JPH0110445Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an inlet valve of a water turbine, particularly the structure of the casing and the inlet valve.

[Technical background of the invention]

The casing inlet of a typical water turbine has a structure as shown in FIG.

That is, the inlet valve 2 is installed on the upstream side of the casing 1 of the water turbine.
is provided so that water flows into the inlet valve 2 from the iron pipe 3 on the upstream side. The inlet valve 2 consists of a rotatable valve body 4 and a valve body 5 that accommodates the valve body 4. A part of the valve body 5 has a movable seat 6 that moves back and forth to adjust the opening degree of the valve body 4. It is slidably installed.

Specifically, a recess is formed in the valve body 5, the protrusion of the movable seat 6 faces the recess, the recess is divided into two pressure chambers 7 and 8, and a water supply port is provided in each pressure chamber 7 and 8. Pressure water is supplied through 7a and 8a.

When the supply to the water turbine is to be stopped, pressurized water is injected into the pressure chamber 7 through the water supply port 7a, and the movable sheet 6 is moved upstream (to the left in the figure). The seat surface is brought into close contact with the seat surface of the valve body 4 to block the inflow of water. When water is supplied to the water turbine, the pressure chamber 8 is supplied through the water supply port 8a.
Pressurized water is injected into the movable seat 6 to move the movable seat 6 downstream (to the right in the figure) and rotate the valve body 4.

[Problems with background technology]

In the case of the conventional water turbine inlet structure as described above, when the movable seat 6 is closed, the pressure inside the pressure chamber 7 may be damaged due to damage to the seal 9, or the pressure water supplied into the pressure chamber 7 may If the pressure is lower than a predetermined value, the seat surface of the movable seat 6 will not come into close contact with the seat surface of the valve body 4, but when the pressure inside the casing 1 becomes approximately equal to the water pressure on the upstream side, it will balance with the movable seat 6. Therefore, even if the pressure inside the pressure chamber 7 is low, the valve body 4
closely adhere to. At this time, the water pressure inside the casing 1 decreases, so the movable sheet 6 is pushed back again. When such an operation is repeated and so-called self-excited vibration occurs, the water pressure inside the iron pipes 3 increases, and eventually the iron pipes 3 may become out of alignment.

[Purpose of invention]

The present invention was made to improve the above-mentioned conventional problems, and its purpose is to prevent the pressure inside the iron pipe from increasing due to self-excited vibration, and thereby improve the quality of the iron pipe. An object of the present invention is to provide a structure of an inlet valve for a water turbine that does not cause problems such as bursting.

[Summary of the idea]

In order to achieve this purpose, the present invention connects the casing of the water turbine and the valve body of the inlet valve or the iron pipe with a bypass pipe, and electrically connects the valve installed in the bypass pipe with a pressure detection device that measures the water pressure inside the iron pipe. The outline of the system is that when the water pressure inside the iron pipe reaches a predetermined value or higher, the valve provided in the bypass pipe is opened, allowing the water inside the iron pipe to escape into the casing.

[Example of idea]

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a cross-sectional view showing the structure of the casing inlet of the water turbine according to the present invention. On the upstream side of the casing 1, an inlet valve 2 with a valve body 4 housed in a valve body 5 similar to the conventional example is provided. Water supply iron pipe 3 is connected to this inlet valve 2.
is connected to allow water from the iron pipe 3 to flow into the casing 1 via the inlet valve 2. Further, the protrusion of the movable seat 6 is made to face the recess formed in the valve body 5, and the recess is divided into two pressure chambers 7 and 8.
By supplying pressurized water to the pressure chamber 7 through the water supply port 7a, the movable seat 6 is moved to the left in the figure, the seat surface of the movable seat 6 is brought into contact with the seat surface of the valve body 4, and the valve body 4 is moved to the left side in the figure. By preventing water from rotating, and supplying pressurized water to the pressure chamber 8 through the water supply port 8a, the movable seat 6 is moved to the right in the figure, and the valve body 4 and the movable seat 6 are The valve element 4 is rotated by releasing the contact state with the iron pipe 3 to allow water from the iron pipe 3 to flow into the casing 1.

Further, the valve body 5 and the casing 1 are connected by a bypass pipe 10, and a side valve 11 is interposed in the middle of the bypass pipe 10. On the other hand, the iron pipe 3 is provided with a pressure detection device 12 for detecting the water pressure inside the iron pipe 3, and the operation of the side valve 11 is controlled by sequence control so that the pressure detection device 12 and the side valve 11 are interlocked.

The operation of the side valve 11 described above will be explained based on FIG. If the pressure detected by the device 12 exceeds a predetermined value that exceeds the hydrostatic pressure, for example, if the pressure is such that there is a risk of the iron pipe bursting, the side valve 1 is activated.
1 is opened to allow water in the iron pipe 3 to escape into the casing 1. When the pressure inside the iron pipe 3 falls below a predetermined value, the side valve 11 is closed again to prevent water inside the iron pipe from unnecessarily escaping into the casing.

In the illustrated example, the casing 1 and the valve body 5 are connected by the bypass pipe 10, but the casing 1 and the iron pipe 3 may be connected.

[Effect of idea]

As explained above, according to the present invention, the casing of the water turbine and the inlet valve or the iron pipe for water supply are connected by a bypass pipe, a valve is provided in the middle of the bypass pipe, and the iron pipe is connected to the water pressure inside the iron pipe. This pressure detection device and the valve are electrically connected, and when the inlet valve is fully closed, the water pressure inside the iron pipe pulsates, and the detected pressure exceeds a predetermined value exceeding the hydrostatic pressure. When this happens, the above valve is opened to allow the water inside the iron pipe to escape into the casing.
The self-excited vibration of the inlet valve can prevent the pressure inside the iron pipe from increasing to a dangerous pressure, and the worst situation such as the iron pipe bursting can be avoided, which is advantageous in terms of safety. Since the valve of the bypass pipe is in a closed state, water does not escape unnecessarily, and the structure of the present invention does not require major changes to the conventional structure, and existing valves, etc. can be used as they are. It has many effects.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the structure of a conventional water turbine inlet valve.
FIG. 2 is a sectional view of the structure of the inlet valve according to the present invention, and FIG. 3 is a block diagram illustrating the operation of the valve provided in the bypass pipe. 1... Water turbine casing, 2... Inlet valve, 3...
... Iron pipe, 4 ... Valve body, 5 ... Valve body, 6 ... Movable seat, 10 ... Bypass pipe, 11 ... Side valve, 12
...Pressure detection device.

Claims (1)

[Scope of utility model registration request] The casing of the water turbine and the valve body of the inlet valve upstream of the casing or the iron pipe that also supplies water to the inlet valve are connected by a bypass pipe, and a valve is provided in the middle of this bypass pipe. The iron pipe is equipped with a pressure detection device that detects the water pressure inside the iron pipe, and this pressure detection device and the valve are electrically connected, and when the inlet valve is fully closed, the water pressure inside the iron pipe causes pulsations, and the detected pressure increases. An inlet valve for a water turbine, characterized in that the valve is opened when the hydrostatic pressure exceeds a predetermined value.