Stepped middle throttling seal of self-balancing multi-stage pump
By employing a stepped intermediate throttling seal structure and a high-frequency pressure pulsation sensor in the self-balancing multistage pump, the problem of easy damage to the seal structure is solved, achieving wear resistance and real-time monitoring of the seal structure, thereby improving the service life and efficiency of the self-balancing multistage pump.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HENAN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2025-06-30
- Publication Date
- 2026-05-12
AI Technical Summary
The intermediate throttling seal structure of a self-balancing multistage pump is susceptible to erosion and scouring by high-pressure fluid media, which leads to an increase in the sealing gap, affecting the pump's service life and hydraulic efficiency. Furthermore, existing technologies lack real-time monitoring methods.
It adopts a stepped intermediate throttling seal structure, combined with the alternating action of axial and radial sealing gaps, to reduce the scouring and erosion of high-pressure fluid media, and monitors the sealing force in real time through a high-frequency pressure pulsation sensor.
It effectively reduces wear on the intermediate throttling seal structure, extends service life, improves hydraulic efficiency, and enables real-time monitoring and prediction of the sealing gap.
Smart Images
Figure CN224228922U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of self-balancing multistage pump sealing technology, specifically to a stepped intermediate throttling seal for a self-balancing multistage pump. Background Technology
[0002] The self-balancing multistage pump adopts a back-to-back impeller arrangement, which allows the axial forces generated by the forward and reverse flow components to cancel each other out during operation. Compared with traditional multistage pumps, the axial force balancing structure is eliminated, and automatic axial thrust balancing can be achieved. It has now become a key drainage equipment in my country's mine drainage system.
[0003] The outlet section of a self-balancing multistage pump is located in the middle of the pump. During operation, the fluid medium pressures on both sides of the outlet section differ. Therefore, to effectively prevent the fluid medium in the high-pressure chamber of the outlet section from flowing back into the low-pressure chamber, an intermediate throttling seal structure, consisting of an intermediate throttling shaft sleeve and an intermediate throttling bushing, is typically used to isolate the high-pressure and low-pressure chambers. The sealing surfaces of the intermediate throttling shaft sleeve and bushing are primarily smooth straight-through seals, labyrinth seals, and spiral dynamic seals. However, when the high-pressure fluid medium in the high-pressure chamber of the outlet section enters the intermediate throttling seal gap, it causes strong scouring and erosion of the intermediate throttling seal structure, accelerating its failure rate. This is especially true as the number of impeller stages in the self-balancing multistage pump increases, further increasing the pressure difference between the fluid mediums on both sides of the outlet section and accelerating the failure rate of the intermediate throttling seal structure. As a core component of the self-balancing multistage pump, the service life of the intermediate throttling seal structure directly determines the overall service life of the pump. Therefore, based on the basic theory of fluid dynamics and the sealing mechanism of the sealing gap under pressure difference, developing a technology that can effectively isolate the fluid medium on both sides of the outlet section of a self-balancing multistage pump, while reducing the scouring and erosion damage rate of the high-pressure fluid medium on the intermediate throttling sealing structure, is a technical problem that urgently needs to be solved for self-balancing multistage pumps.
[0004] Furthermore, with prolonged operation of the self-balancing multistage pump, the sealing gap of its intermediate throttling seal structure will gradually increase. This causes a large amount of fluid medium in the high-pressure chamber of the outlet section to flow back into the low-pressure chamber along the intermediate throttling seal gap, resulting in increased volumetric losses and directly affecting the overall pump's hydraulic efficiency. Therefore, online detection of the sealing gap size of the intermediate throttling seal structure in a self-balancing multistage pump not only allows for real-time monitoring of the pump's operating status but also provides data support for timely replacement of the intermediate throttling seal structure. This prevents a decrease in the pump's hydraulic efficiency due to an increase in the sealing gap, thus providing technical support for energy conservation and consumption reduction in mine drainage systems. Utility Model Content
[0005] To address the aforementioned technical challenges, this invention proposes a stepped intermediate throttling seal structure. By alternating the axial and radial sealing gaps, the scouring and erosion damage of the intermediate throttling seal structure by the high-pressure fluid medium is reduced. Furthermore, a high-frequency pressure pulsation sensor is used to monitor the sealing force of the sealing fluid in the intermediate throttling seal structure in real time.
