JP2825227B2 - U-shaped packing device for water turbine guide blade bearing - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a U-shaped packing device for a water turbine guide blade bearing. [Prior Art] Figs. 3 and 4 show a conventional example of a U-shaped packing device of a water turbine cross section and a water turbine guide blade bearing portion. As shown in FIG. 1, a U-shaped packing 1 conventionally made of cow skin is surrounded by a guide blade shaft 2 of a water turbine, a shaft cover (a lower cover 3 or an upper cover 4), and a flange of a bearing 5. And water leakage in the direction of the guide blade shaft 2
When the guide blades are fully closed, water leakage from the casing 6 to the runner 7 is sealed. In FIG. 4, reference numeral 8 denotes a rubber ring of the adapter of the U-shaped packing 1, which is provided to reduce water leakage from the casing 6 to the runner 7 when the guide blades are fully closed. Japanese Unexamined Patent Publication No. Sho 56-104166 relates to this. Reference numeral 13 denotes a groove for setting the U-time packing 1 in a stable state, which is formed on the flange of the bearing 5. [Problems to be Solved by the Invention] As shown in FIG. 4, the conventional technique uses a U-shaped packing 1 made of cowhide, so that the inner peripheral side of the U-shaped packing 1 An annular space A having a triangular cross section surrounded by the guide vane shaft 2, the flange of the bearing 5, and the U-shaped packing 1 is formed, and the U-shaped packing 1, the bearing 5 An annular space A having a triangular cross section is formed which is surrounded by the flange and the shaft portion cover 3 (4). For this reason, as shown in FIG. 5, during operation, the U-shaped packing 1 is deformed so as to fill the gap A by the water pressure P acting on its upper part. When deformed in this manner, a gap is created between the rubber ring 8 and the U-shaped packing 1, and a water pressure P is generated in this gap. Due to the water pressure P generated between the rubber ring 8 and the U-shaped packing 1, the U-shaped packing 1 is excessively pressed against the guide blade shaft 2, slides and wears. In particular, when the surface of the guide blade shaft 2 is roughened due to aging, the U-shaped packing 1 is sequentially broken as shown in FIG. The present invention has been made in view of the above points, its purpose is to improve the durability against surface roughness due to aging of the sliding portion of the guide blade shaft, and to improve the water sealing, and, It is an object of the present invention to provide a U-shaped packing of a water turbine guide vane bearing portion which can be installed in existing water turbine equipment and has excellent interchangeability. Means for Solving the Problems In order to achieve the above object, the present invention provides a packing having a U-shaped cross section in a packing chamber surrounded by a guide blade shaft of a water turbine, a flange of the bearing thereof, and a shaft cover. A U-shaped packing device of a water turbine guide blade bearing portion for sealing pressure water passing through the outer peripheral surface of the guide blade shaft, wherein the U-shaped packing is made of nitrile rubber, and the bearing is provided on an outer surface thereof. The flange formed on the bearing, the corner formed by the two surfaces of the guide vane shaft, the flange formed on the bearing, and the two surfaces of the shaft cover, while leaving an arcuate surface to be fitted in the groove for the packing set provided on the flange. The molded body had an unequal thickness structure in which a part of the wall thickness was increased outward so as to fill the corner formed by the method. Here, the reason why the material of the U-shaped packing is made of nitrile rubber is that the U-shaped packing which is superior in abrasion resistance to cowhide and has an unequal thickness structure according to the present invention can be easily manufactured (cowhide leather). A U-shaped packing made of the same cannot have the above-mentioned unequal thickness structure). [Operation] According to the above configuration, a part of the thickness of the U-shaped packing is formed by the two surfaces of the flange of the bearing and the guide blade shaft, and the two surfaces of the flange of the bearing and the shaft cover. Is formed from the beginning of the setting, so that the annular space having a triangular cross-section (that is, the packing, the guide vane shaft, the bearing flange and the packing, the shaft cover, and the bearing flange formed by the packing, the shaft flange, and the packing) which existed in the conventional device. The voids A) in the shape can be eliminated. As a result, even when the water pressure P acts on the packing, a situation in which a part of the packing is deformed toward the gap A unlike the related art does not occur. According to the unequal thickness structure described above, a U-shaped surface on which the rubber ring of the auxiliary (adapter) is fitted in a tight contact state can be ensured on the inner surface of the packing. The close contact state is always maintained even if water pressure is applied to the packing by preventing packing deformation as described above. Therefore, it is possible to eliminate a situation in which the U-shaped packing is deformed and water pressure is generated between the U-shaped packing and the rubber ring as in the related art. As a result, the U-shaped packing is not excessively pressed against the guide blade shaft, and the nitrile rubber has better wear resistance than cowhide, so the U-shaped packing has a roughened surface due to aging. It has a long service life even for the sliding part of the blade shaft, and can improve the water sealing. In addition, even if a part of the thickness of the U-shaped packing is increased to the outside to fill the corner, the outer surface of the packing has an arcuate surface (R section) fitted into a packing set groove provided on the flange of the bearing. ), It is possible to replace the U-shaped packing with a conventional one while keeping the specifications of other parts (for example, guide blade shafts and bearings) in the existing water turbine equipment. Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. The same parts as those in the related art are denoted by the same reference numerals, and the description thereof will be omitted. In the present embodiment, the U-shaped packing 1a is formed of nitrile rubber, and is shaped so as to eliminate the annular space A having a triangular cross section (see FIG. 4) which existed in the conventional apparatus. That is, the U-shaped packing 1a has a flange of the bearing 5 and a guide blade shaft while leaving an arcuate surface (a U-shaped round portion) to be fitted in a groove 13 for packing set provided on the flange of the bearing 5 on its outer surface. Corner and bearing 5 formed by two surfaces 2
And a molded body having an unequal thickness structure in which a part of the wall thickness is increased outward so as to fill the corner formed by the two surfaces of the flange and the bearing cover 3 (4). Reference numerals 10 and 11 denote packing thickness increasing portions, and the increased portions form the corner portions of the packing inner diameter side and the outer diameter side, which have been a part of the radius part, until now. Also, due to the unequal thickness structure, a U-shaped surface on which the auxiliary rubber ring 8 is fitted in close contact with the packing 1a is assured as before. By setting the U-shaped packing having the above configuration in the packing chamber, the annular space A having a triangular cross section, which has existed in the conventional apparatus, is eliminated. Therefore, even when the hydraulic pressure P acts on the packing 1a, a situation in which a part of the packing 1a is deformed toward the annular gap A as in the related art does not occur. In addition, the U-shaped packing 1a always keeps the rubber ring 8 in close contact with the inner surface of the packing even if water pressure is applied to the packing by preventing deformation of the packing. Therefore, it is possible to eliminate a situation in which the U-shaped packing is deformed and water pressure is generated between the U-shaped packing and the rubber ring as in the related art. As a result, the U-shaped packing 1a is not excessively pressed against the guide blade shaft 2, and the nitrile rubber (spring hardness 90 °) has better wear resistance than cowhide. In addition, the service life of the guide blade shaft, which has been roughened due to aging, can be extended even for the sliding portion of the guide blade shaft, and the water sealing can be improved. The comparison between the water leakage characteristics of the present embodiment and the conventional example will be described later with reference to FIG. 2. Before that, however, as the reference data, the water leakage amount when only the material of the U-shaped packing is changed from the conventional example The characteristic test data will be described with reference to FIG. Seventh
The figure shows the amount of water leakage on the vertical axis and the number of operations on the guide blade axis on the horizontal axis, and the number of operations on the guide blade axis between the U-shaped packing made of cowhide and the U-shaped packing made of nitrile rubber. It is an examination of the quantitative characteristics. As is clear from the figure, the packing made of nitrile rubber is superior to the packing made of cowhide, in that the number of times of operation of the guide blade shaft, at which the amount of water leakage increases sharply, is about 10 times larger and is excellent. That is, the packing made of nitrile rubber has about 10 times the life of the packing made of cowhide. Further, even if the U-shaped packing 1a is angled by the thickened portions of the reference numerals 10 and 11, the outer surface of the packing has a round portion 12 fitted into a groove 13 for packing set provided on a flange of the bearing 5. Therefore, the U-shaped packing can be installed in existing water turbine equipment by replacing the U-shaped packing with a conventional one while keeping the specifications of other parts (for example, guide blade shafts and bearings) as they are. By the way, in the case of packing made of cowhide, since the material thereof is cowhide, it cannot be made by changing its thickness so that no gap is formed between the guide blade shaft 2 and the bearing 5, but in the case of nitrile rubber, It is easy to change the thickness so that no voids are formed. FIG. 2 is a characteristic diagram showing test results of the present embodiment and a conventional example. In the figure, the vertical axis indicates the amount of water leakage, and the horizontal axis indicates the number of times of operation of the guide blade shaft. As is clear from the drawing, the present embodiment is superior to the conventional U-shaped packing specification, in which the number of times of operation of the guide blade shaft at which the water leakage amount increases sharply is as large as 10 times or more. As described above, according to the present embodiment, the durability is improved by 10 times or more as compared with the conventional U-shaped packing. Also, compared to cow hide, nitrile rubber is a synthetic material, so dimensional accuracy is improved.
