Centrifugal fan, range hood and control method thereof

Abstract

The present invention discloses a centrifugal fan, a range hood and a control method thereof, the centrifugal fan comprising a volute and an impeller arranged in the volute, the volute comprising two cover plates arranged at intervals, an annular wall arranged between the cover plates and an air outlet; the centrifugal fan further comprises a volute tongue assembly, the volute tongue assembly comprising a tongue, a scroll and a spring sheet, the tongue being located between the end of the annular wall and the air outlet, one end of the tongue being fixedly connected to the scroll; the scroll being rotatably connected between the two cover plates and the rotation axis being parallel to the axial direction of the impeller, the scroll being maintained in a tightened state; the spring sheet being tightly attached to the side of the tongue facing outside the volute, the portion of the tongue corresponding to the spring sheet constituting a volute tongue, the volute tongue being maintained in an arc shape by the spring sheet, one end of the spring sheet being wound in a direction parallel to the axial direction of the impeller, so that adjusting the winding amount of the end of the spring sheet can change the radius of the volute tongue and keep the radial-tongue gap unchanged during the adjustment.

Description

Technical Field

[0001] The present invention relates to a power device, in particular to a centrifugal fan, a range hood using the centrifugal fan, and a control method of the range hood. Background Art

[0002] Multi-blade centrifugal fans are widely used in various household appliances, including air conditioners, range hoods, air purifiers, and ventilation fans, due to their compact structure, high pressure coefficient, large flow coefficient, and low noise. The radius of the volute tongue and the width of the outlet throat of a multi-blade centrifugal fan significantly influence its aerodynamic performance and noise.

[0003] The volute tongue is used to prevent a small amount of gas from circulating within the fan volute. When the exhaust resistance is low, the fan outlet flows smoothly, and a small volute tongue radius facilitates outlet airflow separation, which can reduce gas circulation within the volute. At the same time, the impact area during airflow separation is small, which helps reduce noise. When the exhaust resistance is high, the fan outlet flow state is more turbulent, and a large volute tongue radius can increase the loss along the way of the outlet turbulent flow back to the inner area of the volute, and increase the pressure gradient area near the volute tongue during airflow separation, thereby improving the fan's resistance capacity and reducing noise.

[0004] The fan outlet throat width is defined as the width of the line segment formed by the projection direction of the volute thickness, passing through the center of the volute tongue, parallel to the fan volute outlet and the intersection of the volute outlet section. It directly affects the exhaust capacity of the fan. When the exhaust resistance is small, the outlet throat width is large, the internal resistance of the fan is small, the exhaust is smooth, and it is beneficial to reduce noise. When the exhaust resistance is large, the outlet throat width is small. On the one hand, the volute tongue blocks the impeller more, which can reduce the direct impact of the outlet turbulence on the impeller; on the other hand, when guiding the impeller to throw out the airflow to the outlet, the airflow is more concentrated and less dispersed, which can better resist the backflow under high resistance conditions and reduce the deterioration of the internal flow field of the volute caused by the outlet turbulence state, which is beneficial to noise reduction. However, being too small is also disadvantageous, and will also increase the internal resistance of the fan exhaust, which is not conducive to noise reduction.

[0005] Usually, once a fan is designed and processed, it is finalized. The radius of the fan tongue and the width of the outlet throat cannot be adjusted. Therefore, different resistance working conditions cannot be taken into account during use, which affects the user experience.

[0006] There are also some technologies that adjust the radial tongue gap by changing the radius of the volute tongue. For example, the Chinese patent application number 201711451180.5 discloses a volute tongue and a centrifugal fan equipped with the volute tongue. The volute tongue includes a support frame and a flexible volute tongue wall provided on the support frame to form the outer contour of the volute tongue. The support frame includes an upper support body and a lower support body provided at the root of the volute tongue, and a variable R column provided at the top of the volute tongue. The upper support body, the lower support body and the variable R column are distributed in a triangular shape, and also include a driving mechanism for driving the variable R column to rotate.

