CN112648664A

CN112648664A - Fume exhaust fan

Info

Publication number: CN112648664A
Application number: CN202110011546.7A
Authority: CN
Inventors: 余旭锋; 耿芳芳
Original assignee: Ningbo Fotile Kitchen Ware Co Ltd
Current assignee: Ningbo Fotile Kitchen Ware Co Ltd
Priority date: 2021-01-06
Filing date: 2021-01-06
Publication date: 2021-04-13
Anticipated expiration: 2041-01-06
Also published as: CN112648664B

Abstract

The invention relates to a range hood, which comprises a fan frame, wherein a cavity for accommodating a main fan is arranged in the fan frame; the smoke collecting cover is arranged at the bottom of the fan frame, a smoke collecting cavity is formed on the inner side of the smoke collecting cover, a main air inlet is formed in the top of the smoke collecting cavity on the smoke collecting cover and is communicated with a cavity of the fan frame in a fluid mode, auxiliary air inlets are formed in the smoke collecting cover on two sides of the main air inlet, and auxiliary air inlet channels communicated with the auxiliary air inlets in the smoke collecting cover in the fluid mode are formed in the smoke collecting cover on two sides of the main air inlet; two auxiliary fans are arranged in the two auxiliary air inlet channels correspondingly; an auxiliary air outlet communicated with the auxiliary air inlet channel and the cavity of the fan frame is formed in the side wall of the fan frame, and the center line of the auxiliary air outlet is perpendicular to the center line of an air inlet hole of the main fan. The auxiliary airflow is prevented from interfering with the main airflow (the airflow entering from the main air inlet).

Description

Fume exhaust fan

Technical Field

The invention belongs to the technical field of range hoods, and particularly relates to a range hood.

Background

The fume exhaust fan is one kitchen appliance for purifying kitchen environment and can exhaust the waste gas produced by burning kitchen range and fume produced during cooking fast to reach the aim of purifying kitchen environment.

At present, side-suction range hoods for short-distance smoke extraction exist in the market, for example, the range hood disclosed in the Chinese invention patent with the patent number of CN201610915630.0 (with the publication number of CN106382259A) is a novel current collector and a range hood applying the current collector, and the range hood is mainly characterized in that an air inlet is close to a kitchen range, and the range hood moves downwards close to a negative pressure area to quickly absorb oil smoke, so that direct discharge of near suction without smoke leakage is realized; the other type is a top-suction type range hood, such as the range hood disclosed in the Chinese invention patent with the patent number of CN201710213082.1 (with the publication number of CN107339726A), which is mainly characterized in that the range hood is provided with a deep smoke collecting cavity and a ring suction plate, and although an air inlet of the range hood is far away from a kitchen range, the range hood can collect smoke in a large area by expanding a negative pressure area and the deep smoke collecting cavity, so that the four-side ring suction can not run the smoke.

The two kinds of range hoods are different in structure, but the design purpose focuses on how to achieve the best oil smoke absorption effect, and the design purpose is also one of the most important indexes for evaluating the range hoods. The range hood can basically meet the requirement of no smoke leakage under the working condition of a straight-line or small negative pressure public flue without a smoke channel, but under the condition of a large negative pressure public flue or external air interference, the current smoke absorption effect cannot realize no smoke leakage, and particularly, the smoke on two sides of the smoke collection cover is easy to escape, so that the problems of poor user experience of customers, complaints and the like are caused.

In order to solve the above problems, a range hood disclosed in chinese patent application with patent number CN201711023140.0 (publication number CN107575919A) includes a smoke collecting hood, the smoke collecting hood is recessed upwards to form a smoke collecting cavity, a main air inlet is arranged on the smoke collecting cavity, an auxiliary air inlet located outside the smoke collecting cavity is arranged at the lower end of the smoke collecting hood, an auxiliary smoke exhaust channel communicated with the auxiliary air inlet is arranged on the smoke collecting hood, and the range hood further includes an air extracting device capable of extracting oil smoke in the auxiliary smoke exhaust channel. When the oil smoke can not enter the main air inlet and escapes indoors, the escaped oil smoke can enter the auxiliary air inlet positioned outside the smoke collection cavity under the action of the air draft device and is exhausted outdoors through the auxiliary smoke exhaust channel communicated with the auxiliary air inlet, and the oil smoke escape prevention effect is good.

