KR100658518B1 - The high pressure floating ring seals supported with bump foil - Google Patents

Abstract

A high pressure floating ring seal supported with a bump foil is provided to solve a rubbing problem of an axis and the seal and improve stability by the floating circular seal having a supporting bump. In a high pressure floating ring seal supported with a bump foil, a clamping nut(100) is installed around a rotary axis(400) of a cylindrical shape. A floating circular ring(300) moves between the clamping nut and the rotary axis in the direction of an axis, a radius and a circumference. A bump(500) supports the floating circular ring by being installed between the clamping nut and the floating circular ring. A supporting ring supports the clamping nut, the floating circular ring, and the bump at the side.

Description

High pressure floating ring seals supported with bump foil

1 is a cross-sectional view of a conventional contactless seal with a floating annular ring.

2 is a front view of a contactless seal with a bump floating annular ring of the present invention.

3 is a conceptual diagram of a bump supporting a floating ring of the present invention.

Figure 4a is a conceptual diagram showing the damping force generation of the bump before the bump of the present invention is deformed.

Figure 4b is a conceptual diagram showing the damping force generation of the bump after the bump of the present invention is deformed.

5A is a diagram showing experimental results of a contactless seal with a conventional floating annular ring.

FIG. 5B is a diagram extracting from the experiment the equivalent whirl frequency ratio of a contactless seal with a bump floating annular ring of the present invention. FIG.

6A is an embodiment of a contactless seal having a bump floating annular ring of the present invention.

FIG. 6B is an enlarged view of FIG. 6A.

The present invention relates to a high-pressure floating ring seal supported by bumps, and in particular, by using a bump-shaped object to reduce the eccentric ratio of the seal and improve the vibration damping force, thereby increasing the stability of the system. To a contactless seal.

Non-contact seals are used to increase the efficiency of the system by minimizing leakage by reducing the radial clearance between the rotating shaft and the housing. However, as the eccentricity of the seal increases, the shear frictional force of the fluid generated in the gap increases, which also acts as a cause of impairing the stability of the system.

1 is a cross-sectional view of a conventional contactless seal with a floating annular ring. As shown in FIG. 1, a non-contact seal having a floating annular ring has an axial and radial direction between the clamping nut 10 and the support ring 20 and between the clamping nut 10 and the support ring 20. And a floating ring 30 which is freely movable in the circumferential direction is inserted, and the shaft 40 is assembled to the inner surface of the seal. The clamping nut 10 limits the movement of the floating annular ring 30 in the direction of the axis 40, and the floating annular ring 30 maintains any clearance with the axis 40.

The dynamic behavior in a seal with a non-contact annular ring is affected by forces such as the shear frictional force of the fluid occurring in the gap between the inner surface of the floating ring and the outer surface of the shaft. Accordingly, the instability in the non-contact seal with the floating annular ring increases as the eccentricity of the seal increases, and this instability increases as the speed increases.

In addition, the vibration damping ability in seals with conventional non-contact floating annular rings exhibits low values compared to the increased instability at high speeds.

This instability acts as a factor that limits the efficiency of the rotating machine by limiting the maximum rotational speed of the system. Therefore, it is necessary to increase the stability in the non-contact seal having the floating annular ring in order to reduce the instability caused by the increase in speed, which is an essential factor for improving the efficiency of the rotating machine.

Accordingly, the present invention is to solve the above problems, by appropriately restraining the radial behavior of the seal to reduce the instability that increases with the increase in the eccentricity, and to improve the structure to damp the vibration in the seal to operate stably at high speed It is an object of the present invention to provide a high pressure coating ring seal that can be used.

In addition, a floating annular ring is inserted between the support ring and the clamping nut, and a bump for supporting the floating annular ring is inserted between the floating annular ring and the clamping nut to constrain the driving of the floating annular ring. It is an object of the present invention to provide a high pressure coating ring seal that allows the eccentricity to be properly maintained and generates friction between the bump and the clamping nut.

The present invention is a cylindrical rotating shaft; A clamping nut installed around the rotating shaft; A floating annular ring moving axially, radially and circumferentially between the clamping nut and the axis of rotation; A bump installed between the clamping nut and the floating ring to support the floating ring; And a clamping nut, a floating annular ring, and a support ring in contact with the bump and supporting them on the side thereof.

Hereinafter, with reference to the accompanying drawings, the configuration and operation of the embodiment of the present invention will be described in detail.

The material of the bump used in the experiment conducted to investigate the change in the stability of the seal due to the bump, which is a key member of the present invention, is SUS301 having the following physical properties.

Density: 7800kg / m3

Modulus of elasticity: 189.6GPa

Poisson's Ratio: 0.28

In addition, the specification of the non-contact seal | sticker which has the floating annular ring of this invention is as follows.

Seal inner diameter: 53mm

Seal Height: 4.5mm

Seal Width: 8mm

Seal gap: 0.1mm

Bump Height: 0.5mm

Bump Width: 8mm

Inner diameter of clamping nut: 63mm

2 is a front view of a contactless seal with a bump floating annular ring of the present invention. As shown in FIG. 2, the non-contact seal with bump floating annular ring of the present invention includes a clamping nut 100, a support ring (not shown in FIG. 2), a floating annular ring 300, a rotating shaft 400 and It consists of a bump 500.

