Dredge pump shaft seal service device

Abstract

The invention discloses a dredge pump shaft seal service device. The dredge pump shaft seal service device comprises a water inlet pipeline and a water outlet pipeline, the cyclone purification device is connected in series to the downstream of the water inlet pipeline; the downstream of the cyclone purification device is connected in series with a variable-frequency booster pump A one-way valve is arranged between the cyclone purification device and the variable frequency booster pump; the downstream of the variable-frequency booster pump is connected with a dredge pump shaft seal assembly through two pipelines, and the two pipelines are each provided with an electric pressure regulating valve and a flow sensor in sequence; the dredge pump shaft seal assembly is connected to a dredge pump suction port through two water outlet pipelines; the two water outlet pipes are respectively and sequentially provided with a pressure sensor and a pressure speed regulating valve; the PID controller performs closed-loop control on the opening degree of the electric control valve and the flow of the speed regulating valve; and the residual water discharging pipe is connected with the low point of the cyclone purification device pipeline. Sealing water purification and graded pressure relief are achieved, abrasion of the sealing assembly is reduced, and the service life is prolonged.

Description

Technical Field

[0001] This invention belongs to the technical field of engineering vessel dredging equipment, specifically a mud pump shaft seal service device. Background Technology

[0002] Mud pumps are core dredging equipment on engineering vessels, and their operational stability directly determines construction efficiency. In actual dredging operations, mud pump shaft seal failures occur frequently, with service lives varying greatly, ranging from less than a month to less than a year. Frequent downtime for maintenance severely disrupts the construction process and has become a key bottleneck restricting operational efficiency. Analysis revealed two main causes of shaft seal failure: First, the sealing water contained silt, and the high-speed flowing silt caused continuous wear on the sealing components, leading to decreased sealing performance and increased risk of leakage. Second, the low back pressure of the shaft seal water easily resulted in insufficient cooling water, which could not form effective cooling and lubrication protection (such as in mud blowing conditions), further aggravating the wear of the seal components. In existing technologies, traditional bushings employ a spiral groove seal design. While introducing cooling water through spiral grooves machined on the bushing surface extends the heat exchange path, it has significant drawbacks: Firstly, the uneven surface of the spiral grooves in traditional bushings leads to uneven contact pressure and frictional resistance during relative movement of the sealing surfaces, accelerating wear of the second seal. Secondly, the pressure is highly concentrated on the first seal, preventing the second and third chambers from forming effective pressure resistance. Under continuous high pressure, the first seal excessively contacts the rotating shaft, generating excessive contact stress and frictional resistance, exacerbating sealing system failure. Furthermore, existing sealing water only undergoes treatment by a sand separator, inevitably carrying sediment, failing to fundamentally prevent sediment from eroding and wearing the sealing components. Additionally, traditional dual-inlet / outlet water pipes can only provide a single working pressure, causing the sealing components to endure high pressure for extended periods, resulting in severe frictional wear. Therefore, there is an urgent need for a mud pump shaft seal service device that can fundamentally solve the problems of mud and sand wear and high pressure loss, so as to improve the service life of the shaft seal and the stability of equipment operation. Summary of the Invention

[0003] To address the aforementioned problems in the existing technology, this invention provides a mud pump shaft seal service device that achieves sealed water purification, graded pressure relief, reduces wear on sealing components, and extends service life.

[0004] The technical solution to achieve the above objectives is: A mud pump shaft seal service device includes: a variable frequency booster pump, two sets of electric return water pressure regulating valves, a PID controller, a hydrocyclone purification device, and a pipeline system; the pipeline system includes one inlet pipe, two outlet pipes, and a residual water drain pipe; in, The water inlet pipe is used to connect to the branch pipe of the discharge water pump at the shaft end sealing water pump; The hydrocyclone purification device is connected in series downstream of the water inlet pipe; The variable frequency booster pump is connected in series downstream of the cyclone purifier; A one-way valve is provided between the cyclone purifier and the variable frequency booster pump; The downstream of the variable frequency booster pump is connected to the mud pump shaft seal assembly through two pipelines. Each of the two pipelines is equipped with an electric pressure regulating valve and a flow sensor. The electric pressure regulating valve includes a first electric pressure regulating valve and a second electric pressure regulating valve. The mud pump shaft seal assembly is connected to the mud pump suction port through two water outlet pipes; Each of the two water outlet pipes is equipped with a pressure sensor and a pressure speed regulating valve in sequence. The PID controller uses a closed-loop control to adjust the opening degree of the electronically controlled valve and the flow rate of the speed regulating valve. The residual water drain pipe is connected to the lowest point of the hydrocyclone purification device pipeline.

