Motor external type totally-enclosed zero-leakage centrifugal fan driven by magnetic coupling

Abstract

The invention relates to the technical field of centrifugal fans, in particular to a fully-closed zero-leakage centrifugal fan with an external motor driven by magnetic coupling, which comprises a mounting support, an anti-leakage structure and a driving motor are bolted to the top of the mounting support, and a fan body is bolted to the front side of the anti-leakage structure. The impeller shaft end of the fan body is in bolted connection with a connecting shaft, the right end of the connecting shaft and the output end of the driving motor are both provided with magnetic couplers, the surface of the connecting shaft is sleeved with a bearing seat, and the bottom of the bearing seat is in bolted connection with a leakage-proof structure; the anti-leakage structure comprises a closed cover shell, a partition plate is connected to the left side of the interior of the closed cover shell in a bolted mode, and the two sides of the interior of the closed cover shell are divided into a buffering cavity and a protection cavity through the partition plate. The fully-closed zero-leakage centrifugal fan with the externally-arranged motor is driven by magnetic coupling, and has the advantages that fully-closed zero leakage can be achieved, and the motor can be thoroughly isolated from harmful media.

Description

Technical Field

[0001] This invention relates to the field of centrifugal fan technology, specifically to a fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling. Background Technology

[0002] As is well known, in industries such as chemical, cable, and environmental protection, it is often necessary to transport media containing corrosive, toxic and harmful gases such as hydrogen sulfide. Traditional centrifugal fans mostly adopt a structure in which the motor and impeller are directly connected, and the seal is achieved through shaft seal. In the existing technology, fans used in such scenarios mostly adopt a structure in which the motor is completely enclosed and the shaft seal is used, that is, the motor is enclosed in a cylinder and the shaft seal is used to prevent the media from leaking.

[0003] Existing technologies include structures that completely enclose the motor within a cylinder. However, since the motor and the medium are in the same enclosed space, harmful media can leak from the fan casing into the cylinder when the shaft seal fails. Although it will no longer leak into the atmosphere, the leaked corrosive media will still corrode the motor windings, bearings, and other components, leading to frequent motor failures and extremely high maintenance costs. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling. This fan has the advantages of achieving full enclosure and zero leakage, and completely isolating the motor from harmful media.

[0005] (II) Technical Solution The above-mentioned technical objective of the present invention is achieved through the following technical solution: a fully enclosed zero-leakage centrifugal fan with an external motor driven by magnetic coupling, including a mounting support, a leak-proof structure and a drive motor are bolted to the top of the mounting support, and a fan body is bolted to the front side of the leak-proof structure, and a connecting shaft is bolted to the impeller shaft end of the fan body, and magnetic couplers are provided at the right end of the connecting shaft and the output end of the drive motor, a bearing seat is sleeved on the surface of the connecting shaft, and the bottom of the bearing seat is bolted to the leak-proof structure; The leak-proof structure includes a closed cover, with a partition plate bolted to the left side inside the closed cover. The partition plate divides the two sides inside the closed cover into a buffer chamber and a protective chamber. A leak discharge mechanism is installed inside the buffer chamber, and the output end of the leak discharge mechanism is fixedly connected to a negative pressure circuit. The other end of the negative pressure circuit is fixedly connected to the air outlet pipe of the fan body. The leak discharge mechanism works in conjunction with the partition plate.

[0006] By adopting the above technical solution and setting up an anti-leakage structure, on the one hand, the first shaft seal serves as the first layer of sealing, and the enclosed casing provides a second layer of sealing protection. Even if the first shaft seal is damaged, the gas will not diffuse into the atmosphere within the buffer chamber. The leakage discharge mechanism, triggered by pressure, automatically opens the negative pressure circuit when the medium leaks, returning the leaked medium to the fan body to prevent accumulation and corrosion. At the same time, the magnetic coupling drives the fan shaft to rotate, isolating the motor from external corrosion, thus preventing motor failure. The entire fan fully meets the requirements of zero leakage and long-term normal operation. On the other hand, when the first shaft seal is damaged and leaks, the leakage discharge mechanism automatically opens the partition plate, allowing the cooling nitrogen in the protective chamber to automatically replenish the buffer chamber, quickly pushing the medium from the buffer chamber into the fan body, accelerating the discharge of the medium. This creates a safe and clean local environment for maintenance, greatly improving the operation and maintenance response speed and personnel safety, and reducing unplanned downtime and high maintenance costs caused by corrosive medium leaks.

[0007] The present invention is further configured such that: a first shaft seal is provided at the connection between the impeller shaft end of the fan body and the closed cover, and a second shaft seal is provided at the connection between the connecting shaft and the partition plate.

[0008] By adopting the above technical solution, the basic sealing performance is enhanced through the structural design of the first shaft seal and the second shaft seal. The first shaft seal targets the core sealing surface between the fan body and the enclosed casing, while the second shaft seal targets the isolation surface between the buffer chamber and the protective chamber. This dual protection significantly reduces the risk of leakage.

[0009] The invention is further configured such that: the leakage discharge mechanism includes a fixed cylinder, the left side of which is fixedly connected to a negative pressure circuit via a pipeline; a movable seat is slidably disposed inside the fixed cylinder, and a connecting rod is welded to the bottom of the movable seat; a sealing seat is welded to the bottom of the connecting rod, and the surface of the sealing seat is in close contact with the inner wall of the fixed cylinder; a fixed seat is threadedly disposed at the top inside the fixed cylinder, and a pressure seat is slidably disposed at the bottom of the fixed seat; a return spring is disposed inside the movable seat, and the other end of the return spring abuts against the pressure seat; a disconnection component is disposed on the left side inside the fixed seat, and the disconnection component is electrically connected to the controller of the drive motor.

