Anti-stall axial flow fan and control method thereof

Abstract

The invention relates to the field of axial flow fans, and discloses an anti-stall axial flow fan and a control method thereof.On one hand, the anti-stall axial flow fan comprises an inlet air bellow, an inlet flue, a diffusion barrel and a motor are connected to the inlet air bellow, and a turbine is arranged at the joint of the inlet air bellow and the diffusion barrel; the circulating flow path comprises a backflow channel, and a regulating valve and a flow detection device which are arranged on the backflow channel; the performance stabilizing device can lead the reverse airflow located at the top of the turbine into the inlet air box again; and the control device is used for controlling switches of the regulating valve and the performance stabilizing device. On the other hand, the invention provides a control method of the anti-stall axial flow fan, the control method is applied to the anti-stall axial flow fan and comprises the following steps that when the flow detected by the flow detection device is larger than a first preset value, the adjusting valve is closed, and the performance stabilizing device does not work; and when the flow detected by the flow detection device is smaller than a second preset value, the adjusting valve is opened, and the performance stabilizing device is started.

Description

Technical Field

[0001] The invention relates to the technical field of axial flow fans, and in particular to an anti-stall axial flow fan and a control method thereof. Background Art

[0002] Axial induced draft fans are used in power plant boiler systems to extract flue gas from the boiler to maintain negative pressure in the boiler. They are widely used in large coal-fired units due to their high efficiency and small rotor inertia.

[0003] However, in recent years, the peak load regulation of the units has been more frequent, and it is impossible to ensure that the axial flow induced draft fan can always operate under normal conditions. Axial flow fans have a stall zone, especially in low flow conditions, which is more likely to cause stall, which can easily bring certain risks during operation. Especially with the ultra-low emission transformation of the units, the system resistance that the axial flow induced draft fan needs to overcome will be further increased, increasing the risk of fan stall. Summary of the invention

[0004] The purpose of the present invention is to overcome the fan stall problem existing in the prior art and to provide an anti-stall axial flow fan and a control method thereof, which has the effect of improving stability and reducing the risk of stall.

[0005] In order to achieve the above object, the present invention provides an anti-stall axial flow fan, comprising: An inlet wind box, to which an inlet flue, a diffuser and a motor are connected, the inlet flue, the diffuser and the motor are located on different sides of the inlet wind box, and an impeller is provided at the connection between the inlet wind box and the diffuser; The circulation flow path includes a return flow channel, a regulating valve and a flow detection device arranged on the return flow channel. One end of the return flow channel is connected to the top of the diffuser tube, and the other end is connected to the inlet flue. The flow detection device is located at one end adjacent to the diffuser tube. A performance stabilizing device is provided on the side of the inlet wind box adjacent to the impeller, and the performance stabilizing device can reintroduce the reverse airflow at the top of the impeller into the inlet wind box; Control device: The control device is used to control the switch of regulating valves and performance stabilizing devices.

[0006] In some embodiments, the performance stabilizing device includes a partition and a rotating plate rotatably arranged on the partition, the outer edge of the partition is pressed against the inner wall of the inlet bellows, a plurality of penetrating reflux holes are opened on the outer periphery of the partition, the reflux holes are axially arranged toward the impeller, and an adjusting hole connected to the reflux hole is opened on the rotating plate, the reflux hole and the adjusting hole correspond one-to-one, and the control device can control the rotating plate to rotate or stop.

[0007] In some embodiments, the rotating plate is coaxial with the partition, a rotating shaft is coaxially inserted through the rotating plate and the partition, and the outer edge of the rotating plate is slidably connected to the inner wall of the inlet bellows.

[0008] In some embodiments, pressing blocks are provided at both ends of the rotating shaft, one of the pressing blocks presses against the partition plate, and the other pressing block presses against the rotating plate.

[0009] In some embodiments, both the partition plate and the rotating plate are provided with penetrating air flow holes, which are interconnected so that the air flow in the inlet wind box flows toward the impeller.

