JPS6339438Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a balanced multi-stage pump with an improved sliding part on the anti-suction side.

Balanced multistage pumps are widely used for fluid transportation of various types of drainage and slurry, and one example is one with a structure as shown in FIG. 1.

In FIG. 1, the fluid to be transported is sucked in by the first impeller 1 from the suction port,
It is pressurized by the second impeller 2 and the third impeller 3 and sent to the anti-suction side (one end side opposite to the suction port in the main axis direction). Next, it is further pressurized by the fourth impeller 4 and the fifth impeller 5 and is discharged from the discharge port 0. In this manner, in the balanced multi-stage pump, the force in the thrust direction applied to the main shaft 6 of the pump is balanced by changing the flow direction and pumping the fluid approximately in the middle of the pressurizing stage.

However, in the sliding part on the anti-suction side of such a balanced multi-stage pump, fluid pressurized to about 5 to 30 kg/ ^cm2 flows in the direction of arrow P, as shown in an enlarged view in Figure 2. A part of it passes through the inner end 81a of the stage piece 81, which forms part of the casing 7, from the main shaft 6, and collides with the rotating and sliding portion of the balance sleeve 91 and balance bush 101. . Therefore, if the fluid to be pumped is a slurry containing solid contaminants such as muddy water, particles of the contaminants collide with the exposed portion of the balance sleeve 91 on the fluid passage side, and also cause the balance sleeve 91 and the balance bush 101 and causes wear, shortening the life of the pump.

The balanced multi-stage pump of this invention has been proposed with the aim of eliminating the above-mentioned drawbacks, and is designed to cover the entire inner end surface of the balance sleeve in the axial direction of the non-suction side sliding part. In this way, one side is brought into contact with the other, and the annular balance collar is fixed by fitting the mounting hole into the main shaft.
It is characterized in that the balance collar covers the inner end surface of the balance bush in the axial direction.

This invention will be explained below based on three embodiments shown in FIGS. 3 to 5. These drawings in FIGS. 3 to 5 all show only the sliding portion on the anti-suction side of the balanced multistage pump. The one shown in Fig. 1, which is explained as an example of a conventional balanced multistage pump, is as follows.
Although it has five sets of impellers, this idea can also be used for those that increase or decrease the number of impellers depending on the type of fluid, required discharge pressure, etc., or those that increase the number of changes in flow direction. applicable.

3 to 5, 4 is an impeller attached to the main shaft 6, 7 is a casing, 8 is a stage piece forming a part of the casing, and 9 is the main shaft 6.
10 is a balance bush fixed to the casing 7.
Balance color 11, which is the main part of this idea,
It is formed into an annular plate made of a wear-resistant metal material, etc., and has a mounting hole 1 in its middle for fitting into the main shaft 6.
It has 1a. Balance color 1 in the illustrated example
1 is a distance sleeve 1 that penetrates the main shaft 6 through its mounting hole 11a and is located at the front and rear of the main shaft 6.
Although the balance collar 11 is attached to the main shaft 6 by being clamped between the balance collar 11 and the balance sleeve 9, any other fixing means may be used to attach the balance collar 11 to the main shaft 6.

In the above-described installed state, this balance collar 11 has one flat surface in close contact with the inner end surface of the balance sleeve 9 in the axial direction, and at the same time, the outer peripheral portion of the one surface is in close contact with the inner end surface of the balance bush 10 in the axial direction. It is made to face the inner end surface and cover the inner end surface. Therefore, in order to implement this invention with respect to the conventional example shown in FIG. . With such improvements, in the present invention, the stage piece 8 to the balance collar 11
This makes it possible to form a substantially smooth surface of the fluid passage 12 in the portion leading to the surface.

In addition, in the first embodiment shown in FIG. 3, the balance collar 11 is simply formed into an annular plate.
In the second embodiment shown in FIG. 4, the outer peripheral corner of the balance collar 11 on the fluid passage 12 side is cut off, and in the third embodiment shown in FIG. An example has been shown in which the stage piece 8 is formed in a stepped portion, and the opposing portion of the stage piece 8 is formed to correspond to the stepped portion, so that the gap between the two 11 and 8 is bent.

According to the balanced multi-stage pump of this invention described above, neither the balance sleeve 9 nor the balance bush 10 is exposed to the fluid passage 12 in the sliding portion on the anti-suction side, and rotates at high speed together with the main shaft 6. The balance collar 11 separates the fluid from the balance sleeve 9.
In addition, even if the fluid contains impurities such as solid particles, local fluid pressure generated as the balance collar 11 rotates is prevented. These functions work together to effectively prevent foreign matter from entering the sliding surfaces of the balance sleeve 9 and balance bush 10. Therefore, the balance sleeve 9
and wear of the balance bush 10, especially both 9,
The wear of the sliding surfaces of 10 is significantly reduced, which has the effect of further extending the life of this type of pump.

If necessary, the length of the balance sleeve and balance pusher can be made sufficiently large to enlarge the area of the sliding surface, and the above-mentioned effect will be more pronounced.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view schematically showing a conventional balanced multi-stage pump, Fig. 2 is an enlarged longitudinal sectional view of the non-suction side sliding part, and Fig. 3 is the main part of the first embodiment of this invention. That is, FIG. 4 is a longitudinal sectional view showing the main part of the second embodiment of this invention, and FIG. 5 is a longitudinal sectional view showing the main part of the third embodiment of this invention. It is a front view. 1, 2, 3, 4, 5... impeller, 6... main shaft, 9... balance sleeve, 10... balance pusher, 11... balance collar, 11a...
Mounting hole.

Claims (1)

[Scope of utility model registration request] The annular balance collar 11 is brought into contact with the axially inner end surface of the balance sleeve 9 on the non-suction side sliding portion so as to cover the entire surface of the inner end surface, and the mounting hole 11a is fitted into the main shaft 6. A balanced multi-stage pump characterized in that the balance collar 11 covers the inner end surface of the balance bush 10 in the axial direction.