JPS5965577A - Protective device for hydraulic machinery - Google Patents

Abstract

PURPOSE:To improve safety in failures by continuously giving closing commands and slow speed commands to a servo motor through the operation of a command change-over unit for back-up when a governor means is not interlocked with the servo motor for driving a flow regulating means. CONSTITUTION:A distributing valve 4 is controlled through a link 2 and a pilot valve rod 3 by a speeder 1 for giving opening and closing commands to controllably supply pressurized oil from a pressurized oil source to a servo motor 5. In a control unit for controlling a flow regulating means such as a movable guide valve through a rod 5 by power of the servo motor 5, a servo motor opening setting cam 15 is mounted on a return shaft 12 interlocked with the rod 6 and rotated through a return wire 7. And a change-over valve 16 is controlled by said cam 15 to operate a closing speed limiting cylinder 17. Also, a change-over valve 19 provided parallel to the change-over valve 16 is changed over by the descending movement of a weight 11 when a wire 7 is cut, so that the descending speed of said valve rod 3 can be limited through the cylinder 17.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a protection device for a hydraulic machine that improves safety by preventing an abnormal pressure rise in a waterway when the hydraulic machine is closed in an emergency. The present invention relates to a protection device for hydraulic machinery suitable as a protection device for 7 Lances type, mixed flow and propeller type hydraulic reaction turbines, pump turbines of the same type and other Pelton type impulse turbines.

[Prior art]

Generally, a group of movable guide vanes or needles or other flow regulating means are arranged around the runner of a hydraulic machine, and the flow regulating means controls the water flow to the turbine during power generation or the like. Such flow regulating means is usually driven by a servo motor.

By the way, for example, in a pump water turbine, there are cases where the load suddenly decreases during operation of the water turbine, or there is a need to stop the operation of the water turbine urgently due to equipment failure or the like. In this case, as a characteristic of pump turbines, while the flow rate increases rapidly due to load shedding, etc., the flow rate suddenly decreases at a certain point due to the centrifugal force of the runner, and the internal pressure of the waterway such as iron pipes increases rapidly. There is a risk. From this, in pump water turbines, etc.,
Sudden closing of the flow rate adjustment means when the load is abruptly interrupted is
Furthermore, if the pressure inside the waterway is increased, there is a risk of serious accidents such as damage to the waterway. Therefore, during an emergency stop of such a hydraulic machine, it is necessary to control the closing speed of the flow rate adjusting means to a predetermined slow speed. In addition,
It is desirable to close the flow rate adjustment means at a high speed until the flow rate suddenly decreases during the flow rate increase stage during load shedding, which is the so-called turning point. However, recently, in response to the trend of high head (hydraulic machinery), the servo motor for driving the flow rate adjustment means is set at least two or more slow speeds, and an emergency closing command is given by the control device. The speed governor is interlocked with the servo motor, and the amount of movement is fed back to the control device to correct it to a predetermined emergency closing speed, giving the servo Tanabata the optimum slow speed. There is. For example, as shown by the solid line ■ in Fig. 1, the servo motor is closed at the maximum speed at the initial stage, and after a predetermined servo motor opening (Sol), the closing speed is reduced to a gentle closing speed to control the water pressure of the iron pipe. This is to suppress water pressure in the waterway (not shown), rate of increase in rotational speed, etc. to optimal values within specified values.

However, in conventional hydraulic machines, there has been a problem with the speed regulating means that works in conjunction with the servo motor and feeds back the amount of movement of the servo motor to the servo motor control device to correct the emergency closing speed of the servo motor.

In other words, in the conventional inspection speed regulating means, if the interlocking relationship with the servo motor breaks down, the closing speed of the servo motor will not reach the maximum speed regardless of the position of the piston rod. However, the water pressure of the iron pipes could become extremely high, which could lead to the risk of the iron pipes breaking.

