Radial sealing structure based on front protective plate of submersible sewage pump
By setting a radial sealing structure between the front guard plate and the impeller of the submersible sewage pump, the problem of reduced efficiency caused by fluid backflow is solved, achieving higher sealing performance and efficiency, extending component life and reducing maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA RAILWAY 18TH BUREAU GRP CO LTD
- Filing Date
- 2025-05-29
- Publication Date
- 2026-05-12
AI Technical Summary
The existing submersible sewage pumps have a front guard plate that is only sealed to the impeller through an axial gap. This makes it easy for fluid to flow back from the impeller outlet to the impeller inlet along the axial gap, resulting in a reduction in pump efficiency.
A radial sealing structure, including a sealing step and an annular sealing surface, is set between the front guard plate and the impeller. Combined with the non-contact axial clearance, it forms a labyrinth seal to block the fluid backflow path.
It effectively reduces fluid leakage, improves the sealing performance and working efficiency of submersible sewage pumps, extends component life, reduces maintenance costs, and enhances equipment stability and reliability.
Smart Images
Figure CN224228929U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of submersible pump technology, specifically relating to a radial sealing structure based on the front guard plate of a submersible sewage pump. Background Technology
[0002] Submersible sewage pumps are particularly suitable for conveying liquids containing hard solids, fibrous materials, and especially dirty, viscous, and slippery liquids. They are widely used for conveying various types of domestic sewage, industrial wastewater, construction site drainage, liquid feed, etc., and play a very important role in various industries such as municipal engineering, industry, hospitals, construction, restaurants, and water conservancy construction.
[0003] Submersible sewage pumps mainly consist of an impeller, motor, volute, front guard plate, and rear guard plate. Since submersible sewage pumps may be used in harsh conditions such as high temperature, high pressure, and pollution, poor sealing can cause silt or sewage to enter the motor, damaging the motor and bearings, and affecting the life and reliability of the equipment.
[0004] The front and rear guard plates constitute the primary sealing structure of the motor. The front guard plate is located on the impeller inlet side and forms an axial clearance seal with the impeller to prevent large particles from entering the sealing area. The rear guard plate is located on the back of the impeller and forms an axial clearance seal with the impeller to reduce leakage of high-pressure liquid to the motor side.
[0005] The primary sealing structure of this submersible sewage pump currently has the following defects: the front guard plate and the impeller are only sealed by an axial gap, which can easily cause fluid to flow back from the impeller outlet along the axial gap between the front guard plate and the impeller to the impeller inlet, resulting in a reduction in pump efficiency. Utility Model Content
[0006] This utility model embodiment provides a radial sealing structure based on the front guard plate of a submersible sewage pump, which aims to reduce the problem of low pump efficiency caused by fluid leakage and backflow through radial sealing between the front guard plate and the impeller.
[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A radial sealing structure based on a front guard plate of a submersible sewage pump is provided, comprising: a volute, an impeller, and a front guard plate. The front guard plate is fixed to the front end face of the volute by bolts. The impeller is disposed within the volute and has a front hub extending towards the front guard plate. A sealing step is provided on the side of the front guard plate facing the front hub, and the sealing step has an annular sealing surface adapted to the circumferential surface of the front hub. The front hub and the front guard plate are rotatably engaged, so that the circumferential surface of the front hub and the annular sealing surface form a radial seal that blocks the fluid backflow path.
[0008] The sealing step also has a rear axial end face that is not in axial contact with the front wheel hub, and the rear axial end face and the front axial end face of the front wheel hub form a non-contact axial gap.
[0009] In one possible implementation, the front skid plate has a radial gap of 0.1-0.3 mm in width between it and the front wheel hub; the non-contact axial gap has a width of 0.5-1 mm.
[0010] In one feasible manner, the axial length of the annular sealing surface is greater than the radial length of the rear axial end face.
[0011] In one possible implementation, a limiting step is provided between the front end curved surface of the impeller and the circumferential surface of the front hub; an avoidance annular groove is provided on the rear end curved surface of the front guard plate to avoid the limiting step.
[0012] In one possible implementation, the clearance groove has a first sidewall perpendicular to the circumferential surface of the front wheel hub, and the first sidewall has a safety gap with the axial end face of the limiting step, the width of which is greater than the width of the non-contact axial gap.
[0013] In one possible implementation, a non-contact annular gap is formed between the front end surface of the impeller and the rear end surface of the front guard plate, which does not interfere with the rotation of the impeller.
[0014] In one possible implementation, the front guard plate further has a positioning step that abuts against the volute, the positioning step having a first axial end face that axially conforms to the volute and a first radial end face that radially conforms to the volute.
[0015] In one possible implementation, an annular groove is provided on the first radial end face, and a sealing ring is provided inside the annular groove.
[0016] In one feasible manner, the inlet diameter of the impeller gradually decreases from the outside to the inside.
[0017] In one feasible manner, the inlet diameter of the front guard plate gradually decreases from the outside to the inside.
[0018] The radial sealing structure based on the front guard plate of the submersible sewage pump provided by this utility model has the following advantages compared with the prior art: By setting a sealing step and an annular sealing surface adapted to the circumferential surface of the front hub on the front guard plate, the return flow path of fluid from the impeller outlet to the impeller inlet is blocked radially, achieving good radial sealing, reducing fluid leakage, and thus improving the sealing performance and working efficiency of the submersible sewage pump. At the same time, the non-contact axial clearance formed between the rear axial end face and the front axial end face of the front hub avoids direct contact wear between the two, extends the service life of components, reduces maintenance costs, and makes the entire submersible sewage pump more stable and reliable during operation, reducing the probability of failures caused by sealing problems and improving the overall performance and working quality of the equipment.
[0019] Since the impeller needs to rotate while the front guard plate is a fixed part, the front guard plate needs to seal the front end of the impeller and ensure that the rotation of the impeller is not interfered with. Therefore, the front guard plate and the impeller cannot be in a tight fit relationship. Thus, the seal of the impeller by the front guard plate also constitutes a dynamic seal at the inlet end.
[0020] When the impeller's front hub and the rear end of the front skid plate are axially sealed, a small axial gap still exists between them to ensure impeller rotation. Therefore, fluid will leak radially through this gap. Adding a radial seal to this axial seal significantly improves sealing performance. Since the fluid experiences primarily radial centrifugal force, it is less likely to pass through the radial gap between the front hub and the skid plate. Attached Figure Description
[0021] Figure 1 A schematic diagram of the radial sealing structure based on the front guard plate of a submersible sewage pump provided in an embodiment of this utility model;
[0022] Figure 2 for Figure 1 A magnified schematic diagram of the partial structure at point A in the middle;
[0023] Explanation of reference numerals in the attached figures:
[0024] 1. Pump shaft; 2. Impeller; 3. Volute; 4. Front guard plate; 5. Rear guard plate; 6. First radial end face; 7. First axial end face; 8. Sealing ring; 9. Non-contact annular gap; 10. Rear end curved surface; 11. Front end curved surface; 12. Circumvention ring groove; 13. Limiting step; 14. Annular sealing surface; 15. Rear axial end face; 16. Non-contact axial gap; 17. First sidewall. Detailed Implementation
[0025] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0026] In the claims, description, and accompanying drawings of this utility model, unless otherwise expressly defined, the terms "length," "width," "center," "inner," "outer," "axial," "radial," and "circumferential," etc., used to indicate orientation or positional relationships are based on the orientation and positional relationships shown in the drawings and are only for the convenience of describing the invention 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, and therefore should not be construed as limiting the specific scope of protection of the invention. Wherein, axial direction refers to the axial direction of the pump shaft, radial direction refers to the radial direction of the pump shaft, and the axial and radial directions of the impeller, front guard plate, and volute are all consistent with the pump shaft.
[0027] Please see Figure 1 and Figure 2 The radial sealing structure based on the front guard plate of the submersible sewage pump provided by this utility model is described below. The radial sealing structure based on the front guard plate 4 of the submersible sewage pump includes: a volute 3, an impeller 2, and a front guard plate 4. The front guard plate 4 is fixed to the front end face of the volute 3 by bolts. The impeller 2 is disposed inside the volute 3. The impeller 2 has a front hub extending in the direction of the front guard plate 4. A sealing step is provided on the side of the front guard plate 4 facing the front hub. The sealing step has an annular sealing surface 14 that adapts to the circumferential surface of the front hub. The front hub and the front guard plate 4 are rotatably engaged so that the circumferential surface of the front hub and the annular sealing surface 14 form a radial seal that blocks the fluid backflow path. The sealing step also has a rear axial end face 15 that is not in axial contact with the front hub. The rear axial end face 15 and the front axial end face of the front hub form a non-contact axial gap 16.