[0010] By adopting the above technical solution and setting up a leakage discharge mechanism, the pressure in the buffer chamber is stable during normal operation. The moving seat is in a closed position under the action of the return spring, and the sealing seat seals the lower end of the fixed cylinder. When the first shaft seal fails and harmful gas leaks into the buffer chamber, causing its pressure to rise, the air pressure pushes the moving seat to move upward against the force of the return spring. The upward movement of the moving seat first cuts off the power supply to the drive motor through the disconnect component, realizing automatic shutdown. Then, the sealing seat leaves the opening at the lower end of the fixed cylinder, making the buffer chamber connected to the negative pressure circuit. The leaked gas is drawn in and discharged back to the process system under the negative pressure of the blower body's outlet pipe. This can directly convert the physical signal of leakage (pressure rise) into two consecutive protective actions. On the one hand, it can make the blower body stop immediately to prevent the continuous operation under fault conditions from causing greater damage. On the other hand, it can automatically open the discharge path to actively guide the leaked medium and avoid the infinite accumulation of pressure in the buffer chamber.

[0011] The present invention is further configured such that: the disconnecting component includes a movable column, the movable column is slidably disposed inside the fixed base, and the bottom of the movable column is fixedly connected to the movable base; a connecting terminal is threadedly connected to the left side inside the fixed base, and a stationary contact is welded to the bottom of the connecting terminal; a movable contact is welded to the top of the movable column, and the movable contact is used in conjunction with the stationary contact.

[0012] By adopting the above technical solution, and by setting a disconnect component, when the pressure in the buffer chamber pushes the moving seat upward, the moving column fixed to it rises and falls accordingly. The moving contact at the top of the moving column contacts the stationary contact connected to the fixed seat, thereby cutting off the control circuit and stopping the operation of the fan body by the drive motor, which makes it easier for staff to deal with the leakage in a timely manner.

[0013] The invention is further configured such that: the top of the pressure seat is rotatably contacted by an adjusting screw, and the adjusting screw is threadedly connected inside the fixed seat.

[0014] By adopting the above technical solution, the trigger pressure of the leakage discharge mechanism can be flexibly adjusted by adjusting the setting of the screw, which can be adapted to application scenarios with different media pressures and different leakage risk levels, thus greatly improving the versatility of the device.

[0015] The invention is further configured such that: the partition plate includes a pressure-bearing partition plate; a movable plate is slidably disposed on the left side inside the pressure-bearing partition plate; both the movable plate and the pressure-bearing partition plate have several air holes inside; a connecting frame is rotatably connected to the top of the movable plate; a connecting rod is rotatably connected to the other end inside the connecting frame; the connecting rod is slidably disposed inside the fixed seat; a fixed frame is rotatably sleeved on the surface of the connecting frame; the top of the fixed frame is bolted to the inner wall of the closed cover; a fixed column is welded to the bottom of the movable plate; a fixed sleeve is disposed at the bottom of the fixed column; and the bottom of the fixed sleeve is bolted to the pressure-bearing partition plate; a retaining ring and a blocking block are welded to the inner wall of the fixed sleeve and the surface of the fixed column, respectively; the retaining ring and the blocking block are used in conjunction.

[0016] Using the above technical solution, by setting a partition plate, under normal conditions, the movable plate is located in the upper part inside the pressure-bearing partition plate, and the vents on it are arranged alternately with the vents on the pressure-bearing partition plate, essentially blocking the gas passage between the two chambers. When the leakage discharge mechanism is activated and the moving seat moves upward, the movable plate is driven to slide downward in the guide groove through the linkage mechanism composed of the connecting rod and the connecting frame. After the movable plate descends to a certain position, its vents gradually align with the vents on the pressure-bearing partition plate, forming a connecting channel. At the same time, the fixing post at the bottom of the movable plate is inserted into the fixing sleeve, and the retaining ring on the surface of the fixing post engages with the retaining ring inside the fixing sleeve. The partitions form an interlocking structure to prevent accidental movement of the movable plate from affecting the connection of the vents. At this time, the positive pressure nitrogen gas maintained in the protective chamber (replenished by a small gas tank and maintained by the shutdown of the circulating heat dissipation system) can flow into the buffer chamber through the aligned vents to flush and replace the residual harmful gas from the leak. It can quickly push the harmful gas into the fan body casing, which is convenient for subsequent maintenance and treatment of the leak. After maintenance is completed, the movable seat is reset under the elastic action of the reset spring, and the movable plate is driven to move up and reset through the linkage mechanism. The vents are misaligned and closed again, restoring the isolation state of the two chambers.

[0017] The present invention is further configured such that: a guide groove is provided on the left side of the pressure-bearing partition, the movable plate is slidably disposed inside the guide groove, and the fixed sleeve is located at the bottom of the guide groove; the movable plate and the air holes on the pressure-bearing partition are staggered and evenly distributed along the vertical direction.

[0018] By adopting the above technical solution, the guide groove of the pressure-bearing baffle provides sliding guidance for the movable plate, ensuring that the movable plate moves smoothly and avoiding misalignment that would cause the air holes to not be accurately aligned. The air holes on the movable plate and the pressure-bearing baffle are staggered, which completely blocks the buffer chamber and the protective chamber under normal conditions. When leakage occurs, the movable plate slides to the position where the air holes are aligned, forming a connecting channel. The air holes are evenly distributed in the vertical direction, ensuring that the pressure in the chamber is uniform and balanced and the medium flows smoothly.

