JPH0634055A - Shaft sealing device - Google Patents

Abstract

PURPOSE:To exhibit optimal sealing performance, and save labor such as adjustment or replacement even when the rotation direction of a rotary shaft is changed. CONSTITUTION:A shaft sealing device has a fixed sealing ring 30 fixed to a casing 10, rotary sealing rings 71 and 72 installed movably in the shaft direction in rotary housings 61 and 62 fixed to a rotary shaft 50, push-pressing springs 81 and 82 to bring these respective rotary sealing rings 71 and 72 into pressure contact with the fixed sealing ring 30, inclined projections 71f and 72f formed in the respective rotary sealing rings 71 and 72 and a dynamic pressure generating groove 72c formed on a sealing surface where the respective rotary sealing rings and the fixed sealing ring are opposed to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft seal device for a rotary shaft, and more particularly to a shaft seal device for a rotary shaft that rotates in both directions, such as a pump turbine used in a pumped storage power plant.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional shaft seal device. The gland packing 22 and the intermediate ring 23 are inserted between the seal box 21 fixed to the casing 10 and the sleeve 51 of the rotary shaft 50, and the packing presser 24 is tightened by the bolt 25 to press the gland packing 22 and press the gland packing 22. The seal box 21 is closely contacted and sealed. In order to prevent foreign matter from entering the shaft sealing device, the fresh water supply device 27
From here, fresh water is pressed into the intermediate ring 23.

[0003]

The conventional shaft sealing device is as described above, but since the leakage increases due to wear of the gland packing 22 during use, the bolt 25 must be tightened each time. If it is not tightened too much, friction heat will be generated and damage will occur. In addition, there is a problem that it is necessary to replace the gland packing 22 and maintain the fresh water supply device 27. Further, when the rotation direction of the rotary shaft changes, there is a problem that the tightening degree of the gland packing 22 needs to be adjusted each time.

The present invention has been made in order to solve the above problems, and provides a shaft sealing device which always exhibits optimum sealing performance even when the rotation direction of a rotating shaft changes, and which does not require adjustment and replacement. The purpose is to

[0005]

SUMMARY OF THE INVENTION A shaft sealing device according to the present invention includes a fixed seal ring fixed to a casing and a rotating housing fixed to a rotary shaft for forward rotation and reverse rotation mounted axially movably. Rotary seal ring, a pressing spring for pressing each rotary seal ring against the fixed seal ring, an inclined projection formed on each rotary seal ring, and each rotary seal ring and the fixed seal ring face each other. And a dynamic pressure generating groove formed on the sealing surface.

[0006]

Each rotating seal ring according to the present invention is pressed by the pressing spring and comes into pressure contact with the fixed seal ring to limit fluid leakage. When the rotary shaft rotates, each rotary seal ring also rotates, and the fluid hits the slanted projection formed on each rotary seal ring, and a fluid force is generated in one rotary seal ring in the direction toward the fixed seal ring. The rotating seal ring is pressed against the fixed seal ring with the force of to seal. When the rotary shaft rotates in the opposite direction, a fluid force in the direction toward the fixed seal ring is generated in the other rotary seal ring, and the other rotary seal ring is pressed against the fixed seal ring together with the force of the pressing spring to seal. Further, in the dynamic pressure generating groove formed on the seal surface where the rotary seal ring and the fixed seal ring face each other, when the rotary shaft rotates, a dynamic pressure that tends to separate the seal surfaces is generated, and a minute seal gap is generated. Is retained. As a result, good sealing performance is exhibited with a small amount of friction.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 50 is a rotating shaft, which is a main shaft of a fluid machine such as a pump turbine in a pumped storage power plant.
Above the rotary shaft 50 is a generator or electric motor not shown, and below the rotary shaft 50 is a blade of a turbine (turbine) or pump not shown. Reference numeral 10 denotes a casing, which forms a turbine chamber or a pump chamber in which blades attached to a rotary shaft 50 rotate in the lower part of the drawing.
The shaft sealing device is provided at a position where the rotary shaft 50 penetrates the casing 10.

