An axial centrifugal fan

Abstract

The application provides an axial centrifugal fan, which comprises an air inlet channel, a sand blocking ring, an outer cylinder, an inner cylinder, a guide vane, a motor and an impeller; the inner cylinder is arranged in the inner portion of the outer cylinder, and a plurality of guide vanes are arranged between the inner cylinder and the outer cylinder in a circumferential direction; the motor is arranged on the inner cylinder, and the front end of the rotating shaft of the motor is provided with the impeller; the air inlet channel is arranged at the air inlet end of the outer cylinder, the small opening end of the air inlet channel is aligned with the small opening end of the front disc of the impeller, and a gap is left between the small opening end of the air inlet channel and the small opening end of the front disc of the impeller; the sand blocking ring is arranged on the inner wall of the outer cylinder, and the sand blocking ring surrounds the large opening end of the front disc of the impeller and a gap is left between the sand blocking ring and the large opening end of the front disc of the impeller. The application can prevent sand and dust from entering the vortex area of the upper portion of the fan and causing abrasion of the inner wall of the outer cylinder.

Description

Technical Field

[0001] This invention relates to the field of fan technology, and more specifically to an axial centrifugal fan. Background Technology

[0002] Fans are an important component in ventilation and cooling applications, and their function is to provide a large flow of cooling air.

[0003] In existing axial centrifugal fans, after sand and dust are drawn in, some of the sand and dust will rotate circumferentially in the vortex zone of the fan, causing wear and abnormal noise on the inner wall of the outer cylinder. This does not help to extend the service life of the fan.

[0004] In addition, axial centrifugal fans are generally installed in the heat dissipation pipe network system. There are pipes at both the air inlet and outlet of the fan. The motor is inside the pipe network. After installation, the motor and the internal components of the fan are not visible. If the phase sequence of the external power supply wiring is inconsistent with that of the fan motor, the fan rotation direction will be inconsistent with the fan design direction, which will cause a sharp reduction in the air volume of the system and have adverse consequences for the ventilation and cooling of the system.

[0005] In conclusion, there is an urgent need for a new type of axial centrifugal fan to solve the problems existing in the current technology. Summary of the Invention

[0006] The purpose of this invention is to provide an axial centrifugal fan that addresses the problems of sand and dust rotating in the fan's vortex zone, causing wear and abnormal noise on the inner wall of the fan's outer cylinder, and the problem of a significant reduction in airflow caused by incorrect external power supply wiring phase sequence, resulting in a discrepancy between the actual rotation direction of the fan and its design rotation direction. The specific technical solution is as follows:

[0007] An axial centrifugal fan includes an air inlet duct, a sand baffle ring, an outer cylinder, an inner cylinder, guide vanes, a motor, and an impeller. The inner cylinder is disposed inside the outer cylinder, and multiple guide vanes are circumferentially spaced between them. The motor is disposed on the inner cylinder, and the impeller is mounted on the front end of the motor shaft. The air inlet duct is installed at the air inlet end of the outer cylinder, with the small opening of the air inlet duct aligned with the small opening of the front disc of the impeller, and a gap is left between them. The sand baffle ring is installed on the inner wall of the outer cylinder, and the sand baffle ring is arranged around the large opening of the front disc of the impeller, with a gap left between them.

[0008] In the preferred embodiment of the above technical solutions, the outer surface of the sand-blocking ring is 0-2mm higher than the upper contour line of the large opening end of the impeller front disc.

[0009] In the preferred embodiment of the above technical solutions, multiple baffles are arranged circumferentially on the inner wall of the outer cylinder, and the baffles are located between the sand-blocking ring and the air inlet duct.

[0010] In the preferred embodiment of the above technical solution, the length direction of the spoiler is parallel to the axial direction of the outer cylinder, and the width of the spoiler is one-tenth of the inner diameter of the outer cylinder.

[0011] In the preferred embodiment of the above technical solution, a rotary encoder is provided at the rear end of the motor shaft. The rotary encoder is used to detect the rotation direction and speed of the motor. When the rotation direction of the motor is inconsistent with the preset direction, the rotation direction of the motor is switched by an external control circuit.

[0012] In the preferred embodiment of the above technical solutions, the motor is mounted on the inner cylinder via a motor mounting flange plate; an oil injection pipeline is provided to lubricate the motor bearing; a temperature sensor is provided to monitor the temperature of the motor bearing; and a vibration velocity sensor is provided to monitor the vibration velocity value of the motor bearing.

