Corrosion-resistant circulating pump with quick-change sealing structure

Abstract

This invention discloses a corrosion-resistant circulating pump with a quick-change seal structure, comprising a base, a pump housing, a motor, and an integrated sealing assembly connecting the pump housing and the motor. An impeller shaft is supported within the pump housing by a ceramic bearing. One end of the impeller shaft is fixed to the impeller, and the other end has a first connecting portion. The integrated sealing assembly includes a sealing housing, an intermediate drive shaft passing through the sealing housing, and a mechanical seal installed between the two. One end of the intermediate drive shaft has a second connecting portion that inserts into the first connecting portion, and the other end is connected to the motor via a coupling. When the mechanical seal needs to be replaced, the integrated sealing assembly along with the intermediate drive shaft can be pulled out as a whole, separating the second connecting portion from the first connecting portion. This invention achieves rapid replacement of the entire sealing assembly. During the replacement process, the impeller shaft and impeller remain stationary, eliminating the need for realignment, significantly shortening maintenance time and improving repair efficiency.

Description

Technical Field

[0001] This invention relates to the field of chemical pump technology, and more specifically, to a corrosion-resistant circulating pump with a quick-change seal structure. Background Technology

[0002] Corrosion-resistant circulating pumps are used to transport corrosive and abrasion-resistant media. They are mainly used for transporting corrosive liquids and have stable and efficient transport performance. They are widely used in chemical, metallurgical, and mining industries.

[0003] Most existing corrosion-resistant circulating pumps use mechanical seals as shaft sealing devices. However, mechanical seals are one of the most easily damaged components in corrosion-resistant circulating pumps. Replacing a mechanical seal requires disassembling the motor, coupling, pump cover, impeller, and other components in sequence. The entire replacement process involves the disassembly and assembly of multiple parts, with numerous and complex steps, severely impacting maintenance efficiency.

[0004] Therefore, there is an urgent need for a corrosion-resistant circulating pump that can enable rapid replacement of seals. Summary of the Invention

[0005] To address the above deficiencies, this invention provides a corrosion-resistant circulating pump with a quick-change sealing structure to solve the aforementioned problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A corrosion-resistant circulating pump with a quick-change seal structure includes a base, a pump housing, and a motor. The pump housing and the motor are mounted on the base, and the pump pump housing and the motor also include an integrated sealing assembly connecting the pump housing and the motor. The impeller shaft is rotatably supported inside the pump housing by a corrosion-resistant bearing. One end of the impeller shaft is fixed with an impeller, and the other end is provided with a first connecting part. The integrated sealing assembly includes a sealing housing, an intermediate drive shaft, and a mechanical seal. The sealing housing is detachably and fixedly connected to the input end of the pump housing. The intermediate drive shaft is rotatably inserted into the sealing housing, and the mechanical seal is installed between the sealing housing and the intermediate drive shaft. The intermediate drive shaft has a second connecting part at one end that is axially inserted into the first connecting part, and a third connecting part at the other end. The rotating end of the motor is connected to the third connecting part of the intermediate transmission shaft via a coupling, and the coupling and the intermediate transmission shaft are axially inserted.

[0007] By adopting a "three-section shaft" structure (impeller shaft—intermediate drive shaft—motor shaft), the intermediate drive shaft is installed as an independent transmission component within the integrated sealing assembly. When the seal needs to be replaced, simply pull out the integrated sealing assembly along with the intermediate drive shaft as a whole, separating the second connection from the first connection, and the sealing assembly can be removed. During this process, the impeller shaft and impeller remain stationary, eliminating the need to disassemble the impeller and pump cover, or readjust the coaxiality. Operation time is reduced from the traditional 2-4 hours to 20-30 minutes, significantly shortening maintenance time and improving maintenance efficiency.

[0008] Preferably, the first connecting part is an internal spline hole at the center of the other end of the impeller shaft, and the second connecting part is a first spline shaft disposed at one end of the intermediate transmission shaft, wherein the first spline shaft is slidably inserted into the internal spline hole.

[0009] Spline connections can transmit large torques while allowing axial sliding, enabling the intermediate drive shaft to be easily pulled out from the impeller shaft end. The multi-tooth meshing structure of the spline ensures uniform load distribution and smooth transmission, making it suitable for high-torque, high-speed acid pump applications.

[0010] Preferably, a cylindrical guide boss is provided at the center of the inner spline hole, and a cylindrical guide hole that precisely matches the cylindrical guide boss is provided on the first spline shaft.

[0011] The precise fit between the cylindrical guide boss and the cylindrical guide hole ensures that during the insertion of the intermediate drive shaft, the spline teeth engage first, followed by the mating of the cylindrical guide boss and the cylindrical guide hole, providing radial positioning of the spline connection and further guaranteeing the coaxiality of the intermediate drive shaft and the impeller shaft. This structure effectively compensates for the impact of spline tooth backlash on coaxiality, reduces spline wear and eccentricity issues caused by repeated insertion and removal, and ensures the fitting accuracy of the sealing end faces.

[0012] Preferably, the coupling is a flange-type coupling, comprising: An active flange is mounted on the drive shaft of the drive motor; The driven flange is detachably fixed to the driving flange by a bolt assembly; The third connecting part of the intermediate drive shaft is a second spline shaft; The second splined shaft is slidably inserted into the splined groove of the driven flange and can be pulled out from the splined groove axially.

[0013] This flange-type coupling structure achieves two-stage separability: removing the bolt assembly allows the driven flange to separate from the driving flange; a pull-out action allows the second splined shaft to slide out of the spline groove, thus achieving complete separation of the intermediate drive shaft from the motor. This structure ensures reliable torque transmission while providing operational space for the complete removal of the sealing assembly.

[0014] During disassembly: After removing the bolts from the integrated sealing assembly to the pump housing input end, move the integrated sealing assembly along with the intermediate drive shaft in the direction of the motor. At this time, the second splined driven flange is inserted into the spline groove, and the first splined shaft is moved out of the inner splined hole. Then remove the driven flange, and the integrated sealing assembly along with the intermediate drive shaft can be completely removed from the second splined shaft end.

[0015] Preferably, the pump housing has a first flange at the input end, and the pump housing inner wall and the end face of the first flange are provided with an integrally formed first anti-corrosion lining layer. The sealing housing is provided with a second flange, and the inner wall of the sealing housing and the end face of the second flange are provided with an integrally formed second anti-corrosion lining layer; The first flange and the second flange are fastened together by bolts, and an anti-corrosion sealing gasket is sandwiched between them.

[0016] The system employs a flange-connected structure, with the anti-corrosion lining of both flanges extending to the flange end faces. Connected by anti-corrosion sealing gaskets, it forms a continuous anti-corrosion barrier from the inner wall of the pump chamber to the inner wall of the sealing shell. This structure ensures that all surfaces in contact with corrosive media are covered with anti-corrosion material, with no exposed metal, completely eliminating the possibility of corrosive media penetrating the metal substrate.

[0017] Preferably, the impeller shaft and the intermediate drive shaft are respectively composed of a metal base shaft, an anti-corrosion coating on the outer surface of the metal base shaft, and an anti-corrosion material covering the metal base shaft; an anti-corrosion sealing gasket or an O-ring is provided at the joint between the anti-corrosion material of the intermediate drive shaft and the impeller shaft.

[0018] The shaft employs a three-layer composite structure consisting of a metal substrate shaft, an anti-corrosion coating, and anti-corrosion materials. This structure ensures both the shaft's mechanical strength and reliable corrosion protection. The anti-corrosion coating, acting as the intermediate layer, enhances the bond between the anti-corrosion materials and the metal substrate. The anti-corrosion materials, as the outer layer, directly contact the medium and provide a sealed mounting surface. Seals are installed at the joints of the anti-corrosion materials on the shaft to prevent medium seepage through the joint gaps, forming a complete anti-corrosion system for the shaft.

