Liquid sulfur pump

Abstract

The invention relates to a liquid sulfur pump. A main shaft is passed through the pump from top to bottom. A suction cover is provided at the bottom of the pump. A discharge body is provided on the upper part of the suction cover. An impeller is provided at the center of the suction cover. A guide vane is provided at the upper end of the impeller. The bottom end of the main shaft passes through the center of the impeller and the guide vane in sequence. The bottom end of the discharge body is connected with the suction cover by bolts. The top end of the discharge body is connected to a cylindrical tube by bolts. The outer circle of the guide vane is matched with the suction cover and the inner stop of the discharge body. A sliding bearing body is provided above the discharge body. A shaft liner is provided in the sliding bearing body. The sliding bearing body is connected with the discharge body and the cylindrical tube through a flange. A dynamic seal is provided above the liquid outlet pipe. Gas is provided between the dynamic seal and the bottom plate. An air cavity is formed in the pump between the auxiliary impeller and the bottom plate to form an auxiliary impeller dynamic seal. The air cavity serves as an isolation cavity to reduce the heat conduction from the steam insulation area to the bearing cooling area, thereby preventing the heat from being transmitted and causing the temperature at the bearing to be too high.

Description

Technical Field

[0001] The present invention relates to a liquid sulfur pump, which belongs to a high-temperature jacketed submersible pump. The overall structure is a vertical centrifugal pump with a single-stage or multi-stage, single-suction, open or closed impeller. The pump is suitable for conveying high-temperature, high-melting-point, easily solidified dangerous media such as phthalic anhydride and liquid sulfur, with a maximum temperature of 260°C. Background Art

[0002] Under normal working conditions, sulfur exists in the pump in liquid form and is transported, and the temperature condition is required to be between 140 and 150 degrees Celsius;

[0003] In winter, in low temperature environments or shutdown states, the sulfur in the pump turns into solid crystals at temperatures below 40 degrees. After solidification, the sulfur cannot be transported in the pump, causing the pump to fail to work. Therefore, the pump needs to be kept under high temperature conditions to maintain normal operation.

[0004] Therefore, the present application is about how to keep the pump warm during operation and how to solve the problem of sulfur solidification after the pump is stopped and cooled, which is a technical problem that needs to be solved urgently.

[0005] In the traditional liquid sulfur pump structure, the pumping medium is discharged from the pump and led to the bottom plate through a separate liquid outlet pipe. There is no flow and flushing between the sliding bearings under the liquid medium. The flushing of the sliding bearings must be completed by the flushing pipe led from the pump outlet. The flushing pipe also needs to be insulated. Under certain temperature and insulation time, the sulfur in the flushing pipe must be melted before flushing can be performed. When starting the car after maintenance or parking, even if you can easily turn the car, you cannot determine whether the flushing pipe is unobstructed. If the insulation time is not enough, the sliding bearing will be dry-grinded and damaged. Summary of the invention

[0006] A liquid sulfur pump designed in the present application solves the flushing problem of sliding bearings. The pump can be started immediately as long as it can be easily cranked. A dynamic sealing structure is arranged at the pump outlet, and the sliding bearing seat can be kept warm by steam. The sliding bearing is self-flushing, and the underwater depth can reach 10m.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a liquid sulfur pump, a main shaft is passed through the inside of the pump from top to bottom, a suction cover is provided at the bottom of the pump, a discharge body is provided on the upper part of the suction cover, an impeller is provided at the center of the suction cover, a guide vane is provided at the upper end of the impeller, and the bottom end of the main shaft passes through the center of the impeller and the guide vane in sequence; the bottom end of the discharge body is connected to the suction cover by bolts, the top end of the discharge body is connected to the cylindrical tube by bolts, the outer circle of the guide vane is matched with the inner stop of the suction cover and the discharge body, a sliding bearing body is provided above the discharge body, a shaft liner is provided in the sliding bearing body, and the sliding bearing body is connected to the discharge body and the cylindrical tube through a flange;

[0008] A bottom plate is provided in the middle of the pump, a bearing frame is provided on the bottom plate, a connecting seat is provided at the bottom end of the bearing frame, the connecting seat is connected to the bottom plate by bolts, and the connecting seat is connected to the upper cylindrical tube by bolts; a sealing box is provided in the bearing frame located above the bottom plate, and the bottom end of the sealing box is connected to the connecting seat by bolts; a bearing chamber is provided on the bearing frame located above the sealing box, a bearing component is provided in the bearing chamber, a motor frame is provided above the bearing chamber, and a coupling and a motor are installed on the motor frame;

[0009] The outlet section of the pump located below the bottom plate is provided with a liquid outlet pipe, which is an L-shaped structure, one end of which is connected to the inside of the pump and the other end extends to the upper end of the bottom plate; the pump is connected to an auxiliary impeller at a position higher than the root of the liquid outlet pipe by bolts.

