Submersible mixer

Abstract

The invention provides a submersible mixer which comprises a motor, a motor shaft and an impeller, the motor can drive the impeller to rotate through the motor shaft, and a shell of the motor is connected with the motor shaft through a mechanical seal. The submersible mixer further comprises a middle ring seat which is arranged between the motor and the impeller in the axial direction of the crankshaft, the middle ring seat is fixed to a shell of the motor at the position close to the axial end of the motor, and the middle ring seat is matched with the impeller or the crankshaft at the position close to the axial end of the impeller to form labyrinth seal. A first sealing cavity is formed between the middle ring seat and a shell of the motor, and the two axial ends of the first sealing cavity are sealed through the mechanical seal and the labyrinth seal respectively.

Description

Technical Field

[0001] The invention relates to a submersible mixer. Background Art

[0002] A submersible mixer is a device that can perform stirring and mixing operations underwater. It consists of several parts such as a motor and an impeller. It can generally be used for sewage treatment, such as stirring and mixing the sludge in a sewage pool, and allowing different water bodies to obtain the flow rate required by the sewage treatment process to prevent sludge sedimentation.

[0003] Due to the need to work in sewage for a long time, in order to prevent water or dirt from entering the equipment and causing damage, the submersible mixer has certain requirements for sealing in design. For example, the national environmental protection industry standard HJ / T 279-2006 recommends that the plug-flow submersible mixer and its matching submersible motor should have a sealing mechanism and use a bidirectional mechanical seal.

[0004] Currently known submersible mixers generally use one or two mechanical seals in front of the motor, wherein the second mechanical seal may be 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, a stator, a rotor, a front cover, a rear cover, an impeller, a main shaft, a first mechanical seal and a second mechanical seal.

[0005] However, certain impurities in sewage, especially long fibers such as hair, will have an adverse effect on the use of mechanical seals, and may entangle the mechanical seals, causing the first mechanical seal to fail.

[0006] Chinese patent document CN204447882U discloses an anti-winding submersible mixer, the anti-winding functional structure of the submersible mixer is composed of an impeller clamping ring, an impeller, a transmission shaft, a mechanical seal and a mechanical seal seat, wherein the sealing ring on the impeller and the mechanical seal seat cooperate to form a labyrinth seal structure, which is a clearance fit in both the radial and axial directions, so that winding objects outside the main engine cannot enter the cavity where the mechanical seal is located.

[0007] Chinese patent document CN205340620U discloses a sand-proof and anti-winding submersible mixer, in which an isolating body is arranged outside the mechanical seal, the isolating body includes a filter screen surrounding the mechanical seal, and the bottom of the isolating 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 a submersible mixer.

[0009] To this end, the present invention provides a submersible mixer, which includes a motor, a shaft and an impeller. The motor can drive the impeller to rotate through the shaft, and the housing of the motor is connected to the shaft through a mechanical seal. The submersible mixer also includes an intermediate ring seat arranged between the motor and the impeller in the axial direction of the shaft, the intermediate ring seat is fixed to the housing of the motor at the axial end close to the motor, and cooperates with the impeller or the shaft to form a labyrinth seal at the axial end close to the impeller, so that a first sealing cavity is formed between the intermediate ring seat and the housing of the motor, and the first sealing cavity is closed at both axial ends by the mechanical seal and the labyrinth seal respectively.

[0010] In this way, the external medium containing dirt will be effectively blocked by the labyrinth seal, so it is more difficult for dirt to reach the mechanical seal. The mechanical seal is therefore protected and operates in a relatively clean medium environment, avoiding or reducing the possibility of failure. Therefore, the sealing of the submersible mixer is improved. In practice, two mechanical seals are usually arranged, and the first sealing chamber enclosed by the labyrinth seal and the intermediate ring seat isolates the external medium through the above-mentioned labyrinth seal.

