A submersible sewage pump

Abstract

This application relates to the field of sewage pump technology and discloses a submersible sewage pump, including a casing, a motor, an impeller, a wear-resistant plate, and an elastic element. The casing includes a motor housing, a pump housing, and an oil chamber housing, with the oil chamber housing connected between the motor housing and the pump housing. A base is connected to the end of the pump housing furthest from the oil chamber housing. The motor is located inside the motor housing, and its main shaft extends through the oil chamber housing into the pump housing and connects to the impeller to drive its rotation. The wear-resistant plate is located inside the pump housing, below the impeller, and defines an installation space between the wear-resistant plate and the base. The elastic element is located within the installation space, with one end abutting against the wear-resistant plate and the other end abutting against the base. Utilizing the elastic force generated by the compression or rebound of the elastic element, the wear-resistant plate is axially displaced relative to the impeller, achieving real-time dynamic compensation of the clearance. This effectively avoids the impeller jamming problem caused by dirt accumulation in traditional fixed-clearance designs.

Description

Technical Field

[0001] This utility model relates to the field of sewage pump technology, and in particular to a submersible sewage pump. Background Technology

[0002] In the field of submersible pump technology, submersible sewage pumps, as key equipment for treating sewage containing solid impurities and fibrous materials, are widely used in municipal sewage treatment, industrial wastewater discharge, and building foundation pit drainage. Among them, the cutting submersible sewage pump has a tearing structure that can tear and cut long fibers, bags, belts, strips of cloth, and other materials in sewage, and then discharge them smoothly. It is particularly suitable for conveying liquids containing hard solids, fibrous materials, and particularly dirty, sticky, and slippery liquids.

[0003] In existing technologies, the impeller and side grinding plate (also known as wear-resistant plate or thrust plate) of a cutting submersible sewage pump are key mating components. A certain clearance must be reserved between them to ensure the normal rotation of the impeller. At the same time, this clearance must also meet the requirements of sealing, preventing leakage, and reducing fluid backflow. Currently, most cutting submersible sewage pumps on the market adopt a fixed clearance design, that is, the relative position of the impeller and the side grinding plate is fixed by components such as the pump body structure, bearing housing, or positioning pins. After assembly, the clearance value remains constant and cannot be dynamically adjusted according to actual working conditions. Because the sewage medium treated by the cutting submersible sewage pump contains a large amount of irregular solid dirt, during the operation of the pump, some dirt that is not completely cut (such as long fibers, plastic fragments, entangled materials, etc.) is easily sucked into the gap between the impeller and the side grinding plate. As the operating time increases, these dirt will gradually accumulate, entangle, and compact in the gap, causing the gap to be completely blocked. When the amount of dirt accumulated in the gap reaches a certain level, it will form a rigid obstruction, restricting the rotational freedom of the impeller, eventually causing the impeller to jam and the pump to fail to operate normally. Utility Model Content

[0004] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, this application provides a submersible sewage pump.

[0005] This application provides a submersible sewage pump, comprising: The housing includes a motor housing, a pump housing, and an oil chamber housing, wherein the oil chamber housing is connected between the motor housing and the pump housing, and a base is connected to the end of the pump housing away from the oil chamber housing. An electric motor is housed within the motor housing, and the main shaft of the motor extends through the oil chamber housing into the pump housing. An impeller is disposed inside the pump casing, and the portion of the main shaft extending into the pump casing is connected to the impeller so as to drive the impeller to rotate; A wear-resistant plate is disposed inside the pump casing and located below the impeller, and an installation space is defined between the wear-resistant plate and the base; An elastic element is disposed within the installation space. One end of the elastic element abuts against the wear-resistant plate, and the other end abuts against the base. The elastic element can generate an elastic force to drive the wear-resistant plate to move axially along the pump casing, thereby adjusting the gap between the impeller and the wear-resistant plate.

