JP2000018144A - Shaft sealing device for hydraulic machine and method of assembling the same - Google Patents

Abstract

(57) [Problem] To prevent a large amount of water leakage even if a ceramic seal part of a shaft water sealing device is damaged due to an unexpected cause, and to prevent a ceramic seal from drying and sliding. SOLUTION: A rotating seal ring 17a, which is provided around a rotating shaft of a hydraulic machine and is fixed to the rotating side and made of ceramics, is opposed to the rotating seal ring and is resiliently pressed by the rotating seal ring 17a. The present invention relates to a shaft water sealing device for a hydraulic machine having a stationary seal ring 17b made of ceramics held in a hydraulic system. Further, a backup seal (section δ) was further provided on the water leakage outflow side of the ceramic seal including the rotating side seal ring 17a and the stationary side seal ring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing device for a hydraulic machine, and more particularly to a shaft sealing device for sealing water leaking from a turbine or a pump, or between a rotating shaft and a stationary portion of a pump turbine. And its assembling method.

[0002]

2. Description of the Related Art FIG. 8 is a view showing a schematic configuration of a hydraulic plant having a hydraulic machine such as a general turbine or a pump turbine.
Includes a generator 3 disposed above the hydraulic machine 1.
Are connected. Water is supplied to the hydraulic machine 1 through an iron pipe connected to a water reservoir (not shown), and the runner of the hydraulic machine 1 is driven to rotate. The water that has driven the runner is rotated by the upper suction pipe 4 and the suction pipe. Water is discharged to the sewage pond 6 via the pipe runner 5.

FIG. 9 is a view showing a schematic configuration of the hydraulic machine. A steering 8 is provided on the inner periphery of a casing 7 connected to the iron pipe, and a plurality of stay vanes 8a are provided on the steering 8 in the circumferential direction. The channels are arranged and formed. An upper cover 9 and a lower cover 10 are disposed on the inner peripheral side of the steering 8 of the casing 7, and a plurality of guide vanes sandwiched between the upper cover 9 and the lower cover 10 on the inner peripheral side of the stay vane 8a. 11 are arranged in the circumferential direction.

On the other hand, a rotary shaft 2 of the hydraulic machine is provided on the central axis of the casing 7, and a runner 1 disposed between the upper cover 9 and the lower cover 10 at a lower end of the rotary shaft 2.
2 is fixed.

The water supplied to the casing 7 passes through the stay vanes 8a and the guide vanes 11, flows into the runner chamber formed by the upper cover 9 and the lower cover 10, and drives the runner 12 to rotate. Thereafter, the water is discharged to the sewage pond 6 via the upper suction pipe 4 and the suction pipe liner 5.

Meanwhile, a part of the flowing water that has passed through the guide vanes 11 tends to flow out from between the upper cover 9 and the rotating shaft 2 of the hydraulic machine through the gap 13 between the upper cover 9 and the runner 12. Between the upper cover 9 on the stationary side and the rotating shaft 2 as the rotating portion, a shaft sealing device 14 for containing running water.
Is provided. The water leaking from the shaft sealing device 14 flows over the upper cover 9, passes through a drain hole penetrating through the stay vane 8 a, and is discharged to a drain pit (not shown) by piping.

Conventionally, as the shaft water sealing device 14, a labyrinth seal type, a gland packing type, or a carbon packing type has predominantly been used. However, a non-contact type seal such as a labyrinth type has a small amount of wear and damage, but has a large amount of water leakage. In a river with a large amount of sediment, fresh water supply is required to prevent sediment wear. For the gland packing, the amount of water leakage can be reduced by tightening the packing.
There are problems such as difficulty in maintenance and wear of the rotating shaft on the other side. Further, although the carbon packing has a smaller amount of water leakage than the labyrinth seal, the carbon material, which is a material of the packing, is fragile, easily damaged, and easily worn on earth and sand.

