JPH11166520A - Bolt device for turbine casing and method of fixing bolt device for turbine casing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bolt device for a turbine casing controlled in not to generate thermal stress exceeding the allowable stress of a bolt material at the time of heating or cooling a bolt, and to provide a method of fixing the bolt device for the turbine casing. SOLUTION: This bolt device for a turbine casing is provided with a bolt body 11 with a center hole 11a provided in an axial direction; a heater 12 inserted in the center hole 11a of the bolt body 11; an inner surface temperature sensor 13 provided at the center hole inner surface 11i of the bolt body 11; and an outer surface temperature sensor 14 provided at a bolt outer surface 11o. A temperature difference detecting device 15 for detecting the temperature difference between the center hole inner surface 11i and bolt outer surface 11o of the bolt body is connected to the inner surface temperature sensor 13 and the outer surface temperature sensor 14. A heater control device 16 for controlling the output of the heater 12 so that the temperature difference is within the tolerance of bolt material is further connected to the temperature difference detecting device 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt device for a turbine casing which is mounted in bolt holes of a pair of turbine casings and fastens the pair of turbine casings, and a method of fixing the bolt device for a turbine casing. TECHNICAL FIELD The present invention relates to a bolt device for a turbine casing and a method for fixing the bolt device for a turbine casing such that excessive thermal stress is not generated in a bolt material during heating or cooling of the bolt.

[0002]

2. Description of the Related Art Generally, in a turbine casing,
In order to prevent leakage of steam inside the casing to the outside,
Many turbine casing bolt devices are installed on the casing horizontal flange portion.

FIG. 7 shows the structure of a conventional bolt device for a turbine casing. As shown in FIG. 7, the bolt device 50 for a turbine casing includes a bolt body 51 provided with a central hole 50 a in an axial direction, and screw portions 51 b, 5
1c is formed.

A bolt device 50 for a turbine casing is
For example, it is used as follows. That is, in order to fasten the pair of casing flanges 61 and 62, the bolt body 51 is continuous with a bolt hole 61a of the upper half casing flange 61 and a bolt hole 62a of the lower half casing flange 62 as shown in FIG. The upper half nut 63 and the lower half nut 64 are inserted into the screw portions 51b and 51c.
Is screwed.

Next, a heater 52 is inserted into the center hole 51a to heat the bolt body 51 from the center hole 51a.
Further, by further screwing the screw portions 51b, 51c, the upper half nut 63, and the lower half nut 64, the bolt body 51 moves the upper half casing flange 61 and the lower half casing flange 62 together with the nuts 63, 64. To conclude. During the fastening process by the screw fastening, the state where the heater 52 is inserted into the center hole 51a is maintained, that is, the fastening by the screw connection is performed while the bolt body 51 is thermally expanded.

[0006] Thereafter, the heating heater 5 is inserted through the center hole 51a.
2, the bolt body 51 is gradually cooled. For this reason, the bolt body 51 that has been thermally expanded contracts, whereby the fastening of the casing flanges 61 and 62 by the bolt body 51 and the nuts 63 and 64 is further strengthened, and the casing flanges 61 and 62 are more tightly sealed. Can be fastened.

In recent years, in order to shorten the time required for disassembling and assembling the turbine, the output of the heater 52 is increased to heat the bolt body 51 in a short time, or after the bolt body 51 is heated, a coolant is supplied to the center hole 51a. The bolt body 51 is forcibly cooled in a short time after being introduced.

[0008]

However, in the conventional bolt device 50 for a turbine casing described above, performing heating or cooling in a short time has the following problems.

As shown in FIG. 8, when the bolt body 51 is heated by a high-power heater 52, the bolt body 51 is heated.
The temperature of the center hole inner surface 51i of the center hole 51a rapidly rises. On the other hand, the temperature rise of the bolt outer surface 51o (the outer surface of the bolt body 51) is caused by the bolt outer surface 5i
It is delayed by the heat transfer time to 1o. For this reason, a temperature difference is generated between the inner surface 51i of the center hole and the outer surface 51o of the bolt, and a compressive stress is generated on the inner surface 51i of the center hole due to the suppression of the thermal expansion. The tensile stress due to the thermal expansion acts.