[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A stepped intermediate throttling seal for a self-balancing multi-stage pump, comprising intermediate throttling bushing A, intermediate throttling bushing B, intermediate throttling bushing, a high-frequency pressure pulsation sensor, and a controller. Intermediate throttling bushing A is mounted on the pump shaft via a flat key, near the low-pressure chamber of the outlet section. Intermediate throttling bushing B is mounted on the pump shaft via a flat key, near the high-pressure chamber of the outlet section. The intermediate throttling bushing is fixed to the center hole of the outlet section by four screws at its end. The outer diameter of the intermediate throttling bushing... The surface of the intermediate throttling bushing mates with the inner surface of the intermediate throttling bushing to form a stepped intermediate throttling sealing gap. The intermediate throttling sealing gap presents a symmetrical structure. The high-frequency pressure pulsation sensor is installed on the pressure pulsation measuring hole of the intermediate throttling bushing and close to the sealing gap of the intermediate throttling seal. The signal line of each high-frequency pressure pulsation sensor is connected to the controller through the pressure pulsation measuring hole of the intermediate throttling bushing and the sensor lead hole of the outlet section. The signal line of the controller output is connected to the transmitter installed on the outer circle of the outlet section through the outlet section lead hole of the outlet section.
[0007] Furthermore, the intermediate throttling bushing A and intermediate throttling bushing B are connected by a slot structure. An O-ring is provided at the mating position between intermediate throttling bushing A and intermediate throttling bushing B. Intermediate throttling bushing A and intermediate throttling bushing B together constitute an intermediate throttling bushing. The longitudinal cross-section of the intermediate throttling bushing is L-shaped. The outer circular surfaces of intermediate throttling bushing A and intermediate throttling bushing B are respectively provided with stepped structure. The stepped structure on the outer circular surface of intermediate throttling bushing A is symmetrically arranged with the stepped structure on the surface of intermediate throttling bushing B. A cladding layer is provided at the radial mating surface between intermediate throttling bushing B and intermediate throttling bushing.
[0008] Furthermore, the cladding layer of the intermediate throttling bushing B can be achieved through supersonic spraying, plasma welding, and laser cladding technology, and the material of the cladding layer is nickel-based hard alloy or chromium-based hard alloy.
[0009] Furthermore, the intermediate throttling bushing is composed of two symmetrical parts. The longitudinal cross-section of the intermediate throttling bushing is L-shaped. The inner hole of the intermediate throttling bushing is provided with a stepped structure. The stepped structure of the inner hole of the intermediate throttling bushing is symmetrical from left to right. Several pressure pulsation measuring holes are drilled on the outer circular surface of the intermediate throttling bushing to the inner hole of the intermediate throttling bushing by drilling.
[0010] Furthermore, the axial sealing gap between the intermediate throttling bushing and the intermediate throttling shaft sleeve can be a straight smooth seal, a labyrinth seal structure, or a spiral dynamic seal structure. That is, the outer circular surface of the intermediate throttling shaft sleeve can be provided with a labyrinth seal tooth structure or a spiral dynamic seal structure, which further improves the throttling sealing effect of the intermediate throttling shaft sleeve. Additionally, the inner bore surface of the intermediate throttling bushing can be provided with a labyrinth seal tooth structure or a spiral dynamic seal structure, which further improves the throttling sealing effect of the intermediate throttling bushing.
[0011] Furthermore, two sensor lead holes are provided on the water outlet section. The two sensor lead holes are arranged symmetrically from left to right. One end of the sensor lead hole is connected to the inner hole of the water outlet section, and the other end of the sensor lead hole is connected to the inner cavity of the water outlet section.
[0012] Compared with existing technologies, the stepped intermediate throttling seal of the self-balancing multistage pump described in this utility model firstly effectively reduces the pressure and velocity of the fluid medium entering the intermediate throttling seal gap through the radial mating end face between the intermediate throttling shaft sleeve B and the intermediate throttling bushing, thus avoiding the scouring and erosion damage of the intermediate throttling seal gap by the high-pressure fluid medium in the high-pressure chamber of the outlet section; secondly, the stepped intermediate throttling seal structure extends the length of the intermediate throttling seal gap through the alternating axial-radial-axial changes of the sealing gap channel, and more importantly, it can reduce the pressure and velocity of the fluid medium in the intermediate throttling seal gap, thereby significantly reducing the sealing fluid force in the intermediate throttling seal gap; finally, through a high-frequency pressure pulsation sensor, controller, and transmitter, real-time monitoring of the pressure pulsation of the fluid medium in the intermediate throttling seal gap can be realized, providing accurate data support for predicting the service life of the intermediate throttling seal structure and the sub-resonance instability of the self-balancing multistage pump rotor-seal system. Attached Figure Description
[0013] Figure 1 This is an overall structural diagram of the present invention;
[0014] Figure 2 for Figure 1 A magnified view of the intermediate throttling seal;
[0015] Figure 3This is a cross-sectional view of the three-dimensional model of the water outlet section of this utility model.