[0010] Furthermore, a cooling water pipe is provided at both ends of the upper end of the bearing frame near the bearing component, and a cooling water outlet is provided on the two cooling water pipes respectively. The two cooling water outlets are located on both sides of the bearing frame at a high and low height.

[0011] Furthermore, a bearing cover is arranged at the upper end of the bearing body in the bearing chamber, the bearing cover is connected to the bearing body by bolts, an oil nipple is opened at the upper end of the bearing cover, the lower part of the bearing body is supported by a bearing frame, a bearing sleeve is arranged outside the pump main shaft corresponding to the inner wall of the bearing body, and a bearing is arranged between the inner wall of the bearing body and the outer wall of the bearing sleeve; a lower flange is installed at the lower end of the bearing frame, a sealing box body is arranged on the lower flange of the bearing frame, a shaft sleeve is arranged on the outer wall of the pump main shaft corresponding to the inner side of the sealing box body, and a packing is arranged between the sealing box body and the shaft sleeve; the sealing box body adopts a maintenance-free packing structure and is connected to a cooling water inlet pipe and a cooling water outlet pipe through pipelines.

[0012] Furthermore, an air cavity is formed in the upper cylindrical tube between the auxiliary impeller and the bottom plate; the pump forms a dynamic seal through the auxiliary impeller; the gas is isolated by the auxiliary impeller seal, and a dynamic seal structure is adopted. The pumped medium is discharged from a separate liquid outlet pipe, and the shaft seal at the upper bottom plate does not seal the pumped high-pressure medium, but only seals the volatile gas.

[0013] Furthermore, an annular cavity is provided below the auxiliary impeller, the pump main shaft passes through the center of the annular cavity, the lower part of the inner wall of the annular cavity is connected to the sliding bearing body, the liquid outlet pipe is connected to the outer wall of the annular cavity on the side of the outlet section where the liquid outlet pipe is located, and a first leakage hole is provided in the lower part of the annular cavity away from the liquid outlet pipe. The first leakage hole passes through the inner wall and the outer wall of the annular cavity and is used for the leaked medium to flow back to the sulfur tank; the lower end of the upper cylindrical tube is provided with a second leakage hole.

[0014] The outlet section comprises: an annular cavity, upper and lower flanges of the annular cavity, a first leakage hole and a liquid outlet pipe head.

[0015] In the present application, in order to prevent the medium in the pump from solidifying and crystallizing on the inner wall of the pump, a steam pipe inlet is provided at the upper position of the liquid outlet pipe, a first steam pipe is connected between the lower end of the liquid outlet pipe and the upper part of the air cavity close to the direction of the liquid outlet pipe, a second steam pipe is connected to the outer upper end of the auxiliary impeller cavity on the side of the air cavity away from the direction of the liquid outlet pipe, a third steam pipe is provided between the upper and lower parts of the cavity of the auxiliary impeller close to the direction of the liquid outlet pipe and they are connected, a fourth steam pipe is provided between the lower part of the auxiliary impeller cavity in the same direction as the second steam pipe and the sliding bearing body, a steam outlet pipe is provided from the sliding bearing body in the same direction as the third steam pipe to the top of the liquid outlet pipe, and the top of the steam outlet pipe passes through the bottom plate and extends to the height position of the top of the liquid outlet pipe; from the steam pipe inlet - steam inlet pipe - passing through the air cavity of the pump - auxiliary impeller - sliding bearing body - steam outlet pipe - steam outlet, the whole process realizes the steam insulation of the pump;

[0016] The function of the air cavity is that the steam passing through the lower part of the dynamic seal needs a higher temperature, while the bearing room above the bottom plate of the upper part of the air cavity needs a lower temperature. The air cavity acts as an isolation cavity to reduce the heat conduction from the steam insulation area to the bearing cooling area, thereby preventing the heat from being transferred up and causing the temperature at the bearing to be too high.

