Trapezoidal annular fan for dry-type transformer

Abstract

The invention relates to the technical field of heat dissipation of dry-type transformers, in particular to a trapezoidal annular fan for a dry-type transformer, which comprises a plurality of mounting seats, a closed annular ventilation pipeline is formed by a right ventilation pipeline and a left ventilation pipeline, and then a plurality of annular fans are arranged on the upper side surface of the annular ventilation pipeline. Due to the fact that the fan unit is arranged on one side of the right ventilation pipeline, the flow speed and the air pressure of the ventilation openings closer to the fan unit are relatively large, and at the moment, the flow speed and the air pressure of the ventilation openings are reduced by reducing the port areas of the ventilation openings. Meanwhile, due to the fact that the air flows of the first ventilation opening, the second ventilation opening and the third ventilation opening are the same in unit time, the exhaust air rate of all the ventilation openings is more balanced, and meanwhile the air flows of all the exhaust openings of the annular ventilation pipeline are the same, the air pressure of the annular ventilation pipeline, namely all the exhaust openings is relatively balanced. And the smaller pressure difference is beneficial to shock absorption and noise reduction of the ventilation pipeline of the fan.

Description

Technical Field

[0001] The invention relates to the technical field of fan heat dissipation for dry-type transformers, and in particular to a trapezoidal annular fan for dry-type transformers. Background Art

[0002] Dry-type transformers are different from traditional oil-immersed transformers. They do not require oil as a medium, but use dry insulating materials to achieve insulation and heat dissipation. This design causes the dry-type transformer to generate a certain amount of heat during operation. If this heat cannot be dissipated in a timely and effective manner, it will cause the internal temperature of the transformer to rise, thereby affecting its electrical performance and working stability. Therefore, a good heat dissipation design is essential to ensure the safe and stable operation of the dry-type transformer. In fact, the heat dissipation of dry-type transformers on the market is often cooled by cooling fans. When cooling fans are used for dry-type transformers, the fans are placed on the high and low voltage sides of the lower part of the transformer coil, and the cold air is blown directly into the high and low pressure cooling air ducts of the transformer coil to achieve the purpose of heat dissipation.

[0003] However, since the dry-type transformer has high-voltage and low-voltage sides and is usually composed of three coils connected in series, it is required to bind at least one fan on each side, or bind a fan under each coil on each side. Therefore, a dry-type transformer needs to be equipped with at least two fans. However, the problem of starting multiple fans at the same time has various problems such as insufficient efficiency, high cost, serious energy consumption and high noise.

[0004] Based on this, a trapezoidal ring fan for a dry-type transformer is proposed. Summary of the invention

[0005] The object of the present invention is to provide a trapezoidal annular fan for a dry-type transformer to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a trapezoidal annular fan of a dry-type transformer, comprising a plurality of mounting seats 1, a right ventilation duct 3 is fixedly connected to the upper sides of the plurality of mounting seats 1 on one side, and a left ventilation duct 14 is fixedly connected to the upper sides of the plurality of mounting seats 1 on the other side, the right ventilation duct 3 and the left ventilation duct 14 are both L-shaped in direction, both ends of the right ventilation duct 3 and the left ventilation duct 14 are provided with docking mechanisms, the right ventilation duct 3 and the left ventilation duct 14 are spliced ​​and assembled with each other through the docking mechanisms at both ends to form an annular ventilation duct, and a No. 1 ventilation port 15, a plurality of No. 2 ventilation ports 16 and a No. 3 ventilation port 19 are respectively provided on the upper sides of the annular ventilation duct;

[0007] A centrifugal fan mechanism is disposed on one side of the right ventilation duct 3, an air drainage mechanism is disposed on the upper side of the annular ventilation duct, and a dry-type transformer base 2 is fixedly connected to the lower sides of the plurality of mounting seats 1 .