20 U-shaped packings (for one water turbine) can reduce the cost of cowhide by 70% (cowhide: 1000K ￥ / 20 → nitrile rubber: 300K ￥ / 20). Furthermore, the grease for bearing lubrication is prevented from flowing out due to the breakage of the U-shaped packing, and environmental pollution can be prevented. Further, the U-shaped packing can be applied to existing equipment as it is, and the compatibility is excellent. [Effects of the Invention] As described above, according to the U-shaped packing device of the present invention, it is possible to improve durability against surface roughness due to aged deterioration of a sliding portion of a water turbine guide blade shaft, and to improve water sealing. In addition, the existing water turbine facility can be installed as it is without inviting a design change of other parts, and the compatibility can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an embodiment of the present invention, and FIG. 3 is an enlarged vertical sectional side view corresponding to the frame A of FIG. 3, and FIG. 2 is a U-shaped packing device of a water turbine guide blade bearing according to the present invention. FIG. 3 is a vertical sectional side view of a water turbine to which the present invention is applied, and FIG. 4 is a conventional water turbine guide blade bearing U-shape. FIG. 5 is an enlarged vertical sectional side view of the packing device corresponding to the frame A in FIG. 3, FIG. 5 is a vertical sectional side view showing a state in which the U-shaped packing shown in FIG. 4 is deformed by water pressure, and FIG. FIG. 7 is a vertical cross-sectional side view showing a state in which the U-shaped packing is broken, and FIG. 7 is a characteristic diagram of a change in the amount of water leakage depending on the number of times of operation of the guide blade shaft of the U-shaped packing made of cowhide and the U-shaped packing made of nitrile rubber. . 1a ... U-shaped packing, 2 ... Water turbine guide blade shaft, 3,4 ...
… Shaft cover (lower cover, upper cover), 5… Bearing, 1
0,11 ... Packing thickness increase part, 12 ... Arc surface, 13 ...
Groove for packing set.

Continued on the front page (72) Inventor Tatsuhiko Wada 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Hideo Kimura 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Hitachi, Ltd. Hitachi Plant (72) Inventor Toshio Suzuki 3-1-1, Sachimachi, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Hitachi Plant (72) Kota Nasu 3-1-1, Sachimachi, Hitachi City, Ibaraki Prefecture No. 1 Hitachi, Ltd. Hitachi Plant (56) References JP-A-60-96680 (JP, A) JP-A-57-158983 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB) Name) F03B 11/06 F03B 11/00

Claims (1)

(57) [Claims] A water turbine that has a U-shaped packing in a packing chamber surrounded by a guide blade shaft of a water turbine, a flange of a bearing thereof, and a shaft cover, and seals pressure water passing through the outer peripheral surface of the guide blade shaft. In the U-shaped packing device of the guide vane bearing portion, the U-shaped packing is made of nitrile rubber, and the outer surface thereof has an arcuate surface that fits into a groove for a packing set provided on the flange of the bearing, A part of the wall thickness is increased outward so as to fill a corner formed by two surfaces of the bearing flange and the guide blade shaft and a corner formed by two surfaces of the bearing flange and the shaft cover. U of a water turbine guide blade bearing portion characterized by being formed of a molded body having an equal thickness structure.
-Shaped packing device.