[0006] In one embodiment, the elastic element is a wave spring arranged in a ring shape; wherein the wave spring includes multiple peaks and multiple troughs, the peaks and troughs are alternately distributed along the circumference of the wave spring, all the peaks have the same amplitude, all the troughs have the same amplitude, and the peaks abut against the end face of one of the wear-resistant plate and the base, and the troughs abut against the end face of the other.

[0007] In one embodiment, the distance between two adjacent troughs is The distance between two adjacent wave peaks is ;in, and The following relationship must be satisfied: .

[0008] In one embodiment, the base has an annular boss on the end face facing the wear-resistant plate, and the wear-resistant plate has an annular abutment extending downward from the end face facing the base. The crest of the wave spring abuts against the abutment, and the trough of the wave spring abuts against the annular boss.

[0009] In one embodiment, the width of the wave spring is less than or equal to the width of the annular boss; and the width of the wave spring is less than or equal to the width of the abutment portion.

[0010] In one embodiment, a stepped groove is formed between the annular boss and the end face of the base facing the wear-resistant plate, and the end face of the pump housing away from the oil chamber abuts against the bottom of the stepped groove.

[0011] In one embodiment, a mechanical seal assembly is provided inside the oil chamber shell, and the mechanical seal assembly is sleeved on the outer periphery of the main shaft; wherein, the mechanical seal assembly includes a rotating ring and a stationary ring, the rotating ring is connected to the main shaft and can rotate synchronously with the main shaft, the stationary ring is connected to the oil chamber shell and remains stationary, and the rotating ring and the stationary ring are in contact to form a sealing surface.

[0012] In one embodiment, the submersible sewage pump further includes an oil seal skeleton, which is sleeved on the outer periphery of the main shaft and located inside the oil chamber shell and close to the pump shell. The outer peripheral wall of the oil seal skeleton is tightly fitted with the inner wall of the oil chamber shell to form a sealed space inside the oil chamber shell.

[0013] In one embodiment, the outer peripheral wall of the oil seal skeleton extends with a lip, and an abutment portion is provided inside the oil chamber shell and on the side near the pump shell; when the oil seal skeleton is fitted onto the main shaft, the lip and the lower end face of the abutment portion are tightly fitted to prevent the lubricating oil in the oil chamber shell from leaking into the pump shell.

[0014] In one embodiment, the pump housing has an outwardly extending outlet that communicates with the interior of the pump housing to discharge liquid pressurized by the impeller outside the pump housing.

[0015] The technical solutions provided in this application have the following advantages compared with the prior art: By defining an installation space between the base and the wear-resistant plate, and setting an elastic element within the installation space, the two ends of the elastic element abut against the base and the wear-resistant plate respectively. Then, by utilizing the elastic force generated by the compression or rebound of the elastic element itself, the wear-resistant plate is driven to move axially relative to the impeller, realizing real-time dynamic compensation of the gap. This effectively avoids the impeller jamming problem caused by dirt accumulation in traditional fixed gap designs, and significantly improves the operational stability and reliability of submersible sewage pumps under complex working conditions. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] In the attached image: Figure 1 This is a cross-sectional schematic diagram of a submersible sewage pump according to this application; Figure 2 yes Figure 1 Enlarged view of point A in the middle; Figure 3 This is a schematic diagram of the wave spring structure in a submersible sewage pump according to this application; Figure 4 yes Figure 1 Enlarged diagram of point B in the middle.

[0019] Icon labels: 10. Housing; 11. Motor housing; 12. Oil chamber housing; 13. Pump housing; 20. Base; 30. Motor; 31. Main shaft; 40. Impeller; 50. Wear-resistant plate; 60. Elastic element; 70. Mechanical seal assembly; 80. Oil seal skeleton; 80a. Lip; 90. Stepped groove; 100. Installation space. Detailed Implementation

[0020] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or component referred to must have a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0021] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0022] In the following description, specific details such as particular system structures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art will understand that the present invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0023] Please refer to Figure 1 and Figure 2This application provides a submersible sewage pump, which includes a housing 10, a motor 30, an impeller 40, and a wear-resistant plate 50.

