JP2534738B2 - Water turbine speed governor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a water turbine speed governor, and more particularly to an improvement of a slow closing mechanism of a guide vane.

(Prior Art) Generally, the guide vanes of a water turbine are controlled to be opened and closed by a water turbine governor in order to keep the rotation speed of the water turbine constant or to adjust the output.

FIG. 2 shows a conventional water turbine speed governor of this type. When the current rotational speed of the water turbine and the guide vane opening are detected and the signals are input to the actuator 1 and the regulator 2, the proper guide vane is selected. The opening is calculated, and a signal corresponding to this is output from the regulator 2 to the actuator 1. Therefore, the converter 3 corresponding to the signal
Operates to control the flow of pressure oil to the open side port 5a or the close side port 5b of the servomotor 5 via the pressure distribution valve 4.

The servo motor 5 is opened or closed according to the movement of the pressure distributing valve 4 and the guide vanes are also opened or closed in conjunction with the movement. As a method of feeding back to the regulator 2, for example, a required number of pulleys 9 are provided between the return post 6 attached to the servo motor 5 and the fan-shaped arm 8 attached to the return shaft 7.
A wire rope 10 is used for connection.
Another fan-shaped arm 11 is attached to the return shaft 7 as shown in FIG. 2, and a weight 13 is attached to the fan-shaped arm 11 via a wire 12 so that the wire rope 10 is constantly tensioned. .

A cam 14 is attached to the other end of the return shaft 7 as shown in FIG. 2, and the cam 14 rotates in conjunction with the servo motor 5 when the guide vane is closed, and the cam of the servo motor 5 is rotated. When the opening reaches the operating opening for gentle closing, the cam 14
By this, the slow-closed pressure distributor 15 is switched, and the oil drained from the open side port 5a of the servomotor 5 is throttled by the slow-closed valve 16 located between the servomotor 5 and the pressure distributing valve 4. For this reason,
The flow rate becomes small and the closing speed of the servo motor 5 becomes slower,
The closing characteristics of the guide vane as shown by the solid line graph in FIG. 3 are obtained.

Generally, the guide vane closing time is Tc, the time during which the pressure wave reciprocates in the penstock during operation of the guide vane is Tr, the pipe length is L, the pipe flow velocity before closing the guide vane is V, and the gravity acceleration is
If g and the coefficient are K, the water pressure fluctuation ΔH when Tc> Tr is Is represented by

As is clear from the equation (1), the smaller the closing time Tc of the guide vanes, in other words, the more the guide vanes are closed, the greater the water pressure fluctuation ΔH, that is, the increase in water pressure of the iron pipe. Therefore, as shown by the solid line graph in FIG. 3, by slowly closing the guide vanes, the guide vane closing time Tc becomes a large value and the water pressure fluctuation ΔH is suppressed to a small value, so that the gentle closing mechanism is effective. I know there is.

(Problems to be Solved by the Invention) Generally, in a hydraulic machine that generates electricity and pumps in both directions like a reversible pump turbine, and tends to generate vibration, or a hydraulic machine with large drop fluctuations, When the vibration occurs, the vibration is transmitted to the servo motor 5 via the upper cover, the guide vane opening / closing mechanism parts, etc., and further transmitted to the wire rope 10 via the return post 6. Then, as shown in FIG. 4, the wire rope 10 resonates between the adjacent pulleys 9, and when the sliding movement with the pulley 9 is continued, the wire of the wire rope 10 is worn and cut and finally the wire rope 10 is removed. May be disconnected.

When the wire rope 10 is cut, the return shaft 7
Is rotated by the moment due to the weight of the weight 13, and the cam 14
Becomes a fully opened position and the slowly closed pressure distributor 15 is also held at the fully opened position, so that the slowly closed valve 16 is held in the open position by the spring 17, and the oil flow from the servo motor 5 to the pressure distributing valve 4 is
The slow closing valve 16 cannot be throttled.

On the other hand, the movement of the return shaft 7 depends on the regulator 2
The guide vane closing command is issued to return the guide vane to the guide vane opening degree before the wire rope 10 is cut, because a signal indicating that the guide vane is in the fully opened state is input. However, since the wire rope 10 is cut off, the feedback of the operation amount of the servomotor 5 is not sent to the actuator 1 side and the regulator 2 side, so that the closing command is further issued. Therefore, the third
The guide vanes are closed at a rapid closing speed, as shown by the dashed line graph in the figure.

That is, at the time of servo stroke a, the wire rope
When 10 is cut, it should be closed at the closing time Tc ′, but it will be closed at the closing time Tc ″, which causes abnormal increase in the water pressure of the iron pipe, which leads to a dangerous state of damage to the iron pipe and casing. There is a risk.

By the way, such a problem occurs in a conventional water turbine speed governor because a cam mechanism for operating a slowly closed voltage distributor is provided on a return shaft, and the operation of a servo motor is indirectly transmitted to the cam mechanism for driving. It turned out to be from.

The present invention has been made in consideration of such points,
An object of the present invention is to provide a water turbine speed governor that can surely close the servo motor gently even when the wire rope is cut.

