EP3268667B1

EP3268667B1 - Improved gas burner

Info

Publication number: EP3268667B1
Application number: EP16718457.1A
Authority: EP
Inventors: Girolamo Tommaso Emiliani; Luca BRECCIA
Original assignee: EGO Elektro Geratebau GmbH
Current assignee: EGO Elektro Geratebau GmbH
Priority date: 2015-03-10
Filing date: 2016-03-09
Publication date: 2020-11-18
Anticipated expiration: 2036-03-09
Also published as: RU2017130719A3; BR112017019156A2; WO2016142872A1; EP3268667A1; RU2017130719A; RU2701432C2; ES2854279T3; MX2017011520A

Description

The present invention relates to an improved gas burner.
Single control gas burners with multiple concentric flame rings are known, i.e. burners in which the gas feed is controlled by a single tap. These generally comprise an injector holder cup, a flame divider resting on the injector holder cup and formed from two parts joined together to define an inner central chamber and an outer annular chamber, a discoidal cover which upperly bounds the central chamber of the flame divider, and an annular cover which upperly bounds the annular chamber of the flame divider.
Hence, known gas burners with multiple concentric rings are formed from a total of five elements assembled together, their production cost therefore being fairly high.
One of these known burners is described for example in EP 797048 , which comprises five elements: a lower cup-shaped support, an intermediate cylindrical element, a head comprising an inner circular chamber and an outer annular chamber, and two closure covers for said chambers.
To reduce production cost and lessen their assembly complexity, gas burners with multiple flame rings have been proposed, formed from four or three elements.
For example, EP 2572141 describes a gas burner with multiple flame rings comprising an injector holder and a flame divider defining an outer annular chamber and an inner circular chamber, both closed upperly by a single cover. The injector holder comprises two cup-shaped supports and two vertical injectors positioned in a diametrical plane and facing two vertical conduits, which are defined within the flame divider and open upperly into respective arched radial chambers of venturi effect defined in the outer annular chamber. In addition, each arched chamber is fluidically connected to the burner inner chamber via two radial channels.
In greater detail, in this burner, the gas feed conduit extends horizontally below the bottom of the two cups along their alignment direction, the two vertical injectors which feed gas to the two arched chambers being applied to it. However, the fact that one injector is closer to the gas inlet than the other means that most of the gas leaves from that injector which is the first to be encountered by the gas. It follows that a greater gas quantity reaches the arched chamber fed by the injector closer to the gas inlet, hence the corresponding flames leaving the ports of said chamber are more consistent than those leaving the ports of the other arched chamber. Essentially, in this burner, the generated flames are neither equal nor are they distributed uniformly along the entire circumference.
Furthermore, in this known burner the primary air is withdrawn always and exclusively from above the cooking hob.
EP1459012 discloses a burner comprising a cup piece and a flame divider element that rests on said cup piece and that consists of two parts (i.e. a Venturi tube and a hollow body) joined by connecting elements. The hollow body of the flame divider presents a central inner chamber closed by a circular plate, a first annular chamber closed by a first annular plate and a second annular chamber closed by a second annular plate. All these three plates are made of separate pieces. Moreover, the radial channels connecting the inner chamber to the first and second annular chambers are closed upperly by a wall of the body of the flame divider.
EP0797048 discloses a gas burner with a central portion and an annular portion that are upperly closed by two separate covers, respectively a first cover and a second cover that are located at different heights; indeed, the central portion is raised above the annular portion.
EP0903538 discloses a gas burner for gas cookers that comprises: a central flame crown concentric with two circumferential crowns themselves concentric; radial ducts for feeding the primary gas-air mixture to the circumferential crown and a substantially horizontal Venturi effect chamber defined by facing surfaces and equidistant from the body of the burner and from the cover of the central flame crown respectively. In the gas burner according to EP0903538 the intake of primary air is only and always from above the cooking hob.
EP0676591 relates to a domestic cooking hobs wherein generic burners can intake primary air from above or below the cooking hob.
An object of the invention is to provide a gas burner with only three components, and/or in any event a reduced number of components.
Another object of the invention is to provide a gas burner obtainable at very low production cost.
Another object of the invention is to provide a gas burner which is installable with extreme ease, rapidity and safety.
Another object of the invention is to provide a gas burner in which the flame distribution is uniform along its entire extension.
Another object of the invention is to provide a gas burner using injector holder cups in which the primary air is drawn in from below the cooking hob (such as those widespread in certain countries, such as Brazil).
These and other objects which will be apparent from the ensuing description are attained according to the invention by a gas burner with the characteristics of claim 1.
The present invention is further clarified hereinafter by means of some preferred embodiments thereof described by way of non-limiting example with reference to the accompanying drawings, in which:

Figure 1: is an exploded perspective view of an installation of the burner according to the invention, seen from above,
Figure 2: is an exploded perspective view thereof seen from below,
Figure 3: is a vertical section therethrough in the assembled configuration,
Figure 4: shows the flame divider of the burner of Figures 1-3 in plan view,
Figure 5: is a plan view showing a cover applicable to the flame divider of Figure 4,
Figure 6: is a plan view showing a different embodiment of the flame divider of the burner according to the invention.
Figure 7: is a plan view showing a cover applicable to the flame divider both of Figure 4 and of Figure 6.

As can be seen from the figures, the burner 2 according to the invention comprises a flame divider 4, installable on an injector holder 6, and a cover 8.
In particular, the injector holder 6 is of traditional type and adheres from below to the sheet metal of a cooking hob 10 to which the burner is intended to be fixed by screws. Advantageously, the injector holder 6 can also pertain to a different burner which had been previously mounted on the cooking hob 10, so making its installation particularly easy for the user.
According to the installation represented in Figures 1-3, the injector holder 6 comprises a dish 12 provided with lateral apertures 13 for entry of primary air withdrawn from below the cooking hob. In greater detail, the lateral wall of the dish 12 is provided with a flange 14 projecting outwards, to adhere to the sheet metal of the cooking hob 10 from below. Moreover, said lateral wall extends above the flange 14 to define a collar 15 on which the flame divider 4 rests and is supported.
The injector holder 6 with dish 12 is particularly advantageous as it is small and compact, and moreover, by drawing the primary air from below the cooking hob 10, it does not require large dimensions to increase the burner power.
In the described installation, the injector holder 6 comprises a gas feed conduit 20. It extends horizontally below the bottom of the dish 12 of the injector holder 6, it is open at one end 21 for air entry, and communicates with a vertical injector 22 screwed centrally to the base of the injector holder.
The installation represented in Figures 1-3 is configured to restingly receive the flame divider 4.
The flame divider 4 comprises an outer chamber 26 of overall annular shape, and an inner chamber 28 of overall circular shape, between which at least one cavity 29 is defined.
A tubular conduit 30 extends downwards from the inner chamber 28 of the flame divider 4 and is inserted into the collar 15 of the dish 12 until the upper edge of said collar 15 abuts against the lower surface 27 of the flange surrounding the tubular conduit 30. In greater detail, this contact between the upper edge of the collar 15 and the lower surface of the flange 27 which surrounds the tubular conduit 30 of the flame divider 4 defines a sealed closure which prevents primary air from entering the dish 12 from above the cooking hob. In the case of installation of the flame divider 4 on an injector holder 6 with dish 12, centring is suitably ensured by the insertion of the tubular part 30 of the flame divider 4 into the collar 15 of the injector holder 6.
In addition, downwardly extending shaped projections 23 are provided on the lower surface of the flange 27 of the flame divider 4.
The manner in which the flame divider 4 rests on the injector holder 6 is such that the flame divider is spaced from the sheet metal 10 of the cooking hob to such an extent as to determine passages therewith for the secondary air 25 intended for the flames which emerge from the cavity 29 of the flame divider 4.
More particularly, the outer annular chamber 26 of the flame divider 4 presents an outer wall 32 which extends along a cylindrical surface, and an inner wall 34, a certain part of which extends concentrically to the outer wall 32, but then connects to parts substantially radial to the cylindrical wall 35 of the inner chamber 28.
Advantageously, second shaped projections 39 are provided on the lower surface of the outer annular chamber 26 to prevent unbalance, disequilibrium or incorrect positioning of the flame divider 4 in the case of involuntary contacts thereof.
In a first embodiment of the flame divider 4 (see Figures 1 and 4), the outer annular chamber 26 of the flame divider 4 is connected fluidically to the inner chamber 28 via two substantially radial channels 36 (diametrically aligned) which divide the space between the outer annular chamber 26 and the inner circular chamber 28 into two symmetrical cavities 29. In addition, the outer annular chamber 26 is divided into two arched sectors 39 separated from each other by two diametrically opposite passages 41 forming two inter-ignition channels between the inner cavities 29 of the flame divider 4 and the outside.
In a second embodiment of the flame divider 4 (see Figure 6), the outer annular chamber 26 is connected fluidically to the inner circular chamber 28 via four substantially radial channels 36 (disposed substantially at 90° apart), which divide the space between the outer annular chamber 26 and the inner circular chamber 28 into four equal cavities 29.
In addition, the outer annular chamber 26 is divided into four sectors 39 separated from each other by four passages 41 forming four inter-ignition channels.
In an embodiment not shown herein, the outer annular chamber 26 and the inner circular chamber 28 of the flame divider 4 are fluidically connected together by a single channel 36. In this case, there is a single cavity 29, which surrounds the inner circular chamber 28, and a single inter-ignition channel 41.
In greater detail, in both the represented embodiments of the flame divider 4. the outer annular chamber 26 and the inner circular chamber 28 are bounded by a single continuous wall which is provided, along its entire extension with the exception of the parts relative to the radial channel or channels 36, with a plurality of ports for the exit of the primary gas/air mixture and the generation of at least two flame rings. Said ports suitably comprise main ports 42 and secondary ports 43 (see Figures 1 and 2).
Preferably, said ports 42 and 43 are defined in the outer wall 32 of the outer annular chamber 26, to generate a first ring of outward directed flames, in the inner wall 34 of the outer annular chamber 26, to generate an intermediate second ring of flames which open into the cavity 29, and in the lateral wall 35 of the inner chamber 28, to generate an internal third ring of flames which also open into the cavity 29.
In further embodiments of the present invention, not shown herein, only two flame rings can be provided, one fed via the ports 42, 43 provided in the outer wall 32 of the outer annular chamber 26, and the other fed via the ports 42, 43 provided in the inner wall 34 of the outer annular chamber or, alternatively, provided in the lateral wall 35 of the inner circular chamber 28 of the flame divider 4.
The tubular conduit 30 of the flame divider 4 defines a vertical channel 46 the bottom of which faces the injector 22 mounted on the injector holder 6 and upperly opens into a radial chamber 47 of venturi effect, bounded circumferentially by the wall 35 of the inner chamber 28, bounded lowerly by a base 49, and bounded upperly by a cover 8, the position of which, relatively to the flame divider 4, is defined by four centring pegs 50 provided therein.
Preferably, curved bulkheads 37 carrying a central passage aperture are provided between the circumferential wall 35 of the inner chamber 28 and the upper end of the tubular conduit 30, to define arched under-chambers in cooperation with the circumferential wall 35. In particular, the mixture leaving the tubular conduit 30 enters the arched under-chambers via the passage aperture defined in the curved bulkheads 37, and emerges from these via the ports 42, 43 provided in the lateral wall 35 of the inner circular chamber 28 of the flame divider 4. In this manner, the mixture leaving the tubular conduit 30 is slowed down to prevent flame detachment and to provided greater stability to the main flame ring fed via the ports 42, 43 provided in the circumferential wall 35 of the inner circular chamber 28.
The cover 8 is made in one piece and comprises an outer annular portion 52, an inner discoidal portion 54 and four shaped radial portions 56 the purpose of which is to connect together the outer portion 52 and the inner portion 54 and to upperly close the channels 36 and/or the passages 41. In particular, in the cover represented in Figure 8, which is adapted to rest on the flame divider of Figures 1 and 4 , two diametrically aligned radial connection portions 56 are provided for upperly closing the two channels 36 of the flame divider 4. In contrast, in the cover of Figure 7 four shaped radial connection portions 56 are provided disposed at 90° to each other, to upperly close the four channels 36; this cover 8 is particularly adapted for resting on the four-channel flame divider of Figure 6, however it can also be suitably used in combination with the two-channel flame divider of Figure 4 (see Figures 1-2).
If a flame divider 4 with a single radial channel 36 is provided, the cover 8 can comprise a single radial portion 56 for connecting the inner discoidal portion 52 to the outer annular portion 56, to upperly close said radial channel 36.
The burner according to the invention operates in the following manner.
The gas entering through the inlet aperture 21 from the conduit 20 emerges from the injector 22 and enters the vertical conduit 46 of the flame divider 4, entraining with it the primary air drawn from below the cooking hob 10(see Figures 1-3).
The stream of gas and primary air which begins to mix within the vertical conduit 46 then completes its mixing in the corresponding radial venturi chamber 47, bounded upperly by the inner discoidal portion 54 of the cover 8.
The mixture obtained in this manner can thus feed the inner flame ring leaving the ports 42 of the inner circular chamber 28. In addition, the mixture propagates along the channels 36, closed upperly by the connecting portions 56 of the cover 8, to reach the outer annular chamber 26 of the flame divider 4 to feed the outer flame ring and, if provided, also the intermediate flame ring.
The injector holder 6 suitably comprises a support arm 60 for an ignition spark plug 62.
From the aforegoing it is apparent that the burner according to the invention is much more advantageous than traditional multi-flame ring burners, and in particular:

it is formed from only three pieces and, by virtue of the one-piece die-cast construction of the flame divider without secondary machining operations, is of extremely simple and economical production,
although intended for a two or three flame ring burner, the cover is also constructed in one piece, this also making the burner production extremely simple and economical,
it has a radial venturi-type mixing chamber, contributing to a reduction in the burner overall vertical height,
it has a single injector positioned at the centre of the injector holder, and this combined with the fact that the radial venturi effect chamber is defined in the inner circular portion of the flame divider, directly facing the injector, means that a single mixture is obtained which is uniformly distributed also within the outer annular chamber of the flame divider, to obtain the formation of rings of uniform flames along the respective circumferences,
the assembly of the three components (injector holder, flame divider and cover) is made particularly easy, quick and intuitive.

In particular, the burner according to the invention is different from and more advantageous than traditional burners in that, besides consisting of only three components (the injector holder, the flame divider and the cover), it presents at the same time a flame distribution which is uniform and homogeneous along its entire circumferential development.

Claims

A gas burner with at least two flame rings, consisting of:
- an injector holder (6) provided with a single vertical injector (22) positioned centrally on the base of said injector holder (6),

- a flame divider (4) with an outer chamber (26) of overall annular development, and an inner chamber (28) of overall circular development, between which an annular cavity (29) is interposed,

- a cover (8),
and in said gas burner:
- said flame divider (4) comprises on its lower part resting means (30, 23) of said flame divider on said injector holder (6, 12), and its connection thereto,

- the inner circular chamber (28) of said flame divider (4) comprises a single substantially vertical channel (46) facing said single vertical injector (22) of said injector holder (6), said substantially vertical conduit (46) opening into a radial chamber (47) of venturi effect defined in said inner chamber (28) of the flame divider (4) and upperly bounded by the central discoidal portion (54) of said cover (8),

- said flame divider (4) comprises at least one substantially radial channel (36) for fluidic connection between said inner circular chamber (28) and said outer annular chamber (26), said radial channel (36) being closed upperly by a corresponding radial part (56) of said cover (8),

- said at least two flame rings comprising a first ring of flames, generated at ports (42, 43) provided in the outer wall (32) of said outer annular chamber (26) of the flame divider (4), and at least one second ring of flames which can be generated at ports (42, 43) provided in the inner wall (34) of said outer annular chamber (26) of the flame divider (4), or at ports (42, 43) provided in the lateral wall (35) of said inner chamber (28) of the flame divider (4) or at ports (42, 43) provided in both the inner wall (34) of said outer annular chamber (26) and said lateral wall (35) of said inner circular chamber (28),

