Magnetic drive pump for transporting tar

Abstract

This application discloses a magnetically driven pump for conveying tar, comprising a pump body with an impeller cavity, a pump inlet, a pump outlet, and a flushing fluid outlet; a pump cover; an open impeller; a drive shaft; a driven shaft, which is fixedly connected to the open impeller and has a hollow structure; an outer magnetic rotor fixedly connected to the drive shaft; an inner magnetic rotor that cooperates with the outer magnetic rotor and is fixedly connected to the driven shaft; an isolation sleeve, which is barrel-shaped and has its open end sealed and fixed to the pump cover and located between the outer magnetic rotor and the inner magnetic rotor; a flushing fluid inlet that communicates unidirectionally with the inner cavity of the isolation sleeve; and a circulation channel near the pump outlet that connects the inner cavity of the isolation sleeve and the impeller cavity, allowing cleaning fluid to be injected through the flushing fluid inlet when the pump is stopped without disassembling, effectively preventing circulation obstruction and poor lubrication caused by tar residue or debris accumulation.

Description

Technical Field

[0001] This utility model belongs to the field of pumping equipment technology, specifically relating to a magnetically driven pump for conveying tar. Background Technology

[0002] In the petrochemical and coking industries, coal tar is an important byproduct. Its formation primarily originates from the high-temperature dry distillation of coal, a process where coal undergoes complex chemical reactions such as pyrolysis and condensation under high temperature and air-isolated conditions to produce a liquid mixture. Coal tar is highly complex, containing a variety of aromatic compounds including phenols, naphthalenes, pyridines, and quinolines. These compounds interact in complex ways, giving coal tar its high viscosity, high density, and the potential presence of incompletely decomposed solid particles (such as coal tar particles and coke powder).

[0003] The high viscosity of tar primarily stems from the strong intermolecular forces formed by the stacking of numerous aromatic rings in its molecular structure. This structure not only increases the cohesive force of tar but also significantly increases its flow resistance during pipeline transportation and mechanical handling. Furthermore, solid particles in tar further exacerbate its flowability issues, as their presence creates tiny flow barriers in the fluid, hindering smooth flow and thus increasing the overall viscosity.

[0004] In terms of quantity, the yield of coal tar is often closely related to the type of raw coal and the conditions of the dry distillation process (such as temperature, pressure, and time), typically accounting for 3% to 5% of the raw coal mass, and even higher under certain special process conditions. This considerable yield makes the effective treatment and utilization of coal tar a key link in the petrochemical and coking industries.

[0005] In the petrochemical and coking industries, mechanically sealed pumps are frequently used to transport viscous, high-density media containing solid particles, such as tar. However, mechanically sealed pumps rely on mechanical seals to prevent media leakage. But when handling media like tar, the sealing surfaces of the mechanical seals are frequently subjected to adhesion of high-viscosity tar and accumulation of solid particles, leading to accelerated wear of the sealing surfaces, a significant decrease in sealing performance, and frequent tar leakage. This not only increases the number of equipment downtimes for maintenance, seriously affecting the continuity and efficiency of the production line, but also causes serious environmental pollution due to the uncontrollable diffusion rate and wide range of the leaked tar.

[0006] In addition, the internal structure of mechanical seal pumps, such as bearings, impellers, cooling channels and inner walls, is also very susceptible to tar adhesion. Especially in low-temperature environments, this tar adhesion makes it difficult to start the pump, usually requiring disassembly for cleaning, which further increases the maintenance burden and production costs of the equipment.

[0007] Therefore, there is a need for a pump that can effectively handle the high viscosity, high density, and solid particle content of tar, which is of great significance for improving the production efficiency and environmental protection level of the petrochemical and coking industries. Utility Model Content

[0008] To address some or all of the aforementioned technical problems in the existing technology, this utility model proposes a magnetically driven pump for conveying tar. This magnetically driven pump for conveying tar avoids the problem of frequent maintenance of tar pumps.

[0009] According to this utility model, a magnetically driven pump for conveying tar is provided, comprising:

[0010] The pump body includes an impeller cavity, a pump inlet located at the front end of the pump body and communicating with the impeller cavity, and a pump outlet located on the wall of the pump body and communicating with the impeller cavity. A flushing fluid outlet is located on the bottom wall of the pump body.

[0011] Pump cover, the pump cover being disposed at the rear end of the pump body,

[0012] An open impeller is disposed within the impeller cavity.