[0028] The radial sealing structure based on the front guard plate 4 of the submersible sewage pump provided by this utility model has the following advantages compared with the prior art: By setting a sealing step on the front guard plate 4 and an annular sealing surface 14 that adapts to the circumferential surface of the front hub, the backflow path of fluid from the outlet of the impeller 2 to the inlet of the impeller 2 can be effectively blocked (see...). Figure 1Arrow c points to the fluid return path; arrow a is the impeller 2 inlet (i.e., the fluid inlet); arrow b is the impeller 2 outlet (i.e., the fluid outlet). This ensures good radial sealing, reduces fluid leakage, and thus improves the sealing performance and efficiency of the submersible sewage pump. Simultaneously, the non-contact axial clearance 16 formed between the rear axial end face 15 and the front axial end face of the front hub retains its axial sealing function, preventing direct contact wear between the two, extending component lifespan, reducing maintenance costs, and making the entire submersible sewage pump more stable and reliable during operation. This reduces the probability of failures due to sealing problems and improves the overall performance and working quality of the equipment.
[0029] Since the impeller 2 needs to rotate, while the front guard plate 4 is a fixed part, the front guard plate 4 needs to seal the front end of the impeller 2 and also ensure that the rotation of the impeller 2 is not interfered with. Therefore, the front guard plate 4 and the impeller 2 cannot be in a tight fit relationship. Thus, the seal of the impeller 2 by the front guard plate 4 also constitutes a dynamic seal at the inlet end.
[0030] When the front hub of impeller 2 and the rear end of front guard plate 4 are axially sealed, a small axial gap still exists between the front hub and front guard plate 4 to ensure the rotation of impeller 2. Therefore, fluid can easily leak radially through the gap between the front hub and front guard plate 4. This application adds a radial seal to the axial seal. Since the fluid is subjected to primarily radial centrifugal force, it is less likely for the fluid to pass through the radial gap between the front hub and front guard plate 4, thus significantly improving the sealing performance.
[0031] Therefore, this application improves the fluid sealing performance by using radial and axial seals between the impeller front end and the front guard plate, thus preventing fluid from flowing back to the impeller inlet end.
[0032] It should be explained that the radial seal referred to in this application means the radial obstruction of axially flowing fluid between the front wheel hub and the front skid plate 4, see [link to relevant documentation]. Figure 1 As shown; similarly, an axial seal is an axial blockage of fluid flowing radially.
[0033] Furthermore, the radial and axial seals between the front guard plate 4 and the front hub of the impeller 2 are L-shaped bends, forming a labyrinth seal to reduce fluid backflow.
[0034] The functions of each component in this application are as follows:
[0035] The front guard plate 4 is installed on the inlet side of the volute 3 or impeller 2 and is fixed to the volute 3, usually by bolts or clamps. The front guard plate 4 and the front end of the impeller 2 form a dynamic seal at the inlet end to prevent large particles from entering the sealing area.
[0036] Front guard plate 4 is wear-resistant: made of high-chromium cast iron (Cr20 or above), stainless steel (such as 304 / 316) or tungsten carbide coating to resist solid particles; Front guard plate 4 is corrosion-resistant: for acidic / alkaline wastewater, duplex stainless steel or coating material should be selected.
[0037] The front guard plate 4 provides wear protection: it withstands the scouring of media containing solid particles, protecting the pump casing and mechanical seal. The front guard plate 4 also prevents leakage: together with the rear guard plate 5 and the mechanical seal, it ensures that sewage does not enter the motor cavity, preventing insulation failure or short circuits.
[0038] The rear guard plate 5 is located on the back of the impeller 2 and is fixed to the volute 3 or the motor housing to form a rear sealed cavity. The rear guard plate 5 fits with the rear end of the impeller 2 to control the axial clearance and reduce leakage of high-pressure liquid to the motor side.
[0039] The front guard plate 4, impeller 2, and rear guard plate 5 constitute a primary seal: the annular radial sealing surface of the front guard plate 4 forms a non-contact seal with the circumferential surface of the front hub of the impeller 2, reducing media leakage through hydrodynamic effects. The rear guard plate 5 has a clearance fit with the rear end of the impeller 2, forming a dynamic pressure barrier to balance axial forces and block impurities.
[0040] The mechanical seal located inside the mechanical seal chamber constitutes a secondary seal: as the last line of defense, the mechanical seal achieves absolute sealing through the tight fit of precision friction pairs, ensuring that the inside of the motor remains dry.
[0041] The impeller 2 is fixed to the pump shaft 1 by a key connection (or threaded locking) and rotates at high speed with the pump shaft 1.