[0008] As a further solution of the present invention, the docking mechanism includes a sealing plate 18 fixedly connected to one end surface of the left ventilation duct 14 and the right ventilation duct 3, and a sealing groove 17 is opened at the other end surface of the left ventilation duct 14 and the right ventilation duct 3, the sealing groove 17 on the right ventilation duct 3 is plugged into the sealing plate 18 on the left ventilation duct 14, and the sealing plate 18 on the right ventilation duct 3 is plugged into the sealing groove 17 on the left ventilation duct 14.

[0009] As a further solution of the present invention, the cross-sections of the right ventilation duct 3 and the left ventilation duct 14 are both trapezoidal. Compared with square ventilation ducts, trapezoidal ducts exhaust air more evenly.

[0010] As a further solution of the present invention, the port areas of the No. 1 vent 15, the plurality of No. 2 vents 16 and the No. 3 vent 19 are increased in sequence, wherein the No. 1 vent 15 has the smallest area, the No. 3 vent 19 has the largest area, and the areas of the plurality of No. 2 vents 16 are increased in sequence and are between the areas of the No. 1 vent 15 and the No. 3 vent 19;

[0011] The port areas of the No. 1 vent 15, the No. 2 vents 16 and the No. 3 vent 19 increase in sequence from small to large, so that the exhaust volume of each vent is more balanced;

[0012] The ventilation opening areas of the No. 1 ventilation opening 15, the plurality of No. 2 ventilation openings 16 and the No. 3 ventilation opening 19 which increase in order from small to large are used for reducing vibration and noise of the fan.

[0013] As a further solution of the present invention, the centrifugal fan mechanism includes a fan unit 6 connected to one side of the right ventilation duct 3, and the fan unit 6 is a centrifugal fan.

[0014] As a further solution of the present invention, the air drainage mechanism includes a limit platform 8 which is connected to the upper sides of the No. 1 vent 15, the plurality of No. 2 vents 16 and the No. 3 vent 19, each of the limit platforms 8 is provided with a filter slot 12, each of the filter slots 12 is provided with a filter screen 13, and each of the limit platforms 8 is provided with a Venturi shock-absorbing and noise-reducing mechanism on the upper side.

[0015] As a further solution of the present invention, the Venturi shock absorption and noise reduction mechanism includes an air collecting hood 9 connected to the upper side of each of the limit platforms 8, and the upper end of each of the air collecting hoods 9 is connected to a Venturi tube 10, and a sound insulation cover mechanism is provided on one side of the Venturi tube 10.

[0016] As a further solution of the present invention, the sound insulation cover mechanism includes a left sound insulation cover 5 fixedly connected to the upper side of the left ventilation duct 14, a right sound insulation cover 4 is fixedly connected to the upper side of the right ventilation duct 3, and the left sound insulation cover 5 is fixedly connected to the right sound insulation cover 4.

[0017] As a further solution of the present invention, both sides of the left sound insulation cover 5 and the right sound insulation cover 4 include baffles 21, and the multiple Venturi tubes 10 are located between the baffles 21 on both sides. The upper sides of the two baffles 21 are commonly fixedly connected with a cover plate 22, and the cover plate 22 is provided with a plurality of exhaust ports 11, each of the exhaust ports 11 is paired with the upper port of the Venturi tube 10, and a sound-absorbing panel mechanism is lined between the baffles 21 on both sides.

[0018] As a further solution of the present invention, the sound absorbing panel mechanism includes a plurality of pairs of connection frames 20 respectively fixedly connected to the inner sides of the baffles 21 on both sides, and a plurality of sound absorbing panels 7 are arranged between each pair of the connection frames 20 .

