JP3176494B2 - Multi-stage centrifugal pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage centrifugal pump, and more particularly to a multi-stage centrifugal pump provided with a thrust bearing having a groove for generating dynamic pressure at an impeller suction port.

[0002]

2. Description of the Related Art In a conventional multistage centrifugal pump, all impellers are fixed to a main shaft, and a thrust load applied to the main shaft is supported by a thrust bearing. FIG. 4 is a cross-sectional view of a conventional multi-stage centrifugal pump. In FIG. 4, reference numeral 20 denotes a casing formed of a three-piece body, and the casing 20 has a suction port 21 and a discharge port 22. The impeller 2 is provided in the casing 20.
3, 24 are provided in multiple stages. These impellers 2
3 and 24 are all fixed to the main shaft 26.
6 is supported by the radial bearings 27 and 28, and the load in the thrust direction is supported by the thrust bearings 29 and 30 including the end faces 27a and 28a of the radial bearings 27 and 28 and the thrust disks 29a and 30a. I have.

[0003]

In a conventional multi-stage centrifugal pump as shown in FIG. 4, all the impellers are fixed to the main shaft, and the suction ports of all the impellers are in the same direction. In operation, all the thrust load is applied to the thrust bearing 29. At this time, the load supported by the thrust bearing was the sum of the loads acting on the respective impellers, and was a large load. Therefore, since it is necessary to receive this large thrust load with one thrust bearing,
There is also a problem that a large thrust bearing corresponding to the load is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and disperses a load applied to a thrust bearing by installing at least one or more impellers movably on a pump main shaft, thereby reducing the size of the thrust bearing. It is an object of the present invention to provide a multi-stage centrifugal pump capable of reducing the pressure.

[0005]

In order to achieve the above-mentioned object, a multi-stage centrifugal pump according to the present invention is a multi-stage centrifugal pump provided with two or more impellers, wherein at least one or more impellers are mounted on a main shaft. Fixed, and at least one or more impellers are installed so as to be movable on the pump main shaft in a direction parallel to the pump shaft center, and a thrust bearing having a groove for generating dynamic pressure is provided at an impeller suction port ; Thrust bearing houses impeller
A fixed bearing fixed to the casing side and the fixed bearing
And a rotary bearing fixed to the impeller .

[0006]

According to the present invention having the above-described structure, at least one or more impellers can be moved on the pump main shaft in a direction parallel to the pump shaft center, and a dynamic pressure generating groove is formed in the impeller suction port. By providing the thrust bearings provided, the thrust load applied to each impeller can be received by the thrust bearing provided at each impeller suction port, the thrust load can be dispersed, and the size of the thrust bearing can be reduced. be able to. In addition, the thrust bearing provided at each impeller suction port constitutes a liner part, and the gap of this liner part becomes small, so that leakage of the handling liquid from the liner part can be made small,
This has the effect of increasing pump efficiency.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the multistage centrifugal pump according to the present invention will be described below with reference to FIGS. FIG. 1 is a cross-sectional view showing the entire configuration of a multi-stage centrifugal pump according to the present invention. In FIG. 1, reference numeral 1 denotes a casing, and the casing 1 integrally includes a suction port 2 and a discharge port 3. In the casing 1, the inner casing 8 is connected in a multi-stage (three-stage in the embodiment), and the first-stage impeller 4, the second-stage impeller 5, and the third-stage 6 are accommodated respectively.

The first stage impeller 4 is integrally fixed to the main shaft 7, and the second stage impeller 5 and the third stage impeller 6 are fixed to the main shaft 7 by a key or the like. Is rotated integrally with the main shaft 7 by receiving the rotational force from the main shaft 7,
The main shaft 7 is configured to be movable in the horizontal direction (axial direction).

Further, a thrust bearing 9 having a groove for generating dynamic pressure is provided at a suction port of each of the impellers 4, 5, and 6. The thrust bearing 9 is composed of a fixed bearing 10 made of ceramic fixed to the inner casing 8 accommodating the impeller of each stage, and a ceramic installed opposite to the fixed bearing 10 and fixed integrally to each impeller. Rotary bearing 13
And

FIG. 2 shows the structure of a fixed bearing or a rotary bearing. FIG. 2 (a) is a longitudinal sectional view, and FIG. 2 (b) is a side view. As shown in FIG. 2, the fixed bearing 10 is provided with a cushioning material 11 made of an elastic material so as to cover a surface excluding a sliding surface, and a case 12 is provided outside the cushioning material 11. Similarly, the rotating bearing 13 is provided with a cushioning material 14 made of an elastic material so as to cover the surface excluding the sliding surface, and a case 15 is provided outside the cushioning material 14.

