JPS6098268A - Shaft seal for axial-flow rotary machine - Google Patents

Abstract

PURPOSE:To improve the shaft sealing effect and prevent the vibration due to the deformation of a wheel chamber by making the tooth of a packing which surrounds the shaft of revolution in noncontact from shape memory alloy. CONSTITUTION:The tooth 3' of a packing 2 positioned both over and under or either over or under a shaft 1 of revolution, among the packings 2 divided into plural pieces in the circumferential direction is constituted of the thin pieces formed by dividing a shape memory alloy made of, e.g., Ti-Ni alloy. The teeth 3 of each rest packings 2 are made of the conventional material, and the gap in the radial direction between the shaft 1 of revolution and the tooth 3 and 3' of the packings 2 is made uniform over the whole periphery on installation. When the tooth 3' is set at a reverse metamorphosis temperature or more, the original shape is restored, and the gap between the tooth 3' and the shaft 1 of revolution is spread.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a shaft sealing device for a 6iL rotary machine that employs a 2-birinse and a 7-diamond shim packing provided in the sealing portion of a steam and gas turbine.

[Technical background of origin 1 and its problems] The problem of vibration in steam turbines occupies a large proportion of the operation and maintenance of the input source. distance.

Due to the increase in rotor type plates and the number of compartments, they are becoming more complex. Regarding this vibration, the temperature difference between the upper and lower halves of the single chamber that can sometimes occur during steam turbine operation causes a deformation called hunchback or reverse hunchback deformation of the cabin, and as a result, the backing position also becomes vertical. As a result, the rotating shaft and the backing came into contact, causing vibration and causing the rotor (two negative effects).

In other words, the shaft seal of the steam turbine is located at the outer periphery of the rotor 1 as shown in FIGS. 1 and 2.

The backing 2 is attached to the shaft backing case 4tb or the diaphragm 5, and this backing 2 is divided into a plurality of parts in the circumferential direction of the rotor 1.
'L is surrounded by -C (2).

In such a shaft sealing device for a wind turbine, the hunchback of the casing is designed to prevent vibrations caused by reverse hunchback deformation.
For example, in Japanese Patent Publication No. 54-1598, it is possible to use a 2-billin spacing whose transverse gap is larger than the horizontal gap.
It is well known as described in Publication No. 5. In this Japanese Patent Publication No. 54-15985 (2), as shown in Fig. 3, the backing 2 is eccentric mxs above and below the center point 0 of the rotor 1, and eccentric iXt is centered or below 1+41. Each draws an arc R, and the packing end 3 is the rotor 1.
(The two are arranged in a circular shape (=), and the vertical and vertical gaps V, , V, are 1.3 to 3.4 times as large as the gaps H1 and H2 in the left and right portions and the distance between #1 and rotor 1. It has a wide gap.

The eccentricities X, X2 are preferably between 0.15 and 1.84, and must be appropriately selected depending on the turbine's rigidity, severity, operating conditions, etc. That is, since the inner diameter of the backing 2 is made elliptical with respect to the vertical direction of the rotating shaft, it is possible to prevent the rotating shaft and the backing from coming into contact even if the casing deforms vertically into a hunched position (2. This makes it possible to keep the amount of leaked steam to a minimum and prevent a decrease in turbine efficiency.

However, slouching or reverse slouching deformation of the casing may cause the turbine to start up, stop, or suddenly change in load: +I!
This deformation occurs only under temporary conditions, and the deformation is not permanent and returns to its original shape over time. Assuming the worst-case scenario, setting the upper and lower parts to a wider gap than the left and right parts means that the steam, which is the working fluid, will flow from the wide gap during steady four-wheel rotation of the turbine. Or the gas is wasted (by leaking)
The high-efficiency steam and gas turbines of the energy-saving era had the drawback of being the cause of a 1 degree drop in efficiency.

[Purpose of the invention] The purpose of the present invention is to provide a rotary shaft, a labyrinth, and a
It is necessary to increase the shaft sealing by keeping the gap between the tip of the teeth and the shaft to a minimum, and to reduce the deformation of the casing (2). Provides a shaft sealing device for rotating machinery.

[Summary of the invention]

In the shaft sealing device for a trickle rotating machine according to the present invention, the entire shape of the backing is made of gold and has special ridges.
It is characterized by the fact that the teeth of the backing located above and below the rotating shaft 11111'l of the backing divided into two parts are made of shape memory alloy. be.

[Embodiments of the invention] The embodiment shown in FIG. 4 will be described below.