For these reasons, in recent years, the shaft sealing device 14
As a ceramic seal was developed. FIG. 10 is a cross-sectional view showing a schematic configuration of a shaft sealing device 14 employing the above-described ceramic seal.
The rotating side seal case 16 is placed on the seal base 15 fixed to
The rotation-side seal ring 17a made of ceramics, which is a high-hardness material, is mounted on the rotation-side seal case 16a. On the other hand, on the stationary side, a water-sealing casing 18 is attached to the upper cover 9 so as to surround an annular space formed by the upper cover 9 and the rotating shaft 2. A stationary seal ring 16b made of ceramics is attached to the lower surface of the stationary seal case 16b so as to face the rotary seal ring 17a. The stationary-side seal case 16b is supported by a water-tight casing 18 with a spring 19, and the stationary-side seal ring 17b is resiliently pressed by the rotating-side seal ring 17a by the urging force of the spring 19. The running water is sealed. Further, the stationary side seal case 16b is integrally formed with a cylindrical portion inserted between the rotating shaft 2 and the water sealing casing 18, and an inner peripheral portion of the water sealing casing 18 is formed on an outer peripheral portion of the cylindrical portion. An O-ring 20 is provided to seal water with the surface.

[0009]

However, ceramic seals are excellent in abrasion resistance and durability, but ceramics, which is a brittle material, can be damaged by vibrations during the operation of the main engine and impacts when the load is cut off. Receiving and sealing performance may be impaired.

In general, ceramics are high in hardness and excellent in wear resistance, and have a very small coefficient of friction in solid contact as compared with metals. , Dry sliding is also possible. For example, in the case of an underwater bearing of a vertical shaft diffuser pump, it was conventionally necessary to supply fresh water to prevent dry sliding at the time of starting the main engine.

However, when the water level of the sewage reservoir is lower than the center of the runner, the pressure in the gap 13 between the upper cover 9 and the runner 12 becomes negative for several minutes when the main engine starts and stops, and remains in the seal portion. Water is also sucked into the gap 13 side, the shaft sealing device 14 becomes negative pressure for several minutes, and water remaining in the seal portion is also sucked into the gap 13 side, and the shaft sealing device 1
The four seal rings 17a and 17b may dry slide for several minutes and be damaged.

Furthermore, when assembling a hydraulic machine equipped with a ceramic seal type shaft sealing device, it is necessary to take care not to apply an excessive load to the ceramic component in order to prevent damage to the ceramic component during assembly. .

That is, as shown in FIG.
2. Temporarily placing the rotating part of the main engine such as the rotating shaft 2 on the lower cover 10 and assembling the stationary part located on the upper cover 9;
Finally, when the rotating part is returned to the normal position, no load other than the weight of the stationary-side seal case 16b is applied to the seal rings 17a and 17b.
6b is also temporarily placed at the lowered position, so that the O-ring 2 provided between the shaft-sealing casing 18 and the stationary-side seal case 16b when returning the main engine rotating portion to the normal position.
There is a possibility that the O-ring 20 is displaced and the O-ring 20 is bitten between the two.

In order to avoid this, the size of the stepped portion serving as the sealing surface of the O-ring 20 is increased, or the stationary side sealing case 16b can be temporarily fixed to the shaft sealing casing 18. It is necessary to prepare a proper jig.

As shown in FIG. 12, when the main engine rotating part and the upper cover 9 and, in some cases, the guide vane 11 are assembled outside the water turbine pit, and the stationary part is put on the rotating part, the suspension is suspended. If the axial gap R (FIG. 9) between the upper cover 9 and the runner 12 is larger than the movable stroke S (FIG. 10) of the stationary seal case 16b, the weight of the stationary component will be applied to the seal rings 17a and 17b. There are problems such as.

Accordingly, a first object of the present invention is to provide a shaft sealing device which prevents a large amount of water leakage even if the ceramic seal of the shaft sealing device is damaged due to unexpected causes.

A second object of the present invention is to provide a shaft sealing device which prevents the ceramic seal from drying and sliding even when the sealing pressure becomes negative.

Still another object of the third and fourth aspects of the present invention is to provide a shaft sealing device and a method for assembling the shaft sealing device, which can minimize the load applied to ceramics during assembly.

[0019]

According to a first aspect of the present invention, there is provided a rotating seal ring made of ceramics provided around a rotating shaft of a hydraulic machine and fixed to a rotating side, and opposed to the rotating seal ring. In a shaft sealing device for a hydraulic machine having a stationary seal ring made of ceramics held so as to be resiliently pressed by the rotating seal ring, leakage of water from the ceramic seal composed of the rotating seal ring and the stationary seal ring is performed. A backup seal is further provided on the side.