[0005] Preferably, the hydrocyclone purification device is used to separate solid mud and sand impurities from the sealing water, and the purified water is used as shaft seal water and detected as the first-level pressure P1 input.

[0006] Preferably, the variable frequency booster pump is used to ensure stable output of the secondary pressure P2 and the tertiary pressure P3.

[0007] Preferably, the first electric pressure regulating valve is used to dynamically regulate the pressure of the shaft end sealing water pump by combining with the PID controller, and output a secondary pressure P2.

[0008] Preferably, the second electric pressure regulating valve is used to achieve secondary pressure relief by combining with the PID controller, and is used to output a tertiary pressure P3 to the mud pump shaft seal assembly. The flow sensor is used to monitor the sealing water flow rate and feed it back to the PID controller.

[0009] Preferably, the pressure sensor is used to monitor the return water pressure, and the pressure regulating valve is used to stabilize the return water flow rate.

[0010] Preferably, the residual water pipe is used to discharge residual mud and solid particles from the sealed water.

[0011] Preferably, the device constructs a graded pressure system of "primary pressure P1, secondary pressure P2, and tertiary pressure P3". in, The primary pressure P1 is the pressure of the shaft end seal water pump, which matches the working conditions of the mud pump. The secondary pressure P2 is calculated and determined according to P1×2 / 3, and the downstream pressure is dynamically adjusted by the PID controller in conjunction with the first electric pressure regulating valve. The third-level pressure P3 is calculated and determined according to P1×1 / 3, and secondary pressure relief is achieved by the PID controller in conjunction with the second electric pressure regulating valve. After staged pressure relief, the shaft seal assembly actually withstands a relative pressure of level three, P3. The first-level pressure P1 is set to 9 bar under sludge blowing conditions, corresponding to a second-level pressure P2 of 6 bar and a third-level pressure P3 of 3 bar.

[0012] Preferably, it also includes: pressure display units at each level, wherein the pressure display units respectively display the real-time values ​​of the first-level pressure P1, the second-level pressure P2, and the third-level pressure P3.

[0013] Preferably, the output end of the hydrocyclone purification device and the shaft seal lubrication and cooling channel of the mud pump shaft seal assembly form a unidirectional flow channel.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention constructs a graded pressure system of "first-level pressure - second-level pressure relief - third-level pressure relief", combined with PID closed-loop control and variable frequency booster pump, to reduce the actual pressure borne by the sealing component from the traditional first-level working pressure to P1×1 / 3, reduce the stress intensity by 67%, significantly reduce the friction loss caused by high pressure, and solve the problem of high pressure wear of traditional shaft seals from the root. This invention adds a hydrocyclone purification device to efficiently separate mud and sand particles with a diameter >0.1mm in the sealing water based on the principle of centrifugal separation. This ensures that the cooling and lubricating water delivered to the shaft seal is free of abrasive impurities, avoids continuous scouring and wear of the sealing components by mud and sand, and significantly extends the service life of the sealing components. The device of this invention integrates auxiliary structures such as pressure display, residual water discharge pipe, and unidirectional flow channel to realize functions such as real-time pressure monitoring, discharge of residual impurities, and prevention of backflow, thereby improving the stability of equipment operation and ease of maintenance. It eliminates the traditional shaft sleeve spiral groove design, which simplifies the structure and reduces processing costs. Moreover, the graded pressure adjustment is adapted to different mud pump conditions (such as mud blowing operations), making it highly versatile and with broad application prospects. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of a mud pump shaft seal service device according to the present invention.