[0017] Furthermore, in the above steam insulation structure, the sliding bearing at the front end of the power seal is steam-insulated, and the sliding bearing can achieve self-flushing;

[0018] Furthermore, the dynamic seal form of the auxiliary impeller can adopt a 1-stage or 2-stage auxiliary impeller structure according to the pump outlet pressure;

[0019] Furthermore, the impeller and guide vane adopt advanced design methods to simulate and correct the hydraulic model, which is highly efficient and energy-saving, with small reaction pulses at the blade outlet and guide vane, small radial force, and increased service life of the liquid sliding bearing; the impeller can be designed into 2 or more stages according to needs;

[0020] Furthermore, the liquid outlet pipe adopts a free telescopic structure to prevent the thermal deformation of different parts from causing deformation of the pump body and affecting its use.

[0021] Using the above technical solution, the working process and principle of the present invention are:

[0022] During normal operation, sulfur is transported in the pump in a high-temperature liquid state, with the temperature controlled at 140-150 degrees Celsius;

[0023] When the machine needs to be restarted after shutdown, the main shaft cannot rotate before starting because the sulfur is in a solidified state; the solidified sulfur needs to be melted by passing steam; the steam is introduced through the inlet of the steam pipe, reaches the air cavity through the first steam pipe, passes through the air cavity through the second steam pipe to enter the insulation cavity of the auxiliary impeller, is led out from the third steam pipe of the auxiliary impeller and returns, and then enters the sliding bearing body through the fourth steam pipe, is led out to the steam outlet pipe after passing through the sliding bearing, and is discharged from the insulation steam outlet; in this process, the entire steam pipeline can melt the solidified sulfur in the pump into a liquid state, and can be in a normal conveying state, at this time, the motor main shaft can be driven to rotate, and the sulfur flows upward along the main shaft in the pump through the rotation of the impeller of the pump part. At this time, the medium provides an upward force through the impeller; the medium exerts downward pressure on the medium through the action of the upper auxiliary impeller, realizes sealing and prevents the medium from entering the air cavity above the auxiliary impeller; thereby reducing the heat conduction from the steam insulation area to the bearing cooling area, and achieving an isolation effect;

[0024] In the above process, when the pump works normally, most of the sulfur is discharged from the liquid outlet pipe through the main flow channel, and the remaining sulfur flows upward through the gap of the sliding bearing and enters the space formed by the inner wall of the annular cavity. After entering, part of the sulfur flows back to the sulfur tank through the first leakage hole, the sulfur pressure is reduced, and the remaining sulfur enters the cavity on the upper part of the sliding bearing, and is sealed in the cavity below the auxiliary impeller through the dynamic sealing action of the auxiliary impeller; if the auxiliary impeller is not completely sealed, at this time, a small amount of remaining sulfur leaks through the auxiliary impeller seal to the upper cylindrical tube, and flows back to the sulfur tank through the second leakage hole of the upper cylindrical tube.

[0025] The beneficial effects of the present invention are:

[0026] A dynamic seal is set above the liquid outlet pipe. There is gas between the dynamic seal and the bottom plate. An air cavity is formed in the pump between the auxiliary impeller and the bottom plate, which constitutes the auxiliary impeller dynamic seal. The air cavity serves as an isolation cavity to reduce the heat conduction from the steam insulation area to the bearing cooling area, preventing the heat from being uploaded and causing the bearing temperature to be too high. The pump seal adopts a maintenance-free packing structure and can be cooled. The submerged part of the rotor is supported by a sliding bearing. The sliding bearing seat can be insulated by steam, and the sliding bearing is self-flushing. The submerged depth can reach 10m. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the overall structure diagram of the present invention.

