JPH10196312A - Cooling structure of steam turbine casing flange - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably cool a horizontal flange part regardless of an inside surface shape of a steam turbine by arranging a cooling medium passage between a vertical outside end surface of respective horizontal flanges of a casing upper half part and a casing lower half part and heat reserving materials covered along this outside end surface. SOLUTION: A casing upper half part 1A and a casing lower half part 1B of a steam turbine casing are fastened by a horizontal flange bolt 3 in a part of a horizontal flange 2, and the whole surface is covered with heat reserving materials 4 and 6 including the horizontal flange 2. A cooling medium passage 7 is arranged between an outside end surface 5 of this horizontal flange 2 and the heat reserving material 6, but this cooling medium passage 7 is formed as passages 4A and 4B to communicate with the atmosphere by notching a part of the heat reserving material 4 in its upper part and a lower part, and is arranged so as to use the atmosphere as a cooling medium. According to such a cooling structure, an optional position requiring to cool the horizontal flange 2 in the steam turbine casing can be selected and cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine having a structure for cooling a horizontal flange of a steam turbine casing.

[0002]

2. Description of the Related Art A horizontal flange bolt for fastening the upper and lower horizontal flanges of a steam turbine casing is heated by an effect of high-temperature steam during operation. May become loose due to high temperature creep and cause steam leakage from the horizontal flange surface.

[0003] For this reason, inside the horizontal flange bolts for fastening the horizontal flange portions of the upper half of the vehicle compartment and the lower half of the vehicle compartment,
A cooling steam flow path is formed along a plane substantially parallel to the vehicle interior surface to perform cooling.

FIGS. 3 to 5 show two examples of a conventional cooling structure. FIG. 3 shows a structure in which grooves are formed in the inner surfaces of the horizontal flanges 52A and 52B of the upper half 51A and the lower half 51B of the vehicle compartment, and lids 53A and 53B are welded to the grooves so that the studs 54 are smaller than the studs 54. The cooling steam passages 55A and 55B are formed on the inner side along a plane substantially parallel to the vehicle interior surface.

The steam extracted from the low temperature section of the steam turbine flows through the cooling steam passages 55A and 55B to cool the sections. However, no cooling steam is supplied to the bolt holes 56. The pair of cooling steam channels 55A, 55A
B is provided in a vertically symmetric and left-right symmetric position to prevent generation of thermal stress.

FIGS. 4 and 5 show horizontal flanges 52A and 52B of an upper half 51A and a lower half 51B of a passenger compartment.
The inside of the bolt hole 56 of the bolt 54 for fastening the high temperature pipe 57 is formed along the plane substantially parallel to the inside of the vehicle cabin when the cabin is manufactured, so that the cooling steam flow path 55A,
55B is formed. FIG. 5 shows V-
It is V sectional drawing.

[0007]

In the prior art as described above, the inner surface of the steam turbine casing does not always form a flat portion uniformly over the entire inner surface. In some cases, the horizontal flange of the vehicle compartment cannot be cooled.

Further, since steam extracted from the low-temperature portion is used as the cooling steam, turbine performance is reduced accordingly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art, so that the horizontal flange portion can be reliably cooled irrespective of the inner shape of the steam turbine, and the performance of the turbine is not reduced. It is an object to provide

[0010]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is directed to a vertical outer end surface and a lower outer end surface of a horizontal flange of each of an upper half and a lower half of a passenger compartment. To provide a cooling structure for a steam turbine casing flange provided with a cooling medium flow path between the heat insulating material coated with the heat insulating material, and the space between the vertical outer end face of the horizontal flange and the heat insulating material coated along the horizontal flange, that is, horizontal. Since the cooling medium flow path is formed outside the flange instead of inside, it is completely independent of the shape of the cabin and is not governed by it. It was made to be able to get.

Further, the present invention provides a cooling structure of a steam turbine casing flange in which a miscellaneous air pipe is connected to a cooling medium introduction portion of the cooling medium flow path, and uses miscellaneous air normally provided in a plant as a cooling medium. The piping for the miscellaneous air is communicated with the cooling medium introduction portion of the cooling medium flow path to perform desired cooling by the miscellaneous air, and the efficiency of the turbine is not reduced since low-pressure steam is not used.

Further, according to the present invention, a part of the heat insulating material is removed at an upper part and a lower part of the cooling medium flow path, and the cooling of the steam turbine casing flange is performed by connecting the upper part and the lower part of the cooling medium flow path to the atmosphere. By providing a structure, the cooling medium flow path communicates with the atmosphere at the upper and lower portions thereof, whereby the air flows into the cooling medium flow path from the lower portion as cooling air, and the temperature of the cooling medium flow path rises due to the heat of the passenger compartment. (By the way, in a typical steam turbine, the inner surface steam temperature is 538 ° C. at the highest temperature, and about 20 to 40 ° C. lower in the vicinity of the cooling medium flow path). A natural flow to the upper half of the room is generated, and cooling is promoted. In this case, too, since the cooling steam of the turbine low-pressure section is not used as the cooling medium, the performance of the steam turbine is not slightly impaired.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory view of a cooling structure of a steam turbine casing flange, and FIG. 2 is an image diagram in which the cooling structure is installed.

