JPH0721902Y2 - Once-through turbine with eddy current brake - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a once-through turbine with an eddy current brake.

B. Conventional technology Figures 5 and 6 show a conventional cross-flow type once-through turbine. As shown in both figures, a runner 3 is rotatably accommodated in a casing 2 provided in a housing 1, and an inlet pipe 4 and a draft pipe 5 are connected to these. A shaft 6 is fitted in the center of the runner 3, and both ends of the runner 3 are supported by bearings 7. Both ends of the casing 2 are closed by end brackets 8, and the shaft 6 penetrates the end brackets 8. A guide vane 9 is tiltably supported immediately in front of the runner 1.

The operation control of such a cross-flow type once-through turbine is generally to open and close the guide vanes 9 using a cover to change the flow rate to efficiently generate power. However, in developing countries or remote areas, the amount of water is abundant, but a large amount of power generation is not always required. Therefore, when it is necessary to maintain the power generation amount, that is, the current and frequency constant, the guide vane opening is kept constant, and when the required power generation amount decreases, a part of the power generated by braking in the turbine part is generated. Is trying to consume. In other words, the amount of power generation is reduced with a constant amount of water and a constant guide vane opening. Here, the brake used may be a mechanical brake, but an electric brake that does not cause wear is preferable, and an eddy current brake is used.

C. Problems to be solved by the device However, the eddy current type brake dissipates all the absorbed energy as heat, resulting in an extremely large amount of heat dissipation. For this reason, there is a problem in that the total amount of water becomes large due to the need for a cooling device and the cost becomes high.

An object of the present invention is to provide an once-through turbine with an eddy current brake that does not require a cooling device separately.

D. Means and Actions for Solving Problems In the present invention, an electromagnet is provided on the casing side to generate an eddy current in the end plate of the runner, so that the water flow effectively dissipates heat from the end plate of the runner. It will be.

E. Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Incidentally, the same parts as those of the above-mentioned conventional technique are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 1 shows an embodiment of the present invention. As shown in the figure, the present invention uses a runner 3 as a magnetic path constituent member of an eddy current brake.
It also serves as the end plate 10. That is, the end plate 10 is a disk-shaped conductor fitted on the shaft 6 on both sides of the runner 3, and supports a large number of runner vanes 11 on the outer peripheral portion thereof. Further, among the constituent members of the water turbine, a thick plate is used because it has the largest diameter and is necessary for strength. Therefore, if this end plate 10 is also used as a magnetic path constituent member,
Not only is a new magnetic path component unnecessary, it is economical, and since the braking force generated by the eddy current acts at a position with a large radius, the braking torque becomes large, and there is a fear of thermal stress. I almost never need it. Therefore, in the first embodiment shown in FIG. 1, the thickness of the end bracket 8 facing the end plate 10 with a minute gap therebetween is increased, the coil 12 is inserted, and a part of the end bracket 8 is inserted into the yoke 13a. , 13b. Therefore, when the coil 12 is energized, the magnetic flux passing through the yoke 13a penetrates the end plate 10 as shown by the arrow and the yoke 13a.
Return to b. When the runner 3 rotates in this state, an eddy current is generated in the end plate 10, and the heat is taken by the water flow. In the figure, 14 is a gland packing, 15 is a packing retainer, and 16 is a partition plate.

In the above-described embodiment, the end bracket 8 is provided with the electromagnet including the coil 12 and the yokes 13a and 13b. However, the present invention is not limited to such an embodiment, and the electromagnet includes
It suffices if it is provided at a position stationary with respect to the rotating runner 3, that is, on the casing side. For example, as in the second embodiment shown in FIG. 2, the casing 2 is extended, the coil 7 is interposed between the casing 2 and the end bracket 8, and the casing 2 and the end bracket 8 are partially connected to the yoke 18a. , 18b. Therefore, when the coil 17 is energized, the magnetic flux passing through the yoke 18a passes through the end plate 10 and returns to the yoke 18b as shown by the arrow in the figure. The eddy current is generated when the magnetic flux is cut off, as in the above-described embodiment.

Further, in the above embodiment, one electromagnet is formed for each end plate 10, but a plurality of electromagnets may be provided as in the third embodiment shown in FIG. That is, inside the end bracket 8, a plurality of electromagnets facing the end plate 10 are provided.
19 are arranged in the circumferential direction, and each electromagnet 19 includes an iron core 19a and a coil 1.
It is composed of 9b and. The direction of the magnetic flux generated by each electromagnet 19 is opposite to that of the adjacent electromagnet 19. Therefore, as shown in FIG. 4, the magnetic flux penetrating the iron core 19a of the electromagnet 19 and reaching the end plate 10 from the end bracket 8 passes through the iron core 19a of the adjacent electromagnet 19 and returns to the end bracket 8. Become.

F. Effects of the Invention As described above in detail based on the embodiments, in the present invention, the electromagnet is provided on the casing side, and the end plate of the runner is also used as the magnetic path constituent member. It is extremely economical because no member is required. Further, since the heat generated by the eddy current generated in the end plate of the runner is effectively dissipated by the water flow, no special cooling device is required, and the cost and size of the turbine as a whole are reduced.

[Brief description of drawings]

1, 2, and 3 are cross-sectional views showing the first, second, and third embodiments of the present invention, respectively, and FIG. 4 is an explanatory view showing a main part in FIG. 3, and a fifth view. FIG. 1 is a perspective view of a conventional cross-flow type once-through turbine, and FIG. 6 is a partial cross-sectional view of the cross-flow once-through turbine shown in FIG. In the drawings, 1 is a housing, 2 is a casing, 3 is a runner, 4 is an inlet pipe, 5 is a draft pipe, 6 is a shaft, 7 is a bearing, 8 is an end bracket, 9 is a guide vane, 10 is an end plate, and 11 is Runner vanes, 12, 17, 19b are coils, 13a, 13b, 18a, 18b are yokes, 14 is gland packing, 15 is packing retainer, 16
Is a partition plate, 19 is an electromagnet, and 19a is an iron core.

Claims (1)

[Scope of utility model registration request] 1. An eddy current is generated in an end plate of the runner by providing an electromagnet on the side of a casing which is stationary with respect to a rotating runner so that magnetic flux penetrates through the end plate of the runner. Once-through turbine with brake.