GB2272283A

GB2272283A - Super-slim gas safety burner

Info

Publication number: GB2272283A
Application number: GB9321795A
Authority: GB
Inventors: Aretxaga Inaki Ayastuy
Original assignee: Fagor Electrodomesticos SCL
Current assignee: Fagor Electrodomesticos SCL
Priority date: 1992-10-22
Filing date: 1993-10-22
Publication date: 1994-05-11
Also published as: FR2697320A1; GB9321795D0; FR2697320B3; ES2109119A1; ES2109119B1; IT1266611B1; ITMI932247A0; ITMI932247A1

Abstract

A gas safety burner comprises a pan-support (2), a body (3) and a head (4) and incorporates a sparking plug (14) and a safety flame-detecting thermocouple (15). The head (4) has two concavities forming with the body (3) the respective precincts (20, 21) housing the lighting electrode (14) and the sensitive thermocouple (15) point, which precincts have particular flame holes (23, 26) for lighting and controlled heating of such sensitive point, respectively. The holes (26) to the thermocouple are of a greater diameter than the holes (23) to the lighting electrode. The side walls of the concavity associated with the thermocouple are straight and outwardly divergent to expedite cooling of the thermocouple. The head is adjustably positioned on the body which is itself adjustably positioned on the pan-support. The pieces have centering, guiding and fixing elements for a fast and easy assembly after each cleaning. <IMAGE>

Description

SUPER-SLIH GAS SAFETY BURNER SPECIFICATION OBJECT OF THE INVENTION The invention relates to a super-slim atmospheric gas burner of the open kind, where the primary air is taken above the surface of the appliance and previously mixed in a chamber with the fuel gas at the injector outlet, and fitted with a sparking plug and a safety flame-detecting device. It is applicable to surface cooking appliances, in particular for households, both if they are super-slim or conventional.

BACKGROUND OF THE INVENTION The following are known: - A gas burner (Energietechnik 8 Jg. Heft 5, May 1958) with the primary air inlet above the worktop of the cooking appliance between a burner body and a supplemental burner.

- A gas burner (FR patent 2062094) having two openings to house a plug and a safety device at diametrically opposed peripheral positions, sheltered from spillage and external damage and comprising a head having two outlet hole formations at a different height, one being for the main flame and the other provided at the mouth of the pilot flame.

- A gas burner (Belgian patent 902,029) wherein the container-support defines a pre-mixing chamber opening downwards and the closed bottom of which houses the injector, fixed to the cooking appliance plate and an element or body covering the container-support having a central tubular portion defining a through hole with a vertical axis downwardly extending in the said chamber; this burner is difficult to assemble each time the burner is cleaned, for as the body piece has guide ridges the user must roughly direct the guide ridges on the body and then usually make several attempts at fitting the body into the respective channels in the container-support.

DESCRIPTION OF THE INVENTCON The super-slim gas burner subject of this invention has been designed for cooking worktops, in particular for households, requiring flame safety and fast lighting and starting, its design allowing burners to be constructed preferably having between 1 Kw and 4 Kw of heating power, its double gas inlet and little thickness allowing the same to be used in all kinds of appliances.

It is a fact that there is an increasing demand in the market of gas cooking appliances, and in respect of surface burners, for a reliable and durable flame safety device in order to prevent the leakage of fuel gas when not burnt, which device may moreover allow a fast and easy lighting of the gas, avoid waiting times frequent in worktop burners, which waiting times are due to the delay in responding of current heat-sensible safety devices in cooking appliances.

Furthermore, there is a safety requirement that these devices also take prompt action in the event of the flame being accidentally put out, sealing the inlet valve before too much gas accumulates on the worktop surface. Bearing in mind the need for a reduced safety cost in household cooking appliances, it is preferable for this kind of appliances to have the burner lighted by means of a spark and for the safety device to rely on a thermocouple to detect the presence of a flame. The imposed requirement of improving both response times of the safety device in respect of those that are currently required and to increase the duration thereof, causes the sparking plug and the flamedetecting thermocouple to be fitted in the burner as such, sheltered from any damage that might be caused to such devices through spillage, cleaning products and mechanical wear.

