ES2694766T3 - Burner unit and gas hob - Google Patents

Abstract

Burner unit (7) for a gas cooktop (1), said burner unit (7) comprising: - a gas distribution chamber (16) that can be connected to a gas supply system (30) for the cooking plate (1), said gas distribution chamber (16) being covered by a burner plate (13) defining the gas outlet holes (14), - an air distribution chamber (17) separated from the gas distribution chamber (16) and that can be connected to a forced ventilation group (11) of the cooking plate (1), the air distribution chamber (17) being covered by a diffuser (41 ) of air that at least partially defines one or more air outlet openings (36) separated from the gas outlet openings (14), in which the air diffuser (41) is mushroom-shaped and comprises an upper portion (43) defining at least partially the air outlet openings (36) and a positioning stem (44) projecting from the portion upper part (43) to the air distribution chamber (17) and which is received through a form coupling in a diffuser seat (45) formed in a lower wall (40) of the distribution chamber (17) of air opposite the air outlet openings (36), characterized in that the upper portion (43) of said air diffuser (41) has a lower surface (47) oriented towards the interior of the air distribution chamber (17). air and resting on a radially inner edge of the burner plate (13) to jointly define the air openings (36) in a region radially closer to an axis (46) of the stem (44) with respect to the holes Gas outlet (14), and because said lower surface (47) of the air diffuser (41) is inclined to direct a second air flow coming from the forced ventilation group radially outward and upward away from the unit ( 7) of burner to meet the flames at a certain distance from the hole s (14) gas outlet.

Description

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DESCRIPTION

Burner unit and gas hob

The present invention relates to a burner unit and a domestic gas cooking plate.

As is known, a gas cooking plate comprises a support and containment structure having an upper wall with a visible surface facing upward, a support grid disposed on the visible surface defining a plane on which the containers rest for heating, for example, pans, and one or more combustible gas burners configured to generate a series of flames in the gap between the visible surface and the support plane for heating the containers supported by the support grid.

Known gas cooktop burners generally comprise a main gas supply conduit which can be connected to an external source of combustible gas, for example, to the gas supply network or to a gas cylinder. One or more burner units are connected to the main conduit through one or more partial gas conduits, respectively. Each of the partial gas conduits has an associated adjusting valve (generally referred to as a gas tap), which is configured to adjust the gas passage through the partial conduit between a closed position and a maximum open position. In addition to the adjustment valve, there is a safety valve to interrupt the passage of gas through the partial conduit in response to a signal indicating irregular operation of the burner unit. A safety valve of this type can be arranged upstream or downstream of the adjusting valve (with reference to the direction of gas flow from the main conduit to the burner unit) or be integrated into the body of the adjustment valve .

In known domestic gas cooking plates, the burner is a non-aerated burner or also an atmospheric air burner (called an induced air burner), in which there is a venturi tube mixer disposed in the partial conduit upstream of the burner unit and suitable for sucking a quantity of primary air in the partial gas flow. For an efficient combustion, it is necessary that there is an additional volume of secondary air that is extracted by the flames themselves in the gap between the support plane (bottom of the pan) and the visible surface of the upper wall.

To obtain the most complete combustion possible, it is necessary to have a large amount of secondary air and, therefore, a hollow of this type must have a minimum free height (currently about 35 mm) to comply with emission reduction standards , in particular CO and CO2. Accordingly, the prior art baking plates are undesirably bulky and do not meet the needs of users who are increasingly aware of environmental sustainability, the impact on health and the design of their appliances and furniture.

European patent application EP 2072901 A discloses a domestic gas cooking plate with an upper wall having a visible surface, a burner unit arranged in the upper wall and configured to generate flames in the space between the visible surface and a plane of the pan support, a gas supply system configured to feed a gas flow to the burner unit, as well as a forced suction group suitable for sucking up a secondary air volume and feeding it to the burner unit.

It is also known from document FR 2618881 A2 a burner unit and a gas cooking plate. Although a known solution of this type allows a drastic reduction of CO and CO2 emissions and a reduction of the distance between the support plane (bottom of the pan) and the visible surface to allow innovative design solutions, the flame itself can be unstable and the small relative movements of the individual components of the burner unit may cause effects of flame instability.