[0013] drive shaft,

[0014] A driven shaft, the front end of which passes through the pump cover and is fixedly connected to the open impeller, the driven shaft having a hollow structure.

[0015] An external magnetic rotor, which is fixedly connected to the drive shaft.

[0016] An inner magnetic rotor is configured to cooperate with the outer magnetic rotor, and the inner magnetic rotor is fixedly connected to the driven shaft.

[0017] An isolation sleeve, which is barrel-shaped and has its open end sealed and fixed to the pump cover, is disposed between the outer magnetic rotor and the inner magnetic rotor.

[0018] A flushing fluid inlet, which is unidirectionally connected to the inner cavity of the isolation sleeve.

[0019] A circulation channel connects the inner cavity of the isolation sleeve with the impeller cavity near the pump outlet.

[0020] As can be seen, this utility model adopts an open impeller, which facilitates the cleaning of tar and deposits and reduces maintenance costs; the isolation sleeve is sealed to the pump cover, completely isolating the drive side where the drive shaft is located from the tar, ensuring that the transported tar medium will not leak outwards; by adding an external flushing scheme, cleaning fluid can be injected into the pump without disassembling it when the pump is stopped, effectively preventing circulation obstruction and poor lubrication caused by tar residue or debris accumulation, thereby significantly improving the pump's working efficiency and operational stability.

[0021] In one embodiment, a heater is provided at the flushing fluid inlet. This heater heats the flushing fluid, increasing its temperature, improving the fluidity of the tar, and further enhancing the flushing effect.

[0022] In one embodiment, the drive shaft is mounted via a bearing housing, and a bracket, cylindrical in shape, is provided between the bearing housing and the pump cover to accommodate the external magnetic rotor. The insulation structure is provided on the outer sides of the pump body, pump cover, and bracket. This insulation structure keeps the pump body, pump cover, and bracket warm, ensuring that the temperature of the tar medium within the pump cavity remains within a stable temperature range and preventing temperature changes from affecting the fluidity of the tar medium.

[0023] In one embodiment, the insulation structure includes an insulation shell, a heating inlet pipe, and a heating outlet pipe. The insulation shell contains a venting cavity, and the insulation shell has a heating inlet and a heating outlet communicating with the venting cavity. The heating inlet pipe is connected to the heating inlet, and the heating outlet pipe is connected to the heating outlet. This design tightly wraps the pump body, pump cover, and bracket, effectively isolating the external environment from the temperature of the medium inside the pump. The venting cavity inside the insulation shell is used to contain and circulate hot steam, thereby achieving continuous insulation of the tar inside the pump. During the operation of the insulation structure, hot steam is introduced into the venting cavity through the heating inlet pipe. This hot steam is evenly distributed within the venting cavity, and the excellent insulation performance of the insulation shell reduces heat loss. Subsequently, the hot steam follows the path of the heating circulation loop and is discharged through the heating outlet pipe, completing the circulation. During this process, the hot steam exchanges heat with the tar inside the pump, effectively preventing the tar from solidifying in a low-temperature environment and ensuring the continuous and stable operation of the pump.

[0024] In one embodiment, the circulation channel is an internal circulation channel formed in the pump cover and the pump body. The internal circulation channel can guide the medium in the impeller cavity to the inner cavity of the isolation sleeve, and return it to the impeller cavity through the hollow inner cavity of the driven shaft, thereby carrying away the eddy current heat generated by the magnetic coupler.

[0025] In one embodiment, the circulation channel is an external circulation channel, with one end connected to the pump outlet and the other end connected to the flushing fluid inlet. The external circulation channel not only efficiently utilizes the high-pressure liquid at the pump outlet, introducing it into the inner cavity of the isolation sleeve to effectively remove the eddy current heat generated during magnetic coupling operation, ensuring stable operation of the magnetically driven pump for conveying tar; simultaneously, since the external circulation channel is located outside the pump body, its design size is no longer limited by the internal space of the pump body, allowing for a more spacious design. This significantly reduces the risk of blockage by viscous media such as tar, further improving the cooling effect and extending the service life of the equipment.

[0026] In one embodiment, the impeller further includes a front wear-resistant plate and a rear wear-resistant plate, which are fixed inside the impeller cavity and located on the front and rear sides of the open impeller, respectively. As auxiliary support and protective structures for the open impeller, the front and rear wear-resistant plates effectively reduce friction and wear between the impeller and the pump body wall during high-speed rotation. This is particularly important because viscous media such as tar may contain solid particles or impurities, which, driven by the impeller, can exacerbate friction with the pump body wall, leading to wear and damage. The presence of the front and rear wear-resistant plates provides a smoother, more wear-resistant working environment for the impeller, extending the pump's service life.