[0016] Figure 4 This is a three-dimensional cross-sectional view of the intermediate throttling shaft sleeve of this utility model;
[0017] Figure 5 This is a three-dimensional cross-sectional view of the intermediate throttling bushing B of this utility model;
[0018] Figure 6 This is a three-dimensional model of the intermediate throttling bushing of this utility model.
[0019] The markings in the diagram are as follows: 1: Inlet section; 2: Positive flow assembly; 3: Intermediate throttling seal; 31: Intermediate throttling bushing A; 32: Intermediate throttling bushing B; 321: Coating layer; 33: Intermediate throttling bushing; 331: Pressure pulsation measuring hole; 34: High-frequency pressure pulsation sensor; 35: Controller; 4: Outlet section; 41: Outlet section lead hole; 42: Low-pressure chamber; 43: High-pressure chamber; 44: Inner cavity; 45: Sensor lead hole; 5: Transition pipe; 6: Reverse flow assembly; 7: Secondary inlet section. Detailed Implementation
[0020] In the description of this utility model, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0021] To make the technical problem to be solved, the technical solution and the implementation effect of this utility model clearer, the following is in conjunction with the appendix. Figure 1-6 An embodiment of the present invention will be further described below:
[0022] See appendix Figure 1-6The present invention discloses a stepped intermediate throttling seal for a self-balancing multistage pump, comprising an intermediate throttling bushing A 31, an intermediate throttling bushing B 32, an intermediate throttling bushing 33, a high-frequency pressure pulsation sensor 34, and a controller 35. The intermediate throttling bushing A 31 is mounted on the pump shaft via a key and is located near the low-pressure chamber 42 of the outlet section 4. The intermediate throttling bushing B 32 is mounted on the pump shaft via a key and is located near the high-pressure chamber 43 of the outlet section 4. The intermediate throttling bushing 33 is fixed to the center hole of the outlet section 4 by four screws at its end. The outer surface of the intermediate throttling bushing and the intermediate throttling bushing 33 are aligned. The inner surface of the bushing 3 is matched to form a stepped intermediate throttling seal 3 gap. The intermediate throttling seal 3 gap presents a symmetrical structure. The high-frequency pressure pulsation sensor 34 is installed on the pressure pulsation measuring hole 331 of the intermediate throttling bushing 33 and close to the sealing gap of the intermediate throttling seal 3. The signal line of each high-frequency pressure pulsation sensor 34 is connected to the controller 35 through the pressure pulsation measuring hole 331 of the intermediate throttling bushing 33 and the sensor lead hole 45 of the water outlet section 4. The signal line of the controller 35 output terminal is connected to the transmitter installed on the outer circle of the water outlet section 4 through the water outlet section lead hole 41 of the water outlet section 4.
[0023] As a preferred embodiment, see Appendix Figure 2 , 4 In section 5, the intermediate throttling bushing A 31 and intermediate throttling bushing B 32 are connected by a slot structure. An O-ring is provided at the mating position between intermediate throttling bushing A 31 and intermediate throttling bushing B 32. The O-ring prevents the fluid medium in the intermediate throttling seal 3 gap from entering the gap between intermediate throttling bushing A 31, intermediate throttling bushing B 32 and the pump shaft, which can effectively avoid the corrosion effect of the fluid medium on the pump shaft. Intermediate throttling bushing A 31 and intermediate throttling bushing B 32 together constitute the intermediate throttling bushing. The longitudinal cross-section of the intermediate throttling bushing is L-shaped. The outer circular surfaces of intermediate throttling bushing A 31 and intermediate throttling bushing B 32 are respectively provided with stepped structure. The stepped structure on the outer circular surface of intermediate throttling bushing A 31 and the stepped structure on the surface of intermediate throttling bushing B 32 are symmetrically arranged. A cladding layer 321 is provided at the radial mating surface between intermediate throttling bushing B 32 and intermediate throttling bushing 33.