[0042] In some embodiments, see Figure 1 and Figure 2 As shown, there is a radial gap of 0.1-0.3mm between the front skid plate 4 and the front wheel hub (not shown in the figure because the gap is very small); the width of the non-contact axial gap 16 is 0.5-1mm. Please analyze the effect through reasoning: when the radial gap is in the range of 0.1-0.3mm, it ensures that there is a certain buffer space between the front skid plate 4 and the front wheel hub, preventing direct contact and friction caused by minor vibrations or deviations during operation, reducing wear on parts and extending their service life; at the same time, it does not cause a decrease in sealing effect due to excessive gap.
[0043] For non-contact axial clearance 16 with a width of 0.5-1mm, this clearance setting allows the impeller 2 to have suitable room for movement in the axial direction, which can accommodate the axial displacement that may occur during the operation of the impeller 2 and prevent damage to the components due to axial compression or collision.
[0044] In some embodiments, see Figure 1 and Figure 2The axial length of the annular sealing surface 14 is greater than the radial length of the rear axial end face 15. The longer annular sealing surface 14 improves the reliability of the radial seal between the front guard plate 4 and the front hub, thereby preventing fluid from flowing back from the impeller 2 outlet through the space between the front guard plate 4 and the front hub to the impeller 2 inlet, ensuring the working efficiency of the submersible sewage pump.
[0045] In some embodiments, see Figure 1 and Figure 2 A limiting step 13 is provided between the front curved surface 11 of the impeller 2 and the circumferential surface of the front hub; a clearance annular groove 12 is provided on the rear curved surface 10 of the front guard plate 4 to avoid the limiting step 13. When the impeller 2 may undergo axial displacement during operation, the limiting step 13 can prevent the impeller 2 from contacting, colliding, and rubbing against the front guard plate 4 over a large area, because the limiting step 13 will first contact the front guard plate 4 axially; and the sharp corner of the limiting step 13 faces the clearance annular groove 12, which also avoids the sharp corner of the limiting step 13 from scraping, colliding, and making abnormal noises with the front guard plate 4.
[0046] In some embodiments, see Figure 1 and Figure 2 The avoidance groove 12 has a first sidewall 17 perpendicular to the circumferential surface of the front hub. A safety gap exists between the first sidewall 17 and the axial end face of the limiting step 13, the width of which is greater than the width of the non-contact axial clearance 16. When the impeller 2 experiences vibration or displacement during operation, the greater width of the safety gap than the non-contact axial clearance 16 effectively prevents the first sidewall 17 from colliding with the axial end face of the limiting step 13, thus protecting the structural integrity of the front hub, reducing the risk of damage to the front hub due to collision, ensuring the normal operation of the impeller 2, and improving the stability and reliability of the entire pump.
[0047] In some embodiments, see Figure 1 and Figure 2 The front end curved surface 11 of the impeller 2 and the rear end curved surface 10 of the front guard plate 4 form a non-contact annular gap 9 that does not interfere with the rotation of the impeller 2.
[0048] The non-contact annular gap 9 can effectively reduce the frictional loss between the impeller 2 and the front guard plate 4 when the impeller 2 rotates; on the other hand, it avoids direct contact between the impeller 2 and the front guard plate 4, greatly reduces the wear of parts, extends the service life of the impeller 2 and the front guard plate 4, and reduces the maintenance cost of the equipment.
[0049] In some embodiments, see Figure 1As shown, the front skid plate 4 also has a positioning step that abuts against the volute 3. The positioning step has a first axial end face 7 that axially fits against the volute 3 and a first radial end face 6 that radially fits against the volute 3. The first axial end face 7 of the positioning step axially fits against the volute 3, which can effectively limit the axial displacement of the front skid plate 4 and ensure the accuracy and stability of its installation position. At the same time, the first radial end face 6 radially fits against the volute 3, which further enhances the tightness of the connection between the front skid plate 4 and the volute 3 and prevents relative shaking or displacement between the two in the radial direction. This not only helps to improve the sealing performance of the entire structure but also reduces the risk of possible leakage.
[0050] In some embodiments, see Figure 1 As shown, an annular groove is provided on the first radial end face 6, and a sealing ring 8 is provided in the annular groove to play a good sealing role, preventing fluid (such as liquid) from leaking between the contact surface of the front guard plate 4 and the volute 3, and reducing potential safety hazards and resource waste caused by leakage.
