JP2002323144A - Labyrinth seal for fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a labyrinth seal for a fluid machine which can provide high sealing effects as opposed to a rotor at high peripheral speed, handling a high pressure fluid. SOLUTION: A surface, including the tip end of a metallic fin 2a which is opposed to the external periphery of a rotor 1 via a fine clearance is coated with a thin coating film 3 of a fluorine-based resin, to realize improvement of corrosion resistance and reduction of an opposing clearance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a labyrinth seal for a fluid machine.

[0002]

2. Description of the Related Art In a fluid compression machine having a rotor, a metal fin having a tip opposed to an outer periphery of a rotor through a minute gap is provided in order to reduce fluid leakage from a high pressure side to a low pressure side. A labyrinth seal. The labyrinth seal is fixed and supported on a casing located on the outer periphery thereof.

[0003] The sealing effect is improved by reducing the gap between the tip of the fin of the labyrinth seal and the rotor, but the tip of the fin comes into contact with the rotor due to processing errors, assembly errors or distortion, and the rotor is damaged. There is a limit to how small you can make it to avoid inducing situations.

For this reason, the fins are formed of aluminum or an aluminum alloy, which is softer than the rotor, in case of emergency contact.

In Japanese Patent Application Laid-Open Nos. Hei 7-317913 and Hei 11-236977, a metal core plate piece is formed with a skin portion made of an elastic body such as a fluororesin or rubber, and a circle is formed on the skin portion. A labyrinth seal is described in which an annular concave or convex ridge is formed to form a labyrinth seal, or a fin itself is formed of an elastic body such as a fluororesin or rubber.

[0006]

The metal labyrinth seal is designed so that the stationary fin and the rotor on the rotating side are opposed to each other so that they basically do not contact each other. is there. If the facing gap is forcibly reduced, the fins may contact the rotor and damage the rotor.

Since aluminum and aluminum alloy are easily corroded members, if a labyrinth seal having aluminum fins is used for sealing a fluid compression machine that handles corrosive gas, the seal member is corroded and the life is shortened. Is shortened.

A fin formed of a fluorine resin having high corrosion resistance as a base material has a small ability to maintain a shape with respect to fluid pressure, and has a labyrinth seal facing a rotor rotating at a high peripheral speed of 100 m / s. Then, when the tip of the fin contacts the rotor, the tip of the fin melts (breaks)
Since the sealing performance is extremely reduced, it is difficult to reduce the gap between the tip of the fin and the rotor, and it is difficult to obtain high sealing performance.

An object of the present invention is to provide a labyrinth seal for a fluid machine capable of obtaining a high sealing effect in opposition to a rotor having a high peripheral velocity and handling a high-pressure fluid.

It is another object of the present invention to provide a labyrinth seal for a fluid machine having excellent corrosion resistance.

Still another object of the present invention is to realize a labyrinth seal for such a fluid machine at low cost.

[0012]

Means for Solving the Problems The present invention basically comprises:
A small opposing gap between the rotor and a plurality of fins made of metal (for example, aluminum or an aluminum alloy) provides a sealing effect for the rotor having a high withstand pressure and a high peripheral speed, and furthermore, a thin fluorine-based resin formed on the surface of the fin. The coating film described above increases the corrosion resistance of the fins and narrows the facing gap to further enhance the sealing performance.

[0013]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional side view of a labyrinth seal of a fluid machine showing one embodiment of the present invention.

In this embodiment, an iron rotor 1
A fin member 2 made of aluminum or an aluminum alloy, with the ends of a plurality of fins 2a opposed to the outer peripheral surface of the fin 2 via a minute gap δ, is fitted to a casing 3 of a fluid machine and supported in a stationary state. The plurality of fins 2a are connected to the rotor 1
Is formed so as to have a sawtooth-shaped cross section opposite to the above. The fin member 2 further includes a fin 2a
In this configuration, the surface including the tip end surface, which comes into contact with the fluid, is covered with a thin coating film 3 of a fluorine-based resin having high corrosion resistance.

The rotor 1 in this embodiment rotates at a peripheral speed of 100 m / s with a diameter of 200 mm. The fin member 2 has five 5 mm-high fins 2a arranged at a pitch of 5 mm, and the tip of each fin 2a faces the outer peripheral surface of the rotor 1 with a small opposing gap δ = 180 μm. . This shape is a form that achieves the sealing performance of a conventional labyrinth seal by itself,
The facing gap δ is a value that does not come into contact due to vibration (eccentricity) of the rotor 1 or normal deformation of the fin member (fin) 2.

