burner 5 further includes a parent burner inlet pipe 55 extending from the parent burner body 51 below the top plate 2 of the gas stove. A mixture of fuel gas and primary air ejected from a nozzle hole at the tip of a parent burner nozzle (not shown) provided facing the opening at the upstream end of the parent burner inlet pipe 55 is supplied to the parent burner distribution chamber 53 through the parent burner inlet pipe 55. The parent burner inlet pipe 55 is composed of a downstream pipe 551 that fits into a port portion 53a that communicates with the parent burner distribution chamber 53 and extends to the bottom of the top plate 2, and an upstream pipe 552 that is connected to the lower end of the downstream pipe 551 via a connecting pipe portion 552a and extends horizontally below the top plate 2. A venturi portion 552b is formed in the upstream pipe 552 near its upstream end. When fuel gas is ejected from the nozzle hole of the parent burner nozzle, negative pressure is generated in the venturi portion 552b, causing primary air to be sucked in from the upstream end of the upstream pipe 552, i.e., the opening at the upstream end of the parent burner inlet pipe 55.

[0024] However, when the child burner nozzle 46 is arranged on the top plate 2 of the gas stove as in this embodiment, if the child burner nozzle 46 stands out when viewed from above, it will spoil the appearance. Therefore, the tip of the child burner nozzle 46 is positioned below the parent burner body 51 and radially inward from the outer periphery of the parent burner body 51 when viewed from above. Here, if the child burner inlet pipe 45 has a venturi section near the upstream end like the parent burner inlet pipe 55, it is necessary to increase the length of the child burner inlet pipe 45 in order to increase the amount of primary air suction. However, since the upstream end of the child burner inlet pipe 45 needs to be positioned radially inward from the tip of the child burner nozzle 46, the length of the child burner inlet pipe 45 cannot be made as long as possible. As a result, it becomes impossible to set the maximum firepower of the child burner 4 to a large value in order to prevent a shortage of primary air. Furthermore, when the length of the slave burner inlet pipe 45 is increased so that a shortage of primary air does not occur even when the maximum heating power of the slave burner 4 is set high, it is necessary to increase the outer diameter of the parent burner body 51 so that the tip of the slave burner nozzle 46 is located radially inward from the outer periphery of the parent burner body 51 when viewed from above. However, in this case, the flame of the parent burner 5 hits the outer periphery of the bottom surface of the cooking vessel above the trivet 3 heated by the parent and child burner A, reducing the thermal efficiency.

[0025] Therefore, in this embodiment, the sub burner body 41 has an extension 413 extending downward from the sub burner distribution chamber 43. Referring also to FIG. 3, an internal gap 414 communicating with the sub burner distribution chamber 43 is provided in a circumferentially predetermined range of the extension 413. The circumferential center portion of the internal gap 414 is formed as a narrow portion 4141 whose radial width is narrower than the radial width of the other portions of the internal gap 414, and the other portions of the internal gap 414, i.e., the circumferentially opposite sides, are formed as wide portions 4142 whose radial width is wider. The downstream end of the sub burner inlet pipe 45 communicates with the narrow portion 4141 of the internal gap 414, and is arranged to extend radially outward along a radial line passing through the circumferential center of the narrow portion 4141. The mixture of fuel gas and primary air sprayed from the nozzle hole 46a of the sub burner nozzle 46 flows from the narrow portion 4141 to the wide portion 4142 of the internal gap 414 via the sub burner inlet pipe 45, thereby obtaining the effect of sucking in primary air from the opening 451 at the upstream end of the sub burner inlet pipe 45 (an effect similar to the so-called radial venturi effect).

[0026] This allows sufficient primary air to be sucked in even if the length of the slave burner inlet pipe 45 is short. Therefore, even if the outer diameter of the parent burner body 51 is not increased, the tip of the slave burner nozzle 46 can be positioned radially inward from the outer periphery of the parent burner body 51 when viewed from above, and the maximum heating power of the slave burner 4 can be set large without causing a shortage of primary air.

