JP2003184777A - Multistage motor pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-stage motor pump capable of minimizing the outside diameter of the pump as much as possible without making a passage structure complicated. <P>SOLUTION: In this multistage motor pump which introduces treated fluid discharged from an impeller 14 on a first stage and flowing to one side in an axial direction into an impeller 15 on a second stage as a flow in the other direction, a discharge side pump casing 3 in which the impeller 15 on the second stage is accommodated inside is provided. The discharge side pump casing 3 has first opening parts 51 to 54 which make the treated fluid flow to one side in the axial direction, a second opening part 57 which introduces the flow in the other direction into the impeller 15 on the second stage, and passage walls 60 to 63 for forming a plurality of volute passages 55, 56 which introduce the treated fluid discharged from the impeller 15 on the second stage to the outside in the radius direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage motor pump, and more particularly to a multistage motor pump having impellers arranged at both ends of a main shaft.

[0002]

2. Description of the Related Art Conventionally, there has been known an all-circumferential-type multistage pump in which an annular space through which a liquid to be handled flows is formed on the outer periphery of a motor frame. Such a full-circulation multi-stage pump is a kind of canned motor pump, and the rotor of the canned motor is rotatably supported by bearings. The liquid to be handled is guided from the suction port to the first-stage impeller to be boosted in pressure, further pressurized by the next-stage impeller, and finally discharged from the discharge port.

[0003]

In such an all-circumferential type multi-stage pump, impellers having opposite suction directions are arranged at both shaft ends to form a first pump section and a second pump. However, the axial thrust is balanced. Therefore, the first
It is necessary to provide a structure for introducing the axial flow discharged from the second pump part into the second pump part as a flow in the opposite direction and a structure for guiding the handling liquid pressurized in the second pump part to the discharge port. is there. Therefore, in the conventional multi-stage pump, measures such as forming a bypass flow passage by a connecting pipe are taken, but in the conventional multi-stage pump, the flow passage configuration is complicated and the outer diameter of the pump is increased. There is a problem that it ends up.

The present invention has been made in view of the above problems of the prior art, and provides a multi-stage motor pump capable of minimizing the outer diameter of the pump without complicating the flow passage structure. With the goal.

[0005]

In order to solve the problems in the prior art, one aspect of the present invention is the first aspect.
In a multi-stage motor pump in which the handling liquid discharged from one pump part flowing in one axial direction is introduced into the second pump part as a flow in the other direction, a pump casing containing the impeller of the second pump part inside. And a second opening for introducing a flow in the other direction into the impeller of the second pump section. And a flow passage wall that forms a plurality of volute flow passages that guide the handled liquid discharged from the impeller of the second pump unit to the outside in the radial direction.

As described above, in the above-mentioned pump casing, the handling liquid discharged from the first pump portion and flowing in one axial direction is introduced into the second pump portion as a flow in the other direction, and the second pump portion is introduced. Since the discharged handling liquid is guided to the outer side in the radial direction by the plurality of volute channels, the outer diameter of the pump can be minimized without complicating the channel configuration.

[0007] A preferred aspect of the present invention is characterized in that the plurality of volute flow paths are formed so as to join radially outwardly toward the discharge port.

In a preferred aspect of the present invention, the first opening is arranged between adjacent volute channels.

In a preferred aspect of the present invention, the pump casing includes an outer casing having a discharge port on an outer peripheral portion,
And an inner casing inserted into the outer casing.

A preferred aspect of the present invention is characterized in that a part of the volute flow passage is formed by an inner peripheral surface of the outer casing and a flow passage wall provided in the inner casing. By doing so, the flow path configuration can be further simplified.

The inner casing and the outer casing may be fixed to each other by welding. By fixing the casing and the inner casing by welding in this way, it is possible to secure rigidity and coaxiality of the mounting surface with other members.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a multi-stage motor pump according to the present invention will be described in detail below with reference to FIGS. FIG. 1 is a vertical sectional view showing a multistage motor pump according to an embodiment of the present invention. As shown in FIG. 1, the multi-stage motor pump according to the present embodiment has a suction side pump casing 1, a motor frame 2, a discharge side pump casing 3, a casing cover 4, and a canned motor 5.
Basically consists of

The motor frame 2 is formed of stainless cast steel so as to be integrated with an outer cylinder 6 and a rib 7 provided on the outer side thereof. Furthermore, on the outer peripheral portion of the outer cylinder 6,
A plane seat 8 for mounting the frequency converter is integrally provided. An annular space S1 through which the handled liquid flows is formed between the motor frame 2 and the outer cylinder 6.

The stator 9 of the canned motor 5 is housed in the motor frame 2 by shrink fitting or press fitting. Inside the stator 9, a rotor 11, which is shrink-fitted and fixed to the main shaft 10, is rotatably accommodated.
A motor frame side plate 12 formed of stainless cast steel is hermetically welded to the axially upper end of the motor frame 2. The flat seat 8 has a flat surface, and a case 13 for accommodating a frequency converter (not shown) is attached to the flat seat.