The burner subject of the invention, made with three basic compact pieces, a lower piece or pan-support, a middle piece or body and a top piece or head, meets the aforesaid market requirements, incorporating a sparking plug and a special safety flame-detecting thermocouple in diametrically opposed housings, making the head and the body so as to form two peripheral precincts housing the active points of the said devices and where they are protected by the head cover, the two precincts being provided from specific holes with different flames suitable for lighting and detection purposes, a first closed precinct linked with lighting having a crown on the inner face of the head that is coaxial with the plug to form a path making the electric arc inflaming the gas, and a second precinct that is open and linked to the thermocouple, open via a channel made on the peripheral edge of the body for a greater access of the cold air to the outside in order to speed up the cooling of the sensitive thermocouple point in the event of the flame being put out. For a limited heating of the thermocouple, preferably between 550 and 650 C two adjacent outlet holes are provided in the distributor, the flames of which flank the sensitive point of the said device, a high temperature limit imposed by the life duration and a low limit needed to hold the safety valve in the tap open.The making of the burner with only the said three basic pieces and duly providing structural guide and attachment elements in each such pieces, as shall be described hereinafter in full detail, offer the burner subject of the invention an additional advantage as compared with known burners, namely fast and easy assembly after each cleaning.

The pan-support has means for attachment with screws to the cooking appliance, lying under the worktable through the depth of which and projecting therefrom there are several inner radial ridges with their upper edges stepped. The top steps closest to the centre of the piece allow the user to centre the body directly on the pan-support, being guided in directing the same through the openings for the passage of the plug and the thermocouple and an additional guide-hole made on the flat portion thereof, the body then stably resting upon the surface of the lower steps of the ridges and fixed by fitting a guide-pin projecting from one of the ridges on the pan-support into such guide hole.

The head, through two 90 semicircular notches made on the lower edge of the vertical peripheral wall thereof, one on either side of the concavity associated to the thermocouple, accurately fits with the body by placing the said notches upon two elongate embossments of the body with the same semicircular profile as the former, which fit is easily made at a first attempt due to the prior orientation provided by the concavities on the vertical wall of the head associated to the plug and the thermocouple.

It has moreover been provided in accordance with another characteristic of the invention that the precinct associated to the lighting on the periphery of the burner, housing the plug, be configured in the burner between the head and the body, but so as not to affect the main flame, to which end the concavity is semicircular and has been made only on the thinnest portion of the annular wall distributing the pilot flame. To light the gas, pursuant to this configuration, it is provided that the spark shall fly between the electrode and the outer body of a horizontal section delimiting the upper portion of the precinct, which section of the annular wall of the head is swollen above this precinct.

The bore made in the body for the passage of the plug is located so far from the central shaft that it actually affects the peripheral projecting edge of the body, creating an opening of air in the precinct, and at the same time conditioning the flying of the spark towards the said edge on the head of the burner.

The precinct associated to the flame detector, housing the thermocouple, is configured in the proposed burner by means of a semicircular concavity made throughout the annular head wall, which therefore affects both flames, the main and the pilot flames, though a narrowing of the average thickness has been provided in order to enhance combustion, and at the same time allow a quicker cooling of the thermocouple after extinguishment, as was the case with the thick walls of the previously described embodiment.

To position the body on the pan-support and draw both portions apart to provide the necessary space for primary air to enter, it has also been provided that to replace the inner radial ridges mentioned hereinbefore, the horizontal peripheral platform of the pan-support be provided with four axially projecting wings, one per quadrant, which therefore leaves the fuel mixing change free from obstacles to be cleaned.

DESCRIPTION OF THE DRAWINGS In order to provide a fuller description and contribute to the complete understanding of the characteristics of this invention, a set of drawings is attached to the specification which, while purely illustrative and not fully comprehensive, shows the following: Figure 1.- Shows the burner as a whole assembled, as a vertical section along the diameter joining the plug and thermocouple housings.

Figure 2.- Is a top plan view of the burner body.

Figure 3.- Is a top plan view of the pan-support of the burner.

Figure 4.- Is a section of the pan-support along plane A-A of figure 3, showing the a close-view of its fit with the body.

Figure 5.- Is an elevation view of the burner head, showing the peripheral profile cut away.

Figure 6. - Is a section of the head along plane B-B of figure 5.

Figure 7.- Again shows the burner as a whole assembled, as a vertical section similar to that of figure 1, but in accordance with the different embodiment which includes the aforesaid alternatives.

Figure 7b.- Is a partial vertical section of the burner crossing the flame detector.

Figure 8.- Shows the burner body as a vertical section crossing the thermocouple.