As shown in FIG. 1, this shaft seal device includes a fixed seal ring 30 fixed to the casing 10, an upper rotary housing 61 fixed to the rotary shaft 50 above the fixed seal ring 30, and an upper rotary ring. An upper rotary seal ring 71 provided on the housing 61 so as to be movable in the axial direction, a pressing spring 81 provided to press the upper rotary seal ring 71 against the upper surface of the fixed seal ring 30, an upper rotary housing 61 and an upper rotary ring. An O-ring 91 that seals the seal ring 71, a lower rotary housing 62 that is fixed to the rotary shaft 50 below the fixed seal ring 30, and a lower rotary housing that is axially movable in the lower rotary housing 62. The seal ring 72, a pressing spring 82 provided to press the lower rotary seal ring 72 against the lower surface of the fixed seal ring 30, And an O-ring 92 for sealing between the housing 62 and the lower rotary seal ring 72.

As shown in FIG. 1, the fixed seal ring 30.
Is a perforated thick circular plate through which the rotary shaft 50 passes, and the outer periphery of the fixed seal ring 30 sandwiches the O-ring 35, a gasket, and the like with the casing 10, and tightly attaches to the casing 10 with the mounting bolts 34. It is fixed. The rotary housing 6 is provided above and below the fixed seal ring 30.
1 and 62 are fixedly provided to the rotary shaft 50 so as to face the fixed seal ring 30. The rotary housings 61 and 62 are formed in a stepped cylindrical shape having a small-diameter cylindrical portion fitted on the rotary shaft 50 and a large-diameter cylindrical portion fitted on the rotary seal rings 71, 72, respectively. The rotary housings 61 and 62 are small-diameter cylindrical parts, and are tightly fixed to the rotary shaft 50 with a set screw 64 sandwiching an O-ring 65. Rotating seal ring 71
Reference numerals 72 and 72 each have a cylindrical shape having a collar-shaped portion, and are formed so as to be fitted in the rotary housings 61 and 62 respectively so as to be movable in the axial direction. A pressing spring 8 is provided between the rotary housings 61 and 62 and the rotary seal rings 71 and 72, respectively.
1, 82 are provided to press the rotary seal rings 71 and 72 toward the fixed seal ring 30, respectively.
Rotating housings 61 and 62 and rotating seal rings 71 and 7
O-rings 91 and 92 are inserted between the two and
Even if the rotary seal rings 71 and 72 move a little in the axial direction, the rotary housings 61 and 62 and the rotary seal rings 71,
A seal with 72 is maintained.

As shown in FIGS. 1 and 2, inclined protrusions 71f and 72f are formed on the outer peripheral surfaces of the flange portions of the rotary seal rings 71 and 72, respectively. As shown in FIG. 2, the inclined projections 71f and 72f are formed so as to project obliquely in the axial direction and in the shape of fins in the radial direction. Figure 2
As shown in (B), the inclined direction of the inclined protrusion 71f of the upper rotary seal ring 71 and the inclined direction of the inclined protrusion 72f of the lower rotary seal ring 72 are the same direction.