The purpose of the present invention is, therefore, to provide a burner unit and a domestic gas cooking plate, having features such as to obviate at least some of the drawbacks cited with reference to the prior art.

In the main purpose, a particular purpose of the present invention is to propose a burner unit and a domestic gas cooking plate that guarantees a high flame stability and a reliable and accurate supply of air secondary to the flame itself.

A further purpose of the present invention is to configure the burner unit and the hob so that, under operating conditions, the burner unit and the system for supplying secondary air are always completely and correctly assembled.

These and other purposes are achieved through a burner unit according to claim 1 and through a domestic gas cooking plate according to claim 11.

Advantageous embodiments are the object of the dependent claims.

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In order to better understand the present invention and appreciate its advantages, some embodiments thereof will now be described as an example and not for limiting purposes, with reference to the accompanying figures, in which:

Figure 1 is a perspective view of a gas cooking plate according to an embodiment of the invention;

Figure 2 is a horizontal sectional view of the cooking plate in Figure 1;

Figure 3 is a sectional view of a part of a cooking plate according to an embodiment;

Figure 4 is a perspective cut-away view of a burner unit of the cooking plate in Figure 3;

Figures 5A-5C illustrate a component of the cooking plate in a side view, a perspective view and from above, respectively;

Figure 5D is a sectional view according to the line V-V in Figure 5B.

With reference to the figures, a domestic gas cooking plate is fully indicated with the reference number 1. The cooking plate 1 comprises a support and containment structure 2 with an upper wall 3 having a visible surface 4. In the upper wall 3 there is one or more support members 5 that support the containers to be heated, for example, pans, pots, coffee makers, etc., and define a support plane 6 on the side of the visible surface 4 of the upper wall 3 One or more burner units 7 are arranged in the upper wall 3, preferably partially projecting and partially inserted in said upper wall. The burner units 7 are configured to generate flames in a space 8 between the visible surface 4 and the support plane 6 which during use corresponds to the plane of the bottom part of the pan. The gas cooking plate 1 also comprises a gas supply system 30 supported by the support and containment structure 2 and configured to be able to feed a gas flow 34 possibly premixed with primary air 35 (figure 3) to the unit 7 of burner.

The gas cooking plate also comprises a forced ventilation group with an electric fan 9 suitable for sucking a secondary air volume 10 through a suction opening formed in the support and containment structure 2 and for transporting said secondary air 10. in a ventilation duct 11 extending in the supporting structure 2 (at least partially, preferably completely) below the visible surface 4. In other words, the ventilation duct 11 preferably extends to a lower side 12 of the wall upper 3 opposite the visible surface 4.

The ventilation duct 11 connects the electric fan 9 with the burner unit 7 in order to be able to feed the volume of the secondary air 10 to the latter.

The support members 5 can be formed in one piece with the top wall 3 which can preferably be made of cast iron or stainless steel.

Part of the burner unit 7 can also be formed in one piece with the top wall 3.

According to one embodiment, part of the burner unit 7 or the whole burner unit 7 can be made as a preassembled group (figure 4) initially separated from the top wall 3 and then connected thereto, and possibly a material different from the material of the upper wall 3, in particular aluminum.

The burner unit 7 comprises a burner plate 13 with a substantially annular shape defining a plurality of gas outlet holes 14 and a base portion 15 forming a gas distribution chamber 16 in communication with the system 30. of gas supply and with the gas outlet holes 14, as well as an air distribution chamber 17 separated from the gas distribution chamber 16 and in communication with the ventilation duct 11 and with one or more air openings 36 separated and separated from the gas outlet openings 14.

According to one embodiment, the gas distribution chamber 16 has an annular shape bounded from above by the burner plate 13 with the gas outlet holes 14, on the side by an outer circumferential wall 37 equipped with a side opening 38. to connect with the gas supply system 30 and by an inner tubular wall 39, as well as from below by a lower wall 40 opposite the burner plate 13.

The air distribution chamber 17 can be formed within the gas distribution chamber 16 and, preferably, coaxial with the latter. In particular, the air distribution chamber 17 is delimited from above by an air diffuser 41 that defines at least partially the openings 36 of air, on the side by the tubular wall 39 and from below by the lower wall 40 opposite to the openings 36 of air.

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Advantageously, the lower wall 40 forms one or more holes 42 for the entry of secondary air into the air distribution chamber 17.