Figure 8b.- Is partial vertical section of the body showing the bore for the plug.

Figure 9.- Is a profile of the burner head.

Figure 10.- Is a horizontal section of the head at the height of the main flame holes.

Figure 11.- Is a horizontal section of the head at the height of the pilot flame holes.

Figure 12.- Is a top view of the burner pan.

Figure 13.- Is a vertical section of the pan-support crossing the hole holding the plug and a spacing wing.

PPFFEEEED FMRODIMENT OF THE INVENTION A preferred embodiment of the aforesaid gas burner (1) and shown as a vertical section in figure 1, essentially comprises a pan-support (2), a body (3) and a head (4), fitted with a sparking plug (14) and a safety thermocouple (15).

The pan-support (2) shown in figures 3 and 4 is the gasprimary air premixing chamber (5), holding and guiding the body; it is structurally provided with several angularly distributed inner radial ridges (37) of uniform thickness, starting from the inner face of the side wall (38) and having a limited radial length to allow the housing of the hollow central organ (7) of the body, projecting above the surface (6) where the pan-support is attached, the latter having on its top edge a height stepping, where the higher steps (39), closest to the central axis of the piece, allow a first centering of the body on the pan-support and the lower steps (40), taking up the larger portion of the radial length of the ridge, allowing a stable support of the body, drawing the same away from the cooking worktop tray to delimit the clearance (41) for the inlet of outer primary air into the burner.At least one of the radial ridges (39) of the pan-support has a swelling (42) on the lower step, the swelling having a circular section and being centered with the ridge axis and having a diameter that is slightly larger than the ridge thickness, extending beyond the edge thereof, such extension making up a pin (43) that is housed fully in the respective guide-hole (34) of the body.

The pan-support (2) has at its bottom two gas inlet ducts prepared for connection of the piping of the cooking appliance, which inlet ducts converge at the prior vent (45) of the injector, a first duct (46) having a vertical axis designed for connection of the gas in conventional appliances and a second duct (47) with a slightly upwardly inclined axis with the side intake designed for super-slim worktops.

The body (3) profiled by revolving generator, as shown in figures 1 and 2, comprises a hollow central organ (7) making up the premixing draught and a disc-shaped part (8) the periphery of which has an upwardly projecting edge (29) of triangular section with the inner side clipped, which edge has a channel (30) emptying the arc portion facing the hole (31) crossed by the thermocouple, to create an opening for outer air into the precinct (21) housing the thermocouple point.The body is characteristic in having two reliefs (33) on the top face, one on either side of the thermocouple precinct opening channel, the said reliefs being elongate and having an upward semicircular section, and starting from the inner face of the peripheral projecting edge (29), allow the head to be adjusted; the body has the through guide-hole (34) provided on its flat portion for adjustment thereof on the pan-support.

The head (4) is made as a single circular piece, as in figures 5 and 6, and constitutes at the same time the cover (10) forming with the body the expansion chamber (9) of the burner and the distributor of flames through an annular vertical wall (11) with two outlet hole formations for the main flame (28) and the pilot flame (24), which annular wall (11) has two outward concavities, forming with the body (3) respective precincts (20, 21) housing the active points (16, 17) of the plug and the thermocouple, the inner walls of which concavities have particular outlet holes suited to each device.The wall (22) in the concavity (28) for the plug, being of semicircular shape, is fitted with a single outlet hole (23) and at a middle height between the two hole formations; the inner wall (25) of the thermocouple concavity, being straight, has two adjacent holes (26) of a greater diameter than the pilot flame holes, located at a middle height between the two hole formations; the side walls (28) of the concavity associated to the thermocouple are straight and outwardly divergent to expedite cooling of the thermocouple. The two semicircular profile notchings (35) made on the lower edge of the annular wall (11) are located on either side of the concavity (22) associated to the thermocouple.

Another substantial feature of the head is a frustum-of-the cone downward crown (35) under the cover of the plug precinct (20) and coaxial with such device (14).

In accordance with the embodiment shown in figures 7 and 7b, the burner (50), which comprises the same three basic parts of the above-described burner, shown in figures 1 to 6, in other words a head (70), a body (60) and a pan-support (90), and likewise configured as regards the essential characteristics thereof, has the plug (54) precinct (51) and the thermocouple (56) precinct (52) formed between the head (70) and the body (60) so as not to affect the uniformness of the main flame throughout the circular contour thereof, and located adjacent one another covering an arc smaller than the quadrant, in order for the plug and thermocouple to be alternatively visible to or concealed from the user.

