JP3985860B2 - Multistage motor pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multistage motor pump, and more particularly to a multistage motor pump in which impellers are arranged at both ends of a main shaft.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an all-around flow type multi-stage pump in which an annular space through which a liquid to be handled flows on the outer periphery of a motor frame is known. Such an all-around multistage pump is a kind of canned motor pump, and the rotor of the canned motor is rotatably supported by a bearing. The handling liquid is introduced from the suction portion to the first stage impeller, and the pressure is increased. Further, the pressure is increased by the next stage impeller, and finally discharged from the discharge port.
[0003]
[Problems to be solved by the invention]
However, in the conventional all-around multistage pump, if the handling liquid contains small bubbles or dissolved gas, the air may stay around the rotor due to the centrifugal separation action as the continuous operation time of the pump elapses. is there. If air stays around the rotor, it may cause poor lubrication of the sliding surface of the bearing, which may cause damage to the bearing. In particular, when the above-described multi-stage pump is configured as a vertical pump, the presence of the pump portion disposed at the upper portion makes it easier for air to stay.
[0004]
The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide a multistage motor pump capable of improving the lubrication of the sliding surface of the bearing and preventing the bearing from being damaged. To do.
[0005]
[Means for Solving the Problems]
In order to solve such problems in the prior art, one aspect of the present invention is the above-described multistage motor pump including a bearing portion having a fixed side sliding bearing and a rotating side sliding bearing lubricated by a handling liquid. An introduction flow path for guiding a part of the handling liquid whose pressure is higher than the pressure of the bearing section to the bearing section, and handling liquid introduced through the introduction flow path between the fixed side sliding bearing and the rotation side sliding bearing. The introduction passage is formed in a thrust disk that holds the distance piece disposed between the impeller and the bearing and the rotating side sliding bearing. The multistage motor pump is characterized in that the injection flow path is formed in the thrust disk .
[0006]
Thus, according to the present invention, the introduction flow path for guiding a part of the handling liquid having a pressure higher than the pressure of the bearing section to the bearing section, and the handling liquid between the fixed side sliding bearing and the rotating side sliding bearing. Since the injection flow path for injecting toward the sliding surface is formed and self-water injection is performed, air stays around the rotor of the motor is prevented by the injection of the handling liquid, and the sliding surface of the bearing It is possible to improve the lubrication of the bearing and prevent the bearing from being damaged.
[0008]
According to a preferred aspect of the present invention, a first pump part that boosts the handling liquid guided from the suction part by at least one impeller, and the handling liquid discharged from the first pump part is at least one impeller. And a second pump part that boosts the pressure of the impeller of the first pump part and the impeller of the second pump part are opposite to each other. Thus, if the suction directions of the impeller of the first pump unit and the impeller of the second pump unit are opposite to each other, the axial thrust can be balanced.
[0009]
In this case, an outer cylinder is provided outside the motor frame to form an annular space through which the liquid to be handled flows, the first pump part is disposed on one shaft end side, and the second pump end is disposed on the other shaft end side. It is preferable to arrange a pump part.
[0010]
Another preferred embodiment of the present invention is characterized in that the sliding surface between the bearings is a sliding surface of a thrust bearing that supports an axial thrust load.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a multistage motor pump according to the present invention will be described in detail with reference to FIGS. 1 to 3. FIG. 1 is a longitudinal sectional view showing a multistage motor pump according to an embodiment of the present invention. As shown in FIG. 1, the multistage motor pump in the present embodiment basically includes 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.
[0012]
The motor frame 2 is formed of a cast stainless steel material so as to be integrated with an outer cylinder 6 and a rib 7 provided on the outside thereof. Further, a flat seat 8 for attaching the frequency converter is integrally provided on the outer peripheral portion of the outer cylinder 6. Between the motor frame 2 and the outer cylinder 6, an annular space S <b> 1 in which the handling liquid flows is formed.
[0013]
A stator 9 of the canned motor 5 is housed in the motor frame 2 by shrink fitting or press fitting, and a rotor 11 fastened by shrink fitting on the main shaft 10 is housed rotatably inside the stator 9. Is done. A motor frame side plate 12 formed of stainless cast steel is hermetically welded to the upper end of the motor frame 2 in the axial direction. The plane seat 8 has a flat surface, and a case 13 for receiving a frequency converter (not shown) is attached to the plane seat.
[0014]
One impeller 14 and 15 is fixed to each end of the main shaft 10 of the canned motor 5, and suction portions 14 a and 15 a that open outward in the axial direction are formed on the impellers 14 and 15. Has been. These impellers 14 and 15 are accommodated in the suction side pump casing 1 and the discharge side pump casing 3, respectively. The impellers 14 and 15 are appropriately selected from cast castings made of stainless steel, and generate a high head (pressure) as high as 100 m per stage.