[0027] In addition, in this embodiment, the outer cylinder 411 and the inner cylinder 412 of the sub burner body 41 are extended downward below the sub burner distribution chamber 43 to form an extension portion 413. The inner peripheral side wall surface 414a and the outer peripheral side wall surface 414b of the internal gap 414 are configured of the inner cylinder 412 and the outer cylinder 411, which are separate members. This makes it possible to sufficiently narrow the radial width of the narrow portion 4141 of the internal gap 414, unlike the case where the internal gap 414 is formed by casting out of the same member, and ensures the above-mentioned primary air suction effect.

[0028] In addition, a seal portion 412a is formed in the portion that becomes the extension portion 413 of the inner tube 412 of the sub burner body 41, located in a portion other than the internal gap 414, and contacts the inner peripheral surface of the portion that becomes the extension portion 413 of the outer tube 411 of the sub burner body 41. In addition, the portion that matches the narrow portion 4141 of the inner peripheral side wall surface 414a and the outer peripheral side wall surface 414b of the internal gap 414 is a plane perpendicular to a radial line passing through the circumferential center of the narrow portion 4141 of the internal gap 414. Furthermore, an opening 452 at the downstream end of the sub burner inlet pipe 45 is opened in the portion that matches the narrow portion 4141 of the outer peripheral side wall surface 414b of the internal gap 414. And the internal flow passage 453 that connects the opening 451 at the upstream end and the opening 452 at the downstream end of the sub burner inlet pipe 45 is narrowed toward the downstream side.

[0029] However, if the air-fuel mixture is biased from the narrow portion 4141 of the internal gap 414 to the portion of the sub burner distribution chamber 43 directly above it, the flame will become larger in the circumferential portion of the sub burner cap 42 that matches the narrow portion 4141, and the circumferential distribution of the firepower of the sub burners 4 will become non-uniform. Therefore, in this embodiment, a resistance imparting portion 415 is provided that increases the air flow resistance of the portion that communicates with the sub burner distribution chamber 43 at the upper end of the narrow portion 4141 of the internal gap 414. This prevents the air-fuel mixture from being biased from the narrow portion 4141 of the internal gap 414 to the portion of the sub burner distribution chamber 43 directly above it, and prevents the circumferential distribution of the firepower of the sub burners 4 from becoming non-uniform. In this embodiment, the resistance imparting portion 415 is configured as a protrusion protruding like an eave from the upper end of a portion that matches the narrow portion 4141 of the inner peripheral wall surface 414a of the internal gap 414, but it is also possible to configure the resistance imparting portion 415 as a protrusion protruding from the upper end of a portion that matches the narrow portion 4141 of the outer peripheral wall surface 414b of the internal gap 414.

[0030] Furthermore, when the sub burner nozzle 46 is placed on the top plate 2 of the gas stove as described above, overflowing liquid may get on the nozzle hole 46a at the tip of the sub burner nozzle 46, causing clogging of the nozzle hole 46a. Therefore, the tip of the sub burner nozzle 46 is positioned directly below the parent burner body 51, and a skirt portion 514 extending downward is extended on the outer periphery of the bottom wall portion 511 of the parent burner body 51. This makes it possible to prevent overflowing liquid from directly getting on the nozzle hole 46a of the sub burner nozzle 46. Furthermore, the skirt portion 514 can prevent overflowing liquid from flowing around the outer periphery of the parent burner body 51 to the underside of the bottom wall portion 511. Therefore, overflowing liquid can also be prevented from running down the bottom wall portion 511 of the parent burner body 51 and getting on the nozzle hole 46a of the sub burner nozzle 46.

[0031] Meanwhile, between the top plate 2 of the gas stove and the main burner 5, a relatively strong air current (air flow) is generated toward the main burner 4 by being attracted by the rising air current generated by the combustion during the combustion of the main burner 4. Therefore, if the height of the lower end of the skirt portion 514 is higher than the nozzle hole 46a of the main burner nozzle 46, there is a possibility that the splash of the boiled-over liquid dripping from the lower end of the skirt portion 514 will ride on the air current generated between the top plate 2 and the main burner 5 and hit the nozzle hole 46a of the main burner nozzle 46. Therefore, it is desirable to set the height of the lower end of the skirt portion 514 to be equal to or lower than the nozzle hole 46a of the main burner nozzle 46. This can effectively prevent the splash of the boiled-over liquid dripping from the lower end of the skirt portion 514 from riding on the air current generated between the top plate 2 and the main burner 5 and hitting the nozzle hole 46a of the main burner nozzle 46. In this embodiment, the height of the lower end of the skirt portion 514 is set to be equal to the nozzle hole 46a of the main burner nozzle 46.

