Gas burner and heating cooker mounted with gas burner

Abstract

To stabilize detection of a flame by flame detection means of a gas burner.SOLUTION: A burner head 13 is placed on a burner body 11, and a plurality of burner ports 14 are defined by a plurality of radial burner port grooves 13d recessed on a lower end surface of a cylindrical wall 13a of the burner head and a placement surface 11d of the burner body. A pair of predetermined burner port grooves adjacent to each other out of the plurality of burner port grooves are defined as detection burner port grooves 21. A gas burner includes: a main partition wall part 22 sandwiched between the pair of detection burner port grooves; a pair of auxiliary partition wall parts 23 located adjacent to sides opposite to the main partition wall part of the pair of detection burner port grooves; and an eaves part 24 projecting from an upper end part of the cylindrical wall to a radial outer side. Flame detection means 16 is disposed on an outer peripheral surface of the main partition wall part in an opposing manner. The gas burner also includes: a first projection part 25 provided to project from an upper part on the outer peripheral surface of the main partition wall part to the radial outer side relative to an outer peripheral surface of the auxiliary partition wall part and directly connected to a lower surface of the eaves part; and a pair of second projection parts 26 each located on the radial outer aide corresponding to each of the pair of auxiliary partition wall parts and suspended from the lower surface of the eaves part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a gas burner capable of detecting a flame formed by combustion of a mixed gas of fuel gas and air with a flame detection means, and a cooking appliance equipped with the gas burner. [Background technology]

[0002] Gas burners that burn a mixture of fuel gas and air are widely used in cooking appliances such as gas stoves. A common type of burner includes a burner body with an annular mixing chamber to which the mixture gas is supplied and a burner head mounted on the burner body and covering the upper opening of the mixing chamber. The burner head has a cylindrical wall extending downward from its outer periphery. The lower end surface of the cylindrical wall has a plurality of radially extending flame grooves spaced circumferentially. The burner body has an annular mounting surface around the upper opening of the mixing chamber. When the burner head is mounted on the burner body, the lower end surface of the cylindrical wall abuts against the mounting surface, and the flame grooves and the mounting surface define a plurality of flame ports that communicate with the mixing chamber and open to the outer circumferential surface of the cylindrical wall. The mixed gas supplied to the mixing chamber is ejected from the flame ports. When ignited, the mixed gas begins to burn, forming a flame outside the flame ports.

[0003] Furthermore, gas burners often include a flame detection means such as a thermocouple for detecting a flame (ignition), and one known type of gas burner uses a predetermined pair of adjacent flame grooves among a plurality of flame grooves as detection flame grooves, and a thermocouple is disposed opposite the outer circumferential surface of the portion of the cylindrical wall sandwiched between the pair of detection flame grooves (main partition wall portion).When a flame is formed outside the pair of detection flame grooves defined by the pair of detection flame grooves and the mounting surface and strikes the thermocouple, a thermoelectromotive force is generated, and the flame is detected based on the thermoelectromotive force, and if no flame is detected, the supply of fuel gas is shut off.

[0004] In such gas burners, when the heat output increases, the flames from the pair of detection flame ports may merge. This combined flame not only tends to cause poor combustion due to a lack of secondary air, but also tends to stretch out in search of secondary air, changing the way the flame strikes the thermocouple and making it difficult to detect. Therefore, it has been proposed to provide a protrusion on the upper outer surface of the main partition wall to prevent the flames from merging at the pair of detection flame ports and separate them into two flames (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-20705 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in general, with gas burners, as the ambient temperature rises due to long-term combustion, expanded air with a low oxygen concentration tends to be supplied as secondary air, and even if the flame formed outside the pair of detection flame ports is divided into two as described above, the two flames will tend to spread apart toward the outside of the circumferential direction of the cylindrical wall in search of the missing oxygen, causing the flames to move away from the thermocouple, making it difficult to detect the flames using the thermocouple.

[0007] The present invention has been made in response to the above-mentioned problems in the conventional technology, and aims to provide a technology that can stabilize flame detection by a flame detection means installed in a gas burner. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the gas burner of the present invention employs the following configuration: <First aspect> a burner body having an annular mixing chamber to which a mixture of fuel gas and air is supplied, and a burner head mounted on the burner body and covering an upper opening of the mixing chamber, wherein a plurality of radially transverse flame port grooves are recessed at intervals in the circumferential direction in the lower end surface of a cylindrical wall extending vertically downward from the outer edge portion of the burner head, and an annular mounting surface is provided around the upper opening of the mixing chamber on the burner body, and when the burner head is mounted on the burner body and the lower end surface of the cylindrical wall abuts against the mounting surface, a plurality of flame ports communicating with the mixing chamber and opening into the outer peripheral surface of the cylindrical wall are defined by the plurality of flame port grooves and the mounting surface, and flames formed by combustion of the mixture gas ejected from the flame ports can be detected by flame detection means; The burner head is a predetermined pair of adjacent detection flame grooves among the plurality of flame grooves; a main partition wall portion sandwiched between the pair of detection flame grooves in the cylindrical wall; a pair of sub-partition wall portions adjacent to the pair of detection flame grooves on the cylindrical wall opposite to the main partition wall portions; a visor portion extending radially outward from an upper end of the outer peripheral surface of the cylindrical wall and projecting upward at least above the detection flame groove, the main partition wall portion, and the sub-partition wall portion; Equipped with the flame detection means is disposed opposite to the outer peripheral surface of the main partition wall portion, A first protrusion provided from an upper portion of the outer peripheral surface of the main partition wall portion to the outside in the radial direction of the burner head and protruding beyond the outer peripheral surface of the sub-partition wall portion is directly connected to the lower surface of the eave portion, A pair of second protrusions are provided vertically from the underside of the eave portion and are located radially outward of the burner head in correspondence with each of the pair of sub-partition wall portions. It is characterized by:

[0009] In the gas burner of the first aspect, a first convex portion is provided on the upper portion of the outer peripheral surface of the main partition wall portion located between a pair of detection flame ports defined by the pair of detection flame port grooves and the mounting surface. This prevents the flames in the pair of detection flame ports from joining together during high-power combustion, thereby dividing the leading edge (upper portion) of the flame into two. Furthermore, as the ejected mixed gas flows along the underside of the eaves portion at the upper portion of each of the pair of detection flame ports, it is sandwiched between the first convex portion and the second convex portion, thereby improving the linearity of the ejected mixed gas toward the radially outward direction of the burner head. By rectifying the ejected mixed gas in this manner, the two flames resulting from the combustion of the mixed gas can be prevented from spreading outward in the circumferential direction of the burner head, thereby maintaining an appropriate distance between the flame detection means and the flame, thereby stabilizing flame detection by the flame detection means.

[0010] <Second aspect> In the gas burner of the first aspect, The lower ends of the pair of second protrusions are located higher than the lower ends of the first protrusions. It is characterized by:

[0011] In this second aspect of the gas burner, the second convex portion is shorter than the first convex portion, so it is less likely to obstruct the intake of secondary air from the circumferential outside of the burner head, making it possible to prevent the flames in the pair of detection flame ports from extending radially outward from the burner head.

[0012] <Third aspect> In the gas burner of the first or second aspect, The outer end of the first protrusion in the radial direction of the burner head is located on approximately the same circumference as the outer end of the second protrusion or on the outer side in the radial direction. It is characterized by:

[0013] In this third aspect of the gas burner, even if the flames at the pair of detection flame ports extend radially outward from the burner head by the amount that not only the first convex portion but also a pair of second convex portions is added to the burner head, it is possible to maintain separation of the two flames by ensuring that the amount of radial outward protrusion of the first convex portion is equal to or greater than that of the second convex portions.

[0014] <Fourth aspect> In the gas burner of any one of the first to third aspects, The outer peripheral surface of the main partition wall portion is recessed radially inward of the burner head relative to the outer peripheral surface of the sub-partition wall portion. It is characterized by:

[0015] In the gas burner of this fourth aspect, the two flames at the bottom of the pair of detection flame ports can be promoted to merge when the flame is low in power, thereby improving flame stability, thereby making it possible to stabilize flame detection by the flame detection means.

[0016] <Fifth aspect> In the gas burner of any one of the first to fourth aspects, The width of the first protrusion in the circumferential direction of the burner head is approximately the same as the width of the main partition wall portion. It is characterized by:

[0017] In the gas burner of the fifth aspect, when the two flames combine at the bottom of the pair of detection flame ports, the combined flame is suppressed upward by the underside of the first convex portion, and therefore spreads radially outward from the burner head. In this way, the combined flame can be directed toward the flame detection means along the underside of the first convex portion, making it possible to stabilize flame detection by the flame detection means even when the flame is at a low power.

[0018] <Sixth aspect> In the gas burner of any one of the first to fifth aspects, the second protrusion is directly connected to the outer peripheral surface of the sub-partition wall portion, The distance between the first protrusion and the second protrusion in the circumferential direction of the burner head increases from the inside toward the outside in the radial direction of the burner head. It is characterized by:

[0019] In the gas burner of this sixth aspect, the flow rate of the mixed gas passing between the first convex portion and the second convex portion can be reduced, thereby preventing the flame caused by the combustion of the mixed gas from extending radially outward from the burner head, and making it possible to stabilize the detection of the flame by the flame detection means.

[0020] <Seventh aspect> In the gas burner of any one of the first to sixth aspects, inner circumferential surfaces of the main partition wall portion and the sub-partition wall portion are located radially inward of the burner head with respect to inner circumferential surfaces of other portions of the cylindrical wall excluding the main partition wall portion and the sub-partition wall portion, The detection flame groove has a parallel region on the outer periphery of the main partition wall portion where the distance between the main partition wall portion and the sub-partition wall portion is constant, and has a widened region on the inner periphery of the main partition wall portion where the distance between the main partition wall portion and the sub-partition wall portion widens toward the inside in the radial direction of the burner head. It is characterized by:

[0021] In the gas burner of the seventh aspect, the inner circumferential surfaces of the main partition wall portion and the sub-partition wall portion protrude radially inward of the burner head to extend the detection flame groove, and the widened region ensures smooth supply of the mixed gas from the mixing chamber to the detection flame groove, while the parallel region ensures that the mixed gas passing through the detection flame groove and ejected from the detection flame groove can be rectified, making it possible to stabilize the direction of the flame caused by combustion of the mixed gas at high heat output. As a result, the two flames in the pair of detection flame ports are prevented from spreading outward in the circumferential direction of the burner head, stabilizing flame detection by the thermocouple.