According to a second aspect of the present invention, there is provided a rotating seal ring made of ceramics provided around a rotating shaft of a hydraulic machine and fixed to a rotating side, and opposing the rotating side seal ring, and applying elastic pressure to the rotating side seal ring. In a shaft sealing device of a hydraulic machine having a stationary seal ring made of ceramics held in such a manner as to be provided, a water supply pipe is provided on the ceramic seal composed of the rotating seal ring and the stationary seal ring, the water supply pipe being opened on the leakage outflow side. It is characterized by having.

According to a third aspect of the present invention, there is provided a rotary seal ring provided around a rotary shaft of a hydraulic machine and made of ceramics fixed to a rotary side, and opposing the rotary seal ring. In a shaft sealing device of a hydraulic machine having a stationary seal ring made of ceramic held so as to be held, a movable stroke dimension of the stationary seal ring is larger than an axial gap dimension of a runner and an upper cover. And

According to a fourth aspect of the present invention, there is provided a rotating seal ring made of ceramics provided around a rotating shaft of a hydraulic machine and fixed to a rotating side, and opposing the rotating side seal ring. In a method of assembling a shaft sealing device for a hydraulic machine having a stationary sealing ring made of ceramic held as described above, the stationary part of the shaft sealing device is assembled after the main engine rotating part is completely assembled in a proper position. It is characterized by the following.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the drawings, the same parts as those in FIGS. 8 and 9 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a sectional view showing an embodiment of a shaft water sealing device according to the present invention.
The rotating seal ring 17a made of ceramic and mounted on the stationary seal case 16b and the stationary seal ring 17b made of ceramic mounted on the stationary seal case 16b are slidably pressed together to prevent water leakage from between the two seals. I have to do it.

The rotating side seal ring 17a and the stationary side seal ring 17b are both formed of ceramics which are high hardness materials such as silicon nitride and silicon carbide as described above, and have extremely low wear resistance and durability. Are better.
However, since this ceramic is a brittle material, there is a possibility that the ceramic may be damaged by vibration or an impact at the time of load interruption. The shaft sealing device using this ceramic seal has a small amount of water leakage if its water sealing function is working enough, but if it is damaged due to the above reasons, it will not be able to maintain a sufficient water sealing function Can also occur.

Therefore, in the present embodiment, the gap δ between the stationary side seal case 16b and the rotating shaft 2, which is a rotating part, is reduced so that a sealing effect can be exerted. Thus, even if water leaks from between the rotating side seal ring 17a and the stationary side sealing ring 17b, the gap δ between the stationary side sealing case 16b and the rotating shaft 2 is reduced to form a backup seal. Because of this, the seal is backed up at the gap,
The function as the shaft sealing device is not impaired, and the reliability can be improved.

FIG. 2 is a view showing another embodiment of the present invention, in which the inner peripheral surface of the stationary side seal case 16b, that is, the rotating shaft 2, which is the outflow side of water leakage from between the two seal rings 17a and 17b, A large number of concave grooves 2 extending in the circumferential direction
1 are formed, and a labyrinth structure is formed. Thus, even in this case, even if water leaks from between the two seal rings 17a and 17b, the water is sealed by the labyrinth structure portion including the large number of concave grooves 21, and the same effect as that shown in FIG. .

FIG. 3 is a view showing still another embodiment of the present invention, in which a labyrinth seal 22 and a gland packing 23 are provided on the upper part of a water sealing casing 18 so as to seal water with the rotating shaft 2. Are provided, and both seal rings 17 are provided.
The seals a and 17b are backed up. Therefore, in this case, it is possible to expect a sealing effect more than simply reducing the gap between the rotary shaft and the rotating shaft.

FIG. 4 is a view showing another embodiment of the present invention. A water supply pipe is provided on the upper side of the stationary side seal case 16b in the drawing, that is, on the outflow side of water leakage from between the two seal rings 17a and 17b. A connection opening 24 is provided so that water can be supplied to the outflow side of the water leakage through the water supply pipe 24.

