Submersible mixer

Abstract

This invention provides a submersible mixer, which includes a motor, a shaft, and an impeller. The motor drives the impeller to rotate via the shaft. The motor housing is connected to the shaft via a mechanical seal. The submersible mixer further includes an intermediate ring seat arranged axially between the motor and the impeller on the shaft. The intermediate ring seat is fixed to the motor housing at its axial end near the motor, and at its axial end near the impeller, it cooperates with the impeller or the shaft to form a labyrinth seal, thereby forming a first sealing cavity between the intermediate ring seat and the motor housing. The first sealing cavity is sealed at both axial ends by the mechanical seal and the labyrinth seal.

Description

Technical Field

[0001] This invention relates to a submersible mixer. Background Technology

[0002] A submersible mixer is a device that can perform mixing and blending operations underwater. It consists of several parts such as a motor and an impeller. It is generally used in sewage treatment, for example, to mix sludge in sewage tanks and to make different water bodies achieve the flow rate required by the sewage treatment process, thus preventing sludge from settling.

[0003] Due to the need for long-term operation in wastewater, submersible mixers are designed with sealing requirements in mind to prevent damage from water or contaminants entering the equipment. For example, the national environmental protection industry standard HJ / T 279-2006 recommends that push-flow submersible mixers and their matching submersible motors should have sealing mechanisms and adopt bidirectional mechanical seals.

[0004] Currently known submersible mixers generally use one or two mechanical seals in front of the motor, with the second mechanical seal possibly immersed in grease to prevent water from entering the motor cavity. For example, Chinese patent document CN207478378U discloses a submersible mixer, which includes a housing, stator, rotor, front cover, rear cover, impeller, main shaft, first mechanical seal, and second mechanical seal.

[0005] However, certain contaminants in wastewater, especially long fibers such as hair, can adversely affect the use of mechanical seals, potentially entangle them and causing the first layer of mechanical seals to fail.

[0006] Chinese patent document CN204447882U discloses an anti-winding submersible mixer. The anti-winding functional structure of the submersible mixer consists of an impeller clamping ring, an impeller, a drive shaft, a mechanical seal, and a mechanical seal seat. The sealing ring on the impeller and the mechanical seal seat cooperate to form a labyrinth-type sealing structure, which is clearance-fitted in both the radial and axial directions, preventing entangled materials from entering the cavity where the mechanical seal is located.

[0007] Chinese patent document CN205340620U discloses a submersible mixer that prevents sand and entanglement, wherein an isolation body is provided outside the mechanical seal, the isolation body includes a filter screen surrounding the mechanical seal, and the bottom of the isolation body forms a labyrinth fit with the mechanical seal seat. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a more effective seal for submersible mixers.

[0009] To address this, the present invention provides a submersible mixer comprising a motor, a shaft, and an impeller. The motor drives the impeller to rotate via the shaft. The motor housing is connected to the shaft via a mechanical seal. The submersible mixer further comprises an intermediate ring seat axially arranged between the motor and the impeller on the shaft. The intermediate ring seat is fixed to the motor housing at its axial end near the motor, and at its axial end near the impeller, it cooperates with the impeller or the shaft to form a labyrinth seal, thereby forming a first sealing cavity between the intermediate ring seat and the motor housing. The first sealing cavity is sealed at both axial ends by the mechanical seal and the labyrinth seal.

[0010] In this way, the labyrinth seal effectively blocks external media containing contaminants, making it more difficult for contaminants to reach the mechanical seal. The mechanical seal is thus protected and can operate in a relatively clean media environment, reducing or eliminating the possibility of failure. Therefore, the sealing performance of the submersible mixer is improved. In practice, two mechanical seals are usually arranged. The first sealing cavity, formed by the labyrinth seal and the intermediate ring seat, isolates the external media through the labyrinth seal.