[0028] In the figure, 1, cylindrical tube, 1.1, upper cylindrical tube, 2, main shaft, 3, suction cover, 4, discharge body, 5, impeller, 6, guide vane, 7-1, sliding bearing body, 7-2, bushing, 7-3, sleeve, 8, bottom plate, 9, sealing box, 10, bearing chamber, 10-1, bearing body, 10-2, bearing pressure cover, 10-3, bearing frame, 10-4, bearing sleeve, 10-5, bearing, 11, cooling water outlet, 12, motor, 13, liquid outlet pipe, 13.1, liquid outlet pipe head, 14, seal Box cooling water inlet pipe, 15, sealed box cooling water outlet pipe, 16, auxiliary impeller, 16.1, auxiliary impeller cavity, 17, air cavity, 18, annular cavity, 18.1, annular cavity inner wall, 18.2, annular cavity outer wall, 19, first leakage hole, 20, steam pipe inlet, 21, first steam pipe, 22, second steam pipe, 23, third steam pipe, 24, fourth steam pipe, 25, steam outlet pipe, 26, steam outlet, 27, motor frame, 28, coupling, 29, second leakage hole. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings.

[0030] like Figure 1 As shown, a liquid sulfur pump is provided, wherein a main shaft 2 is passed through the inside of the pump from top to bottom, a suction cover 3 is provided at the bottom of the pump, a discharge body 4 is provided on the upper part of the suction cover 3, an impeller 5 is provided at the center of the suction cover 3, a guide vane 6 is provided at the upper end of the impeller 5, and the bottom end of the main shaft 2 passes through the centers of the impeller 5 and the guide vane 6 in sequence; the bottom end of the discharge body 4 is connected to the suction cover 3 by bolts, the top end of the discharge body 4 is connected to the cylindrical tube 1 by bolts, the outer circle of the guide vane 6 is matched with the inner stop of the suction cover 3 and the discharge body 4, a sliding bearing body 7-1 is provided above the discharge body 4, a shaft liner 7-2 is provided in the sliding bearing body 7-1, and the sliding bearing body 7-1 is connected to the discharge body 4 and the cylindrical tube 1 through a flange;

[0031] A base plate 8 is provided in the middle of the pump, a bearing frame 10-3 is provided on the base plate 8, a connecting seat is provided at the bottom end of the bearing frame 10-3, the connecting seat is connected to the base plate 8 by bolts, and the connecting seat is connected to the upper cylindrical tube 1.1 by bolts; a sealing box body 9 is provided in the bearing frame 10-3 located above the base plate 8, and the bottom end of the sealing box body 9 is connected to the connecting seat by bolts; a bearing chamber 10 is provided on the bearing frame 10-3 located above the sealing box body 9, a bearing component is provided in the bearing chamber 10, and a motor frame 27 is provided above the bearing chamber 10, and a coupling 28 and a motor 12 are installed on the motor frame 27;

[0032] The outlet section of the pump located below the base plate 8 is provided with a liquid outlet pipe 13, which is an L-shaped structure. One end of the liquid outlet pipe 13 is connected to the inside of the pump, and the other end extends to the upper end of the base plate 8; the pump is connected to an auxiliary impeller 16 at a position higher than the root of the liquid outlet pipe 13 by bolts.

[0033] Furthermore, a cooling water pipe is provided at both ends of the upper end of the bearing frame 10-3 near the bearing component, and a cooling water outlet 11 is provided on the two cooling water pipes respectively. The two cooling water outlets 11 are located on both sides of the bearing frame 10-3 at a high and low height.

[0034] Furthermore, a bearing cover 10-2 is arranged at the upper end of the bearing body 10-1 in the bearing chamber 10, and the bearing cover 10-2 is connected to the bearing body 10-1 by bolts. An oil nozzle is opened at the upper end of the bearing cover 10-2, and the lower part of the bearing body 10-1 is supported by a bearing frame 10-3. A bearing sleeve 10-1 is arranged outside the pump main shaft 2 corresponding to the inner wall of the bearing body 10-1, and a bearing 10-5 is arranged between the inner wall of the bearing body 10-1 and the outer wall of the bearing sleeve 10-4; a lower flange is installed at the lower end of the bearing frame 10-3, and a sealing box body 9 is arranged on the lower flange of the bearing frame 10-3, and a shaft sleeve 7-3 is arranged on the outer wall of the pump main shaft 2 corresponding to the inner side of the sealing box body 9, and a packing is arranged between the sealing box body 9 and the shaft sleeve 7-3; the sealing box body 9 adopts a maintenance-free packing structure and is connected to a cooling water inlet pipe 14 and a cooling water outlet pipe 15 through pipelines.