[0011] Preferably, the labyrinth seal extends parallel to the axial direction of the machine shaft. Therefore, no matter it cooperates with the impeller or the machine shaft, the intermediate ring seat cooperates with the impeller or the machine shaft in an embracing or being embraced posture to form a labyrinth seal. In the case where the labyrinth seal is formed by the intermediate ring seat at the axial end near the impeller and the outer periphery of the hub body of the impeller, the first sealing chamber is surrounded by the fixedly connected motor housing and the intermediate ring seat, the mechanical seal closest to the impeller, the hub body of the impeller, and the labyrinth seal between the intermediate ring seat and the hub body of the impeller. In the case where the labyrinth seal is formed by the intermediate ring seat at the axial end near the impeller and the machine shaft to form a labyrinth seal, the first sealing chamber is surrounded by the fixedly connected motor housing and the 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 present invention, the hub body of the impeller has a concave cavity with an opening surrounding the shaft and facing the motor side on the motor side. The labyrinth seal is formed by the intermediate ring seat at the axial end near the impeller and the radial outer peripheral wall or radial inner peripheral wall of the concave cavity. In the case where the labyrinth seal is formed by the intermediate ring seat at the axial end near the impeller and the radial outer peripheral wall of the concave cavity, the first sealed cavity is surrounded by the fixed motor housing and the intermediate ring seat, the mechanical seal closest to the impeller, the hub body of the impeller, and the labyrinth seal between the intermediate ring seat and the radial outer peripheral wall of the concave cavity. In the case where the labyrinth seal is formed by the intermediate ring seat at the axial end near the impeller and the radial inner peripheral wall of the concave cavity, the first sealed cavity is surrounded by the fixed motor housing and the intermediate ring seat, the mechanical seal closest to the impeller, the hub body of the impeller, and the labyrinth seal between the intermediate ring seat and the radial inner peripheral wall of the concave cavity. In both cases, the concave cavity becomes a part of the first sealed cavity.

[0013] Furthermore, the labyrinth seal can also be formed by the intermediate ring seat cooperating with at least two of the outer periphery of the impeller hub body, the radial outer peripheral wall of the cavity, the radial inner peripheral wall of the cavity, and the shaft at the axial end near the impeller. If the intermediate ring seat cooperates with the radial inner peripheral wall of the cavity or the shaft in an embracing posture to form a first labyrinth seal and cooperates with the outer periphery of the impeller hub body or the radial outer peripheral wall of the cavity to form a second labyrinth seal, then the motor housing and the impeller hub body are respectively surrounded on both sides of the intermediate ring seat to form a first labyrinth seal cavity and a second labyrinth seal cavity. The external medium needs to first pass through the second labyrinth seal to enter the second labyrinth seal cavity, and then pass through the first labyrinth seal to enter the first labyrinth seal cavity before it can reach the position of the outermost mechanical seal.

[0014] Optionally, the labyrinth seal groove for forming the labyrinth seal can be arranged on the intermediate ring seat and / or on the impeller and / or on the shaft. In the case of one or more labyrinth seals, all the labyrinth seal grooves can be formed by the intermediate ring seat, or only part of the labyrinth seal grooves can be formed on the intermediate ring seat, and the remaining labyrinth seal grooves are formed by the outer periphery of the matching impeller hub body, 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 groove includes a thread groove whose thread direction is opposite to the rotation direction of the impeller. The reverse thread groove makes it more difficult for the external medium to enter the interior of the sealing cavity when the impeller rotates, so that the dirt in the external medium can be further prevented from passing through the labyrinth seal. Here, for each labyrinth seal, only part of the labyrinth seal grooves can have a thread groove whose thread direction is opposite to the rotation direction of the impeller; in the case of more than one labyrinth seal, only part of the labyrinth seal grooves can have a thread groove whose thread direction is opposite to the rotation direction of the impeller.