[0010] In some embodiments, the reflow holes are evenly spaced along the circumference of the partition plate, and the adjustment holes are evenly spaced along the circumference of the rotating plate.

[0011] In some embodiments, the control device includes a driving member and a connecting member, the connecting member is connected to the rotating plate, and the control device drives the rotating plate to rotate by pulling the connecting member through the driving member.

[0012] In some embodiments, a check valve is provided on the return passage.

[0013] In some embodiments, a plurality of brackets are disposed at the bottom of the diffusion cylinder.

[0014] On the other hand, the present invention provides a control method for an anti-stall axial flow fan, which is applied to the above-mentioned anti-stall axial flow fan, and comprises the following steps: When the flow rate detected by the flow detection device is greater than or equal to the first preset value, the regulating valve is closed and the performance stabilization device does not operate; When the flow rate detected by the flow detection device is less than or equal to the second preset value, the regulating valve is opened and the performance stabilization device is started.

[0015] Through the above technical solution, during the operation of the axial flow fan, the gas is diffused to the diffuser through the inlet flue, the inlet wind box, and the impeller. The flow detection device on the diffuser detects the flow condition in real time. When the flow value is detected to be lower than the preset value, the control system opens the regulating valve and the performance stabilization device to adjust the flow. This application controls and adjusts the flow of the axial flow fan from multiple directions through the joint operation of the circulating flow path and the performance stabilization device, thereby improving the stability of the axial flow fan and reducing the risk of stalling. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of an anti-stall axial flow fan in an embodiment of the present application; Figure 2 is a schematic diagram of the structure of the performance stabilization device in the embodiment of the present application; Figure 3 It is an exploded diagram of the performance stabilizing device in the embodiment of the present application.

[0017] Description of Reference Numerals 1. Inlet bellows; 2. Inlet flue; 3. Diffuser; 4. Motor; 5. Impeller; 6. Circulation path; 61. Return path; 62. Regulating valve; 63. Flow detection device; 64. Check valve; 7. Performance stabilizing device; 71. Partition; 711. Return hole; 72. Rotating plate; 721. Regulating hole; 73. Rotating shaft; 731. Pressing block; 74. Airflow hole; 8. Control device; 9. Bracket. DETAILED DESCRIPTION

[0018] The following is a further detailed description of the implementation methods of the present application in conjunction with the accompanying drawings and examples. The detailed descriptions of the following examples and the accompanying drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application. The present application can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0019] The present application provides these embodiments to make the present application thorough and complete, and to fully express the scope of the present application to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0020] It should be noted that, in the description of this application, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing this application 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, and therefore cannot be understood as a limitation on this application. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0021] In addition, the words "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean vertical in the strict sense, but is within the tolerance range. "Parallel" does not mean parallel in the strict sense, but is within the tolerance range. "Include" or "comprising" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0022] It should also be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0023] All terms used in this application have the same meaning as those understood by those of ordinary skill in the art to which this application belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, such as general dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0024] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0025] Reference Figure 1 On the one hand, the present invention provides an anti-stall axial flow fan, comprising An inlet wind box 1, to which an inlet flue 2, a diffuser 3 and a motor 4 are connected. The inlet flue 2, the diffuser 3 and the motor 4 are located on different sides of the inlet wind box 1, respectively. An impeller 5 is provided at the connection between the inlet wind box 1 and the diffuser 3; The circulation flow path 6 includes a return flow channel 61, a regulating valve 62 and a flow detection device 63 arranged on the return flow channel 61. One end of the return flow channel 61 is connected to the top of the diffuser 3, and the other end is connected to the inlet flue 2. The flow detection device 63 is located at one end adjacent to the diffuser 3; Performance stabilizing device 7: A performance stabilizing device 7 is provided on the side of the inlet wind box 1 adjacent to the impeller 5, and the performance stabilizing device 7 can reintroduce the reverse airflow at the top of the impeller 5 into the inlet wind box 1; The control device 8 is used to control the switching of the regulating valve 62 and the performance stabilizing device 7 .

