JPH01313677A - Rotor center seal device for straight flow type hydraulic turbine generator - Google Patents

Abstract

PURPOSE:To improve combined efficiency of a hydraulic turbine generator by providing a main seal arranged approaching the internal periphery of a rotor center in its radial direction and a backup seal arranged adjacent to an external diametric side of this main seal. CONSTITUTION:A rotor center 8 is mounted to the periphery of a runner vane 4, and a main seal 9, arranged approaching the internal periphery of the rotor center 8 in its radial direction, is pressed by a spring 10 to a side of the rotor center. A backup seal 11 is arranged adjacent to an external diametric side of the main seal 9. A distance in the radial direction of a part in contact with water in a surface of the rotor center can be decreased. In this way, a straight flow type hydraulic water turbine enables its combined efficiency to be improved.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a rotor center sealing device for sealing a straight flow type water turbine/generator to prevent water from leaking from the water turbine side to the generator side.

[Conventional technology]

The straight flow type water turbine/generator is an axial flow water turbine/generator with a horizontal shaft that is applied to locations with a low head of about 25 m or less and a large flow rate, and has 3 to 5 runner blades. FIG. 2 is a schematic vertical sectional view of a straight flow type water turbine/generator, and FIG. 3 is a view taken in the direction of arrow A in FIG. In FIG. 2, a runner boss 3 is provided downstream of the valve 1 in the waterway, and a launch vane 4 is movably attached to the runner boss 3. This lunch feather 4
A generator rotor 5 is attached to the outer periphery of the generator via a rotor center, and a generator stator 2 is attached opposite to the generator rotor 5. Since the generator rotor 5 rotates, it is separated from the water turbine casing 6, which is a stationary part, to prevent river water from flowing into the generator through the gap between the generator rotor 5 and the casing 6 and flooding the generator. A pair of rotor center seal devices are provided on the upstream and downstream sides of the rotor center 8 attached to the outer periphery of the upholstery blade 4 in a direction perpendicular to the water flow. In FIG. 4, which shows this part in detail, a rotor center 8 is attached to the outer periphery of the runner blade 4, and a main seal 9 is built in opposite to the side surface of the rotor center 8, and a spring IO on the back side is attached to the rotor center surface. It is pressed so that uniform surface pressure is generated. Wear of the main seal 9 is reduced by supplying a small amount of pressurized water into the main seal 9 through piping so that a water film of very small thickness is formed between the main seal 9 and the rotor center surface. There is a backup seal 11 on the inner diameter side of the main seal 9 to temporarily seal water when there is an abnormality in parts around the main seal or during maintenance, and when the water turbine is stopped, compressed air is introduced from the outside through piping to seal the backup seal 11. Inflate it and bring it into close contact with the rotor center surface, sealing it with water.

[Problems to be Solved by the Invention] In the conventional rotor center seal device, the range from the inner peripheral end of the rotor center to the inner peripheral end of the main seal 9 (the fourth
The gap between the seal device and the rotor center surface (in the area indicated by ) in the figure is normally filled with water, so when the straight flow turbine/generator rotates, fluid friction occurs in this area. In the case of a straight flow water turbine/generator, the rotor center seal device 7 is located at a large diameter portion, so the circumferential speed of the rotor center surface is high, so the fluid friction loss power at the gap is 1 to 2 times the water turbine output. %, and improvements were desired in terms of effective use of hydropower energy. Fluid friction loss occurring on a rotating surface in a fluid is reduced as the difference in radius of the friction-generating portion of the rotating body is smaller, provided that the area of the rotating portion in contact with the fluid, that is, the rotational speed is the same. This invention replaces the positions of the main seal and backup seal that make up the rotor center seal device, placing the main seal close to the inner periphery of the rotor center, thereby reducing the water-contact area of the generator rotor center. An object of the present invention is to provide a rotor center seal device.

[Means to solve the problem]

This invention includes a main seal disposed close to the radially inner periphery of the rotor center so as to press the front and rear sides perpendicular to the water flow of the rotor center, and a main seal disposed adjacent to the outer radial side of the main seal. A rotor center seal device was constructed from the backup seal.

[For use]

According to the above rotor center seal device, by arranging the main seal that seals the rotor center close to the radially inner circumference of the rotor center, the radial distance of the water-contacting portion of the rotor center rotating surface is shortened, and water flows It is possible to reduce fluid friction loss that occurs on the rotating surface of the rotor center inside.

【Example】

FIG. 1 is a partial detailed view of a rotor center seal device according to an embodiment of the present invention, in which the same parts as in FIGS. 2, 3, and 4 are designated by the same numbers. In FIG. 1, a rotor center 8 is attached to the outer periphery of the runner blade 4, and a main seal 9 is disposed close to the radially inner periphery of the rotor center 8, and is pressed toward the rotor center by a spring IO. Furthermore, by supplying a small amount of pressurized water into the main seal 9 through piping, a water film with a minute thickness is formed between the main seal 9 and the side surface of the rotor center 8. Reduces wear. A backup seal 11 is adjacent to the outer diameter side of the main seal 9.
This backup seal 11 is inflated and sealed by introducing compressed air from the outside through piping when a component abnormality occurs around the main seal. By arranging the main seal 9 close to the radially inner periphery of the rotor center 8, the radial distance of the water-contacted portion on the rotor center surface can be reduced. According to this invention, it is impossible to perform maintenance and inspection around the main seal body while the water turbine is being filled, but since there are few opportunities for maintenance and inspection while the water turbine is being filled, in that case, the water turbine inlet and outlet gates are closed. There are no particular maintenance problems because maintenance work can be done by draining water from the inside.

【Effect of the invention】

According to this invention, the rotor center seal device includes a main seal disposed close to the radially inner circumference of the rotor center;
It consists of a backup seal placed adjacent to the outer diameter side of this main seal, and the radial length of the part of the rotor center that comes in contact with flowing water has been shortened, so it can be used for straight flow turbines.
Fluid friction loss around the rotor center seal device of the generator can be significantly reduced. As a result, the overall efficiency of straight flow water turbines and generators can be improved by 0.5 to 1.0% without significantly increasing equipment production costs.

[Brief explanation of the drawing]

FIG. 1 is a partial detailed view of a rotor center sealing device for a straight flow water turbine/generator according to an embodiment of the present invention, and FIG.
The figure is a conceptual diagram of a straight flow turbine/generator, Figure 3 is a view taken in the direction of arrow A in Figure 2, and Figure 4 is a partially detailed view of a conventional rotor center seal device for a straight flow turbine/generator. . 2: Generator stator, 3: Runner, 4: Runner blade, 5:
Generator rotor, 7: rotor center seal device, 8: low center, 9: main seal, 11: backup seal.

Claims (1)

[Claims] 1) A plurality of runner blades whose blade shafts are movably supported by a runner boss, an annular rotor center on the outer periphery of the runner blade, a rotor attached via the rotor center, and a fixed blade opposite to the rotor. In a straight flow type water turbine/generator equipped with a rotor center, the main seal is arranged close to the inner periphery of the rotor center in the radial direction so as to press the front and rear sides of the rotor center perpendicular to the water flow; It is characterized by comprising a backup seal disposed adjacent to the outer diameter side of the seal, and sealing the rotor center of the generator to prevent water from leaking from the water turbine side to the generator side when the main seal is broken. A rotor center seal device for straight flow water turbines and generators featuring: