CN220750185U

CN220750185U - Fire cover assembly for kitchen range

Info

Publication number: CN220750185U
Application number: CN202321407826.0U
Authority: CN
Inventors: 孙红梅; 欧伟成; 潘叶江
Original assignee: Vatti Co Ltd
Current assignee: Vatti Co Ltd
Priority date: 2023-06-05
Filing date: 2023-06-05
Publication date: 2024-04-09
Anticipated expiration: 2033-06-05

Abstract

The utility model discloses a fire lid assembly for a kitchen range, comprising: the lower fire cover is provided with a central hole for the fuel gas to pass through, and the peripheral wall of the lower fire cover is provided with an ignition hole group communicated with the central hole; and the upper fire cover is arranged at the top of the lower fire cover, the upper fire cover and the central hole are surrounded to form a gas mixing cavity, an upper annular fire groove for the fuel gas to pass through is formed between the bottom of the upper fire cover and the top of the lower fire cover, and the radial inner end of the upper annular fire groove is communicated with the gas mixing cavity. The fire cover assembly is simple in structure, can form thin flame type annular flame, improves the thermal efficiency and reduces the content of CO.

Description

Fire cover assembly for kitchen range

Technical Field

The utility model relates to the technical field of stoves, in particular to a fire cover assembly for a stove.

Background

The existing internal fire cover has the fire discharging mode that the mixture of the fuel gas and the air is sprayed out from the fire hole at a certain speed, and flames are distributed on the periphery of the internal fire cover and spread outwards. In order to obtain sufficient secondary air, the flame is continuously lengthened, the flame temperature is reduced because excessive secondary air participates in combustion, and meanwhile, the high-temperature flame is outwards dispersed and cannot be focused on the bottom of the pot, so that the thermal efficiency of the combustion is not high.

In addition, the secondary air passage area is insufficient, and the exceeding of the CO content in the flue gas is easy to occur. In order to supplement secondary air in the fire holes of the burner, a certain distance is reserved between the fire holes of the inner fire cover, and the gap is generally double the diameter of the fire holes, so that the temperature of the gap between the fire holes is lower, a high-temperature area of flame is in punctiform contact with the bottom of the cooker, and the heat energy utilization rate is not high.

Disclosure of Invention

The utility model aims to solve at least one of the problems existing in the related art to a certain extent, and therefore, the utility model provides a fire cover assembly for a kitchen range, which has a simple structure, can form a thin flame type annular flame, improves the heat efficiency and reduces the content of CO.

According to the fire cover assembly for the kitchen range, the fire cover assembly is realized through the following technical scheme:

a fire lid assembly for a cooktop, comprising: the lower fire cover is provided with a central hole for the fuel gas to pass through, and the peripheral wall of the lower fire cover is provided with an ignition hole group communicated with the central hole; and the upper fire cover is arranged at the top of the lower fire cover, the upper fire cover and the central hole are surrounded to form a gas mixing cavity, an upper annular fire groove for the fuel gas to pass through is formed between the bottom of the upper fire cover and the top of the lower fire cover, and the radial inner end of the upper annular fire groove is communicated with the gas mixing cavity.

In some embodiments, the upper annular firebox has a width in the vertical direction of 0.8 to 2mm.

In some embodiments, the upper annular firebox is vertically adjustable in width.

In some embodiments, the upper groove wall surface and/or the lower groove wall surface of the upper annular fire groove are from inside to outside

In some embodiments, a cap peak extending outwards is fixedly arranged at the upper end or the outer edge of the top of the outer side wall of the upper fire cover, and the cap peak is positioned right above the ignition hole group; and/or, the top of the upper fire cover is provided with an upward-opening liquid containing cavity and an overflow port, and the overflow port is communicated with the liquid containing cavity and is used for discharging overflow liquid in the liquid containing cavity.

In some embodiments, the lower fire cover is provided with a flame stabilizing structure positioned below the upper annular fire groove, and/or a mounting part suitable for being matched and spliced with the furnace end is arranged at the bottom of the lower fire cover.