However, the range hood has the following defects: 1. the central axis of the air draft device (hereinafter, an auxiliary fan) is vertical to the central axis of the main fan, namely, the axis of the air outlet of the auxiliary fan is parallel to the central axis of the main fan, so that the interference of auxiliary entering air flow to main air flow is easily caused, and the two air flows are intersected to generate vortex to influence the performance of the range hood; 2. the patent does not disclose whether the rotating speed of the air draft device can be adjusted, if the rotating speed of the air draft device cannot be adjusted, namely the air intake is fixed, when the rotating speed of the main fan is reduced, the auxiliary air intake exceeds the air exhaust speed of the main fan, and a vortex is generated in the fan frame, so that the efficiency of the fan is reduced, the oil smoke absorption effect is reduced, and the noise is improved; 3. when a single stove operates, oil smoke is arranged on one side of a main air inlet of the oil smoke machine, only air is required to be fed from one side, air quantity on the other side is started on the two sides, and the working effect is avoided, so that the working efficiency of the whole machine is low.

Disclosure of Invention

The first technical problem to be solved by the invention is to provide a range hood which prevents the interference of the auxiliary air flow entering the auxiliary air inlet to the main air flow entering the main air inlet, aiming at the current situation of the prior art.

The second technical problem to be solved by the present invention is to provide a range hood in which the rotation speed of the auxiliary fan can be adapted to the rotation speed of the main fan, in view of the current situation of the prior art.

The third technical problem to be solved by the invention is to provide a range hood capable of realizing unilateral air intake at a main air inlet when a single stove works, aiming at the current situation of the prior art.

The technical scheme adopted by the invention for solving the first technical problem is as follows: a range hood comprises

The fan frame is internally provided with a cavity for accommodating the main fan;

the smoke collecting cover is arranged at the bottom of the fan frame, a smoke collecting cavity is formed on the inner side of the smoke collecting cover, a main air inlet is formed in the top of the smoke collecting cavity on the smoke collecting cover and is communicated with a cavity of the fan frame in a fluid mode, auxiliary air inlets are formed in the smoke collecting cover on two sides of the main air inlet, and auxiliary air inlet channels communicated with the auxiliary air inlets in the smoke collecting cover in the fluid mode are formed in the smoke collecting cover on two sides of the main air inlet;

two auxiliary fans are arranged in the two auxiliary air inlet channels correspondingly;

the method is characterized in that: and an auxiliary air outlet communicated with the auxiliary air inlet channel and the cavity of the fan frame is formed in the side wall of the fan frame, and the central line of the auxiliary air outlet is perpendicular to the central line of an air inlet hole of the main fan.

In the above scheme, the left and right sides of main air intake all is formed with supplementary air intake and supplementary inlet air passageway, main fan includes the spiral case and locates the impeller in the spiral case, the central line of supplementary air outlet extends along left right direction, main fan's fresh air inlet is seted up on the antetheca of spiral case, and the central line of fresh air inlet extends along the fore-and-aft direction, and the central line perpendicular to main fan's of supplementary air outlet central line is like this central line of fresh air inlet.

Preferably, the auxiliary air outlet is strip-shaped and extends along the front-back direction, and the length of the auxiliary air outlet is smaller than the thickness of the volute, so that on one hand, the oil smoke entering the fan frame from the auxiliary air outlet cannot interfere with the air flow entering the main fan from front to back to form a vortex; on the other hand, the air flow needs to bypass the annular wall of the volute and then enters the main fan from the front main air flow channel and the rear main air flow channel, and the auxiliary air flow enters from the lower part of the volute and can drive the oil smoke at the lower part of the volute to flow to the main air flow channel more easily.

Preferably, the auxiliary air outlet is positioned above the main air inlet, and the vertical distance between the auxiliary air outlet and the lowest point of the main air inlet is greater than 20mm, so that the interference of auxiliary air inlet on the air flow of the main fan can be reduced, and the air flow rate of the main air inlet is ensured; and the auxiliary air outlet is positioned below the volute, and the vertical distance between the auxiliary air outlet and the bottom of the volute of the main fan is more than 20mm, so that the auxiliary air outlet has a long enough distance to ensure that the auxiliary air flow is converted from the transverse air flow into the vertical air flow to enter the main fan.

Preferably, the area of the air outlet hole of the auxiliary fan is smaller than that of the auxiliary air outlet, so that the outlet resistance of the auxiliary fan is reduced, and the efficiency of the auxiliary fan is improved.