As shown in FIGS. 1 and 3, the surfaces of the rotary seal rings 71 and 72 facing the fixed seal ring 30 are seal surfaces, and the rotary seal rings 71 and 72 have dynamic pressure generating grooves on the seal surfaces. 71c and 72c are formed. As shown in FIG. 3, the dynamic pressure generating grooves 71c and 72c are formed in the seal surface in a concave wedge shape. The taper directions of the dynamic pressure generating grooves 71c and 72c are opposite to each other. If the inclined projections 71f and 72f are inclined upward to the right as shown in FIG. 2, the dynamic pressure generating grooves 71c and 72c are tapered on the left side as shown in FIG. The groove 72c is deep and shallow on the right side, and the dynamic pressure generating groove 72c is deep on the right side and is shallow on the left side. The length, width, depth, taper angle, number, etc. of the dynamic pressure generating grooves 71c and 72c may be determined by a model test or the like. Further, the above-mentioned shape, number, etc. of the dynamic pressure generating grooves 71c do not have to be the same as the above-mentioned shape, number, etc. of the dynamic pressure generating grooves 72c, and optimum sealing states for forward rotation and reverse rotation can be obtained. You may make it different so that it may be. It should be noted that both sides in the radial direction of the dynamic pressure generating grooves 71c and 72c of the rotary seal rings 71 and 72 are formed into flat seal surfaces parallel to the seal surface of the fixed seal ring 30, and these seal surfaces are smooth flat surfaces. Has been formed. Further, these planes are assembled so as to be exactly perpendicular to the axis of the rotary shaft 50.

Next, the operation of the embodiment shown in FIG. 1 will be described. When this fluid machine operates as a generator,
The blade on the lower side of the rotary shaft 50 in the figure becomes a blade of the turbine, which is rotationally driven in the forward direction by the water having the head energy passing through the water turbine chamber surrounded by the casing 10, and the upper side of the figure via the rotary shaft 50. To rotate the generator in the forward direction to generate electricity. On the contrary, when operating as a pump, the generator in the upper part of the figure becomes an electric motor and rotates in the opposite direction, and the blades in the lower part of the figure are rotationally driven in the opposite direction via the rotary shaft 50, and the casing is rotated. The water in the pump room, which is the water turbine room surrounded by 10, is pumped to a dam or the like.

In FIG. 1, when the rotary shaft 50 is not rotating, the upper rotary seal ring 71 is pushed down by the pressing spring 81, and the seal surface of the upper rotary seal ring 71 is the seal surface of the upper surface of the fixed seal ring 30. The lower rotary seal ring 72 is pushed up by the pressing spring 82, and the seal surface of the lower rotary seal ring 72 contacts and comes into close contact with the seal surface of the lower surface of the fixed seal ring 30. The close contact between the two sealing surfaces seals or limits the leakage of fluid such as water.

Next, in FIG. 1, the case where the lower blade is a blade of a water turbine and the upper blade is a generator and the rotary shaft 50 rotates in the forward direction will be described. As the rotary shaft 50 rotates, both the rotary housings 61 and 62 fixed to the rotary shaft 50 and the rotary seal rings 71 and 72 movably provided in the rotary housings 61 and 62 in the axial direction rotate together with the rotary shaft 50. . If the direction indicated by the arrow in FIGS. 2 and 3 is the forward rotation direction,
As shown in FIG. 7, the water colliding with the inclined protrusion 72f formed on the lower rotation seal ring 72 in an upwardly inclined direction is caused to change its flow upward, and as a reaction thereof, a downward fluid force is applied to the inclined protrusion 72f. This downward fluid force is applied to the pressing spring 8
The force of pushing up the lower rotating seal ring 72 of 2 is offset,
The force with which the lower rotary seal ring 72 presses against the fixed seal ring 30 is reduced. As a result, the fixed seal ring 3
Heat generation and wear of the lower seal surface and the seal surface of the lower rotary seal ring 72 are reduced.