According to an important aspect of the present invention, the air diffuser 41 has an upper portion 43 which, alone or preferably together with the burner plate 13, defines the aforementioned air openings 36, as well as a shank 44 of positioning projecting from the upper portion 43 in the air distribution chamber 17 and which is received through the shape coupling in a diffuser seat 45 formed in the lower wall 40.

This guarantees a safe, precise and reliable positioning of the air diffuser 41 and, therefore, a correct and homogeneous secondary air flow towards the flame.

According to one embodiment, the positioning rod 44 and the diffuser seat 45 make a sliding coupling along a single axis 46 through the mutual insertion, preferably along an axis 46 which is concentric and, preferably , substantially coaxial with symmetry axes of the air and gas distribution chambers 17, 16. In particular, the diffuser seat 45 forms a hole suitable for receiving a free end of the positioning rod 44, but allows its removal to facilitate cleaning or maintenance of the burner unit.

The air diffuser 41 is mushroom shaped and the upper portion 43 has a lower surface 47 facing inwardly of the air distribution chamber 17 and resting on a radially inner edge of the burner plate 13 to define, together with the latter, the aforementioned air openings 36. The lower surface 47 of the air diffuser 41 is inclined to direct the secondary air flow radially outwards and upwards (in other words, towards the support plane 6) to meet the flames at a distance from the exit holes 14 Of gas.

Advantageously, the burner plate 13 forms an annular projection 48 or a projection formed by the sections extending along a circle between the gas outlet holes 14 and the air openings 36, for diverting the secondary air flow (waters down the air openings 36) upwards in the area of the flame.

According to an embodiment, at least one burner unit 7 comprises a bearing reducer 49, for example, a cross-shaped frame, for example made of cast iron or stainless steel, which can be positioned on the burner plate 13 to make a support plane for small pans, for example with diameters of less than 120 mm. Said support reducer 49 is advantageously connected to the upper portion 43 of the air diffuser 41. In this way, the removal of the support reducer 49 from the burner unit 7 makes the burner unit unusable, which guarantees a correct and complete assembly (and the presence of the support reducer) of the hob under conditions of operation.

For the connection between the air diffuser 41 and the support reducer 49, the upper portion 43 has a hole 51 for receiving a connecting screw and the positioning stem 44 has an open tubular portion 50 to facilitate access to the screw through of a screwdriver.

The gas supply system 30 of the cooking plate 1 comprises a main conduit 31 for the supply of gas which can be connected to an external source of combustible gas. One or more partial conduits 32 connect the main conduit 31 to each of the burner units 7 and an adjustment valve 33 associated with the partial conduit 32 allows adjustment, preferably continuous, of the gas passage through the partial conduit 32 between a closed position and a maximum opening position.

As already mentioned above, in the partial duct 32 there can be air supply means configured so that, during operation, the gas flow 34 in the partial duct extracts a first volume of primary combustion air 35. The means of supply air, for example, comprise a venturi tube device 52 with a passage for the gas having a section with regulated section and one or more passages for the primary air 35 which opens near the portion with regulated section, so that the gas acts as an actuator fluid to bring the volume of primary air to the partial flow 34 of gas.

In the case in which the aforementioned primary air supply means are provided, the forced suction group 9 is advantageously configured to suck the secondary air 10 from a different area of the primary air suction area.

A control unit 53 controls the forced suction group 9 in response to an actuation of the adjustment valve 33, to activate the forced flow of secondary air at the same time gas is fed to the burner unit 7.

The domestic gas cooking plate 1 has numerous advantages. Thanks to the configuration of the air diffuser and its positioning through the shape connection in the lower part of the burner unit, the air flow

secondary is distributed homogeneously and is transmitted accurately and reliably to the flame. In this way it is ensured that there is a high stability of the flame even in the case of large reductions in the height of the space 8 between the visible surface 4 and the bottom of the pan.

5 The high stability of the flame in turn contributes to a more complete combustion, as well as to a reduction of CO and CO2 emissions for the same thermal power of the burner unit.

Of course, one skilled in the art can provide modifications and additional variants to the burner unit and the domestic gas cooking plate in accordance with the present invention, in order to meet specific and contingent requirements, all of which are covered in any case by the scope of protection of the invention, as defined in the following claims.