As shown in FIG. 2, a spiral groove 17 for generating dynamic pressure is formed on the sliding contact surface on either the fixed bearing 10 or the rotary bearing 13. The fixed bearing 10 or the rotary bearing 13 has a detent 18 for rotation prevention.
Is formed, and the case 12 (or 1
5) The projection 19 extending more in the radial direction is engaged, and the fixed bearing 10 or the rotating bearing 13 is prevented from rotating with respect to the case 12 (or 15). In the embodiment shown in FIG. 2, a projection is provided on the case 12 (or 15) to prevent the fixed bearing 10 or the rotating bearing 13 from rotating. A projection may be provided.

FIG. 3 shows another embodiment of the thrust bearing of the present invention, and FIG. 3 shows a bearing having no spiral groove. That is, the fixed bearing 10 or the rotary bearing 13 of the present embodiment is provided with the cushioning material 11 (or 14) made of an elastic material so as to cover the surface excluding the sliding surface, and further the outside of the cushioning material 11 (or 14). Is provided with a case 12 (or 15). It should be noted that no projection or depression is provided for the rotation of the fixed bearing 10 or the rotary bearing 13.

According to the multi-stage centrifugal pump constructed as described above, the second-stage impeller 5 and the third-stage impeller 6 can be moved in the horizontal direction (axial direction) with respect to the main shaft 7. A thrust load on the main shaft 7 applied to the impellers 5 and 6 in the horizontal direction can be received by the thrust bearings 9 provided at the respective impeller suction ports, and the thrust load can be dispersed. . In addition, the rotary bearing 13 provided on each impeller constitutes a liner portion, and the gap of the liner portion becomes delicate, so that leakage of the handling liquid from the liner portion can be reduced.

[0014]

As described above, according to the present invention, at least one or more impellers can be moved on the main shaft in the horizontal direction, and the thrust bearing has a groove for generating dynamic pressure at the impeller suction port. Is provided, the thrust load applied to each impeller can be received by the thrust bearing provided at each impeller suction port, and the size of the thrust bearing can be reduced.

Further, the thrust bearing provided at each impeller suction port constitutes a liner, and the gap between the liners is small, so that the leakage of the handling liquid from the liner can be reduced, and the pump efficiency increases. This has the effect.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a multi-stage centrifugal pump according to the present invention.

FIG. 2 is a view showing a structure of a thrust bearing in the multi-stage centrifugal pump according to the present invention. FIG. 2 (a) is a longitudinal sectional view of the thrust bearing, and FIG. 2 (b) is a side view of the thrust bearing.

FIG. 3 is a view showing a structure of a thrust bearing in the multi-stage centrifugal pump according to the present invention. FIG. 3 (a) is a longitudinal sectional view of the thrust bearing, and FIG. 3 (b) is a side view of the thrust bearing.

FIG. 4 is a longitudinal sectional view showing an example of a conventional multi-stage centrifugal pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Suction port 3 Discharge port 4,5,6 Impeller 7 Main shaft 8 Inner casing 9 Thrust bearing 10 Fixed bearing 11 Buffer material 12 Case 13 Rotating bearing 14 Buffer material 15 Case 17 Spiral groove 18 Depression

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-229990 (JP, A) JP-A-51-83201 (JP, A) Fully open 1981-161195 (JP, U) Really open 1984 90094 (JP, U) Japanese Utility Model Application No. Sho 61-105793 (JP, U) Japanese Patent Application No. 63-109570 (Japanese Utility Model Application No. 2-31398) JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 1/08 F04D 29/04

Claims (4)

(57) [Claims] 1. A multi-stage centrifugal pump provided with two or more impellers, wherein at least one or more impellers are fixed to a main shaft, and at least one or more impellers are pumped in a direction parallel to a pump shaft center. placed on the spindle movably provided a thrust bearing having a dynamic pressure generating grooves in the impeller inlet part, the
The thrust bearing is fixed to the casing that houses the impeller.
Fixed bearing and an impeller installed opposite to the fixed bearing.
And a rotary bearing fixed to the shaft . 2. A cushioning material is provided on at least one of a fixed bearing and a rotating bearing of the thrust bearing, or at least one other surface except a sliding surface of both bearings.
The described multi-stage centrifugal pump. 3. A cushioning material is provided on at least one of the fixed bearing and the rotating bearing of the thrust bearing, or at least one other surface except the sliding surface of both bearings, and a case is provided outside the cushioning material. The multi-stage centrifugal pump according to claim 1, wherein: 4. A cushioning material is provided on at least one of the fixed bearing and the rotating bearing of the thrust bearing, or at least one other surface except a sliding surface of both bearings, and the bearing is provided outside the cushioning material. 2. The multi-stage centrifugal pump according to claim 1, further comprising a case having a protrusion or a depression for preventing rotation.