JPH0321750B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a structure for cooling lubricating oil in a bearing that supports the main shaft of a water turbine used for hydroelectric power generation.

Prior Art For example, in a vertical shaft type Francis turbine used for hydroelectric power generation, a thrust bearing is provided on the generator side, while a radial bearing is provided on the main shaft of the water turbine. An example of the structure of the radial bearing is as follows. As shown in Figure 4. In other words, reference numeral 1 in FIG. 4 is a main shaft, a generator is connected to the upper side of the figure, a runner is provided on the lower side, and a sliding ring 2 is integrally attached to the middle part of this main shaft 1. It is provided. The bearing box 3 is provided so as to surround and accommodate the sliding ring 2, and therein is a white metal 4 as a bearing that slides into contact with the outer surface of the sliding ring 2.
are arranged at regular intervals in the circumferential direction, and these white metals 4 are connected to the brackets 5 and bolts 6.
It is fixed to the inner surface of the bearing box 3 by. The lubricating oil 7 is contained in the bearing box 3 to the extent that approximately half of the sliding surface between the sliding ring 2 and the white metal 4 is immersed in the lubricating oil 7, and the lubricating oil 7 is contained in the bearing box 3 to the extent that approximately half of the sliding surface between the sliding ring 2 and the white metal 4 is immersed in the lubricating oil 7. A water-cooled pipe 8 is placed in the lubricating oil 7 to prevent the temperature from rising. Therefore, the heat generated by the friction between the sliding tube 2 and the white metal 4 is carried away to the outside by continuously flowing cooling water through the water cooling tube 8, and the heat generated by the friction between the sliding tube 2 and the white metal 4 is carried away to the outside. temperature can be maintained below.

However, in the conventional cooling structure described above, since water for power generation is generally used to cool the lubricating oil 7, there is a risk that sludge or limescale may adhere to the inside of the water cooling pipe 8, causing a blockage of the water cooling pipe 8. In order to prevent such inconveniences, regular maintenance and inspection are performed. However, in the conventional structure described above, since the water cooling pipe 8 is immersed in the lubricating oil 7 in the bearing box 3, maintenance and inspection are necessary. For inspection, operations such as draining the lubricating oil 7 and removing the water-cooled pipe 8 are required, which poses a problem in that maintenance and inspection require a lot of time and effort. Furthermore, since natural water is used as the cooling water as mentioned above, its temperature may be quite low, and in such cases, condensation may occur inside the bearing box 3, resulting in water penetrating into the lubricating oil 7. Furthermore, if the water cooling pipe 8 is damaged or cracked, there is a problem that water may get mixed into the lubricating oil 7.

By the way, Japanese Unexamined Patent Publication No. 55-64166 discloses a structure using a heat pipe for cooling bearing lubricating oil in a water turbine for power generation. The proposed cooling structure has one end of the heat pipe (heat receiving part) immersed in lubricating oil, the other end (heat radiating part) partially immersed in cooling water, and the heat radiating part is heated to the temperature of the cooling water. The system is configured to use the heat of vaporization of water to cool the system. In such a lubricating oil cooling structure using a heat pipe, since the heat pipe has an extremely high heat transport ability, it is possible to efficiently carry out the heat of the lubricating oil to the outside and effectively cool the lubricating oil.

Problems to be Solved by the Invention However, the above proposed lubricating oil cooling structure using a heat pipe has the following problems.

That is, since the heat dissipation section of the heat pipe is cooled using the water temperature and the heat of vaporization of water, a part of the heat dissipation section of the heat pipe must be immersed in cooling water. As an example of a specific structure for this purpose, in the above-mentioned proposed publication, a water leakage tank is arranged below the bearing box, and the upper end of the heat pipe is used as a heat receiving part and protrudes from the bottom of the bearing box into the bearing box. At the same time, the lower end of the heat pipe is used as a heat dissipation part,
While immersing its lower end into the water leakage tank,
A structure is shown in which a wire mesh or the like having capillary action is provided above the heat radiating part, and a fan blows air onto the water sucked up from the leakage tank by the capillary action to vaporize it. However, in this structure, the heat pipe passes through the bottom of the bearing box, so in order to inspect or replace the heat pipe, it is necessary to drain the lubricating oil from inside the bearing box, which requires maintenance and inspection. It requires a lot of time and effort. In addition, the water leakage tank, fan, etc. had to be placed in a narrow space below the bearing box, which made assembly work difficult and also made maintenance and inspection difficult. Furthermore, it is extremely difficult to modify and apply the above-described structure to an existing power generation water turbine.