[0016] In the diagram: 1. Inlet pipe; 2. Hydrocyclone purification device; 3. Check valve; 4. Variable frequency booster pump; 5. Mud pump shaft seal assembly; 61. First electric pressure regulating valve; 62. Second electric pressure regulating valve; 7. Flow sensor; 8. Outlet pipe; 9. Mud pump suction port; 10. Pressure sensor; 11. Pressure speed regulating valve; 12. PID controller; 13. Residual water drain pipe; 14. Pressure display unit. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1 As shown, a mud pump shaft seal service device includes: a hydrocyclone purification device 2, a one-way valve 3, a variable frequency booster pump 4, an electric pressure regulating valve (a first electric pressure regulating valve 61 and a second electric pressure regulating valve 62), a PID controller 12, a pipeline system, and pressure display units at various levels 14; the pipeline system includes one inlet pipe 1, two outlet pipes 8, and a residual water drain pipe 13. in, The inlet pipe 1 is used to connect to the branch pipe of the discharge water pipe of the shaft end seal water pump; the hydrocyclone purification device 2 is connected in series downstream of the inlet pipe 1; a one-way valve 3 is connected in series downstream of the hydrocyclone purification device 2; a variable frequency booster pump 4 is installed after the one-way valve 3; the downstream of the variable frequency booster pump 4 is connected to the mud pump shaft seal assembly 5 through two pipes, and each of the two pipes is equipped with an electric pressure regulating valve (i.e., the first electric pressure regulating valve 61 and the second electric pressure regulating valve 62) and a flow sensor 7; the mud pump shaft seal assembly 5 is connected to the mud pump suction port 9 through two outlet pipes 8; a pressure sensor 10 and a pressure speed regulating valve 11 are installed in sequence on the two outlet pipes 8; the PID controller 12 controls the opening degree of the electric control valve and the flow rate of the speed regulating valve in a closed loop; the residual water pipe 13 is connected to the low point of the hydrocyclone purification device 2 pipeline; the pressure display unit 14 displays the real-time values ​​of the first-level pressure P1, the second-level pressure P2 (P1×2 / 3), and the third-level pressure P3 (P1×1 / 3) respectively, which is convenient for monitoring the working condition.

[0019] In this embodiment, the hydrocyclone purification device 2, based on the centrifugal separation principle, is used to separate solid silt and impurities from the sealing water. The purified water is used as the shaft seal water and is detected as the primary pressure P1 input. The variable frequency booster pump 4 is used to ensure stable output of pressure P2 and tertiary pressure P3. The first electric pressure regulating valve 61 is used to achieve dynamic adjustment by combining with the PID controller 12 to output the secondary pressure P2. The second electric pressure regulating valve 62 is used to achieve secondary pressure relief by combining with the PID controller 12 to output the tertiary pressure P3 to the mud pump shaft seal assembly 5. The flow sensor 7 is used to monitor the sealing water flow rate and feed it back to the PID controller 12. The pressure sensor 10 is used to monitor the return water pressure, and the pressure speed regulating valve 11 is used to stabilize the return water flow rate. The residual water pipe 13 is used to discharge residual silt and solid particles from the sealing water.

[0020] In this embodiment, the mud pump shaft seal service device constructs a graded pressure system of "primary pressure P1, secondary pressure P2, and tertiary pressure P3," wherein, The primary pressure P1 is the pressure of the shaft end seal water pump, which matches the working conditions of the mud pump. The secondary pressure P2 is calculated and determined according to P1×2 / 3, and the downstream pressure is dynamically adjusted by the PID controller 12 in conjunction with the first electric pressure regulating valve 61. The third-level pressure P3 is calculated and determined according to P1×1 / 3, and secondary pressure relief is achieved by the PID controller 12 in conjunction with the second electric pressure regulating valve 62. After staged depressurization, the mud pump shaft seal assembly 5 actually bears a relative pressure of level three, P3. The first-level pressure P1 is set to 9 bar under sludge blowing conditions, corresponding to a second-level pressure P2 of 6 bar and a third-level pressure P3 of 3 bar.

[0021] In this embodiment, the output end of the hydrocyclone purification device 2 and the shaft seal lubrication and cooling channel of the mud pump shaft seal assembly 5 are a one-way flow channel to prevent the clean water from flowing back and carrying impurities.

[0022] In this embodiment, the variable frequency booster pump 4, the first electric pressure regulating valve 61, and the second electric pressure regulating valve 62 are all CNC pressure regulating valves. They form a closed-loop control with the PID controller 12 through the return water pressure detection signal to achieve precise pressure regulation.

[0023] Specific workflow: Seawater containing silt enters the hydrocyclone purification device 2 through the inlet pipe 1. Centrifugal force is used to separate silt particles with a diameter >0.1mm from the water. The purified water is used as the shaft seal water and first withstands the first-level pressure P1 (9 bar). Subsequently, the PID controller 12 controls the first electric pressure regulating valve 61 to adjust the pressure to the second-level pressure P2 (6 bar), achieving the first pressure relief. During this period, the variable frequency booster pump 4 works continuously to avoid water competition and ensure stable pressure output. Finally, the PID controller 12 controls the second electric pressure regulating valve 62 to adjust the pressure to the third-level pressure P3 (3 bar), achieving the second pressure relief. At this time, the shaft seal assembly 5 actually withstands a pressure of 3 bar, and the stress intensity is reduced by 67% compared with the traditional technology.