[0011] Preferably, the labyrinth seal extends parallel to the machine shaft axially. Therefore, whether mating with the impeller or the machine shaft, the intermediate ring seat forms a labyrinth seal with the impeller or machine shaft in an embracing or being embraced posture. When the labyrinth seal is formed by the intermediate ring seat at the axial end near the impeller and the outer periphery of the impeller hub, the first sealing cavity is jointly enclosed by the fixedly connected motor housing and intermediate ring seat, the mechanical seal closest to the impeller, the impeller hub, and the labyrinth seal between the intermediate ring seat and the impeller hub. When the labyrinth seal is formed by the intermediate ring seat at the axial end near the impeller and the machine shaft, the first sealing cavity is jointly enclosed by the fixedly connected motor housing and intermediate ring seat, the mechanical seal closest to the impeller, the intermediate ring seat, and the labyrinth seal between the intermediate ring seat and the machine shaft.

[0012] According to a preferred embodiment of the invention, the impeller hub has an opening on the motor side surrounding the shaft and facing the motor side, forming a recess. A labyrinth seal is formed by an intermediate ring seat engaging with the radially outer or radially inner circumferential wall of the recess at the axial end near the impeller. When the labyrinth seal is formed by the intermediate ring seat engaging with the radially outer circumferential wall of the recess at the axial end near the impeller, the first sealing cavity is jointly enclosed by the fixedly connected motor housing and intermediate ring seat, the mechanical seal closest to the impeller, the impeller hub, and the labyrinth seal between the intermediate ring seat and the radially outer circumferential wall of the recess. When the labyrinth seal is formed by the intermediate ring seat engaging with the radially inner circumferential wall of the recess at the axial end near the impeller, the first sealing cavity is jointly enclosed by the fixedly connected motor housing and intermediate ring seat, the mechanical seal closest to the impeller, the impeller hub, and the labyrinth seal between the intermediate ring seat and the radially inner circumferential wall of the recess. In both cases, the recess becomes part of the first sealing cavity.

[0013] Furthermore, the labyrinth seal can also be formed by the intermediate ring seat engaging with at least two of the following locations near the axial end of the impeller: the outer periphery of the impeller hub, the radial outer peripheral wall of the cavity, the radial inner peripheral wall of the cavity, and the machine shaft. If the intermediate ring seat engages with the radial inner peripheral wall of the cavity or the machine shaft in an embracing posture to form a first labyrinth seal and with the outer periphery of the impeller hub or the radial outer peripheral wall of the cavity to form a second labyrinth seal, then the intermediate ring seat, together with the motor housing and the impeller hub, respectively, forms a first labyrinth sealing cavity and a second labyrinth sealing cavity. The external medium must first pass through the second labyrinth seal to enter the second labyrinth sealing cavity, and then through the first labyrinth seal to enter the first labyrinth sealing cavity before reaching the position of the outermost mechanical seal.

[0014] Optionally, the labyrinth seal grooves for forming the labyrinth seal can be disposed on the intermediate ring seat and / or the impeller and / or the shaft. In the case of one or more labyrinth seals, all labyrinth seal grooves can be formed by the intermediate ring seat, or only some labyrinth seal grooves can be formed on the intermediate ring seat, while the remaining labyrinth seal grooves are formed by the outer periphery of the mating impeller hub, the radial outer peripheral wall of the cavity, the radial inner peripheral wall of the cavity, and the shaft. However, it is preferred that the labyrinth seal grooves include threaded grooves with a thread direction opposite to the impeller's rotation direction. The reversed threaded grooves make it more difficult for external media to enter the sealing cavity when the impeller rotates, thus further preventing contaminants in the external media from passing through the labyrinth seal. Here, for each labyrinth seal, only some labyrinth seal grooves may have threaded grooves with a thread direction opposite to the impeller's rotation direction; in the case of more than one labyrinth seal, only some labyrinth seal grooves may have threaded grooves with a thread direction opposite to the impeller's rotation direction.