[0032] In addition, in a portion located radially inward from the skirt portion 514 as viewed from above the gas stove top plate 2, i.e., in a portion of the cover plate 22 located radially inward from the skirt portion 514, a raised portion 221 is provided that is raised upward compared to a portion of the cover plate 22 radially outward from the portion. As shown in FIG. 3, the tip of the child burner nozzle 46 is positioned radially inward from the contour of the raised portion 221 as viewed from above. This prevents the overflowing liquid that has fallen from the skirt portion 514 from flowing on the cover plate 22 to the vicinity of the tip of the child burner nozzle 46 and getting on the nozzle hole 46a. In this embodiment, a protruding portion 221a that protrudes radially outward from the skirt portion 514 is provided in the circumferential portion of the raised portion 221 that matches the child burner nozzle 46. However, since the nozzle holder 461 is positioned so as to protrude upward from the protruding portion 221a, the boiled-over liquid that falls from the skirt portion 514 onto the protruding portion 221a does not flow to the vicinity of the tip of the sub burner nozzle 46 because the nozzle holder 461 acts as an obstacle.

[0033] In this embodiment, a visor portion 515 extends radially inward from the inner periphery of the circumferential portion of the bottom wall portion 511 of the parent burner body 51 that matches the child burner nozzle 46 to a position that covers at least the upstream end of the child burner inlet pipe 45 from above. On both circumferential sides of this visor portion 515, as shown in FIG. 4, downwardly extending hanging walls 515a, 515a are provided. This prevents the overflowed liquid from getting onto the nozzle hole 46a of the child burner nozzle 46 even if the overflowed liquid falls between the parent burner body 51 and the child burner body 41. In this embodiment, the visor portion 515 is protruded so as to cover almost the entire portion of the child burner inlet pipe 45 that protrudes from the extension portion 413 of the child burner body 41 from above.

[0034] 5, the outer cylinder 411 of the child burner body 41 is integrally molded with a base plate portion 416 that is integrated with the bottom wall portion of the child burner inlet pipe 45 and that protrudes outward from a circumferential location that matches the child burner inlet pipe 45 at the bottom of the portion that becomes the extension portion 413 and the opposite location. The nozzle holder 461 that mounts the child burner nozzle 46 and the end of the base plate portion 416 on the nozzle holder 461 side are fixed to a common mounting base 11, thereby ensuring the concentricity of the child burner nozzle 46 and the child burner inlet pipe 45. In addition, the portion of the base plate portion 416 that protrudes outward from the opposite location of the circumferential location that matches the child burner inlet pipe 45 is provided with a short cylinder portion 416a into which the downstream pipe 551 of the parent burner inlet pipe 55 is fitted.

[0035] Although the embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited thereto. For example, in the above embodiment, the sub-burner inlet pipe 45 is integrally molded with the outer cylinder 411 of the sub-burner body 41, but the sub-burner inlet pipe 45 separate from the outer cylinder 411 may be connected to the outer cylinder 411. Also, in the above embodiment, the top plate 2 of the gas stove is composed of the top plate main body 21 and the cover plate 22, but the top plate main body 21 and the cover plate 22 may be integrated. [Explanation of symbols]

[0036] A...parent and child burners, 2...top plate, 221...raised portion, 4...child burner, 41...child burner body, 413...extension portion, 414...internal gap, 4141...narrow portion, 4142...wide portion (other portion of internal gap), 415...resistance imparting portion, 42...child burner cap, 43...child burner distribution chamber, 44...child burner flame hole, 45...child burner inlet pipe, 451...opening at upstream end, 46...child burner nozzle, 46a...nozzle hole, 5...parent burner, 51...parent burner body, 511...bottom wall portion, 514...skirt portion, 515...eaves portion, 515a...hanging wall portion, 52...parent burner cap, 53...parent burner distribution chamber, 54...parent burner flame hole, 55...parent burner inlet pipe.