[0024] Specifically, the housing 10 includes a motor housing 11, a pump housing 13, and an oil chamber housing 12. The oil chamber housing 12 is located between the motor housing 11 and the pump housing 13, and its two ends are fixedly connected to the ends of the motor housing 11 and the pump housing 13, respectively. Specifically, the oil chamber housing 12 can be fixed to the motor housing 11 and the pump housing 13 by means including but not limited to bolt connection, flange connection, or welding to ensure the overall structural stability and sealing of the housing 10.

[0025] The motor 30 is housed within the motor housing 11. The main shaft 31 of the motor 30 extends through the oil chamber housing 12 into the pump housing 13 and is connected to the impeller 40 located within the pump housing 13, enabling the motor 30 to drive the rotating shaft and rotate the impeller 40. A wear-resistant plate 50 is located within the pump housing 13 and below the impeller 40. The pump housing 13 has an outwardly extending outlet that connects to the interior of the pump housing 13, allowing the liquid pressurized by the impeller 40 to be discharged outside the pump housing 13. In other words, when discharging sewage, the sewage enters through the inlet area of ​​the pump housing 13. The motor 30 then drives the main shaft 31 to rotate, causing the impeller 40 to rotate at high speed, generating centrifugal force to pressurize the incoming sewage, which is then discharged through the outlet of the pump housing 13. It should be noted that the motor 30 in this embodiment is common knowledge in the art, and its specific structure and the method of driving the main shaft 31 to rotate are not described in detail.

[0026] In practical applications, to ensure the normal rotation of the impeller 40, a certain gap needs to be reserved between the impeller 40 and the wear-resistant plate 50. However, during pump operation, some incompletely cut contaminants (such as long fibers, plastic fragments, entangled materials, etc.) are easily sucked into the gap between the impeller 40 and the side wear plate, and gradually accumulate, entangle, and compact within the gap, causing the gap to be completely blocked, thus causing the impeller 40 to jam and the pump to be unable to operate normally. To address this, in one embodiment, an installation space 100 is defined between the wear-resistant plate 50 and the base 20, and an elastic element 60 is disposed within the installation space 100. One end of the elastic element 60 abuts against the wear-resistant plate 50, and the other end abuts against the base 20. The elastic element 60 can generate an elastic force to drive the wear-resistant plate 50 to move axially along the pump casing 13, thereby adjusting the gap between the impeller 40 and the wear-resistant plate 50.

[0027] Specifically, when the gap between the impeller 40 and the wear-resistant plate 50 changes due to the accumulation of dirt or wear of components, the elastic element 60 can drive the wear-resistant plate 50 to move axially relative to the impeller 40 through its own compression or rebound, thereby achieving real-time dynamic compensation of the gap. For example, in the initial stage of pump operation, the initial gap between the impeller 40 and the wear-resistant plate 50 is set to 0.3-0.5mm to ensure smooth rotation of the impeller 40. When solid particles or fibrous debris in the sewage enter the gap and gradually accumulate, the accumulation is squeezed during the rotation of the impeller 40, which generates a downward thrust on the wear-resistant plate 50, causing the wear-resistant plate 50 to move closer to the base 20, thereby increasing the gap between the impeller 40 and the wear-resistant plate 50. The blocked debris can be discharged through this gap, and at this time, the elastic element 60 is in a compressed state. After the debris is discharged, the elastic element 60 recovers its deformation and applies an upward elastic force to the wear-resistant plate 50, pushing the wear-resistant plate 50 to reset, so that the impeller 40 and the wear-resistant plate 50 maintain the preset fit gap again, so as to ensure the normal operation efficiency of the submersible sewage pump.

