JP2018131944A - Multistage centrifugal pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multistage centrifugal pump that can use a general-purpose shaft seal device seal and that can generate high-pressure liquid.SOLUTION: A multistage centrifugal pump comprises a first rotating shaft 11 and a second rotating shaft 12 arranged in parallel, a first centrifugal impeller 15 fixed to the first rotating shaft 11, a second centrifugal impeller 16 fixed to the second rotating shaft 12, a first casing 18 that houses the first centrifugal impeller 15, a second casing 19 that houses the second centrifugal impeller 16, a communicating flow passage 22 that connects the first casing 18 and the second casing 19, and a single multishaft motor 24 that synchronously rotates the first rotating shaft 11 and the second rotating shaft 12 in opposite directions. The first centrifugal impeller 15 faces the multishaft motor 24, and the second centrifugal impeller 16 faces in a direction opposite to the first centrifugal impeller 15.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multistage centrifugal pump device for transferring a liquid.

  As shown in FIG. 7, the multistage centrifugal pump device includes a plurality of centrifugal impellers 202 fixed to the rotary shaft 201 and an electric motor 203 connected to the rotary shaft 201. The impeller 202 is disposed in the casing 206, and a suction port 206 a and a discharge port 206 b are provided at the end of the casing 206. When the impeller 202 is rotated by the electric motor 203, the liquid is guided into the casing 206 through the suction port 206a, pressurized by the plural stages of impellers 202, and discharged outside through the discharge port 206b. Such a multistage centrifugal pump device is widely used as a device for transferring a liquid.

  A mechanical seal 210 that is a shaft seal device is disposed between the impeller 202 and the electric motor 203. The mechanical seal 210 seals a gap between the casing 206 and the rotating shaft 201, and prevents high-pressure liquid pressurized by the impeller 202 from leaking from the casing 206.

  As the number of impellers 202 increases, the multistage centrifugal pump device can transfer liquid at a higher pressure. However, as the number of impellers 202 increases, the mechanical seal 210 needs to have a structure that can withstand higher pressure. In recent years, in particular, as a building becomes taller, a multistage centrifugal pump device capable of generating a higher pressure has been demanded. The mechanical seal 210 that can be used in such a multistage centrifugal pump device does not exist in a general-purpose product and is a custom-made product. For this reason, the cost of a pump apparatus rises. Furthermore, if many impellers 202 are fixed to the rotating shaft 201, the rotating shaft 201 becomes inevitably long and the rotating shaft 201 is easily bent.

JP 2007-205360 A Japanese Patent Laid-Open No. 2006-108951

  In order to solve the above problem, a pump system in which two multistage centrifugal pump devices 220A and 220B are connected in series as shown in FIG. 8 has been proposed. The discharge port of the first-stage multistage centrifugal pump device 220A is connected to the suction port of the second-stage multistage centrifugal pump device 220B via a connecting pipe 223. According to such an arrangement, the rotation shafts of the multistage centrifugal pump devices 220A and 220B can be shortened, so that bending of the rotation shafts can be prevented.

  However, since the first multistage centrifugal pump device and the second multistage centrifugal pump device are connected in series, a high pressure is still applied to the mechanical seal 210 of the second multistage centrifugal pump device. For this reason, the second-stage multistage centrifugal pump device needs to use a custom-made mechanical seal 210, which increases the manufacturing cost.

  Therefore, an object of the present invention is to provide a multistage centrifugal pump device that can use a general-purpose shaft seal device and can generate a high-pressure liquid.

  In order to achieve the above-described object, one aspect of the present invention provides a first rotating shaft and a second rotating shaft arranged in parallel, and at least one first centrifugal impeller fixed to the first rotating shaft. , At least one second centrifugal impeller fixed to the second rotating shaft, a first casing that houses the first centrifugal impeller, a second casing that houses the second centrifugal impeller, and the second A communication passage connecting one casing and the second casing; a single multi-axis motor that rotates the first rotating shaft and the second rotating shaft in synchronization in opposite directions; The vehicle is directed to the multi-shaft motor, and the second centrifugal impeller is directed in the opposite direction to the first centrifugal impeller.