Normally, a ceramic seal is high in hardness and excellent in wear resistance and durability, so that it can be operated without separately supplying water as long as there is water to be sealed. In a water turbine whose water level is lower than that of the runner, the sealing pressure becomes negative when the main engine is started and stopped, so that water remaining in the seal portion may be sucked into the upstream side, and the seal ring may dry slide.

When water is supplied through the water supply pipe 24 and the gap 13 between the upper cover 9 and the runner 12 becomes negative, the water is supplied to the negative pressure side through the sliding surface between the seal rings 17a and 17b. As a result, water is supplied to the seal portion, and damage to the rotating side seal ring 17a and the stationary side seal ring 17b due to dry sliding can be prevented.

Further, an automatic valve 25 is provided in the water supply system, and is opened only when the main engine is started and stopped when the gap 13 becomes a negative pressure by a timer or the like, so that water is supplied. be able to. Further, a flow detector 26 is provided in the water supply system, and the flow detector 26 checks the flow of water through the water supply pipe 24, and sets it as one of the main engine start-up conditions. The information may be output to prompt the user to check the ceramic seal.

FIG. 5 is a view showing an assembled state of the shaft sealing device of the hydraulic machine, in which the upper cover 9 and the guide vane 11, which are stationary portions, are suspended on the rotating portion, and the rotating shaft 2 is moved to a certain position. The upper cover 9 and the guide vanes 11
Is set at the proper position, and then the rotating shaft 2 and the runner 12 are further lowered slightly to set the proper position.

When the stationary part, such as the upper cover 9 and the guide vanes 11, is suspended on the rotating part, as shown in FIG. The clearance C can be secured in the axial direction of the rotating shaft 2. That is, the movable stroke dimension S (FIG. 10) of the stationary side seal ring is made larger than the axial gap dimension R (FIG. 9) between the runner 12 and the upper cover 9. Therefore, as shown in FIG. 5, the upper cover 9 is supported by the lower surface of the runner 12,
Is in contact with the lower surface of the upper cover 9,
As shown in FIG. 6, a clearance C is generated between the water sealing casing 18 and the stationary side seal case 16b.

Accordingly, when the upper cover 9 and the like are lifted, the weight of the stationary portion of the upper cover 9 and the water sealing casing 18 and the like is prevented from being applied to the seal rings 17a and 17b, and the load applied to the ceramics during assembly is minimized. can do.

FIG. 7 is a view showing an example of a method of assembling the hydraulic machine and the shaft sealing device. As shown in FIG. 7, the main unit rotating parts such as the rotating shaft 2 and the runner 12 and the upper cover 9 are provided. After being installed by a regular member, the shaft sealing device 14 is assembled. Therefore, the load acting on the rotating side and stationary side seal rings 17a, 17b during assembly can be assembled only by receiving the minimum load of only the weight of the stationary side seal case 16b and the urging force of the spring 19. It is possible to prevent the ceramic from being damaged at the time.

[0037]

As described above, according to the present invention, in a shaft sealing device using a ceramic seal, a backup seal is further provided on the leakage outflow side of the ceramic seal. Even if it is damaged due to the impact due to the interruption or other unexpected causes, and the sufficient water sealing effect cannot be exhibited, the water sealing effect can be exerted by the backup seal, and the reliability can be improved. .

In the case where the water supply pipe is opened on the water leakage outflow side of the ceramic seal, even if the sealing pressure becomes negative and the water in the ceramic seal is interrupted, the water is supplied to dry and slide. Can be prevented, and damage to the seal ring can be prevented.

Further, when the movable stroke of the stationary seal ring is made larger than the axial gap between the runner and the upper cover, the stationary part including the main engine rotating part and at least the upper cover is assembled outside the turbine pit and rotated. Even when the stationary part is put on the part and suspended, the weight of the stationary part can be prevented from being applied to the ceramic seal, and the risk of damage to the ceramic seal during assembly can be avoided.

Also, by assembling the stationary part of the shaft sealing device with the rotating part of the main engine and the stationary part including at least the upper cover in a proper position, the load acting on the seal ring during assembly is minimized. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a shaft sealing device for a hydraulic machine according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the shaft sealing device of the hydraulic machine of the present invention.