[0022] <Eighth aspect> The gas burner according to any one of the first to seventh aspects is mounted on a cooking appliance, and food to be cooked is heated by combustion in the gas burner.

[0023] In such a cooking appliance, the flame detection by the flame detection means of the gas burner installed therein can be stabilized, and therefore the safety of the cooking appliance can be improved. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a perspective view showing the external appearance of the upper part of a gas stove 1 as an example of a cooking appliance equipped with a gas burner 10 of the present embodiment. [Figure 2] 1 is a vertical cross-sectional view showing the internal structure of a gas burner 10 according to the present embodiment. [Figure 3] 1 is an enlarged cross-sectional view of a main flame port 14 and a flame holding port 15 defined by placing a cylindrical wall 13a of a burner head 13 on a mounting surface 11d of a burner body 11. FIG. [Figure 4] 1 is an explanatory diagram showing the configuration of a detection flame nozzle 20 in a gas burner 10 of the present embodiment. [Figure 5] 1 is an explanatory diagram showing flames formed outside a pair of detection flame ports 20 in the gas burner 10 of the present embodiment. FIG. [Figure 6] 10 is an explanatory diagram comparing the flames formed outside the pair of detection flame ports 20 in a case where there is no second protrusion 26 and a case where there is. FIG. [Figure 7] 1 is an explanatory diagram showing flames formed outside a pair of detection flame ports 20 when the gas burner 10 is at low flame power. FIG. [Figure 8] 1 is an explanatory diagram focusing on the inner peripheral sides of the main partition wall portion 22 and the sub-partition wall portion 23 in the gas burner 10 of the present embodiment. [Figure 9] 10 is a perspective view showing a second protrusion 26 of another example that hangs down from the underside of the eave portion 24 of the burner head 13 and is not directly connected to the sub-partition wall portion 23. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] FIG. 1 is a perspective view showing the upper appearance of a gas stove 1 as an example of a cooking appliance equipped with a gas burner 10 of this embodiment. The upper surface of the gas stove body (not shown) of the gas stove 1 is covered with a top plate 2, and the top of a gas burner 10 installed in the stove body protrudes from an insertion hole 3 formed in the top plate 2. A trivet 4 is also installed on the top plate 2 for placing a cooking container such as a pot for holding ingredients (food to be cooked) above the gas burner 10. The trivet 4 has multiple trivet claws 4b (six in the illustrated example) arranged radially and supported by an annular frame 4a surrounding the gas burner 10. The cooking container is placed on the trivet claws 4b and heated from below by the gas burner 10.

[0026] The gas burner 10 is composed of a burner body 11 serving as a base, a burner head 13 placed on the burner body 11, a thermocouple 16 located close to the outer peripheral surface of the burner body 11 and protruding above the top plate 2, and a temperature sensor 17 located protruding from the center of the upper surface of the burner head 13.

[0027] A plurality of vertically elongated main flame ports 14 are opened at predetermined intervals in the circumferential direction on the outer peripheral surface of the burner head 13 mounted on the burner body 11. A mixture of fuel gas and air is ejected from these main flame ports 14, and when ignited by a spark plug (not shown), combustion of the mixture begins and a flame is formed outside the main flame ports 14. In addition, flame stabilizing ports 15, which are shorter in vertical dimension than the main flame ports 14, are opened between adjacent main flame ports 14. Mixed gas is also ejected from these flame stabilizing ports 15, and a flame smaller than that of the main flame ports 14 is formed outside the flame stabilizing ports 15.

[0028] Thermocouple 16 functions as a flame detection means capable of detecting a flame caused by the combustion of mixed gas, as will be described later, and generates a thermoelectromotive force when its tip is heated by the flame, making it possible to detect ignition or extinguishing of a fire based on the thermoelectromotive force of thermocouple 16. Temperature sensor 17 also measures the temperature of the cooking vessel by abutting its upper end surface against the bottom surface of the cooking vessel.

[0029] FIG. 2 is a vertical cross-sectional view showing the internal structure of the gas burner 10 of this embodiment. The burner body 11 is formed by facing and airtightly joining two metal sheets (an outer plate 11a and an inner plate 11b) formed by pressing thin plates such as stainless steel. An annular mixing chamber 11c is formed inside the burner body 11. The upper end of the outer plate 11a is bent inward to form an annular mounting surface 11d, and the upper part of the outer plate 11a protrudes above the top plate 2 through the insertion hole 3 (see FIG. 1). The burner head 13 is mounted on this mounting surface 11d. Note that the burner body 11 is not limited to being made of metal sheet, and may be formed by casting (die casting) or the like.

[0030] A mixing pipe 12 that communicates with the mixing chamber 11c extends from the burner body 11, and a nozzle 31 at the tip of a gas supply pipe 30 that supplies fuel gas is installed facing the open end 12a of the mixing pipe 12. The gas supply pipe 30 is provided with an on-off valve 32 that opens and closes the gas supply pipe 30, and a flow rate control valve 33 that adjusts the flow rate of the fuel gas in the gas supply pipe 30. When the on-off valve 32 is opened, fuel gas is supplied to the nozzle 31 at a flow rate corresponding to the opening of the flow rate control valve 33, and the fuel gas injected from the nozzle 31 flows into the mixing pipe 12 together with primary air for combustion that is sucked in from the surrounding area. The fuel gas and primary air are mixed as they pass through the mixing pipe 12, and the mixed gas is supplied to the mixing chamber 11c.

[0031] The burner head 13 is made of a metal material such as aluminum alloy or brass and is formed into an annular shape by casting or die casting, etc. A cylindrical wall 13a hangs downward from the outer edge of the burner head 13, and a cylindrical fitting cylinder 13b hangs downward from the inner edge and is longer than the cylindrical wall 13a.

[0032] When the burner head 13 is mounted on the burner body 11, the fitting tube 13b is fitted inside the inner plate 11b, and the lower end surface of the cylindrical wall 13a is brought into contact with the annular mounting surface 11d located around the upper opening of the mixing chamber 11c. This causes the upper opening of the mixing chamber 11c to be covered by the burner head 13. Furthermore, as will be described in detail later, the lower end surface of the cylindrical wall 13a is recessed with multiple radially transverse grooves spaced apart in the circumferential direction, and multiple flame ports (main flame port 14 and flame holding port 15) are defined by the lower end surface of the cylindrical wall 13a abutting against the mounting surface 11d. In the illustrated example, the mounting surface 11d is inclined downward from the radial outside to the radial inside, and accordingly, the lower end surface of the cylindrical wall 13a is similarly inclined.

[0033] The inside of the fitting tube 13b of the burner head 13 is a vertical passage 13c that passes through the gas burner 10 in the vertical direction, and a support pole 18 with a temperature sensor 17 attached to its upper end is inserted into this vertical passage 13c. The temperature sensor 17 has an upper portion that protrudes from the upper surface of the burner head 13 and is movable in the axial direction (vertical direction) of the support pole 18, and is biased upward by a biasing spring (not shown), so that the upper end surface of the temperature sensor 17 abuts against the bottom surface of a cooking container placed on the trivet 4.

[0034] 3 is an enlarged cross-sectional view of the main flame nozzle 14 and the flame stabilizing nozzle 15 defined by placing the cylindrical wall 13a of the burner head 13 on the mounting surface 11d of the burner body 11. First, FIG. 3(a) shows a longitudinal cross-sectional view cut at the position of the main flame nozzle 14. As shown in the figure, a deep groove (main flame nozzle groove 13d) extending radially across the lower end surface of the cylindrical wall 13a at the position of the main flame nozzle 14 is recessed. When the lower end surface of the cylindrical wall 13a abuts against the mounting surface 11d, the main flame nozzle groove 13d and the mounting surface 11d define the main flame nozzle 14, which is connected to the mixing chamber 11c and opens to the outer periphery of the cylindrical wall 13a. The mixed gas in the mixing chamber 11c is ejected from the main flame nozzle 14, and when combustion of the mixed gas is initiated by ignition, a flame is formed outside the main flame nozzle 14. As described above, the flow rate of the fuel gas can be adjusted by the flow rate control valve 33 of the gas supply pipe 30, and the flow rate of the mixed gas supplied to the mixing chamber 11c changes depending on the opening of the flow rate control valve 33, so it is possible to change the heat output of the gas burner 10 that heats the cooking vessel. Note that the main flame port groove 13d in this embodiment corresponds to the "flame port groove" of the present invention, and the main flame port 14 in this embodiment corresponds to the "flame port" of the present invention.

[0035] 3(b) shows a longitudinal cross section cut at the position of flame stabilizing port 15. A groove (flame stabilizing port groove 13e) shallower than main flame stabilizing port groove 13d is recessed radially across the lower end surface of cylindrical wall 13a at the position of flame stabilizing port 15, and when the lower end surface of cylindrical wall 13a abuts against mounting surface 11d, flame stabilizing port 15, which communicates with mixing chamber 11c and opens to the outer periphery of cylindrical wall 13a, is defined by flame stabilizing port groove 13e and mounting surface 11d. Like main flame port 14, mixed gas from mixing chamber 11c is also ejected from flame stabilizing port 15, and because flame stabilizing port 15 is smaller than main flame port 14 (its vertical dimension is shorter), a smaller flame than main flame port 14 is formed outside flame stabilizing port 15. As mentioned above, the flame stabilizing ports 15 are opened between adjacent main flame ports 14, and the small flames formed outside the flame stabilizing ports 15 ensure the flame spread performance and flame stability of the large flames formed outside the main flame ports 14.

[0036] These main flame ports 14 and flame holding ports 15 are arranged alternately at intervals in the circumferential direction around the outer periphery of the cylindrical wall 13a of the burner head 13 mounted on the burner body 11. As mentioned above, a thermocouple 16 is installed as flame detection means for detecting a flame caused by the combustion of the mixed gas, and the tip of the thermocouple 16 is heated by the flame to generate a thermoelectromotive force to detect the flame. If a flame is not detected, the on-off valve 32 of the gas supply pipe 30 is closed to cut off the supply of fuel gas. In the gas burner 10 of this embodiment, in order to stabilize the flame detection using the thermocouple 16, the flame port to be detected by the thermocouple 16 (hereinafter referred to as the detection flame port) is configured as follows.

[0037] 4 is an explanatory diagram showing the configuration of the detection flame port 20 in the gas burner 10 of this embodiment. First, FIG. 4(a) is an enlarged perspective view of a portion of the cylindrical wall 13a of the burner head 13 before it is placed on the burner body 11, viewed obliquely from below. The burner head 13 of this embodiment includes a predetermined pair of adjacent detection flame port grooves 21 among the plurality of main flame port grooves 13d recessed in the cylindrical wall 13a, a main partition wall portion 22 sandwiched between the pair of detection flame port grooves 21 in the cylindrical wall 13a, and a pair of sub-partition wall portions 23 adjacent to the pair of detection flame port grooves 21 on the cylindrical wall 13a on the opposite side (outside in the circumferential direction) from the main partition wall portion 22. In addition, a canopy portion 24 extends radially outward from the upper end of the outer peripheral surface of the cylindrical wall 13a, and this canopy portion 24 protrudes above the detection flame port groove 21, the main partition wall portion 22, and the sub-partition wall portion 23.

[0038] The outer peripheral surface of the sub-partition wall portion 23 is located on approximately the same circumference as the outer peripheral surfaces of the main partition wall portion 22 and the other portions of the cylindrical wall 13a excluding the sub-partition wall portion 23 (hereinafter referred to as the base portion). On the other hand, as shown in the figure, the outer peripheral surface of the main partition wall portion 22 is recessed radially inward of the burner head 13 with respect to the outer peripheral surfaces of the base portion of the cylindrical wall 13a and the outer peripheral surfaces of the sub-partition wall portion 23. Incidentally, flame stabilization grooves 13e are recessed in the lower end surfaces of the outer sides of the pair of sub-partition wall portions 23 and the main partition wall portion 22 in the circumferential direction of the burner head 13.

[0039] Furthermore, a first protrusion 25 protrudes from the upper part of the outer peripheral surface of the main partition wall portion 22 toward the outside in the radial direction of the burner head 13. This first protrusion 25 is directly connected to the lower surface of the eaves portion 24, and protrudes further outward in the radial direction of the burner head 13 than the outer peripheral surface of the sub-partition wall portion 23. Furthermore, a pair of second protrusions 26 corresponding to each of the pair of sub-partition wall portions 23 and located on the outside in the radial direction of the burner head 13 are suspended from the lower surface of the eaves portion 24, and the second protrusions 26 in this embodiment are directly connected to the outer peripheral surface of the sub-partition wall portion 23.

[0040] As shown in the figure, the lower ends of the pair of second protrusions 26 are located higher than the lower ends of the first protrusions 25. Furthermore, the outer end of the first protrusion 25 in the radial direction of the burner head 13 is located on approximately the same circumference as the outer end of the second protrusion 26. In addition, the width of the base of the first protrusion 25 in the circumferential direction of the burner head 13 is approximately the same as the width of the main partition wall portion 22.

[0041] 4(b) shows an enlarged view of the appearance of the detection flame port 20 opening on the outer periphery of the cylindrical wall 13a of the burner head 13 mounted on the burner body 11. When the lower end surface of the cylindrical wall 13a abuts against the mounting surface 11d, the pair of detection flame port grooves 21 and the mounting surface 11d define a pair of detection flame ports 20. That is, each detection flame port 20 is surrounded by the main partition wall portion 22, the sub-partition wall portion 23, the eaves portion 24, and the mounting surface 11d, and a first convex portion 25 and a second convex portion 26 are arranged on the left and right sides of the upper part of the detection flame port 20.

[0042] As shown by the dashed line in the figure, the thermocouple 16 is disposed opposite the outer peripheral surface of the main partition wall portion 22, with the tip of the thermocouple 16 located below the lower end of the first convex portion 25. In addition, the main partition wall portion 22 has a flame stabilizing port 15 opening below the first convex portion 25. Furthermore, a flame stabilizing port 15 also opens outside the pair of detection flame ports 20 in the circumferential direction of the burner head 13, and outside that, the normal main flame port 14 opens.

[0043] FIG. 5 is an explanatory diagram showing flames formed outside a pair of detection nozzles 20 in the gas burner 10 of this embodiment. FIG. 5 illustrates flames formed when the gas burner 10 is at high heat output. In the gas burner 10, as heat output increases, the flames of adjacent pairs of detection nozzles 20 tend to merge. This combined flame is prone to poor combustion due to a lack of secondary air, and since it extends radially outward in search of secondary air, the flame's position relative to the thermocouple 16 changes, making it difficult to properly detect. In the gas burner 10 of this embodiment, a first protrusion 25 is provided on the upper portion of the outer circumferential surface of the main partition wall 22 sandwiched between the pair of detection nozzles 20. This prevents the flames at the pair of detection nozzles 20 from merging, and allows the tip (upper) portion of the flame to be divided into two, as shown in FIG. 5. The tip of the thermocouple 16 is then positioned between the two flames.

[0044] However, even if the flame in the pair of detection flame ports 20 is divided into two by the first protrusions 25 provided on the main partition wall portion 22, the detection of the flame by the thermocouple 16 may become unstable, and therefore, in the gas burner 10 of this embodiment, a pair of second protrusions 26 is further added to stabilize the detection of the flame by the thermocouple 16. This point will be explained below by comparing the case where the second protrusions 26 are not provided with the case where they are provided.