[0028] In summary, the submersible sewage pump of this application defines an installation space 100 between the base 20 and the wear-resistant plate 50, and sets an elastic element 60 within the installation space 100 so that both ends of the elastic element 60 abut against the base 20 and the wear-resistant plate 50 respectively. Then, by utilizing the elastic force generated by the compression or rebound of the elastic element 60 itself, the wear-resistant plate 50 is driven to move axially relative to the impeller 40, realizing real-time dynamic compensation of the gap. This can effectively avoid the problem of impeller 40 jamming due to the accumulation of dirt in traditional fixed gap designs, and significantly improve the operational stability and reliability of the submersible sewage pump under complex working conditions.

[0029] Because wave springs are small in size, have good elasticity, and stable stiffness, they can provide a continuous and stable elastic force within a relatively small installation space of 100. Therefore, please refer to... Figure 2 and Figure 3 In one embodiment, the elastic element 60 is preferably a wave spring, and the wave spring is arranged in a ring so that it can be adapted to the circular contact surface of the wear-resistant plate 50 and the base 20 to ensure that a uniform supporting force is applied to the wear-resistant plate 50.

[0030] In a specific embodiment, the wave spring includes multiple peaks and multiple troughs, which are alternately distributed circumferentially along the wave spring. All peaks have the same amplitude, and all troughs have the same amplitude. Each peak abuts against the end face of either the wear-resistant plate 50 or the base 20, while each trough abuts against the end face of the other. In other words, by limiting the amplitudes of the multiple peaks and troughs of the wave spring to be the same, after the wave spring is installed in the installation space 100, it is ensured that all peaks abut against the end face of the wear-resistant plate 50, and all troughs abut against the end face of the base 20. This ensures that the elastic force applied to the wear-resistant plate 50 by the wave spring during compression or rebound is evenly distributed, preventing uneven force from causing the wear-resistant plate 50 to tilt and affecting the gap compensation accuracy. For example, when the crests abut against the wear-resistant plate 50 and the troughs abut against the base 20, the upward supporting force on the wear-resistant plate 50 is provided by multiple evenly distributed crests, so that the wear-resistant plate 50 always remains horizontal during axial movement, ensuring that the gap between the impeller 40 and the wear-resistant plate 50 is uniform and consistent along the circumference.

[0031] It should be noted that the number of crests and troughs in the wave spring can be designed according to actual working conditions. For example, in scenarios requiring high elastic force, the number of crests and troughs can be increased to improve the overall stiffness of the spring. Conversely, in situations where installation space is limited, the amplitude of the crests and troughs can be adjusted to balance elastic performance and space occupancy. Furthermore, the wave spring is made of corrosion-resistant materials such as stainless steel, effectively resisting the erosion of corrosive media in sewage, ensuring the stability of its elastic performance during long-term use, and extending the maintenance cycle of the submersible sewage pump.

[0032] Please refer to Figure 3 In one implementation, the distance between two adjacent troughs is The distance between two adjacent wave crests is ;in, and The following relationship must be satisfied: Thus, through limitation and The range of differences can further optimize the force distribution characteristics of the wave spring. For example: when equal When the wave crests and troughs of the wave spring are perfectly symmetrically distributed, the deformation of each crest tends to be uniform during compression, achieving optimal uniformity of support force on the wear-resistant plate 50; while when Slightly larger When the difference does not exceed 0.5mm, the elastic force requirement under specific working conditions can be adapted by finely adjusting the peak spacing while ensuring overall symmetry.