The rotating shaft 400 forms a cylindrical shape, and the clamping nut 100 is installed around the rotating shaft 400.

The floating annular ring 300 moves axially, radially and circumferentially between the clamping nut 100 and the rotational axis 400, with grooves formed in a plurality of rows on its inner surface to obtain a labrin effect.

The bump 500 is installed between the clamping nut 100 and the floating annular ring 300 to support the floating annular ring 300, and another bump is installed between the bump 500 and the clamping nut 100. Two types of bumps can be provided.

The support ring is in contact with the clamping nut 100, the floating annular ring 300 and the bump 500 to support them laterally.

3 is a conceptual diagram of a bump supporting a floating ring of the present invention.

As shown in FIG. 3, the bump 500 is inserted between the floating annular ring 300 and the clamping nut 100 to support the floating annular ring 300. The bump 500 supports the floating annular ring in a direction opposite to the direction of the own weight of the floating annular ring, so that the seal is used to prevent an increase in the eccentricity during the initial driving.

Figure 4a is a conceptual diagram showing the damping force generation of the bump before the bump of the present invention is deformed, Figure 4b is a conceptual diagram showing the damping force generation of the bump after the bump of the present invention is deformed. As shown in FIG. 4A, a non-contact seal with a bump floating annular ring is the initial shear of fluid in the radial direction of the seal at the gap between the inner surface of the floating annular ring 300 and the outer surface of the rotation axis 400 during initial drive. Friction force will act.

At this time, the bump 500 supporting the floating annular ring 300 is deformed as shown in FIG. 4B by the shear frictional force of the working fluid. The deformed bump 500 may generate a Coulomb friction force at the contact surface with the clamping nut 100 to improve the damping force of the bump 500.

In order to investigate the change in the stability of the seal due to the use of the bump 500, an impact test was performed on the non-contact seal having the bump floating annular ring and the non-contact seal having the floating annular ring of the present invention. In general, the equivalent whirl frequency ratio (WFR) is used as a quantitative indicator for evaluating the stability of a seal in a rotor element, which is the ratio of the force causing the instability of the seal to the force to stabilize.

Equivalent whirl frequency ratios are the stiffness coefficients (Direct stiffness, Kxx, Kyy), the cross-coupled stiffness (Kxy, Kyx), and the damping coefficient (Direct damping, Cxx, Cyy), as shown in Equations 1 and 2. , The ratio of the coupling damping coefficient (Cross-coupled, Cxy, Cyx) and the rotational speed (Ω) of the side. The bending frequency ratio extracted through the impact test is shown in FIGS. 5A and 5B. The whirling frequency ratio means that the lower the value, the higher the stability.

FIG. 5A is a diagram showing an experimental result of a non-contact seal having a conventional floating annular ring, and FIG. 5B is a diagram extracted from an experiment of an equivalent bending frequency ratio of a non-contact seal having a bump floating annular ring of the present invention. .

As shown in FIG. 5A, it can be seen that in general, a contactless seal having a conventional floating annular ring decreases in stability with increasing rotational speed of the shaft. Accordingly, it has a value of 0.0324 at 6200 rpm in the experimental conditions of 3.0 MPa, while an increase of 0.39957 at 24800 rpm.

As shown in FIG. 5B, the equivalent bending frequency ratio of the contactless seal with the bump floating annular ring has a value of 0.20165 higher than that of the contactless seal with the floating annular ring at 6200 rpm at a pressure of 3.0 MPa, There was little change in the rotational speed of the shaft, and a similar value of 0.2423 was observed at 24800 rpm. Although the figures show only results up to 24800 rpm, the contactless seal with the bump floating annular ring of the present invention has superior stability and this trend compared to the contactless seal with the floating annular ring according to the prior art. It can be seen that the more clearly appear.

FIG. 6A is an embodiment of a contactless seal having a bump floating annular ring of the present invention, and FIG. 6B is an enlarged view of FIG. 6A. As shown in FIG. 6A, a bump 500 was installed between the clamping nut 100 and the floating annular ring 300. 6B shows that a bump is inserted between the clamping nut 100 and the floating annular ring 300 to support the floating annular ring 300.

It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the technical spirit of the present invention through the above description. Therefore, the technical scope of the present invention should not be limited only to the contents described in the embodiments, but should be determined by the claims.

As described above, the high-pressure floating ring seal supported by the bump according to the present invention proposes a floating annular ring seal having a bump supporting the outer surface of the floating annular ring, thereby solving the problem of rubbing between the rotating shaft and the seal. At the same time, the stability is greatly improved, and the original structure that overcomes and overcomes the disadvantages of the existing seal can be applied to various fluid machines.

Claims (3)

Cylindrical axis of rotation; A clamping nut installed around the rotating shaft; A floating annular ring moving axially, radially and circumferentially between the clamping nut and the axis of rotation; A bump installed between the clamping nut and the floating ring to support the floating ring; And And a clamping nut, a floating annular ring, and a support ring in contact with the bump and supporting them on the side thereof. The method according to claim 1, A high-pressure coating ring seal supported by a bump, characterized in that it can be provided with another bump between the bump and the clamping nut to provide two types of bumps. The method according to claim 1, The floating annular ring is a high-pressure floating ring seal supported by a bump, characterized in that the groove is formed in a plurality of rows on its inner surface to obtain a labrinth effect.

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