In order to facilitate the setting up supplementary air intake, supplementary air outlet and auxiliary fan, the collection petticoat pipe includes that the open cover body that is the slot-like in top and lid establish the apron in the open mouth department in top of the cover body, main air intake and supplementary air intake are all seted up on the diapire of the cover body, and the diapire of the cover body upwards sunken formation collection cigarette chamber, the lateral wall of fan frame passes the periphery that the apron extends to main air intake to the inside supplementary inlet air passageway that forms that is located the fan frame left and right sides of collection petticoat pipe, supplementary air outlet is located the collection petticoat pipe.

The technical scheme adopted by the invention for solving the second technical problem is as follows: under the condition that the rotating speed of the main fan is increased, the rotating speed of the auxiliary fan is increased; and in the state that the rotation speed of the main fan is reduced, the rotation speed of the auxiliary fan is reduced.

And the rotating speeds of the auxiliary fan and the main fan are increased or reduced in the same proportion. The auxiliary fan is adjusted in the same proportion mode to be adaptive to the flow state of the main fan, and the problems that the air inlet volume of the auxiliary fan exceeds the air outlet volume of the main fan and a vortex is formed in a fan frame can be solved; secondly, when the rotation speed of the main fan is increased, the exhaust air volume of the fan is increased, and further the required air volume in the fan frame is increased, at the moment, the rotation speed of the auxiliary fan is increased, so that the air volume entering the fan frame can be increased, the fan efficiency can be increased, and the oil smoke absorption effect can be enhanced.

The technical scheme adopted by the invention for solving the third technical problem is as follows: the main air inlet is provided with two wind shields which are arranged side by side left and right, the wind shields are rotatably arranged in the smoke collecting hood, and the rotation axis of the wind shields extends along the front-back direction.

Preferably, the auxiliary fan on the right side works in a state that the wind shield on the left side is opened; in a state where the wind deflector on the right side is opened, the auxiliary fan on the left side operates. Therefore, the oil smoke on the other side of the cooking range can be sucked in.

Preferably, the auxiliary fan is a crossflow fan.

Compared with the prior art, the invention has the advantages that: 1. according to the invention, the auxiliary air inlets positioned at the left side and the right side of the main air inlet are arranged on the smoke collection cover, and the auxiliary air outlet is arranged on the fan frame, so that the auxiliary fan can suck airflow from the auxiliary air inlets and blow the airflow into the fan frame from the auxiliary air outlets to be sucked away by the main fan, thus the smoking capability at the two sides of the smoke collection cover can be effectively enhanced, and the oil smoke is prevented from escaping at the periphery of the smoke collection cover; 2. the central line of the auxiliary air outlet is vertical to the central line of the air inlet hole of the main fan, so that the outlet airflow of the auxiliary fan (namely, the airflow entering from the auxiliary air inlet) is ensured to be under the volute, the auxiliary airflow is prevented from interfering the main airflow (the airflow entering from the main air inlet), and the phenomenon that the two airflows intersect to generate a vortex to influence the performance of the range hood is avoided; 3. when the rotating speed of the main fan is increased or reduced, the rotating speed of the auxiliary fan is increased or reduced along with the main fan, so that the working efficiency and the service life of the auxiliary fan can be improved, because the probability of left and right smoke leakage is reduced or increased when the rotating speed of the main fan is increased or reduced, and when the probability of smoke leakage is reduced, the rotating speed of the auxiliary fan can be reduced, the load of the auxiliary fan is reduced, and the service life of the auxiliary fan is prolonged; when the smoke leakage probability is increased, the rotating speed of the auxiliary fan is increased, and the auxiliary air inlet efficiency is improved; when the rotating speed of the main fan is reduced, if the air intake of the auxiliary fan exceeds the air exhaust speed of the main fan, a vortex is generated in the fan frame, so that the efficiency of the fan is reduced, the oil smoke absorption effect is reduced, and the noise is improved; 4. the two wind shields are arranged at the main air inlet, when a single cooking range is used, one wind shield can be opened to improve the negative pressure and the flow on the single side of the main air inlet, when the two cooking ranges are used simultaneously, the two wind shields are opened simultaneously, the two wind shields can be opened or closed according to different working states of the cooking ranges, and the working efficiency of the range hood is greatly improved.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a cross-sectional view of FIG. 1;

FIG. 3 is a cross-sectional view in another direction of FIG. 1;

FIG. 4 is a cross-sectional view in another direction of FIG. 1;

FIG. 5 is a cross-sectional view in another direction of FIG. 1;

FIG. 6 is a schematic structural view of the fume collecting hood of FIG. 1;

FIG. 7 is a schematic structural view of the main blower of FIG. 1;

fig. 8 is a schematic view of the windshield of fig. 1.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

As shown in fig. 1 to 8, the range hood of the preferred embodiment includes a fan frame 1, a smoke collecting hood 3, an auxiliary fan 4, a main fan 2, and the like, and the main fan 2 may be a centrifugal fan.