In a preferred aspect of the present invention, the first shaft sealing device disposed between the first centrifugal impeller and the multi-shaft electric motor, and the second centrifugal impeller and the multi-shaft electric motor are disposed. A second shaft seal device is further provided.
In a preferred aspect of the present invention, the first shaft sealing device and the second shaft sealing device have the same configuration and the same size.
In a preferred aspect of the present invention, the multi-axis motor includes a plurality of rotors connected to the first rotating shaft and the second rotating shaft, to which permanent magnets are attached, and a plurality of electric machines disposed on the outer periphery of each rotor. A plurality of armatures each including a magnetic pole tooth and a coil attached to the magnetic pole tooth, and a permanent magnet provided on the adjacent rotor includes a magnetic cup between the permanent magnets via the armature. A plurality of pairs of different magnetic poles are formed so that they can be reversed by ringing, and when driving the adjacent rotors, energization is performed so that the armatures at symmetrical positions become different magnetic poles. It is configured to be magnetically coupled between different magnetic poles.

  According to the present invention, the pressure of the liquid pressurized by the second centrifugal impeller is not applied to the portion of the second casing through which the second rotating shaft passes. Therefore, for example, a general-purpose mechanical seal can be used as the shaft seal device attached to the second casing, and as a result, the cost of the entire pump device can be reduced. Furthermore, since the multi-shaft motor can rotate the first rotating shaft and the second rotating shaft in synchronization with each other without using a timing gear, vibration and noise during operation of the pump device can be reduced. Is possible.

It is sectional drawing which shows one Embodiment of the multistage centrifugal pump apparatus of this invention. It is the II-II sectional view taken on the line of FIG. It is explanatory drawing explaining operation | movement of the multi-axis motor shown in FIG.1 and FIG.2. It is a time chart of the electricity supply pattern to the coil at the time of the operation | movement shown in FIG. It is a circuit diagram which shows the electricity supply state to the coil at the time of the operation | movement shown in FIG. It is sectional drawing which shows other embodiment of the multistage centrifugal pump apparatus of this invention. It is sectional drawing which shows the prior art example of a multistage centrifugal pump apparatus. It is sectional drawing which shows another prior art example of a multistage centrifugal pump apparatus.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of the multistage centrifugal pump device of the present invention. The multistage centrifugal pump device is fixed to the first rotary shaft 11 and the second rotary shaft 12 arranged in parallel, the plurality of first centrifugal impellers 15 fixed to the first rotary shaft 11, and the second rotary shaft 12. The plurality of second centrifugal impellers 16, the first casing 18 that accommodates the plurality of first centrifugal impellers 15, the second casing 19 that accommodates the plurality of second centrifugal impellers 16, and the first casing 18 And a single multi-axis motor 24 that rotates the first rotating shaft 11 and the second rotating shaft 12 in synchronization with each other in the opposite directions. The plurality of first centrifugal impellers 15 face the multi-axis electric motor 24, and the plurality of second centrifugal impellers 16 face the opposite direction to the plurality of first centrifugal impellers 15. In the present embodiment, the number of first centrifugal impellers 15 and the number of second centrifugal impellers 16 are the same. In one embodiment, the number of first centrifugal impellers 15 and the number of second centrifugal impellers 16 may be different. Furthermore, in one embodiment, only one each of the first centrifugal impeller 15 and the second centrifugal impeller 16 may be provided.

  The first casing 18 has a suction port 18a at its end, and the second casing 19 has a discharge port 19a at its end. The suction port 18a and the discharge port 19a are located at the same height. It is also possible to configure the multistage centrifugal pump device shown in FIG. 1 as an in-line type multistage centrifugal pump device by attaching another suction port and a discharge port arranged coaxially to the suction port 18a and the discharge port 19a. is there.

  The first casing 18 and the second casing 19 are arranged in parallel and are separated from each other. The discharge side of the first casing 18 and the suction side of the second casing 19 are connected by a communication channel 22. The communication flow path 22 is composed of a curved pipe so as not to hinder the flow of liquid. The first centrifugal impeller 15 faces the multi-shaft electric motor 24, and the second centrifugal impeller 16 faces the opposite direction to the first centrifugal impeller 15. The direction toward the multi-axis motor 24 is a direction in which the liquid flows from the suction port 18a toward the multi-axis motor 24.