- said cover (8) is made in one piece and comprises a central discoidal portion (54), which upperly closes said inner circular chamber (28), and an annular portion (52) which upperly closes said outer annular chamber (26),

- said substantially vertical channel (46) facing said single vertical injector (22) is defined within a tubular conduit (30) which extends downwards from the inner chamber (28) of the flame divider (4),
and characterized in that:
- said injector holder (6, 12) is of dish shape and is provided with apertures (13) for the intake of primary air from below a cooking hob (10) in which said burner is to be installed, and in that said resting means (30, 23) comprise said tubular conduit (30), which is sealedly inserted into said dish shaped injector holder (6, 12).
A burner as claimed in claim 1, characterised in that:
- said apertures (13) for entry of primary air withdrawn from below the cooking hob (10) are provided laterally on the dish of said injector holder (6), lateral wall of the dish (12) being provided with a first flange (14) projecting outwards for adhering to the sheet metal of the cooking hob (10) from below, said lateral wall of the dish (12) extending above said first flange (14) to define a collar (15) on which the flame divider (4) rests and is supported,

- said tubular conduit (30) is inserted into the collar (15) of the dish (12) of the injector holder (6) until the upper edge of said collar (15) abuts against the lower surface (27) of a second flange surrounding the tubular conduit (30), thus defining by this contact a sealed closure which prevents primary air from entering the dish (12) of the injector holder (6) from above the cooking hob.
A burner as claimed in claim 1 or 2, characterised in that said tubular conduit (30) is dimensioned such as to adhere to the inner wall of an upper collar (15) provided in said dish shaped injector holder (6, 12), in such a manner as to hence define a sealed closure which prevents primary air from entering the dish shaped injector holder (6, 12) from above the cooking hob.
A burner as claimed in one or more of the preceding claims, characterised in that said resting means comprise:
- a tubular conduit (30), which extends downwards from the inner chamber (28) of the flame divider (4), and is sealedly inserted into said injector holder (6, 12) in the case in which said injector holder (6, 12) is shaped as a dish provided with apertures (13) for intake of primary air from below a cooking hob (10) in which said burner is intended to be installed,

- shaped projections (23) which project downwards from the base of the flame divider (4), and engage with said injector holder (6, 16) in the case in which said injector holder (6, 16) is shaped as a cup closed both laterally and at its base, in such a manner as to define apertures, for entry into the injector holder, of primary air (19) drawn from above the cooking hob (10) in which said burner is intended to be installed.
A burner as claimed in one or more of the preceding claims, characterised in that said flame divider (4) rests on said injector holder (6) by way of said resting means (30, 23) in such a manner as to be spaced from a cooking hob (10) to such an extent as to define, therewith, apertures for the entry, into said annular cavity (29), of secondary air (25) intended for said second flame ring.
A burner as claimed in one or more of the preceding claims, characterised in that at least one aperture (41) forming an inter-ignition channel is provided in said outer annular chamber (26).
A burner as claimed in one or more of the preceding claims, characterised in that said ports provided in the outer wall (32) of said outer annular chamber (26) of the flame divider (4) and/or in the inner wall (34) of said outer annular chamber (26) of the flame divider (4) and/or in the lateral wall (35) of said inner circular chamber (28) comprise main ports (42) and secondary ports (43).
A burner as claimed in one or more of the preceding claims, characterised in that said flame divider (4) comprises two radial channels (36) of fluidic connection between its inner circular chamber (28) and its outer annular chamber (26).
A burner as claimed in claim 8, characterised in that the walls which bound said radial channels (36) of the flame divider (4) comprise inter-ignition secondary ports for propagating the flames between said ring of flames generated at the ports (42, 43) provided in the inner wall (34) of said outer annular chamber (26) of the flame divider (4) and said ring of flames generated at the ports (42, 43) provided in the lateral wall (35) of said inner circular chamber (28) of the flame divider (4).
A burner as claimed in one or more of the preceding claims, characterised in that said injector holder (6) comprises an arm (60) for supporting an ignition spark plug (62) positioned in said annular cavity (29).