[0007] For this type of centrifugal fan, when the radius of the variable R column volute tongue is reduced, the radial tongue gap can be reduced, but at the same time, the fan outlet throat width will be reduced. The reduction in the fan outlet throat width and the reduction in the volute tongue radius and the reduction in the radial tongue gap have opposite effects on the fan performance. For a specific operating condition, if reducing the volute tongue radius and reducing the radial tongue gap are favorable, then reducing the fan outlet throat width is unfavorable; if reducing the volute tongue radius and reducing the radial tongue gap are unfavorable, then reducing the fan outlet throat width is favorable; when the radius of the variable R column volute tongue is increased, the radial tongue gap can be increased, but at the same time, the fan outlet throat width will be increased. The increase in the fan outlet throat width and the increase in the volute tongue radius and the increase in the radial tongue gap have opposite effects on the fan performance. In summary, this adjustment of the radial tongue gap will not necessarily have a beneficial effect on the fan performance. Summary of the Invention

[0008] The first technical problem to be solved by the present invention is to provide a centrifugal fan in view of the deficiencies in the above-mentioned prior art, so as to ensure that the adjustment of the volute tongue structure has a favorable effect on the performance of the centrifugal fan.

[0009] The second technical problem to be solved by the present invention is to provide a range hood using the above-mentioned centrifugal fan.

[0010] The third technical problem to be solved by the present invention is to provide a control method for the centrifugal fan.

[0011] The present invention solves the first technical problem by adopting a technical solution: a centrifugal fan comprising a volute and an impeller disposed in the volute, wherein the volute comprises two spaced-apart cover plates, an annular wall disposed between the cover plates, and an air outlet, wherein the air outlet is surrounded by the cover plates and the annular wall; the centrifugal fan is characterized in that:

[0012] The centrifugal fan further includes a volute tongue assembly, which includes a tongue portion, a scroll and a spring sheet. The tongue portion is located between the end of the annular wall and the air outlet. One end of the tongue portion is fixed to the annular wall or the cover plate, and the other end of the tongue portion is fixedly connected to the scroll.

[0013] The reel is rotatably connected between the two cover plates, and the rotation axis is parallel to the impeller axis, and the reel is kept in a tightened state;

[0014] The spring sheet is tightly attached to the side of the tongue facing the outside of the volute, and the corresponding parts of the tongue and the spring sheet constitute a volute tongue. The volute tongue is maintained in an arc shape by the spring sheet. One end of the spring sheet is fixed to the annular wall or the cover plate, and the other end of the spring sheet is wound in a direction parallel to the impeller axis, so that the winding amount of the end of the spring sheet can change the radius of the volute tongue. The wound end of the spring sheet can move linearly to keep the radial tongue gap formed between the volute tongue and the impeller unchanged.

[0015] The volute tongue radius is adjusted under the premise of ensuring that the radial tongue gap remains unchanged through structural settings. As the volute tongue radius increases, the fan outlet throat width decreases. The influence of the increased volute tongue radius and the decreased fan outlet throat width on the fan performance is consistent; as the volute tongue radius decreases, the fan outlet throat width increases. The influence of the decreased volute tongue radius and the increased fan outlet throat width on the fan performance is also consistent. There is no additional change in the volute structure size parameters during adjustment, which ensures that the structural adjustment has a favorable effect on the fan performance, so that the fan performance and noise are in the best working state under different resistance conditions, thereby improving user experience.

[0016] Furthermore, to facilitate the adjustment of the radius of the spring sheet, the volute tongue assembly also includes a first driving mechanism, which is a curling motor module. The first driving mechanism is transmission-connected to the end of the spring sheet and can change the radius of the spring sheet by adjusting the curling amount of the end of the spring sheet.

[0017] Furthermore, in order to facilitate the movement of the driving spring sheet and ensure that the radial tongue gap remains unchanged, the volute tongue assembly also includes a second driving mechanism, which is a linear driving module. The output end of the second driving mechanism is transmission-connected to the first driving mechanism, and the movement direction of the output end of the second driving mechanism is consistent with the line connecting the center of the volute tongue and the center of the impeller.

[0018] The technical solution adopted by the present invention to solve the second technical problem is: a range hood, characterized in that: the centrifugal fan as described above is applied.

[0019] The technical solution adopted by the present invention to solve the third technical problem is: a control method for the range hood as described above, characterized in that:

[0020] 1) The range hood is started and the radius of the volute tongue is restored to its initial state, at which point the radius of the volute tongue is the smallest and is R0;

[0021] 2) The centrifugal fan is started, and the input current of the centrifugal fan under the current working condition is I N ;

[0022] 3) According to the pre-stored correspondence between input current and volute tongue radius, adjust the radius of the volute tongue to I N The corresponding R N .

[0023] Preferably, the corresponding relationship between the input current of the centrifugal fan and the radius of the volute tongue is obtained by the following steps:

[0024] S1) First, the radius of the volute tongue is restored to its initial state, at which point the radius is the smallest. The radius of the volute tongue in this state is recorded as R0.