  The first mechanical seal 31 as the first shaft seal device is detachably attached to the discharge side of the first casing 18 and the first rotating shaft 11. The first mechanical seal 31 is disposed between the first centrifugal impeller 15 and the multi-axis motor 24. A gap between the first casing 18 and the first rotating shaft 11 is sealed with a first mechanical seal 31. The second mechanical seal 32 as the second shaft sealing device is detachably attached to the suction side of the second casing 19 and the second rotating shaft 12. The second mechanical seal 32 is disposed between the second centrifugal impeller 16 and the multi-axis motor 24. A gap between the second casing 19 and the second rotating shaft 12 is sealed with a second mechanical seal 32. In one embodiment, an oil seal, a gland packing, or a labyrinth seal may be used as the first shaft sealing device and the second shaft sealing device instead of the mechanical seal.

  The multi-axis motor 24 is composed of a brushless DC motor capable of rotating at least two rotating shafts in opposite directions in synchronization. In the present embodiment, the multi-axis motor 24 is configured to rotate the first rotating shaft 11 and the second rotating shaft 12 at the same speed in synchronization with opposite directions.

  When the multi-axis motor 24 rotates the first rotating shaft 11 and the second rotating shaft 12 in the opposite directions, the first centrifugal impeller 15 and the second centrifugal impeller 16 rotate in the opposite directions. As the first centrifugal impeller 15 and the second centrifugal impeller 16 rotate, the liquid flows into the first casing 18 through the suction port 18 a and is pressurized by the first centrifugal impeller 15. The pressurized liquid flows into the second casing 19 through the communication channel 22 and is pressurized by the second centrifugal impeller 16. The second centrifugal impeller 16 is disposed downstream of the first centrifugal impeller 15, and the first centrifugal impeller 15 and the second centrifugal impeller 16 are arranged in series. Accordingly, the liquid is pressurized by both the first centrifugal impeller 15 and the second centrifugal impeller 16 and becomes high pressure.

  The liquid that comes into contact with the first mechanical seal 31 and the second mechanical seal 32 is liquid that has been pressurized by the first centrifugal impeller 15 and that has not been pressurized by the second centrifugal impeller 16. In other words, the pressure of the liquid boosted by the second centrifugal impeller 16 does not act on the second mechanical seal 32. In this embodiment, since the number of the first centrifugal impeller 15 and the second centrifugal impeller 16 is the same, the pressure acting on the first mechanical seal 31 and the second mechanical seal 32 is the liquid discharged from the discharge port 19a. Is half of the pressure. Therefore, general-purpose mechanical seals can be used for the first mechanical seal 31 and the second mechanical seal 32. As a result, the cost of the entire multistage centrifugal pump device can be reduced.

  Since the discharge side of the first casing 18 and the suction side of the second casing 19 are connected by the communication flow path 22, the same pressure of the liquid acts on the first mechanical seal 31 and the second mechanical seal 32. Therefore, mechanical seals having the same configuration and the same size can be used for the first mechanical seal 31 and the second mechanical seal 32.

  The first rotating shaft 11 and the second rotating shaft 12 are connected to the rotors 2A and 2B of the common multi-axis motor 24 by a first shaft joint 35 and a second shaft joint 36, respectively. There is no timing gear between the rotary shafts 11 and 12 and the multi-axis motor 24, and the torque generated by the multi-axis motor 24 is directly transmitted to the first rotary shaft 11 and the second rotary shaft 12. Such a configuration using the multi-axis motor 24 can reduce vibration and noise during operation of the multistage centrifugal pump device.

  Next, an embodiment of the multi-axis motor 24 will be described. FIG. 1 shows a longitudinal section of the multi-axis motor 24. 2 is a sectional view taken along line II-II in FIG. A pair of rotors 2A and 2B are accommodated in the motor frame 1. Each rotor 2A, 2B is rotatably supported by bearings 5, 5 in the vicinity of both ends. The two rotors 2A and 2B are arranged such that magnetic fluxes are generated in the radial direction at equal intervals symmetrically about the axis of the permanent magnets 2a and 2b each having 2n poles (n is the number of poles). In this embodiment, each rotor 2A, 2B has n = 2, and 4-pole permanent magnets of S, N, S, N are attached to the respective rotors. These four permanent magnets are arranged at equal intervals around the central axis of each rotor. In the present embodiment, the permanent magnets are fixed to the outer peripheral surfaces of the respective rotors 2A and 2B. However, in one embodiment, the permanent magnets may be embedded in the respective rotors 2A and 2B.

