JPS627393B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a Francis-type runner.

Francis type runners are generally used in water turbines or pump turbines, and as shown in Figures 1 to 3, a plurality of curved blades 3 are provided between a crown ring 1 and a runner band 2, It has a structure in which a plurality of fluid channels 4 are formed. The blade 3 has various dimensions depending on the capacity and design conditions of the water turbine, etc., but when used in a water turbine of a pumped storage power plant, etc., it has the following shape.
In other words, in recent years, pumped storage power plants have become increasingly high-head and large-capacity in order to improve power generation capacity, and the Francis-type runners used in the water turbines of such high-head power plants are As the speed is reduced, the height of the blade 3 is made smaller. Furthermore, in a pumped storage power plant using a reversible pump turbine, the blades 3 of the Francis type runner are formed to have a long radial length in order to improve pump performance.

However, in a Francis type runner with such a small height and long blade 3,
The fluid flow path 4 is long and narrow, making it difficult to manufacture. This is because the inner surface of the fluid channel 4 needs to be finished smooth to provide smooth flow of water, but after the crown ring 1, runner band 2, and blade 3 are integrally formed, the inner surface of the fluid channel 4 has a narrow finish. This is because it becomes impossible for a worker to enter the channel 4 and polish the inner surface smooth, and the work becomes even more difficult because the surface of the blade is formed with multiple curves. It is.

Therefore, conventionally, one of the crown ring 1 and the runner band 2 is divided into a plurality of annular members in the radial direction, and either the undivided crown ring 1 or the runner band 2 and a plurality of blades 3 are connected in advance. It was manufactured in one piece, and then one of the divided annular members was welded to the blade 3 and to each other. Figure 1 shows runner bands 2 and 3.
This figure shows a Francis-type runner manufactured by dividing into individual annular members 2a, 2b, and 2c.

This conventional method has the advantage that both the divided annular members and the other parts can be finished before being joined together. However, since the crown ring 1 or runner band 2 is thick, there is a large welding margin, and in the divided crown ring 1 or runner band 2, the annular members are circumferentially welded to each other and also to the blade 3. The drawback was that complex restraint stress was generated due to the welding process, and the amount of deformation during welding was large. In addition, in order to remove this constraint stress, the entire Francis-type runner welded together is annealed, but this heat treatment causes thermal distortion in each component.
Finishing must be done again. However, since the runner is integrally formed after this annealing treatment, the fluid flow path 4 is narrow and it is impossible for workers to enter, making it impossible to perform the desired refinishing process. The runner was manufactured to a final shape that significantly deviated from the design standard dimensions.

The present invention has been made in view of these points, and allows a worker to enter the narrow fluid flow path to accurately finish the inner surface of the channel, requires fewer manufacturing steps, is easy to work with, and meets design standard dimensions. It is an object of the present invention to provide a manufacturing method capable of manufacturing a Francis-type runner having almost the same finished dimensions.

The present invention provides at least one blade among a plurality of blades.
Every other blade is divided into a plurality of blade pieces in the radial direction, and among the divided blade pieces, at least the blade pieces excluding the innermost blade piece in the radial direction, the undivided blade, and the crown ring and a runner band are integrally formed, and the inner surface of each fluid flow path is finished to a smooth surface, and then the blade pieces that are not integrally formed are sequentially attached to the integrally formed part from the outer side in the radial direction to the inner side. The structure is such that a Francis-type runner is manufactured by joining them together and finishing the inner surface of each fluid flow path to a smooth surface.

The invention will be further described with reference to FIGS. 2-4.

