CN107120313B

CN107120313B - Novel bladeless fan

Info

Publication number: CN107120313B
Application number: CN201710383663.XA
Authority: CN
Inventors: 胡辉
Original assignee: Xiaolu Technology Chongqing Co ltd
Current assignee: Xiaolu Technology Chongqing Co ltd
Priority date: 2017-05-26
Filing date: 2017-05-26
Publication date: 2023-06-20
Anticipated expiration: 2037-05-26
Also published as: CN107120313A

Abstract

The invention relates to a novel bladeless fan, which comprises an air outlet ring and a base, wherein an air channel is arranged in the air outlet ring, an air inlet is formed in the side surface of the base, an air outlet is formed in the air outlet ring, a volute is arranged in the center of the base, an air inlet which is arranged adjacent to the air inlet is formed in the side surface of the volute, an air outlet of the volute is upwards arranged and communicated with the air channel, a centrifugal wind wheel is connected in the volute through a direct current motor, and a protective net is arranged between the air outlet and the air channel; a protective net is added between the air outlet and the air duct to block foreign matters from entering the air duct and prevent the air outlet from being blocked, so that the protective net has protective and safe effects; the centrifugal wind wheel structure is adopted, so that the rotating speed of the direct current motor can be greatly reduced, and the noise is effectively reduced.

Description

Novel bladeless fan

Technical Field

The embodiment of the invention relates to the field of fans of household appliances, in particular to a novel bladeless fan.

Background

At present, most bladeless fans adopt impellers as wind source driving bodies, but because of the size and shape limitation of the impellers, the wind collecting area is small, the wind quantity requirement can be met only by a motor with high rotating speed, howling is easy to occur, and in addition, the base rotating mechanism and the sealing noise reduction structure of the existing bladeless fans also need to be improved.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a novel bladeless fan which is simple and reasonable in structure, and the rotating speed of a motor can be greatly reduced by adopting a centrifugal volute wind wheel structure, so that the noise is effectively reduced, and in addition, the novel bladeless fan is provided with a sealing ring structure with a unique structural shape and a base rotating structure, so that the using effect of the whole machine is better.

In order to solve the technical problems, the invention adopts a technical scheme that: the utility model provides a novel bladeless fan, includes air-out ring and base, is equipped with the wind channel in the air-out ring, and the air intake has been seted up to the side of base, has seted up the air outlet on the air-out ring, characterized by, the spiral case is installed to the center of base, and the air inlet that sets up adjacent with the air intake is seted up to the side of spiral case, and the air exit of spiral case sets up and switches on with the wind channel, is connected with centrifugal wind wheel through direct current motor drive in the spiral case, installs the protection network between air exit and the wind channel.

The bladeless fan with the structure is characterized in that a volute is adopted to guide air, and is matched with the centrifugal wind wheel, when the centrifugal wind wheel is driven to rotate by a direct current motor, gas filled between blades on the centrifugal wind wheel rotates at a high speed along with the centrifugal wind wheel under the pushing of the blades, so that the gas obtains a large amount of energy, the gas is thrown to the outer edge of the centrifugal wind wheel under the action of high gravity force of inertia, after the pressure energy and kinetic energy of the gas are increased, the gas flows from the volute to an air outlet to enter an air duct of an air outlet ring, negative pressure is formed at an air inlet in the middle of the volute, and the gas from an air inlet is continuously sucked under the action of atmospheric pressure to be supplemented; the centrifugal wind wheel structure is adopted, so that the rotating speed of the direct current motor can be greatly reduced, and the noise is effectively reduced.

In addition, a protective net is added between the air outlet and the air duct to block foreign matters from entering the air duct and prevent the air outlet from being blocked, so that the protective net has protective and safe effects.

In addition, the direct current motor is small in size, small in occupied space, good in silencing effect and large in torque.

Preferably, the side surface of the base is symmetrically provided with two air inlets, and the air inlet is adjacent to one of the air inlets; two air inlets are arranged, so that the air inlet area is increased, and the air inlet quantity is increased.

Preferably, an air inlet net is sleeved on the outer wall of the base, and covers the air inlet; the air inlet net plays a role in protection, foreign matters, insects and the like are placed and enter from the air inlet, and meanwhile, the whole appearance of the base is more attractive.

