JPH04123395U - Vertical pump labyrinth seal - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the sealing effect. [Structure] A labyrinth seal 13 having a plurality of seal fins 12 in the axial direction is fitted onto the main shaft 11, and a set screw 14 is attached.
Fix it with. In the plurality of seal fins 12, the tips of the seal fins 12A and 12B at both the upper and lower ends are bent downward toward the impeller side 18, and the flanges 19 provided on the upper surface of the seal case 16 and the lower end of the seal case 16 are bent downward toward the impeller side 18. Axial gaps 20A and 20B are formed between them. Furthermore, a radial gap 21 is formed between the other seal fins 12 and the seal case 16.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention applies to vertical mixed flow and axial flow pumps that do not have thrust bearings in the pump itself. Concerning Billinth Seal.

0002

[Conventional technology]

FIG. 2 is a sectional view of a main part of a conventional vertical shaft pump equipped with a labyrinth seal. figure 2, the main shaft 1 has a labyrinth seal having a plurality of seal fins 2 in the axial direction. The labyrinth seal 3 is fixed to the main shaft 1 with a set screw 4. There is. Further, a seal case 6 is fixed to the casing 5 with bolts 7.

0003 The labyrinth seal 3 is a non-contact type and is generally applied to high-speed shafts. A radial gap 8 is provided between the tip of the fin 2 and the seal case 6. Therefore, some leakage cannot be avoided. Moreover, the plurality of seal fins 2 are flat. They are arranged in rows and are shaped to maintain the same gap 8 between them and the seal case 6. has been completed. In addition, in FIG. 2, numeral 9 indicates the drive machine side, and 10 indicates the impeller side. .

0004

[Problem that the idea aims to solve]

However, the shaft of vertical mixed flow and axial flow pumps that do not have a thrust bearing in the pump itself The thrust is supported by the driven gear when a driving machine or gearing is involved. be done.

[0005] During operation, the long pump main shaft 1 is driven by thrust acting on an impeller (not shown). Although the gap 8 is elastically deformed downward, the gap 8 remains unchanged. For this reason, conventionally, the load As the discharge pressure increases, the amount of leakage from the labyrinth seal 3 increases. there was. Also, the gap 8 between the tip of the seal fin 2 and the seal case 6 is all radius The sealing effect was insufficient because the seals were arranged in the same direction.

[0006] The present invention was devised to solve the problems of the conventional technology. The purpose is to provide a labyrinth seal for vertical shaft pumps that improves the sealing effect. Ru.

[0007]

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention has developed a vertical shaft pump with a fixed main impeller. A labyrinth seal that is fitted onto a shaft and has multiple seal fins in the axial direction. bend the tips of the seal fins at both the upper and lower ends downwards toward the impeller, and then and the other seal fins and the seal case. A radial gap is formed between the two.

[0008]

[Effect]

According to the above means, as the load increases and the discharge pressure increases, the pump main The shaft elastically deforms downward toward the impeller. At this time, remove the seal fins at both the upper and lower ends. The axial clearance is reduced. Also, it flows out from the axial gap of the seal fin at the bottom end. The leaked water collides with the inner circumference of the seal case and leaks out from the radial gap in the last row. The water impinges on the sidewalls of the sealing fins at the top end. This reduces the velocity energy of leakage water. lugi disappears and the amount of leakage decreases.

[0009]

【Example】

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG. Figure 1 shows the book FIG. 2 is a sectional view of a main part of a vertical shaft pump equipped with a labyrinth seal according to an embodiment.

0010 In FIG. 1, a main shaft 11 to which an impeller (not shown) is fixed has a plurality of A labyrinth seal 13 having seal fins 12 is fitted, and the labyrinth seal 13 has seal fins 12 of The bearing seal 13 is fixed to the main shaft 11 with a set screw 14. Also, the circumference of the main shaft 11 A seal case 16 is fixed with bolts 17 to the casing 15 located in the surrounding area. There is.

[0011] In the seal fins 12, the seal fins 12 located at both the upper and lower ends The tips of A and 12B are bent downward toward the impeller side 18, and the seal case 16 and the collar 19 provided at the lower end of the seal case 16 in the axial direction. Gaps 20A and 20B are formed. In addition, other seal fins 12 and seal case The radial gap 21 between the base and the base 16 has the same structure as the conventional one. In addition , 22 indicates the driving machine side.

0012 Now, with vertical shaft pumps, as the load increases and the discharge pressure increases, the longer the The pump main shaft 11 is elastically deformed downward toward the impeller side 18. At this time, both the upper and lower ends The axial clearances 20A, 20B between the seal fins 12A, 12B are reduced. Also, below Leakage water flowing out from the axial gap 20B of the seal fin 12B at the end is drained into the seal case. The leakage water that collides with the inner periphery of the space 16 and flows out from the radial gap 21 of the last row is located at the upper end. collides with the side wall of the seal fin 12A. This reduces the velocity energy of the leaked water. disappears, and the amount of leakage decreases.

[0013]

[Effect of the idea]

As mentioned above, according to the labyrinth seal of the vertical shaft pump according to the present invention, Bend the tips of the seal fins at both the upper and lower ends downwards toward the impeller to attach the seal case. An axial clearance is formed between the seal fin and the seal case, and an axial clearance is formed between the other seal fin and the seal case. By forming a radial gap, the higher the discharge pressure, the more the axial direction of the seal The axial clearance decreases, and the lower the discharge pressure, the larger the axial clearance. Therefore, the main According to the proposed labyrinth seal, the gap is automatically adjusted depending on the pressure. Ma In addition, since gaps are provided in the axial and radial directions, the amount of leakage can be reduced and the load can be reduced. It has the excellent effect of improving the sealing effect over the entire area. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a vertical shaft pump equipped with a labyrinth seal according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a conventional vertical shaft pump equipped with a labyrinth seal.

[Explanation of symbols]

11 Main shaft 12 Seal fin 12A seal fin 12B Seal fin 13 Labyrinth Seal 14 Set screw 15 Casing 16 Seal case 17 volts 18 Impeller side 19 spit 20A Axial clearance 20B Axial clearance 21 Radial clearance 22 Drive side

Claims (1)

[Scope of utility model registration request] Claim 1: A labyrinth seal in which the impeller of a vertical pump is fitted onto a fixed main shaft and has a plurality of seal fins in the axial direction, in which the tips of the seal fins at both upper and lower ends are bent downward toward the impeller. A labyrinth seal for a vertical shaft pump, characterized in that an axial gap is formed between the seal fin and the seal case, and a radial gap is formed between another seal fin and the seal case.