[0024] During operation, the operator can monitor the pressure values ​​at each level in real time through the pressure display unit 14. If it is necessary to discharge residual water and impurities, it can be done through the residual water drain pipe 13.

[0025] This invention effectively solves the failure problem of traditional mud pump shaft seals caused by mud and sand wear and high-pressure friction through a dual design of graded pressure relief and water purification. Actual tests show that the service life of the shaft seal can be extended to more than 1 year, significantly reducing the frequency of downtime maintenance and improving the efficiency of dredging operations by engineering vessels.

[0026] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mud pump shaft seal service device, characterized in that, include: The system includes a variable frequency booster pump, two sets of electric pressure regulating valves, a PID controller, a hydrocyclone purification device, and a piping system; the piping system includes one inlet pipe, two outlet pipes, and a residual water drain pipe. in, The water inlet pipe is used to connect to the branch pipe of the discharge water pump at the shaft end sealing water pump; The hydrocyclone purification device is connected in series downstream of the water inlet pipe; The variable frequency booster pump is connected in series downstream of the cyclone purifier; A one-way valve is provided between the cyclone purifier and the variable frequency booster pump; The downstream of the variable frequency booster pump is connected to the mud pump shaft seal assembly through two pipelines. Each of the two pipelines is equipped with an electric pressure regulating valve and a flow sensor. The electric pressure regulating valve includes a first electric pressure regulating valve and a second electric pressure regulating valve. The mud pump shaft seal assembly is connected to the mud pump suction port through two water outlet pipes; Each of the two water outlet pipes is equipped with a pressure sensor and a pressure speed regulating valve in sequence. The PID controller uses a closed-loop control to adjust the opening degree of the electronically controlled valve and the flow rate of the speed regulating valve. The residual water drain pipe is connected to the lowest point of the hydrocyclone purification device pipeline.

2. The mud pump shaft seal service device according to claim 1, characterized in that, The hydrocyclone purification device is used to separate solid mud and sand impurities from the sealing water. The purified water is used as shaft seal water and is detected as the first-level pressure P1 input.

3. The mud pump shaft seal service device according to claim 1, characterized in that, The variable frequency booster pump is used to ensure stable output of the secondary pressure P2 and the tertiary pressure P3.

4. The mud pump shaft seal service device according to claim 1, characterized in that, The first electric pressure regulating valve is used to dynamically regulate the pressure of the shaft end sealing water pump by combining with the PID controller, and output a secondary pressure P2.

5. A mud pump shaft seal service device according to claim 1, characterized in that, The second electric pressure regulating valve is used to achieve secondary pressure relief by combining with the PID controller, and is used to output a tertiary pressure P3 to the mud pump shaft seal assembly. The flow sensor is used to monitor the sealing water flow rate and feed it back to the PID controller.

6. The mud pump shaft seal service device according to claim 1, characterized in that, The pressure sensor is used to monitor the return water pressure, and the pressure regulating valve is used to stabilize the return water flow rate.

7. A mud pump shaft seal service device according to claim 1, characterized in that, The residual water pipe is used to drain residual mud, sand, and solid particles from the sealed water.

8. A mud pump shaft seal service device according to claim 1, characterized in that, The device constructs a graded pressure system of "primary pressure P1, secondary pressure P2, and tertiary pressure P3". in, The primary pressure P1 is the pressure of the shaft end seal water pump, which matches the working conditions of the mud pump. The secondary pressure P2 is calculated and determined according to P1×2 / 3, and the downstream pressure is dynamically adjusted by the PID controller in conjunction with the first electric pressure regulating valve. The third-level pressure P3 is calculated and determined according to P1×1 / 3, and secondary pressure relief is achieved by the PID controller in conjunction with the second electric pressure regulating valve. After staged pressure relief, the shaft seal assembly actually withstands a relative pressure of level three, P3. The first-level pressure P1 is set to 9 bar under sludge blowing conditions, corresponding to a second-level pressure P2 of 6 bar and a third-level pressure P3 of 3 bar.

9. A mud pump shaft seal service device according to claim 8, characterized in that, Also includes: Each pressure display unit displays the real-time values ​​of the first-level pressure P1, the second-level pressure P2, and the third-level pressure P3, respectively.

10. A mud pump shaft seal service device according to claim 1, characterized in that, The output end of the hydrocyclone purification device and the shaft seal lubrication and cooling channel of the mud pump shaft seal assembly form a unidirectional flow channel.

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