In some embodiments, the flame stabilizing structure is a flame stabilizing hole, a plurality of flame stabilizing holes are circumferentially arranged at intervals on the peripheral wall of the lower fire cover or the upper fire cover, and each flame stabilizing hole is radially arranged and the radially inner end of each flame stabilizing hole is communicated with the air mixing cavity; or the flame stabilizing structure is an upper flame stabilizing groove, the top or the bottom of the lower flame cover is provided with a plurality of upper flame stabilizing grooves, or the bottom of the upper flame cover is provided with a plurality of upper flame stabilizing grooves, and each upper flame stabilizing groove is arranged along the radial direction and the radial inner end of each upper flame stabilizing groove is communicated with the air mixing cavity.

In some embodiments, the width of the upper flame holding groove in the circumferential direction is 0.8 to 2mm, and the depth of the upper flame holding groove in the vertical direction is 0.8 to 1.5mm.

In some embodiments, an inwardly extending boss is fixedly arranged on the inner annular wall of the lower fire cover, and a positioning part is fixedly arranged at the position of the upper fire cover corresponding to the boss, and is riveted with the boss or connected and fixed through a connecting piece.

In some embodiments, the device further comprises an annular base, wherein the annular base is arranged at the bottom of the lower fire cover and is fixedly connected with the lower fire cover and/or the upper fire cover, and the annular base is provided with a through hole communicated with the central hole.

In some embodiments, the lower fire cover bottom abuts the annular base top; or a lower annular fire groove is formed between the bottom of the lower fire cover and the top of the annular base, and the radial inner end of the lower annular fire groove is communicated with the through hole and/or the central hole.

In some embodiments, the lower annular fire groove has a width in a vertical direction of 0.8 to 2mm, and the lower annular fire groove has a width greater than the upper annular fire groove.

In some embodiments, a plurality of lower flame stabilizing grooves are formed in the top of the annular base, and each lower flame stabilizing groove is arranged in the radial direction and the radial inner end of each lower flame stabilizing groove is communicated with the through hole; or, a plurality of flame stabilizing holes are formed in the side wall of the annular base at intervals along the circumferential direction, and the flame stabilizing holes in the annular base are communicated with the through holes.

In some embodiments, the width of the lower flame holding groove in the circumferential direction is 0.8 to 2mm, and the depth of the lower flame holding groove in the vertical direction is 0.8 to 1.5mm.

In some embodiments, an inwardly extending lug is fixedly arranged on the inner annular wall of the annular base, and the lug is riveted with the upper fire cover and/or the lower fire cover or is fixedly connected with the upper fire cover and/or the lower fire cover through a connecting piece; and/or the bottom of the annular base is provided with a mounting part which is suitable for being matched and spliced with the furnace end.

Compared with the prior art, the utility model at least comprises the following beneficial effects:

according to the inner fire cover assembly, the upper fire cover and the lower fire cover are enclosed to form the downward opening air mixing cavity, the upper annular fire groove communicated with the air mixing cavity is formed between the upper fire cover and the lower fire cover, fuel gas in the air mixing cavity is sprayed outwards from the upper annular fire groove and is ignited to form thin flame type annular flame, the contact area between the Bao Yan type annular flame and air is increased, the full contact between unburned fuel gas in the flame and air is facilitated, the combustion sufficiency is improved, the CO content in flue gas is reduced, and meanwhile, the thin flame type annular flame forms a sheet shape to perform heat exchange with the pot bottom, so that the temperature of the pot bottom is facilitated to be increased, and the thermal efficiency of a gas cooker is improved.

Drawings

FIG. 1 is a schematic view showing the construction of a fire cover assembly according to embodiment 1 of the present utility model;

FIG. 2 is a cross-sectional view of a fire cover assembly in accordance with example 1 of the present utility model;

FIG. 3 is a second cross-sectional view of the fire cover assembly of example 1 of the present utility model;

FIG. 4 is a cross-sectional view of a fire cover assembly in accordance with example 2 of the present utility model;

FIG. 5 is a cross-sectional view of another fire cover assembly in accordance with embodiment 2 of the utility model;

FIG. 6 is a schematic view showing the construction of a fire cover assembly in embodiment 3 of the present utility model;

FIG. 7 is an exploded view of the fire cover assembly in example 3 of the present utility model;

FIG. 8 is a cross-sectional view of a fire cover assembly in accordance with example 3 of the present utility model;

FIG. 9 is an exploded view of the fire cover assembly of example 4 of the present utility model;

fig. 10 is a cross-sectional view of a fire cover assembly in example 4 of the present utility model.

