Steam turbine
In a steam turbine plant in which a turbine casing containing a turbine is constituted of an upper-half casing and a lower-half casing, nozzles are provided to the upper-half casing and a steam supplied through main steam piping lines are delivered into the upper-half casing. Main steam pipes for supplying a steam from respective main valves to the respective nozzles are each formed so as to be dividable in a position out of the installation area of the upper-half casing.
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1. Field of the Invention
The present invention relates to a steam turbine plant.
2. Description of the Related Art
Conventional steam turbine plants include one disclosed in JP, A 60-159310, for example. JP, A 60-159310 discloses a steam turbine having a dual casing structure composed of an inner and an outer casing wherein the space between the inner and outer casings is divided by a partition wall into a first steam passage allowing part of main steam to pass along the outer surface of the inner casing and a second steam passage allowing cooling steam to pass along the inner surface of the outer casing, and wherein an opening/closing device is provided to each of the first and second steam passages, whereby thermal stress in the inner and outer casings is reduced even if this steam turbine is frequently started and stopped. JP, A 60-159310 further discloses a structure wherein main steam piping line for supplying a steam from a boiler is connected to an upper portion of the outer casing, and wherein an exhaust hole is provided for discharging exhaust steam that has worked at various stages of the turbine and sending it to a next turbine.
SUMMARY OF THE INVENTIONGenerally, in order to facilitate the removal of the upper-half casing when performing maintenance of a steam turbine, the main steam piping line for supplying a main steam from steam generating equipment such as boiler equipment to the steam turbine is configured to be connected to a lower-half casing. As a result, the steam turbine requires a space below it for installing pipes of the main steam piping line having a large bore size. This increases the installation height of the turbine, resulting in a high-rise of the turbine building.
On the other hand, as in the above-described JP, A 60-159310, in the case where main steam piping line connected to the turbine casing is configured to be connected to an upper portion of the turbine casing, when attempting to disconnecting and conveying the turbine casing upon maintenance, the main steam piping line connected to the upper portion of the turbine casing unfavorably interferes with the disconnecting and conveying of the turbine casing, thereby making the maintenance operation troublesome.
It is an object of the present invention to provide a steam turbine plant which allows the setting level of the steam turbine to be lowered and enables the maintenance of the steam turbine to be facilitated.
To achieve the above-mentioned object, the present invention provides a steam turbine plant in which a turbine casing containing a turbine is constituted of an upper-half casing and a lower-half casing, the steam turbine plant comprising a main steam piping line, and a nozzle provided to the upper-half casing and through which a steam supplied through the main steam piping line is delivered into the upper-half casing, wherein the main steam piping line includes a main steam pipe for supplying a steam from a main valve to the nozzle and the main steam pipe is formed so as to be dividable in a position out of an installation area of the upper-half casing.
According to the present invention, a steam turbine plant can be provided that allows the setting level of the steam turbine to be lowered and enables the maintenance of the steam turbine to be facilitated.
BRIEF DESCRIPTION OF THE DRAWINGS
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
First Embodiment
Meanwhile, the main steam piping lines 10 generate thermal expansion and contraction due to the temperature difference between a plant operation time and a plant stop time, thereby generating reaction force moments with respect to the boiler equipment. 500 and the steam turbine 100 which are fixedly mounted. As shown in
On the other hand, in this embodiment, the main steam piping lines for supplying a steam to the steam turbine 100 is connected to the upper-half casing 101, and further the short pipes 12 can be removed during maintenance. Therefore, even when the disconnection of the upper-half casing 101,. turbine rotor 103, turbine blade 104 and the like during maintenance reduces the weight over the lower-half casing 102, the lower-half casing 102 is not subject to thermal expansion and the like of the main steam piping lines, thereby eliminating the occurrence of movement of the lower-half casing 102. In other words, as shown in
In the conventional art, in which the main steam piping lines 10 are each connected to the lower-half casing 102 as shown in
When the upper-half casing 101 of the steam turbine 100 is to be conveyed after having been disassembled, the upper-half casing 101 is first moved in a vertically upward direction, and then conveyed in the other direction from the position where no interfering object has come to be found therearound. Therefore, when the upper-half casing 101 is to be conveyed in the vertically upward direction, it is desirable that the main steam pipes 11 and the main valves 90 disconnected from the upper-half casing 101 do not interfere therewith. For this purpose, as shown in
Furthermore, in this embodiment, there are provided the main steam pipe nozzle portion flanges 106. When the main steam pipe flanges 14 are each disposed far apart from the nozzle 105, the short pipes 12 have to become correspondingly longer, thereby unfavorably increasing their weights. Therefore, when the upper-half casing 101 is conveyed with the short pipes 12 connected therewith, the weights to be conveyed become heavier, resulting in inconvenience for conveyance operation. In addition, there occurs the need for a wide range of space for placing the upper-half casing 101 after conveyance. In contrast, in this embodiment, when the upper-half casing 101 is disconnected and conveyed, the short pipes 12 are removed from the main steam pipe nozzle portion flanges 106, thereby facilitating the conveyance of the upper-half casing 101. The length of the short pipe 12 should be designed to be a length such that the main valve 90 takes a position that does not interfere with the upper-half casing 101 when the upper-half casing 101 is disconnected and conveyed.
