Gas burner and gas stove

Abstract

To suppress the adverse effect on combustibility caused by a decrease in the excess air ratio of the air-fuel mixture due to low-density air being sucked in as primary air from the lower end of a throat portion as a result of temperature rise caused by long-term combustion in a gas burner comprising a burner body 41 having a throat portion 415 extending in the vertical direction, a burner cap 42 defining an annular chamber 43 communicating with the throat portion between the burner body and the burner cap, and a plurality of flame ports 44 on the outer periphery of the chamber, and a throat facing plate 45 facing the upper end of the throat portion.SOLUTION: A gas burner is provided with displacement means 46 for displacing the throat facing plate 45 upward in accordance with an increase in temperature within the chamber 43. The displacement means 46 is composed of, for example, a tapered surface 461 on the inner periphery of the chamber 43, and leg pieces 462 made of a shape memory alloy that hang down from the periphery of the throat facing plate 45 and abut against the tapered surface 461.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gas burner and gas stove which include a burner body having a throat portion extending in the vertical direction, and a burner cap which is placed on the burner body and defines an annular chamber between the burner body and the burner cap which communicates with the throat portion, and which defines a plurality of flame ports at circumferential intervals on the outer periphery of the chamber, and in which fuel gas is sprayed from a nozzle provided below the throat portion toward the lower end opening of the throat portion. [Background technology]

[0002] Conventionally, as this type of gas burner, there is known one that is provided with a throat facing plate that faces above the upper end opening of the throat portion, radially diffuses the gas flow ejected from the upper end opening of the throat portion, and draws in primary air from the lower end opening of the throat portion (see, for example, Patent Document 1). This throat facing plate is provided integrally with the burner body. Even if the temperature inside the chamber changes, the gap between the upper end opening of the throat portion and the throat facing plate is kept constant.

[0003] However, when a gas burner is burned for a long time, the burner body becomes hot, and the air that is heated around the burner body and has a lower density is drawn in from the lower end opening of the throat as primary air. As a result, the excess air ratio of the mixture (mixture of fuel gas and primary air) supplied into the chamber through the throat decreases, adversely affecting combustibility. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-52947 A Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above, an object of the present invention is to provide a gas burner that can suppress the adverse effects on combustion that can be caused by long-term combustion, and a gas stove equipped with this gas burner. [Means for solving the problem]

[0006] In order to solve the above problems, the first invention of the present application is a gas burner comprising a burner body having a throat portion extending in the vertical direction, and a burner cap placed on the burner body and defining an annular chamber communicating with the throat portion between the burner body and the burner cap, and defining a plurality of flame ports at circumferential intervals on the outer periphery of the chamber, in which fuel gas is injected from a nozzle provided below the throat portion toward the lower end opening of the throat portion, and is characterized in that it comprises a throat opposing plate that faces above the upper end opening of the throat portion and radially diffuses the gas flow ejected from the upper end opening of the throat portion, thereby exerting the effect of sucking in primary air from the lower end opening of the throat portion, and is characterized in that it comprises a displacement means that displaces the throat opposing plate upward relative to the upper end opening of the throat portion as the temperature in the chamber rises. A second aspect of the present invention is a gas stove comprising a stove burner configured as the gas burner of the first aspect of the present invention.

[0007] According to the gas burner of the first invention, when the temperature of the burner body rises due to the long burning of the gas burner, the gap between the upper end opening of the throat portion and the throat facing plate becomes wider due to the upward displacement of the throat facing plate caused by the temperature rise in the chamber. Therefore, the air flow resistance in this gap decreases, and the amount of primary air sucked in increases. As a result, the decrease in density due to the temperature rise of the primary air is compensated for by the increase in the amount of sucked in, and the decrease in the excess air ratio of the mixture is suppressed. Therefore, it is possible to suppress the adverse effect on combustibility caused by the long burning of the gas burner. Furthermore, according to the gas stove of the second invention, even if the stove burner is burned for a long period of time for cooking, adverse effects on combustion can be suppressed, so good cooking performance can be ensured.

[0008] In the first invention, the inner peripheral surface of the chamber or the upper peripheral surface of the throat is formed into a tapered surface whose normal is inclined upward from the horizontal direction, and a plurality of legs are provided that hang down from a plurality of circumferential points on the periphery of the throat opposing plate and abut against the tapered surface, and it is preferable that the legs are formed of a shape memory alloy or that the burner body and the throat opposing plate are formed of materials with different thermal expansion coefficients so that the pressure of the legs against the tapered surface increases with the temperature rise in the chamber. Here, if the pressure of the legs against the tapered surface increases, the throat opposing plate is displaced upward due to the inclination of the tapered surface. Therefore, the tapered surface and the legs constitute the displacement means. This is advantageous because the throat opposing plate can be reliably displaced with a relatively simple configuration. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cutaway side view of a main part of a gas stove equipped with a gas burner according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the gas burner according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Referring to FIG. 1, 1 denotes a stove body of a gas stove. The stove body 1 has an open top, and a top plate 2 is placed to cover the top plate. A burner opening 2a is formed in the top plate 2. A trivet 3 is placed on the top plate 2 so as to surround the burner opening 2a. The gas stove is also equipped with a stove burner 4 formed of a gas burner according to an embodiment of the present invention, which is exposed on the top plate 2 through the burner opening 2a. A cooking vessel such as a pot placed on the multiple trivet claws 3a of the trivet 3 is heated by the stove burner 4.