In the figure: 1-a lower fire cover, 11-a central hole, 12-an ignition hole, 13-a boss, 151-an upper flame stabilizing groove, 161-an annular vertical edge and 162-a convex rib; 2-an upper fire cover, 21-a chamber, 22-a positioning part, 23-a cap peak, 241-Cheng Yeqiang and 242-an overflow port; 31-a mixing cavity, 32-an upper annular fire groove; 4-connecting piece; 5-annular base, 51-through hole, 52-lower flame stabilizing groove, 53-lug.

Detailed Description

The following examples illustrate the utility model, but the utility model is not limited to these examples. Modifications and equivalents of some of the technical features of the specific embodiments of the present utility model may be made without departing from the spirit of the present utility model, and they are all included in the scope of the claimed utility model.

Example 1

Referring to fig. 1-2, the present embodiment provides a fire cover assembly for a kitchen range, comprising a lower fire cover 1 and an upper fire cover 2, wherein a central hole 11 for gas to pass through is formed in the center of the lower fire cover 1, an ignition hole group communicating with the central hole 11 is formed in the peripheral wall of the lower fire cover 1, and the ignition hole group is composed of 3-5 ignition holes 12. The upper fire cover 2 is arranged on the top of the lower fire cover 1 and is connected with the lower fire cover 1 so that the upper fire cover and the lower fire cover form a whole. The upper fire cover 2 and the central hole 11 are surrounded to form a gas mixing cavity 31 with a downward opening, an upper annular fire groove 321 for gas to pass through is formed between the bottom of the upper fire cover 2 and the top of the lower fire cover 1, and the radial inner end of the upper annular fire groove 321 is communicated with the gas mixing cavity 31, so that gas in the gas mixing cavity is sprayed outwards from the upper annular fire groove and ignited to form thin flame type annular flame, the contact area between Bao Yan type annular flame and air is increased, the full contact between unburned gas and air in the flame is facilitated, the combustion sufficiency is improved, and the CO content in flue gas is reduced; meanwhile, the high-temperature areas of the Bao Yan annular flames are distributed in a sheet shape, and the high-temperature flames are subjected to heat exchange with the bottom of the cooker, so that the temperature of the bottom of the cooker is improved, and the heat efficiency of the gas cooker is improved.

Further, the upper annular flame groove 321 has a width of 0.8 to 2mm in the vertical direction. When the lower fire cover 1 and the upper fire cover 2 are riveted or fixed by a screw, the width of the upper annular fire groove 321 in the vertical direction is fixed; when the lower fire cover 1 and the upper fire cover 2 are connected and fixed through the connecting piece 4 (such as a screw), the matching degree of the connecting piece 4 and the lower fire cover 1 and the upper fire cover 2 can be adjusted, so that the width of the upper annular fire groove 321 in the vertical direction can be adjusted, and the width of the annular fire groove 21 can be adjusted to form different firepower, so that the device can be suitable for different use places or air sources.

In this embodiment, the upper and lower groove wall surfaces of the upper annular flame groove 321 are all inclined from inside to outside and upward, and the inclination angles of the upper and lower groove wall surfaces are all 30-70 °, so that the inclination angle range of the upper annular flame groove 321 is 30-70 °, and thus fuel gas is sprayed upward obliquely along the upper annular flame groove 321 at a certain angle, which is more beneficial to forming a thin flame type annular flame. In this embodiment, the upper groove wall surface of the upper annular flame groove 321 may be designed as an inclined surface which is inclined upward from inside to outside, and the lower groove wall surface may be designed as a horizontal surface.

Referring to fig. 1-3, the upper fire cover 2 is provided with a downwardly opening chamber 21, and the chamber 21 and the central hole 11 are enclosed to form a mixing chamber 31. The upper end or the top outer edge of the outer side wall of the upper fire cover 2 is integrally formed with a cap peak 23 extending outwards, and the cap peak 23 is positioned right above the ignition hole group so as to prevent the overflow liquid from falling to the ignition hole group to block the ignition hole group. In addition, in order to enable the fire cover assembly (i.e. the upper fire cover) to receive overflow, and also to enable overflow to automatically flow from the top of the upper fire cover to the cooking bench, a liquid containing cavity 241 and an overflow port 242 which are upwardly opened are arranged at the top of the upper fire cover 2, and the overflow port 152 penetrates through the cavity wall of the liquid containing cavity 151, and the radial inner end of the overflow port is communicated with the liquid containing cavity 151 for discharging the overflow liquid in the liquid containing cavity 241. Further, the width of the overflow port 242 in the circumferential direction is 5-8 mm, and/or the bottom surface of the overflow port 242 is arranged obliquely from inside to outside and downward, so that overflow discharge can be guided more conveniently.