Conversely, as shown in FIG.
When cooling the bolt body 51 by introducing a refrigerant into the center hole 51a, the temperature of the inner surface 51i of the center hole rapidly drops.
On the other hand, the temperature drop of the bolt outer surface 51o is
Is delayed by the heat transfer time from the bolt outer surface 51o to the center hole inner surface 51i. For this reason, a temperature difference is generated between the inner surface 51i of the center hole and the outer surface 51o of the bolt, and a tensile stress is generated on the inner surface 51i of the center hole by suppressing the restoration of the thermal expansion. Inner surface 51
Compressive stress due to suppression of maintenance of thermal expansion of i acts.

The temperature difference between the inner surface 51i of the center hole and the outer surface 51o of the bolt becomes larger as the heating or cooling is performed more rapidly, and the thickness of the bolt body 51 becomes larger. The longer the distance, the larger the tensile stress and compressive stress (thermal stress)
Is larger as the temperature difference is larger, as shown in FIG. If the tensile stress and the compressive stress exceed the allowable stress range allowed by the material of the bolt body 51, the material of the bolt 51 is deteriorated, and the strength of the bolt body 51 and the life of the bolt body 51 are reduced. I will.

The present invention has been made in view of the above points, and a bolt device for a turbine casing and a turbine in which a thermal stress exceeding an allowable stress of a bolt material is not generated during heating or cooling of the bolt. An object of the present invention is to provide a method for fixing a casing bolt device.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a bolt device for a turbine casing, which is mounted in a bolt hole of a pair of turbine casings and fastens the pair of turbine casings, comprising: a bolt body having a central hole provided in an axial direction; A heating heater inserted into the center hole of the bolt body, an inner surface temperature sensor provided on the inner surface of the center hole of the bolt body, an outer surface temperature sensor provided on the outer surface of the bolt body, an inner surface temperature sensor and an outer surface temperature sensor; And a temperature difference detecting device for detecting a temperature difference between the inner surface of the center hole of the bolt body and the outer surface of the bolt body. The temperature difference is determined based on the temperature difference detected by the temperature difference detecting device. And a heater control device for controlling the output of the heating heater so as to fall within the range.

According to the present invention, the temperature difference detecting device detects the temperature difference between the inner surface of the center hole of the bolt body and the outer surface of the bolt body when the bolt body is heated by the heater, and this temperature difference is used as the bolt material. Since the heater control device controls the output of the heater for heating so as to fall within the allowable range described above, efficient heating control is realized within a range in which thermal stress exceeding the allowable stress of the bolt material is not generated.

According to the present invention, there is provided a bolt device for a turbine casing which is attached to a bolt hole of a pair of turbine casings and fastens the pair of turbine casings, wherein a central hole is provided in an axial direction, and a refrigerant is introduced into the central hole. The main body, the heating device of the bolt body, an inner surface temperature sensor provided on the inner surface of the center hole of the bolt body, an outer surface temperature sensor provided on the outer surface of the bolt body, and connected to the inner surface temperature sensor and the outer surface temperature sensor, A temperature difference detecting device for detecting a temperature difference between the inner surface of the center hole of the bolt body and the outer surface of the bolt body; and based on the temperature difference detected by the temperature difference detecting device, the temperature difference falls within an allowable range of the bolt material. And a refrigerant control device for controlling the amount of refrigerant introduced into the center hole.

According to the present invention, the temperature difference detecting device detects a temperature difference between the inner surface of the center hole of the bolt body and the outer surface of the bolt body when the bolt body is cooled by the refrigerant, and this temperature difference indicates an allowable amount of the bolt material. Since the refrigerant control device controls the amount of refrigerant introduced into the center hole so as to fall within the range, efficient cooling control is realized within a range in which thermal stress exceeding the allowable stress of the bolt material is not generated.