[0015] The labyrinth seal is composed of a first labyrinth seal formed by the intermediate ring seat cooperating with one of the outer periphery of the hub body of the impeller and the radial outer peripheral wall of the concave cavity near the axial end of the impeller, and a second labyrinth seal formed by the intermediate ring seat cooperating with one of the radial inner peripheral wall of the concave cavity and the machine shaft near the axial end of the impeller, wherein the first labyrinth seal is closer to the motor side in the axial direction of the machine shaft than the second labyrinth seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The implementation of the present invention is described in detail below in conjunction with the accompanying drawings. In the accompanying drawings:

[0017] Figure 1 is a cross-sectional view of a submersible mixer according to an embodiment of the present invention.

[0018] Figure 2 yes Figure 1 A partial cross-sectional view of the submersible mixer shown.

[0019] In the drawings, identical or functionally similar components are indicated by the same reference numbers for clarity. DETAILED DESCRIPTION

[0020] Figure 1 A submersible mixer 100 according to the present invention is schematically shown in a cross-sectional view. The submersible mixer 100 comprises 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 protruding from the housing of the motor 1. In the illustrated embodiment, the motor 1 has a housing 11, for example, in the form of a cylinder, the ends of which may be integral, but may also be formed by, for example, Figure 1 The sealing seat cover 41 shown is closed. The motor 1 may be any known submersible motor. The crankshaft 10 is the motor shaft of the motor 1. In other optional embodiments, the crankshaft 10 may also include a motor shaft portion and an additional shaft portion connected by a coupling. The impeller 3 is installed at the end of the crankshaft 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 application in a submersible mixer. For example, the hub body 31 has a concave cavity that is open around the crankshaft 10 and faces the motor side on the motor side, especially a hemispherical cover. The hub body 31 plays a role similar to a shield due to its shape, which to a certain extent prevents dirt in the sewage from directly invading the back of the impeller 3. In addition, the impeller 3 or the hub body 31 may have a sleeve portion 32 that matches the crankshaft 10, so that the impeller 3 can be installed and fixed on the crankshaft 10. In this embodiment, the sleeve portion 32 also forms the radial inner circumferential wall of the concave cavity, but the present invention is not limited thereto. The inner circumferential wall of the concave cavity may also be formed separately and arranged radially outside the sleeve portion 32 .

[0021] like Figure 1As shown, the submersible mixer 100 further includes a mechanical seal 4 and a mechanical seal 5 arranged in series between the motor 1 and the impeller 3 and mounted on the shaft 10. The mechanical seal 4 is the outermost mechanical seal relative to the motor 1, and there is no other mechanical seal between the mechanical seal 4 and the impeller 3; the mechanical seal 5 is between the motor 1 and the mechanical seal 4. The mechanical seal 5 is sealed in the inner seal chamber 50 by the mechanical seal 4. Preferably, the inner seal chamber 50 is an oil chamber, and the mechanical seal 5 is immersed in clean lubricating oil, and the oil chamber additionally enhances the sealing performance.

[0022] As shown in the figure, the submersible mixer 100 further includes a sealing seat cover 41 provided for the mechanical seal 4, and the mechanical seal 4 is coupled to the sealing seat cover 41. The sealing seat cover 41 closes the motor 1 at the output end of the motor 1, for example, the periphery of the sealing seat cover 41 engages the housing 11 of the motor 1. The sealing seat cover 41 is, for example, a disc-shaped object with a hole in the middle. In particular, the sealing seat cover 41 is a base for the mechanical seal 4 and an end cover for the motor 1.

[0023] According to the present invention, as shown in the figure, the submersible mixer 100 also includes an intermediate ring seat 2 that cooperates with the impeller 3 to form a labyrinth seal 6 and a labyrinth seal 7. The intermediate ring seat 2 and the seal seat cover 41 enclose a first sealing chamber 8, and on the other side, enclose a second sealing chamber 9 with the hub body of the impeller 3. The first sealing chamber 8 is sealed relative to the second sealing chamber 9 by the labyrinth seal 7, and the second sealing chamber 9 is sealed relative to the external environment by the labyrinth seal 6. The intermediate ring seat 2 is used as a stationary part of the labyrinth seal. In this way, at least two labyrinth seals effectively prevent dirt in the external medium from reaching the mechanical seal 4, improve the working environment of the mechanical seal 4, and increase the service life of the mechanical seal 4. 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.