[0013] In the preferred embodiment of the above technical solution, the outer wall of the outer cylinder is provided with a junction box and a cable outlet window. The junction box is used to install the drive power line of the motor, and the cable outlet window is used to install the cable connectors of the rotary encoder, temperature sensor, and vibration speed sensor. A maintenance window cover is detachably installed on the cable outlet window.

[0014] In the preferred embodiment of the above technical solutions, the impeller and the motor shaft are fitted with a Morse taper hole, and a shaft end nut and a locking washer are provided at the end of the shaft to prevent the impeller from detaching from the shaft.

[0015] In the preferred embodiment of the above technical solutions, the outer wall of the outer cylinder is provided with a plurality of outer cylinder reinforcing ribs along the circumferential direction; the length of the inner cylinder is less than or equal to half the length of the motor.

[0016] In the preferred embodiment of the above technical solutions, a sealing gasket is provided between the air inlet end of the outer cylinder and the air inlet duct.

[0017] The application of the technical solution of the present invention has the following beneficial effects:

[0018] This invention incorporates a baffle plate and a sand-blocking ring. The sand-blocking ring directs most of the sand and dust drawn into the fan along the airflow direction, preventing sand and dust from entering the vortex zone at the top of the fan and causing wear on the inner wall of the outer cylinder. When some small dust particles enter the vortex zone, the baffle plate prevents them from continuing to rotate along the inner wall of the outer cylinder, thus effectively preventing wear on the upper part of the inner wall of the outer cylinder. The baffle plate also improves the efficiency of the fan by breaking up the vortex.

[0019] A rotary encoder is installed at the rear end of the motor shaft to detect the motor's rotation direction and speed. When the motor's rotation direction is detected to be inconsistent with the design direction, the detection signal is transmitted to the external control circuit. The external control circuit adjusts the power phase sequence to switch the motor's rotation direction, thus solving the problem of not being able to know whether the fan's rotation direction is correct after installation.

[0020] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 This is a front view of an axial centrifugal fan;

[0023] Figure 2 This is a top view of an axial centrifugal fan;

[0024] Figure 3 yes Figure 2 A partial view along direction A;

[0025] The components are as follows: 1. Air inlet duct; 2. Sealing gasket; 3. Sand baffle ring; 4. Outer cylinder; 5. Outer cylinder reinforcing rib; 6. Inner cylinder; 7. Guide vane; 8. Oil injection pipeline; 9. Motor; 10. Rotary encoder; 11. Rear end temperature sensor; 12. Junction box; 13. Front end temperature sensor; 14. Motor mounting flange plate; 15. Impeller; 16. Shaft end nut; 17. Locking washer; 18. Maintenance window cover; 19. Cable connector; 20. Baffle. Detailed Implementation

[0026] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0028] Example:

[0029] See Figures 1-3An axial centrifugal fan includes an air inlet duct 1, a sand baffle ring 3, an outer cylinder 4, an inner cylinder 6, guide vanes 7, a motor 9, and an impeller 15. The inner cylinder 6 is disposed inside the outer cylinder 4, and multiple guide vanes 7 are circumferentially spaced between them. The motor 9 is disposed on the inner cylinder 6, and the impeller 15 is mounted on the front end of the motor 9's rotating shaft. The air inlet duct 1 is installed at the air inlet end of the outer cylinder 4, and the small opening of the air inlet duct 1 is aligned with the small opening of the front disc of the impeller 15, with a gap between them. The outer ring of the sand baffle ring 3 is installed on the inner wall of the outer cylinder 4, and the sand baffle ring 3 is arranged around the large opening of the front disc of the impeller, with a gap between them (i.e., a gap is left between the inner ring of the sand baffle ring and the large opening of the front disc).

[0030] Specifically, the guide vane is an arc-shaped guide vane, which can change the rotating airflow into airflow along the length of the outer cylinder; in this embodiment, the outer cylinder, inner cylinder and motor are arranged on the same axis.

[0031] Specifically, the impeller is a centrifugal impeller, and the impeller 15 includes a front disc, a rear disc, and blades. The front disc is funnel-shaped, and multiple blades are arranged circumferentially between the front and rear discs. The blades are arc-shaped. The air inlet duct 1 is also funnel-shaped, with its small opening fitting into the small opening of the front disc, leaving a gap of 1-4 mm between them to ensure that the impeller does not scrape against the air inlet duct during rotation. The funnel-shaped air inlet duct effectively reduces the turbulence in the airflow at the impeller 15 inlet.