[0045] 6 is an explanatory diagram comparing the flames formed outside the pair of detection flame ports 20 between cases where there is and where there is not the second convex portion 26. In FIG. 6, a cross section of the burner head 13 cut by a horizontal plane at the position where the second convex portion 26 is provided and viewed from below is shown enlarged, along with the flames formed outside the pair of detection flame ports 20 when the gas burner 10 is at high heat output. The dashed circle in the figure indicates the position of the tip of the thermocouple 16.

[0046] 6(a) shows a case where the second protrusion 26 is not provided. As described above, the first protrusion 25 is provided on the upper part of the outer peripheral surface of the main partition wall portion 22 sandwiched between the pair of detection flame nozzle grooves 21, and therefore the flames resulting from the combustion of the mixed gas ejected from each of the pair of detection flame nozzles 20 are prevented from joining together, resulting in the flames being separated into two. Generally, in gas burners 10, as the ambient temperature rises due to prolonged combustion, expanded air with a low oxygen concentration is supplied as secondary air. Therefore, the two flames separated by the pair of detection flame nozzles 20 tend to spread apart toward the outside in the circumferential direction of the burner head 13 in search of the missing oxygen, and the separation of the flames from the thermocouple 16 makes the flame detection by the thermocouple 16 unstable.

[0047] 6(b) shows a case where the second protrusions 26 are provided. As described above, the pair of second protrusions 26 are positioned radially outward of the burner head 13, corresponding to each of the pair of sub-partition wall portions 23, and are suspended from the underside of the eaves portion 24. As the ejected mixed gas flows along the underside of the eaves portion 24 at the upper portion of each detection flame port 20, it is sandwiched between the first protrusion 25 and the second protrusion 26. As shown by the outline arrows in the figure, the ejected mixed gas is directed radially outward from the burner head 13, improving its linearity. By rectifying the ejected mixed gas at the upper portion of each of the pair of detection flame ports 20 in this way, the two flames resulting from the combustion of the mixed gas can be prevented from spreading circumferentially outward from the burner head 13, thereby enabling the thermocouple 16 to maintain an appropriate distance from the flame, stabilizing flame detection.

[0048] In particular, in the gas burner 10 of this embodiment, the second convex portion 26 is directly connected to the outer peripheral surface of the sub-partition wall portion 23, and the distance between the first convex portion 25 and the second convex portion 26 in the circumferential direction of the burner head 13 increases from the inside to the outside in the radial direction of the burner head 13. This makes it possible to reduce the flow rate of the mixed gas passing between the first convex portion 25 and the second convex portion 26, thereby suppressing the flame caused by combustion of the mixed gas from extending radially outward, and making it possible to stabilize flame detection by the thermocouple 16.

[0049] Furthermore, in the gas burner 10 of this embodiment, as described above, the lower end of the second convex portion 26 is located higher than the lower end of the first convex portion 25 (see FIG. 4). Because the second convex portion 26 is shorter than the first convex portion 25, it is less likely to impede the intake of secondary air from the outside in the circumferential direction of the burner head 13, and it is therefore possible to prevent the flames in the pair of detection flame ports 20 from extending radially outward from the burner head 13. Furthermore, above the detection flame port 20, the ejected mixed gas flows along the underside of the eaves portion 24, and therefore even if the second convex portion 26 suspended from the underside of the eaves portion 24 is shorter than the first convex portion 25, the ejected mixed gas can be rectified and the above-mentioned effect can be obtained.

[0050] Additionally, in the gas burner 10 of this embodiment, the outer end of the first convex portion 25 in the radial direction of the burner head 13 is positioned on approximately the same circumference as the outer end of the second convex portion 26. Even if the flames in the pair of detection flame ports 20 extend radially outward of the burner head 13 by the amount of the addition of the pair of second convex portions 26 as described above, by ensuring that the amount of projection of the first convex portion 25 radially outward is equal to or greater than that of the second convex portions 26, it is possible to maintain the separation of the two flames.

[0051] The above has explained the flame when the gas burner 10 is at high heat output. Next, we will explain the flame when the gas burner 10 is at low heat output. Fig. 7 is an explanatory diagram showing the flame formed outside the pair of detection flame ports 20 when the gas burner 10 is at low heat output. Fig. 7 shows an enlarged cross section of the burner head 13 taken along a horizontal plane below the lower end of the first convex portion 25 and viewed from below, along with the flame. The dashed circle in the figure indicates the position of the tip of the thermocouple 16.

[0052] When the gas burner 10 is operating at low heat output, the flow rate of the mixed gas is low, and the mixed gas flows out of the pair of detection flame ports 20 while slowly spreading along the outer circumferential surfaces of the main partition wall portion 22 and the sub-partition wall portion 23. As a result, a flame resulting from the combustion of the mixed gas is formed so as to cling to the outer circumferential surfaces of the main partition wall portion 22 and the sub-partition wall portion 23. In particular, in the gas burner 10 of this embodiment, the outer circumferential surface of the main partition wall portion 22 is recessed radially inward of the burner head 13 relative to the outer circumferential surface of the sub-partition wall portion 23, which promotes the combination of the two flames at the lower portions of the pair of detection flame ports 20 and improves flame stability. In addition, as described above, the flame stability port 15 is opened at the lower portion of the outer circumferential surface of the main partition wall portion 22 (see FIG. 4), and the small flame formed outside this flame stability port 15 further improves the flame stability of the pair of detection flame ports 20.

