A burner for a gas hob

Abstract

The invention relates to a burner for a hob, comprising a lower part (40) surrounding a mixing chamber (42) in the form of a bowl; an intermediate plate (16) that sits on top of the mouth of the mixing chamber (42) and having a vertical venturi tube (17) extending into the mixing chamber (42) at its center; an upper part (10) having a rim (12) extending downward from the outer periphery of the intermediate plate (16) and a flame crown (14) extending upward in the opposite direction, formed by a plurality of spaced teeth (15); and a flat upper cap (20) covering the flame crown (14) from above. When disposed on the intermediate plate (16), the burner comprises an inner channel (11) arranged to enter the upper part (10) from the inner corner of the rim (12) in a manner that increases the volume of the mixing chamber (42).

Description

[0001] A BURNER FOR A GAS HOB

[0002] TECHNICAL FIELD

[0003] The present invention relates to a burner, particularly a burner for a gas hob.

[0004] STATE OF THE ART

[0005] In a domestic gas hob, one or more gas burners are disposed on a flat cooktop, and each gas burner is surrounded by a support grate. A burner generally comprises a mixing chamber where air and gas are mixed, a top plate positioned above it with gas passage openings and a flame crown, and an upper cap covering the top plate.

[0006] One or more gas burners in the hob are connected to a gas distribution pipe, and the flow rate of gas supplied to the burner is adjusted via a gas valve configured with a corresponding rotary control element arranged near the front of the hob’s housing. A thermoelectric safety element and an ignition device are electrically connected to the rotary control element and are mounted on the cooktop by being attached to the burner.

[0007] EP3410011 discloses a gas burner assembly designed particularly for a gas hob. The gas burner includes a burner cap and a burner crown element. The burner cap is arranged to cover the burner crown element. The burner crown element contains a side wall surrounding the inner region of the gas burner assembly. The burner cap is disposed over the side wall of the burner crown element. A plurality of flame ports are formed on the upper side of the side wall. The cross section of the flame port is formed in a spoon-like shape.

[0008] SHORT DESCRIPTION OF THE INVENTION

[0009] The object of the invention is to provide a gas burner for cooking appliances that is lightweight and offers high cooking efficiency.

[0010] In order to achieve the aforementioned objective, the invention relates to a burner for a hob comprising, a lower part surrounding a mixing chamber in the form of a bowl; an intermediate plate that sits on top of the mouth of the mixing chamber and has a vertical venturi tube at its center extending into the mixing chamber; an upper part having a rim extending downward from the outer periphery of the intermediate plate, and oppositely extending upward a flame crown formed by multiple spaced teeth; and a flat upper cap that covers the flame crown from above. The burner includes an inner channel, arranged in such a way that, when the burner is disposed on the intermediate plate, it extends from the inner corner of the rim into the upper part to increase the volume of the mixing chamber. The inner channel radially expands and enlarges the mixing chamber upward and increases its volume, with a single fluid outlet being the vertical venturi tube. At the same time, it reduces the amount of material needed for the upper part and makes the upper part lighter. The supply of air to the mixing chamber is provided in a standard way through the gap between the lower part and the upper part.

[0011] Preferably, the rim of the upper part surrounds the lower part at a radial distance. In this way, a corridor is created between the inner wall of the rim and the corresponding outer wall of the lower part that allows air to enter the mixing chamber.

[0012] Preferably, the inner channel is configured such that it enters the flame crown from its lower end. In this case, it can be formed by hollowing out the thick structure of the flame crown without requiring any additional structural changes to the upper part. Preferably, the inner channel is circular along its entire length. Thus, in the lower edge that covers the mixing chamber from above along the upper part, a channel is formed throughout, thereby ensuring maximum volumetric expansion.

[0013] Preferably, the inner channel has a V-like cross-sectional shape. This shape creates a corner junction that allows the portion of the upper part in which the inner channel is located to be manufactured by injection molding. Furthermore, it was surprisingly discovered that the V- shaped cross section increases fuel richness inside the chamber.

[0014] Preferably, the lower end of the inner channel is aligned with the venturi tube, while its opposite upper end is aligned above the upper edge of the venturi tube. In this way, the ambient air that is involved in the air-fuel mixture in the mixing chamber speeds up and is directed toward the venturi tube.

[0015] Preferably, a mounting collar is disposed in a sealed manner between the upper part and the lower part, having a form suitable for connection to an upper cooktop. The mounting collar enables the burner to be fixed, for example by means of a screw, to a hole made in the cooktop. Thus, the upper part easily rests on the lower part fixed on the cooktop, leaving an air intake corridor between it and the cooktop. Preferably, the upper and lower parts are concentric and made of metal. In this configuration, a compact structure is obtained. Moreover, a gas inlet injector can be disposed in the center of the mixing chamber of the lower part, supplying gas centrally to the burner.