[0024] In this embodiment, the intermediate ring seat 2 cooperates with the outer periphery of the hub body of the impeller 3 in an embracing or embraced posture, that is, extending approximately parallel to the axial direction of the machine shaft to form a labyrinth seal 6, and cooperates with the radial inner peripheral wall of the concave cavity of the impeller 3 to form a labyrinth seal 7.

[0025] like Figure 2 The intermediate ring seat 2 shown is constructed with a first annular fitting portion 21, which can be designed according to the shape and size of the hub body 31 of the impeller 3 (or vice versa), so that the first annular fitting portion 21 of the intermediate ring seat 2 can embrace the outer periphery of the hub body 31 in the assembled state, and a labyrinth sealing groove is constructed on the inner periphery of the first annular fitting portion 21 and / or the outer periphery of the hub body 31, so that a labyrinth seal 6 can be formed in cooperation.

[0026] Alternatively, although not shown in the figure, another form of the first annular fitting portion may be constructed, which is surrounded by the hub body 31 of the impeller 3 on the inner periphery when assembled, that is, cooperates to form the above-mentioned labyrinth seal at the radial outer peripheral wall of the concave cavity; obviously, although not shown in the figure, another annular fitting portion surrounding the outer periphery of the hub body 31 of the impeller 3 may be constructed at the same time, that is, the above-mentioned labyrinth seal is simultaneously provided at the outer periphery of the impeller hub body 31 and the radial outer peripheral wall of the concave cavity.

[0027] In some other embodiments, although not shown in the figure, the intermediate ring seat 2 and the impeller 3 are constructed and matched in other forms, for example, not in an embracing or being embraced posture, but in some kind of insertion fit, and the first labyrinth seal can still be constructed at the fitting position.

[0028] The intermediate ring seat 2 extends from the first annular matching portion 21 to the motor side through its first wall 23, and is sealed and connected to the motor housing or the sealing cover plate. The other side extends to the second annular matching portion 22 through the second wall 24. The second annular matching portion 22 cooperates with the inner circumferential wall of the cavity in an embracing manner to form a labyrinth seal 7. The second annular matching portion 22 can be designed according to the shape and size of the inner circumferential wall of the cavity of the impeller 3 or the shaft sleeve portion 32 (or vice versa), so that the second annular matching portion 22 of the intermediate ring seat 2 can embrace the inner circumferential wall of the cavity or the shaft sleeve portion 32 in the assembled state, and a labyrinth seal groove is constructed on the inner circumference of the second annular matching portion 22 and / or the inner circumferential wall of the cavity or the shaft sleeve portion 32, so that the second labyrinth seal 7 can be formed in cooperation. In addition, for the intermediate ring seat 2, the radial inside of the second annular matching portion 22 is an axial opening.

[0029] Obviously, although not shown in the figure, the intermediate ring seat 2 can also cooperate with the machine shaft 10 in an embracing posture to form the second labyrinth seal in the aforementioned sense, and the specific construction method is similar to the second labyrinth seal 7 shown in the figure. Alternatively, although not shown in the figure, the intermediate ring seat 2 can simultaneously form a labyrinth seal with the machine shaft 10 and the inner peripheral wall of the concave cavity of the impeller 3 or the shaft sleeve portion 32, and the specific construction method is similar to the second labyrinth seal 7 shown in the figure.

[0030] In some embodiments, as shown in the figure, the second wall 24 between the first annular fitting portion 21 and the second annular fitting portion 22 is recessed toward the motor side to form an annular recess 23. Therefore, the flow of the medium containing dirt is advantageously hindered and guided to consume kinetic energy.