In this embodiment, the fixing manner of the upper and lower fire covers includes, but is not limited to, any one of the following:

first, referring to fig. 1-2, two bosses 13 extending inwards are integrally formed on the inner annular wall of the lower fire cover 1, the two bosses 13 extend into the central hole 11 and are symmetrically arranged, a positioning part 22 is fixedly arranged at the position of the upper fire cover 2 corresponding to the boss 13, the positioning part 22 is positioned in the cavity 21 and right above the corresponding boss 13, and the positioning part 22 is abutted against the corresponding boss 13, so that the two bosses can be in clearance fit. The fire cover assembly further comprises a connecting piece 4, wherein the connecting piece 4 is preferably a screw, and the screw penetrates through the boss 13 from bottom to top and is connected and fixed with the positioning part 22, so that the upper fire cover and the lower fire cover are stably and reliably connected into a whole through the connecting piece 4. Thus, in order to make the width of the upper annular flame groove 321 adjustable, the width of the upper annular flame groove 321 in the vertical direction can be changed by adjusting the fitting depth of the screw and the positioning portion 22.

Second, compared with the first, the connector 4 is omitted, and at this time, the positioning portion 22 of the upper fire cover 2 is riveted with the boss 13 of the lower fire cover 1, and after the riveting, the width of the upper annular fire groove 321 in the vertical direction is fixed.

In order to make the fire cover assembly have the function of stabilizing flame, a flame stabilizing structure positioned below the upper annular fire groove 321 can be additionally arranged on the lower fire cover 1. Referring to fig. 3, the flame stabilizing structure is an upper flame stabilizing groove 151, a plurality of upper flame stabilizing grooves 151 are formed at the top of the lower flame cover 1, each upper flame stabilizing groove 151 is arranged in a radial direction and the radial inner end of each upper flame stabilizing groove 151 is communicated with the air mixing cavity 31, so that the phenomenon that the annular flame formed at the upper annular flame groove 321 is unstable and is separated from the flame is prevented through the plurality of upper flame stabilizing grooves 151, and the flame stability at the upper annular flame groove 321 is maintained. Further, the width of the upper flame holding groove 151 in the circumferential direction is 0.8 to 2mm, and the depth of the upper flame holding groove 151 in the vertical direction is 0.8 to 1.5mm.

Of course, the installation position of the upper flame stabilizing grooves 151 may be changed, that is, all the upper flame stabilizing grooves 151 are circumferentially spaced apart from the bottom of the upper flame cover 2 or the lower flame cover 1. In addition, instead of the upper flame stabilizing groove 151, a plurality of flame stabilizing holes are provided on the peripheral wall of the lower flame cover 1 at intervals in the circumferential direction, each flame stabilizing hole being disposed in the radial direction and communicating with the air mixing chamber 31 at the radially inner end thereof.

Example 2

Referring to fig. 4 or 5, this embodiment is different from embodiment 1 in that a mounting portion (not shown) adapted to be fitted with a burner is provided at the bottom of lower fire cover 1. The installation part can be an annular standing edge 161, referring to fig. 4, the bottom of the lower fire cover 1 is integrally formed with the annular standing edge 161 extending downwards, and a notch is formed on the annular standing edge 161, so that the connection piece can be conveniently disassembled and assembled through the notch, and secondary air required by combustion is supplemented for the air mixing cavity 31. Of course, the mounting portion may be a plurality of ribs 162, and referring to fig. 5, a plurality of ribs 162 extending downward are integrally formed at the bottom of the lower fire cover 1, all the ribs 162 are circumferentially spaced apart, and gaps for the passage of secondary air are formed between adjacent ribs 162.

It can be seen that by integrating the mounting portion adapted to be fitted with the burner at the bottom of the lower fire cover 1, the fire cover assembly can be stably and reliably mounted on the burner without the additional aid of the annular base 5 as described in embodiment 3, preventing the occurrence of radial displacement after the fire cover assembly is mounted.