A plurality of armatures 3a _{1 to} 3a ₆ and 3b _{1 to} 3b ₆ are arranged on the outer peripheral side of the rotors 2A and 2B so as to surround the entire outer periphery of each rotor 2A and 2B. The pitch between adjacent armatures is set to 60 °. Each of the armatures 3a _{1 to} 3a ₆ and 3b _{1 to} 3b ₆ includes a magnetic pole tooth U to Z and U _{1 to} Z ₁ formed on the armature core Ac, and a coil 4a attached to the magnetic pole teeth U to Z and U _{1 to} Z _1. , 4b. The magnetic pole teeth U to Z and U1 to Z1 are formed in a circumferentially equidistant manner, and the magnetic pole teeth U to Z and U1 to Z1 are symmetrical and opposite to the magnetic poles in the center plane C of the axis of the rotors 2A and 2B. The coils 4a and 4b are respectively mounted so that the coil 4b is wound oppositely to the coil 4a.

Next, the operation of the multi-axis motor 24 configured as described above will be described. FIG. 3 is an explanatory view for explaining the operation of the multi-axis motor 24. In FIG. 3, only the rotor and the armature are shown to simplify the illustration.
When the coils 4a and 4b of the armature are energized, a space moving magnetic field is formed in the armature to invert and rotate the rotors 2A and 2B. That is, in the state of FIG. 3A, the N poles are formed on the magnetic pole teeth U and X of the armature, the S poles are formed on the magnetic pole teeth V and Y, and the S pole and the magnetic poles are formed on the magnetic pole teeth U1 and X1. When energization is performed so that the N poles are simultaneously formed in the teeth V1 and Y1, the rotors 2A and 2B are rotationally driven in opposite directions as indicated by arrows.

  Similarly, in FIG. 3B, the magnetic pole teeth V and Y have S poles, the magnetic pole teeth W and Z have N poles, the magnetic pole teeth V1 and Y1 have N poles, and the magnetic pole teeth W1 and Z1 have S poles. As shown in FIG. 3C, the pole teeth X and U have S poles, the pole teeth W and Z have N poles, and the pole teeth X1 and U1 have N poles and poles. When energization is performed so that the south poles are simultaneously formed in the teeth W1 and Z1, the rotors 2A and 2B are rotationally driven in opposite directions indicated by arrows by a continuous rotational force.

  Magnetic fields generated by the permanent magnets 2a and 2b of the rotors 2A and 2B are configured such that a magnetic path is formed between the rotors 2A and 2B by an armature and closed. Therefore, the pair of rotors 2A and 2B have a magnetic coupling action at different magnetic pole surfaces, and always rotate in opposite directions in synchronization with each other.

  FIG. 4 is a time chart of the energization pattern to the coil during the operation shown in FIG. 3, and shows the energization pattern of the direct current supplied to each coil 4a of the magnetic pole teeth U to Z and each coil 4b of the magnetic pole teeth U1 to Z1. FIG. In each of the magnetic pole teeth U to Z and the magnetic pole teeth U1 to Z1, a space moving magnetic field (rotating magnetic field) is generated so as to be magnetized as shown in FIGS. 3 (a), 3 (b), and 3 (c). As described above, the rotor 2A and the rotor 2B rotate in synchronization with each other in opposite directions. The energization circuit for energizing the direct current of the pattern shown in FIG. 4 can be constituted by an existing electric element such as a semiconductor element, although not shown.

  FIG. 5 is a circuit diagram showing a state of energization of the coil during the operation shown in FIG. 5 (a) shows the energization state of the coil during the operation of FIG. 3 (a), FIG. 5 (b) shows the energization state of the coil during the operation of FIG. 3 (b), and FIG. The energization state of the coil at the time of operation | movement of FIG.3 (c) is shown.