[0053] Then, by combining the two flames at the bottom of the pair of detection flame ports 20, the combined flame is suppressed upward by the lower surface of the first convex portion 25, and therefore spreads radially outward of the burner head 13. Since the combined flame can be directed toward the thermocouple 16 along the lower surface of the first convex portion 25 in this way, it becomes possible to stabilize flame detection by the thermocouple 16 when the gas burner 10 is operating at low flame power. In particular, in the gas burner 10 of this embodiment, the width of the base of the first convex portion 25 in the circumferential direction of the burner head 13 is approximately the same as the width of the main partition wall portion 22, and therefore the effect of suppressing the upper part of the combined flame by the lower surface of the first convex portion 25 and directing it toward the thermocouple 16 can be enhanced.

[0054] Furthermore, the gas burner 10 of this embodiment has features not only on the outer circumferential side of the main partition wall portion 22 and the sub-partition wall portion 23 but also on the inner circumferential side. Fig. 8 is an explanatory diagram focusing on the inner circumferential side of the main partition wall portion 22 and the sub-partition wall portion 23 in the gas burner 10 of this embodiment. Fig. 8 shows an enlarged cross section of the burner head 13 cut by a horizontal plane at a position below the lower end of the first convex portion 25 and viewed from below.

[0055] As shown in the figure, the inner peripheral surfaces of the main partition wall portion 22 and the sub-partition wall portion 23 are located radially inward of the burner head 13 with respect to the inner peripheral surface of the base portion of the cylindrical wall 13a (the other portions excluding the main partition wall portion 22 and the sub-partition wall portion 23). Each detection flame port groove 21 has a parallel region 21a on the outer peripheral side of the main partition wall portion 22, where the distance between the main partition wall portion 22 and the sub-partition wall portion 23 is constant, and also has an expanded region 21b on the inner peripheral side of the main partition wall portion 22, where the distance between the main partition wall portion 22 and the sub-partition wall portion 23 expands toward the inside in the radial direction of the burner head 13.

[0056] In this way, the inner peripheral surfaces of the main partition wall portion 22 and the sub-partition wall portion 23 protrude radially inward of the burner head 13 to extend the detection flame groove 21, and by ensuring the widened region 21b, the mixed gas is smoothly supplied from the mixing chamber 11c to the detection flame groove 21, and by ensuring the parallel region 21a, the mixed gas ejected from the detection flame groove 20 through the detection flame groove 21 can be rectified, making it possible to stabilize the direction of the flame caused by the combustion of the mixed gas at high heat output. As a result, the two flames in the pair of detection flame grooves 20 are prevented from spreading outward in the circumferential direction of the burner head 13, and flame detection by the thermocouple 16 can be stabilized.

[0057] The gas burner 10 of this embodiment has been described above, but the present invention is not limited to the above embodiment and can be embodied in various forms without departing from the spirit of the present invention.

[0058] For example, in the above-described embodiment, the pair of second protrusions 26 extending vertically from the underside of the eave portion 24 are directly connected to the outer circumferential surface of the sub-partition wall portion 23 (see FIG. 4 ). However, as shown in FIG. 9 , the cylindrical second protrusions 26 may be extended vertically from the underside of the eave portion 24, with a gap between the second protrusions 26 and the sub-partition wall portion 23. Even if the second protrusions 26 are not directly connected to the sub-partition wall portion 23, the mixed gas ejected above the detection flame port 20 can be rectified by being sandwiched between the first protrusions 25 and the second protrusions 26 as the mixed gas flows along the underside of the eave portion 24. However, if the second protrusions 26 are directly connected to the sub-partition wall portion 23 as in the above-described embodiment, the rectification effect of the mixed gas ejected can be further enhanced.

[0059] In the above-described embodiment, the outer peripheral surface of the main partition wall portion 22 is recessed radially inward of the burner head 13 relative to the outer peripheral surface of the sub-partition wall portion 23. However, even in a gas burner 10 in which the outer peripheral surfaces of the main partition wall portion 22 and the sub-partition wall portion 23 are positioned on approximately the same circumference, by providing the first convex portion 25 and the second convex portion 26, the mixed gas ejected at high firepower is sandwiched between the first convex portion 25 and the second convex portion 26 above the detection flame nozzle 20 and rectified, thereby stabilizing flame detection by the thermocouple 16 as in the above-described embodiment. However, if the outer peripheral surface of the main partition wall portion 22 is recessed radially inward of the burner head 13 relative to the outer peripheral surface of the sub-partition wall portion 23 as in the above-described embodiment, the combination of the two flames can be promoted below the pair of detection flame nozzles 20 at low firepower, improving flame stability.

[0060] In the above-described embodiment, the eaves portion 24 is provided to extend above the detection flame groove 21, the main partition wall portion 22, and the sub-partition wall portion 23. However, the eaves portion 24 only needs to extend above at least the detection flame groove 21, the main partition wall portion 22, and the sub-partition wall portion 23, and may be provided around the entire periphery of the cylindrical wall 13a of the burner head 13.

[0061] Furthermore, in the above-described embodiment, the distance between the first convex portion 25 and the second convex portion 26 in the circumferential direction of the burner head 13 increases from the inside to the outside in the radial direction of the burner head 13. However, the distance between the first convex portion 25 and the second convex portion 26 may be constant. In addition, in the above-described embodiment, the outer end of the first convex portion 25 in the radial direction of the burner head 13 is located on approximately the same circumference as the outer end of the second convex portion 26. However, the outer end of the first convex portion 25 may be located further outward in the radial direction of the burner head 13 than the outer end of the second convex portion 26.