Water leaking through the sealing surface of the lower rotary seal ring 72 and the O-ring 92 and entering the outer periphery of the rotary shaft 50, the upper rotary seal ring 71 and the fixed seal ring 30 are pressed by the pressing spring 81. The sealing surface on the top of the seal limits sealing or leakage. When the water leaking from the upper rotary seal ring 71 collects around the upper rotary seal ring 71, the water collides with the inclined projection 71f of the upper rotary seal ring 71 and the flow changes upward as shown in FIG. Made me
As a reaction, a downward fluid force is applied to the inclined protrusion 71f. This downward fluid force presses the upper rotary seal ring 71 against the fixed seal ring 30 in cooperation with the force of the pressing spring 81, and the sealing surface of the upper rotary seal ring 71 will be in close contact with the upper seal surface of the fixed seal ring 30. And
Then, as shown in FIG. 3, a dynamic pressure of the fluid is generated by the wedge action in the dynamic pressure generating groove 71c in the sealing surface of the upper rotary seal ring 71. This dynamic fluid pressure increases as the gap between the sealing surfaces of the upper rotary seal ring 71 and the fixed seal ring 30 decreases, and decreases as the gap increases. Therefore, the force of the pressing spring 81 and the inclined projection 71f are increased.
The sealing surface of the upper rotary seal ring 71, which is pushed down by the fluid force generated in the above, is held with a minute gap between the sealing surface of the upper surface of the fixed seal ring 30.
Therefore, by appropriately setting the force of the pressing spring 81, the shape and number of the inclined projections 71f, the shape and number of the dynamic pressure generating grooves 71c, and the like, the gap between the seal surfaces of the upper rotary seal ring 71 and the fixed seal ring 30 or The contact state can be set to the optimum state, and the sealing performance can be set to the optimum state.

Next, referring to FIG. 1, description will be given of a case where the upper one is used as an electric motor to reversely rotate the rotary shaft 50, and the lower blade is reversely driven to pump water as a pump. In this case, the rotation is in the direction opposite to the arrow in FIGS. 2 and 3. Since the rotation is in the opposite direction, conversely to the above, the fluid hitting the inclined protrusion 72f of the lower rotary seal ring 72 is caused to change its flow downward, and the inclined protrusion 72f is rotated.
An upward fluid force is applied to. This fluid force is applied to the pressure spring 8
The lower rotary seal ring 72 is pressed against the lower surface of the fixed seal ring 30 in cooperation with the force of 2.
The sealing surface of 1 tends to strongly contact the sealing surface of the lower surface of the fixed seal ring 30. Then, as shown in FIG. 3, a dynamic fluid force is generated in the dynamic pressure generating groove 72c of the lower rotary seal ring 72 which rotates in the direction opposite to the arrow shown in the figure, and the lower rotary seal ring 72 and the fixed seal ring 30 have lower surfaces. It tries to maintain a small gap between the sealing surfaces. By balancing these forces, the relative state between the lower rotary seal ring 72 and the lower seal surfaces of the fixed seal ring 30 can be made appropriate, and the sealing performance can be optimized. In this case, the upper rotary seal ring 71 is pressed against the fixed seal ring 30 by the pressing spring 81, and the upper rotary seal ring 71 and the fixed seal ring 30 are pressed.
The sealing surface on the top side also limits water leakage. When water collects on the outside of the upper rotary seal ring 71, the rotation is opposite to the arrow in FIG.
The fluid force applied to the inclined projection 71f of No. 1 is in the upward direction,
The upper rotation seal ring 71 is canceled by the force of the pressing spring 81.
The force of pressing against the fixed seal ring 30 is weakened, and heat generation, wear, etc. of the upper rotary seal ring 71 and the seal surface of the upper surface of the fixed seal ring 30 are reduced.

Next, another embodiment shown in FIG. 4 will be described. 4, the fixed seal ring 30 fixed to the casing 10, the rotary housings 61 and 62 fixed to the rotary shaft 50, the rotary seal rings 71 and 72 movably provided in the rotary housings 61 and 62 in the axial direction, Pressing springs 81, 8 for pressing the rotary seal rings 71, 72
The shapes, configurations, functions, etc. of the second and the like are almost the same as those of the shaft sealing device shown in FIGS. In the embodiment shown in FIG. 4, the inclined protrusions 71f and 72f are formed in a plurality of rows on the inner peripheral surfaces of the rotary seal rings 71 and 72. This inclined projection 71f
The functions and actions of 72 and 72f are similar to those described above, but if water leaking from the lower rotary seal ring 72 enters between the outer peripheral surface of the rotary shaft 50 and the inner peripheral surface of the upper rotary seal ring 71, the upper rotary seal Even if there is no water on the outside of the ring 71, the inclined projection 7
The difference is that 1f exerts its function. This embodiment is convenient when the function of the inclined protrusion 71f is to be exerted and the water outside the upper rotary seal ring 71 is desired to be removed.

