Concentric burner and gas cooking stove

Abstract

Provided is a concentric burner which is formed of a slave burner 4 and a master burner 5 surrounding the slave burner and in which a slave burner inflow pipe 45 and a slave burner nozzle 46 facing the upstream end of the slave burner inflow pipe are arranged on a cooking stove top plate 2, and the tip of the slave burner nozzle is positioned below the master burner 5 and further inward in the radial direction than the outer periphery of the master burner when viewed from above, said concentric burner making it possible to sufficiently suction primary air even if the length of a slave burner inflow pipe is short.　The slave burner body 41 has an extension part 413 extending below a slave burner distribution chamber 43. An internal gap 414 communicating with the slave burner distribution chamber 43 is provided in a predetermined range in the circumferential direction of the extension part 413. The circumferential center portion of the internal gap 414 is formed in a narrow portion 4141 in which the radial width is narrower than the radial width of the other portion of the internal gap. The downstream end of the slave burner inflow pipe 45 communicates with the narrow portion 4141 of the internal gap 414, and is arranged so as to extend radially outward along a radial line passing through the center in the circumferential direction of the narrow portion.

Description

Parent and child burners and gas stoves

[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.

[0002] A known parent-child burner of this type is described in Patent Document 1. In this burner, the child burner comprises 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 spraying the mixture in the child burner distribution chamber and 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 a child burner nozzle provided facing the opening at the upstream end of the child burner inlet pipe, and a mixture of fuel gas sprayed from a nozzle hole at the tip of the child burner nozzle provided facing the opening at the upstream end of the child burner inlet pipe and primary air sucked into 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 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 that has multiple parent burner flame holes formed therein that spray 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 a mixture of fuel gas sprayed from the nozzle hole at the tip of the parent burner nozzle that is provided facing the opening at the upstream end of the parent burner inlet pipe and primary air that is sucked into 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 a typical parent-child burner system, the child burner inlet pipe extends below the stove top, just like the parent burner inlet pipe. However, 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 heat (when only the child burner is burning at low heat), negative pressure will build up inside the cabinet, and this negative pressure will act on the opening at the upstream end of the child burner inlet pipe. This can cause the child burner flame to be drawn into the child burner distribution chamber, resulting in a fire going out.

[0004] In contrast, in the device described in Patent Document 1, the slave burner inlet pipe is located on the top plate of the gas stove, so even if negative pressure occurs inside the cabinet, this negative pressure does not act on the opening at the upstream end of the slave burner inlet pipe, and misfires of the slave burner do not occur. However, when the slave burner inlet pipe is located on the top plate of the gas stove, the slave burner nozzle is also located on the top plate of the gas stove. Furthermore, since it would be unsightly if the slave burner nozzle were to be noticeable when viewed from above, in the device described in Patent Document 1, the tip of the slave burner nozzle is located below the main burner body and radially inward from the outer periphery of the main burner body when viewed from above.

[0005] In the parent-child burner described in Patent Document 1, the child burner inlet pipe is configured to have a venturi section near its upstream end. When fuel gas is ejected from the nozzle hole of the child burner nozzle, negative pressure is generated in the venturi section, causing primary air to be drawn in through the opening at the upstream end of the child burner inlet pipe. In this case, increasing the amount of primary air drawn in requires increasing the length of the child burner inlet pipe. However, because the upstream end of the child burner inlet pipe must 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 when viewed from above, the length of the child burner inlet pipe cannot be made very long. As a result, the maximum heating power of the child burner cannot be set to a large value in order to avoid a shortage of primary air.

[0006] Furthermore, if the length of the slave burner inlet pipe is increased so that a shortage of primary air does not occur even when the maximum heating power of the slave burners is set high, it is necessary to increase the outer diameter of the master burner body so that the tip of the slave burner nozzle is positioned radially inward from the outer periphery of the master burner body when viewed from above. However, in this case, the flame of the master burner will hit the outer periphery of the bottom surface of the cooking vessel heated by the master burner, reducing thermal efficiency.

[0007] CN212691761U

[0008] In view of the above, the present invention aims 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 heating power 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.