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention forms a closed annular ventilation duct through the right ventilation duct 3 and the left ventilation duct 14, and then arranges a No. 1 ventilation port 15, a plurality of No. 2 ventilation ports 16 and a No. 3 ventilation port 19 with increasing areas from small to large on the upper side of the annular ventilation duct. Since the fan unit 6 is arranged on one side of the right ventilation duct 3, the flow velocity and wind pressure of the ventilation ports closer to the fan unit 6 are relatively large. At this time, by reducing the port area of ​​the ventilation ports, the air flow rate per unit time of each No. 1 ventilation port 15, No. 2 ventilation port 16 and No. 3 ventilation port 19 can be kept equal, so that the exhaust volume of each ventilation port is more balanced. At the same time, since the air flow rate at each exhaust port on the annular ventilation duct is the same, the air pressure at each exhaust port of the annular ventilation duct is relatively balanced, and the smaller pressure difference is conducive to the vibration reduction and noise reduction of the fan ventilation duct;

[0021] 2. The present invention forms a closed annular ventilation duct through the right ventilation duct 3 and the left ventilation duct 14. It only needs to place an annular ventilation duct under the dry-type transformer coil to simultaneously supply air and dissipate heat to the high and low voltage sides of multiple coils of the dry-type transformer. Different from the design mode of setting multiple or one cooling fan on both sides of the high and low voltage coils of the traditional dry-type transformer, the present invention can significantly reduce the number of fans, improve the utilization rate of the fans, reduce the energy consumption of the fans, and avoid the problem of excessive noise caused by the simultaneous operation of multiple fans;

[0022] 3. The present invention provides a venturi tube 10 at each of the No. 1 vent 15, the No. 2 vents 16 and the No. 3 vent 19. The working principle of the venturi tube 10 is based on the Bernoulli principle, that is, when a fluid flows through a gradually narrowing channel, the flow rate will increase and the pressure will decrease. This change in speed and pressure causes a specific dynamic effect when the fluid flows in the venturi tube. Through the carefully designed venturi tube structure, the turbulence and vibration of the airflow in the pipeline can be effectively reduced, thereby reducing the generation of noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a front view of the present invention;

[0024] Figure 2 It is a schematic diagram of a first explosion structure of the present invention;

[0025] Figure 3 It is a schematic diagram of a second explosion structure of the present invention;

[0026] Figure 4 It is a schematic diagram of a third explosion structure of the present invention;

[0027] Figure 5 It is a schematic diagram of the local structure of the present invention;

[0028] Figure 6 for Figure 5 Schematic diagram of the explosion structure;

[0029] Figure 7 It is a structural schematic diagram of the air drainage mechanism in the present invention.

[0030] In the figure: 1. Mounting base; 2. Dry-type transformer base; 3. Right ventilation duct; 4. Right soundproof cover; 5. Left soundproof cover; 6. Fan unit; 7. Sound-absorbing board; 8. Limiting table; 9. Wind collecting cover; 10. Venturi tube; 11. Exhaust port; 12. Filter slot; 13. Filter screen; 14. Left ventilation duct; 15. Ventilation port No. 1; 16. Ventilation port No. 2; 17. Sealing slot; 18. Sealing plate; 19. Ventilation port No. 3; 20. Connection frame; 21. Baffle; 22. Cover plate. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] See also Figures 1 to 7The present invention provides a technical solution: a trapezoidal annular fan of a trapezoidal dry-type transformer, comprising four mounting seats 1, the upper sides of the four mounting seats 1 on one side are commonly fixedly connected with a right ventilation duct 3, and the upper sides of the multiple mounting seats 1 on the other side are commonly fixedly connected with a left ventilation duct 14, the pipeline directions of the right ventilation duct 3 and the left ventilation duct 14 are both L-shaped structures, both ends of the right ventilation duct 3 and the left ventilation duct 14 are provided with docking member mechanisms, the right ventilation duct 3 and the left ventilation duct 14 are spliced ​​and assembled with each other through the docking member mechanisms at both ends to form an annular ventilation duct, and the upper side of the annular ventilation duct is respectively provided with a No. 1 ventilation port 15, three No. 2 ventilation ports 16 and a No. 3 ventilation port 19;

