BURNER WITH LOW-TEMPERATURE CAP

Abstract

A burner has a body suitable for containing at least one injector, a crown disposed on the body, and a cap disposed on the crown. The geometrical structure of the crown and of the cap is such to stabilize the flames with a minimum contact between the flames and the cap, in such a way to minimize the temperature of the cap when the burner is used.

Claims

1. Burner comprising: a body suitable for containing at least one injector a crown disposed on the body; and a cap disposed on the crown; said crown comprising: a truncated conical lateral edge with decreasing diameter going from down up and inclination comprised between 20°-70° relative to a horizontal plane; a plurality of apertures with U-shape in front view, which extend radially in the lateral edge (31) of the crown for the emission of the flames; said cap having a lateral edge that comprises: a first truncated conical portion with downward inclination of approximately 10°-25° relative to a horizontal plane; and a second truncated conical portion with downward inclination of approximately 30°-70° relative to a horizontal plane; and a lower surface inclined by an angle of approximately 8°-25° relative to a horizontal plane, which is disposed on the apertures of the crown.

2. The burner of claim 1, wherein each aperture comprises a first channel and a second channel disposed in more peripheral position than the first channel, said second channel being larger than the first channel.

3. The burner of claim 1, wherein the second truncated conical portion of the lateral edge of the cap is disposed in coplanar position with the lateral edge of the crown.

4. The burner of claim 2, wherein the first channel is higher than the second channel.

5. The burner of claim 1, wherein a U-shaped step is defined between the first channel and the second channel.

6. The burner of claim 1, wherein the bottom walls of the first channel and of the second channel are inclined upwards by approximately 8°-25° relative to a horizontal plane, in such a way that said apertures of the crown have an emission axis of the flames with upward inclination of 8°-25° relative to a horizontal plane.

7. The burner of claim 1, wherein said cap comprises a plurality of ribs that protrude in upper position from an upper planar surface of the cap.

8. The burner of claim 1, wherein said cap is made of aluminum.

9. Burner comprising: a body suitable for containing at least one injector; a crown disposed on the body; and a cap disposed on the crown; said crown comprising: a truncated conical lateral edge with decreasing diameter from down up and inclination comprised between 20°-70° relative to a horizontal plane; and a cylindrical seat that is open on top, wherein the cap is disposed; the cylindrical seat (34) having a cylindrical lateral wall (35); said cap having a lateral edge that comprises: a first truncated conical portion with downward inclination of approximately 20°-70° relative to a horizontal plane; a second cylindrical portion; a lower horizontal surface; and a plurality of apertures for the flames obtained in the first truncated conical portion of the lateral edge of the cap; said apertures being through holes with an emission axis of the flames that is inclined upwards by approximately 20°-70° relative to a horizontal plane; wherein the first cylindrical portion of the lateral edge of the cap is disposed in distal position relative to the cylindrical lateral wall of the seat of the crown, in such a way to define an annular gap for the emission of a pilot flame; characterized in that said cap has an upper surface with circular planar horizontal shape, which is recessed relative to a joining surface that joins the upper surface with the lateral edge; wherein the joining surface is inclined upwards relative to the upper surface by an angle comprised between 18°-22° relative to a horizontal plane.

10. The burner of claim 9, wherein the first truncated conical portion of the lateral edge of the cap is disposed in coplanar position with the truncated conical lateral edge of the crown.