According to the present invention, there is further provided a bolt device for a turbine casing which is attached to bolt holes of a pair of turbine casings and fastens the pair of turbine casings, wherein a central hole is provided in an axial direction, and refrigerant is introduced into the central hole. A bolt body forming an annular refrigerant passage through which a refrigerant is introduced between a pair of turbine casings, a heating device for the bolt body, an inner surface temperature sensor provided on an inner surface of a center hole of the bolt body, and an outer surface of the bolt body. And a center temperature sensor provided at a substantially central thick portion between the inner surface and the outer surface of the center hole, and are connected to the inner surface temperature sensor, the outer surface temperature sensor, and the center temperature sensor. A temperature difference detector for detecting an internal temperature difference between the inner surface and the thick portion of the center hole of the bolt body and an external temperature difference between the thick portion and the outer surface of the bolt body; A refrigerant that controls the amount of refrigerant introduced into the center hole and the annular refrigerant passage based on the internal temperature difference and the external temperature difference detected by the device so that the internal temperature difference and the external temperature difference fall within the allowable range of the bolt material. A control device;
And a bolt device for a turbine casing.

According to the present invention, the temperature difference detecting device detects an internal temperature difference between the inner surface and the thick portion of the center hole of the bolt body and an external temperature difference between the thick portion and the outer surface of the bolt body. Because the refrigerant control device controls the amount of refrigerant introduced into the center hole so that the difference and the outside temperature difference fall within the allowable range of the bolt material,
Efficient cooling control is realized within a range in which thermal stress exceeding the allowable stress of the bolt material is not generated.

According to the present invention, there is provided a method of fixing a bolt device for a turbine casing according to the first aspect of the present invention, wherein a bolt body is inserted into a bolt hole of a pair of turbine casings, and A step of fastening the pair of turbine casings and inserting a heating heater into a center hole of the bolt body to heat the bolt body. The step of fastening the pair of turbine casings and heating the bolt body includes an inner surface temperature sensor. A step of measuring the temperature of the inner surface of the center hole of the bolt body by; and a step of measuring the temperature of the outer surface of the bolt body by an outer surface temperature sensor,
A step of detecting a temperature difference between the inner surface and the outer surface of the center hole of the bolt body by a temperature difference detecting device; and a step of controlling an output of a heating heater by a heater control device based on the temperature difference detected by the temperature difference detecting device. And a method for fixing a bolt device for a turbine casing.

According to the present invention, the temperature difference between the inner surface and the outer surface of the center hole of the bolt body is detected by the temperature difference detecting device, and the heater control device controls the heating heater based on the temperature difference detected by the temperature difference detecting device. Output is controlled,
Efficient heating control is realized in a range in which thermal stress exceeding the allowable stress of the bolt material is not generated.

According to a second aspect of the present invention, there is provided a method for fixing a bolt device for a turbine casing according to the second aspect of the present invention, wherein the step of inserting a bolt body into a bolt hole of a pair of turbine casings comprises the steps of: A step of fastening the pair of turbine casings and heating the bolt body by a heating device, and a step of introducing a coolant into a center hole of the bolt body, wherein the step of introducing the coolant is performed by an inner surface temperature sensor. A step of measuring the temperature of the inner surface of the center hole, a step of measuring the temperature of the outer surface of the bolt body with an outer surface temperature sensor, and a step of detecting the temperature difference between the inner surface and the outer surface of the center hole of the bolt body with a temperature difference detection device, A step of controlling the amount of refrigerant introduced by the refrigerant control device based on the temperature difference detected by the temperature difference detection device,
A method for fixing a bolt device for a turbine casing, comprising:

According to the present invention, the temperature difference between the inner surface and the outer surface of the center hole of the bolt body is detected by the temperature difference detection device, and the refrigerant is introduced by the refrigerant control device based on the temperature difference detected by the temperature difference detection device. Since the amount is controlled, efficient cooling control is realized within a range in which thermal stress exceeding the allowable stress of the bolt material is not generated.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a bolt device for a turbine casing according to a first embodiment of the present invention. As shown in FIG. 1, a bolt device 10 for a turbine casing according to the present embodiment has a center hole 11 a in an axial direction.
, A heating heater 12 inserted into a center hole 11a of the bolt body 11, and an inner surface temperature sensor 1 provided on an inner surface 11i of the center hole of the bolt body 11.
3 and an outer surface temperature sensor 14 provided on the bolt outer surface 11o (the outer surface of the bolt body 11). The inner surface temperature sensor 13 and the outer surface temperature sensor 14 are each configured by a thermocouple sensor.