[0027] In one embodiment, the front wear-resistant plate is bolted to the pump body, and the rear wear-resistant plate is bolted to the pump cover. This setup is simple and easy to implement, especially facilitating replacement if the front or rear wear-resistant plate is worn or damaged.

[0028] In one embodiment, the intermediate section of the driven shaft is mounted within the pump cover via a sliding bearing assembly and a thrust bearing assembly. The bearing assembly improves rotational accuracy, increases the load-bearing capacity of the driven shaft, and extends its service life.

[0029] In one embodiment, an elastic sleeve is further included, which is sleeved over the driven shaft and located between the sliding bearing assembly and the driven shaft. This elastic sleeve provides cushioning and protection for the sliding bearing assembly.

[0030] Compared with the prior art, the advantages of this utility model are as follows: This utility model adopts an open impeller, which facilitates the cleaning of tar and deposits and reduces maintenance costs; the isolation sleeve is sealed to the pump cover, completely isolating the drive side from the tar, ensuring that the transported tar medium will not leak outwards; by setting a flushing fluid inlet and flushing fluid outlet, an external flushing scheme is added, which allows cleaning fluid to be injected into the pump without disassembling it when the pump is stopped, effectively preventing circulation obstruction and poor lubrication caused by tar residue or debris accumulation, thereby significantly improving the pump's working efficiency and operational stability. Attached Figure Description

[0031] The preferred embodiments of this utility model will now be described in detail with reference to the accompanying drawings, in which:

[0032] Figure 1 This is a cross-sectional structural schematic diagram of a magnetically driven pump according to an embodiment of the present invention;

[0033] Figure 2 This is a cross-sectional structural schematic diagram of a magnetically driven pump according to another embodiment of the present invention.

[0034] The accompanying drawings are not drawn to scale. Detailed Implementation

[0035] To make the technical solution and advantages of this utility model clearer, the exemplary embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not an exhaustive list of all embodiments. Furthermore, without conflict, the embodiments and features in the embodiments of this utility model can be combined with each other.

[0036] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and do not imply any priority in order or any specific technical meaning. Furthermore, the concepts of "connection" and "linkage" mentioned in this application, unless otherwise specified, are considered to include both direct connection (linkage) and indirect connection (linkage).

[0037] When interpreting the description in this application, it is important to clarify that terms such as "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating directions or positional relationships, are based on the perspective and layout shown in the accompanying drawings. These terms are intended to facilitate explanation and simplify the description process, and are not absolute limitations on the actual location, construction method, or operating mode of the device or component. Therefore, these terms should not be construed as restrictive interpretations of the content of this application.