In the embodiment shown in FIGS. 1 to 5 described above, a pair of rotors 2A and 2B to which permanent magnets 2a and 2b are attached are arranged in parallel, and a plurality of armatures 3a are arranged on the entire outer periphery of each rotor. _{1 to} 3a ₆ , 3b _{1 to} 3b ₆ are arranged, and the permanent magnets 2a and 2b form a plurality of pairs of different magnetic poles so that magnetic coupling can be performed between the rotors 2A and 2B via an armature. Synchronous reversal is enabled by the coupling action, and each bearing has an equal load balanced in the radial direction without applying an excessive eccentric load. And a long-life motor can be provided.

Further, according to the present embodiment, when the permanent magnets 2a and 2b are magnetically coupled between the adjacent rotors 2A and 2B, magnetic coupling can be performed between a plurality of pairs of different magnetic poles, so that the magnetic coupling area is large. In addition, since the air gap length can be made uniform, a large synchronizing force without pulsation can be obtained.
Furthermore, according to the present embodiment, when the pair of rotors 2A and 2B is driven, the armatures at symmetrical positions are energized so that they have different magnetic poles. Therefore, in addition to the magnetic coupling effect during non-energization, The magnetic coupling effect can be further enhanced.

  In the present embodiment, the multi-axis motor 24 is configured to synchronously invert the first rotating shaft 11 and the second rotating shaft 12 at the same speed. However, the multi-axis motor 24 includes the first rotating shaft 11 and the second rotating shaft 11. It is also possible to configure the rotating shaft 12 to be synchronously reversed at different speeds. Specifically, the number of magnetic poles of the permanent magnets of the rotors 2A and 2B may be varied, and the rotors 2A and 2B may be synchronously reversed at a rotation speed ratio corresponding to the ratio of the number of magnetic poles.

  FIG. 6 is a cross-sectional view showing another embodiment of the multistage centrifugal pump device of the present invention. As shown in FIG. 6, the first casing 18 and the second casing 19 are in contact with each other. The discharge side of the first casing 18 and the suction side of the second casing 19 are connected by a communication channel 22. Other configurations are the same as those of the embodiment shown in FIG.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

1 motor frame 2A, 2B rotor _{3a 1 ~3a 6, 3b 1 ~3b} 6 armature 4a, 4b coil 11 first rotation shaft 12 second rotation shaft 15 first centrifugal impeller 16 and the second centrifugal impeller 18 first casing 19 Second casing 22 Communication channel 24 Multi-axis motor 31 First mechanical seal (first shaft seal device)
32 Second mechanical seal (second shaft seal device)

Claims (4)

A first rotating shaft and a second rotating shaft arranged in parallel;
At least one first centrifugal impeller fixed to the first rotating shaft;
At least one second centrifugal impeller fixed to the second rotating shaft;
A first casing that houses the first centrifugal impeller;
A second casing for accommodating the second centrifugal impeller;
A communication channel connecting the first casing and the second casing;
A single multi-axis motor that rotates the first rotating shaft and the second rotating shaft in synchronization in opposite directions;
The multi-stage centrifugal pump device according to claim 1, wherein the first centrifugal impeller faces the multi-shaft electric motor, and the second centrifugal impeller faces the opposite direction to the first centrifugal impeller. A first shaft seal device disposed between the first centrifugal impeller and the multi-axis motor;
2. The multistage centrifugal pump device according to claim 1, further comprising a second shaft seal device disposed between the second centrifugal impeller and the multi-shaft electric motor.   The multistage centrifugal pump device according to claim 2, wherein the first shaft seal device and the second shaft seal device have the same configuration and the same size. The multi-axis motor is
A plurality of rotors connected to the first rotating shaft and the second rotating shaft and having permanent magnets attached thereto;
A plurality of armatures arranged on the outer periphery of each rotor;
The plurality of armatures include a magnetic pole tooth and a coil attached to the magnetic pole tooth, and the permanent magnet provided on the adjacent rotor can be reversed by magnetic coupling between the permanent magnets via the armature. In this way, when driving the adjacent rotors with a plurality of pairs of different magnetic poles, energization is performed so that the armatures at symmetrical positions become different magnetic poles, and magnetism is generated between the different magnetic poles of the armatures at the symmetrical positions. The multistage centrifugal pump device according to any one of claims 1 to 3, wherein the multistage centrifugal pump device is configured to be coupled.

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