[0015] The labyrinth seal consists of a first labyrinth seal formed by the intermediate ring seat engaging with one of the outer periphery of the impeller hub and the radial outer peripheral wall of the cavity at the axial end near the impeller, and a second labyrinth seal formed by the intermediate ring seat engaging with one of the radial inner peripheral wall of the cavity and the machine shaft at the axial end near the impeller. The first labyrinth seal is closer to the motor side in the axial direction of the machine shaft than the second labyrinth seal. Attached Figure Description

[0016] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings: Figure 1 This is a cross-sectional view of a submersible mixer according to an embodiment of the present invention; Figure 2 yes Figure 1 A partial cross-sectional view of the submersible mixer shown.

[0017] In the accompanying drawings, for clarity, identical or functionally similar parts are indicated by the same reference numerals. Detailed Implementation

[0018] Figure 1 A submersible mixer 100 according to the present invention is schematically shown in cross-sectional view. The submersible mixer 100 includes a motor 1, a shaft 10, and an impeller 3, wherein the motor 1 is capable of driving the impeller 3 to rotate via the shaft 10. The motor 1 is preferably a closed device, with only the shaft 10 extending from the housing of the motor 1. In the illustrated embodiment, the motor 1 has, for example, a cylindrical housing 11, the ends of which may be integral, but may also be made of, for example, a cylindrical housing 11. Figure 1 The sealing cover 41 shown is closed. The motor 1 can be any known submersible motor. The shaft 10 is the motor shaft of the motor 1; in other alternative embodiments, the shaft 10 may also include a motor shaft portion and an additional shaft portion connected by a coupling. The impeller 3 is mounted at the end of the shaft 10. The impeller 3 includes blades 30 and a hub body 31 that carries the blades 30. Preferably, the design of the impeller 3 is particularly suitable for applications in submersible mixers; for example, the hub body 31 has an opening on the motor side surrounding the shaft 10 and facing the motor side, particularly a hemispherical shape. The hub body 31, due to its shape, acts as a kind of shield, to some extent preventing contaminants in sewage from directly intruding behind the impeller 3. Additionally, the impeller 3 or the hub body 31 may have a bushing portion 32 that engages with the shaft 10 to facilitate the mounting and fixation of the impeller 3 on the shaft 10. In this embodiment, the bushing portion 32 simultaneously forms the radial inner peripheral wall of the aforementioned cavity, but the present invention is not limited thereto. The inner peripheral wall of the cavity can also be formed separately, in which case it is arranged on the radial outer side of the bushing portion 32.

[0019] like Figure 1As shown, the submersible mixer 100 also includes a series mechanical seal 4 and a mechanical seal 5 mounted on the shaft 10 and arranged between the motor 1 and the impeller 3. Mechanical seal 4 is the outermost mechanical seal relative to the motor 1, and there are no other mechanical seals between mechanical seal 4 and the impeller 3; mechanical seal 5 is located between the motor 1 and mechanical seal 4. Mechanical seal 5 is sealed within an inner sealing cavity 50 by mechanical seal 4. Preferably, the inner sealing cavity 50 is an oil chamber, in which mechanical seal 5 is immersed in clean lubricating oil, which further enhances the sealing performance.

[0020] As shown in the figure, the submersible mixer 100 also includes a sealing cover 41 for the mechanical seal 4, to which the mechanical seal 4 is coupled. The sealing cover 41 encloses the motor 1 at its output end, for example, by engaging the housing 11 of the motor 1 at its periphery. The sealing cover 41 is, for example, a disc-shaped object with a central opening. Specifically, the sealing cover 41 is a base for the mechanical seal 4 and an end cap for the motor 1.

[0021] According to the present invention, as shown in the figure, the submersible mixer 100 further includes an intermediate ring seat 2 that cooperates with the impeller 3 to form a first labyrinth seal 6 and a second labyrinth seal 7. The intermediate ring seat 2 and the sealing seat cover 41 form a first sealing cavity 8, and on the other side, it forms a second sealing cavity 9 with the hub body of the impeller 3. The first sealing cavity 8 is sealed relative to the second sealing cavity 9 by the second labyrinth seal 7, and the second sealing cavity 9 is sealed relative to the external environment by the first labyrinth seal 6. The intermediate ring seat 2 serves as a stationary element for the first and second labyrinth seals. In this way, at least two labyrinth seals effectively prevent contaminants in the external medium from reaching the mechanical seal 4, improving the working environment of the mechanical seal 4 and increasing its service life. At the same time, as long as the mechanical seal 4 has not failed, the normal working environment of the internal second-stage mechanical seal 5, especially in the oil chamber, can also be guaranteed.