[0019] Preferably, the integrated sealing assembly is configured such that, in the disassembled state, the impeller shaft and impeller remain stationary, and no readjustment of coaxiality is required.

[0020] Because the impeller shaft is independently supported within the pump housing by corrosion-resistant bearings, its rotation centerline remains unchanged during seal replacement. Therefore, there is no need to readjust the coaxiality of the motor and pump shaft after seal replacement, which not only significantly shortens maintenance time but also avoids seal wear problems caused by misalignment.

[0021] Preferably, the integrated sealing assembly is configured as a separate module that can be completely detached from the pump housing.

[0022] The integrated sealing assembly is a standalone module, pre-assembled and tested before leaving the factory. During on-site installation, it can be simply inserted as a whole and the bolts tightened. When replacing the seal, the old module is removed and the new module is installed, eliminating the need to disassemble and reassemble the individual parts of the mechanical seal on-site, greatly reducing the difficulty and time of on-site maintenance.

[0023] Preferably, the moving ring of the mechanical seal is mounted on the outer surface of the corrosion-resistant material of the intermediate drive shaft, and the corrosion-resistant material is configured as a sleeve-like structure for mounting the mechanical seal.

[0024] The anti-corrosion material on the outer surface of the intermediate drive shaft not only serves as corrosion protection but also directly acts as the mounting base for the mechanical seal's rotating ring, fulfilling the function of the bushing. This integrated design, combining corrosion protection, transmission, and sealing installation, reduces the number of parts, simplifies the structure, and avoids the clearance and corrosion risks between the bushing and shaft found in traditional solutions.

[0025] Preferably, the corrosion-resistant bearing is a ceramic bearing, specifically a silicon carbide ceramic bearing or a zirconia ceramic bearing.

[0026] Ceramic bearings (silicon carbide or zirconium oxide) possess excellent corrosion resistance and high hardness, enabling them to operate stably in acidic solutions for extended periods. Using ceramic bearings to directly support the impeller shaft eliminates the need for bearing housings and lubrication systems found in traditional solutions, resulting in simpler and more reliable impeller shaft support. This aligns with the design objective of this invention: "independent impeller shaft support that remains stationary during seal replacement." Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a corrosion-resistant circulating pump with a quick-change sealing structure according to the present invention; Figure 2 yes Figure 1 A magnified view of a section at point A in the middle; Figure 3 yes Figure 2 A schematic diagram of the disassembled integrated sealing assembly; Figure 4 This is an exploded view of the connection between the intermediate drive shaft and the impeller shaft; Figure 5 This is a side view of the first spline shaft; Figure 6 This is a side view of the second spline shaft; In the diagram: 1. Base; 2. Pump housing; 21. Impeller shaft; 211. First connecting part; 212. Cylindrical guide boss; 22. Corrosion-resistant bearing; 23. Impeller; 24. First flange; 25. First anti-corrosion liner; 3. Motor; 4. Integrated sealing assembly; 41. Sealing housing; 411. Second flange; 412. Second anti-corrosion liner; 413. Anti-corrosion gasket; 42. Intermediate drive shaft; 421. Second connecting part; 422. Cylindrical guide hole; 423. Third connecting part; 424. Metal base shaft; 425. Anti-corrosion coating; 426. Anti-corrosion material layer; 43. Mechanical seal; 431. Dynamic ring; 432. Stationary ring; 5. Coupling; 51. Driving flange; 52. Driven flange; 53. Spline groove. Detailed Implementation

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0029] It should be noted that the mechanical seal 43 in the accompanying drawings of this invention is a schematic diagram of the principle, and its axial length and specific shape are drawn only for ease of observation and do not represent the actual scale. The mechanical seal 43 can be a double-end mechanical seal, which specifically includes components such as a dynamic ring, a stationary ring, an elastic element, and an auxiliary sealing ring. The specific structure, interconnection relationship, and installation and disassembly method of these components are well known in the art and will not be described in detail here.