The fan frame 1 is internally provided with a chamber 11 for accommodating the main fan 2; the smoke collecting cover 3 is arranged at the bottom of the fan frame 1, a smoke collecting cavity 31 is formed on the inner side of the smoke collecting cover 3, a main air inlet 32 is formed in the top of the smoke collecting cavity 31 on the smoke collecting cover 3, the main air inlet 32 is in fluid communication with the cavity 11 of the fan frame 1, auxiliary air inlets 33 are formed in the smoke collecting cover 3 on the left side and the right side of the main air inlet 32, and auxiliary air inlet channels 34 in fluid communication with the auxiliary air inlets 33 are formed in the smoke collecting cover 3 on the left side and the right side of the main air inlet 32; the auxiliary air blowers 4 are two and correspondingly arranged in the two auxiliary air inlet channels 34, and the side wall of the air blower frame 1 is provided with an auxiliary air outlet 12 communicated with the auxiliary air inlet channels 34 and the cavity 11 of the air blower frame 1.

As shown in fig. 1 to 4 and 6, in this embodiment, the two auxiliary fans 4 are cross-flow fans, the smoke collection cover 3 includes a groove-shaped cover body 35 with an open top and a cover plate 36 covering the open top of the cover body 35, a bottom wall of the cover body 35 is recessed upward to form a smoke collection cavity 31, the main air inlet 32 and the auxiliary air inlet 33 are both opened on a bottom wall of the cover body 35, the main air inlet 32 is located at a central portion of the bottom wall of the cover body 35, the auxiliary air inlets 33 are both disposed at left and right sides of the bottom wall of the cover body 35, and the auxiliary air inlets 33 may be arranged in a circular hole array or a strip hole array.

The side wall of the fan frame 1 penetrates through the cover plate 36 and extends to the periphery of the main air inlet 32, so that auxiliary air inlet channels 34 positioned at the left side and the right side of the fan frame 1 are formed inside the smoke collecting hood 3, auxiliary air outlets 12 are arranged on the left side wall and the right side wall of the fan frame 1, the auxiliary air outlets 12 are positioned in the smoke collecting hood 3, the auxiliary air inlet 33 at the left side is in fluid communication with the auxiliary fan 4 at the left side and the auxiliary air outlet 12 at the left side, the auxiliary air inlet 33 at the right side is in fluid communication with the auxiliary fan 4 at the right side and the auxiliary air outlet 12 at; and the space between the cover body 35 and the cover plate 36 is small, so that the wind speeds of the left side and the right side of the fume collecting hood 3 can be effectively increased, and the fume suction capacity is improved.

As shown in fig. 4, a fan cover 6 is disposed around the outer portion of the fan frame 1, a lower end of the fan cover 6 is connected to a top wall of the cover plate 36, an outer peripheral wall of the fan frame 1 is connected to an inner peripheral wall of the fan cover 6, so that an interlayer 61 in fluid communication with the auxiliary air intake channel 34 is formed therebetween, and a driving mechanism 62, such as an electric push rod, for driving the smoke guide plate 63 to move up and down may be disposed in the interlayer 61.

As shown in fig. 2 and 7, the main fan 2 includes a scroll casing 21 and an impeller 22 disposed in the scroll casing 21, a center line of the auxiliary air outlet 12 extends in a left-right direction, a direction of the auxiliary air flow flowing out from the auxiliary air outlet 12 is the left-right direction, an air inlet hole 23 of the main fan 2 is opened on a front wall of the scroll casing 21, and a center line of the air inlet hole 23 extends in a front-rear direction, so that the center line of the auxiliary air outlet 12 is perpendicular to the center line of the air inlet hole 23 of the main fan 2. The air outlet of the auxiliary fan 4 faces the auxiliary air outlet 12, i.e. the central line of the air outlet of the auxiliary fan 4 is perpendicular to the central line of the air inlet 23 of the main fan 2, and the central axis of the cross-flow fan is parallel to the central axis of the main fan 2. The area of the air outlet hole of the auxiliary fan 4 is smaller than that of the auxiliary air outlet 12, so that the outlet resistance of the auxiliary fan 4 is reduced, and the efficiency of the auxiliary fan 4 is improved.

