JPS62294776A - Self-closing device for hydraulic turbine guide vane - Google Patents

Abstract

PURPOSE:To make a servo motor and an oil pressure supply system in small size by furnishing a counterweight having an operational force in opposite direction so as to set off the operational force of a weight on a guide vane control ring. CONSTITUTION:An iron counterweight 6 is retained magnetically by an electric magnet 5 on the condition that current is supplied to the electric magnet 5 during normal operation with normal oil pressure in an oil pressure supply system. Thereby the self-closing force by a weight 3 is set off by said counterweight 6, and if it concerned is a servo motor 2 having a capacitor to overcome the guide vane unbalance force 10, this can be opened and closed, wherein the requisite oil pressure supply system can be constructed in lightweight and small size. If oil pressure of the oil pressure supply system has gone because of any abnormality, the oil pressure supply to said servo motor 2 will drop. If this is sensed by a pressure switch and current supply to the electric magnet 5 is stopped, there will be no magnetic force to cause the counterweight 6 not retained any more to be severed from a guide vane control ring 1.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a guide vane operation method for a horizontal shaft water turbine, and is particularly useful for downsizing a servo motor and a pressure oil device. The present invention relates to a suitable water turbine guide vane self-closing device.

[Conventional technology]

In the prior art, the following methods have been used to protect water turbines in the event that a hydraulic oil system fails and oil pressure is lost.

In other words, by using a guide vane that has a hydraulic characteristic that provides a closing moment from fully closed to fully open, the guide vane will be able to act on the guide vane even if hydraulic pressure is lost and hydraulic pressure is not supplied to the guide vane servo motor. There is a method of using so-called self-closing guide vanes in which the guide vanes automatically close due to the water pressure generated.

In this method, the higher the water pressure acting on the guide vane, the more effective it is, but the lower the water pressure, the less effective it is, and it has been proven that 50 m is the lower limit.
It could not be applied below m.

Therefore, in a low head water turbine of 50 m or less, the above solution is to attach a weight with a closing moment to the guide vane operating ring, so that the guide vane has a closing moment force over the entire range from fully open to fully open. As a result, we had no choice but to use a self-closing guide vane.

In general, the opening/closing moment force of a guide vane that is subjected to water pressure has a hydraulic characteristic that the opening moment is the maximum at full opening, changes from opening moment force to closing moment force as the opening degree increases, and reaches the maximum closing moment force near full opening. It is known to exhibit

In order to achieve self-closing, the guide vane must have a closing moment force from fully closed to fully open, and the opening/closing moment force is biased toward the closing side. Therefore, a large force is required to open the guide vanes from the fully open state, and in particular, low-head water turbines of 50 m or less require a servo motor capacity that is about twice that of those without self-closing characteristics.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into consideration the compact size and light weight of the servo motor and pressure oil device, and since the servo capacity is approximately doubled, the dimensions are large, the weight is heavy, and the manufacturing cost is high.
Installation, maintenance and inspection also require a lot of time and effort, which poses the problem of being uneconomical.

The purpose of the present invention is to eliminate the problems of the prior art described above,
The objective is to make the servo motor and pressure oil device smaller and lighter, making them more economical.

[Means to solve problems]

The above purpose is to reduce the servo motor capacity by additionally installing a so-called free passage that generates a moment force with respect to the conventional water wheel guide vane operating ring, and to reduce the servo motor capacity.
This is achieved by creating a guide vane self-closing device in which the inverted weight is separated from the guide vane operating ring when the servo motor oil pressure is lost, and the guide vanes can self-close.

[Effect]

The free penetrating weight additionally installed on the guide vane operating ring has the same moment force as the weight, but the opening moment is in the opposite direction. In normal operation, the guide vanes thus function as normal guide vanes without self-closing forces.

Therefore, the servo motor capacity can be reduced to about half.

When oil pressure is lost, the free penetrating weight is separated from the guide vane operating ring, thereby functioning as a self-closing device.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In Fig. 1, a guide vane operating ring 1 provided on a horizontal shaft water turbine.
A servo motor 2. is driven by pressure oil supplied from a pressure oil device. A weight 3 which acts to self-close the guide vane operating ring 1. A weight support stand 4 that supports this weight 3 when it descends to the lowest position. The electromagnet 5 that holds the free pendulum 6, the free pendulum 6 that acts to rotate the guide vane operating ring 1 in the opening direction and has an operating force equal to that of one weight 3, and the free pendulum 6 are separated from the electromagnet 5. A hydraulic cylinder 7 is provided to soften the shock when the water wheel guide vane falls downward, and the water turbine guide vane self-closing device of the present invention is configured. Note that the guide vanes and link operation mechanism are omitted in this figure in order to explain the principle of the invention in an easy-to-understand manner.