[0030] Example 1

[0031] See Figure 1 and Figure 3 A corrosion-resistant circulating pump with a quick-change seal structure includes a base 1, a pump housing 2, and a motor 3. The pump housing 2 and the motor 3 are respectively mounted on the base 1 by anchor bolts, and an operating space is left between the pump housing 2 and the motor 3 for disassembling and assembling the integrated seal assembly 4.

[0032] The pump housing 2 is made of gray cast iron or ductile iron. The inlet end of the pump housing 2 is connected to the integrated sealing assembly 4 by a flange. The pump housing 2 is provided with a medium inlet end and a medium outlet end, which are used to connect to the suction pipeline and the discharge pipeline, respectively. The inner wall of the pump housing 2 is provided with a pump body anti-corrosion lining layer, which is made of polytetrafluoroethylene (PTFE) or perfluoroethylene propylene copolymer (FEP), with a thickness of 3-5mm, and is bonded to the metal matrix of the pump housing 2 by hot pressing sintering process.

[0033] An impeller shaft 21 is rotatably supported within the pump housing 2 by a corrosion-resistant bearing 22. The corrosion-resistant bearing 22 is a ceramic bearing, specifically a silicon carbide (SiC) ceramic bearing or a zirconia (ZrO2) ceramic bearing. An impeller 23 is fixed to one end of the impeller shaft 21, and the impeller 23 is fixed to the impeller shaft 21 by a threaded connection or a key connection with a lock nut. The impeller 23 is made of fluoroplastic or fluoroplastic-coated metal inserts. A first connecting part 211 is provided at the other end of the impeller shaft 21.

[0034] The integrated sealing assembly 4 includes a sealing housing 41, an intermediate drive shaft 42, and a mechanical seal 43. The sealing housing 41 is a cylindrical component made of stainless steel or carbon steel. The sealing housing 41 is connected to the inlet end of the pump housing 2 via a flange and is detachably fixed by a bolt set. The inner wall of the sealing housing 41 is provided with a corrosion-resistant inner lining made of PTFE or FEP with a thickness of 3-5 mm.

[0035] An end cap is installed at one end of the sealing housing 41, and a bearing is installed inside the end cap. The intermediate drive shaft 42 is rotatably inserted into the sealing housing 41 through the bearing. One end of the intermediate drive shaft 42 is provided with a second connecting part 421 that is axially inserted into the first connecting part 211, and the other end is provided with a third connecting part 423. The mechanical seal 43 is installed between the sealing housing 41 and the intermediate drive shaft 42.

[0036] The mechanical seal 43 includes a rotating ring 431, a stationary ring 432, an elastic element, and auxiliary sealing rings. The materials of each component of the mechanical seal 43 (rotating ring, stationary ring, auxiliary sealing ring, spring, etc.) are selected from corrosion-resistant materials known in the art, based on the corrosiveness, temperature, and solids content of the conveyed medium, and will not be elaborated further here. The rotating ring 431 is mounted on the intermediate drive shaft 42, and the stationary ring 432 is mounted on the inner wall of the sealing housing 41 via a stationary ring seat. The rotating ring 431 is sealed to the intermediate drive shaft 42 by an O-ring, and the stationary ring 432 is sealed to the sealing housing 41 by an O-ring. The elastic element provides clamping force to keep the end faces of the rotating ring 431 and the stationary ring 432 in contact.

[0037] Motor 3 is a three-phase asynchronous motor, and its rotating end is equipped with a drive shaft. The drive shaft is connected to the third connecting part of the intermediate transmission shaft 42 through coupling 5, and the coupling and the intermediate transmission shaft 42 are axially inserted.

[0038] During normal operation, the motor 3 drives the intermediate transmission shaft 42 to rotate through the coupling 5. The intermediate transmission shaft 42 drives the impeller shaft 21 to rotate through the insertion and cooperation of the second connecting part 421 and the first connecting part 211, thereby driving the impeller 23 to rotate and realizing the transportation of the medium.