The cause of this will be explained with reference to the conventional control system shown in FIG. 1 is a speeder that gives a close command and an open command, 2 is an iJ link connected to this speeder 1, and 3 is a pilot valve rod connected to link 2. A distribution valve 4 is connected to the pilot valve rod 3 and is configured to supply pressure oil from a pressure oil source to the servo motor 5. The operating speed of the piston rod 6 of the servo motor 5 is regulated by the amount of pressure oil supplied according to the closed position of the piston 4A of the distribution valve 4 to the opening. A flow rate adjusting means such as a movable guide valve or a needle (not shown) is connected to the tip of the piston rod 6. Further, 7 is a return wire connected to a pitton rod 6 of the servo motor 5 via a slide 8, which is connected to a return sheep 9 of the speed governor.

A weight 11 is attached to the opposite Kuhn wire side of the return sheep 9 via a wire rope 10, so that the return shaft 12 can be rotated to follow the piston rod 6 with high precision. Letter IPII] 12 has a restoration cam 13
is provided, and a restoring rod 1 that engages with this restoring cam 13
4 was connected to Link 2, and 6 people were able to correct the commands from Subida 1. Zumashi, link 2 is restoration rod 1
The speeder 1 performs a shishi-saw operation based on a command from the speeder 1 using the connecting part with the speeder 1 as a fulcrum, and the command value is corrected by adjusting the height of the fulcrum by engagement with the restoring cam 13 and the restoring rod 14. That's what I do. On the other hand, a servo motor opening degree setting cam 15 is attached to the return shaft 12 to drive a switching valve 16. This switching valve 16 is capable of supplying pressure oil from a pressure oil source to a closing speed limiting cylinder 17, and the piston rod of this closing speed limiting cylinder 17 has a closing speed limiting cylinder 17 of <-18
The lowering speed of the pilot valve rod 3 is moderated through the lower end. In other words, the switching valve 16 normally operates in the oil path 16A.
is in the state of shutting off υ, and with the piston rod 6 of the servo motor 5 moved from the fully open side to the closed side by a certain value, the oil passage 16A is communicated as shown in the figure, and the F lowering speed of the pilot valve rod 3 is changed. The closing speed limit lever 18 acts to relax the closing speed limit lever 18. Note that 19 is a closing speed upper limit lever υ, for example, a nut screwed onto a screw shaft in the form of a rotating piece, and is used to set the upper and lower movement limits of the pilot valve rod 3. This limits the closing position of the distribution valve 4 to the opening of the piston 4A, and prevents sudden operation of the flow regulating means due to excessively rapid flow of pressure oil from the pressure oil source into the servo motor 5. It is designed to prevent

However, in such a conventional regulator structure, if the interlocking relationship between the speed regulating means and the servo motor is broken due to breakage of the return wire 7, etc., the return shaft 12 is moved in the opening direction by the weight 11. When rotating and rapidly closing,
Regardless of the position of the piston rod 6, the servo motor closing speed maintains the maximum closing speed set on the closing speed increase stopper 19 based on the detected movement of the return shaft 12 in the opening direction, for example, as shown by the broken line in FIG. Although the servo motor opening degree and rotation speed shown in ■ will be lower than normal, the water pressure of the iron pipe will become extremely large, exceeding the design water pressure of the iron pipe, and in some cases may cause serious accidents such as destruction of the iron pipe. There was a possibility of a connection. It should be noted that since a cushion mechanism is provided to mechanically prevent shock when the servo motor is about to fully close, the illustration shows the final closing tendency of the servo motor due to this cushion.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and is a simple and easy-to-use system that can give a closing command and a slow speed command to the servo motor even if the interlocking relationship between the speed regulating means and the servo motor breaks down. The purpose of the present invention is to provide a Hoto device for hydraulic machinery that is also highly reliable.

[Summary of the invention]

The present invention provides a backup system that automatically operates in conjunction with the speed governor when the interlocking relationship between the speed governor and the servo motor breaks down, and gives a close command and slow speed command to the servo motor control device. It is equipped with a command switching device.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIG.

It should be noted that this embodiment relates to an improvement of the wire-type control device shown in FIG. 2, and the same components as those in FIG. 2 are designated by the same reference numerals and their explanations will be omitted.