[0033] In one embodiment, the end face of the seat facing the wear-resistant plate 50 is provided with an annular boss, and the end face of the wear-resistant plate 50 facing the base 20 extends downward with an annular abutment portion. The crest of the wave spring abuts against the abutment portion, and the trough of the wave spring abuts against the annular boss. In this way, after the wave spring is installed into the installation space 100, the crest of the wave spring abuts against the abutment portion, and the trough abuts against the annular boss. Through this double limiting structure, the precise positioning of the wave spring is achieved, and the axial force on the wear-resistant plate 50 is evenly transmitted from the crest to the trough, and then distributed to the base 20 via the annular boss, avoiding component deformation caused by stress concentration. For example, when dirt enters the gap between the impeller 40 and the wear-resistant plate 50 and pushes the wear-resistant plate 50 downward, the abutting part simultaneously squeezes the crest of the wave spring, causing the crest to undergo elastic deformation and transmit the pressure to the trough. The trough then transmits the force to the base 20 through the annular boss. At this time, the annular boss and the abutting part together restrict the radial displacement of the wave spring, ensuring that the spring is always compressed along the axial direction and guaranteeing the linear accuracy of the gap compensation.

[0034] Furthermore, the width of the wave spring is less than or equal to the width of the annular boss; and the width of the wave spring is less than or equal to the width of the abutment portion. This effectively prevents the wave spring from shifting laterally or twisting during the application of force, ensuring that the contact area between the spring, the annular boss, and the abutment portion remains stable.

[0035] For example, when the width of the wave spring is equal to the width of the annular boss, the trough of the spring can completely cover the end face of the annular boss, making the pressure transmission more uniform. If the width of the wave spring is slightly smaller than the width of the annular boss, a certain radial adjustment margin can be provided for the spring during assembly, which is convenient for fine-tuning the position of the spring during installation, while still ensuring that the trough and the main force-bearing area of ​​the annular boss are in full contact.

[0036] In one embodiment, a stepped groove 90 is formed between the annular boss and the end face of the base 20 facing the wear plate 50, and the end face of the pump housing 13 away from the oil chamber housing 12 abuts against the bottom of the stepped groove 90.

[0037] Please refer to Figure 1In one embodiment, a mechanical seal assembly 70 is provided inside the oil chamber shell 12, and the mechanical seal assembly 70 is sleeved on the outer periphery of the main shaft 31. The mechanical seal assembly 70 includes a rotating ring and a stationary ring. The rotating ring is connected to the main shaft 31 and can rotate synchronously with the main shaft 31, while the stationary ring is connected to the oil chamber shell 12 and remains stationary. The rotating ring and the stationary ring are in contact to form a sealing surface. That is, because the rotating ring is sleeved on the main shaft 31 and the stationary ring is fixed to the oil chamber shell 12, the rotating ring can rotate synchronously when the main shaft 31 rotates, and the sealing surface formed by the tight contact with the stationary ring can maintain a continuous contact state when the main shaft 31 rotates at high speed. This cuts off the path of leakage of the medium through the gap between the main shaft 31 and the oil chamber shell 12, protecting core components such as the motor 30 from corrosion or damage.

[0038] Please refer to Figure 1 and Figure 4 In one embodiment, the submersible sewage pump also includes an oil seal skeleton 80, which is sleeved on the outer periphery of the main shaft 31 and located inside the oil chamber shell 12 and close to the side of the pump shell 13. The outer peripheral wall of the oil seal skeleton 80 is tightly fitted with the inner wall of the oil chamber shell 12 so that a sealed space is formed inside the oil chamber shell 12.

[0039] Specifically, the outer peripheral wall of the oil seal skeleton 80 extends with a lip 80a, and an abutment portion is provided inside the oil chamber shell 12 on the side near the pump shell 13. When the oil seal skeleton 80 is fitted onto the main shaft 31, the lip 80a fits tightly against the lower end face of the abutment portion to prevent lubricating oil in the oil chamber shell 12 from leaking into the pump shell 13. In other words, by setting the oil seal skeleton 80 and utilizing the tight fit between its lip 80a and the abutment portion of the oil chamber shell 12, as well as the tight fit with the main shaft 31, it is possible to effectively prevent lubricating oil in the oil chamber shell 12 from leaking into the pump shell 13, while also preventing sewage or impurities in the pump shell 13 from entering the oil chamber shell 12. This provides a good lubrication and working environment for key components such as the mechanical seal assembly 70, thereby ensuring the long-term stable operation of the submersible sewage pump.