[0026] The present application discloses an anti-stall axial flow fan, comprising an inlet wind box 1, a circulation flow path 6, a performance stabilizing device 7 and a control device 8.

[0027] The top of the inlet wind box 1 is connected to the inlet flue 2, which is in communication with the inlet wind box 1. The inlet flue 2 is in the shape of a long cylinder, and the end of the inlet flue 2 near the inlet wind box 1 is a narrow opening. A diffusion cylinder 3 is connected to one side of the inlet wind box 1. The diffusion cylinder 3 is in the shape of a cylinder, and the diameter of the diffusion cylinder 3 gradually increases in the direction away from the inlet wind box 1. An impeller 5 is provided at the connection between the inlet wind box 1 and the diffusion cylinder 3, and the airflow in the inlet wind box 1 flows to the diffusion cylinder 3 through the impeller of the impeller 5. A motor 4 is connected to the side of the inlet wind box 1 away from the diffusion cylinder 3.

[0028] A circulation flow path 6 is provided between the diffusion cylinder 3 and the inlet flue 2. The circulation flow path 6 includes a return flow path 61. One end of the return flow path 61 is provided at the top of the diffusion cylinder 3 and communicates with the inner cavity of the diffusion cylinder 3. The other end is connected to the side of the inlet flue 2 and communicates with the inner cavity of the inlet flue 2. A flow detection device 63 is provided at one end of the return flow path 61 adjacent to the diffusion cylinder 3. The flow detection device 63 can be a flow meter. A regulating valve 62 is provided on the return flow path 61. The flow control device 8 and the regulating valve 62 are both electrically connected to the control device 8.

[0029] The performance stabilizing device 7 is located at a side of the inlet wind box 1 adjacent to the impeller 5 , and is capable of reintroducing the reverse airflow at the top of the impeller 5 into the inlet wind box 1 .

[0030] The control device 8 controls the opening or closing of the regulating valve 62 and the performance stabilizing device 7 according to the detection data of the flow detection device 63 .

[0031] During the operation of the axial flow fan, the gas is diffused toward the diffuser 3 through the inlet flue 2, the inlet wind box 1, and the impeller 5. The flow detection device 63 on the diffuser 3 detects the flow condition in real time. When the flow value is detected to be lower than the preset value, the control system opens the regulating valve 62 and the performance stabilizing device 7 to adjust the flow. The present application controls and adjusts the flow of the axial flow fan from multiple directions through the joint operation of the circulating flow path 6 and the performance stabilizing device 7, thereby improving the stability of the axial flow fan and reducing the risk of stalling.

[0032] Reference Figure 2 and Figure 3 In some embodiments, the performance stabilizing device 7 includes a partition 71 and a rotating plate 72 rotatably arranged on the partition 71. The outer edge of the partition 71 is pressed against the inner wall of the inlet wind box 1. A plurality of penetrating reflow holes 711 are provided on the outer periphery of the partition 71. The reflow holes 711 are axially arranged toward the impeller 5. An adjusting hole 721 connected to the reflow hole 711 is provided on the rotating plate 72. The reflow holes 711 correspond one to one with the adjusting holes 721. The control device 8 can control the rotating plate 72 to rotate or stop.

[0033] In some embodiments, the performance stabilizing device 7 includes a partition 71 and a rotating plate 72. The partition 71 and the rotating plate 72 are both circular. The diameter of the partition 71 is greater than the diameter of the rotating plate 72. The outer edge of the partition 71 is tightly pressed against the inner wall of the inlet wind box 1. The rotating plate 72 is rotatably arranged on the partition 71. The partition 71 is provided with a plurality of through-going reflow holes 711. The reflow holes 711 are opened toward the impeller of the impeller machine 5, connecting the inlet wind box 1 and the impeller machine 5. The rotating plate 72 is provided with an adjusting hole 721 connected with the reflow hole 711. The reflow hole 711 corresponds to the adjusting hole 721 one by one. The adjusting hole 721 is located on the outer periphery of the rotating plate 72. Under the drive of the control device 8, the rotating plate 72 rotates, the reflow hole 711 is staggered with the adjusting hole 721, and the rotating plate 72 can cover the reflow hole 711.

[0034] Reference Figure 2 and Figure 3 In some embodiments, the rotating plate 72 is coaxial with the partition plate 71 , and a rotating shaft 73 is coaxially inserted through the rotating plate 72 and the partition plate 71 , and the outer edge of the rotating plate 72 is slidably connected to the inner wall of the inlet bellows 1 .

[0035] In some embodiments, the rotating plate 72 is coaxial with the partition plate 71, and a rotating shaft 73 is coaxially inserted through the rotating plate 72 and the partition plate 71. The outer periphery of the rotating plate 72 rotates relative to the inner wall of the inlet bellows 1, and the rotating shaft 73 serves to fix the position of the rotating plate 72.

[0036] Reference Figure 2 and Figure 3 In some embodiments, both ends of the rotating shaft 73 are provided with clamping blocks 731 , wherein one clamping block 731 presses against the partition plate 71 , and the other clamping block 731 presses against the rotating plate 72 .

[0037] In some embodiments, both ends of the rotating shaft 73 are provided with a pressing block 731, wherein one pressing block 731 presses against the partition 71, and the other pressing block 731 presses against the rotating plate 72. The two pressing blocks 731 limit the partition 71 and the rotating plate 72 to prevent the rotating plate 72 from deflecting or falling off during rotation, thereby improving stability.

[0038] Reference Figure 2 and Figure 3 In some embodiments, both the partition plate 71 and the rotating plate 72 are provided with penetrating air flow holes 74 , and the air flow holes 74 are interconnected, so that the air flow in the inlet wind box 1 flows to the impeller 5 .

[0039] In some embodiments, a penetrating air flow hole 74 is opened in the middle of the partition 71 and the rotating plate 72. There are two air flow holes 74 on the partition 71 and the rotating plate 72. The two air flow holes 74 are respectively located on both sides of the rotating axis 73 and are symmetrical about the rotating axis 73. The air flow holes 74 located at the same position on the partition 71 and the rotating plate 72 are connected to each other, so that the air flow in the inlet wind box 1 flows to the impeller of the impeller 5, thereby ensuring the normal flow of the air flow.

[0040] Reference Figure 2 and Figure 3 In some embodiments, the reflow holes 711 are evenly spaced apart along the circumference of the partition plate 71 , and the adjustment holes 721 are evenly spaced apart along the circumference of the rotating plate 72 .

[0041] In some embodiments, the return holes 711 are evenly arranged at intervals along the circumference of the partition 71, and the adjustment holes 721 are evenly arranged at intervals along the circumference of the rotating plate 72. The evenly arranged return holes 711 and adjustment holes 721 are conducive to the convenience of adjustment. The rotating plate 72 only needs to rotate a certain angle to determine the current connection status of the return holes 711 and the adjustment holes 721, and the evenly arranged return holes 711 facilitate the uniformity of the reverse airflow backflow, thereby improving the flow regulation effect.

[0042] Reference Figure 2 and Figure 3 In some embodiments, the control device 8 includes a driving member and a connecting member, the connecting member is connected to the rotating plate 72, and the control device 8 drives the rotating plate 72 to rotate by pulling the connecting member through the driving member.

[0043] In some embodiments, the control device 8 includes a driving member and a connecting member, and the connecting member is sleeved on the outer periphery of the rotating plate 72. The driving member pulls the connecting member to drive the rotating plate 72 to rotate. The connecting member can be a transmission belt, and the driving member can be a stepper motor. One end of the transmission belt is wound around the rotating plate 72, and the other end is wound around the driving shaft of the stepper motor. The rotation of the stepper motor drives the transmission belt to rotate, thereby driving the rotating plate 72 to rotate relative to the partition 71, so that the reflux hole 711 is connected or separated from the adjustment hole 721. Other different driving members and connecting members can also be used.

