JPS6059435B2 - Water turbine governor pressure distribution valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an improvement in a pressure distribution valve for a speed governor for a water turbine that controls guide vanes.

[Background of the invention]

The servo motor that directly operates the guide vanes is operated by pressure oil supplied from the pressure distribution valve, and the pressure distribution valve limits the allowable amount of water, that is, the allowable closing speed of the guide vanes, to a predetermined value or less in relation to the guide vane opening degree. There is a technology to do that.

To explain using the example of Fig. 1, when the servo motor opening degree y≧yA, for example, y, the maximum allowable closing speed = tan θ 1,
Further, when y<yΛ, for example, y2, the allowable maximum closing speed taneL. becomes. That is, if a closing command is given when the opening degree is y2, the guide vane can only be closed at a speed of taneL2, as shown by the dotted line. However, in view of water pressure fluctuations, it is more preferable to close the valve quickly (for example, as shown by the dotted line in FIG. 2), because it can suppress fluctuations in rotational speed during load fluctuations. Conventionally, in order to suppress the rotational speed fluctuations during load fluctuations, when the generator's disconnector trips or the stop relay is activated, the closing speed of the guide vanes is temporarily reduced via a timer circuit from that moment on. The idea is to make it faster. However, this method is only applicable in special cases where the water turbine is stopped and is not always effective. Moreover, since electric circuits such as timers are involved, reliability is also an issue. [Objective of the Invention] F. The present invention has been made in an attempt to improve the above-mentioned drawbacks, and its purpose is to reliably suppress water pressure fluctuations and water turbine rotational speed fluctuations to a small level at any guide vane opening. .

[Summary of the invention]

5 In other words, the present invention is characterized in that a valve servo motor for operating the plunger is provided in the main pressure regulating valve body integrally with the plunger, and the main pressure regulating valve body is configured to operate in the operating direction of the servo motor that drives the guide vanes to open and close. For water turbines, the oil passage has an oil passage which is switched by the plunger, the opening area of the oil passage is controlled by the position of the plunger, and the closing speed of the guide vane is controlled by the amount of oil flowing through the oil passage. In the pressure distribution valve of the speed governor, when the plunger is moved beyond a predetermined opening position of the oil passage by the valve servo motor, a switching valve 14 is provided which is operated by the movement of the valve servo motor. Accordingly, there is provided a pressure distribution valve for a water turbine speed governor that is provided with a stop piston that operates a valve servo motor to pull the plunger back within a predetermined opening position of the oil passage.

This configuration temporarily activates the servo motor rapidly without using electrical means, and then automatically operates more slowly than the rapid activation to close the guide vane. [Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

1 is a main pressure distribution valve body into which a plunger 2 is inserted so as to be movable up and down by hydraulic pressure; 3 is a valve servo motor provided integrally with the plunger 2;
A stop piece 4 is integrally fixed to the upper end of the frame with a bolt 5.

Numeral 6 is a bolt that guides the stop piece 4 and is fixed to the main pressure distribution valve body 1, and nuts 7 and 8 that limit the upward position of the stop piece 4 are fixed to this bolt 6.

Reference numeral 10 denotes a stop piston provided in an upper concave portion of the main pressure regulating valve body 1, and this stop piston 1.0 is moved up and down by hydraulic pressure using a valve and a hydraulic motor 3 as a guide.

Reference numeral 9 indicates a holding plate that limits the upward position of the stop piston 10, and reference numeral 11 indicates a bolt fixed to the upper surface of the stop piston 10 with a nut 12. limit the location.

13 is the lower surface of the stop piece 4 and the stop piston 10
A spring 14 interposed between the two is a stopper plate provided on the stop piece 4 that moves downward to a position where the plunger 2 opens by a predetermined value or more with respect to the opening area of the oil passage 1 formed in the main pressure regulating valve body 1. There is a switching valve whose position is changed by A, and when the switching valve 14 compresses the spring 15 and moves downward, the pressure oil P is released.

is connected to the stop piston 10 from the oil passage 17 via the orifice 16.
, and the stop piston 10 rises. This stop piston 10 raises the stop piece 4 via the raising bolt 11, and the switching valve 14 is held at the neutral position at the highest position where the stop piston 10 is raised.
18 and 19 are oil passages 19'' formed in the main pressure regulating valve body 1.
21 is a piston of the servo motor cylinder 20, which communicates the opening of the guide vane with the servo motor cylinder 20 of the guide vane.

In the above configuration, the plunger 2 normally moves up and down in accordance with the control oil pressure Pc from the pinolotl valve (not shown).