The upper half 1A of the passenger compartment and the lower half 1B of the passenger compartment are fastened by horizontal flange bolts 3 at the position of the horizontal flange 2, and the entire surface including the horizontal flange 2 has a heat insulating material 4 and a heat insulating material 6. Coated with

A cooling medium passage 7 is provided between a vertical outer end face 5 of the horizontal flange 2 and a heat insulating material 6 coated along the end face.

Note that the cooling medium flow path 7 is
Is not provided on the entire surface, but is selected and provided only for a portion requiring cooling.

The cooling medium flow path 7 is formed by cutting out a part of the heat insulating material 4 at the upper and lower portions thereof, thereby forming a passage 4 communicating with the atmosphere.
A and 4B are formed, and the atmosphere is used as a cooling medium.

Although illustration is omitted again,
A miscellaneous air pipe may be connected to the lower passage 4B, and cooling may be performed by using miscellaneous air or the like provided in the plant as a cooling medium and forcibly supplying it to the cooling medium flow path.

Further, since these cooling medium flow paths 7 are formed on the vertical outer end face 5 of the horizontal flange 2, their positions can be arbitrarily selected. As shown in FIG. 2 is provided aiming at a portion requiring cooling, and as shown by a black arrow in the drawing, for example, a cooling medium, for example, cooling air is discharged to cool the horizontal flange bolt 3.

In the present embodiment, as described above, it is possible to select an arbitrary position in the steam turbine casing where cooling of the horizontal flange 2 is required and perform cooling.

Also, when forced cooling is performed by connecting miscellaneous air pipes, or when air is allowed to flow naturally by opening part of the heat insulating material at the upper and lower portions of the horizontal flange 2, air at ambient temperature is used as a cooling medium. The cooling effect is great because the structure is simple.

Incidentally, the temperature of the horizontal flange bolt 3 at the position of the horizontal flange is approximately 20 times the normal internal steam temperature of 538 ° C., which is the highest temperature of this type of steam turbine (for business and industrial use) during normal operation. The temperature becomes lower by ４０40 ° C.

Therefore, the air of the cooling medium introduced from the lower half of the passenger compartment rises by receiving such heat of the passenger compartment, the specific weight decreases, and a natural flow to the upper half of the passenger compartment occurs. Thus, a cooling air flow path is formed here.

In addition, since the steam in the low-pressure section is not used as the cooling medium as in the above-described conventional apparatus, the output of the steam turbine is not impaired even slightly.

Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to such an embodiment.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

[0026]

As described above, according to the present invention, cooling can be easily performed by selecting a horizontal flange portion requiring cooling irrespective of the inner surface shape of the steam turbine. A highly reliable steam turbine was obtained without loosening due to high-temperature creep and without causing steam leakage from the horizontal flange surface.

According to the second aspect of the present invention, the use of the miscellaneous air as the cooling medium does not waste the steam of the steam turbine as the cooling medium, so that the turbine efficiency does not decrease. It is like that.

Furthermore, according to the third aspect of the present invention, it is possible to use the cheapest atmosphere as a cooling medium by skillfully utilizing the laws of nature with an extremely simple structure, thereby increasing the manufacturing cost and running cost. It could be reduced to width.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cooling structure for a casing flange according to an embodiment of the present invention.

FIG. 2 is an explanatory view conceptually showing an installation position of a casing flange cooling structure according to the embodiment of FIG. 1;

FIG. 3 is a schematic view showing an example of a conventional cooling structure for a casing flange.

FIG. 4 is a schematic view showing another example of a conventional cooling structure for a casing flange.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1A Upper half of cabin 1B Lower half of cabin 2 Horizontal flange 3 Horizontal flange bolt 4 Heat insulator 5 Outer end face 6 Heat insulator 7 Coolant flow path

Claims (3)

[Claims] 1. A cooling medium flow path is provided between a vertical outer end surface of a horizontal flange of each of an upper half portion and a lower half portion of a vehicle compartment and a heat insulating material coated along the outer end surface. The cooling structure of the steam turbine casing flange. 2. The cooling structure for a steam turbine casing flange according to claim 1, wherein a miscellaneous air pipe is connected to a cooling medium introduction portion of the cooling medium flow path. 3. The cooling medium flow path according to claim 1, wherein a part of the heat insulating material is removed at upper and lower parts of the cooling medium flow path, and the upper and lower parts of the cooling medium flow path are communicated with the atmosphere. Cooling structure of steam turbine casing flange.