[0044] The control system also includes a control console, and the regulating valve 62 and the stepper motor are both electrically connected to the control console, and the control console can control the opening or closing of the regulating valve 62 and the stepper motor.

[0045] Reference Figure 1 In some embodiments, a check valve 64 is provided on the return channel 61 .

[0046] In some embodiments, a check valve 64 is provided on the return channel 61. The check valve 64 is located on the side of the return channel 61 adjacent to the diffuser 3. The check valve 64 prevents the gas from flowing back into the impeller stall zone, thereby further improving stability.

[0047] Reference Figure 1 In some embodiments, a plurality of brackets 9 are provided at the bottom of the diffusion tube 3 .

[0048] In some embodiments, a plurality of brackets 9 are provided at the bottom of the diffuser tube 3 to stabilize the diffuser tube 3 and prevent the diffuser tube 3 from shifting or shaking during the operation of the fan.

[0049] In a preferred embodiment of an anti-stall axial flow fan provided by the present application, the fan comprises an inlet wind box 1, a circulation flow path 6, a performance stabilizing device 7 and a control device 8, wherein: The top of the inlet wind box 1 is connected to the inlet flue 2, which is in communication with the inlet wind box 1. The inlet flue 2 is in the shape of a long cylinder, and the end of the inlet flue 2 near the inlet wind box 1 is a narrow opening. A diffusion cylinder 3 is connected to one side of the inlet wind box 1. The diffusion cylinder 3 is in the shape of a cylinder, and the diameter of the diffusion cylinder 3 gradually increases in the direction away from the inlet wind box 1. An impeller 5 is provided at the connection between the inlet wind box 1 and the diffusion cylinder 3, and the airflow in the inlet wind box 1 flows to the diffusion cylinder 3 through the impeller of the impeller 5. A motor 4 is connected to the side of the inlet wind box 1 away from the diffusion cylinder 3.

[0050] A circulation flow path 6 is provided between the diffusion cylinder 3 and the inlet flue 2. The circulation flow path 6 includes a return flow path 61. One end of the return flow path 61 is provided at the top of the diffusion cylinder 3 and communicates with the inner cavity of the diffusion cylinder 3. The other end is connected to the side of the inlet flue 2 and communicates with the inner cavity of the inlet flue 2. A flow detection device 63 is provided at one end of the return flow path 61 near the diffusion cylinder 3. The flow detection device 63 can be a flow meter. A regulating valve 62 is provided on the return flow path 61. The flow control device 8 and the regulating valve 62 are both electrically connected to the control device 8. A check valve 64 is provided on the return flow path 61. The check valve 64 is located on the side of the return flow path 61 near the diffusion cylinder 3.

[0051] The performance stabilizing device 7 is located at a side of the inlet wind box 1 adjacent to the impeller 5 , and is capable of reintroducing the reverse airflow at the top of the impeller 5 into the inlet wind box 1 .

[0052] The performance stabilizing device 7 includes a partition 71 and a rotating plate 72 . The partition 71 and the rotating plate 72 are both circular. The diameter of the partition 71 is greater than the diameter of the rotating plate 72 . The outer edge of the partition 71 is tightly pressed against the inner wall of the inlet bellows 1 , and the rotating plate 72 is rotatably set on the partition 71 .

[0053] The rotating plate 72 is coaxial with the partition plate 71, and a rotating shaft 73 is coaxially inserted through the rotating plate 72 and the partition plate 71, and the outer periphery of the rotating plate 72 rotates relative to the inner wall of the inlet wind box 1. Both ends of the rotating shaft 73 are provided with pressing blocks 731, one of which presses against the partition plate 71, and the other presses against the rotating plate 72, and the two pressing blocks 731 limit the partition plate 71 and the rotating plate 72.