At both ends of the main shaft 10 of the canned motor 5,
One impeller 14 and 15 are fixed,
The impellers 14 and 15 are formed with suction portions 14a and 15a that are open outward in the axial direction. These impellers 14 and 15 are housed inside the suction side pump casing 1 and the discharge side pump casing 3, respectively. The impellers 14 and 15 are appropriately selected from cast products made of stainless cast steel and generate a high lift (pressure) of 100 m per stage.

The main shaft 10 is supported at its both ends by bearings provided on the motor frame 2. In the bearing portion below the main shaft 10 (first stage), the bearing bracket 20 is provided with a radial bearing 21, and the sleeve 23 that abuts the washer 22 forms a sliding portion with the radial bearing 21. The bearing bracket 20 is in contact with the end of the motor frame 2.

In the bearing portion above the main shaft 10 (second stage), a bearing bracket 30 is provided with a radial bearing 31 and a fixed thrust bearing 32. The end surface of the radial bearing 31 also has a function as a fixed-side thrust sliding member, and the rotation-side thrust bearing 34 held by the thrust disk 33 is in sliding contact with the end surface of the radial bearing 31. A rotary thrust bearing 35 is provided so as to face the fixed thrust bearing 32. The rotary thrust bearing 35 is held by a thrust disk 36.
The sleeve 37 forms a sliding portion with the radial bearing 31.

The above-mentioned radial bearings 21, 31,
Thrust bearings 32, 34, 35 and sleeves 23, 3
The material of No. 7 is silicon carbide which is a kind of ceramic material, and the materials of the bearing brackets 20, 30 and the thrust disks 33, 36 are stainless steel. In addition, the thrust bearing 3 that supports the axial thrust load
Reference numerals 2, 34, and 35 are plain bearings.

The canned motor 5 is a two-pole three-phase induction motor, and is operated at a high speed of about 7,500 revolutions per minute by electric power (for example, 125 Hz, 200 V) supplied from the frequency converter. As a result, the impellers 14, 1
A miniaturization of the pump including 5 has been achieved. At this time,
The handling liquid flowing in the flow path S1 between the motor frame 2 and the outer cylinder 6 shields noise having a relatively high frequency generated as the speed increases, and also effectively causes the canned motor 5 and the frequency converter that generate heat. Cooling.

A suction side pump casing 1 and a discharge side pump casing 3 are fixed to both axial sides of an outer cylinder 6 provided outside the motor frame 2. A casing cover 4 is attached to the upper portion of the discharge side pump casing 3. Suction side pump casing 1
Is provided with a suction port 1a, and a flow path S2 is formed from the suction port 1a to the suction portion 14a of the first-stage impeller 14. Further, the wall forming the flow path S2 forms a flow path S3 that connects the suction portion 14a of the impeller 14 and the above-described flow path S1. Thereby, the fluid sucked into the flow path S2 from the suction port 1a of the suction side pump casing 1 passes through the suction portion 14a of the first-stage impeller (first pump portion) 14 and is pressurized by the impeller 14. It Then, the pressurized fluid flows into the flow path S1 through the flow path S3.

FIG. 2 is an enlarged sectional view showing the discharge side pump casing 3 shown in FIG. 1, and FIG. 3 is a plan view of FIG. Figure 2
As shown in FIG. 3, the discharge side pump casing 3 includes an outer casing 40 having a discharge port 40 a on the outer peripheral portion and an inner casing 50 inserted into the outer casing 40. A second-stage impeller (second pump unit) 15 is housed inside the inner casing 50. The outer casing 40 and the inner casing 50 are formed of a cast stainless steel material, and the outer casing 40 and the inner casing 50 are fixed to each other by welding. Outer casing 40
By fixing the inner casing 50 and the inner casing 50 by welding, rigidity and coaxiality of the mounting surface A with the outer cylinder 6, the insertion surface B of the main shaft 10, and the insertion surface C of the liner portion of the impeller 15 are secured.

As shown in FIG. 3, a plurality of first openings 51 to 5 are formed on the upper surface 50a (see FIG. 2) of the inner casing 50.
4 are formed, and the first openings 51 to 54 communicate with the flow path S1. In the casing cover 4,
First openings 51 to 54 formed in the inner casing 50
A space S4 that communicates with the fluid is formed, and the fluid that has been pressurized by the first-stage impeller 14 and has flowed into the flow path S1 is
The space S4 of the casing cover 4 is reached through the first openings 51 to 54 of the inner casing 50.