[Structure of Invention]

(Means for Solving Problems) The present invention relates to a water turbine speed governor having a servomotor and a cam mechanism for operating a slow-closing valve that throttle-controls the amount of oil discharged to a pressure distribution valve of an actuator. A mechanical interlocking mechanism that directly operates the cam mechanism by the operation of the servo motor is provided between the motor and the cam mechanism independently of the transmission mechanism that transmits the operation amount of the servo motor to the return shaft of the actuator. It is characterized by

(Operation) In the water turbine speed governor according to the present invention, the cam mechanism for operating the slowly-closed pressure distributor is directly operated by the operation of the servo motor by the mechanical interlocking mechanism. Therefore, even if the transmission mechanism or the like that mechanically transmits the operation amount of the servo motor to the return shaft of the actuator is damaged, the servo motor can be surely closed slowly.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 is an actuator, and reference numeral 2 is a regulator. The regulator 2 is connected to a pressure distribution valve 4 via a converter 3 so as to control switching of the pressure distribution valve 4. A pressure oil tank 20 is connected to the pressure distribution valve 4 as shown in FIG. 1.
20 is connected to the open side port 5a or the close side port 5b of the servomotor 5 via the pressure distribution valve 4.

As shown in FIG. 1, between the servo motor 5 and the pressure distributing valve 4, a slow closing is performed to control the amount of oil discharged from the opening side port 5a of the servo motor 5 to the pressure distributing valve 4 when the guide vane is closed. A valve 16 is provided, and the slow closing valve 16 is switched to a side not normally throttled by an urging force of a built-in spring 17.

On the other hand, in the vicinity of the servomotor 5, as shown in FIG. 1, a slow-closed pressure distributor 15 for controlling the opening / closing of the slow-closed valve 16 is provided. It can be switched. As shown in FIG. 1, the cam 14 is connected to the servo motor 5 via a link mechanism 21, and is directly driven by the operation of the servo motor 5.

The servomotor 5 is also provided with a return post 6 as shown in FIG.
The return shaft 7 is provided with fan-shaped arms 8 and 11, respectively. The return post 6 and one fan-shaped arm 8 are connected to each other via a wire rope 10 wound around a required number of pulleys 9, and the operation amount of the servomotor 5 via the wire rope 10 is the actuator 1. It is fed back to the regulator 2. A weight 13 is attached to the other fan-shaped arm 11 via a wire 12 as shown in FIG.
It is designed to always give a constant tension to.

 Next, the operation of this embodiment will be described.

The slow closing valve 16 that controls the amount of oil discharged from the opening side port of the servo motor 5 to the pressure distributing valve 4 at the time of closing the guide vane is controlled by the pressure supplied from the pressure oil tank 20 via the slow closing pressure distributor 15. It is opened and closed by oil. The switching point of the slow closing valve 16 can be freely adjusted by shifting the cam 14 in the rotational direction or adjusting the stopper position of the slow closing valve 16.

By the way, when the wire rope 10 is broken in the state of the servo stroke a shown in FIG. 3, the weight 13 is lowered,
The governor is open-ended. Then, the closing signal is issued from the regulator 2, the pressure distribution valve 4 is lowered to the maximum according to the lowering operation of the converter 3, and the servomotor 5 performs the rapid closing operation at the first-stage closing speed.

When the opening degree of the servo motor 5 reaches the operation speed of the slow closing,
The cam 14 switches the slowly closed pressure distributor 15 and the pressure oil tank 20
The slow closing valve 16 is operated by the pressure oil from the servo motor 5
The oil drained from the open side port 5a is throttled, and the servomotor 5 is closed at the second closing speed.

It should be noted that the first-stage closing speed mainly has the meaning of suppressing an increase in the rotation of the main engine, and the second-stage closing speed has the meaning of suppressing an increase in the water pressure of the iron pipe. Since the pressure device 15 is operated, the guide vane is surely closed slowly.

Although the case where the wire rope 10 is lost has been described in the above embodiment, the present invention is not limited to this, and the slow closing valve 16 can be reliably operated in any closing operation. Further, the mechanism for directly operating the cam 14 by the operation of the servomotor 5 is not limited to the link mechanism 21, but may be another mechanical interlocking mechanism.

〔The invention's effect〕

As described above, according to the present invention, since the cam mechanism for operating the slow-closed pressure distributor is directly operated by the operation of the servo motor by the mechanical interlocking mechanism, the operation amount of the servo motor is controlled by the actuator. Even if the transmission mechanism or the like that mechanically transmits to the return shaft is damaged, the servo motor can be surely closed slowly. Therefore, there is no fear of damage to the iron pipe or the like due to increase in water pressure or adverse influence on the main engine due to increase in rotation, and the reliability of the hydraulic machine can be improved.

[Brief description of drawings]

FIG. 1 is a system diagram of a water turbine speed governor showing an embodiment of the present invention,
FIG. 2 is a system diagram showing a conventional turbine speed governor, FIG. 3 is a closing characteristic diagram of a guide vane, and FIG. 4 is an explanatory diagram showing characteristics of a wire rope. 1 ... Actuator, 2 ... Regulator, 4 ... Pressure distribution valve, 5 ... Servo motor, 5a ... Open side port, 7 ...
Return shaft, 10 …… Wire rope, 14 …… Cam,
15 …… Slowly closed pressure distributor, 16 …… Slowly closed valve, 21 …… Link mechanism.

Claims (1)

(57) [Claims] 1. A transmission mechanism for mechanically transmitting an operation amount of a servo motor to a return shaft of an actuator, a regulator for converting a displacement amount of the return shaft into an electric signal and feeding back the electric signal, and switching control by the regulator. A pressure distribution valve of an actuator, and a slow closing valve provided between the pressure distribution valve and the servomotor for controlling the amount of oil discharged from the servomotor opening side port to the pressure distribution valve at the time of closing operation of the guide vane, In a water turbine speed governor including a slow-closed pressure distributor that controls opening and closing of the slow-closed valve, and a cam mechanism that operates the slow-closed pressure distributor, the servomotor and the cam mechanism are connected to each other via a link mechanism, A water turbine speed governor characterized in that a cam mechanism is directly operated by a linear movement of a servo motor.