[0011] The stove burner 4 includes a burner body 41 and a burner cap 42 placed on the burner body 41, and is held by a holder 5 attached to a base plate 1a provided at the bottom of the stove main body 1. Referring also to Fig. 2, the burner body 41 has a disk-shaped base 411, an annular peripheral wall 412 erected on the outer periphery of the base 411, a truncated cone-shaped raised portion 413 protruding from the center of the upper surface of the base 411, a cylindrical hanging portion 414 hanging from the center of the lower surface of the base 411, and a throat portion 415 that penetrates the raised portion 413 and the hanging portion 414 and opens upward and downward.

[0012] The burner cap 42 is disk-shaped, and the outer periphery of the lower surface is seated on the upper end of the peripheral wall 412 of the burner body 41. An annular chamber 43 communicating with the throat portion 415 is defined between the burner body 41 and the burner cap 42. The peripheral wall 412 is also provided with a plurality of grooves extending downward from its upper end at intervals in the circumferential direction. The upper ends of these grooves are closed by the burner cap 42, so that a plurality of flame ports 44 are defined by these grooves on the outer periphery of the chamber 43. Furthermore, a recess 412a recessed radially inward and a target portion 412b extending above the recess 412a are provided at one circumferential location on the peripheral wall 412 of the burner body 41.

[0013] The holder 5 has a base portion 51, a support portion 52 erected on one side of the base portion 51, and a seat plate portion 53, which is cantilevered by the support portion 52 and has a cylindrical portion 53a erected on its upper surface, through which the hanging portion 414 of the burner body 41 can penetrate. An engagement groove 53b extending downward from the upper end is formed at one circumferential position of the cylindrical portion 53a. When the burner body 41 is set in the holder 5, the burner body 41 is inserted into the inner periphery of the seat plate portion 53 from the hanging portion 414 side, and the base portion 411 of the burner body 41 is seated on the upper end of the cylindrical portion 53a with the protruding portion 414a protruding at one circumferential position on the upper outer circumferential surface of the hanging portion 414 engaged with the engagement groove 53b. This allows the burner body 41 to be phased and centered with respect to the holder 5.

[0014] The nozzle 6 is attached to the base portion 51 of the holder 5 below the throat portion 415, and a gas passage hole 51a is formed to reach the nozzle 6. Fuel gas is injected from the nozzle 6 toward the lower end opening 415a of the throat portion 415. In addition, an ignition electrode 7 is attached to the support portion 52 of the holder 5, which fits into the recess 412a of the peripheral wall portion 412 of the burner body 41 and faces the target portion 412b.

[0015] The burner 4 further includes a disk-shaped throat facing plate 45 that faces the upper end opening 415b of the throat portion 415. The gas flow ejected from the upper end opening 415b of the throat portion 415 hits the throat facing plate 45 and is diffused in the radial direction, thereby producing the effect of sucking in primary air from the lower end opening 415a of the throat portion 415, the so-called radial venturi effect.

[0016] However, when the burning time of the stove burner 4 becomes long, the burner body 41 becomes hot, and the air that is heated around the burner body 41 and has a lower density is sucked in as primary air from the lower end opening 415a of the throat part 415. Therefore, the excess air ratio of the mixture (mixture of fuel gas and primary air) supplied to the chamber 43 through the throat part 415 decreases, and the combustibility is adversely affected. Therefore, in this embodiment, the stove burner 4 is provided with a displacement means 46 that displaces the throat facing plate 45 upward relative to the upper end opening 415b of the throat part 415 as the temperature in the chamber 43 rises. The displacement means 46 will be described in detail below.

[0017] The outer peripheral surface of the raised portion 413, which is the inner peripheral surface of the chamber 43, is formed as a tapered surface whose normal is inclined upward with respect to the horizontal direction, that is, a tapered surface 461 whose diameter gradually decreases toward the top. In addition, a plurality of leg pieces 462 are provided that hang down from a plurality of points in the circumferential direction of the periphery of the throat opposing plate 45 and abut against the tapered surface 461. These leg pieces 462 are formed of a shape memory alloy so that the pressure of the leg pieces 462 against the tapered surface 461 increases with the temperature rise in the chamber 43, that is, so that the leg pieces 462 bend radially inward. When the pressure of the leg pieces 462 against the tapered surface 461 increases, the throat opposing plate 45 is displaced upward due to the inclination of the tapered surface 461, as shown by the imaginary line in FIG. 2. Therefore, the tapered surface 461 and the leg pieces 462 form the displacement means 46.