[0024] As a preferred embodiment, the cladding layer 321 of the intermediate throttling bushing 32 can be achieved by supersonic spraying, plasma welding and laser cladding technology, and the material of the cladding layer 321 is nickel-based hard alloy or chromium-based hard alloy.
[0025] In a preferred embodiment, the outer circular surface of the intermediate throttling bushing can be provided with a labyrinth sealing tooth structure or a spiral dynamic sealing structure, which further improves the throttling and sealing effect of the intermediate throttling bushing.
[0026] As a preferred embodiment, see Appendix Figure 2 and 6 The intermediate throttling bushing 33 is composed of two symmetrical parts. The longitudinal cross-section of the intermediate throttling bushing 33 is L-shaped. The inner hole of the intermediate throttling bushing 33 is provided with a stepped structure. The stepped structure of the inner hole of the intermediate throttling bushing 33 is symmetrical from left to right. Several pressure pulsation measuring holes 331 are drilled on the outer circular surface of the intermediate throttling bushing 33 to the inner hole of the intermediate throttling bushing 33 by drilling.
[0027] As a preferred embodiment, the inner surface of the intermediate throttling bushing 33 can be provided with a labyrinth sealing tooth structure or a spiral dynamic sealing structure, which further improves the throttling and sealing effect of the intermediate throttling bushing 33.
[0028] As a preferred embodiment, see Appendix Figure 1 and 3 Two sensor lead holes 45 are provided on the water outlet section 4. The two sensor lead holes 45 are arranged symmetrically from left to right. One end of the sensor lead hole 45 is connected to the inner hole of the water outlet section 4, and the other end of the sensor lead hole 45 is connected to the inner cavity 44 of the water outlet section 4.
[0029] In a preferred embodiment, the input terminal of the controller 35 receives the pressure pulsation signal of the fluid medium in the gap of the intermediate throttling seal 3 collected by the high-frequency pressure pulsation sensor 34 through the signal line, and sends the fluid medium pressure pulsation signal collected by the high-frequency pressure pulsation sensor 34 to the host computer through the transmitter connected to the output terminal of the controller 35.
[0030] As a preferred embodiment, see Appendix Figure 1 and 2The present invention discloses a stepped intermediate throttling seal for a self-balancing multistage pump. During assembly, firstly, after the inlet section 1 and the positive flow assembly 2 are assembled, the intermediate throttling bushing A 31 is installed on the pump shaft using a standard flat key, with its left end face contacting the hub end face of the last stage impeller of the positive flow assembly 2. Then, the controller 35, along with the signal lines connected to its input and output ends, are placed in the inner cavity 44 of the outlet section 4, and the controller 35 is fixed in the inner cavity 44 of the outlet section 4. Next, the left half of the intermediate throttling bushing 33 is installed. The signal lines connected to the input end of the controller 35 pass through the sensor lead hole 45 of the outlet section 4 and the intermediate throttling bushing 33, respectively. The pressure pulsation measuring hole 331 is led to the inner hole of the intermediate throttling bushing 33. Then, the right half of the intermediate throttling bushing 33 is installed in the inner hole of the outlet section 4. Then, several high-frequency pressure pulsation sensors 34 are connected to the signal lines of the input terminal of the controller 35, and the high-frequency pressure pulsation sensors 34 are installed in the pressure pulsation measuring hole 331 of the intermediate throttling bushing 33. Next, the outlet section 4 with the intermediate throttling bushing 33 installed is installed on the pump shaft. Then, the intermediate throttling bushing B 32 is installed on the pump shaft by ordinary flat key, and the right end face of the intermediate throttling bushing B 32 contacts the hub end face of the last stage impeller of the reverse flow assembly 6. Finally, the reverse flow assembly 6, the secondary inlet section 7 and the transition pipe 5 are installed.