Claims (12)

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Five fifty 55 60 65 1. - Burner unit (7) for a gas cooking plate (1), said burner unit (7) comprising: - a gas distribution chamber (16) that can be connected to a gas supply system (30) for the cooking plate (1), said gas distribution chamber (16) being covered by a plate (13) of burner defining the gas outlet holes (14), - a chamber (17) for air distribution separated from the gas distribution chamber (16) and which can be connected to a forced ventilation group (11) of the cooking plate (1), the chamber (17) of air distribution being covered by an air diffuser (41) defining at least partially one or more air outlet openings (36) separated from the gas outlet openings (14), wherein the air diffuser (41) is mushroom-shaped and comprises an upper portion (43) that at least partially defines the air outlet openings (36) and a positioning stem (44) projecting from the portion upper (43) to the air distribution chamber (17) and received through a shape coupling in a diffuser seat (45) formed in a lower wall (40) of the distribution chamber (17) air opposite the air outlet openings (36), characterized in that the upper portion (43) of said air diffuser (41) has a lower surface (47) facing inwardly of the air distribution chamber (17) and resting on a radially inner edge of the plate ( 13) to jointly define the air openings (36) in a region radially closer to an axis (46) of the stem (44) with respect to the gas outlet holes (14), and in that said lower surface (47) of the air diffuser (41) is inclined to direct a second air flow coming from the forced ventilation group radially outward and upwardly away from the burner unit (7) to meet the flames at a certain distance from the gas outlet holes (14). 2. - Burner unit (7) according to claim 1, wherein the gas distribution chamber (16) has an annular shape defined by said burner plate (13), by an outer circumferential wall (37) equipped with a side opening (38) for connection to the gas supply system (30), by an internal tubular wall (39), as well as by a lower wall (40) opposite the burner plate (13), wherein the air distribution chamber (17) is formed within the gas distribution chamber (16) and is defined by said air diffuser (41), the tubular wall (39) and the lower wall (39). 40) opposite the air openings (36), wherein said lower wall (40) forms one or more holes (42) for communication of the air distribution chamber (17) with the ventilation group (11) forced 3. - Burner unit (7) according to any of the preceding claims, wherein said positioning rod (44) and the diffuser seat (45) form a sliding coupling along a single axis (46) through mutual insertion. 4. - Burner unit (7) according to the preceding claim, wherein said shaft (46) is concentric with the air and gas distribution chambers (17, 16). 5. - Burner unit (7) according to any of the preceding claims, wherein the diffuser seat (45) forms a hole suitable for removably receiving a free end of the positioning rod (44). 6. - Burner unit (7) according to any of the preceding claims, comprising an annular projection (48) between the gas outlet holes (14) and the air openings (36). 7. - Burner unit (7) according to any of the preceding claims, comprising a support reducer (49) that can be positioned above the burner plate (13) to make a support plane for small pans, said support reducer (49) connected with the upper portion (43) of the air diffuser (41). 8. - Burner unit (7) according to the preceding claim, wherein the upper portion (43) of the air diffuser (41) forms a hole (51) that receives a connecting screw and the stem (44) of positioning forms an open tubular portion (50) to facilitate access to the screw. 9. - Burner unit (7) according to any of the preceding claims, wherein the entire burner unit (7) is realized as a preassembled group that can be connected to an upper wall (3) of the plate ( 1) cooking. 10. - Burner unit (7) according to any of the preceding claims, wherein the burner unit (7) is made substantially of aluminum. 11. - Domestic gas cooking plate (1) comprising: 5 - one or more burner units (7) according to any of the preceding claims, - a gas supply system (30, 31, 32, 33) configured to feed a gas flow (34) to said burner unit (7), 10 - a group (9, 11) of forced ventilation suitable to suck up a secondary volume of air (10) and feed said flow (10) of secondary air to said burner unit (7). 12. - Domestic gas cooking plate (1), comprising: fifteen - a support and containment structure (2) with an upper wall (3) having a visible surface (4), - one or more support members (5) arranged in said upper wall (3) and defining a support plane (6) for the containers to be heated, said support plane (6) being on the side of the visible surface ( 4) of the wall 20 upper (3), wherein said unit or more burner units (7) are arranged in said upper wall (3) and configured to generate flames in the space (8) between said visible surface (4) and said support plane (6).