[0009] In order to solve the above problems, the first invention of the present application is a parent-child burner 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 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, which is formed with a plurality of child burner flame holes for ejecting the mixture in the child burner distribution chamber, and a child burner inlet pipe extending horizontally from the child burner body on the top plate of the gas stove, and an opening at the upstream end of the child burner inlet pipe The primary burner is provided with a nozzle hole at the tip of the secondary burner nozzle facing the primary burner, and a mixture of fuel gas ejected from the nozzle hole at the tip of the secondary burner nozzle facing the primary burner and primary air sucked from the opening at the upstream end of the secondary burner inlet pipe is supplied to the secondary burner distribution chamber via the secondary burner inlet pipe. The primary burner is made up of an annular primary burner body that surrounds the secondary burner body and is exposed on the top plate of the gas stove, an annular primary burner cap that is placed on the parent burner body so as to define the parent burner distribution chamber between the parent burner body and the parent burner body and has a plurality of parent burner flame holes formed therein that eject the mixture in the parent burner distribution chamber, and a secondary burner that ejects the gas mixture from the parent burner body. The stove is provided with a parent burner inlet pipe extending below the top plate of the stove, and a mixture of fuel gas ejected from a nozzle hole at the tip of a parent burner nozzle provided facing the opening at the upstream end of the parent burner inlet pipe and primary air sucked from 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, 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, and the child burner body has an extension portion extending below the child burner distribution chamber, and the periphery of the extension portion The present invention is characterized in that an internal gap communicating with the sub-burner distribution chamber is provided within a predetermined range in the circumferential direction, a circumferential central portion of the internal gap is formed as a narrow portion whose radial width is narrower than the radial width of the other portions of the internal gap, the downstream ends of the sub-burner inlet pipes are communicated with the narrow portion of the internal gap and are arranged to extend radially outward along a radial line passing through the circumferential center of this narrow portion, and the air-fuel mixture flows from the narrow portion of the internal gap through the sub-burner inlet pipes to the other portions of the internal gap, thereby obtaining the effect of drawing primary air from the openings at the upstream ends of the sub-burner inlet pipes.

[0010] According to the present invention (first invention), the primary air can be sufficiently sucked in even if the length of the slave burner inlet pipe is short, due to the primary air suction effect obtained by the flow of the air-fuel mixture from the narrow portion of the internal gap provided in the extension part of the slave burner body to the other wide portion of the internal gap. Therefore, even without increasing the outer diameter of the master burner body, the tip of the slave burner nozzle can be positioned radially inward from the outer periphery of the master burner body when viewed from above, and the maximum heating power of the slave burner can be set large without causing a shortage of primary air.

[0011] In addition, in the present invention, it is desirable to provide a resistance imparting portion that increases the airflow resistance at the portion that communicates with the sub burner distribution chamber at the upper end of the narrow portion of the internal gap, thereby preventing the air-fuel mixture from drifting from the narrow portion of the internal gap to the sub burner distribution chamber directly above it, and preventing uneven circumferential heating power distribution of the sub burners.

[0012] In order to enhance the primary air suction effect, the radial width of the narrow portion of the internal gap must be significantly narrowed. 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 very narrow due to the need 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 addition, in the present invention, it is desirable that a visor portion extends radially inward from the inner periphery of the circumferential portion of the bottom wall of the parent burner body that coincides with the child burner nozzle to a position that covers at least the upstream end of the child burner inlet pipe from above, and that hanging walls extending downward are provided on both circumferential sides of this visor portion. This prevents boil-over liquid from getting into the nozzle holes of the child burner nozzles even if the boil-over liquid falls between the parent burner body and the child burner body.

[0014] Furthermore, in the present invention, because the sub-burner nozzle is positioned on the top plate of the gas stove, there is a possibility that boil-over liquid will splash onto the nozzle hole at the tip of the sub-burner nozzle, causing clogging. However, if the tip of the sub-burner nozzle is positioned directly below the main burner body, it is possible to prevent boil-over liquid from splashing directly onto the nozzle hole of the sub-burner nozzle. However, it is not possible to prevent boil-over liquid from running down the underside of the bottom wall of the main burner body and splashing onto the nozzle hole of the sub-burner nozzle. In this case, if a skirt portion extending downward from the outer periphery of the bottom wall of the main burner body is provided, it is possible to prevent boil-over liquid from flowing around the outer periphery of the main burner body to the underside of the bottom wall, which helps prevent clogging of the nozzle hole of the sub-burner nozzle.