Claims

1. A parent-child burner provided on a gas stove, the parent burner including a child burner and a parent burner surrounding the child burner, The slave burner comprises a slave burner body exposed on the top plate of the gas stove, a slave burner cap with a plurality of slave burner flame holes formed therein for spraying the mixture in the slave burner distribution chamber, which is placed on the slave burner body so as to define a slave burner distribution chamber between the slave burner body and the slave burner cap, and a slave burner inlet pipe extending horizontally from the slave burner body on the top plate of the gas stove, so that the mixture of fuel gas and primary air sprayed from the nozzle hole at the tip of the slave burner nozzle provided facing the opening at the upstream end of the slave burner inlet pipe is supplied to the slave burner distribution chamber via the slave burner inlet pipe, The parent burner comprises an annular parent burner body that surrounds the child burner body exposed on the top plate of the gas stove, an annular parent burner cap that is placed on the parent burner body so as to define a parent burner distribution chamber between the parent burner body and the parent burner cap and that has a plurality of parent burner flame holes formed therein for ejecting the mixture in the parent burner distribution chamber, and a parent burner inlet pipe that extends from the parent burner body below the top plate of the gas stove, so that the mixture of fuel gas and primary air ejected from the nozzle hole at the tip of the parent burner nozzle provided facing the opening at the upstream end of the parent burner inlet pipe is supplied to the parent burner distribution chamber via the parent burner inlet pipe, The tip of the child burner nozzle is located below the parent burner body and radially inward from the outer periphery of the parent burner body when viewed from above. A parent-child burner characterized in that the child burner body has an extension portion extending downwardly beyond the child burner distribution chamber, and an internal gap communicating with the child burner distribution chamber is provided in a predetermined circumferential range of the extension portion, the circumferential central portion of the internal gap is formed in a narrow portion whose radial width is narrower than the radial width of other portions of the internal gap, the child burner inlet pipe has a downstream end communicating with the narrow portion of the internal gap and is arranged to extend radially outward along a radial line passing through the circumferential center of this narrow portion, and a mixture of fuel gas and primary air ejected from the nozzle hole of the child burner nozzle flows from the narrow portion of the internal gap through the child burner inlet pipe to other portions of the internal gap, thereby obtaining the effect of sucking in primary air from the opening at the upstream end of the child burner inlet pipe.

2. 2. The parent-child burner according to claim 1, further comprising a resistance imparting portion for increasing the air flow resistance of a portion of the upper end of the narrow portion of the internal space which communicates with the child burner distribution chamber.

3. 2. A parent-child burner according to claim 1, wherein an inner peripheral wall surface and an outer peripheral wall surface of the internal space are formed of different members.

4. A parent-child burner as described in claim 1, characterized in that a eave portion extends radially inwardly from the inner circumference of the circumferential portion of the bottom wall portion of the parent burner body that coincides with the child burner nozzle to a position covering at least the upstream end of the child burner inlet pipe from above, and a hanging wall portion extending downwardly is provided on both circumferential sides of this eave portion.

5. A parent-child burner as described in claim 1, wherein the tip of the child burner nozzle is located directly below the parent burner body, and a skirt portion extends downwardly around the outer periphery of the bottom wall portion of the parent burner body, and the height of the lower end of the skirt portion is equal to or lower than the nozzle hole of the child burner nozzle.

6. A gas stove comprising the parent and child burner according to any one of claims 1 to 4.

7. A gas stove equipped with a parent-child burner as described in claim 5, characterized in that a portion of the gas stove top plate located radially inward from the skirt portion when viewed from above has a raised portion that is raised upward compared to a portion of the top plate radially outward from said portion, and the tip of the child burner nozzle is located radially inward from the contour of the raised portion when viewed from above.

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