[0022] In this embodiment, the intermediate ring seat 2, in an embracing or being embraced posture, that is, extending approximately parallel to the machine shaft axial direction, cooperates with the outer periphery of the impeller 3 hub body to form a first labyrinth seal 6, and cooperates with the radial inner peripheral wall of the cavity of the impeller 3 to form a second labyrinth seal 7.

[0023] like Figure 2 The intermediate ring seat 2 shown has a first annular mating part 21. The first annular mating part 21 can be designed according to the shape and size of the hub body 31 of the impeller 3 (or vice versa). Thus, the first annular mating part 21 of the intermediate ring seat 2 can surround the outer periphery of the hub body 31 in the assembled state. Furthermore, a labyrinth sealing groove is constructed on the inner periphery of the first annular mating part 21 and / or the outer periphery of the hub body 31, so that a first labyrinth seal 6 can be formed.

[0024] Alternatively, although not shown, another form of the first annular mating part can be constructed, which is surrounded by the hub body 31 of the impeller 3 in the assembled state, that is, the first labyrinth seal is formed at the radial outer peripheral wall of the cavity; obviously, although not shown, another annular mating part can also be constructed at the same time, surrounding the hub body 31 of the impeller 3, that is, the first labyrinth seal is provided at both the outer peripheral wall of the impeller hub body 31 and the radial outer peripheral wall of the cavity.

[0025] In other embodiments, although not illustrated, the intermediate ring seat 2 and the impeller 3 are constructed and fitted in other forms, for example, not in an encircling or being encircled posture, but in some kind of insertion fit, which can still form a first labyrinth seal at the fit.

[0026] The intermediate ring seat 2 extends from the first annular mating portion 21 toward the motor side via its first wall 23, sealingly connecting with the motor housing or sealing cover. On the other side, it extends to the second annular mating portion 22 via its second wall 24. The second annular mating portion 22, in a wrapping manner, mates with the inner peripheral wall of the cavity to form a labyrinth seal 7. The second annular mating portion 22 can be designed according to the shape and size of the inner peripheral wall of the impeller 3's cavity or the bushing portion 32 (or vice versa), so that the second annular mating portion 22 of the intermediate ring seat 2 can wrap around the inner peripheral wall of the cavity or the bushing portion 32 in the assembled state. Furthermore, a labyrinth sealing groove is constructed on the inner periphery of the second annular mating portion 22 and / or the inner peripheral wall of the cavity or the bushing portion 32, thus enabling the formation of the second labyrinth seal 7. Additionally, for the intermediate ring seat 2, the radial direction of the second annular mating portion 22 is an axial opening.

[0027] Obviously, although not shown, the intermediate ring seat 2 can also be arranged in an embracing posture to cooperate with the machine shaft 10 to form a second labyrinth seal in the aforementioned sense, with a specific construction method similar to the second labyrinth seal 7 shown in the figure. Alternatively, although not shown, the intermediate ring seat 2 can simultaneously form a second labyrinth seal with the inner peripheral wall of the cavity of the machine shaft 10 and the impeller 3 or the bushing portion 32, with a specific construction method similar to the second labyrinth seal 7 shown in the figure.

[0028] In some embodiments, as shown in the figure, the second wall 24 between the first annular mating portion 21 and the second annular mating portion 22 is recessed towards the motor side to form an annular recess 23. Therefore, the flow of the medium containing contaminants is advantageously hindered and guided, thereby consuming kinetic energy.

[0029] As shown in the figure, viewed along the axial direction of the machine shaft 1, the first labyrinth seal 6 is positioned closer to the motor side than the second labyrinth seal 7. This is particularly advantageous when the first labyrinth seal 6 is formed by the intermediate ring seat 2 embracing the impeller 3, because it forces contaminants entering the first sealing cavity 8 through the first labyrinth seal 6 to change their direction of travel in order to reach the second labyrinth seal 7. This process consumes more of the contaminants' kinetic energy, thus increasing the difficulty for the contaminants to pass through the second labyrinth seal 7.