FIG. 3 is a sectional view showing still another embodiment of the shaft sealing device of the hydraulic machine of the present invention.

FIG. 4 is a cross-sectional view showing another embodiment of the shaft sealing device of the hydraulic machine of the present invention.

FIG. 5 is a diagram showing an assembled state of a hydraulic machine having the shaft water sealing device of the present invention.

FIG. 6 is an enlarged sectional view of a shaft water sealing device in FIG. 5;

FIG. 7 is a diagram showing another method of assembling the hydraulic machine having the shaft sealing device of the present invention.

FIG. 8 is a diagram showing a schematic configuration of a hydropower plant.

FIG. 9 is a sectional view showing a hydraulic machine according to the present invention.

FIG. 10 is an enlarged sectional view of a conventional ceramic shaft sealing device.

FIG. 11 is a diagram showing an example of an assembly procedure of the hydraulic machine.

FIG. 12 is a view showing another example of the assembly procedure of the hydraulic machine.

[Explanation of symbols]

 2 Rotating shaft 7 Casing 8a Stay vane 9 Upper cover 10 Lower cover 11 Guide vane 12 Runner 14 Shaft sealing device 16a Rotating side seal case 16b Stationary side seal case 17a Rotary side seal ring 17b Stationary side seal ring 18 Water seal casing 19 Spring 20 O-ring 22 Labyrinth seal 23 Gland packing 24 Water supply pipe 25 Automatic valve 26 Flow rate detector

Claims (9)

[Claims] 1. A rotating seal ring, which is provided around a rotating shaft of a hydraulic machine and is fixed to a rotating side and made of ceramics, and is opposed to the rotating seal ring and is resiliently pressed by the rotating seal ring. In a shaft sealing device of a hydraulic machine having a stationary seal ring made of held ceramics, a backup seal is further provided on the leakage outflow side of the ceramic seal composed of the rotating seal ring and the stationary seal ring. Shaft sealing device for hydraulic machinery. 2. The shaft sealing device for a hydraulic machine according to claim 1, wherein the backup seal has a small gap between the stationary-side seal case and the rotating portion. 3. The shaft sealing device for a hydraulic machine according to claim 1, wherein the backup seal has a labyrinth structure formed on a surface of the stationary seal case facing the rotation shaft. 4. The water sealing device for a hydraulic machine according to claim 1, wherein the backup seal further comprises a labyrinth seal and / or a gland packing provided on the water sealing casing. 5. A rotary seal ring, which is provided around a rotary shaft of a hydraulic machine and is fixed to the rotary side, and is made of ceramics. The rotary seal ring faces the rotary seal ring and is pressed by the rotary seal ring. In a shaft sealing device for a hydraulic machine having a stationary sealing ring made of ceramics held therein, a water supply pipe is provided on the ceramic seal made up of the rotating sealing ring and the stationary sealing ring, the water supply pipe being opened on the leakage outflow side. Shaft sealing device for hydraulic machinery. 6. The shaft sealing device for a hydraulic machine according to claim 5, wherein an automatic valve operated by a timer is provided in the water supply pipe. 7. The water sealing device for a hydraulic machine according to claim 5, wherein the water supply pipe is provided with a flow rate detecting device. 8. A rotating seal ring provided around a rotating shaft of a hydraulic machine and made of ceramics fixed to the rotating side, and opposed to the rotating side seal ring so as to be resiliently pressed by the rotating side seal ring. A hydraulic sealing device for a hydraulic machine having a stationary seal ring made of ceramics, wherein a movable stroke dimension of the stationary seal ring is made larger than an axial gap dimension between a runner and an upper cover. Shaft sealing device for machine. 9. A rotary seal ring, which is provided around a rotary shaft of a hydraulic machine and is fixed to the rotary side and made of ceramics, is opposed to the rotary seal ring, and is resiliently pressed by the rotary seal ring. A method for assembling a shaft sealing device of a hydraulic machine having a stationary sealing ring made of held ceramics, wherein the stationary part of the shaft sealing device is assembled after the main engine rotating part is completely assembled in a proper position. A method of assembling a shaft sealing device of a hydraulic machine.