[0019] The present invention is further configured such that: both the fixing sleeve and the blocking block are made of elastic material, the interior of the fixing sleeve has a number of expansion notches in a ring shape, and the top of the fixing sleeve has a guide bevel.

[0020] By adopting the above technical solution, the fixing sleeve is made of elastic material and has an expansion notch, so that its inner diameter has a certain elastic deformation capacity. When the fixing column is inserted, the guide bevel guides it in, and the elastic inner wall provides friction constraint. Thus, the position of the movable plate can be locked by the cooperation of the retaining ring and the blocking block, preventing the moving seat from affecting the position of the movable plate under pressure fluctuations, thereby ensuring the connectivity between the air holes.

[0021] The invention is further configured such that: the leak-proof structure also includes a circulating heat dissipation mechanism, the circulating heat dissipation mechanism includes an outer cooling jacket and an inner cooling jacket, the outer cooling jacket and the inner cooling jacket are coaxially sleeved on the surface of the magnetic coupler inside the closed shell, a cooling channel is formed between the outer cooling jacket and the inner cooling jacket, and a guide ring is welded to the left side of both the outer cooling jacket and the inner cooling jacket, a sealing plate is welded between the left sides of the two guide rings, and the sealing plate has a plurality of spray holes arranged in a ring shape inside, a spiral flow guiding protrusion is welded to the inner wall of the outer cooling jacket, and heat dissipation fins are welded to the static shell surface of the magnetic coupler inside the closed shell, and the heat dissipation fins are used in conjunction with the inner cooling jacket.

[0022] By adopting the above technical solution, a circulating heat dissipation mechanism is set up. The outer and inner cooling jackets are coaxially sleeved on the surface of the magnetic coupler, forming a closed cooling channel between them. The threaded guide protrusions on the inner wall of the outer cooling jacket cause the low-temperature nitrogen to form a spiral flow in the channel, prolonging the heat exchange time. The heat dissipation fins on the surface of the magnetic coupler increase the heat dissipation area and fit tightly with the inner cooling jacket, efficiently transferring heat to the low-temperature nitrogen. Furthermore, the guide ring cooperates with the sealing plate, allowing the low-temperature nitrogen to be sprayed onto the bearing housing through the injection holes of the sealing plate, achieving the effect of heat dissipation for the bearing housing. After absorbing heat in the channel, the low-temperature nitrogen flows through the shell-and-tube heat exchanger to achieve cooling, and then flows back to the protective cavity through the circulating pump, forming a closed-loop heat dissipation. This can dissipate the heat generated by the high-speed operation of the magnetic coupler and the bearing housing, ensuring the long-term stable operation of the magnetic coupler and the bearing housing.

[0023] The invention is further configured such that: a shell-and-tube heat exchanger is bolted to the top of the enclosed casing; a circulating pump is fixedly connected to the left side of the shell-and-tube heat exchanger via a pipeline, and the input end of the circulating pump is connected to the protective cavity; the shell-and-tube heat exchanger is fixedly connected to the outer cooling jacket via a pipeline; a small gas storage tank connected to the top of the enclosed casing is bolted to the top of the enclosed casing, and an electrically controlled valve is provided at the connection between the small gas storage tank and the enclosed casing.

[0024] Using the above technical solution, the nitrogen gas whose temperature rises in the protective cavity is extracted by a circulating pump and transported to a shell-and-tube heat exchanger. In the heat exchanger, the nitrogen gas exchanges heat with the cooling water (or air) on the shell side, and its temperature decreases. The cooled nitrogen gas is then pumped back into the inlet of the circulating heat dissipation mechanism to start a new cycle. The small gas storage tank serves as a pressure buffer and supplementary gas source, providing additional gas supply during the harmful gas purification stage.

[0025] (III) Beneficial Effects Compared with the prior art, the present invention provides a fully enclosed zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling, which has the following advantages: This fully enclosed, zero-leakage centrifugal fan, driven by a magnetically coupled external motor, employs a leak-proof structure. Firstly, a first shaft seal provides the initial seal, while the enclosed casing provides a second. Even if the first shaft seal fails, the gas remains within the buffer chamber and does not diffuse into the atmosphere. The leakage discharge mechanism, triggered by pressure, automatically opens a negative pressure circuit in the event of a leak, returning the leaked medium to the fan body to prevent corrosion. Simultaneously, the magnetic coupling drives the fan shaft, isolating the motor and preventing corrosion-related malfunctions. The entire fan fully meets the requirements for zero leakage and long-term normal operation. Secondly, in the event of a leak due to a failed first shaft seal, the leakage discharge mechanism automatically opens a partition plate, allowing dissipating nitrogen from the protective chamber to automatically replenish the buffer chamber. This rapidly pushes the medium from the buffer chamber into the fan body, accelerating discharge and creating a safe and clean local environment for maintenance. This significantly improves operational response speed and personnel safety, while reducing unplanned downtime and high maintenance costs caused by corrosive media leaks. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram showing the connection between the fan body, the enclosed casing, the magnetic coupler, and the drive motor in this invention. Figure 3 This is a schematic diagram showing the connection between the leak-proof structure and the fan body in this invention; Figure 4 This is a schematic diagram of the leakage discharge mechanism in this invention; Figure 5 This is a schematic diagram of the partition plate in this invention; Figure 6 This is a schematic diagram showing the connection between the movable plate and the pressure-bearing partition in this invention; Figure 7 This is a schematic diagram showing the connection between the fixed base and the disconnection component in this invention; Figure 8 This is a schematic diagram of the circulating heat dissipation mechanism in this invention; Figure 9 This is a schematic diagram showing the connection between the circulating heat dissipation mechanism and the shell-and-tube heat exchanger in this invention.

