A centrifugal fan and a range hood using the same

Abstract

The application discloses a centrifugal fan and a range hood applying the same. The centrifugal fan comprises an impeller, the impeller comprises a front disc and a rear disc arranged at intervals, and blades are arranged between the front disc and the rear disc. The blades are at least two and arranged at intervals along the circumference of the impeller. Two ends of the length of each blade are rotatably connected with the front disc and the rear disc respectively. Each blade comprises at least three sub-blades connected in head-to-tail mode. Two adjacent sub-blades are rotatably connected, and the rotation axis is parallel to the axis of the impeller. Thus, each sub-blade changes the profile of the blade by rotation when the impeller rotates forward or reversely, so that the blade is a forward-curved blade when the impeller rotates forward or reversely. Compared with the prior art, the centrifugal fan has the advantages that the blade can automatically adapt to the rotating speed or working condition, the blade can become a forward-curved blade no matter the impeller rotates forward or reversely, the overall working capacity is improved, the air pressure and efficiency can be improved under the condition that the size or rotating speed is unchanged, and the noise is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a power device, in particular to a centrifugal fan, and a range hood using the same. BACKGROUND

[0002] The range hood has become one of the indispensable kitchen household appliances in modern families. The range hood works by using the principle of fluid dynamics, and uses a multi-blade centrifugal fan installed inside the range hood to suck and exhaust the oil fume, and uses a filter screen to filter part of the oil particles. The multi-blade centrifugal fan includes a volute, an impeller installed in the volute, and a motor driving the impeller to rotate. When the impeller rotates, a negative pressure suction is generated at the center of the fan, which sucks the oil fume below the range hood into the fan, and the oil fume is collected and guided by the volute after being accelerated by the fan and then discharged outdoors.

[0003] Considering the flue resistance, the multi-blade centrifugal fan used in the existing range hood usually adopts a strong forward-curved impeller with a high pressure ratio to achieve higher pressure. For example, a straight connection horizontal flip type oil smoke extractor fan disclosed in Chinese Patent No. 201220327905.6 includes a casing with an air inlet and an air outlet, a volute arranged inside the casing, an impeller, and a motor connected with the impeller to drive the impeller to rotate. The impeller is designed in a strong forward-curved multi-blade type, which has the advantages of high static pressure, large flow rate, high efficiency, and low noise. For another example, a blade of a centrifugal fan disclosed in Chinese Patent No. 202210101452.3 is designed according to a strong forward-curved fan arc blade drawing method to determine the arc-shaped pressure surface profile curve of the blade.

[0004] However, such a centrifugal fan has the following problems. On the one hand, oil stains are easy to accumulate on the curved side (pressure surface) of the strong forward-curved impeller, and in the water or detergent spraying process of the self-cleaning range hood, the water or detergent cannot be sprayed to the pressure surface, resulting in continuous accumulation of oil stains, gradual filling, reduction of pressure at the same speed, and performance degradation. On the other hand, with the gradual productization of the oil throwing technology by reversing cleaning, many range hoods have the need for reverse rotation of the impeller during cleaning or when used as a circulating fan or a kitchen air conditioner all-in-one machine. However, the oil stains accumulated on the originally curved side of the normal strong forward-curved impeller cannot be effectively thrown out when the normal strong forward-curved impeller is directly reversed. Moreover, the air volume and air pressure are much lower when the impeller is reversed than when the impeller is normally rotated, and the required speed is very high to achieve the same air volume or air pressure, thereby causing high noise and failing to achieve the function of a circulating fan or an air conditioner air supply. SUMMARY

[0005] The first technical problem to be solved by the present application is to provide a centrifugal fan that can improve efficiency and reduce noise.

[0006] The second technical problem to be solved by the present application is to provide a range hood using the above-mentioned centrifugal fan.

