JPH0351939B2 - - Google Patents

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention is used for steam valves, particularly steam systems of steam turbines, and includes a butterfly-type intermediate check valve and a butterfly-type intercept valve. This invention relates to a steam valve housed in two valve body casings.

(Prior Art) Generally, an intermediate check valve and an intercept valve are provided at the low-pressure turbine inlet of a nuclear steam turbine to prevent steam from flowing into the low-pressure turbine during an emergency trip or load interruption of the turbine. ing.

This type of conventional intermediate check valve and intercept valve has an intercept valve 53 and an intermediate check valve 55 built in separate holes in one valve casing 51 forming a steam flow path, as shown in FIG. A combination type that blocks the tract is known.

By the way, this type of combination steam valve is suitable for use in power machines that have a compact valve, high working pressure and temperature conditions, and low steam flow rate, but it has a complicated structure. However, the production cost is high, and nuclear steam turbines with large steam flow rates have the disadvantage that the steam valves are large.

Further, FIGS. 3 and 4 show typical configurations of an intermediate check valve and an intercept valve using a butterfly type valve, and are views viewed from the side and the front, respectively. In both figures, the butterfly type valve generally has the same configuration for both the intermediate check valve 1 and the intercept valve 2, and the valve body side includes valve discs 1a, 2a, valve shafts 1b, 2b, and bearing parts 1c, 2c. , mainly composed of valve bodies (casings) 1d and 2d with flanges at both ends.
The force for rotating the valve discs 1a, 2a is transmitted from oil cylinders 3 and 4, which are drive devices, via valve shafts 1b, 2b, levers 1e, 2e, and drive rods 1f, 2f.

The oil cylinders 3 and 4 generally receive high-pressure oil, and contain oil cylinder pistons 3a, 4a (not shown) that guide the opening direction of the valve, and closing springs 3b, 4b (not shown) that guide the valve closing movement. Spring box 3 for storing (not shown)
It is composed of c and 4c. The spring boxes 3c, 4c and the oil cylinders 3, 4 are connected by fastening bolts 3d, 4d, and the spring boxes 3c, 4c are connected to the valve bodies 1b, 2b, respectively.
Attach 1 tightening bolt to the 1g and 2g brackets.
It is fixed by h and 2h.

(Problem to be solved by the invention) Although the butterfly valve has such a configuration,
The prior art valve shown in FIGS. 3 and 4 has the following improvements.

(1) Considering the overhaul of the intermediate check valve 1 and intercept valve 2, the valve body (casing) 1d,
2d is connected to the upstream pipe 5 and downstream pipe 6 by flanges 5a and 6a, respectively, and gaskets 5b and 6b are used to prevent steam leakage at the flanges, but intermediate check valve 1 and intercept valve 2 are also installed. Based on the idea that the valves are independent from each other, they have connecting flanges 1i and 2i, and a gasket 7b is inserted between them and fixed with a fastening bolt 8.

In general, in nuclear power turbines, the number of gasket seals should be kept to the minimum necessary when considering steam leakage, and from this point of view as well, the connection between intermediate check valves and intercept valves should be made using flanges, gaskets, and fastening bolts. It would have been more desirable to integrate the main body casing.

(2) Spring boxes 3C, 4C and oil cylinder 3, which are drive devices,
4 are generally placed perpendicular to the steam pipes 5, 6, i.e. the steam flow. This is the fifth
This figure incorporates the idea of the positional relationship of the driving device of the conventional combination valve shown in the figure, but the arrangement space V ₁ of the entire valve is V ₁ = L ₁ × L ₂ × L ₃ L ₁ : Intermediate check valve Intercept valve length in the steam flow direction L ₂ : Length from the valve body to the tip of the oil cylinder body L ₃ : From the tip of the drive side bearing to the spring box mounting bracket (both shown in Figures 3 and 4) Therefore, it was desired to improve the reduction of _L2 , _L3, etc. by improving the arrangement of the valve body and oil cylinder.

In particular, reducing the volumetric space of intermediate check valves and intercept valves plays a major role in streamlining equipment layout, and ideally they should be as compact as possible in terms of ease of inspection for operators, securing passages, and workability when disassembling equipment. It is true.

An object of the present invention is to provide a steam valve that satisfies the conditions required for intermediate check valves and intercept valves, is excellent in steam leakage resistance, facilitates maintenance and inspection, and is made as compact as possible as a whole. It is in.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to achieve the above object, the steam valve of the present invention incorporates two butterfly valves arranged side by side along the axial direction inside the valve body casing. , the butterfly valve on the upstream side is used as an intermediate blocking valve, the butterfly valve on the downstream side is used as an intercept valve, and flanges are provided at both ends of the valve body casing to connect with the respective mating pipes, and further, both butterfly valves A driving device including a driving rod that applies an opening/closing force, an oil cylinder piston, an oil cylinder that houses a spring, and a spring box are installed in parallel in the steam flow direction and in opposite directions with the valve body casing in between. It is something to do.

Since the steam valve of the present invention is constructed as described above, the valve storage volume is the smallest compared to any other arrangement. Moreover, since the center of gravity of the steam valve is closer to the center of the valve body than in conventional steam valves, it is not only possible to install a support approximately in the center of the valve body to receive the weight of the valve body and drive device. Even during the transient period of sudden valve closing, there is no unbalanced load from the upstream and downstream piping lines. Furthermore, since the center of gravity is stable during assembly and disassembly of the valve body, assembly and disassembly can be carried out safely and easily.