[0033] By means of two L-shaped structures that can be docked with each other, the annular area below the dry-type transformer coil is spliced ​​to reduce the space occupied by the fan. It should be noted that the height of the right ventilation duct 3 and the left ventilation duct 14, as well as the height value setting of the right sound insulation cover 4 and the left sound insulation cover 5, need to comprehensively consider the spatial distance between the dry-type transformer coil and the dry-type transformer base 2, which is sufficient to accommodate the height of the sound insulation cover and the ventilation duct. By splicing the right ventilation duct 3 and the left ventilation duct 14 into a rectangular, U-shaped annular duct, it is suitable for the purpose of all-around air cooling of the dry-type transformer, which can significantly improve the utilization efficiency of a single fan. Compared with the traditional dry-type transformer heat dissipation method, it can significantly reduce the number of fans purchased and reduce costs.

[0034] Please combine Figure 1 and Figure 2 As shown, a centrifugal fan mechanism is provided on one side of the right ventilation duct 3, an air drainage mechanism is provided on the upper side of the annular ventilation duct, and a dry-type transformer base 2 is fixedly connected to the lower sides of the four mounting seats 1. The mounting seats 1 in this embodiment can add shock-absorbing structures such as rubber pads to further reduce the vibration generated when the fan is working, which is not only beneficial to prolonging the life of the fan, but also helps to reduce noise. The mounting seat 1 is connected to the dry-type transformer base through a threaded positioning connection.

[0035] Please combine Figure 4 As shown, the docking mechanism includes a sealing plate 18 fixedly connected at one end surface of the left ventilation duct 14 and the right ventilation duct 3, and a sealing groove 17 is opened at the other end surface of the left ventilation duct 14 and the right ventilation duct 3. The sealing groove 17 on the right ventilation duct 3 is plugged into the sealing plate 18 on the left ventilation duct 14, and the sealing plate 18 on the right ventilation duct 3 is plugged into the sealing groove 17 on the left ventilation duct 14. Fixing nuts are arranged on the outer sides of the two sealing grooves 17. In an actual installation scenario, a sealing tape or sealant is placed between the sealing groove 17 and the sealing plate 18 to improve the sealing performance of the entire annular ventilation duct.

[0036] Please combine Figure 4As shown, the pipe cross-sections of the right ventilation duct 3 and the left ventilation duct 14 are both trapezoidal. Compared with the square ventilation duct, the trapezoidal duct has more uniform exhaust. After a large number of modeling and statistical analysis of the right ventilation duct 3 and the left ventilation duct 14 with different trapezoidal port surfaces, trapezoidal ventilation ducts of various sizes and angles including isosceles trapezoids are analyzed, and the best trapezoidal ventilation duct port trapezoidal geometry values ​​and data with the most uniform exhaust suitable for a specific type of dry-type transformer are obtained as the right ventilation duct 3 and the left ventilation duct 14 port type of the specific type of dry-type transformer.

[0037] Please combine Figure 4 As shown, the port areas of vent No. 1 15, three vent No. 2 16 and vent No. 3 19 increase successively, among which vent No. 1 15 has the smallest area, vent No. 3 19 has the largest area, and the areas of the three vent No. 2 16 increase successively and are between the areas of vent No. 1 15 and vent No. 3 19. The port areas of vent No. 1 15, three vent No. 2 16 and vent No. 3 19 increase successively from small to large so that the exhaust volume of each vent is more balanced, and the vent areas of vent No. 1 15, three vent No. 2 16 and vent No. 3 19 increase successively from small to large are used for fan vibration reduction and noise reduction.