[0007] The technical scheme adopted by the present application to solve the first technical problem is as follows: a centrifugal fan, comprising an impeller, the impeller comprising a front disc and a rear disc arranged at intervals, and blades arranged between the front disc and the rear disc, the blades having at least two and being arranged at intervals along the circumference of the impeller; characterized in that:

[0008] The two ends of each blade in length are rotationally connected with the front disc and the rear disc respectively, each blade comprises at least three head-to-tail connected sub-blades, two adjacent sub-blades are rotationally connected, and the rotation axis is parallel to the axis of the impeller, so that each sub-blade changes the profile of the blade by rotation when the impeller rotates forward or reversely, so that the blade is configured as a forward bending blade when the impeller rotates forward or reversely.

[0009] By arranging the rotationally connected sub-blades, without external power, the automatic adaptation of the rotation of the blade is realized by the balance of the inertial force and the pressure difference force of the airflow when the impeller rotates forward or reversely, that is, the blade can automatically adapt according to the rotational speed or working condition, change the profile of the blade, so that it can become a suitable forward bending blade whether it rotates forward or reversely, thereby improving the overall performance of the impeller, increasing the air pressure and efficiency under the condition of unchanged size or rotational speed, and reducing noise. After the blade is rotated in place, the automatic adaptation is mainly realized by the balance of the inertial force and the pressure difference force of the airflow when the impeller rotates forward or reversely. The pressure surface of the blade when rotating forward becomes the suction surface when rotating reversely, and the suction surface when rotating forward becomes the pressure surface when rotating reversely. Due to the switching of forward and reverse rotation, the accumulated oil stains on the pressure surface are more easily removed during rotation. In addition, the self-adaptive switching ensures the reverse air pressure, air volume and efficiency of the impeller, and effectively reduces the noise of the air volume compared with the general impeller. In addition, during reverse cleaning, the washing liquid or water can effectively contact the suction surface of the back surface of the blade, so that the cleaning is more clean.

[0010] In order to facilitate the connection of the blade and the front disc and the rear disc, and to make the profile of the blade have a greater degree of freedom, the two ends of the sub-blade at the inlet of the blade in the length direction are also rotationally connected with the front disc and the rear disc respectively.

[0011] Preferably, the profile of the total blade formed by each sub-blade is a straight line, a circular arc, a wing shape or a combination of the above shapes.

[0012] Preferably, the profile of the blade is in the shape of a wing, and the head of the wing shape of the sub-blade at the inlet of the blade faces the inside of the impeller, and the head of the wing shape of each sub-blade in turn is connected with the tail of the wing shape of the adjacent sub-blade. Thus, the thickness of the blade at the inlet side is greater than that at the outlet side, which has a certain effect on the suppression of the suction surface inlet vortex.

[0013] Further, the side of each sub-blade facing the airflow is the head of the sub-blade, and the opposite side is the tail of the sub-blade; the head and the tail of each sub-blade are in the shape of a circular arc protruding away from each other, and the circular arc of the tail of each sub-blade is larger than the circular arc of the head of the sub-blade connected to the downstream sub-blade. Thus, the connection of each sub-blade can maintain the inhibiting effect on the inlet vortex of the suction surface.

[0014] Further, the side of each sub-blade facing the airflow is the head of the sub-blade, and the opposite side is the tail of the sub-blade; the head of the sub-blade at the inlet of the blade is in the shape of an airfoil or an arc, so that the air inlet resistance can be reduced.

[0015] Preferably, the adjacent sub-blades are rotationally connected through a rotating shaft.

[0016] Further, a damping pad is arranged at the rotational connection of each sub-blade, and the damping pad is sleeved on the rotating shaft. On the one hand, the damping pad can increase the damping or elastic force to assist in balancing the adjusting force, so as to adjust the shape or angle of the blade after reaching the balance, and on the other hand, the damping pad can reduce the frequency of shape adjustment in the stable working range.

[0017] Further, the centrifugal fan is a multi-wing centrifugal fan, so that the influence of the aerodynamic performance caused by the non-smooth transition between the sub-blades can be reduced.

[0018] The technical scheme adopted by the present application to solve the second technical problem is an oil extractor, characterized in that the centrifugal fan as described above is applied.