In addition, as another example of the specific structure in the above proposal, a cooling tank is provided on the upper surface of the bearing box, the lower part of the heat pipe is immersed in the lubricating oil in the bearing box as a heat receiving part, and the upper part of the heat pipe is immersed in the lubricating oil inside the bearing box. A structure is shown in which the heat radiating part projects from the upper surface of the bearing box into the cooling tank, and the upper end of the heat radiating part projects above the cooling tank so that cooling is performed in that part by the heat of vaporization of water. However, in this structure, a cooling tank is formed on the upper surface of the bearing box, and a heat pipe is passed from the cooling tank to the bearing box below, so water in the cooling tank may leak and enter the bearing box. There is a risk that it will enter the lubricating oil. In addition, structurally, sufficient sealing must be performed to prevent water from entering, and the heat pipe must penetrate from the bottom of the cooling tank to the top of the cooling tank, resulting in a complex structure. Therefore, it must be said that the practical value is low.

This invention was made against the background of the above circumstances, and is a bearing lubricating oil cooling structure using a heat pipe, which has a simple structure, is easy to maintain and inspect, and can be easily applied to existing power generation water turbines. The object of the present invention is to provide a cooling structure that can be easily applied just by modification.

Means for Solving the Problems This invention provides a sliding ring on the outer periphery of the intermediate portion of a vertical main shaft that rotates integrally with a runner, and a bearing that supports the main shaft via the sliding ring. In a vertical shaft power generation water turbine, the sliding ring and the bearing are housed in a bearing box, and a lubricating oil is stored in the bearing box to soak at least a part of the contact area between the sliding ring and the bearing. The lower end of the heat pipe is immersed in the lubricating oil from above the bearing box, the upper end of the heat pipe is made to protrude upward from the bearing box, and the upper end of the heat pipe is placed on the upper surface of the bearing box. The heat pipe is characterized in that a covering duct is provided and the upper end of the heat pipe is air-cooled by blowing air into the duct.

Effect When heat is generated due to friction between the sliding ring and the bearing due to the rotation of the main shaft, the temperature of the lubricating oil rises, and when the temperature exceeds the air cooling temperature in the duct, the heat pipe is immersed in the lubricating oil. The lower end of the heat pipe becomes a heating part, and the upper end of the duct that protrudes into the duct becomes a heat radiation part.As a result, the working fluid evaporates inside the heat pipe at the lower end, which is heated. The steam radiates heat after flowing to the upper end, which is the heat radiating section, and carries the heat from the lubricating oil into the duct as latent heat of the working fluid, thereby indirectly cooling the lubricating oil with air. In that case, since the heat pipe transports heat as latent heat and has an extremely high heat transport capacity, the cooling of the lubricating oil is essentially equivalent to direct air cooling, and the lubricating oil and bearings are kept at a sufficiently specified temperature. Can be maintained below.

Here, the heat pipe is inserted into the bearing box from the top side of the bearing box and its lower end is immersed in lubricating oil, so when replacing or inspecting the heat pipe, drain the oil from the bearing box. There is no need to do it,
In addition, the upper end of the bearing box that protrudes from the top side is only forcedly air-cooled in the duct, so unlike a structure in which water is cooled on the top side of the bearing box, there is no risk of water intruding into the bearing box due to cooling water leakage. There is no risk of water getting into the lubricating oil. Further, as mentioned above, the upper end of the heat pipe is simply forcedly cooled within the duct, so the structure is extremely simple. Moreover, when applying to existing power generation water turbines, all you have to do is insert the heat pipe from the top of the bearing box and install the duct on the top of the bearing surface, making it easy to modify. can be done.

Embodiments Next, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a plan view showing the arrangement of heat pipes. A sliding ring 2 is integrally provided in the middle of the vertical main shaft 1, and bearings 10 made of white metal or the like arranged at regular intervals in the circumferential direction are in contact with the outer peripheral surface of the sliding ring 2. The main shaft 1 is supported in the radical direction by fixing the bracket 10 to the inner circumferential surface of the bearing box 3 using a bracket 5 and bolts 6 attached to the bracket 5. Furthermore, lubricating oil 7 is stored in the bearing box 3 to the extent that at least a portion of the contact surface between the sliding ring 2 and the bearing 10 is immersed therein.