[0039] When the mechanical seal 43 needs to be replaced, first close the pump's inlet and outlet valves, drain the medium from the pump housing 2, and flush the pump chamber with clean water or neutral cleaning solution to remove any residual corrosive liquid. Then, simply remove the connecting bolts between the seal housing 41 and the pump housing 2, pull out the integrated seal assembly 4 as a whole, separating the second connecting part 421 from the first connecting part 211, and the integrated seal assembly 4 can be removed for replacement. During this process, the impeller shaft 21 and impeller 23 remain stationary, eliminating the need to disassemble the impeller and pump cover, or readjust the coaxiality, significantly improving maintenance efficiency.

[0040] Preferably, in this embodiment, the mechanical seal is a double-end mechanical seal, with an isolation cavity formed between the two pairs of sealing end faces. The isolation cavity is filled with coolant, and the sealing end faces of the moving ring 431 and the stationary ring 432 of the mechanical seal 43 are immersed in the coolant. The coolant directly carries away the heat generated by the friction of the sealing end faces, thus cooling the mechanical seal 43.

[0041] Example 2

[0042] See Figure 3 , Figure 4 and Figure 5 This embodiment optimizes the structure of the first connecting part 211 and the second connecting part 421 based on embodiment 1.

[0043] The first connecting part 211 is an internal spline hole located at the center of the other end of the impeller shaft 21. The spline teeth of the internal spline hole are rectangular teeth or involute teeth, and the number of teeth is determined according to the magnitude of the transmitted torque, generally 6-10 teeth. The internal spline hole is machined by broaching, with a surface hardness ≥ HRC45 and a surface roughness Ra ≤ 1.6 μm.

[0044] The second connecting part 421 is a first splined shaft located at one end of the intermediate drive shaft 42, which matches the inner splined hole. The first splined shaft is machined by gear hobbing or milling, with a surface hardness ≥ HRC50 and a surface roughness Ra ≤ 1.6 μm. The fit between the first splined shaft and the inner splined hole is a sliding fit with a clearance of 0.05-0.15 mm, facilitating axial insertion and removal.

[0045] A cylindrical guide boss 212 is provided at the center of the internal spline bore. The cylindrical guide boss 212 is an integral structure with the impeller shaft 21, or it is fitted into the center hole at the bottom of the internal spline bore through an interference fit. The ratio of the outer diameter of the cylindrical guide boss 212 to the inner diameter of the internal spline bore is 1:3 to 1:5, the length is 5-15 mm, the surface roughness Ra≤0.4 μm, and the cylindricity ≤0.005 mm. The front end of the cylindrical guide boss 212 is provided with a 15°-30° guide chamfer.

[0046] The first splined shaft is provided with a cylindrical guide hole 422 that precisely mates with the cylindrical guide boss 212. The cylindrical guide hole 422 is located at the central axis of the first splined shaft, and its diameter matches the outer diameter of the cylindrical guide boss 212, with a fit tolerance of H7 / h6 or H6 / h5 and a fit clearance of 0.005-0.015mm. The length of the cylindrical guide hole 422 matches the length of the cylindrical guide boss 212, and its surface roughness Ra≤0.4μm. An inlet chamfer is also provided at its entrance.

[0047] When the intermediate drive shaft 42 is inserted into the impeller shaft 21, the first spline shaft engages with the spline teeth of the inner spline hole. As insertion continues, the cylindrical guide boss 212 begins to enter the cylindrical guide hole 422. The precise fit between the cylindrical guide boss 212 and the cylindrical guide hole 422 provides radial positioning for the spline connection, compensating for radial offset caused by the side clearance of the spline teeth. Ultimately, the spline teeth are responsible for transmitting torque, while the cylindrical guide pair is responsible for precise centering; their functions are separated yet work together.

[0048] In this embodiment, the precise fit between the cylindrical guide boss 212 and the cylindrical guide hole 422 effectively compensates for the influence of the spline tooth side clearance on coaxiality, reduces spline wear and eccentricity problems caused by repeated insertion and removal, ensures the end face fit accuracy of the mechanical seal 43, and extends the seal service life.

[0049] Example 3

[0050] See Figure 2 , Figure 3 and Figure 6 This embodiment optimizes the specific structure of coupling 5 based on embodiment 1.