[0019] Compared with the prior art, the present application has the advantages that: by arranging the rotationally connected sub-blades, the sub-blades can automatically adapt to the rotation or the working condition of the impeller by relying on the balance of the inertial force and the pressure difference force of the airflow during the forward rotation or the reverse rotation of the impeller, that is, the sub-blades can automatically adapt to the rotation speed or the working condition and change the profile of the sub-blades, so that the sub-blades can become suitable forward-curved sub-blades during the forward rotation or the reverse rotation, the overall performance of the impeller is improved, the wind pressure and the efficiency can be improved under the condition that the size or the rotation speed is unchanged, and the noise is reduced; after the sub-blades are rotated to the position, the automatic adaptation is mainly realized by relying on the balance of the inertial force and the pressure difference force of the airflow during the forward rotation or the reverse rotation of the impeller; the pressure surface of the sub-blade during the forward rotation becomes the suction surface during the reverse rotation, and the suction surface of the sub-blade during the forward rotation becomes the pressure surface during the reverse rotation; due to the switching between the forward rotation and the reverse rotation, the oil stains accumulated on the pressure surface are more easily removed during the rotation; and due to the self-adapting switching, the wind pressure, the wind volume, and the efficiency of the impeller during the reverse rotation are guaranteed, the noise during the reverse rotation is effectively reduced, and the washing is more clean during the reverse rotation cleaning. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1Fig. 1 is a schematic view of a centrifugal fan according to a first embodiment of the present application;

[0021] Figure 2 Fig. 2 is a front view of an impeller of the centrifugal fan according to the first embodiment of the present application (forward rotation) with a front cover hidden;

[0022] Figure 3 Fig. 3 is a partial enlarged view I of Fig. 2; Figure 2

[0023] Figure 4 Fig. 4 is a schematic view of a blade of the impeller of the centrifugal fan according to the first embodiment of the present application;

[0024] Figure 5 Fig. 5 is an exploded structural schematic view of the blade of the impeller of the centrifugal fan according to the first embodiment of the present application;

[0025] Figure 6 Fig. 6 is a front view of the impeller of the centrifugal fan according to the first embodiment of the present application (forward rotation, the blade profile is different from that of Fig. 2); Figure 2

[0026] Figure 7 Fig. 7 is a front view of the impeller of the centrifugal fan according to the first embodiment of the present application (reverse rotation) with a front cover hidden;

[0027] Figure 8 Fig. 8 is an exploded structural schematic view of a blade of an impeller of a centrifugal fan according to a second embodiment of the present application. DETAILED DESCRIPTION

[0028] The present application will be further described below in conjunction with the embodiments of the drawings.

[0029] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, since the disclosed embodiments of the present application can be arranged in different directions, so these terms indicating the direction are only as an illustration and should not be regarded as a limitation, such as "upper", "lower" do not necessarily be limited to the direction opposite or consistent with the direction of gravity. In addition, the features defined as "first", "second" can explicitly or implicitly include one or more of the features.

[0030] Embodiment One

[0031] Referring to​​Figures 1-5 A centrifugal fan, comprising an impeller 100, for the sake of clear illustration, only the impeller 100 is shown in the drawings of the present application, and the volute and the motor for driving the impeller 100 are omitted, which can be of the prior art. The centrifugal fan of the present application is a multi-blade centrifugal fan, which is mainly applied to a range hood, and of course can also be applied to occasions requiring similar power devices.

[0032] The impeller 100 comprises a front disc 1 and a rear disc 2 arranged at intervals, both of which are annular and coaxially arranged at intervals with the axis of the centrifugal fan (the axis of the impeller is coaxial), and further comprises a plurality of blades 3 arranged at intervals along the circumference of the front disc 1 (i.e. the circumference of the impeller 100) and disposed between the front disc 1 and the rear disc 2. The above structure is the impeller structure of the existing centrifugal fan, which will not be described here.

