A volute structure of a centrifugal fan

Abstract

The present invention relates to a volute structure of a centrifugal fan, including a volute tongue, wherein the volute tongue has a volute tongue inner wall, and is characterized in that: the volute tongue has a closed cavity, a hole is provided on the volute tongue inner wall for airflow to enter the cavity, and a sound collector capable of detecting noise level and a sound generator capable of playing sound are provided in the cavity. The volute tongue of the present invention has a closed cavity, and during the use of the centrifugal fan, airflow can enter the cavity through the hole on the volute tongue inner wall, and the sound collector of the cavity can collect noise signals and transmit them to a controller, and the controller calculates a noise reduction frequency signal based on the collected signal and controls the sound generator to play the corresponding noise reduction accordingly, thereby playing an active noise reduction role. The structure solves the vortex problem at the volute tongue, thereby reducing fan noise and improving fan efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of range hoods, and in particular to a volute structure of a centrifugal fan. Background Art

[0002] Household range hoods use multi-blade centrifugal fans for air intake and exhaust. The fan is generally composed of a volute, a motor, an impeller, etc. The tongue-shaped protrusion in the volute is called the volute tongue, and its main function is to separate the flowing gas and prevent the gas from circulating in the volute. Due to the high gas pressure and complex flow near the volute tongue, the flow noise and rotation noise generated near the volute tongue are the main noise sources of the centrifugal fan. Reducing the noise near the volute tongue can significantly reduce the noise of the range hood.

[0003] The Chinese patent application "A fan volute for a range hood" (application number: CN201610111243.1) with application publication number CN105526193A discloses a structure, which includes a volute tongue, which includes a volute tongue inner wall, and the volute tongue forms a closed cavity, in which at least one longitudinal partition is arranged along the axial direction of the volute, and a plurality of radial partitions are arranged along the axial direction perpendicular to the volute, and the longitudinal partition and the radial partition divide the cavity into a plurality of independent closed silencing cavities, and a hole is opened on the inner wall portion of the volute tongue corresponding to each silencing cavity. The above structure divides the cavity in the volute tongue into a plurality of independent closed small cavities, and the small cavities and the corresponding holes opened on the side walls form a Helmholtz resonator. According to the Helmholtz resonance principle, after the sound propagates, the sound wave close to the natural frequency of the resonator resonates with the resonator, and during the vibration process, the air column in the cavity rubs against the inner wall of the cavity to consume sound energy, thereby absorbing and reducing noise.

[0004] The above structure reduces the fan noise to a certain extent by setting up a silencer cavity. However, due to the small space at the volute tongue, the gas is difficult to be discharged at one time, and the residual gas is easy to flow back and form vortices, resulting in reduced fan efficiency and vortex noise, which in turn causes the fan to still have a large noise. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a volute structure of a centrifugal fan which can reduce fan noise and improve fan efficiency by breaking vortex through active noise reduction in view of the current status of the prior art.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: a volute structure of a centrifugal fan, including a volute tongue, the volute tongue having a volute tongue inner wall, characterized in that: the volute tongue has a closed cavity, the volute tongue inner wall is provided with a hole for air flow to enter the cavity, and a sound collector capable of detecting noise level and a sound generator capable of playing sound are provided in the cavity.

[0007] Preferably, the two sides of the volute tongue are respectively provided with volute tongue side plates, the outer side of the volute tongue is provided with a rear plate, the rear plate and the volute tongue side plates and the volute tongue inner wall together enclose the cavity, and the sound collector and the sound generator are arranged toward the rear plate. This structure is conducive to better noise elimination.

[0008] As an improvement, a baffle extending inward along the inner wall of the volute tongue is provided in the cavity, a narrow and long guide channel is formed between the upper part of the baffle and the corresponding inner wall of the volute tongue, the upper end of the guide channel is connected to the air outlet of the volute, the lower part of the baffle and the inner wall of the volute tongue are enclosed to form a guide cavity, and an opening for air flow to enter the guide cavity is provided on the bottom wall of the volute tongue. Preferably, a silencer cavity is formed between the baffle and the rear plate, a through hole is provided on the baffle for gas to enter the silencer cavity from the guide cavity, and the sound collector and the sound generator are provided on the baffle and located in the silencer cavity. This structure can effectively reduce gas reflux and eliminate the vortex problem.