As shown in FIG. 1, the inner surface temperature sensor 13 and the outer surface temperature sensor 14 are connected to a temperature difference detector 15 for detecting a temperature difference between the inner surface 11a of the center hole of the bolt body 11 and the outer surface 11o of the bolt. The temperature difference detecting device 15 further includes a heater control device that controls the output of the heating heater 12 based on the temperature difference detected by the temperature difference detecting device 15 so that the temperature difference falls within the allowable range of the bolt material. 16 are connected.

Also, as shown in FIG.
The upper and lower outer peripheral surfaces of the
b, 11c are formed. The center hole 11a of the bolt body 11 is provided at the center of the shaft of the bolt body 11.

Next, the operation of the present embodiment having the above configuration will be described. As shown in FIG. 1, first, a bolt body 1 is used to fasten a pair of casing flanges 1 and 2 so that a bolt hole 1 a of an upper half casing flange 1 is formed.
And the lower half casing flange 2a, and the upper half nut 3 and the lower half nut 4 are screwed into the screw portions 11b and 11c.

Next, the heater 12 is inserted into the center hole 11a, and the bolt body 11 is heated from the center hole 11a.
At this time, the temperature of the inner surface 11i of the center hole of the bolt body 11 is measured by the inner surface temperature sensor 13 and the outer surface temperature sensor 14
With this, the temperature of the bolt outer surface 11o is measured. Next, the inner surface 11 of the center hole of the bolt body 11 is detected by the temperature difference detecting device 15.
The temperature difference between i and the bolt outer surface 11o is detected. Based on the temperature difference detected by the temperature difference detecting device 15, the heater controller 16 controls the heating heater 12 so that the temperature difference falls within the allowable range of the bolt material. Is controlled.

Here, the allowable range of the bolt material is determined in advance by the temperature difference between the inner surface 11i of the center hole of the bolt body 11 and the outer surface 11o of the bolt, the thermal stress (tensile stress and compressive stress) caused by the temperature difference, and the bolt material. Is determined by the correlation with the allowable stress. For example, stress σ generally caused by the temperature difference between the inner and outer surfaces of a thick cylindrical bolt can be modeled by the following equation.

Σ = Kb × Km × (Ti−To) (1) Here, Kb is a parameter depending on the shape of the bolt, K
m is a parameter depending on the material of the bolt, To is the outer surface temperature of the bolt, and Ti is the inner surface temperature of the bolt. When this model is adopted, the allowable range of the bolt material with respect to the temperature difference (Ti-To) can be expressed as σa / (Kb × Km) by the equation (1) and the allowable stress σa of the bolt material.
When this relationship is expressed by an equation, the following equation is obtained: Ti−To ≦ σa / (Kb × Km) (2)

During the heating step, the screw portions 11b, 11b
By further tightening the screws c, the upper half nut 3 and the lower half nut 4, the bolt body 11 presses and tightens the upper half casing flange 1 and the lower half casing flange 2. That is, tightening by screw connection is performed in a state where the bolt body 11 is thermally expanded.

Thereafter, the heater 1 is inserted through the central hole 11a.
When 2 is pulled out, the bolt body 11 gradually cools. For this reason, the bolt body 11 that has been thermally expanded contracts, whereby the crimping of the casing flanges 1 and 2 by the bolt body 11 and the nuts 3 and 4 is further strengthened, and the casing flanges 1 and 2 are fastened with higher sealing performance. can do.