[0038] An embodiment of this utility model provides a magnetically driven pump for conveying tar. For example... Figure 1As shown, the magnetically driven pump for conveying tar includes a pump body 1, an open impeller 3, a pump cover 5, a driven shaft 6, a sliding bearing assembly 7, a thrust bearing assembly 10, an inner magnetic rotor 11, an isolation sleeve 12, an outer magnetic rotor 13, a drive shaft 8, a bracket 20, and a bearing housing 14. The pump body 1 has an impeller cavity 23. A pump inlet 21 is provided at the front end of the pump body 1 for communication with the impeller cavity 23. A pump outlet 22 is provided at the top of the pump body 1, also communicating with the impeller cavity 23. The pump cover 5 is located at the rear end of the pump body 1. The bracket 20 is connected to the rear end of the pump cover 5. The bearing housing 14 is located at the rear end of the bracket 20. The bracket 20 is cylindrical, and its inner cavity forms a rotor cavity. The inner magnetic rotor 11, the isolation sleeve 12, and the outer magnetic rotor 13 are all located within the rotor cavity. The open impeller 3 is mounted at the front end of the driven shaft 6 and located within the impeller cavity 23. The driven shaft 6 passes through the pump cover 5 and connects to the inner magnetic rotor 11. The outer magnetic rotor 13 is mounted on the drive shaft 8. The outer magnetic rotor 13 is matched with the inner magnetic rotor 11. The drive shaft 8 is mounted through the bearing housing 14. The isolation sleeve 12 is installed between the inner magnetic rotor 11 and the outer magnetic rotor 13. The isolation sleeve 12 is barrel-shaped, and its open end is sealed to the pump cover 5. The inner cavity of the isolation sleeve 12 forms a receiving cavity for accommodating the inner magnetic rotor 11. According to this application, the magnetically driven pump for conveying tar also includes a circulation channel. The inner cavity of the isolation sleeve 12 (i.e., the receiving cavity) is connected to the impeller cavity 23 through the circulation channel, and one end of the circulation channel is close to the pump outlet. At the same time, the hollow inner cavity of the driven shaft 6 connects the impeller cavity and the inner cavity of the isolation sleeve 12. A flushing fluid inlet 17 is provided at the bottom of the pump cover 5. The flushing fluid inlet 17 is used to connect to the external flushing pipeline. At the same time, the flushing fluid inlet 17 is connected to the inner cavity of the isolation sleeve 12. The flushing fluid inlet 17 is a one-way connection. Specifically, the flushing fluid inlet 17 allows flushing fluid to enter the interior of the pump cover 5 from the external flushing pipeline, but does not allow fluid to exit from the pump cover 5 through the flushing fluid inlet 17. A flushing fluid outlet 18 is provided at the bottom of the pump body 1. After the magnetically driven pump for conveying tar stops pumping tar, the cleaning operation can begin. During cleaning, flushing fluid is pumped through the external flushing pipeline, and then transported into the pump through the flushing fluid inlet 17. Once inside, the flushing fluid first enters the inner cavity of the isolation sleeve 12, then flows through the circulation channel and the hollow inner cavity of the driven shaft 6, finally reaching the impeller cavity 23. During this process, the inner cavity of the isolation sleeve 12, the circulation channel, and the hollow inner cavity of the driven shaft 6 are all thoroughly flushed by the flushing fluid. Finally, the flushing fluid is discharged from the flushing fluid outlet 18, completing the entire flushing process.

[0039] The rinsing fluid can be clean, free of impurities, and highly fluid pure tar.

[0040] A heater 19 is also provided at the flushing fluid inlet 17. The heater 19 can heat the flushing fluid, increase the temperature of the flushing fluid, thereby increasing the fluidity of the tar and further improving the flushing effect.

[0041] The magnetic drive pump for conveying tar also includes a heat insulation structure (not shown in the figure). The heat insulation structure is used to ensure that the temperature of the tar medium in the pump chamber is maintained within a stable temperature range, preventing temperature changes from affecting the fluidity of the tar medium.

[0042] The pump body 1, pump cover 5, and bracket 20 are all equipped with a thermal insulation structure. The thermal insulation structure includes an insulation shell, a heating inlet pipe, and a heating outlet pipe. The insulation shell is fitted over the outer walls of the pump body 1, pump cover 5, and bracket 20. A venting chamber is provided inside the insulation shell. A heating inlet and a heating outlet, both communicating with the venting chamber, are located on the insulation shell. The heating inlet pipe is connected to the heating inlet. The heating outlet pipe is connected to the heating outlet. For example, hot steam is introduced into the venting chamber through the heating inlet pipe to insulate the tar pump, which is driven by magnetic force, from transporting tar. The heating inlet pipe and the heating outlet pipe form a heating circulation loop.

[0043] The circulation channel is an internal circulation channel 15 located within the pump cover 5 and the pump body 1. The internal circulation channel 15 can guide the medium in the impeller cavity 23 to the inner cavity of the isolation sleeve 12, and return it to the impeller cavity along the hollow inner cavity of the driven shaft 6, and finally pump it out from the pump outlet, thereby carrying away the eddy current heat generated by the magnetic coupler.

[0044] In this embodiment, the inner diameter of the inner circulation channel 15 is set to 9mm to 11mm. This size is more suitable for conveying viscous media such as tar. The size of the inner hole of the inner circulation channel 15 not only increases the cooling circulation volume and can promptly remove the eddy current heat generated by the magnetic coupler, but also reduces the risk of blockage.

[0045] The middle section of the driven shaft 6 is mounted inside the pump cover 5 via a sliding bearing assembly 7 and a thrust bearing assembly 10. The magnetically driven pump also includes an elastic sleeve 9 that cushions and protects the sliding bearing assembly 7. The elastic sleeve 9 is fitted over the driven shaft 6 and is located between the sliding bearing assembly 7 and the driven shaft 6.