[0025] S2) Connect the centrifugal fan to the exhaust pipe and adjust the resistance at the rear end of the exhaust pipe. The given resistance values are recorded as P0, P1, P2, ..., P from small to large. N , N is the number of preset resistance values, and the input current of the centrifugal fan corresponding to each resistance is recorded as I0, I1, I2, ..., I0;

[0026] S3) The optimal radius of the volute tongue under different resistances is determined by experiment, namely R0, R1, R2, ..., R N ; The best here means that the flow rate is maximized and the noise is minimized under various resistances.

[0027] Furthermore, since the stored current value is limited, in order to facilitate each situation to correspond to a limited current value, in step 2), by detecting the actual input current I of the current centrifugal fan, when the current meets I N ≤I<I N+1 When the current input current of the centrifugal fan is determined to be I N .

[0028] To adapt to sudden changes in operating conditions, in step 3), when the change in the input current of the centrifugal fan exceeds the threshold, the volute tongue radius is automatically restored to its initial state, the current input current of the centrifugal fan is detected, and then the volute tongue radius is adjusted to the state corresponding to the current input current.

[0029] Compared with the prior art, the advantages of the present invention are: the volute tongue radius is adjusted under the premise of ensuring that the radial tongue gap remains unchanged through structural settings. When the volute tongue radius increases, the fan outlet throat width decreases accordingly. The influence of the increase in volute tongue radius and the decrease in fan outlet throat width on the fan performance is consistent; when the volute tongue radius decreases, the fan outlet throat width increases accordingly. The influence of the decrease in volute tongue radius and the increase in fan outlet throat width on the fan performance is also consistent. There is no additional change in the volute structure size parameters during adjustment, which can ensure that the structural adjustment has a favorable effect on the performance of the fan, so that the fan performance and noise are in the best working state under different resistance conditions, thereby improving user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural diagram of a centrifugal fan according to an embodiment of the present invention;

[0031] Figure 2 A cross-sectional view of a centrifugal fan according to an embodiment of the present invention (with relatively large resistance);

[0032] Figure 3 for Figure 2 A schematic diagram of the partial I enlargement;

[0033] Figure 4 Schematic diagram of a volute tongue assembly of a centrifugal fan according to an embodiment of the present invention;

[0034] Figure 5 A partial cross-sectional view of a centrifugal fan according to an embodiment of the present invention (with relatively low resistance);

[0035] Figure 6 It is a partial cross-sectional view of a centrifugal fan according to an embodiment of the present invention (initial state, no resistance). DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Since the embodiments disclosed in the present invention can be set in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features.

[0038] See also Figures 1 to 4 A centrifugal fan includes a volute 1 and an impeller 2 disposed in the volute 1. The volute 1 includes two spaced-apart cover plates 11, an annular wall 12 disposed between the cover plates 11, and an air outlet 13, wherein the air outlet 13 is surrounded by the cover plates 11 and the annular wall 12.

[0039] The centrifugal fan also includes a volute tongue assembly, which includes a tongue portion 14, a reel 15, a spring leaf 16, a first drive mechanism 17, and a second drive mechanism 18. The tongue portion 14 has a certain thickness and moderate hardness, allowing for a certain degree of deformation. Preferably, it can be made of rubber. The position of the tongue portion 14 is the same as in the prior art, located between the end of the annular wall 12 (the contour of the annular wall 12 is typically a spiral, with this end being the starting point of the spiral) and the air outlet 13. One end of the tongue portion 14 is fixed to the annular wall 12 or the cover plate 11, while the other end of the tongue portion 14 is fixedly connected to the reel 15. The reel 15 is rotatably connected between the two cover plates 11, with its axis of rotation parallel to the axial direction of the impeller 2. The reel 15 is an elastic reel that can rotate about its own axis under the action of an external force. In the absence of external force, it remains tightened, thereby achieving the purpose of adjusting the area of the tongue portion 14.

[0040] Maintaining the shape of tongue 14 relies on the tension of a spring leaf 16, which is also located between annular wall 12 and air outlet 13, abutting the side of tongue 14 facing outward from volute 1. One end of spring leaf 16 is fixed to annular wall 12 or cover plate 11, while the other end is drivingly connected to the output end of first drive mechanism 17. The portion of tongue 14 corresponding to spring leaf 16 forms volute tongue 141, which is maintained in an arc shape by spring leaf 16. First drive mechanism 17 is a winding motor module that controls and adjusts the amount of winding of spring leaf 16 (the winding axis is parallel to the axis of impeller 2) to maintain an arc shape of varying diameters, thereby varying the radius of volute tongue 141 and the width of throat 19 (the space between volute tongue 141 and the opposite side of annular wall 12).