The steam turbine 100 with the above-described structure may also be applied to a conventional high-floor power generation plant. Moreover, this steam turbine 100 can be applied to a low-floor power generation plant that has been difficult to realize when the main steam piping lines 10 are connected to the lower-half casing 102 as in the conventional steam turbine 100.
In this way, the high-pressure and middle-pressure or reheat main steam piping lines 10 that have conventionally been connected to the lower-half casing 102, are connected to the upper-half casing 101 as shown in
Also, when the main steam pipes 10A are each connected to the casings of the steam turbine 100 by sandwiching them between the upper-half casing 101 and the lower-half casings 102 of the steam turbine 100 as described above, an end portion of each of the main steam pipes 10A is formed with a flange structure 13 as shown in
Here, each of the main steam pipes 10A is installed to extend in a route such that it is bent in the direction perpendicular to the central axis of the steam turbine 100 and the central axis of each of the main steam pipes 10A exiting the steam turbine 100, and thereafter again each of them is bent in the axial direction of the steam turbine 100, whereby a reaction force due to thermal expansion and contraction of the main steam piping lines 10 upon operation and stoppage of the steam turbine 100 is not applied thereto. This allows, as shown in
By singly adopting one of the structures described above, or combining some of these structures, it is possible to lower the installation height of the steam turbine. This allows a turbine building to be designed to be low, or enables an outdoor installation method without a turbine building to be applied. In particular, when a steam turbine with a low height is installed outdoors without a turbine building, a small-sized crane requiring no access to a high position can be used as a crane for hoisting the upper-half casing, turbine rotor, and the like upon maintenance of the steam turbine. This makes a required maintenance space smaller, and also allows safe and economical maintenance to be implemented. Moreover, this eliminates the need to support reaction forces due to heat transfer by the lower-half casing of the steam turbine and a foundation of the steam turbine when the steam turbine casing is removed, thereby reducing the possibility of accidents. Furthermore, the capability of making the turbine foundation low enables an economical power generation plant that reduces the cost of civil engineering to be constructed.
Claims
1-6. (canceled)
7. A steam turbine plant comprising:
- a boiler equipment for generating a drive steam;
- a steam turbine driven by said steam from said boiler equipment;
- a power generator driven by said steam turbine;
- a main steam piping line connecting said boiler equipment and said steam turbine;
- a main valve provided in way of said main steam piping line; and
- a condenser for condensing a team discharged from said steam turbine; and wherein said steam turbine includes a turbine, a turbine casing containing said turbine, and a nozzle provided to said turbine casing and to which said main steam piping line is connected;
- said turbine casing includes an upper-half casing and a lower-half casing, and said nozzle is provided to said upper-half casing; and
- said main valve is set at a level higher than the setting level of said steam turbine.
8. The steam turbine plant according to claim 7, wherein a portion of said main steam piping line connecting said main valve and said nozzle is formed so as to be dividable in a position out of an installation area of the upper-half casing.
Type: Application
Filed: May 9, 2006
Publication Date: Sep 14, 2006
Applicant:
Inventors: Masaki Takahashi (Hitachi), Yoshifumi Kubo (Takahagi), Akitaka Tateishi (Hitachinaka), Katsutoshi Higuma (Takahagi), Akio Umino (Hitachi), Yasuhiro Oda (Utsunomiya)
Application Number: 11/430,010
International Classification: F01K 13/00 (20060101);