[0038] In the present embodiment, the number of exhaust vents arranged in the L-shaped long-distance sections of the left ventilation duct 14 and the right ventilation duct 3 is 3, and each No. 2 vent 16 corresponds to a coil in the dry-type transformer. Generally, there are 3 coils in the dry-type transformer, and a one-to-one pairing is achieved, which helps to provide a heat dissipation effect for the coils. It is particularly important to note that the area sizes of the No. 1 vent 15, the three No. 2 vents 16 and the No. 3 vent 19 need to meet the requirement that, in the case of a single-sided fan, although the air flow velocities of each vent are different, the gas flow rate passing through the vent per unit time must be the same, so as to ensure the air pressure balance of the entire annular ventilation duct.

[0039] Please combine Figure 1 As shown, the centrifugal fan mechanism includes a fan unit 6 connected to one side of the right ventilation duct 3. The fan unit 6 is a centrifugal fan. It should be noted that the centrifugal fan of the fan unit 6 in this embodiment is a vortex centrifugal fan with a flow rate of (800-1300) m 3 / h, the power is 240W-720W.

[0040] Please combine Figure 2As shown, the air diversion mechanism includes a limit platform 8 which is connected to the upper sides of the No. 1 vent 15, the three No. 2 vents 16 and the No. 3 vent 19. The limit platform 8 is fixedly connected to the annular ventilation duct through a nut, and its upper side and lower side are opened. A filter slot 12 is provided on each limit platform 8, and a filter screen 13 is provided inside each filter slot 12. The filter screen 13 and the filter slot 12 are of detachable design, and a Venturi shock-absorbing and noise-reducing mechanism is provided on the upper side of each limit platform 8.

[0041] Please combine Figure 7 As shown, the Venturi vibration reduction and noise reduction mechanism includes an air collecting hood 9 connected to the upper side of each limit platform 8, the upper end of each air collecting hood 9 is connected to a Venturi tube 10, and a sound insulation cover mechanism is provided on one side of the Venturi tube 10.

[0042] It should be noted that the design of the diameter of the pipes at both ends of the Venturi tube 10 needs to be combined with the actual heat dissipation requirements of the dry-type transformer. Generally, the thinner the diameter of the end of the Venturi tube 10, the greater the wind flow rate, and the better the effect of flushing the dry-type transformer coil. However, it affects the exhaust flow rate of the Venturi tube 10 with a smaller diameter.

[0043] Please combine Figure 3 As shown, the sound insulation cover mechanism includes a left sound insulation cover 5 fixedly connected to the upper side of the left ventilation duct 14, a right sound insulation cover 4 fixedly connected to the upper side of the right ventilation duct 3, the left sound insulation cover 5 and the right sound insulation cover 4 are fixedly connected, and the inner walls of the left sound insulation cover 5 and the right sound insulation cover 4 are provided with sound absorbing structures, such as sound absorbing panels with honeycomb openings.

[0044] Please combine Figure 3 As shown, both sides of the left soundproof cover 5 and the right soundproof cover 4 include baffles 21, and eight venturi tubes 10 are located between the baffles 21 on both sides. The upper sides of the two baffles 21 are fixedly connected with a cover plate 22, and the cover plate 22 is provided with four exhaust ports 11, each exhaust port 11 is paired with the upper end of the venturi tube 10, and a sound-absorbing panel mechanism is lined between the baffles 21 on both sides.

[0045] Please combine Figure 3 As shown, the sound absorbing panel mechanism includes a plurality of pairs of connection frames 20 respectively fixedly connected to the inner sides of the baffles 21 on both sides, a plurality of sound absorbing panels 7 are arranged between each pair of connection frames 20, and the sound absorbing panels 7 and the connection frames 20 are in a detachable snap-connected relationship.