[0016] Preferably, an angled step form is provided between the upper inner corner of the rim and the inner channel. Thus, it becomes possible to position the inner channel toward the flame crown, in which the standard burner teeth are present.

[0017] Preferably, the intermediate plate comprises a flat section extending radially from the upper corner of the venturi tube and an inclined section extending downward at an angle from the outer periphery of this flat section, as well as a further flat section extending from the outer periphery of the inclined section that connects to one end of the inner channel. When the flat section connecting to the inner channel is disposed above the mixing chamber of the lower part so as to allow air entry, the inclined section in between permits sufficient extension of the venturi tube for discharging the gas-air mixture.

[0018] Preferably, the lower mouth of the rim has a broad conical shape. This conical shape of the inner wall of the rim forming the air inlet channel directs incoming air toward the mixing chamber, while the inclined outer wall diverts any liquid poured onto it away from the mixing chamber.

[0019] Preferably, multiple integrated bridge elements are provided between the inner wall of the rim and the venturi tube. These bridge elements maintain the structural integrity of the upper part with its inner channel when it is produced as a one-piece metal injection-molded component. Thus, the desired dimensional accuracy can be achieved in production.

[0020] BRIEF DESCRIPTION OF THE FIGURES

[0021] Figure 1 is a top view of a gas hob, on which a representative configuration of the burner according to the invention is mounted.

[0022] Figure 2 is an exploded view of a representative configuration of the burner according to the invention.

[0023] Figure 3 is a top perspective view of the upper part of the burner shown in Figure 2.

[0024] Figure 4 is a bottom perspective view of the upper part. DETAILED DESCRIPTION OF THE INVENTION

[0025] In this detailed description, the improvement forming the subject matter of the invention is explained with references to examples for the sole purpose of better illustrating the subject matter, without imposing any limitation.

[0026] Figure 1 shows a hob, with its flat upper cooktop (1), on which four burners are arranged in a top view. The hob is a domestic appliance with rotary control knobs located near its front edge. The upper part (10) of the burner according to the invention is visible on the cooktop. Figure 2 provides an exploded view of the burner.

[0027] A lower part (40) is a metal, open-topped piece that surrounds a mixing chamber (42) in a bowl shape at its center. On the edge of the lower part (40), there are clip extensions onto which thermoelectric functional elements are mounted. Combustible gas is supplied to the mixing chamber (42) via an injector (2) that extends vertically in the middle of the base. A flat, metal mounting collar (30) is disposed on top of the lower part (40), encircling the open mouth of the mixing chamber (42). From its upper side, the mounting collar (30) accommodates the upper part (10), which can be removed from the lower part (40).

[0028] The upper part (10) has a circular, one-piece metal cover structure with an H-shaped cross section. The radially outer portion of the upper part (10) extends upward and forms a flame crown (14) having teeth (15) arranged in a circular pattern with gaps between them, and extends downward in the opposite direction in a widening incline to form a rim (12). Inside the upper part (10), there is a circular disk-shaped intermediate plate (16) extending inward from the outer wall. A circular opening at the center of the intermediate plate (16) constitutes the upper end of a venturi tube (17) and opens into the mixing chamber (42).

[0029] Figure 3 shows a top perspective view of the upper part (10). As seen here, the flame crown

[0030] (14) with teeth (15) arranged radially around its outer perimeter has a radial thickness, with the gaps between the teeth (15) forming flow channels that direct the gas-air mixture. By placing a disc-shaped flat upper cap (20) (shown in Figure 2) removably on top of the teeth

[0031] (15), these channels between the teeth (15) are covered from above, and the gas-air mixture is directed radially outward through the flame crown (14).

[0032] The intermediate plate (16) is stepped in two levels, with the upper end of the venturi tube (17) positioned at the higher level and the flame crown (14) at the lower level. Figure 4 shows a bottom perspective view of the upper part. The venturi tube (17) is a short cylindrical structure extending inward from the opening in the intermediate plate (16). A number of bridge elements (18) extend radially as rods from the outer wall of the venturi tube (17) to the inner wall of the rim (12).

[0033] Figure 5 shows a cross section taken through the center of the upper part (10). In the metal, one-piece upper part (10), an inverted V-like inner channel (11) having a flattened top is formed in the area where the rim (12) meets the intermediate plate (16) and extends into the flame crown (14). The upper portion of the inner channel (11) narrows toward the base of the tooth (15) and into the interior of the tooth (15) so that sufficient thickness remains to prevent gas leakage. Thus, when the upper part (10) is disposed on the lower part (40) in a manner that covers the mixing chamber (42) from above, the inner channel (11 ) delimits the upper edge of the mixing chamber (42). By removing material in the volume defined by the inner channel (11 ) relative to a standard burner design with a vertical injector, the burner is made lighter. Here, the radial inner wall (13) forming one adjacent inner corner of the inner channel (11) merges with the lower step of the flat intermediate plate (16). From the radial inner portion of the lower step, it merges upward through an inclined section to meet the step that extends radially outward from the upper edge of the venturi tube (17). The adjacent outer corner of the inner channel (11) merges with the inner wall of the rim (12) via a radial outer step. The angle between the inner channel (11) and the intermediate plate (16) is greater than the angle between the rim (12) and the intermediate plate (16).