[0051] In some embodiments, see Figure 1 As shown, the inlet diameter D1 of impeller 2 gradually decreases from the outside to the inside. This design allows the fluid to form a more concentrated and accelerated flow pattern when entering impeller 2, effectively increasing the initial kinetic energy of the fluid and thus improving the work efficiency of impeller 2. Secondly, this gradually decreasing inlet diameter helps optimize the flow field distribution of the fluid at the inlet of impeller 2, reducing flow losses and energy dissipation, making the energy conversion of the entire system more efficient. Furthermore, it enhances the impeller 2's ability to draw in fluid, avoiding fluid accumulation or poor flow at the inlet, ensuring the stable operation of impeller 2, reducing vibration and noise problems that may be caused by abnormal inlet flow, extending the service life of the equipment, and improving the reliability and stability of equipment operation.
[0052] In some embodiments, see Figure 1 As shown, the inlet diameter D2 of the front guard plate 4 gradually decreases from the outside to the inside, and the inlet diameter of the impeller 2 also gradually decreases from the outside to the inside. Therefore, the overall inlet diameter of the fluid gradually decreases from the outside to the inside. Specifically, the cross-sectional area at the minimum diameter of the inlet diameter D2 of the front guard plate 4 is not less than the cross-sectional area at the impeller inlet.
[0053] This design allows the incoming fluid to be more concentrated, increasing the speed and pressure of fluid flow. Furthermore, this shape helps optimize fluid dynamics performance, reducing turbulence and cavitation generated when the fluid enters the front guard plate 4, allowing the fluid to enter the volute 3 more smoothly, and improving overall operating efficiency.
[0054] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.
[0055] The above description is only a preferred embodiment of the present utility model and is 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 radial sealing structure based on the front guard plate of a submersible sewage pump, comprising: The volute (3), impeller (2), and front guard plate (4) are provided. The front guard plate (4) is fixed to the front end face of the volute (3) by bolts. The impeller (2) is disposed inside the volute (3). The impeller (2) has a front hub extending toward the front guard plate (4). The front guard plate (4) has a sealing step on the side facing the front hub. The sealing step has an annular sealing surface (14) that is adapted to the circumferential surface of the front hub. The front hub and the front guard plate (4) are rotatably engaged so that the circumferential surface of the front hub and the annular sealing surface (14) form a radial seal that blocks the fluid return path. The sealing step also has a rear axial end face (15) that is not in axial contact with the front wheel hub, and the rear axial end face (15) and the front axial end face of the front wheel hub form a non-contact axial gap (16).
2. The radial sealing structure based on the front guard plate of the submersible sewage pump as described in claim 1, characterized in that, The front guard plate (4) has a radial gap of 0.1-0.3 mm between it and the front wheel hub; the non-contact axial gap (16) has a width of 0.5-1 mm.
3. The radial sealing structure based on the front guard plate of the submersible sewage pump as described in claim 1, characterized in that, The axial length of the annular sealing surface (14) is greater than the radial length of the rear axial end face (15).
4. The radial sealing structure based on the front guard plate of the submersible sewage pump as described in claim 1, characterized in that, A limiting step (13) is provided between the front end curved surface (11) of the impeller (2) and the circumferential surface of the front hub; an avoidance annular groove (12) is provided on the rear end curved surface (10) of the front guard plate (4) to avoid the limiting step (13).
5. The radial sealing structure based on the front guard plate of the submersible sewage pump as described in claim 4, characterized in that, The clearance groove (12) has a first sidewall (17) perpendicular to the circumferential surface of the front wheel hub. The first sidewall (17) has a safety gap with the axial end face of the limiting step (13). The width of the safety gap is greater than the width of the non-contact axial gap (16).
6. The radial sealing structure based on the front guard plate of the submersible sewage pump as described in claim 4, characterized in that, The front end curved surface (11) of the impeller (2) and the rear end curved surface (10) of the front guard plate (4) form a non-contact annular gap (9) that does not interfere with the rotation of the impeller (2).
7. The radial sealing structure based on the front guard plate of a submersible sewage pump as described in claim 1, characterized in that, The front guard plate (4) also has a positioning step that abuts against the volute (3), the positioning step having a first axial end face (7) that axially fits the volute (3) and a first radial end face (6) that radially fits the volute (3).
8. The radial sealing structure based on the front guard plate of the submersible sewage pump as described in claim 7, characterized in that, An annular groove is provided on the first radial end face (6), and a sealing ring (8) is provided in the annular groove.
9. The radial sealing structure based on the front guard plate of a submersible sewage pump as described in claim 1, characterized in that, The inlet diameter of the impeller (2) gradually decreases from the outside to the inside.
10. The radial sealing structure based on the front guard plate of a submersible sewage pump as described in claim 9, characterized in that, The inlet diameter of the front guard plate (4) gradually decreases from the outside to the inside.