In the above embodiment, the inclined protrusion 71
The upper and lower rotary seal rings 71, 72 have different inclination angles, shapes, numbers, etc., so that optimum sealing performance is exhibited for forward rotation and reverse rotation, respectively. Good to do. Further, the length, width, depth, taper angle, number, etc. of the dynamic pressure generating grooves 71c and 72c are preferably different so as to obtain an optimum state. The inclined protrusion 71f of the upper rotary seal ring 71 may be omitted depending on the conditions. Although the dynamic pressure generating grooves 71c and 72c are tapered in the above embodiment, they may be stepped (Rayleigh step).

As described with reference to FIGS. 1 to 4, the shaft sealing device is pressed by the pressing springs 81 and 82, receives the fluid force in different directions depending on the rotation direction by the inclined projections 71f and 72f, and moves on the sealing surface. Two sets of rotary seal rings 71, 72 having pressure generating grooves 71c, 72c are formed,
Since the upper rotary seal ring 71 mainly seals at the time of forward rotation, and the lower rotary seal ring 72 mainly seals at the time of reverse rotation, the strength of each pressing spring 81, 82, each inclined projection 71f, 72f. By setting the shape and the like and the shape and the like of each of the dynamic pressure generating grooves 71c and 72c according to the conditions such as the fluid pressure of the forward rotation and the reverse rotation, the fluid leakage can be performed in the optimum state even in the forward rotation and the reverse rotation. Can be restricted. If the rotary seal rings 71, 72 and the fixed seal ring 30 are made of a high hardness material, further excellent durability and the like can be obtained. In the shaft sealing device according to the present invention, since there is no portion that rubs against the rotating shaft 50,
The sleeve 51, which is conventionally required, is no longer necessary.

[0020]

As described above, according to the present invention, there are provided two sets of rotary seal rings each having a dynamic pressure generating groove on the sealing surface and an inclined projection for generating a fluid force in different directions depending on the rotating direction. Since a rotating seal ring is mainly used for sealing depending on the rotating direction, the shaft sealing device can achieve optimum sealing performance even if the rotating direction of the rotating shaft changes, and does not require adjustment and replacement. Is obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a shaft sealing device according to an embodiment of the present invention.

FIG. 2 shows the operation of the inclined projections of the rotary seal ring of the shaft sealing device according to the embodiment of the present invention, FIG.
(B) is a side view.

FIG. 3 shows the action of the dynamic pressure generating groove of the rotary seal ring of the shaft sealing device according to the embodiment of the present invention, (A) is a side view,
(B) is a sectional view.

FIG. 4 is a vertical cross-sectional view of a shaft sealing device according to another embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a conventional shaft sealing device.

[Explanation of symbols]

10: casing, 30: fixed seal ring, 50: rotary shaft, 61: upper rotary housing, 62: lower rotary housing, 71: upper rotary seal ring, 72: lower rotary seal ring, 71f, 72f: inclined projections, 71c, 72c: Dynamic pressure generating groove, 81, 82: pressing spring, 91, 92: O-ring.

Claims (1)

[Claims] 1. A fixed seal ring fixed to a casing, a rotary seal ring for forward rotation and a reverse rotation mounted on a rotary housing fixed to a rotary shaft so as to be movable in the axial direction, and each rotary seal ring. A pressure spring that presses against the fixed seal ring; an inclined projection formed on each of the rotary seal rings; and a dynamic pressure generation groove formed on a seal surface where the rotary seal ring and the fixed seal ring face each other. A shaft sealing device characterized in that