[0041] During the process of adjusting the radius of the volute tongue 141, the position of the first drive mechanism 17 must also be adjusted to ensure that the centrifugal fan's radial tongue clearance (the distance between the outer periphery of the impeller 2 and the volute tongue 141) remains unchanged, thereby avoiding adverse effects on fan performance and noise. The position of the first drive mechanism 17 is controlled by a second drive mechanism 18. The second drive mechanism 18 is a linear drive module, such as an electric push rod, a motor gear rack combination, etc., which is fixed to the annular wall 12 or the cover plate 11 and is transmission-connected to the first drive mechanism 17. For example, the first drive mechanism 17 can be fixed to the output end of the second drive mechanism 18 via a drive connection frame 20. The direction of movement of the output end of the second drive mechanism 18 is consistent with the line connecting the center of the volute tongue 141 and the center of the impeller 2 (the two centers are located on the same plane perpendicular to the axis of the impeller 2). In this embodiment, the second drive mechanism 18 is an electric push rod, and its direction of movement is consistent with the line connecting the center of the volute tongue 141 and the center of the impeller 2.

[0042] When the resistance is small, the first driving mechanism 17 Figure 3When the direction of the view shown in the figure is rotated clockwise to retract and the second motion mechanism 18 is retracted synchronously, the radius of the volute tongue 141 becomes smaller and the width of the fan outlet throat 19 increases; when the resistance is relatively large, the first drive mechanism 17 is in the Figure 3 When the direction of the view shown in FIG is rotated counterclockwise and expanded outward, and the second motion mechanism 18 is extended synchronously, the radius of the volute tongue 141 becomes larger and the width of the fan outlet throat 19 decreases.

[0043] When a centrifugal fan is used in a range hood and connected to a pipeline for use, a method for controlling the adjustment of the volute tongue assembly includes the following steps:

[0044] 1) Turn on the range hood and restore the radius of the snail tongue 141 to its initial state;

[0045] 2) The centrifugal fan starts, adapts to the resistance state of the pipe, and obtains the current input current of the centrifugal fan as I N ;

[0046] 3) Then, the first drive mechanism 17 and the second drive mechanism 18 are controlled to adjust the radius of the volute tongue 141 to I according to the pre-stored relationship between the input current and the radius. N Corresponding R N , so as to take into account the use of different resistance conditions.

[0047] In the above steps, the corresponding relationship between input current and radius is obtained through the following steps:

[0048] S1) First, the radius of the volute tongue 141 is restored to the initial state, at which the radius of the volute tongue 141 is the smallest and the width of the throat 19 is the largest. Figure 6 ; The radius of the volute tongue 141 in this state is recorded as R0;

[0049] S2) Connect the centrifugal fan to the exhaust pipe and adjust the resistance at the rear end of the exhaust pipe. The given resistance values are recorded as P0, P1, P2, ..., P from small to large. N , where the resistance is 0 (the optimal volute radius under this resistance is R0), and N is the number of preset resistance values; the corresponding input currents of the centrifugal fan under each resistance are recorded as I0, I1, I2, ..., I N Usually, after the centrifugal fan is finalized and the control circuit is determined, the current corresponding to different resistances is determined. Each resistance corresponds to a current. Therefore, the input current corresponding to different resistances can be obtained here.

[0050] S3) Determine the resistance (P0, P1, P2, ..., P N ) are R0, R1, R2, ..., R N ; The best here refers to the situation where the flow rate is the largest and the noise is the lowest under this working condition;

[0051] Since the input current value is limited in the stored relationship, in step 2), the actual input current I of the current centrifugal fan is detected. N ≤I<I N+1 When the current input current of the centrifugal fan is determined to be I N .

[0052] In addition, in step 3), in actual use, the input currents I0, I1, I2, ..., I N The current value can be segmented. For example, when there is no resistance, the input current may be 0.5A. As the resistance increases, the input current gradually increases to 0.55, 0.60, 0.65...1.00A, etc. In this case, the segmentation can be 0.5-0.575, 0.575-0.62... This segmentation needs to be divided according to the current range and the degree of current fluctuation corresponding to different resistances.