According to the present embodiment, the temperature difference detecting device 1
5 is an inner surface 11i of the center hole of the bolt body 11 and an outer surface 11 of the bolt when the bolt body 11 is heated by the heater 12
Since the temperature difference between the bolt and the bolt is controlled by the heater controller 16 so as to control the output of the heater 12 so that this temperature difference falls within the allowable range of the bolt material, the thermal stress exceeding the allowable stress of the bolt material is reduced. Efficient heating control can be performed within a range in which no heating occurs. Therefore, the construction period is shortened, and the bolt body 1 is exposed to thermal stress exceeding the allowable stress range.
1 prevents deterioration in material strength and life due to deterioration of the material, and improves the reliability of casing fixing by the turbine casing bolt device 10.

The diameter of the center hole 11a and the center hole 1
The outer diameter of the heating heater 12 inserted into the bolt 1a is not limited at all, but in order to heat the bolt body 11 in a shorter time, the diameter of the center hole 11a is increased, and
It is desirable to increase the heat transfer efficiency by enlarging the outer diameter at approximately the same rate. Further, as the output of the heating heater 12, a maximum output within a range in which a thermal stress exceeding the allowable stress of the bolt material is not generated can be used. In some cases, it is possible to use a heater output that is two to three times the conventional one. .

Next, referring to FIG. 2, a description will be given of a bolt device for a turbine casing according to a second embodiment of the present invention. In FIG. 2, a bolt device 10 for a turbine casing according to the second embodiment is configured such that a refrigerant is introduced into a center hole 11a, and is detected by a temperature difference detection device 15 instead of the heater control device 16. Based on the temperature difference between the inner surface 11i of the center hole and the outer surface 11o of the bolt, a refrigerant control device 17 is provided which controls the amount of refrigerant introduced into the center hole 11a such that the temperature difference falls within the allowable range of the bolt material. . Other configurations are substantially the same as those of the first embodiment shown in FIG. In the second embodiment, the same parts as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description is omitted.

Next, the operation of the present embodiment having the above configuration will be described. As shown in FIG. 2, first, the bolt body 11 is used to fasten the pair of casing flanges 1 and 2 so that the bolt holes 1 a of the upper half casing flange 1 are fastened.
And the lower half casing flange 2a, and the upper half nut 3 and the lower half nut 4 are screwed into the screw portions 11b and 11c.

Next, the heater 12 is inserted into the center hole 11a, and the bolt body 11 is heated from the center hole 11a.
During this heating step, the screw body 11b, 11c, the upper half nut 3, and the lower half nut 4 are further screwed, so that the bolt body 11 crimps the upper half casing flange 1 and the lower half casing flange 2. And conclude. That is, tightening by screw connection is performed in a state where the turbine casing bolt 11 is thermally expanded.

Thereafter, the heating heater 1 is inserted through the center hole 11a.
2 is drawn out, and the refrigerant is introduced into the center hole 11 a of the bolt body 11. As the refrigerant, those having various aspects such as cooling water and cooling air are used. The introduction of the refrigerant is performed by inserting the finned tube 18 into the center hole 11a with the fin 18a in contact with the inner surface 11i of the center hole, and introducing the refrigerant into the finned tube 18. With the introduction of the refrigerant, the bolt body 11 that has been thermally expanded is cooled and contracted.
1 and casing flanges 1 and 2 by nuts 3 and 4
Is further strengthened, and the casing flanges 1 and 2 can be fastened with higher hermeticity.

At this time, the temperature of the inner surface 11i of the center hole of the bolt body 11 is measured by the inner surface temperature sensor 13, the temperature of the bolt outer surface 11o is measured by the outer surface temperature sensor 14, and the center of the bolt body 11 is measured by the temperature difference detector 15. The temperature difference between the hole inner surface 11i and the bolt outer surface 11o is detected. Next, based on the temperature difference detected by the temperature difference detection device 15, the refrigerant control device 17 controls the amount of refrigerant introduced into the center hole 11a so that the temperature difference falls within the allowable range of the bolt material. For example, a valve or the like of a supply path for supplying cooling water or cooling air is controlled.