Preferably, the bottom of the base is provided with a rotating assembly, the rotating assembly comprises a chassis and a rotating disc, an arc-shaped rack is arranged in the chassis, a motor is fixed on the rotating disc, an output shaft of the motor extends downwards and is connected with a driving gear meshed with the arc-shaped rack, the driving gear is driven by the motor to move along the arc-shaped rack, the rotating disc rotates relative to the chassis, and the base seat is arranged on the rotating disc; the motor on the rotating disc is adopted to drive the driving gear, so that the arc-shaped rack of the driving gear on the chassis is displaced, and the rotating disc can rotate relative to the chassis, and the structure is simple, reasonable and stable.

Preferably, a plurality of arc-shaped guide frames are arranged on the chassis along the circumferential direction, a plurality of sections of L-shaped buckling plates extend downwards along the circumferential direction on the bottom surface of the rotating disc, a guide chute is formed between the L-shaped buckling plates and the bottom surface of the rotating disc, an arc-shaped guide sliding plate extends on the corresponding arc-shaped guide frame, one side of the arc-shaped guide sliding plate extends into the guide chute to be matched with the guide chute, and a convex ring which is abutted against the other side of the arc-shaped guide sliding plate is also extended on the bottom surface of the rotating disc on one side of the guide chute; on the basis of the rotating structure, in order to be more stable during rotation, through the connection of the arc-shaped guide frame and the L-shaped buckling plates, the arc-shaped guide sliding plates and the guide sliding grooves on the arc-shaped guide sliding plates are mutually matched, when the rotating disc rotates relative to the chassis, the arc-shaped guide sliding plates slide along the track guide of the guide sliding grooves when the rotating disc rotates, so that the rotating disc is more stable and reliable during rotation, the convex rings on one side of the guide sliding grooves are mutually pressed against the arc-shaped guide sliding plates, the arc-shaped guide sliding plates are more uniformly stressed, the gaps between the arc-shaped guide sliding plates are reduced, the structural combination is more compact, the virtual position is smaller, the bearing force is larger, and the structural strength is effectively increased.

Preferably, an arc-shaped interval is arranged between two adjacent sections of L-shaped buckling plates, and the length of the arc-shaped guide sliding plate is longer than the distance between the two adjacent arc-shaped intervals; the arc-shaped guide sliding plate has enough length, so that the arc-shaped guide sliding plate cannot be influenced by the arc-shaped distance when sliding, the arc-shaped guide sliding plate is always matched with the two sections of L-shaped buckling plates, and the structure is more compact and stable.

Preferably, the center of the rotating disc extends downwards to form a rotating shaft, and a shaft sleeve matched with the rotating shaft is arranged on the corresponding chassis; the rotating shaft is matched with the shaft sleeve, so that the rotating disc can form rotating fit with the chassis.

Preferably, the bottom of the air outlet ring is arranged at the top of the base through an air outlet ring base, an air guide sleeve is arranged in the air outlet ring base, the upper opening of the air guide sleeve is communicated with the air duct, and the lower opening of the air guide sleeve is communicated with the air outlet of the volute;

the outer end face of the air outlet of the volute is provided with a sealing groove, a sealing ring is sleeved on the sealing groove, the top surface of the sealing ring is bent towards the inner disk of the air outlet to form an arc-shaped bent connection section, the lower opening of the air guide sleeve presses the arc-shaped bent connection section against the top surface of the air outlet, and the arc-shaped bent connection section extends into the air guide sleeve and extends upwards in an inclined manner to form an inclined section; the air guide sleeve is communicated with the bottom of the air duct, a sealing ring with a special structure is arranged between the air guide sleeve and the air outlet of the spiral case for improving tightness, the bottom end of the sealing ring is firstly fastened in a sealing groove on the outer end face of the air outlet, then the top face of the sealing ring is bent to an inner side plate to form an arc-shaped bent section, an inclined section extends upwards, the arc-shaped bent section and the inclined section are also part of the sealing ring, the bottom opening of the air guide sleeve is in sealing connection with the air outlet of the spiral case through pressing the arc-shaped bent section, the inclined section is used for sealing and wrapping the part, close to the inner end face, of the bottom of the air guide sleeve, when air flows through the inclined section at a high speed, the inclined section can compress the inner end face of the air guide sleeve, sealing performance is improved, and sealing effect is further improved.