[0046] Working principle: When the staff needs to install the trapezoidal annular fan of the present invention on a dry-type transformer that has not been installed with a fan, first, the two L-shaped right ventilation ducts 3 and left ventilation ducts 14 are bypassed from both sides below the dry-type transformer coil, so that the sealing plates 18 at both ends are inserted into the sealing grooves 17 and connected to each other, the right sound insulation cover 4 and the left sound insulation cover 5 are respectively installed on the upper side of the right ventilation duct 3 and the left ventilation duct 14, and are connected to each other through the mortise and tenon process, and the ventilation duct is fixedly connected to the base of the dry-type transformer through the mounting seat 1 from the lower side of the right ventilation duct 3 and the left ventilation duct 14, and the fan unit 6 is started, and the air flows along the right ventilation duct 3 and The annular ventilation duct formed by the left ventilation duct 14 blows air to both sides, and the blown air first flows out from the No. 1 ventilation port 15 which is closest to the fan unit 6, and then flows out from multiple No. 2 ventilation ports 16 in sequence along the right ventilation duct 3 and the left ventilation duct 14 on both sides of the annular ventilation duct until it flows out from the No. 3 ventilation port 19 which has the largest ventilation port area. Since the exhaust port areas of the No. 1 ventilation port 15, multiple No. 2 ventilation ports 16 and No. 3 ventilation port 19 gradually increase from small to large, relatively speaking, the closer the No. 1 ventilation port 15 is to the fan unit 6, the greater the flow rate is, and since the port area is small, each No. 1 ventilation port 15, No. 2 ventilation ports 16, No. 3 ventilation ports 19 can achieve a good ventilation effect. The volume of air discharged per unit time from the multiple No. 2 vents 16 and the No. 3 vents 19, that is, the flow rate, is the same, so that the air flow rate entering the coil from the bottom to the top of the entire annular area under the entire dry-type transformer coil is balanced, and the dry-type transformer coil can be fully cooled. At the same time, since the flow rates of the No. 1 vents 15, the multiple No. 2 vents 16 and the No. 3 vents 19 in the annular ventilation duct are the same, the internal pressure of the entire annular ventilation duct is relatively balanced, thereby achieving the effect of reducing vibration and reducing noise. After the air passes upward through the No. 1 vents 15, the multiple No. 2 vents 16 and the No. 3 vents 19, it passes through the limiting The filter screen 13 in the filter slot 12 on the platform 8 can purify and filter the air to prevent dust from accumulating inside the transformer collar. When the air continues to flow upward, the air directly enters the venturi tube 10 through the wind collecting hood 9. The Venturi phenomenon produced by the unique structure of the venturi tube 10 can effectively reduce the turbulence and vibration of the airflow in the pipeline, thereby reducing the generation of noise. In addition, a right soundproof cover 4 and a left soundproof cover 5 are arranged above the annular ventilation duct, and the right soundproof cover 4 and the left soundproof cover 5 are lined with multi-layer sound-absorbing panels 7 to further absorb and digest the noise generated by the fan, thereby achieving the overall noise reduction effect of the present invention.

[0047] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A trapezoidal annular fan for a dry-type transformer, comprising a plurality of mounting seats (1), characterized in that: A right ventilation duct (3) is fixedly connected to the upper sides of the plurality of mounting seats (1) located on one side, and a left ventilation duct (14) is fixedly connected to the upper sides of the plurality of mounting seats (1) located on the other side. The pipe directions of the right ventilation duct (3) and the left ventilation duct (14) are both L-shaped structures. Both ends of the right ventilation duct (3) and the left ventilation duct (14) are provided with docking member mechanisms. The right ventilation duct (3) and the left ventilation duct (14) are spliced ​​and assembled with each other through the docking member mechanisms at both ends to form an annular ventilation duct. A No. 1 ventilation port (15), a plurality of No. 2 ventilation ports (16) and a No. 3 ventilation port (19) are respectively provided on the upper side of the annular ventilation duct. A centrifugal fan mechanism is provided on one side of the right ventilation duct (3), an air drainage mechanism is provided on the upper side of the annular ventilation duct, and a dry-type transformer base (2) is fixedly connected to the lower sides of the plurality of mounting seats (1).