2-3 illustrate a Francis type runner having an even number of blades made in accordance with the present invention. When manufacturing this runner, first, out of the six blades 5, 6, 7, 8, 9, and 10, every other blade 5, 7, and 9 are separated into three blades each in the radial direction along a dividing line 11. Pieces 5a, 5b, 5
Then, among the blade pieces, the innermost blade piece 5a, 7a, 9a in the radial direction and the blade pieces 5b, 7b, 9b adjacent to the outside thereof are divided. The removed blade pieces 5c, 7c, 9c, the undivided blades 6, 8, 10, the crown ring 1, and the runner band 2 are integrally formed, and the inner surface of the fluid flow path 4 formed inside. A worker enters each fluid flow path 4 from the outlet side opening 12 in the center and finishes it into a smooth surface. During this finishing process, six blade pieces 5a, 5b, 7a, 7b, 9a, 9
Since part b has not yet been joined, the fluid flow path 4 is wide enough for a worker to enter, and the above-mentioned finishing process can be carried out easily. After this finishing process, the inner blade pieces 5b, 7b, 9
b are positioned at appropriate positions and welded to the outer blade pieces 5c, 7c, 9c, crown ring 1, and runner band 2, and the welded portions are polished to finish the inner surface of the fluid flow path to a smooth surface. During this finishing, the innermost blade pieces 5a, 7
Since a and 9a are not yet joined, a worker can enter the fluid flow path and perform a good finishing process. Then, the innermost blade piece 5
a, 7a, and 9a are positioned at appropriate positions and welded to the adjacent blade pieces 5b, 7b, and 9b, the crown ring 1, and the runner band 2, and the inner surface of the fluid flow path is finished to be a smooth surface. Since this finishing part is located at a distance where the operator can perform the finishing process at the outlet side opening 12, the finishing process can be performed satisfactorily.

Note that if the height of the blade 1 is approximately 30 cm or more at the radially outermost inlet portion, a worker can enter the fluid flow path 4 and perform finishing work.

Also, the number of radial divisions of one blade depends on the size of the runner, the number of blades, etc.
The number may be sufficient to allow a worker to enter the fluid flow path. The number and position of the blades to be divided should be at least every other blade, and in the case of an odd number of blades, both blades 5 and 13 adjacent to one place should be divided as shown in FIG. do it. Note that all the blades may be divided.

As described above, in the method for manufacturing a Francis type runner of the present invention, every other blade among a plurality of blades is divided into a plurality of blade pieces in the radial direction, and then at least the radially innermost blade among the blade pieces is divided into a plurality of blade pieces. A blade piece with one piece removed,
The undivided blade, the crown ring, and the runner band are integrally formed, and the inner surface of the fluid flow path is finished, and then the blade pieces that are not integrally formed are attached to the integrally formed part from the outer side in the radial direction to the inner side. Since the inner surface of the fluid flow path is finished while being joined sequentially towards the end, it is extremely easy to smooth the inside of the narrow fluid flow path, and the number of welding points on the blade pieces is reduced. Since thermal deformation is suppressed by the integrally formed blades on both sides, the runner can be manufactured to finished dimensions that are almost the same as the design standard dimensions, and furthermore, the manufacturing cost of the runner can be reduced. play.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional side view of a Francis-type runner manufactured by a conventional manufacturing method, FIGS. 2 to 4 show Francis-type runners manufactured by the Francis-type runner manufacturing method of the present invention, and FIG. A longitudinal side view, FIG. 3 is a plan view with the runner band removed showing a divided state of an even number of blades, and FIG. 4 is a view similar to FIG. 3 in the case of an odd number of blades. 1... Crown ring, 2... Runner band,
4...Fluid channel, 5, 6, 7, 8, 9, 10, 1
3...Blade, 5a, 5b, 5c, 7a, 7
b, 7c, 9a, 9b, 9c, 13a, 13b,
13c...Blade piece.

Claims (1)

[Claims] 1. In a method for manufacturing a Francis-type runner, which manufactures a Francis-type runner in which a plurality of blades are provided between a crown ring and a runner band to form a plurality of fluid flow paths inside, one of the plurality of blades is Each of the blades is divided into a plurality of blade pieces in the radial direction, and then the blade pieces excluding at least the innermost blade piece in the radial direction among the blade pieces, the undivided blade, the crown ring, and the runner band are separated. and finishing the inner surface of the fluid flow path, and then joining the blade pieces that are not integrally formed to the integrally formed part sequentially from the outer side in the radial direction to the inner side, and finishing the inner surface of the fluid flow path. A method for manufacturing a Francis type runner, which is characterized by finishing processing.