[0018] Here, when the burner body 41 temperature rises due to the burner burner 4 being burned for a long time, the temperature in the chamber 43 also rises, and the throat facing plate 45 is displaced upward by the displacement means 46, and the gap between the upper end opening 415b of the throat portion 415 and the throat facing plate 45 becomes wider. Therefore, the air flow resistance in this gap decreases, and the amount of primary air suction increases. As a result, the decrease in density due to the increase in temperature of the primary air is compensated for by the increase in the amount of suction, and the decrease in the excess air ratio of the mixture is suppressed. Therefore, even if the burner burner 4 is burned for a long time for cooking, it is possible to suppress the adverse effect on the combustibility and ensure good cooking performance.

[0019] In this embodiment, the leg piece 462 is integral with the throat opposing plate 45, and the throat opposing plate 45 is also formed from the same shape memory alloy material as the leg piece 462. However, the leg piece 462 may be separate from the throat opposing plate 45, and only the leg piece 462 may be formed from the shape memory alloy.

[0020] Furthermore, instead of forming the leg pieces 462 from a shape memory alloy, the burner body 41 may be formed from a material having a larger thermal expansion coefficient than the material from which the throat opposing plate 45 is formed, so that the pressure of the leg pieces 462 against the tapered surface 461 increases with an increase in temperature in the chamber 43. In this case as well, the throat opposing plate 45 is displaced upward with an increase in temperature in the chamber 43, and the same effect as in the above embodiment can be obtained.

[0021] Although the embodiment of the present invention has been described above, the present invention is not limited thereto. For example, the inner peripheral surface of the raised portion 413, which is the upper peripheral surface of the throat portion 415, may be formed as a tapered surface whose normal line is inclined upward relative to the horizontal direction, that is, a tapered surface whose diameter gradually increases upward, and the leg piece may be abutted against this tapered surface. In this case, the leg piece is made of a shape memory alloy that bends radially outward with an increase in temperature so that the pressure of the leg piece against the tapered surface increases with an increase in temperature in the chamber 43, or the throat facing plate 45 is made of a material with a larger thermal expansion coefficient than the material of the burner body 41. In addition, the displacement means 46 can be made of something other than the tapered surface 461 and the leg piece 462 of the above embodiment, but if the displacement means 46 is made of the tapered surface 461 and the leg piece 462, the throat facing plate 45 can be reliably displaced with a relatively simple configuration, which is advantageous. Furthermore, in the above embodiment, the present invention is applied to the stove burner 4, but the present invention can be similarly applied to gas burners other than stove burners. [Explanation of symbols]

[0022] 4...cooker burner (gas burner), 41...burner body, 415...throat portion, 415a...lower end opening of throat portion, 415b...upper end opening of throat portion, 42...burner cap, 43...chamber, 44...flame port, 45...throat opposing plate, 46...displacement means, 461...tapered surface, 462...leg piece portion.

Claims

1. A gas burner comprising: a burner body having a throat portion extending in a vertical direction; and a burner cap placed on the burner body, defining an annular chamber between the burner body and the burner body that communicates with the throat portion, and defining a plurality of flame ports at circumferential intervals on the outer periphery of the chamber, wherein fuel gas is injected from a nozzle provided below the throat portion toward a lower end opening of the throat portion, A throat facing plate is provided above the upper end opening of the throat portion, and radially diffuses the gas flow ejected from the upper end opening of the throat portion, thereby drawing in primary air from the lower end opening of the throat portion. A gas burner comprising: a displacement means for displacing a throat-facing plate upward relative to an upper end opening of a throat portion as a temperature inside the chamber increases.

2. 2. A gas burner as claimed in claim 1, characterized in that the inner peripheral surface of the chamber or the upper peripheral surface of the throat portion is formed into a tapered surface whose normal is inclined upward with respect to the horizontal direction, and a plurality of leg pieces are provided hanging down from a plurality of points in the circumferential direction of the peripheral edge of the throat opposing plate and abutting against the tapered surface, the leg pieces are formed from a shape memory alloy so that the pressure of the leg pieces against the tapered surface increases as the temperature inside the chamber increases, and the tapered surface and the leg pieces constitute the displacement means.

3. 2. A gas burner as claimed in claim 1, characterized in that the inner peripheral surface of the chamber or the upper inner peripheral surface of the throat portion is formed into a tapered surface whose normal is inclined upward with respect to the horizontal direction, a plurality of leg pieces are provided hanging down from a plurality of points in the circumferential direction of the peripheral edge of the throat opposing plate and abutting against the tapered surface, the burner body and the throat opposing plate are formed of materials having different thermal expansion coefficients so that the pressure of the leg pieces against the tapered surface increases as the temperature inside the chamber increases, and the displacement means is constituted by the tapered surface and the leg pieces.

4. A gas stove comprising a stove burner comprising the gas burner according to any one of claims 1 to 3.

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