[0032] Preferably, the outer surface of the sand-blocking ring is 0-2mm higher than the upper contour line of the large opening end of the impeller front disc, that is, the outer surface is flush with or slightly higher than the upper contour line; the outer surface of the sand-blocking ring refers to the side of it that is close to the air inlet, and the upper contour line of the large opening end of the impeller front disc also refers to the contour line of the side of the large opening end of the front disc that is close to the air inlet.

[0033] Preferably, a gap of 2-4mm is left between the sand-blocking ring 3 and the large end of the impeller front disc to prevent the impeller from scraping against the sand-blocking ring when rotating.

[0034] The sand-blocking ring can guide most of the sand and dust drawn into the fan out of the fan along the airflow direction, preventing sand and dust from entering the vortex zone at the top of the fan and causing wear on the inner wall of the outer cylinder. However, due to the gap between the sand-blocking ring and the impeller front disc, small particles of low-density sand and dust drawn into the fan from the outside during operation may still enter the vortex zone at the top of the fan through this gap. This causes the small particles of dust to rotate in the vortex zone, causing slight wear on the inner wall of the outer cylinder. To solve this problem, this embodiment also provides multiple baffles 20 circumferentially on the inner wall of the outer cylinder 4. The baffles 20 are located between the sand-blocking ring 3 and the air inlet duct 1. Under the obstruction of the baffles, the small particles of sand and dust rotating in the vortex zone at the top of the fan will not be able to continue rotating along the inner wall of the outer cylinder, thus effectively preventing the sand and dust from wearing on the upper part of the inner wall of the outer cylinder. The baffles can also improve the efficiency of the fan after breaking the vortex.

[0035] Furthermore, the length direction of the spoiler 20 is parallel to the axial direction of the outer cylinder, the length of the spoiler is less than or equal to the distance between the sand baffle ring and the air inlet on the outer cylinder, and the width of the spoiler 20 is one-tenth of the inner diameter of the outer cylinder (the width direction of the spoiler is in the same direction as the radial direction of the outer cylinder). This setting of the width of the spoiler will not affect the installation of the air inlet; in this embodiment, four spoilers are evenly distributed along the circumference of the outer cylinder.

[0036] See Figure 1 A rotary encoder 10 is provided at the rear end of the motor 9's shaft. The rotary encoder 10 is used to detect the motor's rotation direction and speed. Speed ​​monitoring can realize real-time display of the fan's speed. When the motor's rotation direction is inconsistent with the preset direction, the motor's rotation direction is switched through an external control circuit. Please refer to the prior art for the external control circuit. The principle of controlling the motor to switch rotation direction is common knowledge, and the external control circuit will not be described in detail in this embodiment.

[0037] By detecting the motor's rotation direction, the system can automatically switch the motor's rotation direction when an incorrect wiring causes the rotation direction to deviate from the preset direction, thus automatically returning the motor to the preset direction. Furthermore, it can be programmed to power off the fan for a certain delay before switching directions if the rotation is incorrect, ensuring that the fan speed has already decreased or stopped before switching rotation directions, thereby reducing the starting resistance of the motor during switching and restarting.

[0038] Furthermore, the motor 9 is mounted on the inner cylinder 6 via a motor mounting flange plate 14; in this embodiment, an oil injection pipe 8 is provided to lubricate the motor bearing, a temperature sensor is provided to monitor the temperature of the motor bearing, and a vibration velocity sensor is provided to monitor the vibration velocity value of the motor bearing, thereby displaying the real-time bearing temperature rise and vibration velocity value of the fan motor. Figure 1As shown, in this embodiment, the front bearing of the motor is equipped with a front oil injection line, a front temperature sensor 13 and a front vibration velocity sensor, and the rear bearing of the motor is also equipped with a rear oil injection line, a rear temperature sensor 11 and a rear vibration velocity sensor, so as to realize the monitoring of the front bearing and the rear bearing respectively.

[0039] See Figures 1-3 The outer wall of the outer cylinder 4 is provided with a junction box 12 and a cable outlet window. The junction box 12 is used to install the drive power line of the motor 9. The cable outlet window is used to install the cable connectors 19 of the rotary encoder 10, temperature sensor, and vibration speed sensor. A maintenance window cover 18 is detachably installed on the cable outlet window. After removing the maintenance window cover, simple maintenance of the fan sensor, encoder, etc. can be performed without removing the fan from the pipeline system.