That is, pressure oil P is always acting on the upper chamber of the valve servo motor 3, but when the oil pressure Pc in the lower chamber increases, the valve servo motor 3 moves upward due to the difference in area between the upper and lower parts of the valve servo motor 3. do. On the other hand, when Pc becomes lower, the force acting on the upper surface of the valve servo motor 3 overcomes the force acting on the lower surface, so the valve servo motor 3 descends. When the valve servo motor 3 moves up and down, the plunger 2 directly connected to it moves up and down, and the pressure oil Ps acts on the right and left chambers of the servo motor cylinder 20 of the guide vane through the pipe 19 or the pipe 18. In this way, oil pressure PK and PL increase, but
In either case, the other hydraulic pressure (P in the former case, PK in the latter case) is drained from the main pressure distribution valve and decreases, so the pressure difference between the left and right sides of the servo motor piston 21 increases. Thus, the servo motor piston 21 opens and closes, and the speed thereof is approximately proportional to the displacement of the plunger 2. That is, when a fast closing action is required, the plunger 2 needs to move down significantly, and when a slow closing action is required, the plunger 2 must not be allowed to move down significantly. The same applies to the opening operation. Now, when the plunger 2 is displaced downward by more than SL2, the striking plate A integrated with the stop piece 4 pushes down the switching valve 14 and the switching valve 14 switches, so that the hydraulic pressure P for driving the stop piston 10 is increased.

acts on the lower surface of the stop piston 10 and gradually pushes it up from its lower limit position (SI-. in terms of displacement).
Then, when the stop piston 10 rises by SLl-S, the switching valve 14 becomes a neutral state as shown in FIG. The piston 10 stops moving upward and remains stationary at that position. Thus, the allowable downward displacement of the plunger 2 is initially SL4, but gradually decreases and finally reaches SL2. Here SL
l corresponds to the closing speed TanθL1 and SL2 is TanOL
Needless to say, it is equivalent to 2. Then, when the actual guide vane opening approaches the guide vane opening operation command signal, the lower surface pressure PO of the valve servo motor 3 rises, and the plunger 2 begins to return to the neutral state, the switching valve 14 stops again. Since the oil acting on the lower surface of the piston 10 is discharged, the stop piston 10 is lowered by the spring 13, and the closing limit value of the main pressure distribution valve becomes SLl again. Here, the time required for the limit value to shift from SLl to SL2 can be adjusted by the aperture 16. Furthermore, the more the plunger 2 is displaced downward, the more the switching valve 14 is also switched downward, the stop piston 10 is operated quickly, and the limit value quickly changes to SI-. transition to. This is consistent with the water hammer characteristic that the higher the closing speed, the longer the operation cannot be continued, and there is also rationality here. Furthermore, the limits Ll and SL2 can be adjusted by changing the positions of the gaps at the upper ends of the bolts 11 and the switching valve 14, respectively.

〔Effect of the invention〕

According to the present invention, water pressure fluctuations and water turbine rotational speed fluctuations can be reliably suppressed to a small level at any guide vane opening degree.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing servo motor control by the pressure distribution valve of a conventional water turbine speed governor, and FIG. 2 is a diagram showing servo motor control by the pressure distribution valve of the water turbine speed governor of the present invention. 3 and 4 are cross-sectional views for explaining the operation of the pressure distribution valve used in the water turbine governor of the present invention. 1... Main pressure distribution valve body, 2... Plunger, 3...
・Valve servo motor, 4...stop piece, 10
...Stop piston, 14...Switching valve, 16...
・Aperture, 20...Servo motor cylinder, 21...
servo motor piston.

Claims (1)

[Claims] 1 A valve servo motor 3 for operating a plunger 2 is provided in the main pressure regulating valve body 1 integrally with the plunger 2, and the main pressure regulating valve body 1 is configured such that the operating direction of the servo motor 20 for driving the guide vanes to open and close is controlled by the plunger 2. Oil line to be switched 1
The opening areas of the oil passages 18' and 19' are controlled by the position of the plunger 2, and the oil passages 18' and 19' are
In the pressure distribution valve for a water turbine governor, which controls the closing speed of the guide vanes according to the amount of oil flowing through the oil passages 18' and 19', the plunger 2 is operated by the valve servo motor 3 to close the oil passages 18' and 19'.
A switching valve 14 is provided which operates when the oil passages 19' are moved beyond a predetermined opening position SL_2, and the operation of this switching valve 14 moves the plunger 2 to a predetermined opening position SL of the oil passages 18' and 19'.
A pressure distribution valve for a speed governor for a water turbine, characterized in that a stop piston 10 is provided for operating a valve servo motor 3 so as to pull the valve back within _2.