[0030] In some embodiments, the labyrinth seal grooves for forming the first labyrinth seal 6 and / or the second labyrinth seal 7 include threaded grooves with a thread direction opposite to the rotation direction of the impeller 3. Such reverse threaded grooves can prevent impurities from entering the sealing cavity, thereby greatly reducing the amount of contaminants passing through the respective labyrinth seals.

[0031] Although some embodiments of the invention have been shown and described, those skilled in the art will understand that various combinations, variations, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0032] List of reference numerals 100 Submersible Mixer 1. Motor 10 machine shafts 11 Motor housing 2. Intermediate ring seat 21 First Annular Mating Part 22 Second Annular Mating Part 23 First Wall 24 Second Wall 3 Impeller 30 blades 31 Wheel hub body 32. Bushing section 4 Mechanical seal 41 Sealing seat cover 5 Mechanical seal 50 Inner sealing cavity 6. First Maze Sealing 7. The Second Maze Seal 8 First sealing cavity 9. Second sealing cavity.

Claims

1. A submersible mixer, comprising a motor, a shaft (10), and an impeller (3), wherein the motor is capable of driving the impeller (3) to rotate via the shaft (10), and the housing of the motor is connected to the shaft (10) via a mechanical seal, characterized in that, The submersible mixer further includes an intermediate ring seat (2) arranged axially between the motor and the impeller (3) on the shaft. The intermediate ring seat is fixed to the motor housing at the axial end near the motor, and at the axial end near the impeller (3) it cooperates with the impeller (3) to form a first labyrinth seal (6) and cooperates with the impeller (3) and / or the shaft (10) to form a second labyrinth seal (7). This forms a first sealing cavity (8) between the intermediate ring seat (2) and the motor housing, and a second sealing cavity (9) between the intermediate ring seat (2) and the hub of the impeller (3). The first sealing cavity (8) is sealed relative to the second sealing cavity (9) by the second labyrinth seal (7), and the second sealing cavity (9) is sealed relative to the external environment by the first labyrinth seal (6). The first sealing cavity (8) is sealed at both axial ends by the mechanical seal and the second labyrinth seal (7).

2. The submersible mixer according to claim 1, characterized in that, The first labyrinth seal (6) and the second labyrinth seal (7) extend parallel to the machine shaft axial direction.

3. The submersible mixer according to claim 1 or 2, characterized in that, The first labyrinth seal is formed by the intermediate ring seat (2) engaging with the outer periphery of the hub of the impeller (3) at the axial end near the impeller (3), and the second labyrinth seal (7) is formed by the intermediate ring seat (2) engaging with the machine shaft (10) at the axial end near the impeller (3).

4. The submersible mixer according to claim 1 or 2, characterized in that, The impeller (3) has a hub body with an opening on the motor side surrounding the shaft (10) and facing the motor side.

5. The submersible mixer according to claim 4, characterized in that, The first labyrinth seal (6) is formed by the intermediate ring seat (2) engaging with the outer periphery of the hub body of the impeller (3) and / or the radial outer peripheral wall of the cavity at the axial end near the impeller (3).

6. The submersible mixer according to claim 5, characterized in that, The second labyrinth seal (7) is formed by the intermediate ring seat (2) engaging with the radial inner circumferential wall of the cavity and / or the machine shaft at the axial end near the impeller (3).

7. The submersible mixer according to claim 4, characterized in that, The first labyrinth seal (6) is closer to the motor side in the axial direction of the machine shaft than the second labyrinth seal (7).

8. The submersible mixer according to claim 1, characterized in that, The labyrinth sealing groove of the first labyrinth seal and / or the second labyrinth seal is disposed on the intermediate ring seat (2) and / or the impeller (3) and / or the shaft (10), and the labyrinth sealing groove includes a thread groove with a thread direction opposite to the rotation direction of the impeller (3).

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