[0051] Coupling 5 is a flange type coupling, including driving flange 51 and driven flange 52.

[0052] The active flange 51 is fixedly installed on the drive shaft of the motor 3 by key connection or interference fit. The active flange 51 is made of 45 steel or 40Cr and its surface is treated with anti-rust treatment.

[0053] The driven flange 52 is detachably fixed to the driving flange 51 by a bolt assembly. The bolt assembly consists of 4-8 high-strength bolts with a strength grade of 8.8 or 10.9, and the nuts are equipped with anti-loosening washers or coated with anti-loosening adhesive. The driven flange 52 is made of the same material as the driving flange 51.

[0054] The third connecting part 423 of the intermediate drive shaft 42 is a second spline shaft. The second spline shaft and the intermediate drive shaft 42 are an integral structure, or are fixedly connected by welding or interference fit. The key teeth of the second spline shaft are rectangular teeth or involute teeth, with 6-10 teeth and a surface hardness ≥ HRC50.

[0055] The driven flange 52 is provided with a splined groove 53, the inner spline of which matches the outer spline of the second splined shaft. The second splined shaft is slidably inserted into the splined groove 53 and can be pulled out axially from the splined groove 53. The clearance of the spline fit is 0.05-0.15mm to facilitate axial sliding.

[0056] During normal operation, the active flange 51 is fastened to the driven flange 52 by bolts. When the motor 3 rotates, the driven flange 52 is driven to rotate by the active flange 51. The driven flange 52 drives the intermediate transmission shaft 42 to rotate by the spline groove 53 and the second spline shaft, which in turn drives the impeller shaft 21 and the impeller 23 to rotate.

[0057] When replacing the integrated sealing assembly 4, first remove the bolt group of the flange coupling to separate the driven flange 52 from the driving flange 51. Then remove the connecting bolts between the sealing housing 41 and the pump housing 2. Move the integrated sealing assembly 4 together with the intermediate drive shaft 42 towards the motor 3 as a whole. At this time, the second splined shaft is inserted into the spline groove 53 of the driven flange 52. Then remove the driven flange 52, and the integrated sealing assembly 4 together with the intermediate drive shaft 42 can be completely removed.

[0058] This embodiment implements a two-stage separable structure, which not only ensures reliable torque transmission but also provides operational space for the overall extraction of the sealing assembly.

[0059] Example 4

[0060] See Figure 1 , Figure 2 This embodiment optimizes the flange connection between the pump housing 2 and the integrated sealing assembly 4, based on embodiment 1.

[0061] The pump housing 2 has a first flange 24 at its inlet end. The inner wall of the pump housing 2 and the end face of the first flange 24 are provided with a first anti-corrosion lining layer 25. The first anti-corrosion lining layer 25 is made of the same material as the anti-corrosion lining layer of the pump body and is integrally formed.

[0062] The sealing housing 41 is provided with a second flange 411. The inner wall of the sealing housing 41 and the end face of the second flange 411 are provided with a second anti-corrosion lining layer 412. The second anti-corrosion lining layer 412 is made of the same material as the anti-corrosion lining layer of the housing and is integrally formed.

[0063] A corrosion-resistant sealing gasket 413 is sandwiched between the first flange 24 and the second flange 411. The corrosion-resistant sealing gasket 413 is a PTFE-coated gasket, that is, the inner core is flexible graphite or silicone rubber (2-3mm thick), and the outer layer is PTFE (0.5-1mm thick). The first flange 24 and the second flange 411 are fastened together by bolts, pressing the corrosion-resistant sealing gasket 413 between the first corrosion-resistant inner lining layer 25 and the second corrosion-resistant inner lining layer 412.

[0064] During assembly, the first flange 24 and the second flange 411 are fastened together by bolts. The end faces of the first anti-corrosion liner 25 and the second anti-corrosion liner 412 are mated together, and the anti-corrosion sealing gasket 413 is sandwiched between them. When the bolts are tightened, the clamping force causes the anti-corrosion sealing gasket 413 to undergo elastic deformation, filling the microscopic gap between the end faces of the two anti-corrosion liners and forming a reliable static seal.