Further, in the inner casing 50, two volute flow paths 5 extending from the discharge portion of the second-stage impeller 15 toward the outer side in the radial direction to the discharge port 40a of the outer casing 40.
Flow path walls 60 to 63 forming 5, 56 are provided. The volute channels 55 and 56 are shown by hatching in FIG. This volute channel 55, 5
6 are formed so as to merge on the outer side in the radial direction toward the discharge port 40a of the outer casing 40.

The central portion of the inner casing 50, that is,
At the portion where the suction portion 15a of the second-stage impeller 15 is located, the suction portion 15 of the impeller 15 is set so that the flow of the space S4 of the casing cover 4 is in the direction opposite to the flow of the flow path S1.
The 2nd opening part 57 which leads to a is formed. Therefore,
The handling liquid that has reached the space S4 of the casing cover 4 through the first openings 51 to 54 of the inner casing 50 is pressurized by the impeller 15 through the second opening 57 of the inner casing 50. The fluid pressurized by the impeller 15 is
It passes through the volute flow paths 55 and 56 described above, merges in the radial outside, and is discharged from the discharge port 40a of the outer casing 40.

Here, of the first openings 51 to 54 of the inner casing 50, the openings 53 and 54 are arranged between the adjacent volute passages 55 and 56. Further, a part 55 a of the volute flow channel 55 is formed by the inner peripheral surface of the outer casing and a flow channel wall 61 provided on the inner casing 50, and a part 55 b of the volute flow channel 55.
Is formed by the inner peripheral surface of the outer casing and the flow channel wall 62 provided in the inner casing 50. By doing so, the flow path configuration can be further simplified.

In this embodiment, the impellers 14 and 15 arranged at both shaft ends of the main shaft 10 have suction directions opposite to each other, so that the axial thrust can be balanced. Further, in the discharge side pump casing 3, the handling liquid discharged from the first pump unit 14 and flowing in one of the axial directions is introduced into the second pump unit 15 as a flow in the other direction, and the second pump unit 15 Since the discharged handling liquid is guided to the outside in the radial direction by the plurality of volute channels 55, 56, the outer diameter of the pump can be minimized without complicating the channel configuration. In the present embodiment, the two-stage motor pump is described as an example, but the present invention is not limited to this, and the present invention can be applied to a three-stage or more motor pump.

Although one embodiment of the present invention has been described so far, it goes without saying that the present invention is not limited to the above-described embodiment and may be implemented in various different forms within the scope of the technical idea thereof.

[0028]

As described above, according to the present invention, in the pump casing, the handling liquid discharged from the first pump portion and flowing in one of the axial directions is changed to the second direction to be the second direction.
Since the handling liquid discharged from the second pump part is introduced to the outside in the radial direction by a plurality of volute flow paths, the outer diameter of the pump is minimized without complicating the flow path structure. can do.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a multi-stage motor pump according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a discharge side pump casing shown in FIG.

FIG. 3 is a plan view of FIG.

[Explanation of symbols]

1 Suction side pump casing 1a Suction port 2 motor frame 3 Discharge side pump casing 4 casing cover 5 canned motor 6 outer cylinder 7 ribs 8 plane 9 stator 10 spindles 11 rotor 12 Motor frame side plate 13 cases 14,15 Impeller 20,30 Bearing bracket 21,31 radial bearing 22 washer 23,37 Sleeve 32 Fixed thrust bearing 33,36 thrust disk 34,35 Rotation side thrust bearing 40 Outer casing 40a discharge port 50 Inner casing 51-54 1st opening 55,56 volute flow path 57 Second opening 60-63 Channel wall

Continued front page    (72) Inventor Riki Makino             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION (72) Inventor Keita Uei             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION F term (reference) 3H034 AA01 BB01 BB06 BB17 CC03                       DD10 DD12 DD17 EE12

Claims (5)

[Claims] 1. A multi-stage motor pump in which a handling liquid discharged from a first pump portion and flowing in one axial direction is introduced into a second pump portion as a flow in the other direction, wherein an impeller of the second pump portion is provided. And a pump casing that accommodates therein, wherein the pump casing has a first opening through which the handling liquid flowing in the one axial direction flows, and a flow in the other direction to an impeller of the second pump unit. A second opening portion to be introduced; and a flow passage wall forming a plurality of volute flow passages for guiding the handling liquid discharged from the impeller of the second pump portion to the outside in the radial direction. Multi-stage motor pump. 2. The multi-stage motor pump according to claim 1, wherein the plurality of volute flow passages are formed so as to join together on the outer side in the radial direction toward the discharge port. 3. The first opening is arranged between adjacent volute channels.
The multi-stage motor pump described in. 4. The pump casing includes an outer casing having a discharge port on an outer peripheral portion thereof, and an inner casing inserted into the outer casing. A multi-stage motor pump according to item. 5. The multi-stage motor according to claim 4, wherein a part of the volute flow passage is formed by an inner peripheral surface of the outer casing and a flow passage wall provided on the inner casing. pump.