[0035] Furthermore, an air cavity 17 is formed in the upper cylindrical tube 1.1 between the auxiliary impeller 16 and the bottom plate 8; the pump adopts a dynamic sealing structure, forms a dynamic seal through the auxiliary impeller, and forms an isolation cavity above the auxiliary impeller; the pumped medium is discharged from a separate liquid outlet pipe 13, and the shaft seal at the upper bottom plate 8 does not seal the pumped high-pressure medium, but only seals the volatile gas.

[0036] Furthermore, an annular cavity 18 is provided below the auxiliary impeller 16, the pump main shaft 2 passes through the center of the annular cavity 18, the lower part of the inner wall 18.1 of the annular cavity is connected to the sliding bearing body 7-1, the liquid outlet pipe 13 is connected to the outer wall 18.2 of the annular cavity on the side of the outlet section where it is located, and a first leakage hole 19 is provided at the lower part of the annular cavity 18 away from the liquid outlet pipe 13. The first leakage hole 19 passes through the inner wall 18.1 and the outer wall 18.2 of the annular cavity and is used for the leaked medium to flow back to the sulfur tank; the lower end of the upper cylindrical tube 1.1 is provided with a second leakage hole 29.

[0037] The outlet section comprises: an annular cavity 18, upper and lower flanges of the annular cavity, a first leakage hole 19 and a liquid outlet pipe head 13.1.

[0038] In the present application, in order to prevent the medium in the pump from solidifying and crystallizing on the inner wall of the pump, a steam pipe inlet 20 is provided at the upper position of the liquid outlet pipe 13, a first steam pipe 21 is connected between the lower end of the liquid outlet pipe 13 and the upper part of the air cavity 17 close to the liquid outlet pipe 13, a second steam pipe 22 is connected to the outer upper end of the auxiliary impeller cavity 16.1 on the side of the air cavity 17 away from the liquid outlet pipe 13, and a third steam pipe 23 is provided between the upper and lower parts of the cavity 16.1 of the auxiliary impeller 16 close to the liquid outlet pipe 13 and is connected to the second steam pipe 22. A fourth steam pipe 24 is provided between the lower part of the auxiliary impeller cavity 16.1 in the same direction as the third steam pipe 23 and the sliding bearing body 7-1, and a steam outlet pipe 25 is provided from the sliding bearing body 7-1 to the top of the liquid outlet pipe 13 in the same direction as the third steam pipe 23. The top of the steam outlet pipe 25 passes through the bottom plate 8 and extends to the height position of the top of the liquid outlet pipe 13; from the steam pipe inlet 20 - steam inlet pipe - through the air cavity 17 of the pump - auxiliary impeller 16 - sliding bearing body 7-1 - steam outlet pipe 25 - steam outlet 26, the whole process realizes the steam insulation of the pump;

[0039] The function of the air cavity 17 is that the steam passing through the lower part of the dynamic seal needs a higher temperature, while the bearing chamber 10 above the bottom plate 8 of the upper part of the air cavity 17 needs a lower temperature. The air cavity 17 acts as an isolation cavity to prevent the heat conduction from the steam insulation area to the bearing cooling area from being reduced, thereby preventing the heat from being transferred up and causing the temperature at the bearing to be too high.

[0040] The flow component of the present invention adopts a liquid reflux design when the vehicle is stopped, so as to ensure that the sulfur liquid flows back into the tank when the vehicle is stopped, and prevents the sulfur liquid from accumulating in the pump, and prevents the pump from solidifying at room temperature after being taken out for maintenance, which increases the difficulty of disassembly and causes maintenance difficulties.

[0041] At the lower end of the pump (immersed in the liquid), axial outflow is adopted, and the sliding bearing is lubricated by the medium. At the outlet section, a dynamic sealing structure is adopted, and the pumped medium is discharged from a separate liquid outlet pipe 13. The shaft seal at the upper end bottom plate 8 does not seal the pumped high-pressure medium, but only seals the volatile gas.