[0065] This embodiment forms a continuous anti-corrosion barrier from the inner wall of the pump cavity to the inner wall of the sealing housing, ensuring that all surfaces in contact with corrosive media are covered by anti-corrosion material, preventing corrosive media from penetrating into the metal substrate.

[0066] Example 5

[0067] See Figure 2 and Figure 4 Based on Example 1, this embodiment optimizes the anti-corrosion structure of the impeller shaft 21 and the intermediate transmission shaft 42.

[0068] The impeller shaft 21 and the intermediate drive shaft 42 are respectively composed of a metal base shaft 424, an anti-corrosion coating 425 disposed on the outer surface of the metal base shaft, and an anti-corrosion material layer 426 covering the metal base shaft.

[0069] The metal substrate shaft 424 is made of stainless steel or carbon steel. The outer surface of the metal substrate shaft 424 is treated with degreasing and rust removal, followed by surface activation treatment to enhance the adhesion of the anti-corrosion coating 425.

[0070] The anti-corrosion coating 425 is a tungsten carbide (WC-Co) coating prepared by thermal spraying, with a coating thickness of 50-100 μm, a coating hardness ≥ HV1100, and a porosity ≤1%; or a nickel-phosphorus alloy (Ni-P) coating prepared by chemical plating, with a coating thickness of 20-50 μm, a phosphorus content of 8-12%, and a coating hardness ≥ HV500. The anti-corrosion coating 425 is sprayed or plated to cover the entire outer surface of the metal substrate shaft 424.

[0071] The anti-corrosion material layer 426 is made of PTFE or FEP, with a thickness of 1-5mm, and is applied to the outer surface of the anti-corrosion coating 425 using a heat-shrink tubing process or injection molding. When using heat-shrink tubing, a PTFE heat-shrink sleeve is fitted onto the metal substrate shaft 424, and heating causes the sleeve to shrink and fit tightly. When using injection molding, the metal substrate shaft 424 is placed in an injection mold, and molten PTFE or FEP material is injected; after cooling, a tight coating layer is formed. The outer surface of the anti-corrosion material layer 426 is machined to achieve the required dimensional accuracy and surface roughness (Ra≤0.8μm).

[0072] At the joint between the intermediate drive shaft 42 and the anti-corrosion material layer 426 of the impeller shaft 21, an anti-corrosion sealing gasket or an O-ring is provided. The sealing gasket is a PTFE gasket with a thickness of 0.5-1mm; the O-ring is made of fluororubber (FKM) or perfluoroether rubber (FFKM) with a cross-sectional diameter of 2-4mm.

[0073] The rotating ring 431 of the mechanical seal 43 is mounted on the outer surface of the anti-corrosion material layer 426 of the intermediate drive shaft 42. The rotating ring 431 is sealed to the anti-corrosion material layer 426 by an O-ring and can slide slightly axially. A spring seat is fixed to the outer surface of the anti-corrosion material layer 426, and a spring is fitted onto the outer surface of the anti-corrosion material layer 426, with one end abutting against the spring seat and the other end abutting against the rotating ring 431, providing axial clamping force to keep the end faces of the rotating ring 431 and the stationary ring 432 in contact.

[0074] During normal operation, the metal substrate shaft 424 provides mechanical strength and torque transmission capability. The anti-corrosion coating 425 serves as an intermediate layer, enhancing the bonding force between the anti-corrosion material layer 426 and the metal substrate shaft 424, while also providing a seepage prevention function. The anti-corrosion material layer 426 is in direct contact with the corrosive medium, protecting the internal metal from corrosion, while its outer surface serves as the mounting base for the dynamic ring of the mechanical seal 43.

[0075] This embodiment achieves an integrated design that combines corrosion protection, transmission, and sealed installation, reducing the number of parts and simplifying the structure.