11. The burner of claim 9, wherein each aperture of the cap is shaped like a rectangular trapezium, in radial section.

12. The burner of claim 9, wherein said cap is made of aluminum.

13. Burner comprising: a body suitable for containing at least one injector; a crown disposed on the body; and a cap disposed on the crown; said crown comprising: a truncated conical lateral edge with decreasing diameter from down up and inclination comprised between 20°-70° relative to a horizontal plane; and a cylindrical seat that is open on top, wherein the cap is disposed in such a way to define a distribution chamber of air-gas mixture between the crown and the cap; the cylindrical seat having a cylindrical lateral wall; said cap having a lateral edge that comprises: a first truncated conical portion with downward inclination of 20°-70° relative to a horizontal plane; a second cylindrical portion; a lower horizontal surface with a step; and a plurality of apertures for the flames obtained in the first truncated conical portion of the lateral edge of the cap; said apertures being through holes with an emission axis of the flames that is inclined upwards by approximately 20°-70° relative to a horizontal plane; wherein the first cylindrical portion of the lateral edge of the cap is disposed in distal position relative to the cylindrical lateral wall of the seat of the crown, in such a way to define an annular gap for the emission of a pilot flame; said crown comprising an annular collar that protrudes upwards and suitable for supporting said step of the cap; the annular collar having an upper edge with a plurality of cavities; characterized in that said cap is die-cast and the apertures of the cap have an axial length of approximately 5-6 mm; and said cavities of the annular collar of the crown have a radial horizontal axis and are arranged radially outwards with respect to an inlet of the apertures of the cap in such a way to feed air-gas mixture in said annular gap for the pilot flame.

14. The burner of claim 13, wherein said cap is made of aluminum.

Description

[0043] With reference to FIGS. 2-5, a first embodiment of a burner according to the invention is disclosed, which is generally indicated with reference numeral (100).

[0044] In the following description, elements that are identical or correspond to the ones described above will be indicated with the same numerals, omitting their detailed description.

[0045] The crown (3) has a truncated conical lateral edge (31) with a decreasing diameter going from the bottom upwards and an inclination comprised between 20°-70°, preferably 40-50°, more preferably 45°, relative to a horizontal plane that is orthogonal to a vertical axis (Y) of the burner.

[0046] A plurality of apertures (30) is radially obtained in the lateral edge (31) of the crown for the emission of flames.

[0047] Each aperture (30) is open towards the top and has a substantially “U”-shape in a front view. Each aperture (30) has a first channel (30a) and a second channel (30b) disposed in more peripheral position than the first channel. The second channel (30b) is larger than the first channel. In view of the above, a U-shaped step (32) is defined between the first channel (30a) and the second channel (30b). The first channel (30a) is longer than the second channel (30b). The first channel (30a) is higher than the second channel (30b).

[0048] The bottom walls of the first channel (30a) and of the second channel (30b) are inclined upwards by approximately 8°-25°, preferably 10°, relative to a horizontal plane, in such a way that said apertures (30) of the crown have an emission axis (X) of the flames that is inclined upwards by 8°-25°, preferably 10°, relative to a horizontal plane.

[0049] The cap (4) has an upper surface (45) with a circular planar horizontal shape and an inclined lateral edge (40). The lateral edge (40) comprises: [0050] a first truncated conical portion (40a) with downward inclination of approximately 10°-25°, preferably 15-21°, more preferably 18°, relative to a horizontal plane, and [0051] a second truncated conical portion (40b) with an inclination of approximately 30°-70°, preferably 40-50°, more preferably 45°, relative to a horizontal plane.

[0052] The lateral edge (40) of the cap has a lower surface (41) that is inclined by an angle of approximately 8-25°, preferably 10°, relative to a horizontal plane. The lower surface (41) of the lateral edge of the cap is joined with a bottom surface (46) disposed along a horizontal plane.

[0053] The lower surface (41) of the lateral edge of the cap is disposed on the apertures (30) of the crown, in such a way to cover the first channel (30a) and the second channel (30b).

[0054] The second truncated conical portion (40b) of the lateral edge of the cap is disposed in coplanar position with the lateral edge (31) of the crown.

[0055] The lower surface (41) of the lateral edge of the cap is disposed in parallel position relative to the bottom walls of the first channel (30a) and of the second channel (30b) and in parallel position relative to the emission axis (X) of the flames.

[0056] An empty space (I) is formed between an upper edge of the second channel (30b) and the lower wall (41) of the lateral edge of the cap.

[0057] FIG. 5 shows the flames that are emitted from the apertures (30) of the crown. FIG. 5A shows a flame (F1) at maximum power and FIG. 5B shows a flame (F2) at minimum power.

[0058] The flame (F1) at maximum power and the flame (F2) at minimum power minimally touch the cap and do not embrace the lateral edge of the cap.