Example 3

Referring to fig. 6 to 8, this embodiment is different from embodiment 1 in that the fire cover assembly further includes an annular base 5, and the annular base 5 is disposed at the bottom of the lower fire cover 1 and is fixedly connected to the lower fire cover 1 and/or the upper fire cover 2, so that the upper and lower fire covers and the annular base 5 are integrally connected. A through hole 51 communicating with the center hole 11 is provided at the center position of the annular base 5.

In this embodiment, a lower annular flame groove 322 is formed between the bottom of the lower flame cover 1 and the top of the annular base 5, and the radially inner end of the lower annular flame groove 322 communicates with the through hole 51 and/or the central hole 11 to achieve the cooperation of the upper and lower annular flame grooves, thereby forming two groups of annular flames. Further, the width of the lower annular fire groove 322 in the vertical direction is 0.8-2 mm, and the width of the lower annular fire groove 322 is larger than that of the upper annular fire groove 321, so that the demand of secondary air is reduced by reducing the heat flow of the upper annular fire groove 321, the problem that the secondary air of the upper annular fire groove 321 is difficult to supplement is effectively solved, and the content of CO in flue gas is reduced. In other embodiments, the bottom of lower fire cover 1 may be designed to abut the top of annular base 5.

Further, two lugs 53 extending inwards are fixedly arranged on the inner annular wall of the annular base 5, each lug 53 extends into the through hole 51 and is arranged in one-to-one correspondence with the boss 13 in the lower fire cover 1, and each lug 53 abuts against the corresponding boss 13. The connecting piece 4 sequentially passes through the lug 53 and the boss 13 from bottom to top and is fixedly connected with the positioning part 22, so that the upper fire cover, the lower fire cover and the annular base 5 are connected into a whole through the same connecting piece 4. Of course, the lug 53 and the boss 13 may be connected by caulking instead.

In order to facilitate the stable and reliable installation of the fire cover assembly on the burner head through the annular base 5, a mounting part (not shown in the figure) which extends downwards and is suitable for being matched and inserted with the burner head is integrally formed at the bottom of the annular base 5. The mounting part can be an annular standing edge 161 with a notch or a plurality of ribs which are circumferentially arranged at intervals.

Example 4

Referring to fig. 9 to 10, the present embodiment is different from embodiment 3 in that a plurality of lower flame holding grooves 52 are opened at the top of the annular base 5, each lower flame holding groove 52 is arranged in a radial direction and its radially inner end communicates with the through hole 51, and each lower flame holding groove 52 has a width of 0.8 to 2mm in the circumferential direction and a depth of 0.8 to 1.5mm in the vertical direction, so that a flame separation phenomenon is prevented from occurring in an unstable annular flame formed at the upper annular flame groove 321 by the plurality of upper flame holding grooves 151.

In other embodiments, instead of the lower flame holding groove 52, a plurality of flame holding holes arranged at intervals in the circumferential direction are provided in the circumferential wall of the annular base 5, each of the flame holding holes being arranged in the radial direction and having a radially inner end communicating with the through hole 51.

What has been described above is merely some embodiments of the present utility model. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit of the utility model.

Claims

1. A fire lid assembly for a cooktop, comprising:

a lower fire cover (1) provided with a central hole (11) for the fuel gas to pass through, wherein the peripheral wall of the lower fire cover (1) is provided with an ignition hole group communicated with the central hole (11); and

the upper fire cover (2) is arranged at the top of the lower fire cover (1), the upper fire cover (2) and the central hole (11) are surrounded to form a gas mixing cavity (31), an upper annular fire groove (321) for gas to pass through is formed between the bottom of the upper fire cover (2) and the top of the lower fire cover (1), and the radial inner end of the upper annular fire groove (321) is communicated with the gas mixing cavity (31).

2. The fire cover assembly for a kitchen range according to claim 1, characterized in that the upper annular fire groove (321) has a width of 0.8-2 mm in the vertical direction.

3. The fire cover assembly for a kitchen range according to claim 1 or 2, characterized in that the upper annular fire groove (321) is adjustable in width in the vertical direction.

4. The fire cover assembly for a kitchen range according to claim 1 or 2, characterized in that the upper and/or lower groove wall surfaces of the upper annular fire groove (321) are arranged obliquely from inside to outside and upwards, and the inclination angle of the upper and/or lower groove wall surfaces is 30-70 °.