[0009] Further improvement, the guide cavity is also provided with a guide block capable of covering or opening the opening, and the volute tongue is provided with an adjustment component capable of adjusting the opening and closing of the guide block relative to the opening according to the air volume. With this structure, when the air volume is small, the adjustment component does not work, and the conventional structure of the volute tongue meets the demand. When the air volume is large, the adjustment component drives the guide block to move under the impact of the wind flow, thereby opening the opening, playing the role of breaking the vortex and reducing gas reflux.

[0010] Preferably, the adjustment assembly includes a connecting arm, a pin and an elastic member, wherein the connecting arm is arranged at the first end of the guide block and is rotatably connected to the side wall of the volute tongue through the pin, the guide block is rotatably arranged above the opening and can float upward under the impact of wind flow to open the opening, the second end of the guide block is a rotating free end, and the elastic member enables the guide block to always maintain the tendency to cover the opening. The elastic coefficient of the elastic member can be set according to the specific performance parameters of the fan system such as wind pressure and flow, so as to adjust the closing of the opening according to the size of the wind volume and keep the fan low noise.

[0011] In order to facilitate assembly, the elastic member is a spring, the first end of which abuts against the upper surface of the connecting arm, and the second end of which abuts against the inner wall of the volute tongue above it. Preferably, a plane perpendicular to the axial arrangement of the spring is formed on the inner wall of the volute tongue above the elastic member, and the second end of the spring abuts against the plane; and a slot is provided on the upper surface of the connecting arm for the first end of the spring to be clamped therein.

[0012] Preferably, the thickness of the baffle is 1.5-2 mm, and the diameter of the through hole is 2.3-3.2 mm.

[0013] In the above-mentioned schemes, the volute also includes a volute ring wall, the volute tongue is connected to the first end of the volute ring wall, the inner wall of the volute tongue includes a first arc surface segment, a second arc surface segment and a first plane segment, the first arc surface segment is arranged close to the impeller of the centrifugal fan and its lower surface constitutes a first guide surface of the centrifugal fan, the first plane segment is arranged on the air outlet side of the volute and its inner surface constitutes a second guide surface of the centrifugal fan, and the second arc surface segment is connected between the first arc surface segment and the first plane segment.

[0014] To facilitate connection, the volute also includes a front cover plate and a rear cover plate, the volute annular wall is connected between the front cover plate and the rear cover plate, the upper edge of the volute tongue is connected to the upper edges of the front cover plate and the rear cover plate, and the lower edge of the volute tongue is connected to the first end edge of the volute annular wall and is sealed by silicone.

[0015] Preferably, the baffle includes a second plane segment and a third arc segment, the second plane segment is arranged close to the first plane segment, the upper end of the third arc segment is connected to the lower end of the second plane segment, the third arc segment is arched toward the second arc segment and the lower end is connected to the upper surface of the first arc segment. The width of the guide channel formed between the first plane segment and the second plane segment gradually decreases from bottom to top. The above structure enables the guide cavity and the narrow and long guide channel to form a structure roughly in the shape of 6, thereby playing a good role in guiding and breaking vortices.

[0016] Preferably, the lower surface of the guide block is formed as a first curved surface that arches downward, and correspondingly, the two side walls of the opening are formed as matching surfaces that can match the first curved surface. The upper surface of the guide block is formed with a second curved surface that arches upward, the curvature of the second curved surface is greater than the curvature of the first curved surface, and the connection between the first curved surface and the second curved surface is smoothly transitioned. The above structure can reduce the resistance of the guide block to the wind flow.

[0017] Compared with the prior art, the advantages of the present invention are: the volute tongue of the present invention has a closed cavity. During the use of the centrifugal fan, the airflow can enter the cavity through the holes on the inner wall of the volute tongue. The sound collector of the cavity can collect noise signals and transmit them to the controller. The controller calculates the noise reduction audio signal based on the collected signal and controls the sounder to play the corresponding noise reduction signal accordingly, thereby playing an active noise reduction role. This structure eliminates the vortex problem at the volute tongue, thereby reducing the fan noise and improving the fan efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention (equipped with an impeller);

[0019] Figure 2 is a cross-sectional view of embodiment 1 of the present invention;

[0020] Figure 3Schematic diagram of the structure of the snail tongue in Example 1 of the present invention;

[0021] Figure 4 This is a schematic diagram of the assembly structure of the guide block, the connecting arm and the elastic member in Example 2 of the present invention;

[0022] Figure 5 is a cross-sectional view of embodiment 2 of the present invention;

[0023] Figure 6 It is a cross-sectional view of the volute tongue in Example 2 of the present invention (excluding the guide block). DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings.