Preferably, the arc-shaped bent connection section and the inclined section on the sealing ring are integrally connected with the sealing ring.

Preferably, the upper opening of the air guiding sleeve is larger than the lower opening; the airflow has diffusion effect and the flow speed is increased.

The embodiment of the invention has the beneficial effects that:

(1) The novel bladeless fan is characterized in that a volute is adopted to guide air, and is matched with the centrifugal wind wheel, when the centrifugal wind wheel is driven to rotate by a direct current motor, gas filled between blades on the centrifugal wind wheel rotates at a high speed along with the centrifugal wind wheel under the pushing of the blades, so that the gas obtains a large amount of energy, the gas is thrown to the outer edge of the centrifugal wind wheel under the action of high gravity, after the pressure energy and kinetic energy of the gas are increased, the gas flows from the volute to an air outlet to enter an air duct of an air outlet ring, negative pressure is formed at an air inlet in the middle of the volute, and the gas from an air inlet is continuously sucked under the action of atmospheric pressure to be supplemented.

(2) According to the novel bladeless fan, the protective net is additionally arranged between the air outlet and the air duct and used for blocking foreign matters from entering the air duct and preventing the air outlet from being blocked, so that the novel bladeless fan has the effects of protection and safety.

(3) The invention relates to a novel bladeless fan, an air outlet of a volute is communicated with the bottom of an air duct, a sealing ring with a special structure is arranged between the air outlet of the volute and the air outlet of the air duct for improving tightness, the bottom end of the sealing ring is firstly fastened and fixed in a sealing groove on the outer end face of the air outlet, then the top face of the sealing ring is bent towards an inner side disc to form an arc-shaped bent section, an inclined section extends upwards in an inclined mode, the arc-shaped bent section and the inclined section are also part of the sealing ring, the arc-shaped bent section is used for enabling the bottom opening of the air guide sleeve to form sealing connection with the air outlet of the volute through pressing the arc-shaped bent section, the inclined section is used for sealing and wrapping the part, close to the inner end face, of the bottom of the air guide sleeve, and when air flows through the inclined section at a high speed, the inclined section can compress the inner end face of the air guide sleeve, sealing performance is improved, and sealing effect is further improved.

(4) The invention relates to a novel bladeless fan, which adopts a motor on a rotating disc to drive a driving gear to enable the driving gear to displace on an arc rack on a chassis, so that the rotating disc can rotate relative to the chassis, and the bladeless fan has a simple, reasonable and stable structure.

(5) According to the novel bladeless fan, when the rotating disc rotates relative to the chassis, the arc-shaped guide sliding plate slides along the track guide of the guide sliding groove when the rotating disc rotates, so that the rotating disc is more stable and reliable in rotation, the convex ring added on one side of the guide sliding groove and the arc-shaped guide sliding plate are mutually pressed against each other, the gap between the support and the support is reduced, the structural combination is more compact, the virtual position is smaller, the bearing of larger gravity is realized, and the structural strength is effectively increased.

(6) The novel bladeless fan adopts the centrifugal wind wheel structure, so that the rotating speed of a direct current motor can be greatly reduced, and the noise is effectively reduced; and the direct current motor has small volume, small occupied space, good silencing effect and large output torque.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which the figures of the drawings are not to be taken in a limiting sense, unless otherwise indicated.

Fig. 1 is an exploded view of the structure of the present invention.

Fig. 2 is a cross-sectional view of the structure of the present invention.

Fig. 3 is a cross-sectional view of the base of the present invention.

Fig. 4 is an exploded view of the structure of the rotating disc and the chassis of the present invention.

Fig. 5 is a sectional view showing the structure of the combination of the rotating disc and the chassis according to the present invention.

Fig. 6 is an enlarged view at B in fig. 5.

Fig. 7 is a schematic view of the structure of the rotating disk in the invention.