[0015] In the stove described in Patent Document 1, the tip of the slave burner nozzle is located directly below the master burner body, and a skirt portion extends downward from the outer periphery of the bottom wall of the master burner body. However, the height of the lower end of the skirt portion is higher than the nozzle hole of the slave burner nozzle. Here, during combustion of the slave burner, a relatively strong air current (air flow) is generated between the top plate of the gas stove and the master burner, drawn by the updraft generated by the combustion toward the slave burner. Therefore, if the height of the lower end of the skirt portion is higher than the nozzle hole of the slave burner nozzle, splashes of boiled-over liquid dripping from the lower end of the skirt portion may be carried by the air current generated between the top plate and the master burner and fall onto the nozzle hole of the slave burner nozzle. Therefore, it is desirable to set the height of the lower end of the skirt portion equal to or lower than the nozzle hole of the slave burner nozzle. This effectively prevents splashes of boiled-over liquid dripping from the lower end of the skirt portion from being carried by the air current generated between the top plate and the master burner and falling onto the nozzle hole of the slave burner nozzle.

[0016] In the gas stove of the second invention, when the main and sub burners have the skirt portion, it is desirable to provide a raised portion at a portion of the top plate of the gas stove that is located radially inward of the skirt portion when viewed from above, which is raised higher than the portion of the top plate that is radially outward of the skirt portion, and to position the tip of the sub burner nozzle radially inward from the contour of the raised portion when viewed from above. This prevents overflowing liquid from dripping from the skirt portion onto the top plate near the tip of the sub burner nozzle and getting into the nozzle hole.

[0017] 1 is a perspective view of a main part of a gas stove equipped with a parent-child burner according to an embodiment of the present invention; FIG. 2 is a cross-sectional side view taken along line II-II in FIG. 1; FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2; FIG. 4 is a perspective view of an exploded state of the parent-child burner according to an embodiment of the present invention;

[0018] 1 and 2 show a gas stove equipped with a dual 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 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 main body 21 and overlooks the dual burner A. A trivet 3 with multiple trivet claws 31 is placed on the top plate 2, surrounding 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 heating power can be changed widely from the minimum heating power that burns only the child burner 4 at low heat to the maximum heating power that burns both the child burner 4 and the parent burner 5 at high heat. The child burner 4 is equipped with a thermocouple 6 for detecting the flame of the child burner 4, and the parent burner 5 is equipped with an ignition electrode 7 for igniting the parent burner 5.

[0020] The sub burner 4 comprises 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 Figure 5, the sub burner body 41 has an outer cylinder 411 and an inner cylinder 412 formed as 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. The outer cylinder portion 421 of the sub burner cap 42 has multiple sub burner flame holes 44 formed therein for ejecting the air-fuel mixture from the sub burner distribution chamber 43.

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

[0022] The parent burner 5 includes an annular parent burner body 51 that surrounds the child burner body 41 exposed on the top plate 2 of the gas stove, and an annular parent burner cap 52 that is placed on the parent burner body 51. Referring also to FIG. 5 , the parent burner body 51 has an outer cylindrical portion 512 and an inner cylindrical portion 513 that extend from the outer and inner peripheries of an annular bottom wall portion 511. The parent burner cap 52 has an outer cylindrical portion 521 that seats on the upper end of the outer cylindrical portion 512 of the parent burner body 51, and an inner cylindrical portion 522 that fits around the inner cylindrical portion 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. The outer cylindrical portion 521 of the parent burner cap 52 has a plurality of parent burner flame holes 54 through which the air-fuel mixture in the parent burner distribution chamber 53 is ejected. In addition, a slit-shaped flame transfer hole 54 a extending in the radial direction is formed on the upper surface of the main burner cap 52 for flame transfer between the sub burner 4 and the main 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 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 and primary air sucked from the opening at the upstream end of the parent burner inlet pipe 55 is supplied to the parent burner distribution chamber 53 via 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 is provided on the underside of the bottom wall portion 511 of the parent burner body 51 at one circumferential position, and extends below 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 near the upstream end of the upstream pipe 552. When fuel gas is ejected from the nozzle hole of the parent burner nozzle, negative pressure is generated in the venturi portion 552b, which causes primary air to be sucked in from the upstream end of the upstream pipe 552, i.e., from the opening at the upstream end of the parent burner inlet pipe 55.