5. The fire cover assembly for a kitchen range according to claim 1, wherein an outwardly extending cap peak (23) is fixedly arranged at the upper end or the top outer edge of the outer side wall of the upper fire cover (2), and the cap peak (23) is positioned right above the ignition hole group; and/or the number of the groups of groups,

the top of the upper fire cover (2) is provided with an upward-opening liquid containing cavity (241) and an overflow port (242), and the overflow port (242) is communicated with the liquid containing cavity (241) and is used for discharging overflow liquid in the liquid containing cavity (241).

6. The fire cover assembly for a kitchen range according to claim 1, characterized in that the lower fire cover (1) is provided with a flame stabilizing structure positioned below the upper annular fire groove (321) and/or a mounting part suitable for being matched and inserted with a burner is arranged at the bottom of the lower fire cover (1).

7. The fire cover assembly for a kitchen range according to claim 6, wherein the flame stabilizing structure is a flame stabilizing hole, a plurality of flame stabilizing holes are circumferentially arranged at intervals are formed in the peripheral wall of the lower fire cover (1) or the upper fire cover (2), and each flame stabilizing hole is radially arranged and the radially inner end of each flame stabilizing hole is communicated with the gas mixing cavity (31); or,

the flame stabilizing structure is an upper flame stabilizing groove (151), a plurality of upper flame stabilizing grooves (151) are formed in the top or the bottom of the lower flame cover (1), or a plurality of upper flame stabilizing grooves (151) are formed in the bottom of the upper flame cover (2), and each upper flame stabilizing groove (151) is arranged in the radial direction, and the radial inner end of each upper flame stabilizing groove is communicated with the air mixing cavity (31).

8. The fire cover assembly for a kitchen range according to claim 7, wherein the width of the upper flame holding groove (151) in the circumferential direction is 0.8-2 mm, and the depth of the upper flame holding groove (151) in the vertical direction is 0.8-1.5 mm.

9. The fire cover assembly for a kitchen range according to claim 1, wherein an inwardly extending boss (13) is fixedly arranged on the inner annular wall of the lower fire cover (1), a positioning part (22) is fixedly arranged at the position of the upper fire cover (2) corresponding to the boss (13), and the positioning part (22) is riveted with the boss (13) or connected and fixed through a connecting piece (4).

10. The fire cover assembly for a kitchen range according to any one of claims 1 or 2 or 5-9, further comprising an annular base (5), said annular base (5) being arranged at the bottom of said lower fire cover (1) and being fixedly connected to said lower fire cover (1) and/or said upper fire cover (2), said annular base (5) having a through hole (51) communicating with said central hole (11).

11. The fire cover assembly for a kitchen range according to claim 10, characterized in that the lower fire cover (1) bottom abuts the annular base (5) top; or, a lower annular fire groove (322) is formed between the bottom of the lower fire cover (1) and the top of the annular base (5), and the radial inner end of the lower annular fire groove (322) is communicated with the through hole (51) and/or the central hole (11).

12. The fire cover assembly for a kitchen range according to claim 11, characterized in that the width of the lower annular fire groove (322) in the vertical direction is 0.8-2 mm, and the width of the lower annular fire groove (322) is larger than the width of the upper annular fire groove (321).

13. The fire cover assembly for a kitchen range according to claim 11, characterized in that a plurality of lower flame holding grooves (52) are formed in the top of the annular base (5), each lower flame holding groove (52) being arranged radially and the radially inner end thereof being communicated with the through hole (51); or,

the side wall of the annular base (5) is provided with a plurality of flame stabilizing holes which are arranged at intervals along the circumferential direction, and the flame stabilizing holes in the annular base (5) are communicated with the through holes (51).

14. The fire cover assembly for a kitchen range according to claim 13, characterized in that the width of the lower flame holding groove (52) in the circumferential direction is 0.8-2 mm, and the depth of the lower flame holding groove (52) in the vertical direction is 0.8-1.5 mm.

15. The fire cover assembly for a kitchen range according to claim 10, characterized in that an inwardly extending lug (53) is fixedly arranged on the inner annular wall of the annular base (5), and the lug (53) is riveted or connected and fixed with the upper fire cover (2) and/or the lower fire cover (1) through a connecting piece (4); and/or the bottom of the annular base (5) is provided with a mounting part which is suitable for being matched and spliced with the furnace end.