[0034] By using this geometry, when the upper part (10) is disposed on the lower part (40), air flows from the corridor formed between the inner wall of the rim (12) and the outer wall of the lower part (40) through the air inlet opening into the mixing chamber (42) and mixes with the combustible gas supplied by the injector (2). It has been found that the combustion efficiency of this arrangement is higher than in a burner of similar design without the inner channel (11 ). In air-fuel mixtures, the AFR (Air Fuel Ratio) value is known as the equivalence ratio, expressing the ratio of the fuel-air mixture to the stoichiometric value. When this value is greater than 1 , the mixture is rich in fuel; when it is less than 1 , the mixture is lean (i.e., the air amount is greater). When it is equal to 1 , stoichiometric combustion occurs. A richer fuel mixture allows more fuel molecules to participate in the combustion reaction. The increased fuel amount leads to greater energy release during combustion and causes the temperature in the combustion region to rise, as more heat is generated. These results indicate that the invention could potentially increase combustion efficiency and also allow a more efficient energy conversion by elevating temperature levels in the combustion zone. In this invention, it has been observed that the fuel equivalence ratio is increased, that the formation of the channel results in less air entering the burner’s mixing chamber, and therefore the AFR value increases. A disproportionately large increase (for example, by 400- 500%) lengthens the flame. Improved burner efficiency allows foods being cooked to be done in a shorter time.

[0035] REFERENCE NUMERALS

[0036] 1 Upper cooktop 16 Intermediate plate

[0037] 2 Injector 17 Venturi tube

[0038] 10 Upper part 18 Bridge element

[0039] 11 Inner channel 20 Upper cap

[0040] 12 Rim 30 Mounting collar

[0041] 13 Radial inner wall 40 Lower part

[0042] 14 Flame crown 42 Mixing chamber

[0043] 15 Tooth

Claims

CLAIMS1. A burner for a hob, comprising, a lower part (40) surrounding a mixing chamber (42) in the form of a bowl, an intermediate plate (16) that sits on top of the mouth of the mixing chamber (42) and having a vertical venturi tube (17) extending into the mixing chamber (42) at its center, an upper part (10) having a rim (12) extending downward from the outer periphery of the intermediate plate (16) and a flame crown (14) extending upward in the opposite direction, formed by a plurality of spaced teeth (15), a flat upper cap (20) that covers the flame crown (14) from above, characterized in that the burner includes an inner channel (11 ) arranged such that, when it is disposed on the intermediate plate (16), it enters the upper part (10) from the inner corner of the rim (12) in a manner that increases the volume of the mixing chamber (42).

2. A burner according to claim 1 , wherein the rim (12) of the upper part (10) surrounds the lower part (40) at a radial distance.

3. A burner according to any of the preceding claims, wherein the inner channel (11 ) is configured such that its lower end enters the flame crown (14).

4. A burner according to claim 3, wherein the inner channel (11) has a continuous circular form.

5. A burner according to any of the preceding claims, wherein the inner channel (11 ) has a V-like cross-sectional shape.

6. A burner according to any of the preceding claims, wherein the lower end of the inner channel (11 ) is aligned with the venturi tube (17), while its opposite upper end is aligned above the upper edge of the venturi tube (17).

7. A burner according to any of the preceding claims, wherein a mounting collar (30) is disposed in a sealed manner between the upper part (10) and the lower part (40) and having a form suitable for connection to an upper cooktop (1).

8. A burner according to any of the preceding claims, wherein the upper part (10) and the lower part (40) are concentric and made of metal.

9. A burner according to any of the preceding claims, wherein an angled step form is provided between the upper inner corner of the rim (12) and the inner channel (11).

10. A burner according to any of the preceding claims, wherein the intermediate plate (16) includes a flat, planar section extending radially from the upper corner of the venturi tube (17), an inclined section extending downward at an angle from the outer periphery of the flat section, and a further flat, planar section extending from the outer periphery of the inclined section that connects to one end of the inner channel (11 ).

11. A burner according to any of the preceding claims, wherein the lower mouth of the rim (12) has a broad conical shape.

12. A burner according to any of the preceding claims, wherein multiple integrated bridge elements (18) extending between the inner wall of the rim (12) and the venturi tube (17) are provided.

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