[0024] However, when the sub burner nozzle 46 is arranged on the top plate 2 of the gas stove as in this embodiment, if the sub burner nozzle 46 is conspicuous when viewed from above, it will spoil the appearance. Therefore, the tip of the sub burner nozzle 46 is positioned below the main burner body 51 and radially inward from the outer periphery of the main burner body 51 when viewed from above. Here, if the sub burner inlet pipe 45 has a venturi section near its upstream end like the main burner inlet pipe 55, the length of the sub burner inlet pipe 45 needs to be increased to increase the amount of primary air suction. However, because the upstream end of the sub burner inlet pipe 45 needs to be positioned radially inward from the tip of the sub burner nozzle 46, the length of the sub burner inlet pipe 45 cannot be made very long. As a result, the maximum heating power of the sub burner 4 cannot be set very high to avoid a shortage of primary air. Furthermore, if the length of the slave burner inlet pipe 45 is increased so as not to cause a shortage of primary air even when the maximum heating power of the slave burner 4 is set high, it is necessary to increase the outer diameter of the master burner body 51 so that the tip of the slave burner nozzle 46 is positioned radially inward from the outer periphery of the master burner body 51 when viewed from above. However, in this case, the flame of the master burner 5 will hit the outer periphery of the bottom surface of the cooking vessel on the trivet 3 heated by the master burner A, reducing thermal efficiency.

[0025] Therefore, in this embodiment, the sub burner body 41 has an extension 413 that extends downward below the sub burner distribution chamber 43. Referring also to Figure 3, an internal gap 414 that communicates with the sub burner distribution chamber 43 is provided within a predetermined circumferential range of the extension 413. The circumferential central 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, while the other portions of the internal gap 414, i.e., the circumferential side portions, 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 the sub burner inlet pipe 45 is arranged to extend radially outward along a radial line passing through the circumferential center of this narrow portion 4141. The mixture flows from the narrow portion 4141 to the wide portion 4142 of the internal gap 414 through the sub-burner inlet pipe 45, thereby achieving the effect of drawing 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 drawn in even if the length of the slave burner inlet pipe 45 is short. Therefore, even without increasing the outer diameter of the master burner body 51, the tip of the slave burner nozzle 46 can be positioned radially inward from the outer periphery of the master 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 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 wall surface 414a and the outer peripheral wall surface 414b of the internal gap 414 are formed of separate members, the inner cylinder 412 and the outer cylinder 411. This makes it possible to sufficiently narrow the radial width of the narrow portion 4141 of the internal gap 414, unlike when the internal gap 414 is formed by casting out of the same member, and reliably obtain the primary air suction effect described above.

[0028] In addition, a seal portion 412a is formed in the extension 413 of the inner cylinder 412 of the sub burner body 41, located outside the internal gap 414, and contacts the inner circumferential surface of the extension 413 of the outer cylinder 411 of the sub burner body 41. The portions of the inner and outer wall surfaces 414a and 414b of the internal gap 414 that coincide with the narrow portion 4141 form a plane perpendicular to a radial line passing through the circumferential center of the narrow portion 4141 of the internal gap 414. An opening 452 at the downstream end of the sub burner inlet pipe 45 is formed in the portion of the outer wall surface 414b of the internal gap 414 that coincides with the narrow portion 4141. An internal flow path 453 connecting the upstream opening 451 and the downstream opening 452 of the sub burner inlet pipe 45 tapers downstream.

[0029] Incidentally, if the air-fuel mixture drifts 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 coincides with the narrow portion 4141, causing the circumferential heating power distribution of the sub burners 4 to become non-uniform. Therefore, in this embodiment, a resistance imparting portion 415 is provided that increases the airflow resistance in 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 drifting from the narrow portion 4141 of the internal gap 414 to the portion of the sub burner distribution chamber 43 directly above it, preventing the circumferential heating power distribution of the sub burners 4 from becoming non-uniform. In this embodiment, the resistance imparting portion 415 is configured as a protrusion protruding like a canopy from the upper end of the portion that matches the narrow portion 4141 of the inner 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 the portion that matches the narrow portion 4141 of the outer 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 splash onto 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 main burner body 51, and a skirt portion 514 is provided that extends downward around the outer periphery of the bottom wall portion 511 of the main burner body 51. This prevents overflowing liquid from splashing directly onto the nozzle hole 46a of the sub burner nozzle 46. Furthermore, the skirt portion 514 prevents overflowing liquid from the outer periphery of the main burner body 51 onto the underside of the bottom wall portion 511. This also prevents overflowing liquid from running down the bottom wall portion 511 of the main burner body 51 and splashing onto the nozzle hole 46a of the sub burner nozzle 46.