[0053] During use, if it is detected that the change in the input current of the centrifugal fan exceeds a threshold value, which means exceeding a preset value or jumping from one current segment interval to another, the radius of the volute tongue 141 will be automatically restored to its initial state, the current input current of the centrifugal fan will be detected and compared, and then the first drive mechanism 17 and the second drive mechanism 18 will be controlled to adjust the radius of the volute tongue 141 to the state corresponding to the current input current.

Claims

1. A centrifugal fan, comprising a volute (1) and an impeller (2) disposed in the volute (1), wherein the volute (1) comprises two spaced-apart cover plates (11), an annular wall (12) disposed between the cover plates (11), and an air outlet (13), wherein the air outlet (13) is surrounded by the cover plates (11) and the annular wall (12); and characterized in that: The centrifugal fan further comprises a volute tongue assembly, the volute tongue assembly comprising a tongue portion (14), a scroll (15) and a spring sheet (16), the tongue portion (14) being located between the end of the annular wall (12) and the air outlet (13), one end of the tongue portion (14) being fixed to the annular wall (12) or the cover plate (11), and the other end of the tongue portion (14) being fixedly connected to the scroll (15); The reel (15) is rotatably connected between the two cover plates (11) and its rotation axis is parallel to the axial direction of the impeller (2), and the reel (15) is kept in a tightened state; The spring sheet (16) is tightly attached to the side of the tongue (14) facing the outside of the volute (1); the corresponding parts of the tongue (14) and the spring sheet (16) constitute a volute tongue (141); the volute tongue (141) is maintained in an arc shape by the spring sheet (16); one end of the spring sheet (16) is fixed to the annular wall (12) or the cover plate (11); the other end of the spring sheet (16) is wound in a direction parallel to the axial direction of the impeller (2); thereby, adjusting the winding amount of the end of the spring sheet (16) can change the radius of the volute tongue (141); the wound end of the spring sheet (16) can move linearly so that the radial-tongue gap formed between the volute tongue (141) and the impeller (2) remains unchanged.

2. The centrifugal fan according to claim 1, characterized in that: The volute tongue assembly further comprises a first driving mechanism (17), which is a curling motor module. The first driving mechanism (17) is in transmission connection with the end of the spring sheet (16) and can change the radius of the spring sheet (16) by adjusting the curling amount of the end of the spring sheet (16).

3. The centrifugal fan according to claim 2, characterized in that: The volute tongue assembly further comprises a second drive mechanism (18), the second drive mechanism (18) being a linear drive module, the output end of the second drive mechanism (18) being transmission-connected to the first drive mechanism (17), and the movement direction of the output end of the second drive mechanism (18) being consistent with the line connecting the center of the volute tongue (141) and the center of the impeller (2).

4. A range hood, characterized in that: The centrifugal fan according to any one of claims 1 to 3 is used.

5. A range hood control method according to claim 4, characterized in that: 1) The range hood is started, and the radius of the volute tongue (141) is restored to the initial state, at which point the radius of the volute tongue (141) is the smallest and is R0; 2) The centrifugal fan is started, and the input current of the centrifugal fan under the current working condition is I N ; 3) According to the pre-stored corresponding relationship between the input current and the radius of the volute tongue (141), the radius of the volute tongue (141) is adjusted to I N The corresponding R N .

6. The range hood control method according to claim 5, characterized in that: The corresponding relationship between the input current of the centrifugal fan and the radius of the volute tongue (141) is obtained by the following steps: S1) First, the radius of the volute tongue (141) is restored to its initial state, at which point the radius of the volute tongue (141) is the smallest, and the radius of the volute tongue (141) in this state is recorded as R0; S2) Connect the centrifugal fan to the exhaust pipe and adjust the resistance at the rear end of the exhaust pipe. The given resistance values are recorded as P0, P1, P2, ..., P from small to large. N , N is the number of preset resistance values, and the input current of the centrifugal fan corresponding to each resistance is recorded as I0, I1, I2, ..., I N ; S3) Determine through experiments that the optimal radius of the volute tongue (141) under various resistances is R0, R1, R2, ..., R N ; The best here means that the flow rate is maximized and the noise is minimized under various resistances.

7. The range hood control method according to claim 6, characterized in that: In step 2), by detecting the actual input current I of the current centrifugal fan, when the current satisfies I N ≤I<I N+1 When the current input current of the centrifugal fan is determined to be I N .

8. The range hood control method according to claim 5, characterized in that: In step 3), when the change of the centrifugal fan input current exceeds a threshold value, the radius of the volute tongue (141) is automatically restored to an initial state, the current centrifugal fan input current is detected, and then the radius of the volute tongue (141) is adjusted to a state corresponding to the current input current.

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