Fig. 8 is an enlarged view at a in fig. 3.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

In order that the invention may be readily understood, a more particular description thereof will be rendered by reference to specific embodiments that are illustrated in the appended drawings.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As shown in fig. 1 to 8, a novel bladeless fan comprises an air outlet ring 1 and a base 2, wherein an air channel 101 is arranged in the air outlet ring 1, an air inlet 201 is formed in the side surface of the base 2, and an air outlet 102 is formed in the air outlet ring 1, and the novel bladeless fan is characterized in that a volute 3 is installed in the center of the base 2, an air inlet 301 which is adjacently arranged with the air inlet 201 is formed in the side surface of the volute 3, an air outlet 302 of the volute 3 is upwards arranged and communicated with the air channel 101, a centrifugal wind wheel 5 is connected in the volute 3 through a direct current motor 4 in a driving mode, and a protective screen 6 is installed between the air outlet 302 and the air channel 101.

The bladeless fan adopting the structure is characterized in that the volute 3 is adopted for guiding air, the centrifugal wind wheel 5 is matched with the effect of the centrifugal wind wheel, when the centrifugal wind wheel 5 is driven to rotate by the direct current motor 4, gas filled between the blades 501 on the centrifugal wind wheel 5 rotates at a high speed along with the centrifugal wind wheel, so that the gas obtains a large amount of energy, the gas is thrown to the outer edge of the centrifugal wind wheel 5 under the action of high gravity force of inertia, after the pressure energy and kinetic energy of the gas are increased, the gas flows from the volute 3 to the air outlet 302 to enter the air channel 101 of the air outlet ring 1, negative pressure is formed at the air inlet 301 in the middle of the volute 3, and the gas from the air inlet 201 is continuously sucked under the action of atmospheric pressure to be supplemented.

In addition, a protective net 6 is added between the air outlet 302 and the air duct 101 to prevent foreign matters from entering the air duct, and the air outlet is blocked by placing, so that the effects of protection and safety are achieved.

Further, two air inlets 201 are symmetrically formed on the side surface of the base 2, and an air inlet 301 is arranged adjacent to one of the air inlets 201; two air inlets 201 are arranged, so that the air inlet area is increased, and the air inlet quantity is increased.

Further, an air inlet net 7 is sleeved on the outer wall of the base 2, and the air inlet net 7 covers the air inlet 201; the air inlet net 7 plays a role in protection, foreign matters, insects and the like are placed into the base through the air inlet 201, and meanwhile, the air inlet net 7 enables the overall appearance of the base 2 to be more attractive.

Further, a rotating assembly is installed at the bottom of the base 2 and comprises a chassis 8 and a rotating disc 9, an arc-shaped rack 10 is installed in the chassis 8, a motor 11 is fixed on the rotating disc 9, an output shaft of the motor 11 extends downwards and is connected with a driving gear 12 meshed with the arc-shaped rack 10, the driving gear 12 is driven by the motor 11 to move along the arc-shaped rack 10, the rotating disc 9 rotates relative to the chassis 8, and the base 2 is arranged on the rotating disc 9; the motor 11 on the rotating disc 9 is adopted to drive the driving gear 12, so that the arc-shaped rack 10 of the driving gear 12 on the chassis 8 is displaced, and the rotating disc 9 can rotate relative to the chassis 8, and the structure is simple, reasonable and stable.

Further, a plurality of arc-shaped guide frames 13 are mounted on the chassis 8 along the circumferential direction, a plurality of sections of L-shaped buckling plates 14 are downwards extended from the bottom surface of the rotating disc 9 along the circumferential direction, a guide sliding groove 1401 is formed between each L-shaped buckling plate 14 and the bottom surface of the rotating disc 9, an arc-shaped guide sliding plate 1301 is extended on the corresponding arc-shaped guide frame 13, one side of the arc-shaped guide sliding plate 1301 extends into the guide sliding groove 1401 to be matched with the inside, and a convex ring 901 which is abutted against the other side of the arc-shaped guide sliding plate 1301 is also extended on the bottom surface of the rotating disc 9 on one side of the guide sliding groove 1401; on the basis of the above-mentioned rotating structure, in order to be more stable when rotating, through the connection of arc leading truck 13 and L row buckle board 14, make arc direction slide 1301 and direction spout 1401 on the two mutually support, when rotating disk 9 relative chassis 8 rotates, arc direction slide 1301 is when rotating disk 9 rotates, the orbit direction slip along direction spout 1401 for rotating disk 9 is more stable, reliable when rotating, moreover the bulge loop 901 that the increase of direction spout 1401 one side supports with arc direction slide 1301 each other, make arc direction slide 1301 atress more even, reduce the clearance between them, make the structure combination compacter, the virtual position is less, and can bear bigger gravity, effectively increase structural strength.