[0046] The magnetically driven pump also includes a front wear-resistant plate 2 and a rear wear-resistant plate 4, which are fixed inside the impeller cavity and located on the front and rear sides of the open impeller 3, respectively. The front wear-resistant plate 2 is bolted to the pump body 1. The rear wear-resistant plate 4 is bolted to the pump cover 5. Both the front wear-resistant plate 2 and the rear wear-resistant plate 4 are generally annular structures, and the surfaces adjacent to the open impeller 3 are constructed to conform to the shape of the open impeller 3.

[0047] The working principle and process of the magnetically driven pump for transporting tar of this invention are as follows:

[0048] During operation, an external motor drives the drive shaft 8 to rotate. The outer magnetic rotor 13 on the drive shaft 8 then rotates at high speed. Through magnetic lines of force penetrating the isolation sleeve 12, the outer magnetic rotor 13 drives the inner magnetic rotor 11 to rotate. The inner magnetic rotor 11 drives the driven shaft 6 to rotate synchronously, which in turn drives the open impeller 3 to rotate. The open impeller 3 is located within the impeller cavity 23 inside the pump body 1. As the driven shaft 6 rotates, the open impeller 3 transports the tar entering the pump inlet 21 and discharges it through the pump outlet 22.

[0049] During prolonged operation, the inner magnetic rotor 11 and the outer magnetic rotor 13 generate a significant amount of eddy current heat. A circulation channel connects the impeller cavity 23 with the inner cavity of the isolation sleeve 12, forming a closed-loop channel through the hollow inner cavity of the driven shaft 6. During operation, some of the medium within the impeller cavity 23 is drawn into the inner cavity of the isolation sleeve 12 through the circulation channel under the influence of pressure difference. Subsequently, this medium absorbs heat generated by the magnetic coupler within the isolation sleeve 12 and then returns to the impeller cavity 23 through the hollow inner cavity of the driven shaft 6, achieving effective heat transfer and dissipation.

[0050] Furthermore, to further improve the cleaning effect and operational stability of the magnetic drive pump for conveying tar, after the magnetic drive pump stops pumping tar, flushing fluid is supplied to the pump through the external flushing pipeline. The flushing fluid is heated by the heater 19 at the flushing fluid inlet 17, thus increasing its temperature and enhancing the tar's fluidity and flushing effect. This heated flushing fluid enters the pump and flows into the inner cavity of the isolation sleeve 12, then through the inner cavity of the driven shaft 6, or through the inner cavity of the driven shaft 6 and the internal circulation channel 15, into the impeller cavity 23, and finally flows out through the flushing fluid outlet 18. Therefore, the cleaning fluid can more effectively remove tar residue and debris accumulation from components such as the open impeller 3, pump body 1, and isolation sleeve 12.

[0051] Meanwhile, an insulation structure is also installed outside the pump. The insulation shell is wrapped around the pump body 1, pump cover 5 and bracket 20. There is a ventilation chamber inside. Hot steam is introduced into the ventilation chamber through the heating inlet pipe to form a heating circulation loop, which continuously keeps the tar in the pump warm and prevents it from solidifying. This can ensure the normal operation of the magnetically driven pump for transporting tar in low-temperature environments.

[0052] This utility model discloses a magnetically driven pump for conveying tar. It combines an open impeller 3 with a magnetic transmission system. The open impeller 3 facilitates the cleaning of tar and adhering substances, reducing maintenance costs. The isolation sleeve 12 is sealed to the pump cover 5, completely isolating the drive side from the tar and ensuring that the conveyed tar medium does not leak out. By adding external flushing, internal cleaning can be performed without disassembling the pump after shutdown, effectively preventing circulation obstruction and poor lubrication caused by tar residue or debris accumulation, thus significantly improving the pump's working efficiency and operational stability.

[0053] Furthermore, according to this application, the circulation channel is an external circulation channel 16. The external circulation channel 16 is located outside the pump body 1, unlike the internal circulation channel 15. One end of the external circulation channel 16 is connected to the pump outlet, and the other end of the external circulation channel 16 is connected to the flushing fluid inlet 17.

[0054] The external circulation channel 16 is located outside the pump body 1, enabling efficient utilization of the high-pressure liquid at the pump outlet. During the pumping of tar by the magnetic drive pump, the high-pressure liquid is introduced into the inner cavity of the isolation sleeve 12 through the external circulation channel 16, effectively removing the eddy current heat generated during magnetic coupling operation and ensuring the stable operation of the magnetic drive pump. Simultaneously, since the external circulation channel 16 is located outside the pump body 1, its design dimensions are no longer limited by the internal space of the pump body 1, allowing for a more spacious design. This significantly reduces the risk of blockage by viscous media such as tar, further improving the cooling effect and extending the service life of the equipment.