[0054] The partition plate 71 is provided with a plurality of through-going reflow holes 711, which are opened toward the impeller of the impeller 5 and connect the inlet wind box 1 and the impeller 5. The rotating plate 72 is provided with regulating holes 721 connected with the reflow holes 711, the reflow holes 711 correspond to the regulating holes 721 one by one, and the regulating holes 721 are located on the outer periphery of the rotating plate 72. The reflow holes 711 are evenly arranged at intervals along the circumference of the partition plate 71, and the regulating holes 721 are evenly arranged at intervals along the circumference of the rotating plate 72. Under the drive of the control device 8, the rotating plate 72 rotates, the reflow holes 711 and the regulating holes 721 are staggered, and the rotating plate 72 can cover the reflow holes 711.

[0055] A penetrating air flow hole 74 is provided in the middle of the partition 71 and the rotating plate 72. There are two air flow holes 74 on each of the partition 71 and the rotating plate 72. The two air flow holes 74 are respectively located on both sides of the rotating shaft 73 and are symmetrical about the rotating shaft 73. The air flow holes 74 located at the same position on the partition 71 and the rotating plate 72 are connected to each other, so that the air flow in the inlet wind box 1 flows to the impeller of the impeller 5.

[0056] The control device 8 controls the opening or closing of the regulating valve 62 and the performance stabilizing device 7 according to the detection data of the flow detection device 63. It includes a driving member and a connecting member, the connecting member is sleeved on the outer periphery of the rotating plate 72, the driving member pulls the connecting member to drive the rotating plate 72 to rotate, the connecting member can be a transmission belt, and the driving member can be a stepping motor, one end of the transmission belt is wound around the rotating plate 72, and the other end is wound around the driving shaft of the stepping motor, the rotation of the stepping motor drives the transmission belt to rotate, thereby driving the rotating plate 72 to rotate relative to the partition 71, so that the reflux hole 711 is connected or separated from the regulating hole 721. It also includes a control console, and the regulating valve 62 and the stepping motor are both electrically connected to the control console.

[0057] During the operation of the axial flow fan, the airflow is diverged to the diffuser 3 through the inlet flue 2, the inlet wind box 1, and the impeller 5. The flow detection device 63 on the diffuser 3 detects the flow condition in real time. When the flow value is detected to be lower than the preset value, the control system opens the regulating valve 62 and the stepper motor. The opened regulating valve 62 makes the return channel 61 open. The airflow in the diffuser 3 flows into the inlet flue 2 through the return channel 61 and flows to the impeller 5 again. The started stepper motor drives the rotating plate 72 to rotate through the transmission belt, so that the return hole 711 is connected with the regulating hole 721. Part of the airflow flowing to the diffuser 3 flows back from the return hole 711 to the inlet wind box 1 and continues to flow, thereby adjusting the flow. The present application controls and adjusts the flow of the axial flow fan from multiple directions through the joint operation of the circulating flow path 6 and the performance stabilizing device 7, thereby improving the stability of the axial flow fan and reducing the risk of stalling.

[0058] On the other hand, the present invention provides a control method for an anti-stall axial flow fan, which is applied to the above-mentioned anti-stall axial flow fan, and comprises the following steps: When the flow rate detected by the flow detection device 63 is greater than or equal to the first preset value, the regulating valve 62 is closed and the performance stabilizing device 7 does not operate; When the flow rate detected by the flow detection device 63 is less than or equal to the second preset value, the regulating valve 62 is opened and the performance stabilizing device 7 is started.

[0059] By setting the circulation flow path 6 and the performance stabilizing device 7, when the flow rate detected by the flow detection device 63 is greater than or equal to the first preset value, the regulating valve 62 is closed, the performance stabilizing device 7 does not operate, and the axial flow fan operates normally. When the flow rate detected by the flow detection device 63 is less than or equal to the second preset value, the regulating valve 62 is opened, the performance stabilizing device 7 is started, and the air flow rate is adjusted. The control method of the anti-stall axial flow fan can effectively prevent the axial flow fan from stalling and improve the stability of the axial flow fan during operation.