[0027] In the diagram: 1. Mounting support; 2. Leak-proof structure; 21. Enclosed casing; 22. Partition plate; 221. Pressure-bearing partition plate; 222. Movable plate; 223. Vent; 224. Connecting frame; 225. Connecting rod; 226. Fixing frame; 227. Fixing column; 228. Fixing sleeve; 229. Snap ring; 2210. Barrier block; 23. Buffer chamber; 24. Protective chamber; 25. Leakage discharge mechanism; 251. Fixed cylinder; 252. Moving seat; 253. Connecting rod; 254. Sealing seat; 255. Fixed seat; 256. Pressure seat; 257. Return spring; 258. Disconnection assembly ; 258a, Moving column; 258b, Connecting terminal; 258c, Moving contact; 258d, Stationary contact; 26, Negative pressure circuit; 3, Drive motor; 4, Fan body; 5, Connecting shaft; 6, Magnetic coupler; 7, Bearing housing; 8, Circulating heat dissipation mechanism; 81, Outer cooling jacket; 82, Inner cooling jacket; 83, Cooling channel; 84, Guide ring; 85, Sealing plate; 86, Injection hole; 87, Spiral guide protrusion; 88, Heat dissipation fins; 9, First shaft seal; 10, Second shaft seal; 11, Adjusting screw; 12, Shell and tube heat exchanger; 13, Circulating pump; 14, Small air storage tank. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] Please see Figure 1-7 A fully enclosed zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling includes a mounting support 1. A leak-proof structure 2 and a drive motor 3 are bolted to the top of the mounting support 1. A fan body 4 is bolted to the front side of the leak-proof structure 2. A connecting shaft 5 is bolted to the impeller shaft end of the fan body 4. A magnetic coupler 6 is provided at the right end of the connecting shaft 5 and the output end of the drive motor 3. A bearing seat 7 is sleeved on the surface of the connecting shaft 5. The bottom of the bearing seat 7 is bolted to the leak-proof structure 2. The leak-proof structure 2 includes a closed housing 21. A partition plate 22 is bolted to the left side inside the closed housing 21, dividing the inside of the closed housing 21 into a buffer chamber 23 and a protective chamber 24. A leak discharge mechanism 25 is installed inside the buffer chamber 23, and the output end of the leak discharge mechanism 25 is fixedly connected to a negative pressure circuit 26. The other end of the negative pressure circuit 26 is fixedly connected to the air outlet pipe of the fan body 4. The leak discharge mechanism 25 works in conjunction with the partition plate 22. By setting up the leak-proof structure 2, the first shaft seal 9 provides the first seal, and the closed housing 21 provides the second seal. Even if the first shaft seal 9 is damaged, the gas will not diffuse into the atmosphere within the buffer chamber 23. The leak discharge mechanism 25 is triggered by pressure, and when the medium leaks... The automatic opening of the negative pressure circuit 26 returns the leaked medium to the fan body 4, preventing corrosion buildup. Simultaneously, the magnetic coupling drives the fan shaft to rotate, isolating the motor and preventing it from malfunctioning due to corrosion. The entire fan fully meets the requirements of zero leakage and long-term normal operation. On the other hand, when the first shaft seal 9 is damaged and leaks, the leakage discharge mechanism 25 automatically opens the partition plate 22, allowing the cooling nitrogen in the protection chamber 24 to automatically replenish the buffer chamber 23. This quickly pushes the medium from the buffer chamber 23 into the fan body 4, accelerating the discharge of the medium. This creates a safe and clean local environment for maintenance, greatly improving the operation and maintenance response speed and personnel safety, and reducing unplanned downtime and high maintenance costs caused by corrosive medium leaks.

[0031] The impeller shaft end of the fan body 4 and the connection between the closed cover 21 are provided with a first shaft seal 9, and the connection between the connecting shaft 5 and the partition plate 22 is provided with a second shaft seal 10. The structure of the first shaft seal 9 and the second shaft seal 10 enhances the basic sealing performance. The first shaft seal 9 is for the core sealing surface between the fan body 4 and the closed cover 21, and the second shaft seal 10 is for the isolation surface between the buffer chamber 23 and the protective chamber 24. The double protection greatly reduces the risk of leakage.

[0032] The leakage discharge mechanism 25 includes a fixed cylinder 251. The left side of the fixed cylinder 251 is fixedly connected to the negative pressure circuit 26 via a pipeline. A movable seat 252 is slidably disposed inside the fixed cylinder 251, and a connecting rod 253 is welded to the bottom of the movable seat 252. A sealing seat 254 is welded to the bottom of the connecting rod 253, and the surface of the sealing seat 254 is in close contact with the inner wall of the fixed cylinder 251. A fixed seat 255 is threadedly disposed at the top of the fixed cylinder 251, and a pressure seat 256 is slidably disposed at the bottom of the fixed seat 255. A return spring 257 is disposed inside the movable seat 252, and the other end of the return spring 257 abuts against the pressure seat 256. A disconnect component 258 is disposed on the left side inside the fixed seat 255. The disconnect component 258 is electrically connected to the controller of the drive motor 3. By setting up the leakage discharge mechanism 25, the pressure in the buffer chamber 23 is stable during normal operation, and the movable seat 252... Under the action of the return spring 257, the sealing seat 254 is in the closed position and seals the lower end of the fixed cylinder 251. When the first shaft seal 9 fails and harmful gas leaks into the buffer chamber 23, causing its pressure to rise, the air pressure pushes the moving seat 252 to move upward against the force of the return spring 257. The moving seat 252 moves upward and first cuts off the power to the drive motor 3 through the disconnect component 258, realizing automatic shutdown. Then the sealing seat 254 leaves the lower end opening of the fixed cylinder 251, so that the buffer chamber 23 is connected to the negative pressure circuit 26. The leaked gas is sucked in and discharged back to the process system under the negative pressure of the air outlet pipe of the blower body 4. It can directly convert the physical signal of leakage (pressure rise) into two consecutive protective actions. On the one hand, it can make the blower body 4 stop immediately to prevent the continuous operation under fault conditions from causing greater damage. On the other hand, it can automatically open the discharge path, actively guide the leaked medium, and avoid the infinite accumulation of pressure in the buffer chamber 23.