[0025] Embodiment 1:

[0026] like Figure 1 , 2 As shown in Figures 3 and 4, the volute structure of the centrifugal fan of this embodiment includes a volute tongue 1, a front cover plate 2, a rear cover plate 3 and a volute ring wall 4. The front cover plate 2 and the rear cover plate 3 are arranged in a front-to-back spacing, and the volute ring wall 4 is connected between the front cover plate 2 and the rear cover plate 3. The volute tongue 1 is arranged on a first end of the volute ring wall 4, and a side wall of the volute tongue 1 and the side wall opposite to the volute ring wall 4 and the front cover plate 2 and the rear cover plate 3 together enclose an air outlet 40.

[0027] The volute tongue 1 of this embodiment has a volute tongue inner wall 11, which includes a first arc surface segment 111, a second arc surface segment 112 and a first plane segment 113. The first arc surface segment 111 is arranged close to the impeller of the centrifugal fan and its lower surface constitutes the first guide surface of the centrifugal fan. The first plane segment 113 is arranged on the air outlet 40 side of the volute and its inner surface constitutes the second guide surface of the centrifugal fan. The second arc surface segment 112 is connected between the first arc surface segment 111 and the first plane segment 113. The upper edge of the volute tongue 1 of this embodiment is connected to the upper edges of the front cover plate 2 and the rear cover plate 3 by screws, and the lower edge of the volute tongue 1 is connected to the first end edge of the volute ring wall 4 by screw connection and sealed by silicone.

[0028] The volute tongue 1 of this embodiment has a closed cavity 10, and a hole 110 for airflow to enter the cavity 10 is provided on the first plane section 113 of the volute tongue inner wall 11. A sound collector 5 capable of detecting the noise level and a sound generator 6 capable of playing sound are provided in the cavity 10. A corresponding controller is also provided on the volute structure, and the controller is electrically connected with the sound collector 5 and the sound generator 6. The noise signal collected by the sound collector 5 is transmitted to the controller, and the controller calculates the required noise reduction frequency signal according to the noise signal, and controls the sound generator 6 to play the corresponding noise reduction, thereby achieving a noise reduction effect. The volute tongue 1 of this embodiment is provided with volute tongue side panels 12 on both sides, and a rear panel 17 is provided on the outer side of the volute tongue 1. The rear panel 17, the volute tongue side panels 12 and the volute tongue inner wall together enclose the cavity 10, and the sound collector 5 and the sound generator 6 are arranged toward the rear panel 17, which is conducive to eliminating noise.

[0029] Embodiment 2:

[0030] like Figure 1 , 4As shown in Figures 5 and 6, the difference between this embodiment and embodiment 1 is that: a baffle 13 extending inwardly along the inner wall of the volute tongue is provided in the cavity 10 of this embodiment, and the baffle 13 includes a second plane section 131 and a third arc section 132. The second plane section 131 is arranged close to the first plane section 113, and the upper end of the third arc section 132 is connected with the lower end of the second plane section 131. The third arc section 132 is arched toward the second arc section 112 and the lower end is connected with the upper surface of the first arc section 112. A narrow and long guide channel 14 is formed between the second plane section 131 of the baffle 13 and the first plane section 11 of the inner wall 11 of the volute tongue, and the width of the guide channel 14 gradually decreases from bottom to top. The lower part of the baffle 13 and the inner wall of the cavity 10 enclose a guide cavity 15, and an opening 1111 is provided on the first arc surface section 111 for airflow to enter the guide cavity 15. A guide block 100 is also provided in the guide cavity 15, which can cover or open the opening 1111. The lower surface of the guide block 100 is formed as a first arc surface 101 that arches downward, and correspondingly, the two side walls of the opening 1111 are formed as matching surfaces 1112 that can match the first arc surface 101. The upper surface of the guide block 100 is formed with a second arc surface 102 that arches upward, and the curvature of the second arc surface 102 is greater than the curvature of the first arc surface 101, and the connection between the first arc surface 101 and the second arc surface 102 is smoothly transitioned. This structure can reduce the resistance of the guide block 100 to the wind flow. The guide cavity 15 of this embodiment and the narrow and long guide channel 14 together form a structure roughly in the shape of 6, thereby playing a good role in guiding and breaking vortices. A silencer cavity 170 is formed between the baffle 13 and the rear plate 17. A through hole 130 is provided on the baffle 13 for gas to enter the silencer cavity 170 from the guide cavity 15. The sound collector 5 and the sound generator 6 are arranged on the baffle 13 and located in the silencer cavity 170. This structure can effectively reduce gas backflow and eliminate the vortex problem. The thickness of the baffle 13 is 1.5-2 mm, and the diameter of the through hole 130 is 2.3-3.2 mm.