[0040] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present utility model, all of which fall within the protection scope of the present utility model. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.

Claims

1. A submersible sewage pump, characterized in that, include: The housing includes a motor housing, a pump housing, and an oil chamber housing, wherein the oil chamber housing is connected between the motor housing and the pump housing, and a base is connected to the end of the pump housing away from the oil chamber housing. An electric motor is housed within the motor housing, and the main shaft of the motor extends through the oil chamber housing into the pump housing. An impeller is disposed inside the pump casing, and the portion of the main shaft extending into the pump casing is connected to the impeller so as to drive the impeller to rotate; A wear-resistant plate is disposed inside the pump casing and located below the impeller, and an installation space is defined between the wear-resistant plate and the base; An elastic element is disposed within the installation space. One end of the elastic element abuts against the wear-resistant plate, and the other end abuts against the base. The elastic element can generate an elastic force to drive the wear-resistant plate to move axially along the pump casing, thereby adjusting the gap between the impeller and the wear-resistant plate.

2. The submersible sewage pump according to claim 1, characterized in that, The elastic element is a wave spring arranged in a ring shape; wherein the wave spring includes multiple peaks and multiple troughs, the peaks and troughs are alternately distributed along the circumference of the wave spring, all the peaks have the same amplitude, all the troughs have the same amplitude, and the peaks abut against the end face of one of the wear-resistant plate and the base, and the troughs abut against the end face of the other.

3. The submersible sewage pump according to claim 2, characterized in that, The distance between two adjacent troughs is The distance between two adjacent wave peaks is ;in, and The following relationship must be satisfied: .

4. The submersible sewage pump according to claim 2, characterized in that, The base has an annular boss on the end face facing the wear-resistant plate, and the wear-resistant plate has an annular abutment extending downward from the end face facing the base. The crest of the wave spring abuts against the abutment, and the trough of the wave spring abuts against the annular boss.

5. The submersible sewage pump according to claim 4, characterized in that, The width of the wave spring is less than or equal to the width of the annular boss; and the width of the wave spring is less than or equal to the width of the abutment portion.

6. The submersible sewage pump according to claim 4, characterized in that, A stepped groove is formed between the annular boss and the end face of the base facing the wear-resistant plate, and the end face of the pump housing away from the oil chamber abuts against the bottom of the stepped groove.

7. The submersible sewage pump according to claim 1, characterized in that, The oil chamber housing is provided with a mechanical seal assembly, which is sleeved on the outer periphery of the main shaft; wherein, the mechanical seal assembly includes a rotating ring and a stationary ring, the rotating ring is connected to the main shaft and can rotate synchronously with the main shaft, the stationary ring is connected to the oil chamber housing and remains stationary, and the rotating ring and the stationary ring are in contact to form a sealing surface.

8. The submersible sewage pump according to claim 1, characterized in that, The submersible sewage pump also includes an oil seal skeleton, which is sleeved on the outer periphery of the main shaft and located inside the oil chamber shell and close to the pump shell. The outer peripheral wall of the oil seal skeleton is tightly fitted with the inner wall of the oil chamber shell to form a sealed space inside the oil chamber shell.

9. The submersible sewage pump according to claim 8, characterized in that, The outer peripheral wall of the oil seal skeleton extends with a lip, and an abutment portion is provided inside the oil chamber shell and on the side near the pump shell; when the oil seal skeleton is fitted onto the main shaft, the lip and the lower end face of the abutment portion are tightly fitted to prevent the lubricating oil in the oil chamber shell from leaking into the pump shell.

10. The submersible sewage pump according to claim 1, characterized in that, The pump casing has an outwardly extending outlet that communicates with the interior of the pump casing, so as to discharge the liquid pressurized by the impeller out of the pump casing.

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