[0031] As shown in the figure, from the axial direction of the machine shaft 1, the position of the labyrinth seal 6 is closer to the motor side than the labyrinth seal 7. This is particularly advantageous when the labyrinth seal 6 is formed by the intermediate ring seat 2 and the impeller 3 in an embracing posture, because the dirt entering the first sealing chamber 8 through the labyrinth seal 6 must change its direction of travel before it can reach the labyrinth seal 7, and in this process, more kinetic energy of the dirt is consumed, thereby increasing the difficulty of the dirt passing through the second labyrinth seal 7.

[0032] In some embodiments, the labyrinth seal grooves used to form the labyrinth seal 6 and / or the labyrinth seal 7 include thread grooves having a thread direction opposite to the rotation direction of the impeller 3. Such reverse thread grooves can prevent impurities from entering the sealing cavity, thereby greatly reducing the dirt passing through the corresponding labyrinth seals.

[0033] Although some embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various combinations, changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0034] Reference numerals list 100 Submersible mixer 1 Motor 10 Crankshaft 11 Motor housing 2 Intermediate ring seat 21 first annular mating portion 22 second annular fitting portion 23 First Wall 24 Second Wall 3 Impeller 30 blades 31 Hub body 32 Bushing 4 Mechanical seal 41 Sealing seat cover 5 Mechanical seal 50 Inner sealing chamber 6 Labyrinth seal 7 Labyrinth seal 8 First sealing chamber 9 Second sealed chamber.

Claims

1. A submersible mixer, comprising a motor, a shaft and an impeller, wherein the motor can drive the impeller to rotate through the shaft, and the housing of the motor is connected to the shaft through a mechanical seal, wherein: The submersible mixer also includes an intermediate ring seat arranged between the motor and the impeller in the axial direction of the machine shaft. The intermediate ring seat is fixed to the housing of the motor at the axial end close to the motor, and cooperates with the impeller or the machine shaft to form a labyrinth seal at the axial end close to the impeller, so that a first sealing cavity is formed between the intermediate ring seat and the housing of the motor, and the first sealing cavity is closed at both axial ends by the mechanical seal and the labyrinth seal respectively.

2. The submersible mixer according to claim 1, characterized in that: The labyrinth seal extends parallel to the axial direction of the crankshaft.

3. The submersible mixer according to claim 1 or 2, characterized in that: The labyrinth seal is formed by the intermediate ring seat cooperating with the outer periphery of the hub body of the impeller or the shaft near the axial end of the impeller.

4. The submersible mixer according to claim 1 or 2, characterized in that: The hub body of the impeller has a recessed cavity on the motor side, the recessed cavity surrounding the machine shaft and facing the motor side.

5. The submersible mixer according to claim 4, characterized in that: The labyrinth seal is formed by the cooperation between the intermediate ring seat and the radial outer peripheral wall or the radial inner peripheral wall of the concave cavity at the axial end close to the impeller.

6. The submersible mixer according to claim 4, characterized in that: The labyrinth seal is formed by the intermediate ring seat cooperating with at least two of the outer periphery of the hub body of the impeller, the radial outer peripheral wall of the cavity, the radial inner peripheral wall of the cavity, and the machine shaft at the axial end near the impeller.

7. The submersible mixer according to claim 1, characterized in that: The labyrinth seal groove of the labyrinth seal is arranged on the intermediate ring seat and / or the impeller and / or the machine shaft, and the labyrinth seal groove includes a thread groove whose thread direction is opposite to the rotation direction of the impeller.

8. The submersible mixer according to claim 6, characterized in that: The labyrinth seal is composed of a first labyrinth seal formed by the intermediate ring seat cooperating with one of the outer periphery of the hub body of the impeller and the radial outer peripheral wall of the concave cavity near the axial end of the impeller, and a second labyrinth seal formed by the intermediate ring seat cooperating with one of the radial inner peripheral wall of the concave cavity and the machine shaft near the axial end of the impeller, wherein the first labyrinth seal is closer to the motor side in the axial direction of the machine shaft than the second labyrinth seal.

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