[0031] In this embodiment, a guide block 100 capable of covering or opening the opening 1111 is provided in the guide cavity 15, and an adjustment component 16 capable of adjusting the opening and closing of the guide block 100 relative to the opening 1111 according to the amount of wind is provided on the volute tongue 1. The adjustment component 16 includes a connecting arm 161, a pin 162 and an elastic member 163. The connecting arm 161 is two and is respectively connected to both sides of the first end of the guide block 100. The other end of the connecting arm 161 is rotatably connected to the volute tongue side plate 12 through the pin 162, and the connection is arranged near the second arc surface section 112. The guide block 100 is rotatably arranged above the opening 1111 and can float upward under the impact of wind flow to open the opening 1111. The second end of the guide block 100 is a rotating free end, and the elastic member 163 enables the guide block 100 to always maintain the tendency of covering the opening 1111. The elastic coefficient of the elastic member 163 can be set according to the specific performance parameters of the fan system, such as the wind pressure and flow rate, so as to adjust the closing of the opening according to the wind volume and keep the fan low noise. The elastic member 163 of this embodiment is a spring, the first end of which abuts against the upper surface of the connecting arm 161, and the second end of the spring abuts against the inner wall of the volute tongue above it. A plane 114 arranged perpendicular to the axial direction of the spring is formed on the inner wall of the volute tongue above the elastic member 163, and the second end of the spring abuts against the plane 114. A slot 1611 is provided on the upper surface of the connecting arm 161 for the first end of the spring to be clamped therein.

[0032] When the volute structure of the present embodiment is used, when the fan flow rate is small, the noise is small, and the guide block 100 closes the opening 1111; when the fan flow rate is large, the backflow of gas at the volute tongue 1 increases, and the airflow impacts the guide block 100 to overcome the elastic force of the elastic member 163 and float upward, opening the opening 1111. At this time, part of the gas enters the guide cavity 15 through the opening 1111, and part of the gas entering the guide cavity 15 is directly accelerated through the narrow and long guide channel 14 and discharged from the air outlet 40, and the other part passes through the through hole 130 on the baffle 13 and enters the first cavity 170. At this time, the noise signal collected by the sound collector 5 is transmitted to the controller, and the controller calculates the required noise reduction audio signal according to the noise signal, and controls the sounder 6 to play the corresponding noise reduction, thereby achieving a noise reduction effect. This structure not only reduces noise through active noise reduction, but also realizes the secondary discharge of reflux gas, reduces gas reflux, and eliminates the vortex problem, thereby reducing fan noise and improving fan efficiency.

Claims

1. A volute structure of a centrifugal fan, comprising a volute tongue (1), wherein the volute tongue (1) has a volute tongue inner wall (11), characterized in that: The volute tongue (1) has a closed cavity (10), the inner wall (11) of the volute tongue is provided with a hole (110) for airflow to enter the cavity (10), and the cavity (10) is provided with a sound collector (5) capable of detecting noise level and a sound generator (6) capable of playing sound; The cavity (10) is provided with a baffle (13) extending inwardly along the inner wall of the volute tongue; a narrow and long guide channel (14) is formed between the upper part of the baffle (13) and the corresponding inner wall of the volute tongue; the upper end of the guide channel (14) is connected to the air outlet (40) of the volute; the lower part of the baffle (13) and the inner wall of the volute tongue form a guide cavity (15); the bottom wall of the volute tongue (1) is provided with an opening (1111) for airflow to enter the guide cavity (15); the guide cavity (15) is also provided with a guide block (100) capable of covering or opening the opening (1111); the volute tongue (1) is provided with an adjustment component (16) capable of adjusting whether the guide block (100) is opened relative to the opening (1111) according to the amount of air flow; The volute tongue (1) is provided with volute tongue side plates (12) on both sides, and a rear plate (17) is provided on the outer side of the volute tongue (1). The rear plate (17), the volute tongue side plates (12) and the inner wall of the volute tongue together enclose the cavity (10). The sound collector (5) and the sound generator (6) are arranged toward the rear plate (17). A silencer cavity (170) is formed between the baffle plate (13) and the rear plate (17). The baffle plate (13) is provided with a through hole (130) for gas to enter the silencer cavity (170) from the guide cavity (15). The sound collector (5) and the sound generator (6) are arranged on the baffle plate (13) and located in the silencer cavity (170).