[0033] The disconnect component 258 includes a movable column 258a, which is slidably disposed inside the fixed base 255. The bottom of the movable column 258a is fixedly connected to the movable base 252. A connecting terminal 258b is threadedly connected to the left side inside the fixed base 255. A stationary contact 258d is welded to the bottom of the connecting terminal 258b. A movable contact 258c is welded to the top of the movable column 258a. The movable contact 258c works in conjunction with the stationary contact 258d. By setting the disconnect component 258, when the pressure of the buffer chamber 23 pushes the movable base 252 upward, the movable column 258a fixed to it rises and falls accordingly. The movable contact 258c at the top of the movable column 258a contacts the stationary contact 258d connected to the fixed base 255, thereby cutting off the control circuit and stopping the operation of the drive motor 3 and the fan body 4, so that the staff can deal with the leakage in a timely manner.

[0034] The top of the pressure seat 256 is rotatably contacted with an adjusting screw 11, which is threaded into the interior of the fixed seat 255. By adjusting the screw 11, the trigger pressure of the leakage discharge mechanism 25 can be flexibly adjusted to adapt to different media pressures and different leakage risk levels, greatly improving the versatility of the device.

[0035] The partition plate 22 includes a pressure-bearing partition plate 221. A movable plate 222 is slidably disposed on the left side inside the pressure-bearing partition plate 221. Both the movable plate 222 and the pressure-bearing partition plate 221 have several air holes 223. A connecting frame 224 is rotatably connected to the top of the movable plate 222, and a connecting rod 225 is rotatably connected to the other end inside the connecting frame 224. The connecting rod 225 is slidably disposed inside the fixed seat 255, and the bottom of the connecting rod 225 is fixedly connected to the movable seat 252. A fixed frame 226 is rotatably sleeved on the surface of the connecting frame 224, and the top of the fixed frame 226 is connected to the enclosure. The inner wall of the shell 21 is bolted together. A fixed post 227 is welded to the bottom of the movable plate 222. A fixed sleeve 228 is provided at the bottom of the fixed post 227, and the bottom of the fixed sleeve 228 is bolted to the pressure-bearing partition 221. A retaining ring 229 and a blocking block 2210 are welded to the inner wall of the fixed sleeve 228 and the surface of the fixed post 227, respectively. The retaining ring 229 and the blocking block 2210 work together. By setting the partition plate 22, under normal conditions, the movable plate 222 is located in the upper part of the inside of the pressure-bearing partition 221. The air holes 223 on it are arranged alternately with the air holes 223 on the pressure-bearing partition 221. The gas between the two chambers... With the channel essentially blocked, when the leakage discharge mechanism 25 actuates and the movable seat 252 moves upward, the linkage mechanism consisting of the connecting rod 225 and the connecting frame 224 drives the movable plate 222 to slide downward in the guide slot. After the movable plate 222 descends to a certain position, its vent 223 gradually aligns with the vent 223 of the pressure-bearing partition 221, forming a connecting channel. At the same time, the fixing post 227 at the bottom of the movable plate 222 inserts into the fixing sleeve 228, and the retaining ring 229 on the surface of the fixing post 227 and the blocking block 2210 inside the fixing sleeve 228 form a mutually engaging structure to prevent the movable plate 222 from accidentally moving. The movement affects the connection of the vent 223; at this time, the positive pressure nitrogen gas maintained in the protective chamber 24 (replenished by the small gas storage tank 14 and maintained by the shutdown of the circulating heat dissipation system) can flow into the buffer chamber 23 through the aligned vent 223, perform flushing and replacement of the leaked residual harmful gas, and can quickly push the harmful gas into the casing of the fan body 4, which is convenient for subsequent maintenance and treatment of the leaked part; after maintenance is completed, the moving seat 252 is reset under the elastic action of the reset spring 257, and the moving plate 222 is moved up and reset through the linkage mechanism, and the vent 223 is misaligned and closed again, restoring the isolation state of the two chambers.

[0036] The pressure-bearing baffle 221 has a guide groove on its left side. The movable plate 222 is slidably disposed inside the guide groove, and the fixed sleeve 228 is located at the bottom of the guide groove. The movable plate 222 and the air holes 223 on the pressure-bearing baffle 221 are staggered and evenly distributed in the vertical direction. The guide groove of the pressure-bearing baffle 221 provides sliding guidance for the movable plate 222, ensuring that the movable plate 222 moves smoothly and avoiding deviation that would cause the air holes 223 to not be accurately aligned. The staggered arrangement of the movable plate 222 and the air holes 223 on the pressure-bearing baffle 221 completely blocks the buffer chamber 23 and the protective chamber 24 under normal conditions. When leakage occurs, the movable plate 222 slides to the position where the air holes 223 are aligned, forming a connecting channel. The air holes 223 are evenly distributed in the vertical direction, ensuring that the pressure in the chamber is uniformly balanced and the medium flows smoothly.