Further, an arc-shaped distance 1402 is arranged between two adjacent sections of L-shaped buckling plates 14, and the length of the arc-shaped guide sliding plate 1301 is longer than the maximum distance between the two adjacent sections of L-shaped buckling plates 1402; the arc-shaped guide sliding plate 1301 has enough length, so that the arc-shaped guide sliding plate 1301 cannot be influenced by the arc-shaped distance 1402 when sliding, the arc-shaped guide sliding plate 1301 is always matched with the two sections of L-shaped buckling plates 14, and the structure is more compact and stable.

Further, a rotating shaft 902 extends downwards from the center of the rotating disc 9, and a shaft sleeve 801 matched with the rotating shaft 902 is arranged on the corresponding chassis 8; the cooperation of the shaft 902 and the shaft sleeve 801 allows the rotating disc 9 to form a rotating fit with the chassis 8.

Further, the bottom of the air outlet ring 1 is arranged at the top of the base 2 through an air outlet ring base 103, an air guide sleeve 15 is arranged in the air outlet ring base 103, an upper opening 1501 of the air guide sleeve 15 is communicated with the air duct 101, and a lower opening 1502 of the air guide sleeve 15 is communicated with an air outlet 302 of the volute 3;

the outer end face of the air outlet 302 of the volute 3 is provided with a sealing groove 302-1, a sealing ring 16 is sleeved on the sealing groove 302-1, the top surface of the sealing ring 16 is bent towards the inner disk of the air outlet 302 to form an arc-shaped bent section 1601, the lower opening 1502 of the air guide sleeve 15 presses the arc-shaped bent section 1601 against the top surface of the air outlet 302, and the arc-shaped bent section 1601 extends into the air guide sleeve 15 and extends upwards in an inclined manner to form an inclined section 1602; the air guiding sleeve 15 is to communicate the air outlet 302 of the spiral case 3 with the bottom of the air duct 101, in order to increase the tightness, a sealing ring 16 with a special structure is arranged between the air guiding sleeve 15 and the air outlet 302 of the spiral case 3, the bottom end of the sealing ring 16 is firstly fastened in a sealing groove 302-1 on the outer end face of the air outlet 302 to be fixed, then the top surface of the sealing ring 16 is bent towards the inner side disc to form an arc-shaped bent section 1601, and an inclined section 1602 extends upwards in an inclined manner, the arc-shaped bent section 1601 and the inclined section 1602 are also part of the sealing ring 16, the arc-shaped bent section 1601 is used for enabling the lower opening 1502 of the air guiding sleeve 15 to form a sealing connection with the air outlet 302 of the spiral case 3 through pressing the arc-shaped bent section 1601, the inclined section 1602 is used for sealing and wrapping the part of the lower opening 1502 of the air guiding sleeve 15 close to the inner end face 1503, when the air flows through the inclined section 1602 at a high speed, the inclined section 1503 is compressed on the inner end face of the air guiding sleeve 15, the sealing performance is increased, and the sealing effect is further improved.

Further, the arc-shaped bending section 1601 and the inclined section 1602 on the sealing ring 16 are integrally connected with the sealing ring 16.

Further, the upper opening 1501 of the air guide sleeve 15 is larger than the lower opening 1502; the horn shape is formed, so that the airflow has a diffusion effect and the flow speed is increased.

It should be noted that the description of the present invention and the accompanying drawings illustrate preferred embodiments of the present invention, but the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, which are not to be construed as additional limitations of the invention, but are provided for a more thorough understanding of the present invention. The above-described features are further combined with each other to form various embodiments not listed above, and are considered to be the scope of the present invention described in the specification; further, modifications and variations of the present invention may be apparent to those skilled in the art in light of the foregoing teachings, and all such modifications and variations are intended to be included within the scope of this invention as defined in the appended claims.