[0040] Preferably, the impeller and the motor shaft are fitted with a Morse taper hole to ensure the concentricity of the impeller and the motor shaft; specifically, the rear wheel disc is provided with a Morse taper hole, the impeller is mounted on the shaft through the rear wheel disc, and the end of the shaft is provided with a shaft end nut 16 and a retaining washer 17 to prevent the impeller from detaching from the shaft.

[0041] Furthermore, the outer wall of the outer cylinder 4 is provided with a plurality of outer cylinder reinforcing ribs 5 along the circumferential direction, which can effectively increase the structural strength of the outer cylinder; the length of the inner cylinder 6 is less than or equal to half the length of the motor, so that the airflow inside the outer cylinder can effectively cool the motor.

[0042] Furthermore, a sealing gasket 2 is provided between the air inlet end of the outer cylinder 4 and the air inlet duct 1; the outer cylinder is a cylindrical structure with flanges at both ends, and the flanges at the ends are used for the installation of the fan, the air inlet duct, and the sealing gasket.

[0043] In this embodiment, the fan motor is a three-phase AC asynchronous motor. The motor can operate under power frequency or variable frequency power supply conditions and is adapted to a three-phase AC power supply voltage of no more than 440V and a frequency of no more than 60Hz.

[0044] The assembly sequence is as follows: first, connect the rotary encoder to the rear end of the motor shaft; then, install the motor on the inner cylinder motor mounting flange plate; next, press-fit the impeller and install the shaft end retaining washer and shaft end nut; then, install the sensor and oil injection line; install the air inlet sealing gasket and air inlet duct; and finally, install the cables of each component and the maintenance window cover.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An axial centrifugal fan, characterized in that, The system includes an air inlet duct (1), a sand baffle ring (3), an outer cylinder (4), an inner cylinder (6), guide vanes (7), a motor (9), and an impeller (15). The inner cylinder (6) is located inside the outer cylinder (4), and multiple guide vanes (7) are spaced circumferentially between them. The motor (9) is located on the inner cylinder (6), and the impeller (15) is mounted on the front end of the motor (9) shaft. The air inlet duct (1) is installed at the air inlet end of the outer cylinder (4), and the small end of the air inlet duct (1) is aligned with the small end of the front disc of the impeller (15), with a gap between them. The sand baffle ring (3) is installed on the inner wall of the outer cylinder (4), and the sand baffle ring (3) is arranged around the large end of the front disc of the impeller, with a gap between them. The outer surface of the sand-blocking ring is 0-2mm higher than the upper contour line of the large end of the impeller front disc; a gap of 2-4mm is left between the sand-blocking ring (3) and the large end of the impeller front disc; Multiple baffles (20) are arranged circumferentially on the inner wall of the outer cylinder (4), and the baffles (20) are located between the sand-blocking ring (3) and the air inlet duct (1); The length direction of the spoiler (20) is parallel to the axial direction of the outer cylinder, and the width of the spoiler (20) is one-tenth of the inner diameter of the outer cylinder; A rotary encoder (10) is provided at the rear end of the motor (9) shaft. The rotary encoder (10) is used to detect the rotation direction and speed of the motor. When the rotation direction of the motor is inconsistent with the preset direction, the rotation direction of the motor is switched by an external control circuit.

2. The axial centrifugal fan according to claim 1, characterized in that, The motor (9) is mounted on the inner cylinder (6) via a motor mounting flange plate (14); an oil injection pipeline (8) is provided to lubricate the motor bearing; a temperature sensor is provided to monitor the temperature of the motor bearing; and a vibration velocity sensor is provided to monitor the vibration velocity value of the motor bearing.

3. The axial centrifugal fan according to claim 2, characterized in that, The outer wall of the outer cylinder (4) is provided with a junction box (12) and a cable outlet window. The junction box (12) is used to install the drive power line of the motor (9). The cable outlet window is used to install the cable connectors of the rotary encoder (10), temperature sensor, and vibration speed sensor. A maintenance window cover (18) is detachably installed on the cable outlet window.

4. The axial centrifugal fan according to claim 1, characterized in that, The impeller and the motor shaft are fitted with a Morse taper hole. The shaft end is provided with a shaft end nut (16) and a retaining washer (17) to prevent the impeller from detaching from the shaft.

5. The axial centrifugal fan according to claim 1, characterized in that, The outer wall of the outer cylinder (4) is provided with a plurality of outer cylinder reinforcing ribs (5) along the circumferential direction; the length of the inner cylinder (6) is less than or equal to half the length of the motor.

6. The axial centrifugal fan according to claim 1, characterized in that, A sealing gasket (2) is provided between the air inlet end of the outer cylinder (4) and the air inlet duct (1).

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