[0015]
The main shaft 10 is supported at both ends by bearing portions provided on the motor frame 2. In the bearing portion below the main shaft 10 (first stage), a radial bearing 21 is provided on the bearing bracket 20, and a sleeve 23 that contacts 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.
[0016]
Further, a radial bearing 31 and a fixed-side thrust bearing 32 are provided in the bearing bracket 30 in the bearing portion above the main shaft 10 (second stage). The end surface of the radial bearing 31 is also provided with a function as a fixed-side thrust sliding member, and the rotating-side thrust bearing 34 held by the thrust disk 33 is in sliding contact with the end surface of the radial bearing 31. A rotation-side thrust bearing 35 is provided facing the fixed-side thrust bearing 32. The rotation side thrust bearing 35 is held by a thrust disk 36. The sleeve 37 forms a sliding portion with the radial bearing 31.
[0017]
The radial bearings 21 and 31, the thrust bearings 32, 34, and 35 and the sleeves 23 and 37 are made of silicon carbide, which is a kind of ceramic material. The bearing brackets 20 and 30 and the thrust disks 33 and 36 are made of the same material. The material is stainless steel. The thrust bearings 32, 34, and 35 that support the axial thrust load are constituted by sliding bearings.
[0018]
The canned motor 5 is a two-pole three-phase induction motor, and is operated at a high speed of about 7500 revolutions per minute by electric power (for example, 125 Hz, 200 V) supplied from the frequency converter. As a result, downsizing of the pump including the impellers 14 and 15 is achieved. At this time, the handling liquid flowing in the flow path S1 between the motor frame 2 and the outer cylinder 6 blocks the relatively high-frequency noise generated with the increase in speed, and generates the generated canned motor 5 and frequency converter. Cool effectively.
[0019]
Here, the suction side pump casing 1 and the discharge side pump casing 3 are respectively fixed to both sides in the axial direction of the outer cylinder 6 provided outside the motor frame 2. A casing cover 4 is attached to the upper part of the discharge side pump casing 3. The suction-side pump casing 1 includes a suction nozzle 1a, and a flow path S2 is formed from the suction nozzle 1a to the suction portion 14a of the first stage impeller 14. Further, a flow path S3 that connects the suction portion 14a of the impeller 14 and the above-described flow path S1 is formed by the wall that forms the flow path S2. Thereby, the fluid sucked into the flow path S2 from the suction nozzle 1a of the suction side pump casing 1 is boosted by the impeller 14 through the suction portion 14a of the first stage impeller (first pump portion) 14. The Then, the pressurized fluid flows into the flow path S1 through the flow path S3.
[0020]
The discharge-side pump casing 3 is formed with a flow path S4 communicating with the flow path S1 and a flow path S5 from the discharge portion of the second stage impeller 15 to the discharge nozzle 3a. The casing cover 4 is provided with a space S6 communicating with the flow path S4 formed in the discharge side pump casing 3, and the central portion of the discharge side pump casing 3, that is, the suction portion 15a of the second stage impeller 15. The part where is located is open.
[0021]
Therefore, the fluid pressurized by the first stage impeller 14 and flowing into the flow path S1 is introduced into the flow path S4 of the discharge-side pump casing 3 and reaches the space S6 of the casing cover 4. The fluid is pressurized from the space S6 of the casing cover 4 through the suction part 15a of the impeller 15 by the impeller (second pump part) 15 and passes through the flow path S5 to the discharge nozzle 3a of the discharge side pump casing 3. It is discharged from. As shown in FIG. 1, in this embodiment, since the suction directions of the impellers 14 and 15 arranged at both shaft ends of the main shaft 10 are opposite to each other, the axial thrust can be balanced.
[0022]
A distance piece 40 for securing a distance between the impeller 14 and the thrust disk 36 is disposed between the second stage impeller 14 and the thrust disk 36, and the distance piece 40 is arranged on the main shaft 10. Is inserted. 2A is a plan view of the distance piece 40, FIG. 2B is a sectional view, and FIG. 2C is a bottom view. As shown in FIGS. 2A to 2C, the distance piece 40 has a substantially cylindrical shape, and an introduction groove 41 is formed in the upper part of the distance piece 40. A communication groove 42 communicating with the introduction groove 41 and extending in the axial direction when formed on the main shaft 10 is formed on the inner peripheral surface of the distance piece 40. In the present embodiment, the four introduction grooves 41 and the communication grooves 42 are formed, but the present invention is not limited to this.
[0023]
3A is a plan view of the thrust disk 36, FIG. 3B is a cross-sectional view, FIG. 3C is a bottom view, and FIG. 4 is a partially enlarged view of a bearing portion of the multistage motor pump shown in FIG. . As shown in FIGS. 3A to 3C, a communication groove 51 that communicates with the communication groove 42 formed in the distance piece 40 is formed on the inner peripheral surface of the thrust disk 36. An injection port (injection flow path) 52 that communicates with the communication groove 51 and extends in the radial direction is formed below the thrust disk 36. In the present embodiment, the four communication grooves 42 and the injection ports 52 are formed, but the present invention is not limited to this.