(Example) Hereinafter, a steam valve of a steam turbine according to the present invention will be described.
This will be explained with reference to the figures and FIG. In FIGS. 1 and 2, components that are the same as those of the prior art are designated by the same reference numerals.

The arrangement of the intermediate check valve 1 and the intercept valve 2 in FIG. 1 with respect to the steam flow is the same as in the prior art, but both of these valves are housed in one valve body (casing) 10. The valve body 10 has flange portions 10a and 10b at both ends and connects with the connecting pipes 5 and 6, and steam sealing is performed by gaskets 5b and 6b and fixing bolts 5a and 6a. Since it does not have a flange part or gasket part to which 2 is connected, the steam leakage point is 1.
It has a reduced number of parts. The reason why both ends of the valve body 10 are made into flanges is to take into account the disassembly and inspection of these valves, and during inspection, they are simultaneously separated by the pipes 5 and 6 and inspected outside the piping system.

Further, the present invention is characterized in that the oil cylinders 3 and 4 and the spring boxes 3c and 4c, which are drive devices, are arranged facing each other and in opposite directions according to the flow of the steam piping. Although the structure of the drive device itself is the same as that of a conventional valve, brackets 10c and 10d are provided on the main body 10 side to fix the drive device side so that it can be installed in the direction of steam flow.

FIG. 2 shows a side view of the steam valve according to the present invention, and when compared with the conventional side view of FIG. 4, it is clear that the steam valve has a large advantage in terms of the volume space it occupies. The arrangement space V ₂ of the present invention is V ₂ = L ₁ × L ₄ × L ₅ ≒ 1/2 × L ₁ × L ₂ × L ₃ = 1/2 V ₁ L ₁ : Same as conventional valve L ₄ : Same as conventional valve Corresponds to L ₂ , but can be reduced to approximately 1/2 the length. L ₅ : Corresponds to L ₃ of a conventional valve, and can be expressed by the equivalent length. A steam valve can be installed in approximately 1/2 the installation space of a conventional valve. Can be installed.

In the present invention, flange portions 10 are provided at both ends of the valve body casing 10, each of which connects to a mating pipe.
a, 10b, and both butterfly valves 1, 2 are provided.
A driving device including a driving rod for applying an opening/closing operation force, an oil cylinder piston, an oil cylinder for housing a spring, and a spring box are installed in parallel in the steam flow direction and in opposite directions with the valve body casing 10 in between. So,
Since the center of gravity of the steam valve is located closer to the center of the valve body than in conventional steam valves, it is not only possible to install a support to receive the weight of the valve body and drive device approximately in the center of the valve body, but also to There is no uneven load from upstream or downstream piping lines even during sudden closing. Furthermore, since the center of gravity is stable during assembly and disassembly of the valve body, assembly and disassembly can be carried out safely and easily.

As described above, the steam valve according to the present invention has the same components and the same driving method as the conventional valve, so it can be easily realized without including any technically unknown parts. This is not related to the rise in product prices. Furthermore, as shown in Figures 1 and 2, it is treated as a steam valve with two valves housed in one valve body, and because it is compact, it can be easily installed with a drive device from factory dispatch to on-site installation. It is possible to transport and bring in the product as it is.

With conventional steam valves, it is possible to transport the valve body and drive device together, but after completing the operational adjustment with the drive device at the factory, it is necessary to separate the valve and readjust it after installation on site. However, according to the steam valve according to the present invention, it is possible to transport the valve in one piece after adjustment at the factory, so there is an advantage that adjustment after installation on site is not necessary.

It goes without saying that the present invention described above can be applied not only to nuclear power plants, but also to steam valves used in plants that frequently use butterfly valves, such as geothermal plants.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, by housing two valves in one valve body casing, the number of flanges connecting the two valves can be reduced, and the number of steam leakage points can be reduced as well. ,
By installing the two valve drive devices in the steam flow direction and in opposite directions with the valve body in between, the entire valve can be made more compact, which not only streamlines equipment layout, but also makes valve manufacturing easier. It would be desirable to be able to transport and adjust the valve body and drive unit as an integrated unit from time to time until on-site installation, thereby improving work efficiency. Furthermore, since the center of gravity of the steam valve is located close to the center of the valve body, it is not only possible to install a support approximately in the center of the valve body to receive the weight of the valve body and drive device, but also to prevent Even at times, it is not subject to unbalanced loads from upstream and downstream piping lines. Furthermore, since the center of gravity is stable during assembly and disassembly of the valve body, assembly and disassembly can be carried out safely and easily.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view of the steam valve of the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a partially cutaway plan view of the steam valve of a conventional steam turbine. FIG. 4 is a side view thereof, and FIG. 5 is a longitudinal sectional view showing a conventional combination steam valve. 1... Intermediate check valve, 1a... Intermediate check valve desk, 2
...Intercept valve, 2a...Intercept valve desk, 1d, 2d...Valve body casing, 1b, 2
b... Valve shaft, 3, 4... Oil cylinder, 5, 6... Piping.

Claims (1)

[Claims] 1. Two butterfly valves are installed inside the valve body casing side by side along the axial direction, the upstream butterfly valve is used as an intermediate blocking valve, the downstream butterfly valve is used as an intercept valve, and both ends of the valve body casing are installed. Each of the butterfly valves is provided with a flange portion that connects to the mating piping, and a driving device including a driving rod that applies opening/closing force to the butterfly valves, an oil cylinder piston, an oil cylinder that stores a spring, and a spring box is attached to the valve body casing. A steam valve characterized in that they are installed in parallel in the steam flow direction and in opposite directions to each other.