The auxiliary air outlet 12 is strip-shaped and extends along the front-back direction, and the length of the auxiliary air outlet 12 is smaller than the thickness of the volute 21, so that on one hand, the oil smoke entering the fan frame 1 from the auxiliary air outlet 12 cannot interfere with the air flow entering the main fan 2 from front to back to form vortex; on the other hand, the air flow needs to bypass the circumferential wall of the volute 21 and then enter the main fan 2 from the front main air flow channel and the rear main air flow channel, and the auxiliary air flow enters from the lower part of the volute 21, so that the oil smoke at the lower part of the volute 21 can be driven to flow to the main air flow channel more easily.

In addition, the auxiliary air outlet 12 is positioned above the main air inlet 32, and the vertical distance between the auxiliary air outlet 12 and the lowest point of the main air inlet 32 is greater than 20mm, so that the interference of auxiliary air inlet on the air flow of the main fan 2 can be reduced, and the air flow velocity of the main air inlet 32 can be ensured; and the auxiliary air outlet 12 is located below the volute 21, and the vertical distance from the auxiliary air outlet 12 to the bottom of the volute 21 of the main fan 2 is greater than 20mm, so that the auxiliary air outlet 12 has a long enough distance to ensure that the auxiliary air flow is converted from the transverse air flow into the vertical air flow and enters the main fan 2.

Under the state that the rotating speed of the main fan 2 is increased, the rotating speed of the auxiliary fan 4 is increased; in the state where the rotation speed of the main fan 2 is reduced, the rotation speed of the auxiliary fan 4 is reduced. In this embodiment, the rotation speeds of the auxiliary fan 4 and the main fan 2 are increased or decreased in the same proportion. For example, the rotating speed of the main fan 2 is increased by 2 times, and the rotating speed of the auxiliary fan 4 is also increased by 2 times; the rotation speed of the main fan 2 is reduced by 2 times, and the rotation speed of the auxiliary fan 4 is also reduced by 2 times.

The auxiliary fan 4 can adapt to the flow state of the main fan 2 in a manner of adjusting in the same proportion, and firstly, the problems that the air intake of the auxiliary fan 4 exceeds the air exhaust volume of the main fan 2 and a vortex is formed in the fan frame 1 can be solved; secondly, when the rotation speed of the main fan 2 is increased, the exhaust air volume of the fan is increased, and further the air volume required in the fan frame 1 is increased, at the moment, the rotation speed of the auxiliary fan 4 is increased, so that the air volume entering the fan frame 1 can be increased, the fan efficiency can be increased, and the oil smoke absorption effect can be enhanced.

As shown in fig. 4 and 5, two wind deflectors 5 arranged side by side left and right are arranged at the main air inlet 32, the wind deflectors 5 are rotatably arranged in the smoke collecting hood 3, the rotation axis of the wind deflectors 5 extends in the front-rear direction, and the wind deflectors 5 can rotate under the action of a driving piece 51 (such as a motor). The auxiliary fan 4 on the right side works in the state that the wind shield 5 on the left side is opened; in a state where the wind deflector 5 on the right side is opened, the auxiliary fan 4 on the left side operates.

After the kitchen range transmits a signal to the range hood, the range hood realizes different working modes according to the kitchen range signal, when a left (right) kitchen range works, the left (right) wind shield 5 at the main air inlet 32 is controlled to be opened, left (right) air inlet is realized, the negative pressure and the flow of a single side are promoted, the auxiliary fan 4 at the right (left) side of the fan frame 1 is opened simultaneously, auxiliary air inlet is realized, and part of escaping oil smoke from the other side of the main air inlet 32 is sucked in a supplementing way. When controlling the kitchen and opening simultaneously, control deep bead 5 and open in step, and open auxiliary fan 4 on fan frame 1 left and right sides, realize the main air inlet and control the full operating mode state of auxiliary air inlet. The single-side working efficiency of the range hood can be greatly improved when the range is in different working states.