[0033] Each blade 3 comprises at least three head-to-tail split blades 31, and the adjacent two split blades are rotationally connected through a rotation shaft 32, and the rotation axis is parallel to the axis of the impeller 100. Both ends of each blade 3 in the length direction are rotationally connected with the front disc 1 and the rear disc 2 respectively, and in this embodiment, preferably, the radially innermost split blade 31, i.e. the split blade 31 at the inlet of the blade 3, both ends of which in the length direction are also rotationally connected with the front disc 1 and the rear disc 2 respectively, and the rotation axis is parallel to the axis of the impeller 100. The side of each split blade 31 facing the airflow (the inlet side of the airflow) is the head 311 of the split blade 31, and the opposite side (the outlet side of the airflow) is the tail 312 of the split blade 31. The head of the split blade 31 at the inlet of the blade 3, i.e. the radially innermost split blade 31, is preferably wing-shaped or arc-shaped facing the airflow, thereby reducing the intake resistance.

[0034] The total blade 3 composed of each split blade 31 can have a shape (profile) of ordinary straight line, circular arc or wing shape, or a mutual combination of the above shapes, because the blade of the multi-blade centrifugal fan is relatively narrow (the ratio of the inner and outer diameters is generally designed to be between 0.7 and 0.9), and therefore the partial fold line (the connection of the split blade 31) and other non-fully smooth connections in the middle have little effect on the performance of the airflow flowing through the blade compared with the blade of the ordinary centrifugal fan or the axial flow, so ordinary connection is acceptable, and there is no strict requirement for fully smooth curvature transition (even in the prior art, single blades are designed to have non-smooth transition, such as typical straight line + circular arc + straight line, or circular arc + straight line + straight line).

[0035] In this embodiment, the profile of each blade 3 is wing-shaped, and the head of the wing shape of the radially innermost split blade 31 faces the inside of the impeller 100, and the head of the wing shape of each remaining split blade 31 is sequentially connected with the tail of the wing shape of the adjacent split blade 31. In this way, the thickness of the blade 3 at the inlet side is greater than that at the outlet side, which has a certain effect on the suppression of the suction surface inlet vortex.

[0036] The head 311 and the tail 312 of each sub-blade 31 are in the shape of a circular arc protruding in a direction away from each other, and the circular arc of the tail 312 of each sub-blade 31 is larger than the circular arc of the head 311 of the sub-blade 31 located downstream thereof, where the size refers to the size of the radius of the circular arc. In this way, the connection (where the direction changes) of each sub-blade 31 maintains the inhibitory effect on the inlet vortex of the suction surface. The circular arc of the head 311 of each sub-blade 31 is larger than the circular arc of the tail 312.

[0037] The impeller 100 of the present application can be switched in forward rotation and reverse rotation, and the automatic adaptation of the rotation of the blade 3 is realized by the balance of the inertial force and the pressure difference force of the airflow when the impeller rotates forward or reversely, that is, the blade can automatically adapt according to the rotational speed or working condition, and the blade profile is changed, so that the blade can become a suitable forward-curved blade whether it rotates forward or reversely, which improves the overall performance of the impeller, and can improve the air pressure and efficiency and reduce noise without changing the size or rotational speed. After the blade 3 is rotated in place, the automatic adaptation is mainly realized by the balance of the inertial force and the pressure difference force of the airflow when the impeller rotates forward or reversely.

[0038] Referring to Figure 3 , where the arrow indicates the rotation direction of the impeller 100, F1 is the centrifugal force received by the blade 3, F2 is the airflow pressure, and F3 is the support force provided by the rotation shaft at the connection of the sub-blade 31. The centrifugal force F1 is balanced by the centripetal force and the rotation of the airflow pressure F2 and the support force F3 of the rotation shaft, because the angle and direction of the airflow pressure F2 and the support force F3 of the rotation shaft will change to a certain extent due to the change in rotational speed, but the resultant force after the overall operation is stable will balance the centrifugal force F1.

[0039] When the impeller 100 rotates forward, referring to Figure 2 and Figure 6 , it is a strong forward-curved impeller, and the blade 3 can automatically adapt according to the rotational speed or working condition, and the inlet and outlet angles and the blade profile are changed. Among them Figure 2 , the rotational speed of the impeller 100 is greater than Figure 5 indicated in the state.