[0024]
With such a configuration, a part of the handling liquid pressurized by the second stage impeller 15 flows into the communication groove 42 from the introduction groove 41 of the distance piece 40 as shown by an arrow in FIG. It flows into the communication groove 51 of the disk 36. The handling liquid that has flowed into the communication groove 51 of the thrust disk 36 is directed toward the sliding surface 53 (see FIG. 4) between the rotation-side thrust bearing 35 and the fixed-side thrust bearing 36 held by the thrust disk 36 from the injection port 52. Is injected.
[0025]
As described above, in the present embodiment, the introduction flow path (that is, the introduction groove 41 and the communication groove 52 of the distance piece 40, the thrust disk 36, and the thrust disk 36) introduces a part of the handling liquid having a pressure higher than the pressure of the bearing portion to the bearing portion. A communication groove 51) and an injection flow path (that is, an injection port 52 of the thrust disk 36) for injecting the handling liquid toward the sliding surface 53 between the rotation-side thrust bearing 35 and the fixed-side thrust bearing 36. Therefore, air is prevented from staying around the rotor 11 of the canned motor 5 due to the injection of the handling liquid, and the sliding surface 53 of the bearing can be well lubricated to prevent the bearing from being damaged. .
[0026]
In this embodiment, a two-stage motor pump has been described as an example. However, the present invention is not limited to this, and the present invention can also be applied to a three-stage or more motor pump. In this embodiment, an example in which the introduction flow path is formed in the distance piece 40 and the thrust disk 36 and the injection flow path is formed in the thrust disk 36 has been described. It is good also as forming in other members.
[0027]
Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.
[0028]
【The invention's effect】
As described above, according to the present invention, the introduction flow path for guiding a part of the handling liquid having a pressure higher than the pressure of the bearing section to the bearing section, and the handling liquid between the rotation side sliding bearing and the fixed side sliding bearing. A self-water injection is formed by forming an injection flow path that injects toward the sliding surface of the motor, preventing air from staying around the rotor of the motor due to the injection of the handling liquid, and sliding of the bearing The surface can be well lubricated to prevent damage to the bearing.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a multistage motor pump according to an embodiment of the present invention.
2A is a plan view showing a distance piece of the multistage motor pump shown in FIG. 1, FIG. 2B is a cross-sectional view, and FIG. 2C is a bottom view.
3A is a plan view of a thrust disk of the multistage motor pump shown in FIG. 1, FIG. 3B is a cross-sectional view, and FIG. 3C is a bottom view.
4 is a partially enlarged view of a bearing portion of the multistage motor pump shown in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Suction side pump casing 1a Suction nozzle 2 Motor frame 3 Discharge side pump casing 4 Casing cover 5 Canned motor 6 Outer cylinder 7 Rib 8 Plane seat 9 Stator 10 Spindle 11 Rotor 12 Motor frame side plate 13 Cases 14 and 15 Impellers 20 and 30 Bearing bracket 21, 31 Radial bearing 22 Washer 23, 37 Sleeve 32 Fixed thrust bearing 33, 36 Thrust disk 34, 35 Rotating thrust bearing 40 Distance piece 41 Introducing groove 42, 51 Contact groove 52 Injection port 53 Sliding surface

Claims (4)

In a multi-stage motor pump having a bearing portion having a fixed side sliding bearing and a rotating side sliding bearing lubricated by a handling liquid,
An introduction flow path for guiding a part of the handling liquid having a pressure higher than the pressure of the bearing portion to the bearing portion;
An injection flow path for injecting the handling liquid introduced through the introduction flow path toward the sliding surface between the fixed side sliding bearing and the rotation side sliding bearing ;
Forming the introduction flow path in the thrust disk holding the distance piece disposed between the impeller and the bearing and the rotation-side sliding bearing;
A multi-stage motor pump , wherein the injection flow path is formed in the thrust disk . A first pump part that boosts the handling liquid guided from the suction part by at least one impeller, and a second pump part that boosts the handling liquid discharged from the first pump part by at least one impeller. And
The multistage motor pump according to claim 1 , wherein the suction directions of the impeller of the first pump section and the impeller of the second pump section are opposite to each other. An outer cylinder is provided outside the motor frame to form an annular space through which the liquid to be handled flows.
The multistage motor pump according to claim 2 , wherein the first pump part is arranged on one shaft end side and the second pump part is arranged on the other shaft end side. The multistage motor pump according to any one of claims 1 to 3 , wherein the sliding surface between the bearings is a sliding surface of a thrust bearing that supports an axial thrust load.

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