Steam turbine

Abstract

The present invention provides a steam turbine that supplies cooling steam at more uniform pressure to a blowing hole of the inner ring of a diaphragm to further increase thermal efficiency. An outer ring for forming a diaphragm of the steam turbine comprises a first outer ring. The first outer ring has an annular outer ring cavity to which external cooling steam is supplied. A radial direction cooling hole connecting with the outer ring cavity is formed in the stator blades connected to the first outer ring. An annular inner ring cavity connecting with the radial direction cooling hole is formed in a first inner ring constituting one diaphragm together with the first outer ring. Cooling steam blowing holes connecting an annular wheel space and the inner ring cavity are formed. The annular wheel space is formed between the first inner ring and a rotor wheel adjacent to the first inner ring.

Description

technical field [0001] The present invention relates to a steam turbine provided with a mechanism for cooling a rotor by supplying cooling steam from the outside. Background technique [0002] Ferritic heat-resistant steel, which is good in manufacturability and economy, has been used in most high-temperature parts of thermal power generation equipment. In steam turbine power generation equipment, since the steam temperature is generally below 600°C, ferritic heat-resistant steel is also used in major parts such as rotors and blades of steam turbines. However, in recent years, with the background of environmental protection, the efficiency of thermal power generation equipment has been actively developed, and steam turbines using high-temperature steam at about 600°C are in operation. Some of these steam turbines are made of ferritic heat-resistant steel. Parts whose various characteristics cannot meet the required characteristics. [0003] Therefore, there are also exampl...

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Problems solved by technology

[0009] However, in the above patent document 1 figure 1 In the case of the case, it is not clear whether the steam piping that penetrates the shell penetrates into the partition or forms a cooling passage different from the partition

It is difficult to directly connect the steam pipe to the blowout hole and supply cooling steam to the blowout hole at a uniform pressure

exist image 3 In the example, no steam piping is provided for each stationary blade, and there is a circumferential direction flow path of cooling steam, and the cooling steam from the blowing hole is intended to flow uniformly into the root of the moving blade, but the pressure of the cooling steam cannot be ensured to be sufficient for each blowing hole. Uniformity of

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