The term "fluid communication" as used herein refers to a spatial relationship between two components or portions (hereinafter collectively referred to as a first portion and a second portion, respectively), i.e., a fluid (gas, liquid or a mixture of both) can flow along a flow path from the first portion and/or be transported to the second portion, and may be a direct communication between the first portion and the second portion, or an indirect communication between the first portion and the second portion via at least one third element, such as a fluid channel, e.g., a pipe, a channel, a duct, a flow guide, a hole, a groove, or a chamber that allows a fluid to flow through, or a combination thereof.

Claims

1. A range hood comprises

The fan frame (1) is internally provided with a chamber (11) for accommodating the main fan (2);

the exhaust fume collecting hood is characterized by comprising an exhaust fume collecting hood (3) arranged at the bottom of the fan frame (1), a fume collecting cavity (31) is formed on the inner side of the exhaust fume collecting hood (3), a main air inlet (32) is formed in the top of the fume collecting cavity (31) on the exhaust fume collecting hood (3), the main air inlet (32) is communicated with a cavity (11) of the fan frame (1) in a fluid mode, auxiliary air inlets (33) are formed in the two sides of the main air inlet (32) on the exhaust fume collecting hood (3), and auxiliary air inlet channels (34) communicated with the auxiliary air inlets (33) in a fluid mode are formed in the two sides of the main air inlet (32) inside the exhaust fume collecting hood (;

two auxiliary fans (4) are correspondingly arranged in the two auxiliary air inlet channels (34);

the method is characterized in that: the side wall of the fan frame (1) is provided with an auxiliary air outlet (12) communicated with the auxiliary air inlet channel (34) and the cavity (11) of the fan frame (1), and the central line of the auxiliary air outlet (12) is perpendicular to the central line of the air inlet hole (23) of the main fan (2).

2. The range hood of claim 1, wherein: the left and right sides of main air intake (32) all is formed with supplementary air intake (33) and supplementary inlet air passageway (34), impeller (22) in main fan (2) include spiral case (21) and locate spiral case (21), the central line of supplementary air outlet (12) extends along controlling the direction, air inlet (23) of main fan (2) are seted up on the antetheca of spiral case (21), and the central line of air inlet (23) extends along the fore-and-aft direction.

3. The range hood of claim 2, wherein: the auxiliary air outlet (12) is strip-shaped and extends along the front-back direction, and the length of the auxiliary air outlet (12) is smaller than the thickness of the volute (21).

4. The range hood of claim 2, wherein: the auxiliary air outlet (12) is positioned above the main air inlet (32), and the vertical distance between the auxiliary air outlet (12) and the lowest point of the main air inlet (32) is more than 20 mm; the auxiliary air outlet (12) is positioned below the volute (21), and the vertical distance between the auxiliary air outlet (12) and the bottom of the volute (21) of the main fan (2) is greater than 20 mm.

5. The range hood of claim 2, wherein: the area of the air outlet of the auxiliary fan (4) is smaller than that of the auxiliary air outlet (12).

6. The range hood of claim 2, wherein: collection petticoat pipe (3) are established at the uncovered apron (36) in the top of the cover body (35) including the open groove-shaped cover body (35) that is in top and lid, main air intake (32) and supplementary air intake (33) are all seted up on the diapire of the cover body (35), and the diapire of the cover body (35) is upwards sunken to form collection smoke chamber (31), the lateral wall of fan frame (1) passes apron (36) and extends to the periphery of main air intake (32) to the inside supplementary inlet air passageway (34) that are located the fan frame (1) left and right sides that form of collection petticoat pipe (3), supplementary air outlet (12) are located collection petticoat pipe (3).

7. The range hood according to any one of claims 1 to 6, wherein: under the condition that the rotating speed of the main fan (2) is increased, the rotating speed of the auxiliary fan (4) is increased; and when the rotating speed of the main fan (2) is reduced, the rotating speed of the auxiliary fan (4) is reduced.

8. The range hood of claim 7, wherein: the rotating speeds of the auxiliary fan (4) and the main fan (2) are increased or reduced in the same proportion.

9. The range hood according to any one of claims 1 to 6, wherein: main air intake (32) department is equipped with two deep bead (5) that set up side by side about, deep bead (5) rotate to be set up in collection petticoat pipe (3), the axis of rotation of deep bead (5) extends along the fore-and-aft direction.

10. The range hood of claim 9, wherein: the auxiliary fan (4) on the right side works in the state that the wind shield (5) on the left side is opened; the left auxiliary fan (4) operates in a state where the right wind deflector (5) is open.