A large number of heat pipes passing through the upper plate of the bearing box 3 are arranged on a circumference centered on the axis of the main shaft 1. This heat pipe 11 is similar to commonly used heat pipes, in which a suitable condensable fluid is sealed as a working fluid while the inside of the sealed tube is evacuated, and a capillary pressure is generated by the heat pipe inside the sealed tube. In the illustrated example, Freon 113 (trade name) is used as the starting fluid, and a copper tube is used as the sealed tube.
As shown in an enlarged view in FIG. 3, this heat pipe 11 has a large number of heat receiving fins 12 made of copper attached to its lower end, and a number of heat radiating fins 13 made of aluminum attached to its upper end. Ori,
The heat receiving fin 12 is immersed in the lubricating oil 7,
The heat dissipation fins 13 are arranged so as to protrude above the bearing box 3, and the flange 1 provided in the middle thereof
4 to the upper plate of the bearing box 3.

Furthermore, the end of the heat pipe 11 that protrudes above the bearing box 3 is covered with an annular duct 15, as shown in FIG. 2, and a part of this duct 15 is provided with a blower 16. An exhaust hole 17 is provided at a position facing the blower 16 in the radial direction of the duct 15. Therefore, the heat pipe 11 This is an air-cooling area that cools the ends of the pipe.

In the bearing device described above, when the sliding ring 2 rotates together with the main shaft 1, heat is generated due to friction with the bearing 10, and the temperature of the lubricating oil 7 rises due to the heat. The upper end portion to which the heat dissipation fins 13 of No. 11 are attached is located in the air-cooled area within the duct 15 and is cooled to below the temperature of the lubricating oil 7. The part that becomes the heating part and is in the air cooling area becomes the heat dissipation part. Therefore, inside the heat pipe 11, the working fluid that has received heat from the lubricating oil 7 evaporates, and the vapor flows into the heat dissipation fin 1.
After flowing to the end where No. 3 is attached, it radiates heat and condenses, transporting the heat as latent heat of the working fluid. That is, the lubricating oil 7 is indirectly cooled by air via the heat pipe 11, and as a result, the lubricating oil 7 and the bearing 10 are maintained at a specified temperature or lower.

The cooling capacity of the above cooling structure is affected by the heat transfer efficiency of the heat receiving fins 12 and the heat dissipating fins 13 as well as the amount of air blown and the temperature of the air, so in order to maintain the desired cooling capacity, Regular maintenance and inspection is required, but with the cooling structure described above, all you have to do is pull out the heat pipes 11 one by one and inspect or replace them, making maintenance and inspection easy and quick. can be done. Furthermore, in the above cooling structure, since low-temperature fluid such as air is not directly introduced into the inside of the bearing box 3, there is no risk of condensation or water contamination with the lubricating oil 7. Since no cooling water is used for cooling, there is no chance of water getting mixed into the lubricating oil due to cooling water leakage. Furthermore, as the working fluid for the heat pipe 11, a fluid such as fluorocarbon that has a low boiling point and is volatile and does not contaminate the lubricating oil 7 can be used, so there is no risk of deterioration of the properties of the lubricating oil 7. This can be prevented.

Note that the present invention can be used for cooling various types of bearings other than bearings made of white metal.

Effects of the Invention As explained above, in the bearing lubricating oil cooling structure of the power generation water turbine of the present invention, the bearing lubricating oil is cooled through the heat pipe which has an extremely high heat transport capacity. Maintenance and inspection are easy because the lower end is immersed in the lubricating oil in the bearing box from above, and the upper end protrudes to the top of the bearing box and is forcedly cooled in a duct. Moreover, it is extremely simple in structure, and since no water is used to cool the heat pipe, there is no risk of cooling water getting mixed into the lubricating oil, and it can also be easily applied to existing power generation water turbines. be able to.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a plan view showing the arrangement of heat pipes, and FIG. 3 is a front view showing an example of the heat pipe.
FIG. 4 is a sectional view showing a conventional cooling structure. 1...Main shaft, 2...Sliding ring, 3...Bearing box, 7
... Lubricating oil, 10 ... Bearing, 11 ... Heat pipe, 15 ... Duct, 16 ... Blower, 17 ...
Exhaust hole.

Claims (1)

[Claims] 1. A sliding ring is provided on the intermediate outer periphery of a vertical main shaft that rotates integrally with the runner, and a bearing is provided to support the main shaft via the sliding ring, and these sliding rings and In a vertical shaft type power generation water turbine in which a bearing is housed in a bearing box and a lubricating oil is stored in the bearing box to soak at least a part of the contact area between the sliding ring and the bearing, from above the bearing box. The lower end of the heat pipe is immersed in the lubricating oil, the upper end of the heat pipe is made to protrude upward from the bearing box, and a duct is provided on the upper surface side of the bearing box to cover the upper end of the heat pipe. 1. A cooling structure for bearing lubricating oil in a water turbine for power generation, characterized in that the upper end of a heat pipe is air-cooled by blowing air into a duct.