[0062] In the above-described embodiment, the upper part of the gas burner 10 protrudes from the insertion hole 3 formed in the top plate 2 of the gas stove 1. However, the gas burner 10 may be installed inside a grill (not shown) built into the gas stove 1 as a heat source for the grill. Furthermore, in the above-described embodiment, the gas stove 1 has been described as an example of a cooking device equipped with the gas burner 10. However, the cooking device may be equipped with an electromagnetic induction heating unit (so-called IH unit) that heats a metal cooking vessel by passing electricity through a magnetic force generating coil, in addition to the gas burner 10 as heating means. [Explanation of symbols]

[0063] 1...gas stove, 2...top plate, 3...insertion hole, 4...trivet, 4a...frame body, 4b...trivet claws, 10...gas burner, 11...burner body, 11a...outer plate, 11b...Inner plate, 11c...Mixing chamber, 11d...Placement surface, 12...mixing tube, 12a...open end, 13...burner head, 13a... cylindrical wall, 13b... fitting tube, 13c... vertical passage, 13d...Main flame opening groove, 13e...Flame holding groove, 14...Main flame opening, 15...flame holding port, 16...thermocouple, 17...temperature sensor, 18...Support pole, 20...Detection flame port, 21...Detection flame port groove, 21a...parallel region, 21b...widening region, 22...main partition wall portion, 23... Sub-partition wall portion, 24... Eaves portion, 25... First convex portion, 26... second protrusion, 30... gas supply pipe, 31... nozzle, 32...Shut-off valve, 33...Flow control valve.

Claims

1. a burner body having an annular mixing chamber to which a mixture of fuel gas and air is supplied, and a burner head mounted on the burner body and covering an upper opening of the mixing chamber, wherein a plurality of radially transverse flame port grooves are recessed at intervals in the circumferential direction in the lower end surface of a cylindrical wall extending vertically downward from the outer edge portion of the burner head, and an annular mounting surface is provided around the upper opening of the mixing chamber on the burner body, and when the burner head is mounted on the burner body and the lower end surface of the cylindrical wall abuts against the mounting surface, a plurality of flame ports communicating with the mixing chamber and opening into the outer peripheral surface of the cylindrical wall are defined by the plurality of flame port grooves and the mounting surface, and flames formed by combustion of the mixture gas ejected from the flame ports can be detected by flame detection means; The burner head is a predetermined pair of adjacent detection flame grooves among the plurality of flame grooves; a main partition wall portion sandwiched between the pair of detection flame grooves in the cylindrical wall; a pair of sub-partition wall portions adjacent to the pair of detection flame grooves on the cylindrical wall opposite to the main partition wall portions; a visor portion extending radially outward from an upper end of the outer peripheral surface of the cylindrical wall and projecting upward at least above the detection flame groove, the main partition wall portion, and the sub-partition wall portion; Equipped with the flame detection means is disposed opposite to the outer peripheral surface of the main partition wall portion, a first protrusion provided from an upper portion of the outer peripheral surface of the main partition wall portion to the outside in the radial direction of the burner head and protruding beyond the outer peripheral surface of the sub-partition wall portion, the first protrusion being directly connected to the lower surface of the eave portion; A pair of second protrusions are provided on the outer side of the burner head in the radial direction, corresponding to the pair of sub-partition wall portions, and are vertically extended from the lower surface of the eave portion. A gas burner characterized by:

2. 2. The gas burner according to claim 1, The lower ends of the pair of second protrusions are located higher than the lower ends of the first protrusions. A gas burner characterized by:

3. 3. The gas burner according to claim 1 or 2, The outer end of the first protrusion in the radial direction of the burner head is located on approximately the same circumference as the outer end of the second protrusion or on the outer side in the radial direction. A gas burner characterized by:

4. 2. The gas burner according to claim 1, The outer peripheral surface of the main partition wall portion is recessed radially inward of the burner head relative to the outer peripheral surface of the sub-partition wall portion. A gas burner characterized by:

5. 2. The gas burner according to claim 1, The width of the first protrusion in the circumferential direction of the burner head is approximately the same as the width of the main partition wall portion. A gas burner characterized by:

6. 2. The gas burner according to claim 1, the second protrusion is directly connected to the outer peripheral surface of the sub-partition wall portion, The distance between the first convex portion and the second convex portion in the circumferential direction of the burner head increases from the inside toward the outside in the radial direction of the burner head. A gas burner characterized by:

7. 2. The gas burner according to claim 1, inner circumferential surfaces of the main partition wall portion and the sub-partition wall portion are located radially inward of the burner head with respect to inner circumferential surfaces of other portions of the cylindrical wall excluding the main partition wall portion and the sub-partition wall portion, The detection flame groove has a parallel region on the outer periphery of the main partition wall portion where the distance between the main partition wall portion and the sub-partition wall portion is constant, and has a widened region on the inner periphery of the main partition wall portion where the distance between the main partition wall portion and the sub-partition wall portion widens toward the inside in the radial direction of the burner head. A gas burner characterized by:

8. A cooking appliance comprising the gas burner according to claim 1, for heating food by combustion in the gas burner.

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