FIG. 2 is a graph showing the relationship between the guide vane opening degree and the opening/closing moment.

The opening/closing moment characteristics of the guide vanes are shown by 10 in FIG. 2, and it has been experimentally proven that the opening moment at or near full opening becomes particularly large as the water turbine becomes a low head turbine. The self-closing property of the guide vanes is achieved by shifting the opening/closing moment in the closing direction. In other words, the movement can be achieved by appropriately setting the cross-sectional shape of the guide vane in the water flow direction and the center position of the guide vane axis.

However, in low-head water turbines, as described above, the opening moment at or near full closure is too large, so the above-mentioned measures cannot cope with it, and the help of a weight having a closing moment is required.

When the closing moment 11 of the weight is added to the opening/closing moment 10, there is a closing moment for all opening degrees from 0 to 100%, and a so-called self-closing moment 9 is formed. Since this moment 9 is greater than the frictional force, self-closing is possible.

During normal operation when the oil pressure of the pressure oil system is normal, if the electromagnet 5 is energized, the iron free penetrating weight 6 is held by the electromagnet 5 by magnetic force. As a result, the self-closing force caused by the weight 3 is canceled by the free penetrating weight 6, and the servo motor 2 that has the capacity to overcome the guide vane unbalance force 10 can be opened and closed, and the necessary pressure oil device is also lightweight and small. be able to. When the oil pressure of the pressure oil system is lost due to the occurrence of some abnormal situation, the oil pressure supplied to the servo motor 2 decreases. If this is detected by the pressure switch and the energization to the electromagnet 5 is stopped, the magnetic force disappears, so the free pendulum 6
is no longer held and is separated from the guide vane operating ring 1. In this case, only the operating force 11 of the weight 3 remains, so the guide vanes are automatically closed. In other words, it functions as a protection device for the water turbine.

Since the weight 3 and the floating weight 6 are each made of iron, the price is low despite their heavy weight, and rather than increasing the cost by adding the electromagnet 5 and hydraulic cylinder 7, the servo motor and pressure oil device capacity can be halved. Cost reduction by downsizing is much more economical.

Also, the downsizing simplifies installation, maintenance and inspection work, and has a large economic effect.

Furthermore, if the electromagnet 5 and the water turbine control power source are connected to the same system, the system will function extremely effectively as a water turbine protection device even when the water turbine control current is lost.

In addition, instead of the electromagnet 5, a latch is used to hold the loose weight 6, and a combination of a spring and a hydraulic cylinder is used to release the latch and separate the loose weight 6 when the hydraulic pressure of the pressure oil device is lost. is also possible.

Furthermore, the present invention can be applied to a self-closing device for an inlet valve, and the same effects as described above can be obtained, and the range of application is wide.

〔Effect of the invention〕

According to the present invention, the capacities of the guide vane servo motor and the pressure oil device can be reduced to about half, so there is an effect that an economical water turbine protection device can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the guide vane opening degree and guide vane opening/closing moment, and FIG. 3 is a schematic diagram of a conventional water turbine protection device. 1... Guide vane operation ring.

Claims (1)

[Scope of Claims] 1. A horizontal shaft water turbine equipped with a hydraulic servo motor for opening and closing the guide vanes and a weight on the guide vane operating ring in order to provide the guide vanes with a self-closing force; A water turbine comprising an inverted weight having an operating force in the opposite direction to counteract the servo motor, and when the hydraulic pressure of the servo motor is lost, the inverted weight is released from the operating ring and the guide vanes self-close. Guide vane self-closing device. 2. In claim 1, a reverse servo motor having the same function as the reverse weight is provided in place of the reverse weight, and when the hydraulic pressure of the servo motor is lost, the hydraulic pressure of the reverse servo motor decreases. A water turbine guide vane self-closing device characterized in that the guide vanes self-close. 3. A water turbine guide vane self-closing device according to claim 1, characterized in that the guide vane has a hydraulic characteristic of self-closing instead of the weight, thereby omitting the weight.