[0042] During normal operation, sulfur is transported in the pump in a high-temperature liquid state, with the temperature controlled at 140-150 degrees Celsius;

[0043] When the machine needs to be restarted after shutdown, the main shaft 2 cannot rotate before restarting because the sulfur is in a solidified state; the solidified sulfur needs to be melted by passing steam; the steam is introduced through the steam pipe inlet 20, reaches the air cavity 17 through the first steam pipe 21, passes through the air cavity 17 through the second steam pipe 22 and enters the insulation cavity of the auxiliary impeller 16, is led out from the third steam pipe 23 of the auxiliary impeller 16 and returns, then enters the sliding bearing body 7-1 through the fourth steam pipe 24, passes through the sliding bearing, is led out to the steam outlet pipe 25, and then exits from the insulation steam outlet The sulfur is discharged from the outlet 26; in this process, the entire steam pipeline can melt the solidified sulfur in the pump into a liquid state, and can be transported normally. At this time, the motor main shaft 2 can be driven to rotate, and the sulfur flows upward along the main shaft 2 in the pump through the rotation of the impeller 5 of the pump. At this time, the medium is provided with an upward force by the impeller 5; the medium is pressed downward by the upper auxiliary impeller 16, so as to achieve sealing and prevent the medium from entering the air cavity 17 above the auxiliary impeller 16; thereby reducing the heat conduction from the steam insulation area to the bearing cooling area, and achieving an isolation effect;

[0044] In the above process, when the pump works normally, most of the sulfur is discharged from the liquid outlet pipe 13 through the main flow channel, and the remaining sulfur flows upward through the gap of the sliding bearing and enters the space formed by the inner wall 18.1 of the annular cavity. After entering, a part of the sulfur flows back to the sulfur tank through the first leakage hole 19, the sulfur pressure is reduced, and the remaining sulfur enters the cavity above the sliding bearing, and the sulfur is sealed in the cavity below the auxiliary impeller 16 through the dynamic sealing action of the auxiliary impeller 16; if the auxiliary impeller 16 is not completely sealed, at this time, a small amount of remaining sulfur leaks through the seal of the auxiliary impeller 16 to the upper cylindrical tube 1.1, and flows back to the sulfur tank through the second leakage hole 29 of the upper cylindrical tube 1.1.

[0045] The liquid sulfur pump of the present invention is a high-temperature jacketed submerged pump, and its overall structure is a vertical centrifugal pump with a single-stage or multi-stage, single-suction, open or closed impeller.

Claims

1. Liquid sulfur pump, characterized in that: A main shaft is passed through the pump from top to bottom, a suction cover is provided at the bottom of the pump, a discharge body is provided on the upper part of the suction cover, an impeller is provided at the center of the suction cover, a guide vane is provided at the upper end of the impeller, and the bottom end of the main shaft passes through the center of the impeller and the guide vane in sequence; the bottom end of the discharge body is connected to the suction cover by bolts, the top end of the discharge body is connected to the cylindrical tube by bolts, the outer circle of the guide vane is matched with the inner stop of the suction cover and the discharge body, a sliding bearing body is provided above the discharge body, a shaft liner is provided in the sliding bearing body, and the sliding bearing body is connected to the discharge body and the cylindrical tube through a flange; A bottom plate is provided in the middle of the pump, a bearing frame is provided on the bottom plate, a connecting seat is provided at the bottom end of the bearing frame, the connecting seat is connected to the bottom plate by bolts, and the connecting seat is connected to the upper cylindrical tube by bolts; The outlet section of the pump located below the bottom plate is provided with a liquid outlet pipe, which is an L-shaped structure, one end of which is connected to the inside of the pump, and the other end extends to the upper end of the bottom plate; the position of the pump above the root of the liquid outlet pipe is connected with an auxiliary impeller by bolts; A cooling water pipe is provided at both ends of the upper end of the bearing frame near the bearing component, and cooling water outlets are provided on the two cooling water pipes respectively. The two cooling water outlets are arranged at two sides of the bearing frame, one high and one low. A bearing gland is arranged at the upper end of the bearing body in the bearing chamber, and an oil nozzle is opened at the upper end of the bearing gland. An air cavity is formed in the upper cylindrical tube between the auxiliary impeller and the bottom plate; the pump forms a dynamic seal through the auxiliary impeller; An annular cavity is also provided below the auxiliary impeller, the main shaft of the pump passes through the center of the annular cavity, the lower part of the inner wall of the annular cavity is connected to the sliding bearing body, the liquid outlet pipe is connected to the outer wall of the annular cavity on the side of the outlet section where it is located, and a first leakage hole is provided at the lower part of the annular cavity away from the liquid outlet pipe; a second leakage hole is provided at the lower end of the upper cylindrical tube; A steam pipe inlet is provided at the upper position of the liquid outlet pipe, a first steam pipe is connected between the lower end of the liquid outlet pipe and the upper part of the air cavity close to the direction of the liquid outlet pipe, a second steam pipe is connected to the outer upper end of the auxiliary impeller cavity on the side of the air cavity away from the direction of the liquid outlet pipe, a third steam pipe is provided between the upper and lower parts of the cavity of the auxiliary impeller close to the direction of the liquid outlet pipe and they are connected, a fourth steam pipe is provided between the lower part of the auxiliary impeller cavity in the same direction as the second steam pipe and the sliding bearing body, a steam outlet pipe is provided from the sliding bearing body in the same direction as the third steam pipe to the top end of the liquid outlet pipe, and the top end of the steam outlet pipe passes through the bottom plate and extends to the height position of the top of the liquid outlet pipe.

2. The liquid sulfur pump according to claim 1, characterized in that: The dynamic seal form of the auxiliary impeller adopts a 1-stage or 2-stage auxiliary impeller structure according to the pump outlet pressure.

3. The liquid sulfur pump according to claim 1, characterized in that: The impeller is designed into two stages according to needs; the impeller part is designed into a local dry shaft structure.

4. The liquid sulfur pump according to any one of claims 1 to 3, characterized in that: During normal operation, sulfur is transported in the pump in a high-temperature liquid state, with the temperature controlled at 140-150 degrees Celsius; When the machine needs to be restarted after shutdown, the main shaft cannot rotate because the sulfur is in a solidified state before starting up; the solidified sulfur needs to be melted by heat-insulating steam; the steam is introduced through the steam pipe inlet, reaches the air cavity through the first steam pipe, passes through the air cavity through the second steam pipe to the auxiliary impeller, is led out from the third steam pipe of the auxiliary impeller and returns, and then enters the sliding bearing body through the fourth steam pipe, is led out to the steam outlet pipe after passing through the sliding bearing, and is discharged from the heat-insulating steam outlet; in this process, the entire steam pipeline can realize the melting of the solidified sulfur in the pump into a liquid state, and can be in a normal conveying state, at this time, the motor main shaft can be driven to rotate, and the sulfur flows upward along the main shaft in the pump through the rotation of the impeller of the pump part. At this time, the medium provides an upward force through the impeller; The medium exerts downward pressure on the medium through the action of the upper auxiliary impeller, thereby achieving sealing and preventing the medium from entering the air cavity above the auxiliary impeller.

5. The liquid sulfur pump according to claim 4, characterized in that: In the above process, when the pump works normally, most of the sulfur is discharged from the liquid outlet pipe through the main flow channel, and the remaining sulfur flows upward through the gap of the sliding bearing and enters the space formed by the inner wall of the annular cavity. After entering, part of the sulfur flows back to the sulfur tank through the first leakage hole, the sulfur pressure is reduced, and the remaining sulfur enters the cavity on the upper part of the sliding bearing, and is sealed in the cavity below the auxiliary impeller through the dynamic sealing action of the auxiliary impeller; if the auxiliary impeller is not completely sealed, at this time, a small amount of remaining sulfur leaks through the auxiliary impeller seal to the upper cylindrical tube, and flows back to the sulfur tank through the second leakage hole of the upper cylindrical tube.

6. The liquid sulfur pump according to claim 1, characterized in that: A sealing box is arranged in the bearing frame located above the bottom plate, and the bottom end of the sealing box is connected to the connecting seat by bolts; a bearing chamber is arranged on the bearing frame above the sealing box, and a bearing component is arranged in the bearing chamber; a motor frame is arranged above the bearing chamber, and a motor is installed on the motor frame; The bearing gland is connected to the bearing body by bolts, the lower part of the bearing body is supported by the bearing frame, a bearing sleeve is provided outside the pump main shaft corresponding to the inner wall of the bearing body, and a bearing is provided between the inner wall of the bearing body and the outer wall of the bearing sleeve; a lower flange is installed at the lower end of the bearing frame, a sealing box is provided on the lower flange of the bearing frame, a shaft sleeve is provided on the outer wall of the pump main shaft corresponding to the inner side of the sealing box, and a packing is provided between the sealing box and the shaft sleeve; the sealing box adopts a maintenance-free packing structure and is connected to a cooling water inlet pipe and a cooling water outlet pipe through pipelines; the first leakage hole passes through the inner wall and the outer wall of the annular cavity, and is used for the leakage medium to flow back to the sulfur tank.

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