JPS6330500B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for cooling a bearing portion of a water turbine.

Conventionally, in a horizontal shaft water turbine, a cooling means as shown in FIG. 1 has been employed in order to cool a thrust bearing portion on which hydraulic thrust acts.

In Fig. 1, reference numeral 1 indicates the direction in which the hydraulic thrust acts, 2 indicates the main shaft, 3 indicates the thrust and guide bearing, 4 indicates the thrust bearing surface, 5 indicates the bearing support that also serves as the bearing oil tank, and 6 indicates the cooler. These are common when using the water supply pressure pump 7 and when using the pressure water from the penstock Q. Also, the first
In the figure, reference numeral 8 is a motor, 9 is a pressure reducing device for reducing high iron pipe water pressure to a water pressure suitable for bearing cooling, 1
0 indicates an automatic valve for sending cooling water to the bearings before starting the water turbine, and 11 indicates a motor.

In the cooling means shown in FIG. 1, the bearing portion 3 is cooled through oil in a bearing oil tank 5, and a cooler 6 for this oil is disposed in the bearing oil tank 5.

FIG. 2 shows another example of a bearing cooling means in a conventional water turbine, and in FIG. 2, the same reference numerals as in FIG. 1 indicate substantially the same parts. In addition, the reference numeral 12 in FIG. 2 is an oil circulation pump, 13 is a motor, and 14 is an oil circulation pump.
indicates a heat exchanger.

In the example shown in FIG. 2, the oil in the bearing oil tank 5 is circulated to the heat exchanger 14 of the oil circulation pump 12 and cooled.

By the way, in the conventional water turbine bearing cooling means as described above, in addition to the pressurizing pump 7 or the pressure reducing device 9, large-scale devices such as the automatic valve 10 are required to supply cooling water, and the overall structure of the water turbine is The disadvantages are that it is complex, expensive, and difficult to maintain.

The present invention attempts to solve the above-mentioned problems by utilizing leakage water from the balance pipes conventionally installed in water turbines as cooling water.
An object of the present invention is to provide a cooling structure for a bearing part of a water turbine, which has a simplified structure, lowers costs, and facilitates maintenance.

For this reason, the bearing cooling structure for a water turbine according to the present invention is provided with a bearing oil tank that communicates with the lubricating part of the bearing in the bearing that supports the main shaft of the water turbine, as well as inside the side cover on the runner crown side of the water turbine. A balance pipe is provided that communicates with the inside of the suction pipe of the water turbine, and a cooler for the oil is provided to cool the bearing part through the oil in the bearing oil tank, and the water passing through the balance pipe is used as cooling water. The balance tube is characterized in that the balance tube is provided with the cooler so that the balance tube passes through the cooler.

Hereinafter, a bearing cooling structure for a water turbine as an embodiment of the present invention will be explained with reference to the drawings. FIG. 3 is a longitudinal sectional view thereof, and FIG. 4 is a plan view thereof.
The main shaft 20 of the horizontal shaft water turbine is supported by a bearing portion 22 that receives hydraulic thrust 21 .

In general, a water turbine runner has a runner crown 23 side and a runner shroud 2 side, which are determined by the structure of the runner.
There is a difference in area with the 4th side.

Further, water does not easily flow on the runner crown 23 side, so the water pressure is high, and on the runner shroud 24 side, water flows easily, so the water pressure is low. That is, a difference occurs between the water pressure acting on the runner crown 23 side and the water pressure acting on the runner shroud 24 side.

Due to the above-mentioned difference in area and water pressure, a hydraulic thrust acts from the runner crown 23 side to the runner shroud 24 side, so in order to reduce this hydraulic thrust, the inside of the side cover 25 on the runner crown 23 side and the Balance pipes 27 and 28 are provided which communicate with the inside of the suction pipe 26 of this water turbine.

The bearing portion 22 is also provided with a bearing oil tank 29 that communicates with the lubricating portion of the bearing portion. A cooler 30 for cooling the oil is disposed so as to surround the wall of the bearing oil tank 29.

A cooler 30 is interposed in the middle of the balance tube 27 so that water passing through one of the balance tubes 27 passes through the cooler 30 as cooling water.

As a cooler for cooling the oil, instead of the cooler 30 described above, a coiled tube cooler like the one shown with reference numeral 6 in FIG. 1 may be provided in the bearing oil tank 29. It is also possible to provide a heat exchanger as shown by the reference numeral 14 in the figure and provide a coiled tube type cooler therein, but in either case, the cooler is interposed in the balance tube 27 and the balance tube is The water passing through 27 is used as cooling water.

In this way, in the water turbine bearing cooling structure of the present invention, by providing the balance pipe 27, the water pressure thrust 21 is reduced, and the water passing through the balance pipe 27 is used as cooling water for the cooler 30. As a result, the oil in the bearing oil tank 29 that communicates with the lubricating part of the bearing part 22 is cooled, so that the water supply pressure pump (see reference numeral 7 in Figs. 1 and 2) as in the conventional case is used.
Cooling of the bearing portion 22 is performed efficiently by a simple means without requiring an oil circulation pump (see reference numeral 12 in FIG. 2), and its maintenance is also facilitated.

In the embodiments described above, the present invention is applied to a horizontal shaft water turbine, but the present invention can also be applied to a rigid shaft water turbine.

As described in detail above, in the bearing cooling structure of the water turbine of the present invention, the flowing water inside the balance pipe provided for reducing hydraulic thrust is transferred to the oil in the bearing oil tank communicating with the lubricating part of the bearing. Since it is used as cooling water for water turbines, there is no need for pressurizing pumps, pressure reducing devices, automatic valves, motors, etc. compared to conventional methods, and the structure is greatly simplified and the area required for installing the water turbine is reduced. In addition, maintenance becomes easier, which is advantageous from an energy saving perspective.

[Brief explanation of the drawing]

1 and 2 are both longitudinal sectional views showing a bearing cooling structure of a conventional water turbine, and FIGS. 3 and 4 show a bearing cooling structure of a water turbine as an embodiment of the present invention. , FIG. 3 is a longitudinal sectional view thereof, and FIG. 4 is a plan view thereof. 20...Main shaft of horizontal shaft water turbine, 21...Hydraulic thrust,
22...Bearing portion, 23...Runner crown, 24
...Ranashi Loud, 25...Side cover,
26... Suction pipe, 27, 28... Balance pipe, 2
9...Bearing oil tank, 30...Cooler.

Claims (1)

[Claims] 1 The bearing part that supports the main shaft of the water turbine is equipped with a bearing oil tank that communicates with the lubricating part of the bearing part, and
A balance pipe is provided that communicates the inside of the side cover on the runner crown side of the water turbine with the inside of the suction pipe of the water turbine, and a cooler for the oil is provided to cool the bearing part via the oil in the bearing oil tank. A bearing cooling structure for a water turbine, characterized in that the balance pipe is interposed with the cooler so that water passing through the balance pipe passes through the cooler as cooling water.