[0037] Both the fixing sleeve 228 and the blocking block 2210 are made of elastic material. The fixing sleeve 228 has several expansion notches in a ring shape inside, and the top of the fixing sleeve 228 has a guide bevel. By using elastic material and having expansion notches, the inner diameter of the fixing sleeve 228 has a certain elastic deformation capacity. When the fixing post 227 is inserted, the guide bevel guides it in, and the elastic inner wall provides friction constraint. Thus, the position of the movable plate 222 can be locked by the cooperation of the retaining ring 229 and the blocking block 2210, preventing the moving seat 252 from affecting the position of the movable plate 222 under pressure fluctuations, thereby ensuring the communication between the air holes 223.

[0038] The working principle of this embodiment is as follows: When the fan body 4 is running normally, the drive motor 3 drives the connecting shaft 5 and the impeller to rotate through the magnetic coupler 6. The first shaft seal 9 acts as the main seal, effectively isolating the harmful media inside the fan casing. At this time, the buffer chamber 23 and the protective chamber 24 inside the sealed cover 21 are physically isolated by the partition plate 22. In the partition plate 22, the movable plate 222 is located above the guide groove of the pressure-bearing partition plate 221, and the air holes 223 on it are arranged alternately with the air holes 223 on the pressure-bearing partition plate 221, completely blocking the communication between the two chambers. When the first shaft seal 9 fails and the harmful media leaks into the buffer chamber 23, the pressure inside the chamber gradually increases. This pressure acts on the bottom of the sealing seat 254. The pusher 254 and the movable seat 252 move upward against the spring force of the return spring 257. The upward movement of the movable seat 252 causes the movable column 258a to move upward synchronously, resulting in the moving contact 258c at the top of the movable column 258a contacting the stationary contact 258d. This cuts off the control circuit of the drive motor 3, causing the fan body 4 to stop operating immediately and preventing the fault from spreading. At the same time, since the other end of the negative pressure circuit 26 is connected to the negative pressure area of ​​the air outlet pipe of the fan body 4, the harmful gas leaked into the buffer chamber 23 is automatically drawn in and safely returned to the process system inside the fan casing via the negative pressure circuit 26, preventing the harmful medium from accumulating in the buffer chamber 23. As the movable seat 252 moves upward, the fixed... The connecting rod 225 fixed thereon drives the left end of the connecting frame 224 to move upward and the right end of the connecting frame 224 to move downward, thereby driving the movable plate 222 to slide downward in the guide groove of the pressure-bearing partition 221. When the movable plate 222 slides to a specific position, the air hole 223 on it is completely aligned with the air hole 223 on the pressure-bearing partition 221, establishing a connected purification channel between the buffer chamber 23 and the protective chamber 24. At the same time, the fixing post 227 at the bottom of the movable plate 222 is inserted into the elastic fixing sleeve 228 at the bottom. The retaining ring 229 on the inner wall of the fixing sleeve 228 and the blocking block 2210 on the surface of the fixing post 227 engage, locking the movable plate 222 in this connected position; at this time, the protective... The positive pressure nitrogen maintained by the circulating heat dissipation mechanism 8 and supplemented by the small gas storage tank 14 in the protective cavity 24 quickly flows into the buffer cavity 23 through the aligned air holes 223. This clean nitrogen forms a directional airflow, which further "pushes out" the harmful gases remaining around the first shaft seal 9 and the dead corners of the buffer cavity 23, and discharges them through the opened negative pressure circuit 26, thereby quickly purifying the buffer cavity 23 and creating a safe and clean working environment for subsequent maintenance personnel. After maintenance is completed, the reset leakage discharge mechanism 25 is reset, and each component moves in the opposite direction under the action of the reset spring 257. The movable plate 222 moves up and resets, the air holes 223 are repositioned, and the system returns to the initial sealed isolation state.

[0039] Example 2

[0040] refer to Figure 8 and 9A fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling also includes a circulating heat dissipation mechanism 8. The anti-leakage structure 2 further includes the circulating heat dissipation mechanism 8, which comprises an outer cooling jacket 81 and an inner cooling jacket 82. Both the outer cooling jacket 81 and the inner cooling jacket 82 are coaxially sleeved on the surface of the magnetic coupler 6 inside the enclosed housing 21. A cooling channel 83 is formed between the outer cooling jacket 81 and the inner cooling jacket 82. Guide rings 84 are welded to the left sides of both the outer cooling jacket 81 and the inner cooling jacket 82. A sealing plate 85 is welded between the left sides of the two guide rings 84. The sealing plate 85 has several annularly arranged spray holes 86 inside. Spiral guide protrusions 87 are welded to the inner wall of the outer cooling jacket 81. Heat dissipation fins 88 are welded to the stationary shell surface of the magnetic coupler 6 inside the enclosed housing 21. The heat dissipation fins 88 cooperate with the inner cooling jacket 82, and the circulating heat dissipation mechanism 83 works in conjunction with the inner cooling jacket 82. The heat dissipation mechanism 8 is coaxially sleeved on the surface of the magnetic coupler 6 via an outer cooling jacket 81 and an inner cooling jacket 82, forming a closed cooling channel 83 between them. The threaded guide protrusions on the inner wall of the outer cooling jacket 81 cause the low-temperature nitrogen to flow in a spiral within the channel, extending the heat exchange time. Meanwhile, the heat dissipation fins 88 on the surface of the magnetic coupler 6 increase the heat dissipation area and fit tightly with the inner cooling jacket 82, efficiently transferring heat to the low-temperature nitrogen. Furthermore, the guide ring 84 cooperates with the sealing plate 85, allowing the low-temperature nitrogen to be sprayed onto the bearing seat 7 through the injection holes 86 of the sealing plate 85, thus dissipating heat from the bearing seat 7. After absorbing heat within the channel, the low-temperature nitrogen flows through the shell-and-tube heat exchanger 12 for cooling and then returns to the protective chamber 24 via the circulating pump 13, forming a closed-loop heat dissipation system. This system effectively dissipates the heat generated by the high-speed operation of the magnetic coupler 6 and the bearing seat 7, ensuring the long-term stable operation of the magnetic coupler 6 and the bearing seat 7.