[0059] The special geometry of the apertures (30) of the crown and of the lateral edge of the cap (4) makes it possible to obtain a temperature value of the cap (4) that is lower than 500° C. during use.

[0060] The special shape of the lateral edge (40) and of the lower surface (41) of the lateral edge of the cap makes it possible to stabilize the flames and minimize the contact surface between the flames and the cap. In view of the above, the annular rib of the caps according to the prior art can be eliminated.

[0061] FIG. 6 shows a variant of the cap (4), wherein a plurality of parallel straight ribs (47) protrude from the top of the upper surface (45) of the cap.

[0062] Each rib (47) is provided with inclined ending portions (48).

[0063] With reference to FIGS. 7-10, a second embodiment of a burner according to the invention is disclosed, which is generally indicated with reference numeral (200). The crown (3) has a truncated conical lateral edge (31) with increasing diameter going from the bottom upwards and inclination comprised between 20°-70°, preferably 25-35°, more preferably 30°, relative to a horizontal plane.

[0064] The crown (3) has a cylindrical seat (34) that is open on top, wherein the cap (4) is disposed. The cylindrical seat (34) has a cylindrical lateral wall (35).

[0065] The cap (4) has an upper surface (45) with a circular planar horizontal shape. The upper surface (45) is recessed relative to a joining surface (44) that joins the upper surface (45) with a lateral edge (40).

[0066] The joining surface (44) is inclined upwards relative to the upper surface (45) by an angle comprised between 18°-22°, preferably 20°, relative to a horizontal plane.

[0067] The lateral edge (40) comprises: [0068] a first truncated conical portion (40a) with downward inclination of 20°-70°, preferably 25-35°, more preferably 30°, relative to a horizontal plane, and [0069] a second cylindrical portion (40b).

[0070] The second cylindrical portion (40b) of the lateral edge of the cap is disposed in distal position relative to the cylindrical lateral wall (35) of the seat of the crown, in such a way to define an annular gap (36).

[0071] The lateral edge (40) of the cap has a lower horizontal surface (41). The lower surface (41) of the lateral edge of the cap is joined with a lower joining surface (43) that is joined with a bottom surface (46) disposed along a horizontal plane.

[0072] The lower joining surface (43) is substantially parallel to the first truncated conical portion (40a) of the lateral edge of the cap.

[0073] A plurality of apertures (42) for the flames of the cooking hob is obtained in the first truncated conical portion (40a) of the lateral edge of the cap. The apertures (42) are through holes shaped like a slot, for example a rectangular slot with rounded corners. Said apertures (42) have an emission axis (X) of the flames that is orthogonal to the first truncated conical portion (40a) of the lateral edge of the cap. Otherwise said, the axis (X) of the apertures (42) is inclined by 20°-70°, preferably 55-65°, more preferably 60°, relative to a horizontal plane.

[0074] Each aperture (42) of the cap is shaped like a rectangular trapezium, in radial section. The inlet section (42a) of each aperture (42) is larger than an outlet section (42b).

[0075] FIG. 10 shows the flames that are emitted from the apertures (42) of the cap. FIG. 10A shows a flame (F1) at maximum power and FIG. 10B shows a flame (F2) at minimum power.

[0076] A pilot flame (F3) is emitted from the annular gap (36) between the second cylindrical portion (40b) of the lateral edge of the cap and the cylindrical lateral wall (36) of the seat of the crown.

[0077] The pilot flame (F3) is disposed under the primary flames.

[0078] Also in this case, the pilot flame (F3), the flame (F1) at maximum power and the flame (F2) at minimum power minimally touch the cap and do not embrace the lateral edge of the cap.

[0079] The special geometry of the crown (3), of the cap (4) and of the apertures (42) of the cap makes it possible to obtain a temperature value of the cap (4) that is lower than 500° C. during use.

[0080] In particular, the provision of the pilot flame (F3) at the output of the annular gap (36) makes it possible to stabilize the flames and minimize the contact surface between the flames and the cap. In this way, the annular rib of the cap according to the prior art can be eliminated.