As regards the burner head, as in figures 9 to 11, the precinct (51) associated to the plug (54) (figure 7) does not affect the formation of the holes (73) of the main flame, because only the semicircular concavity (80) is formed on the thinner portion (74) of the annular wall (83); the opening to the outside of the precinct has a bore (61) (figure 8) coaxial with the concavity made in the body, with considerably large dimensions for the passage of the plug, in order to affect the peripheral projecting edge (67) of the body and the spark (55) to be optionally visible for the user.

To light the gas it has been provided that the spark (55) directly inflame the gas filling the lighting precinct (51), and from there that the flame extend to the gas housed at the centre (57) for distribution of the pilot flame. Pursuant to figure 10, a swelling (79) on the annular wall (8) thickness above the concavity (80) housing the electrode, allows a horizontal section to delimit the precinct (51) and moreover provide a projecting cant (82) that prevents the spark (55) from passing.

The precinct (52) associated to the thermocouple (56) (figure 7b) is configured by means of a semicircular concavity (81) formed on both parts (71, 74) of the annular wall (83), therefore affecting both formations (73, 75) of flame holes, but the middle thickness has been narrowed to enhance thermocouple cooling; around the holes (77, 78) at a different height of the wall, to heat the thermocouple, a large wall thickness and equal in both is maintained.

The thermocouple crosses the body through a bore (65) fitted to its diameter, the centre of which is also at the same distance from the center of the burner as the plug bore (61).

-In order to center and support the body (60) (figure 8) on the pan-support (figures 12 and 13) and the spacing between both parts leading to the clearance for the entrance of primary air, the peripheral horizontal platform (95) of the pan-support has been provided with four axially projecting wings (91, 93), and hence the gas and air mixing chamber (98) in the pan-support has no obstacles to be cleaned. Additionally, to center the body, and at a distance from the centre of the burner equal to that of the wings (93), a face (66) has been provided slightly inclined in the circular portion of the lower disc (69) surface of the body.

The angle of the body to the pan-support is achieved because a wing (91) of the four, with a non-flat profile differing from the other three, is fitted with a projection (92) that fits under a relief (68) formed radially on the flat horizontal surface of the disc (69) of the body.

In order to achieve a more regular gas-air mixture in the expansion chamber (56), the inner duct of the central cylindrical organ (62) of the body has been provided with a diameter stepping, reducing the section thereof at the same time as the turbulence of the mixture is increased.

We feel that there is no need to extend this description for any expert in the art to have grasped the full scope of the invention and the advantages it offers.

The materials, shape, size and layout of the elements may be altered provided that this entails no modification of the essential features of the invention.

The terms used to describe the invention herein should be taken to have a broad rather than a restrictive meaning.

Claims

1.- A super-slim gas safety burner, in particular for household cooking appliances, fitted with a sparking plug and a safety thermocouple, comprising a pan-support (2), a body (3) and a head (4), where the pan-support constitutes the premixing chamber (5) beneath the cooking worktop surface; wherein the body (3) comprises a central organ (7) constituting the draught of the premixture and a horizontal part (8) diverging towards the outside forms the expansion chamber (9) for the mixture; wherein the head (4) made as a single circular piece, in turn constitutes the cover (10) of the burner and the distributor of flames through an annular wall (11), with two outlet hole formations at different heights; wherein the plug (14) and the thermocouple (15) are fixed to the pan-support and its active points (16, 17) are housed in diametrically opposed cavities in the head, characterised in that the annular wall (11) of the head has two outwardly facing concavities (18, 19), forming with the body (3) the respective precincts (20, 21) wherein are housed the active points of the plug and the thermocouple, and wherein the concavity associated to the precinct (20) of the plug configured with a semicircular front wall (22) is fitted with a specific lighting hole, the concavity being associated to the thermocouple configured with a straight front wall (25) and two straight and outwardly diverging front walls (28), the front wall (25) having two adjacent holes (26) that have a larger diameter than the pilot flame holes, and allow controlled heating of the sensitive thermocouple point (17).

2.- A super-slim gas safety burner, as in claim 1, the body (3) of which is provided on the periphery with a projecting edge (29), characterised in that the said edge is provided with a channel (30) emptied at the arc portion facing the hole (31) of the thermocouple which allows a greater access of outside air.