2. The volute structure of the centrifugal fan according to claim 1, characterized in that: The adjustment assembly (16) comprises a connecting arm (161), a pin shaft (162) and an elastic member (163); the connecting arm (161) is arranged at the first end of the guide block (100) and is rotatably connected to the side wall of the volute tongue through the pin shaft (162); the guide block (100) is rotatably arranged above the opening (1111) and can float upward under the impact of wind flow to open the opening (1111); the second end of the guide block (100) is a rotating free end; and the elastic member (163) enables the guide block (100) to always maintain a tendency to cover the opening (1111).

3. The volute structure of the centrifugal fan according to claim 2, characterized in that: The elastic member (163) is a spring, the first end of which abuts against the upper surface of the connecting arm (161), and the second end of which abuts against the inner wall of the volute tongue above it.

4. The volute structure of the centrifugal fan according to claim 3, characterized in that: A plane (114) arranged perpendicular to the axial direction of the spring is formed on the inner wall of the volute tongue above the elastic member (163), and the second end of the spring abuts against the plane (114); a slot (1611) for the first end of the spring to be clamped therein is formed on the upper surface of the connecting arm (161).

5. The volute structure of the centrifugal fan according to claim 1, characterized in that: The thickness of the baffle (13) is 1.5 to 2 mm, and the diameter of the through hole (130) is 2.3 to 3.2 mm.

6. The volute structure of a centrifugal fan according to any one of claims 1 to 5, characterized in that: The volute structure of the centrifugal fan also includes a volute ring wall (4), the volute tongue (1) is connected to the first end of the volute ring wall (4), the volute tongue inner wall (11) includes a first arc surface segment (111), a second arc surface segment (112) and a first plane segment (113), the first arc surface segment (111) is arranged close to the impeller of the centrifugal fan and its lower surface constitutes a first guide surface of the centrifugal fan, the first plane segment (113) is arranged on the air outlet (40) side of the volute and its inner surface constitutes a second guide surface of the centrifugal fan, and the second arc surface segment (112) is connected between the first arc surface segment (111) and the first plane segment (113).

7. The volute structure of the centrifugal fan according to claim 6, characterized in that: The volute structure of the centrifugal fan further comprises a front cover plate (2) and a rear cover plate (3); the volute annular wall (4) is connected between the front cover plate (2) and the rear cover plate (3); the upper edge of the volute tongue (1) is connected to the upper edges of the front cover plate (2) and the rear cover plate (3); the lower edge of the volute tongue (1) is connected to the first end edge of the volute annular wall (4) and is sealed by silicone.

8. The volute structure of the centrifugal fan according to claim 7, characterized in that: The baffle (13) comprises a second plane section (131) and a third arc surface section (132); the second plane section (131) is arranged close to the first plane section (113); the upper end of the third arc surface section (132) is connected to the lower end of the second plane section (131); the third arc surface section (132) is arched toward the second arc surface section (112) and the lower end is connected to the upper surface of the first arc surface section (111).

9. The volute structure of the centrifugal fan according to claim 8, characterized in that: The width of the guide channel (14) formed between the first plane section (113) and the second plane section (131) gradually decreases from bottom to top.

10. The volute structure of a centrifugal fan according to any one of claims 1 to 5, characterized in that: The lower surface of the guide block (100) is formed as a first curved surface (101) that arches downward, and correspondingly, the two side walls of the opening (1111) are formed as matching surfaces (1112) that can match the first curved surface (101).

11. The volute structure of the centrifugal fan according to claim 10, characterized in that: The upper surface of the guide block (100) is formed with a second curved surface (102) that arches upwards, the curvature of the second curved surface (102) is greater than the curvature of the first curved surface (101), and the connection between the first curved surface (101) and the second curved surface (102) is smoothly transitioned.

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