[0060] So far, the various embodiments of the present application have been described in detail. In order to avoid obscuring the concept of the present application, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed herein.

[0061] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. An anti-stall axial flow fan, characterized in that: include An inlet wind box (1), the inlet wind box (1) being connected to an inlet flue (2), a diffuser (3) and a motor (4), the inlet flue (2), the diffuser (3) and the motor (4) being located on different sides of the inlet wind box (1), respectively, and an impeller (5) being provided at the connection between the inlet wind box (1) and the diffuser (3); a circulation flow path (6), the circulation flow path (6) comprising a return flow channel (61), a regulating valve (62) and a flow detection device (63) arranged on the return flow channel (61), one end of the return flow channel (61) being connected to the top of the diffuser tube (3), and the other end being connected to the inlet flue (2), and the flow detection device (63) being located at one end adjacent to the diffuser tube (3); A performance stabilizing device (7) is arranged on a side of the inlet wind box (1) adjacent to the impeller (5), and the performance stabilizing device (7) is capable of reintroducing the reverse airflow at the top of the impeller (5) into the inlet wind box (1); A control device (8), the control device (8) being used to control the switching of the regulating valve (62) and the performance stabilizing device (7).

2. The anti-stall axial flow fan according to claim 1, characterized in that: The performance stabilizing device (7) comprises a partition (71) and a rotating plate (72) rotatably arranged on the partition (71); the outer edge of the partition (71) is tightly abutted against the inner wall of the inlet wind box (1); a plurality of through-going return holes (711) are provided on the outer peripheral edge of the partition (71); the return holes (711) are axially arranged toward the impeller (5); the rotating plate (72) is provided with an adjusting hole (721) connected to the return holes (711); the return holes (711) correspond one to one with the adjusting holes (721); and the control device (8) can control the rotating plate (72) to rotate or stop.

3. The anti-stall axial flow fan according to claim 2, characterized in that: The rotating plate (72) is coaxial with the partition plate (71), a rotating shaft (73) is coaxially inserted through the rotating plate (72) and the partition plate (71), and the outer edge of the rotating plate (72) is slidably connected to the inner wall of the inlet wind box (1).

4. The anti-stall axial flow fan according to claim 3, characterized in that: Both ends of the rotating shaft (73) are provided with pressing blocks (731), one of the pressing blocks (731) is pressed against the partition plate (71), and the other of the pressing blocks (731) is pressed against the rotating plate (72).

5. The anti-stall axial flow fan according to claim 2, characterized in that: The partition plate (71) and the rotating plate (72) are both provided with penetrating air flow holes (74), and the air flow holes (74) are interconnected, so that the air flow in the inlet wind box (1) flows toward the impeller (5).

6. The anti-stall axial flow fan according to claim 2, characterized in that: The reflow holes (711) are evenly spaced and arranged along the circumference of the partition plate (71), and the adjustment holes (721) are evenly spaced and arranged along the circumference of the rotating plate (72).

7. The anti-stall axial flow fan according to claim 2, characterized in that: The control device (8) comprises a driving member and a connecting member, the connecting member being connected to the rotating plate (72), and the control device (8) drives the rotating plate (72) to rotate by pulling the connecting member through the driving member.

8. The anti-stall axial flow fan according to any one of claims 1 to 7, characterized in that: A check valve (64) is provided on the return flow channel (61).

9. The anti-stall axial flow fan according to any one of claims 1 to 7, characterized in that: A plurality of brackets (9) are arranged at the bottom of the diffusion cylinder (3).

10. A control method for an anti-stall axial flow fan, characterized in that: The anti-stall axial flow fan applied to any one of claims 1 to 9 comprises the following steps: When the flow rate detected by the flow detection device (63) is greater than or equal to a first preset value, the regulating valve (62) is closed and the performance stabilization device (7) does not operate; When the flow rate detected by the flow detection device (63) is less than or equal to a second preset value, the regulating valve (62) is opened and the performance stabilization device (7) is started.

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