[0041] The top of the enclosed casing 21 is bolted with a shell-and-tube heat exchanger 12. The left side of the shell-and-tube heat exchanger 12 is fixedly connected to a circulation pump 13 via a pipeline, and the input end of the circulation pump 13 is connected to the protective cavity 24. The shell-and-tube heat exchanger 12 and the outer cooling jacket 81 are fixedly connected via a pipeline. The top of the enclosed casing 21 is bolted with a small gas storage tank 14 connected to it, and an electrically controlled valve is provided at the connection between the small gas storage tank 14 and the enclosed casing 21. The circulation pump 13 extracts the nitrogen gas with increased temperature in the protective cavity 24 and delivers it to the shell-and-tube heat exchanger 12. In the heat exchanger, the nitrogen gas exchanges heat with the cooling water (or air) on the shell side, and the temperature decreases. The cooled nitrogen gas is then pumped back into the inlet of the circulating heat dissipation mechanism 8 to start a new cycle. The small gas storage tank 14 serves as a pressure buffer and supplementary gas source, providing additional gas supply during the harmful gas purification stage.

[0042] The working principle of this embodiment is as follows: The circulating pump 13 starts, drawing nitrogen gas, which has been heated through heat exchange in the protective chamber 24, from the pump's input end. This gas is pumped to the shell-and-tube heat exchanger 12. Inside the shell-and-tube heat exchanger 12, the high-temperature nitrogen gas flows through the tubes and undergoes efficient heat exchange with the factory circulating cooling water (or air) flowing in the shell side. The nitrogen gas temperature drops significantly, becoming low-temperature nitrogen gas again. The cooled low-temperature nitrogen gas flows out from the outlet of the shell-and-tube heat exchanger 12 and is transported through pipelines to the inlet of the circulating heat dissipation mechanism 8, namely the annular cooling channel 83 formed between the outer cooling jacket 81 and the inner cooling jacket 82. After entering this channel, the nitrogen gas is guided by the spiral guide protrusions 87 welded to the inner wall of the outer cooling jacket 81, and does not move in a straight line but flows along a spiral path, prolonging the flow path and heat exchange time of the nitrogen gas in the channel. During the flow, the low-temperature nitrogen gas continuously undergoes convective heat exchange with the inner wall of the inner cooling jacket 82. The heat generated during the operation of the magnetic coupler 6... The nitrogen gas is efficiently transferred to the flowing nitrogen gas through the heat dissipation fins 88 and the inner cooling jacket 82 to cool the magnetic coupler 6. After completing the spiral heat exchange, the nitrogen gas flows to the left end of the cooling channel 83 and gathers in the space enclosed by two guide rings 84 and the sealing plate 85. Then, the nitrogen gas is ejected at a certain speed and flow rate through multiple injection holes 86 distributed in a ring on the sealing plate 85. These nitrogen gas jets directly impact the bearing housing 7 area, effectively impacting and cooling the frictional heat generated during its operation. The nitrogen gas that has completed all the cooling tasks has increased in temperature and then diffuses and mixes into the main space of the protective cavity 24. The circulating pump 13 extracts the nitrogen gas with increased temperature again and starts a new round of "heat exchange-cooling-heat absorption" cycle. During this process, the small gas storage tank 14, as a system pressure balancing unit, is connected to the protective cavity 24 through an electronically controlled valve. When additional gas is needed for purification after a leak, nitrogen gas is automatically replenished to ensure a sufficient supply of purified gas in the protective cavity 24.

[0043] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. Those skilled in the art can make modifications to this embodiment without contributing any inventive step after reading this specification. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling, comprising a mounting bracket (1), characterized in that: The top of the mounting bracket (1) is bolted with a leak-proof structure (2) and a drive motor (3), and the front side of the leak-proof structure (2) is bolted with a fan body (4), and the impeller shaft end of the fan body (4) is bolted with a connecting shaft (5), and the right end of the connecting shaft (5) and the output end of the drive motor (3) are both provided with magnetic couplers (6), the surface of the connecting shaft (5) is fitted with a bearing seat (7), and the bottom of the bearing seat (7) is bolted to the leak-proof structure (2); The leak-proof structure (2) includes a closed cover (21). A partition plate (22) is bolted to the left side inside the closed cover (21). The partition plate (22) divides the two sides inside the closed cover (21) into a buffer chamber (23) and a protective chamber (24). A leak discharge mechanism (25) is provided inside the buffer chamber (23). The output end of the leak discharge mechanism (25) is fixedly connected to a negative pressure circuit (26). The other end of the negative pressure circuit (26) is fixedly connected to the air outlet pipe of the fan body (4). The leak discharge mechanism (25) is used in conjunction with the partition plate (22).

2. The fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling according to claim 1, characterized in that: The impeller shaft end of the fan body (4) and the connection between the closed cover (21) are provided with a first shaft seal (9), and the connection between the connecting shaft (5) and the partition plate (22) is provided with a second shaft seal (10).

3. The fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling according to claim 1, characterized in that: The leakage discharge mechanism (25) includes a fixed cylinder (251). The left side of the fixed cylinder (251) is fixedly connected to the negative pressure circuit (26) through a pipeline. A movable seat (252) is slidably arranged inside the fixed cylinder (251), and a connecting rod (253) is welded to the bottom of the movable seat (252). A sealing seat (254) is welded to the bottom of the connecting rod (253), and the surface of the sealing seat (254) is in close contact with the inner wall of the fixed cylinder (251). A fixed seat (255) is threadedly arranged at the top of the fixed cylinder (251), and a pressure seat (256) is slidably arranged at the bottom of the fixed seat (255). A return spring (257) is arranged inside the movable seat (252), and the other end of the return spring (257) abuts against the pressure seat (256). A disconnect component (258) is arranged on the left side inside the fixed seat (255), and the disconnect component (258) is electrically connected to the controller of the drive motor (3).

4. A fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling as described in claim 3, characterized in that: The disconnecting assembly (258) includes a movable column (258a) which is slidably disposed inside a fixed base (255). The bottom of the movable column (258a) is fixedly connected to the movable base (252). A connecting terminal (258b) is threadedly connected to the left side inside the fixed base (255). A stationary contact (258d) is welded to the bottom of the connecting terminal (258b). A moving contact (258c) is welded to the top of the movable column (258a). The moving contact (258c) works in conjunction with the stationary contact (258d).

5. A fully enclosed, zero-leakage centrifugal fan with an externally mounted motor, driven by magnetic coupling, as described in claim 3, characterized in that: The top of the pressure seat (256) is in rotatable contact with an adjusting screw (11), and the adjusting screw (11) is threaded into the interior of the fixed seat (255).

6. A fully enclosed, zero-leakage centrifugal fan with an externally mounted motor, driven by magnetic coupling, as described in claim 3, characterized in that: The partition plate (22) includes a pressure-bearing partition plate (221). A movable plate (222) is slidably disposed on the left side inside the pressure-bearing partition plate (221). Both the movable plate (222) and the pressure-bearing partition plate (221) have several air holes (223) inside. A connecting frame (224) is rotatably connected to the top of the movable plate (222), and a connecting rod (225) is rotatably connected to the other end inside the connecting frame (224). The connecting rod (225) is slidably disposed inside the fixed seat (255), and the bottom of the connecting rod (225) is fixedly connected to the movable seat (252). The surface of the connecting frame (224) is rotatably fitted with a fixed frame (226), and the top of the fixed frame (226) is bolted to the inner wall of the closed cover (21). The bottom of the movable plate (222) is welded with a fixed column (227), and the bottom of the fixed column (227) is provided with a fixed sleeve (228), and the bottom of the fixed sleeve (228) is bolted to the pressure-bearing partition (221). The inner wall of the fixed sleeve (228) and the surface of the fixed column (227) are respectively welded with a retaining ring (229) and a blocking block (2210), and the retaining ring (229) and the blocking block (2210) are used in conjunction.

7. A fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling as described in claim 6, characterized in that: The pressure-bearing partition (221) has a guide groove on its left side. The movable plate (222) is slidably disposed inside the guide groove, and the fixed sleeve (228) is located at the bottom of the guide groove. The movable plate (222) and the air holes (223) on the pressure-bearing partition (221) are staggered and evenly distributed along the vertical direction.

8. A fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling as described in claim 6, characterized in that: Both the fixing sleeve (228) and the blocking block (2210) are made of elastic material. The interior of the fixing sleeve (228) has several expansion notches in a ring shape, and the top of the fixing sleeve (228) is provided with a guide bevel.

9. A fully enclosed, zero-leakage centrifugal fan with an externally mounted motor driven by magnetic coupling as described in claim 1, characterized in that: The leak-proof structure (2) also includes a circulating heat dissipation mechanism (8), which includes an outer cooling sleeve (81) and an inner cooling sleeve (82). The outer cooling sleeve (81) and the inner cooling sleeve (82) are coaxially sleeved on the surface of the magnetic coupler (6) inside the closed cover (21). A cooling channel (83) is formed between the outer cooling sleeve (81) and the inner cooling sleeve (82). A guide ring (84) is welded to the left side of both the outer cooling sleeve (81) and the inner cooling sleeve (82). A sealing plate (85) is welded between the left sides of the two guide rings (84). The sealing plate (85) has several spray holes (86) arranged in a ring shape inside. A spiral guide protrusion (87) is welded to the inner wall of the outer cooling sleeve (81). A heat dissipation fin (88) is welded to the static shell surface of the magnetic coupler (6) inside the closed cover (21). The heat dissipation fin (88) is used in conjunction with the inner cooling sleeve (82).

10. A fully enclosed, zero-leakage centrifugal fan with an externally mounted motor, driven by magnetic coupling, as described in claim 1, characterized in that: A shell-and-tube heat exchanger (12) is bolted to the top of the enclosed casing (21). A circulating pump (13) is fixedly connected to the left side of the shell-and-tube heat exchanger (12) through a pipeline. The input end of the circulating pump (13) is connected to the protective cavity (24). The shell-and-tube heat exchanger (12) is fixedly connected to the outer cooling jacket through a pipeline. A small gas storage tank (14) connected to the top of the enclosed casing (21) is bolted to it. An electrically controlled valve is provided at the connection between the small gas storage tank (14) and the enclosed casing (21).

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