[0031] During combustion of the sub-burners 4, a relatively strong air current (air flow) is generated between the top plate 2 and the main burner 5 of the gas stove, attracted by the updraft generated by the combustion and directed toward the sub-burners 4. Therefore, if the height of the lower end of the skirt portion 514 is higher than the nozzle hole 46a of the sub-burner nozzle 46, splashes of boiled-over liquid dripping from the lower end of the skirt portion 514 may be carried by the air current generated between the top plate 2 and the main burner 5 and fall onto the nozzle hole 46a of the sub-burner nozzle 46. For this reason, 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 sub-burner nozzle 46. This effectively prevents splashes of boiled-over liquid dripping from the lower end of the skirt portion 514 from being carried by the air current generated between the top plate 2 and the main burner 5 and falling onto the nozzle hole 46a of the sub-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 46 a of the sub-burner nozzle 46 .

[0032] Furthermore, a portion of the cover plate 22 located radially inward of the skirt portion 514 when viewed from above the stove top 2, i.e., a portion of the cover plate 22 located radially inward of the skirt portion 514, is provided with a raised portion 221 that is raised upward relative to the portion of the cover plate 22 located radially outward of the skirt portion 514. As shown in FIG. 3 , the tip of the sub-burner nozzle 46 is located radially inward of the contour of the raised portion 221 when viewed from above. This prevents overflowing liquid from the skirt portion 514 from flowing over the cover plate 22 to the vicinity of the tip of the sub-burner nozzle 46 and getting onto the nozzle hole 46a. In this embodiment, a protruding portion 221a that protrudes radially outward from the skirt portion 514 is provided at the circumferential portion of the raised portion 221 that coincides with the sub-burner nozzle 46. However, since the nozzle holder 461 is positioned so as to protrude upward from the protruding portion 221a, the boil-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 coincides with the child burner nozzle 46 to a position that covers at least the upstream end of the child burner inlet pipe 45 from above. As shown in FIG. 4 , downwardly extending hanging walls 515a, 515a are provided on both circumferential sides of this visor portion 515. This prevents overflow liquid from spilling onto the nozzle hole 46a of the child burner nozzle 46, even if the overflow liquid falls between the parent burner body 51 and the child burner body 41. In this embodiment, the visor portion 515 protrudes so as to cover from above almost the entire portion of the child burner inlet pipe 45 that protrudes from the extension portion 413 of the child burner body 41.

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

[0035] Although the embodiments of the present invention have 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 tube 411 of the sub-burner body 41, but a sub-burner inlet pipe 45 separate from the outer tube 411 may be connected to the outer tube 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 also be integrated.

[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 for use in a gas stove, comprising a child burner and a parent burner surrounding the child burner, the child burner comprising 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 spraying 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, such that a mixture of fuel gas sprayed 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 and primary air sucked in from 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 comprises an annular parent burner body surrounding a child burner body exposed on the top plate of the gas stove, an annular parent burner cap with a plurality of parent burner flame holes formed therein for ejecting the mixture in the parent burner distribution chamber, which 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 a parent burner inlet pipe extending from the parent burner body below the top plate of the gas stove, so that a mixture of fuel gas ejected from a nozzle hole at the tip of a parent burner nozzle provided facing the opening at the upstream end of the parent burner inlet pipe and primary air sucked in from 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, 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, 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, and 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, so that the mixed gas 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. A parent-child burner as claimed in claim 1, characterized in that a resistance imparting section is provided for increasing the air flow resistance of the portion communicating with the child burner distribution chamber at the upper end of the narrow portion of the internal gap.

3. A parent-child burner according to claim 1, characterized in that the inner peripheral wall surface and the outer peripheral wall surface of the internal gap are made of different materials.

4. A parent-child burner as described in claim 1, characterized in that a visor portion extends radially inwardly from the inner circumference of the circumferential portion of the bottom wall portion of the parent burner body that matches 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 visor 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 downward around the outer periphery of the bottom wall 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 a parent-child burner according to any one of claims 1 to 4.

7. A gas stove equipped with a parent and child burner as described in claim 5, characterized in that a portion of the top plate of the gas stove that is 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 that is 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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