The fin member 2 is connected to each fin 2a.
The thin coating film 3 of fluororesin covering the surface of
Formed to a thickness of This fluororesin thin coating film 3
Is formed as an enamel film by applying after spraying with a spray and then baking, so that the operation is easier and the material is inexpensive as compared with the thermal spray type coating, so that it can be formed at low cost.

The labyrinth seal of the fluid machine constructed as described above realizes a basic high pressure-resistant sealing performance between each fin 2a made of metal (aluminum or aluminum alloy) and the rotor 1 by itself, and The substantial facing gap δ ′ between the rotors 1 can be reduced by the thickness of the coating film 3 by the thin coating film 3 formed including the tip of each fin 2a (δ ′ = 180−). 60
= 120 μm), the sealing performance can be further improved.

Further, the fins 2a whose surfaces are covered with the thin coating film 3 of a corrosion-resistant fluororesin do not come into contact with the fluid and corrode, so that the fins 2a have a long life.

Since the facing gap between the outer peripheral surface of the rotor 1 and the tip of the fin 2a becomes narrower for some reason, the rotor 1 and the coating film 3 formed on the fin 2a come into contact with each other. Since only the coating film 3 is not damaged and the rotor 1 is not damaged, and the fins 2a are not damaged, a decrease in sealing performance can be reduced. Further, the damaged coating film 3 can be easily repaired by re-application.

FIG. 2 is a longitudinal sectional side view of a labyrinth seal of a fluid machine showing another embodiment of the present invention. In this embodiment, the surface of each fin, including the tip surface, which comes into contact with the fluid, is coated with a thin coating film of a fluorine-based resin having high corrosion resistance by repeated coating. Other configurations are the same as those of the above-described embodiment, and therefore, the same reference numerals are given and duplicate description will be omitted.

In this embodiment, the thin coating film 3 made of a highly corrosion-resistant fluororesin covering the surface that comes into contact with the fluid, including the tip surface of each fin 2a, is formed of two layers of fluororesin by overcoating. This is a mode constituted by the coating films 3a and 3b.

By forming the coating film 3 with such two coating films 3a and 3b, a highly reliable coating film 3 without pinholes can be formed, and the corrosion resistance can be further improved. Further, the substantial opposing gap between the tip of the fin 2a and the rotor 1 can be further reduced (δ ″ = 180).
(−120 = 60 μm), so that the sealing performance can be further improved.

Since the fluorine-based resin has a large coefficient of thermal expansion, it is necessary to form a fin using itself as a base material, or to form a thick coating film on a base material or a core metal to form a fin. This leads to a significant decrease in sealing performance due to dissolution (breakage) of the resin layer due to contact with the rotor. Therefore, in any of the embodiments, the metal fin 2a has an opposing gap necessary for avoiding contact and obtaining basic sealing performance between the tip of itself and the outer peripheral surface of the rotor 1. The fluorinated resin film 3 (3a, 3b) is thinly formed on the surface of the fin 2a so as to cover the surface of the fin 2a and improve the corrosion resistance. It is important that it works so that the gap can also be reduced.

[0025]

The present invention basically provides a sealing effect for a rotor having a high withstand pressure and a high peripheral speed by a small opposing gap between a rotor and a plurality of fins made of metal (for example, aluminum or an aluminum alloy). Further, the thin fluorinated resin coating film formed on the surface of the fin enhances the corrosion resistance of the fin and narrows the facing gap to further enhance the sealing performance.

Further, the coating film of the fluororesin on the fins can be formed at low cost by baking after coating by spraying.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a labyrinth seal of a fluid machine showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional side view of a labyrinth seal of a fluid machine showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotor, 2 ... Fin member, 2a ... Fin, 3, 3
a, 3b: coating film, 4: casing.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H022 AA02 BA06 CA33 CA51 DA14 DA19 3H040 AA01 AA07 CC01 CC04 CC11 CC14 CC16 DD01 DD07 DD36 3J042 AA03 AA04 BA01 CA10 DA01 DA20

Claims (4)

[Claims] 1. A labyrinth seal in which the tip of a metal fin is opposed to the outer periphery of a rotor via a minute gap, wherein a thin coating film of a fluororesin is formed on a surface including the tip of the fin. Labyrinth seal for fluid machinery. 2. A labyrinth seal for a fluid machine according to claim 1, wherein said fluororesin coating film is an enamel film. 3. A labyrinth seal for a fluid machine according to claim 1, wherein said fins are formed of aluminum or an aluminum alloy. 4. A labyrinth seal in which the tip of a metal fin is opposed to the outer periphery of a rotor via a minute gap, wherein the fin is formed such that the minute gap has a value that achieves basic sealing performance. A labyrinth seal for a fluid machine, wherein a thin coating film of a fluorine resin is formed on a surface including a tip of the fin.