As a command switching device for the back amplifier, a second switching valve 19 is provided in parallel with the first switching valve 16 in an oil passage 16A that passes oil to the opening limit cylinder 17. When the return wire 7 is cut, when the weight @ll descends, it engages with the descending weight 11 and this second switching valve 19 switches to the first
Regardless of the position of the switching valve 16, the oil passage 16a is configured to communicate between the pressure oil source and the opening limit cylinder 17.

With such a configuration, if the return wire 7 is cut, the weight 11 operates the second switching 'f19, and by supplying oil to the opening limit cylinder 17, the closing speed limit lever 18 is activated. The lowering of the pilot valve rod 3, that is, the operating speed of the servo motor 5 in the closing direction can be slowed down through the
It is possible to set the slow closing adjustment speed as shown by the single-dot chain y■ in the figure.

Therefore, if the present invention is applied to a pump-turbine, when an accident such as a load cutoff occurs when using a single water pouch, the closing operation can be changed to the set value at a slow speed during the slow closing operation of the servo motor 5. Even when the return wire 7, which serves as a control means for adapting to the Even if it is shut off, the second switching valve 19 is connected to the oil passage 16A via the weight 11.
By communicating these, it is possible to continue to give a slow speed closing operation signal to the pilot valve rod 3 via the closing speed limiting cylinder 17 and the closing speed limiting lever 18, so that, for example, load shedding when a pump water turbine is in use can be performed. In response to the pressure increase in the iron pipe due to the bending, which causes a temporary decrease in the flow rate, closing the flow rate adjustment means can prevent the pressure increase from being aggravated, and can prevent accidents such as iron pipe breakage. And definitely aim for it. . When using a bong, power cutoff corresponds to load cutoff, but in this case, it is desirable to close the guide vane as quickly as possible in order to prevent bearing damage due to reverse rotation of the runner. No need to apply.

In addition, although the above-mentioned embodiment explained the measures to be taken when the return wire 7 is broken, the present invention can also be applied to perform the slow speed closing operation in the same way when the wire rope 10 on the weight 11 side is broken. can.

Further, in the above embodiment, the present invention is applied to means for mechanically detecting the operation of the piston rod 6 of the servo motor 5, but the present invention is not limited to such a device. It can also be applied to a speed governor that uses a restoration signal, etc., when detecting that the consistency relationship between the electrical restoration signal and the actual transfer @ quantity is broken and using it as an electrical closing speed setting means. Further, although the above embodiment describes a device using a wire, the present invention can also be applied to a device using a connecting means other than a wire, such as a lever device.

〔Effect of the invention〕

As described above, the present invention detects the operation of a servo valve by providing a second switching valve configured to be automatically switched at a predetermined opening depending on a flow metering means such as a kite vane. In the event that the mechanism fails for some reason and the interlocking relationship is disrupted, we have added a means to ensure that the switching valve performs a gentle closure, so it is particularly effective during load shedding when operating a water turbine such as a pump water turbine. etc., safety can be ensured and the intended purpose can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram of a hydraulic machine depending on the opening degree of a servo motor, FIG. 2 is a schematic diagram showing a conventional device, and FIG. 3 is a schematic diagram showing an embodiment of the present invention. 1... Speeder control device, 2... Link control device,
3... Pilot valve rod control device, 4... Distribution valve control device, 5... Servo motor, 7... Return wire speed regulating means, 11... Weight speed regulating means, 12... Letter/shaft adjusting means, 13... Restoration cam speed regulating means, 19...
・Second switching valve (finger cutting device).

Claims (1)

[Claims] 1. A control device that sets a slow speed of at least two stages or more to a servo motor that drives the flow rate adjustment means and issues an emergency closing command; A speed regulating means for correcting the emergency closing speed of the servo motor, which automatically operates by moving with the speed regulating means when the interlocking relationship between the speed regulating means and the servo motor breaks down; A protection device for hydraulic machinery, characterized in that a backup command switching device is provided for giving a closing command and slow speed sliding to a control device of a servo motor.