[0076] The above technical solutions only embody the preferred technical solutions of the present invention. Any modifications that may be made by those skilled in the art to certain parts thereof embody the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A corrosion-resistant circulating pump with a quick-change seal structure, comprising a base, a pump housing, and a motor, wherein the pump housing and the motor are mounted on the base, characterized in that, It also includes an integrated sealing assembly connecting the pump housing and the motor; The impeller shaft is rotatably supported inside the pump housing by a corrosion-resistant bearing. One end of the impeller shaft is fixed with an impeller, and the other end is provided with a first connecting part. The integrated sealing assembly includes a sealing housing, an intermediate drive shaft, and a mechanical seal. The sealing housing is detachably and fixedly connected to the input end of the pump housing. The intermediate drive shaft is rotatably inserted into the sealing housing, and the mechanical seal is installed between the sealing housing and the intermediate drive shaft. The intermediate drive shaft has a second connecting part at one end that is axially inserted into the first connecting part, and a third connecting part at the other end. The rotating end of the motor is connected to the third connecting part of the intermediate transmission shaft via a coupling, and the coupling and the intermediate transmission shaft are axially inserted.

2. The corrosion-resistant circulating pump with a quick-change seal structure according to claim 1, characterized in that, The first connecting part is an internal spline hole at the center of the other end of the impeller shaft, and the second connecting part is a first spline shaft provided at one end of the intermediate transmission shaft, with the first spline shaft slidably inserted into the internal spline hole.

3. A corrosion-resistant circulating pump with a quick-change seal structure according to claim 2, characterized in that, A cylindrical guide boss is provided at the center of the inner spline hole, and a cylindrical guide hole that precisely matches the cylindrical guide boss is provided on the first spline shaft.

4. A corrosion-resistant circulating pump with a quick-change seal structure according to claim 1, characterized in that, The coupling is a flange-type coupling, including: An active flange is mounted on the drive shaft of the drive motor; The driven flange is detachably fixed to the driving flange by a bolt assembly; The third connecting part of the intermediate drive shaft is a second spline shaft; The second splined shaft is slidably inserted into the splined groove of the driven flange and can be pulled out from the splined groove axially.

5. A corrosion-resistant circulating pump with a quick-change seal structure according to claim 1, characterized in that: The pump housing is provided with a first flange at the input end, and the pump housing inner wall and the end face of the first flange are provided with an integrally formed first anti-corrosion lining layer. The sealing housing is provided with a second flange, and the inner wall of the sealing housing and the end face of the second flange are provided with an integrally formed second anti-corrosion lining layer; The first flange and the second flange are fastened together by bolts, and an anti-corrosion sealing gasket is sandwiched between them.

6. A corrosion-resistant circulating pump with a quick-change seal structure according to claim 1, characterized in that, The impeller shaft and the intermediate drive shaft are respectively composed of a metal base shaft, an anti-corrosion coating on the outer surface of the metal base shaft, and an anti-corrosion material covering the metal base shaft; an anti-corrosion sealing gasket or an O-ring is provided at the joint between the anti-corrosion material of the intermediate drive shaft and the impeller shaft.

7. A corrosion-resistant circulating pump with a quick-change seal structure according to claim 1, characterized in that, The integrated sealing assembly is configured such that, in the disassembled state, the impeller shaft and impeller remain stationary and do not require readjustment of coaxiality.

8. A corrosion-resistant circulating pump with a quick-change seal structure according to claim 1, characterized in that, The integrated sealing assembly is configured as a separate module that can be completely detached from the pump housing.

9. A corrosion-resistant circulating pump with a quick-change seal structure according to claim 6, characterized in that, The moving ring of the mechanical seal is mounted on the outer surface of the corrosion-resistant material of the intermediate drive shaft, and the corrosion-resistant material is configured as a bushing-like structure for mounting the mechanical seal.

10. A corrosion-resistant circulating pump with a quick-change seal structure according to claim 1, characterized in that, The corrosion-resistant bearing is a ceramic bearing, which is a silicon carbide ceramic bearing or a zirconia ceramic bearing.

Images