[0031] The present invention discloses a stepped intermediate throttling seal for a self-balancing multistage pump. During normal operation of the self-balancing multistage pump, the low-pressure chamber 42 and high-pressure chamber 43 of the outlet section 4 are filled with high-pressure fluid medium, and the pressure of the fluid medium in the high-pressure chamber 43 is almost twice the pressure of the fluid medium in the low-pressure chamber 42. During pump operation, due to the axial lateral movement of the rotor system, a balance disc and balance ring structure is formed at the radial end face where the intermediate throttling bushing 32 and the intermediate throttling bushing 33 mate. The fluid medium in the high-pressure chamber 43 of the outlet section 4 enters the stepped sealing gap of the intermediate throttling seal 3 along the radial gap between the intermediate throttling bushing 32 and the intermediate throttling bushing 33, which greatly reduces the pressure of the high-pressure fluid medium in the high-pressure chamber 43 on the intermediate throttling seal 3. Erosion and scouring; In addition, the high-pressure fluid medium entering the intermediate throttling seal 3 gap flows along the stepped sealing gap. Through the alternating axial-radial-axial changes in the stepped sealing gap, the pressure and velocity of the fluid medium in the intermediate throttling seal 3 gap can be effectively reduced, thereby reducing the sealing fluid force of the sealing fluid in the intermediate throttling seal 3 gap and reducing the risk of sub-resonance instability of the self-balancing multistage pump rotor-seal system; On the other hand, the high-frequency pressure pulsation sensor 34 installed on the intermediate throttling bushing 33 monitors the pressure pulsation data of the fluid medium in the intermediate throttling seal 3 gap in real time and transmits it to the controller 35. Then, the transmitter sends the pressure pulsation data of the fluid medium in the intermediate throttling seal 3 gap to the host computer, realizing the real-time monitoring of the pressure pulsation data of the fluid medium in the intermediate throttling seal 3 gap.
[0032] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A stepped intermediate throttling seal for a self-balancing multistage pump, comprising intermediate throttling bushing A (31), intermediate throttling bushing B (32), intermediate throttling bushing (33), a high-frequency pressure pulsation sensor (34), and a controller (35), characterized in that: Intermediate throttling bushing A (31) is mounted on the pump shaft via a flat key and is located near the low-pressure chamber (42) of the outlet section (4). Intermediate throttling bushing B (32) is mounted on the pump shaft via a flat key and is located near the high-pressure chamber (43) of the outlet section (4). Intermediate throttling bushing (33) is fixed to the center hole of the outlet section (4) by four screws at its end. High-frequency pressure pulsation sensor (34) is mounted on the pressure pulsation measuring hole (331) of the intermediate throttling bushing (33) and is located near the sealing gap of the intermediate throttling seal (3). The signal line of each high-frequency pressure pulsation sensor (34) is connected to the controller (35) through the pressure pulsation measuring hole (331) of the intermediate throttling bushing (33) and the sensor lead hole (45) of the outlet section (4). The signal line of the controller (35) output is connected to the transmitter installed on the outer circle of the outlet section (4) through the outlet section lead hole (41) of the outlet section (4).
2. The stepped intermediate throttling seal of a self-balancing multistage pump according to claim 1, characterized in that: Intermediate throttling bushing A (31) and intermediate throttling bushing B (32) are connected by a slot structure. An O-ring is provided at the mating position between intermediate throttling bushing A (31) and intermediate throttling bushing B (32). Intermediate throttling bushing A (31) and intermediate throttling bushing B (32) together constitute an intermediate throttling bushing. The longitudinal cross-section of the intermediate throttling bushing is L-shaped. The outer circular surfaces of intermediate throttling bushing A (31) and intermediate throttling bushing B (32) are respectively provided with stepped structure. The stepped structure on the outer circular surface of intermediate throttling bushing A (31) and the stepped structure on the surface of intermediate throttling bushing B (32) are arranged symmetrically. A cladding layer (321) is provided at the radial mating surface between intermediate throttling bushing B (32) and intermediate throttling bushing (33).
3. The stepped intermediate throttling seal of a self-balancing multistage pump according to claim 1, characterized in that: The intermediate throttling bushing (33) is composed of two symmetrical parts. The longitudinal cross-section of the intermediate throttling bushing (33) is L-shaped. The inner hole of the intermediate throttling bushing (33) is provided with a stepped structure. The stepped structure of the inner hole of the intermediate throttling bushing (33) is symmetrical from left to right. Several pressure pulsation measuring holes (331) are provided on the outer circular surface of the intermediate throttling bushing (33).
4. The stepped intermediate throttling seal of a self-balancing multistage pump according to claim 1, characterized in that: Two sensor lead holes (45) are provided on the water outlet section (4). The two sensor lead holes (45) are arranged symmetrically from left to right. One end of the sensor lead hole (45) is connected to the inner hole of the water outlet section (4), and the other end of the sensor lead hole (45) is connected to the inner cavity (44) of the water outlet section (4).