3.- A super-slim gas safety burner, as in claim 1, characterised in that the body (3) has two elongate reliefs (33) on the top face that allow the head to be adjusted, and in that the said body (3) is provided with a through hole (30) allowing the guiding and subsequent adjustment thereof on the pan-support (2).

4.- A super-slim gas safety burner, as in claim 1, characterised in that the head is provided, beneath the cover of the precinct (20) associated to the plug, with a downwardly facing crown (35), coaxial with the said plug (14), to form the electric lighting arc, and in that the lower edge of the annular wall (11) is provided with two semicircular notchings (35) for adjustment with the body.

5.- A super-slim gas safety burner, as in claim 1, wherein the pan-support (2) is structurally provided with several angularly distributed inner radial ridges (37), characterised in that the said ridges (37) project above the surface to fix such pan-support and the top edges thereof have a stepped profile on their top edge, with a high step (39) expediting pre-centering of the body on the pan-support, and the low step (40) allowing final stable support of the body and the spacing thereof from the cooking worktop tray, delimiting the entrance (41) of outer primary air into the burner.

6.- A super-slim gas safety burner, as in claims 1 and 5, characterised in that at least one of the radial ridges of the pan-support has on the top edge of the ridge a swelling (42) of circular section thickness centered with the ridge axis, constituting above the edge thereof a pin (43) that shall be fully housed in the relevant guide-hole (34) of the body.

7.- A super-slim gas safety burner, as in claim 1, characterised in that the pan-support (2) has on its bottom two gas inlet ducts for connection of each of the different cooking appliances, converging at the prior intake (45) to the premixing chamber, a first duct (46) with a vertical axis and a second duct (47) with an axis that is slightly inclined upwards with the side intake.

8.- A super-slim gas safety burner, as in claim 1, characterised in that in a different embodiment of the invention the concavities (80-81) configuring the precincts (51, 52) for the sparking plug and for the flame-detecting thermocouple between the head (70) and the body (60) are semicircular, the lighting precinct (51) by conformation only of the narrower portion (74) or distributing the pilot flame of the annular wall (83), opening to the outside with the assistance of a peripheral coaxial bore (61) provided in the body (60) for the passage of the plug (54), which bore is considerably oversized as compared with the latter, which affects the peripheral projecting edge (67) of the body (60) for the spark (55) to be seen from outside the burner, and the flame-detecting precinct (52) by conformation of both (71, 74) parts of the annular wall (83), both precincts being at less than a 900 angle to each other

9.- A super-slim gas safety burner, as in claim 8, characterised in that the lighting precinct (51) is delimited above the plug (54) by means of a horizontal section of the annular wall (83) itself that is swollen above the precinct (51), which swelling (79) provides a cant (82) projecting towards the periphery through which the plug spark (55) cannot pass during lighting.

10.- A super-slim gas safety burner, as in claim 8, characterised in that the flame-detecting precinct (52) is configured by means of concavities (81) provided on both parts (71, 74) of the annular wall distributing flames, which concavities have an irregular wall thickness that is determined for the thermocouple heating specific holes (77, 78).

11.- A super-slim gas safety burner, as in claims 1 and 8, wherein the body (60) has a cylindrical central organ ducting the fuel mixture characterised in that the inner cylindrical central organ (62) of the duct is provided with a diameter stepping.

12.- A super-slim gas safety burner, as in claims 1 and 8, wherein the body (60) is positioned on the pan-support (90) with an intermediate clearance for the inlet of primary air and wherein the inside of the pan-support (90) makes up the fuel mixing chamber characterised in that to center the same and support the body, the peripheral platform (95) of the pan-support is provided with four axially projecting wings (91, 93) with a height given by the said clearance, and for angular positioning thereof, one such wing (93) being provided with a projection (92) that fits under a relief (68) of the body (60) disc (69).

13.- A gas safety burner fitted with a sparking plug and a safety thermocouple and comprising a pan-support, a body and a head, wherein the head includes an annular wall which has outlet hole formations to act as a distributor of the flames and which has two outwardly facing concavities in one of which are housed active parts of the sparking plug and in the other of which are housed active parts of the thermocouple.

14.- A gas safety burner substantially as herein described with reference to and as illustrated by Figs. 1 to 6 or by Figs. 7 to 12 of the accompanying drawings.