Claims

1. The novel bladeless fan comprises an air outlet ring (1) and a base (2), wherein an air channel (101) is arranged in the air outlet ring (1), an air inlet (201) is formed in the side face of the base (2), an air outlet (102) is formed in the air outlet ring (1), the novel bladeless fan is characterized in that a volute (3) is arranged in the center of the base (2), an air inlet (301) which is adjacently arranged with the air inlet (201) is formed in the side face of the volute (3), an air outlet (302) of the volute (3) is upwards arranged and is communicated with the air channel (101), a centrifugal wind wheel (5) is connected in the volute (3) through a direct current motor (4) in a driving mode, and a protection net (6) is arranged between the air outlet (302) and the air channel (101);

an air inlet net (7) is sleeved on the outer wall of the base (2);

the bottom of the air outlet ring (1) is arranged at the top of the base (2) through an air outlet ring base (103), an air guide sleeve (15) is arranged in the air outlet ring base (103), an upper opening (1501) of the air guide sleeve (15) is communicated with the air duct (101), and a lower opening (1502) of the air guide sleeve (15) is communicated with an air outlet (302) of the volute (3);

the outer terminal surface of air exit (302) of spiral case (3) is equipped with seal groove (302-1), and the cover is equipped with sealing washer (16) on seal groove (302-1), and the top surface of sealing washer (16) has curved section (1601) that connects to the inner disc of air exit (302), and lower opening (1502) of wind-guiding sleeve (15) presses curved section (1601) to support at the top surface of air exit (302), and curved section (1601) extend into wind-guiding sleeve (15) in and upwards slope extension have slope section (1602).

2. The novel bladeless fan according to claim 1, wherein the side surface of the base (2) is symmetrically provided with two air inlets (201), and the air inlet (301) is arranged adjacent to one of the air inlets (201).

3. The novel bladeless fan according to claim 1 or 2, wherein the outer wall of the base (2) is sleeved with an air inlet net (7), and the air inlet net (7) covers the air inlet (201).

4. The novel bladeless fan according to claim 1, wherein the rotating assembly is mounted at the bottom of the base (2) and comprises a chassis (8) and a rotating disc (9), an arc-shaped rack (10) is mounted in the chassis (8), a motor (11) is fixed on the rotating disc (9), an output shaft of the motor (11) extends downwards and is connected with a driving gear (12) meshed with the arc-shaped rack (10), the driving gear (12) is driven by the motor (11) to move along the arc-shaped rack (10), the rotating disc (9) rotates relative to the chassis (8), and the base (2) is arranged on the rotating disc (9).

5. The novel bladeless fan according to claim 4, wherein a plurality of arc-shaped guide frames (13) are installed on the chassis (8) according to the circumferential direction, a plurality of sections of L-shaped buckling plates (14) are downwards extended from the bottom surface of the rotating disc (9) according to the circumferential direction, a guide sliding groove (1401) is formed between each L-shaped buckling plate (14) and the bottom surface of the rotating disc (9), an arc-shaped guide sliding plate (1301) is extended on the corresponding arc-shaped guide frame (13), one side of the arc-shaped guide sliding plate (1301) is extended into the guide sliding groove (1401) to be matched with the inside, and a convex ring (901) which is propped against the other side of the arc-shaped guide sliding plate (1301) is also extended from the bottom surface of the rotating disc (9) on one side of the guide sliding groove (1401).

6. The novel bladeless fan of claim 5, wherein an arc-shaped distance (1402) is provided between two adjacent sections of L-shaped fastening plates (14), and the length of the arc-shaped guide sliding plate (1301) is greater than the distance between two adjacent arc-shaped distances (1402).

7. The novel bladeless fan according to claim 4, wherein the center of the rotating disc (9) is downwards extended with a rotating shaft (902), and a shaft sleeve (801) matched with the rotating shaft (902) is arranged on the corresponding chassis (8).

8. The novel bladeless fan of claim 1, wherein the arcuate curved connecting segments (1601), the angled segments (1602) on the sealing ring (16) are integrally connected with the sealing ring (16).

9. The novel bladeless fan according to claim 1, wherein the upper opening (1501) of the air guiding sleeve (15) is larger than the lower opening (1502).