[0081] With reference to FIG. 11-15, a third embodiment of a burner according to the invention is disclosed, which is generally indicated with reference numeral (300).

[0082] The crown (3) has a cylindrical seat (34) that is open on top, wherein the cap (4) is disposed so that a distribution chamber of air-gas mixture is defined between the crown and the cap. The cylindrical seat (34) has a cylindrical lateral wall (35).

[0083] An annular collar (37) that protrudes upwards is disposed in the cylindrical seat (34). The annular collar (37) has an upper edge with a plurality of cavities (38).

[0084] The cap (4) has a central upper surface (45) with a circular planar horizontal shape and a peripheral upper surface (45a) with truncated conical shape with increasing diameter from down upwards, with an inclination of approximately 1-15° relative to a horizontal plane.

[0085] The cap (4) has a lateral edge (40) that comprises: [0086] a first truncated conical portion (40a) with a downward inclination of approximately 20° -70°, preferably 25-35°, more preferably 30°, relative to a horizontal plane, and [0087] a second cylindrical portion (40b).

[0088] The second cylindrical portion (40b) of the lateral edge of the cap is disposed in distal position relative to the cylindrical lateral wall (35) of the seat of the crown, in such a way to define an annular gap (36) for the pilot flames (F3).

[0089] The lateral edge (40) of the cap has a horizontal lower surface (41) that continues with a step (49) in contact with the collar (37) in such a way that the lower surface (41) is spaced from the crown for the passage of air-gas mixture in the annular gap (36) for the pilot flames. The step (49) is joined with a joining surface (43) that is substantially parallel to the first truncated conical portion (40a) of the lateral edge of the cap.

[0090] With reference to FIG. 14A, a plurality of apertures (42) for the flames of the cooking hob is obtained in the first truncated conical portion (40a) of the lateral edge of the cap. The cap (40) is not made of low-thickness sheet metal, and is obtained by means of die-casting, and the apertures (42) are circular through holes with an axial length of approximately 5-6 mm. Said apertures (42) have an emission axis (X) of the flames that is orthogonal to the first truncated conical portion (40a) of the lateral edge of the cap. The axis (X) of the apertures (42) is inclined by 20°-70°, preferably 55-65°, more preferably 60°, relative to a horizontal plane. The high axial length of the apertures (42) makes it possible to keep the desired direction of the flames that are emitted from the apertures (42) of the cap, in such a way that the burner (300) can meet the requirements of a backfire test with liquid gases.

[0091] Each aperture (42) has an inlet (42a) and an outlet (42b).

[0092] It must be noted that the cavities (38) of the annular collar of the crown have a radial horizontal axis (Z). Moreover, the cavities (38) are disposed outwards in radial direction relative to the inlet (42a) of the apertures of the cap. Consequently, the air-gas mixture in the distribution channel flows outwards in radial direction and is divided in parts. Otherwise said, a part of the air-gas mixture flows into the apertures (42) in the direction of the axis (X) of the apertures (42) to feed the primary flames and a part of the air-gas mixture flows in the cavities (38) of the collar in the direction of the axis (Z) of the cavities to feed the annular gap (36) where the pilot flames are formed.

[0093] Such an arrangement of the cavities (38) makes it possible to feed the pilot flames correctly, stabilize the primary flames and minimize the contact surface between the flames and the cap, in such a way to obtain a die-cast cap made of a material that can withstand a temperature value lower than 500° C.

[0094] FIG. 15 shows a flame (F1) at maximum power in the circle (A) and a flame (F2) at minimum power in the circle (B).

[0095] A pilot flame (F3) is emitted from the annular gap (36) and is disposed under the primary flames.

[0096] Also in this case, the pilot flame (F3), the flame (F1) at maximum power and the flame (F2) at minimum power minimally touch the cap and do not embrace the lateral edge of the cap.

[0097] The caps (4) of the burners (100; 200; 300) according to the invention can be made with materials other than brass and steel, such as for example materials that can withstand a temperature value lower than or equal to 500° C. For example, the caps (4) can be made of die-cast aluminum.