[0040] When the impeller 100 reverses, referring to Figure 7 , under the action of the airflow, the blade 3 rotates relative to the front disc 1 and the rear disc 2, so that the impeller 100 is formed into a forward-curved impeller, and the pressure surface S1 (indicated in Figure 4 ) of the blade 3 when rotating forward becomes a suction surface when reversing, while the suction surface S2 (indicated in Figure 4When the rotation direction is reversed, the pressure surface of the blade 3 becomes the suction surface (as shown in the middle), and the accumulated dirt on the pressure surface is more easily removed during rotation due to the switching of the rotation direction. Moreover, the adaptive switching ensures that the reverse rotation wind pressure, wind volume, and efficiency of the impeller 100 are improved, and the wind volume noise ratio is generally reduced. In addition, when the impeller is cleaned in reverse rotation, the washing liquid or water can effectively contact the suction surface (i.e., the original pressure surface) of the back of the blade 3, and the cleaning can be more thorough.

[0041] Embodiment Two

[0042] Reference Figure 8 In this embodiment, the difference from the above-mentioned embodiment one is that a damping pad 33 (which can also be an elastic member) is arranged at the rotation connection of each sub-blade 3, and the damping pad 33 is sleeved on the rotating shaft 32. On the one hand, the damping pad 33 can increase the damping or elastic force to assist in adjusting the balance of the force, thereby adjusting the shape or angle of the blade after the balance is finally reached. On the other hand, the damping pad 33 can reduce the frequency of shape adjustment in the stable working range.

Claims

1. A centrifugal fan, comprising an impeller (100), the impeller (100) including a front disc (1) and a rear disc (2) arranged at intervals, blades (3) disposed between the front disc (1) and the rear disc (2), the blades (3) having at least two and arranged at intervals along the circumference of the impeller (100); characterized in that: Each blade (3) is rotatably connected to the front plate (1) and the rear plate (2) at both ends along its length. Each blade (3) includes at least three blades (31) connected end to end. Two adjacent blades (31) are rotatably connected, and the axis of rotation is parallel to the axis of the impeller (100). Thus, each blade (31) changes its profile by rotating when the impeller (100) rotates forward or backward, so that the blade (3) is configured as a forward-curved blade when the impeller (100) rotates forward or backward.

2. The centrifugal fan according to claim 1, characterized in that: The blade (31) at the inlet of the blade (3) is rotatably connected to the front plate (1) and the rear plate (2) at both ends in the length direction.

3. The centrifugal fan according to claim 1, characterized in that: The profile of the overall blade (3) composed of individual blades (31) is a straight line, a circular arc, an airfoil, or a combination of the above shapes.

4. The centrifugal fan according to claim 3, characterized in that: The blade (3) has an airfoil profile, and the head of the airfoil of the blade (31) at the inlet of the blade (3) faces the inside of the impeller (100). The remaining blades (31) are connected in sequence with the head of the airfoil to the tail of the airfoil of the adjacent blade (31).

5. The centrifugal fan according to claim 1, characterized in that: The side of each blade (31) facing the airflow is the head (311) of the blade (31), while the opposite side is the tail (312) of the blade (31). The head (311) and tail (312) of each blade (31) are arc-shaped protrusions in the direction away from each other, and the arc of the tail (312) of each blade (31) is larger than the arc of the head (311) of the connected downstream blade (31).

6. The centrifugal fan according to claim 1, characterized in that: The side of each blade (31) facing the airflow is the head (311) of the blade (31), while the opposite side is the tail (312) of the blade (31). The head of the blade (31) at the inlet of the blade (3) is airfoil-shaped or arc-shaped.

7. The centrifugal fan according to claim 1, characterized in that: Adjacent blades (31) are rotatably connected by a rotating shaft (32).

8. The centrifugal fan according to claim 7, characterized in that: A damping pad (33) is provided at the rotating connection of each blade (3), and the damping pad (33) is sleeved on the rotating shaft (32).

9. The centrifugal fan according to claim 1, characterized in that: The centrifugal fan is a multi-blade centrifugal fan.

10. A range hood, characterized in that: The application uses a centrifugal fan as described in any one of claims 1 to 9.

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