[0055] It should be noted that in the structure of the magnetic drive pump for conveying tar, either the inner circulation channel 15 or the outer circulation channel 16 can be set, or both can be set. Regardless of the setting, the magnetic drive pump for conveying tar can achieve the effect of cooling, especially when both are set, effectively ensuring the cooling effect. When the outer circulation channel 16 is set, the flushing fluid inlet 17 is connected to the circulation channel when the magnetic drive pump for conveying tar is pumping tar; and when the magnetic drive pump for conveying tar stops pumping tar and is cleaning, the flushing fluid inlet 17 is connected to the external cleaning pipeline. That is, depending on the different states of the magnetic drive pump for conveying tar, the flushing fluid inlet 17 selectively connects to the pump outlet and the external cleaning pipeline.

[0056] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and / or modifications falling within the scope of the present invention, and all changes and / or modifications made according to the embodiments of the present invention should be covered within the protection scope of the present invention.

Claims

1. A magnetic drive pump for delivering tar, characterized by include: The pump body includes an impeller cavity, a pump inlet located at the front end of the pump body and communicating with the impeller cavity, and a pump outlet located on the wall of the pump body and communicating with the impeller cavity. A flushing fluid outlet is located on the bottom wall of the pump body. A pump cover is located at the rear end of the pump body. An open impeller is located within the impeller cavity. A drive shaft and a driven shaft are included. The front end of the driven shaft passes through the pump cover and is fixedly connected to the open impeller. The driven shaft has a hollow structure. An outer magnetic rotor is fixedly connected to the drive shaft. An inner magnetic rotor is configured to cooperate with the outer magnetic rotor and is fixedly connected to the driven shaft. An isolation sleeve is barrel-shaped with its open end sealed and fixed to the pump cover. The isolation sleeve is located between the outer and inner magnetic rotors. A flushing fluid inlet is unidirectionally connected to the inner cavity of the isolation sleeve. A circulation channel connects the inner cavity of the isolation sleeve with the impeller cavity near the pump outlet.

2. The magnetic drive pump for delivering tar according to claim 1, characterized in that, A heater is provided at the inlet of the flushing fluid.

3. The magnetic drive pump for delivering tar according to claim 1, characterized in that, The drive shaft is mounted through a bearing housing, and a bracket is provided between the bearing housing and the pump cover. The bracket is cylindrical to accommodate the external magnetic rotor. Thermal insulation structures are provided on the outside of the pump body, the pump cover, and the bracket.

4. The magnetic drive pump for delivering tar according to claim 3, characterized in that, The insulation structure includes an insulation shell, a heating inlet pipe, and a heating outlet pipe. The insulation shell has a venting cavity inside, and the insulation shell has a heating inlet and a heating outlet communicating with the venting cavity. The heating inlet pipe is connected to the heating inlet, and the heating outlet pipe is connected to the heating outlet.

5. The magnetic drive pump for conveying tar according to any one of claims 1 to 4, characterized by The circulation channel is an internal circulation channel formed inside the pump cover.

6. The magnetically driven pump for conveying tar according to any one of claims 1 to 4, characterized in that, The circulation channel is an external circulation channel, one end of which is connected to the pump outlet, and the other end of which is connected to the flushing fluid inlet.

7. The magnetically driven pump for conveying tar according to any one of claims 1 to 4, characterized in that, It also includes a front wear-resistant plate and a rear wear-resistant plate, which are fixed inside the impeller cavity and are located on the front and rear sides of the open impeller, respectively.

8. The magnetic drive pump for delivering tar according to claim 7, characterized in that, The front wear-resistant plate is fixed to the pump body by bolts, and the rear wear-resistant plate is fixed to the pump cover by bolts.

9. The magnetically driven pump for conveying tar according to any one of claims 1 to 4, characterized in that, The middle section of the driven shaft is installed inside the pump cover via a sliding bearing assembly and a thrust bearing assembly.

10. The magnetic drive pump for delivering tar according to claim 9, characterized in that, It also includes an elastic sleeve, which is sleeved on the outer wall of the driven shaft and located between the sliding bearing assembly and the driven shaft.

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