FIG. 4 (2) Among the backing rings 2 divided into a plurality of parts in the circumferential direction, the banking 2 located on both sides above and below the rotating shaft 1 or on one side open above or below is @a/ For example, a shape memory alloy such as a Ti-Ni alloy is divided into small pieces, and the teeth 3 of the remaining backing ring 2 are made of a conventional material. The radial clearance of ' is uniform around the entire circumference of the shaft sealing device during installation.

The shape memory alloy used for 1)li 3' of backing 2 has a shape that is higher than the martensite transformation point and is deformed in the martensite state (approximately at room temperature). However, when reheated to a temperature above the transformation point, it returns to its original shape (this is called a reverse transformation trend).
Garoshi generates a large amount of force as it recovers its original shape.
It is known that

Now, the bacteria 3' is formed in the shape of a flat plate with bent ends as shown in FIG. This is returned to a flat plate shape in the state of martensite,
As shown in Figure 5, the backing ring 2 (2) is implanted to form the tip of the tooth.The tooth 3' is formed by dividing it into strips, but this is done so that it can be easily restored to its original shape. Therefore, the number of divisions per division is determined by the radius of curvature of the tooth 3'.Furthermore, the tooth 3' is bent toward the artificial side of the steam.Then, the rotation l14111 and the backing tooth 3' come into contact. Alternatively, when the temperature of the tooth 3' reaches or exceeds the reverse transformation temperature, the tooth 3' returns to its original shape (returns to its original shape) as shown in FIG.
The gap between Hei 3' and the rotating shaft I is widened and they no longer come into contact with each other.

One way to raise the entire tooth 3' to above the reverse transformation point temperature (2) is to bring the rotation III1 and the tooth 3' into metal contact.When they come into contact, the temperature rise due to frictional heat is rapid. Therefore, the reverse deterioration of the tooth 3' will occur immediately, and this JdJ will not work for a long time, and there will be no problem with the vibration αb of the turbine operation. The method is to adjust the reverse transformation point temperature of 3' to 1.' below the degree of unmyelinating.

In this case, it goes without saying that when the turbine is operated, the field 3' will inevitably change, and there will always be a predetermined gap between the rotating shaft 1 and the backing teeth 3'.

Figure 7 (2) shows the gap diagram between the rotation mA 1 and the backing 11113, 3' of the shaft sealing device of the present invention. To return to , the radius R2 centered on the rotation axis center 0
form an arc. Figure 8 shows an embodiment of the present invention with an actual door.
A diagram of the gap between the backing teeth and the rotating shaft according to the prior art described in Japanese Patent Publication No. 54-15985 is shown superimposed with broken lines. The horizontal gap H and the vertical gap ■ are both the same. As is clear from FIG. 8, the area of as is slightly larger in the case of the present invention than in the case of the prior art, but the area of bJ is much smaller, and overall the gap is smaller in the case of the present invention. It can be seen that the area has become smaller and has been improved.

Further, in the conventional method shown in FIG. 3, there is a difficulty in machining the inner diameter of the teeth of the backing by making the center position eccentric. On the other hand, in the case of the present invention,
Since rotary cutting is only performed around the center 0 of the rotation axis, machining of the teeth of the backing is straightforward and easy.

According to the above-described embodiment of the present invention, it is an explanatory diagram showing the relationship between the backing tooth profile, the conventional rotating shaft, and the backing tooth tip in an overlapping manner.

1... Rotor 2... Backing 3.3'...backing tooth tip 4...Shaft backing case 5...Diaphragm

Claims (1)

[Claims] (1) The teeth of the backing that surround the rotating shaft in a non-contact state have a shape tI! A shaft sealing device for an axial flow rotating machine characterized by being made of an alloy. 12) A plurality of backings are provided in the circumferential direction so as to surround the rotating shaft in a non-contact state (divided into two, and this fJ
One of the several backings, one above and one below the rotating shaft.
Special feature I, characterized in that the teeth of the backing located on one side of the upper or lower side are made of a shape memory alloy.
f! f A shaft sealing device for a first-class rotating machine according to claim 1. (3) Packaging for first-class rotating machinery according to claims 1 and 2, characterized in that the shape memory alloy used in the backing is formed into a plurality of divided strips.
0 (4) Shape i Self 1 The metal has a straightness higher than the martensitic transformation point C The end is bent into a shape, and this is returned to the flat plate shape in the martensite state and used as a backing ring. A shaft sealing device for an axial flow rotating machine according to claims 2 and 3JA, characterized in that it is configured by being implanted.