2. The trapezoidal annular fan for a dry-type transformer according to claim 1, characterized in that: The docking mechanism comprises a sealing plate (18) fixedly connected to one end surface of the left ventilation duct (14) and the right ventilation duct (3); a sealing groove (17) is provided at the other end surface of the left ventilation duct (14) and the right ventilation duct (3); the sealing groove (17) on the right ventilation duct (3) is plugged into the sealing plate (18) on the left ventilation duct (14); and the sealing plate (18) on the right ventilation duct (3) is plugged into the sealing groove (17) on the left ventilation duct (14).

3. The trapezoidal annular fan for a dry-type transformer according to claim 1, characterized in that: The cross-sections of the right ventilation duct (3) and the left ventilation duct (14) are both trapezoidal. Compared with square ventilation ducts, trapezoidal ducts exhaust air more evenly.

4. The trapezoidal annular fan for a dry-type transformer according to claim 1, characterized in that: The port areas of the No. 1 vent (15), the plurality of No. 2 vents (16) and the No. 3 vent (19) increase in sequence, wherein the No. 1 vent (15) has the smallest area, the No. 3 vent (19) has the largest area, and the areas of the plurality of No. 2 vents (16) increase in sequence and are between the areas of the No. 1 vent (15) and the No. 3 vent (19); The port areas of the No. 1 vent (15), the plurality of No. 2 vents (16) and the No. 3 vent (19) increase in sequence from small to large, so that the exhaust volume of each vent is more balanced; The ventilation opening areas of the No. 1 ventilation opening (15), the plurality of No. 2 ventilation openings (16) and the No. 3 ventilation opening (19) which increase in order from small to large are used for reducing vibration and noise of the fan.

5. The trapezoidal annular fan for a dry-type transformer according to claim 1, characterized in that: The centrifugal fan mechanism comprises a fan unit (6) connected to one side of the right ventilation duct (3); the fan unit (6) is a centrifugal fan.

6. The trapezoidal annular fan for a dry-type transformer according to claim 1, characterized in that: The air drainage mechanism comprises a limiting platform (8) which is connected to the upper sides of the No. 1 ventilation port (15), the plurality of No. 2 ventilation ports (16) and the No. 3 ventilation port (19); each of the limiting platforms (8) is provided with a filter slot (12); each of the filter slots (12) is provided with a filter screen (13); and each of the limiting platforms (8) is provided with a Venturi shock-absorbing and noise-reducing mechanism on the upper side.

7. The trapezoidal annular fan for a dry-type transformer according to claim 6, characterized in that: The Venturi vibration reduction and noise reduction mechanism comprises an air collecting hood (9) connected to the upper side of each of the limit platforms (8), the upper end of each of the air collecting hoods (9) is connected to a Venturi tube (10), and a soundproof hood mechanism is provided on one side of the Venturi tube (10).

8. The trapezoidal annular fan for a dry-type transformer according to claim 7, characterized in that: The soundproof cover mechanism comprises a left soundproof cover (5) fixedly connected to the upper side of the left ventilation duct (14), a right soundproof cover (4) fixedly connected to the upper side of the right ventilation duct (3), and the left soundproof cover (5) is fixedly connected to the right soundproof cover (4).

9. The trapezoidal annular fan for a dry-type transformer according to claim 8, characterized in that: Both sides of the left soundproof cover (5) and the right soundproof cover (4) include baffles (21), a plurality of the Venturi tubes (10) are located between the baffles (21) on both sides, a cover plate (22) is fixedly connected to the upper sides of the two baffles (21), a plurality of exhaust ports (11) are provided on the cover plate (22), each exhaust port (11) is paired with an upper port of the Venturi tube (10), and a sound absorbing panel mechanism is lined between the baffles (21) on both sides.

10. The trapezoidal annular fan for a dry-type transformer according to claim 9, characterized in that: The sound absorbing panel mechanism comprises a plurality of pairs of connection frames (20) respectively fixedly connected to the inner sides of the baffles (21) on both sides, and a plurality of sound absorbing panels (7) are arranged between each pair of the connection frames (20).

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