Here, the allowable range of the bolt material is determined in advance by the temperature difference between the inner surface 11i of the center hole of the bolt body 11 and the outer surface 11o of the bolt, the thermal stress (tensile stress and compressive stress) caused by the temperature difference, and the bolt material. (See equations (1) and (2)).

According to the present embodiment, the temperature difference detecting device 1
5 detects the temperature difference between the inner surface 11i of the center hole of the bolt body 11 and the outer surface 11o of the bolt when the bolt body 11 is cooled by the refrigerant, and the refrigerant controller 17 determines that the temperature difference is within the allowable range of the bolt material. The central hole 11a of the refrigerant to enter
Therefore, efficient cooling control can be performed within a range in which thermal stress exceeding the allowable stress of the bolt material is not generated. Therefore, the construction period is shortened,
Material deterioration of the bolt main body 11 due to thermal stress exceeding the allowable stress range is prevented, thereby reducing the strength and life, and the reliability of fixing the casing by the turbine casing bolt device 10 is improved.

According to the present embodiment, the center hole 11
Since the finned tube 18 is inserted into the finned tube 18 with the fin 18a in contact with the center hole inner surface 11i and the refrigerant is introduced into the finned tube 18, the substantial contact area between the center hole inner surface 11i and the refrigerant is reduced. It is possible to obtain an increased cooling effect. Further, as shown in FIG.
It is also possible to insert the refrigerant into the gap formed between the tube 1a and the finned tube 18, and in this case, the cooling effect can be further enhanced.

Next, referring to FIGS. 4 and 5, a description will be given of a turbine casing bolt device according to a third embodiment of the present invention. 4 and 5, in the bolt device 10 for a turbine casing according to the third embodiment, the bolt body 11 has additional coolant holes 11e, 11f, 11g, and 11h that form a coolant passage in addition to the center hole 11a. It is configured to have. Other configurations are substantially the same as those of the second embodiment shown in FIG. In the third embodiment, the same portions as those of the second embodiment shown in FIG. 2 are denoted by the same reference numerals, and detailed description is omitted.

Additional refrigerant holes 11e, 11f, 11g, 11
As shown in FIG. 4 and FIG. 5, h is provided in a thick portion substantially in the circumferential direction and substantially at the center between the center hole 11a of the bolt body 11 and the bolt outer surface 11o.

In the present embodiment, when the heater 12 is drawn out from the center hole 11a and the refrigerant is introduced into the center hole 11a of the bolt body 11, the additional refrigerant hole 11
Refrigerants are also introduced into e, 11f, 11g, and 11h. Therefore, the bolt body 11 that has been thermally expanded is cooled more rapidly and contracts. As a result, the pressure of the casing flanges 1 and 2 by the bolt body 11 and the nuts 3 and 4 is further strengthened, and the casing flanges 1 and 2 can be fastened with higher hermeticity. At this time, the temperature of the inner surface 11i of the center hole of the bolt main body 11 is measured by the inner surface temperature sensor 13 and the outer surface temperature sensor 14 measures the temperature of the bolt outer surface 11i.
o, the temperature difference between the inner surface 11i of the center hole of the bolt body 11 and the outer surface 11o of the bolt is detected by the temperature difference detection device 15, and based on the temperature difference detected by the temperature difference detection device 15, The refrigerant control device 17 controls the center hole 11 of the refrigerant so that the difference falls within the allowable range of the bolt material.
a and the amounts of introduction into the additional refrigerant holes 11e, 11f, 11g, and 11h are controlled.

Here, the allowable range of the bolt material is determined in advance by the temperature difference between the inner surface 11a of the center hole of the bolt body 11 and the outer surface 11o of the bolt, the thermal stress (tensile stress and compressive stress) caused by the temperature difference, the bolt material, and the like. Is determined by the correlation with the allowable stress.

According to the present embodiment, the temperature difference detecting device 1
5 detects the temperature difference between the inner surface 11i of the center hole of the bolt body 11 and the outer surface 11o of the bolt when the bolt body 11 is cooled by the refrigerant, and the refrigerant controller 17 determines that the temperature difference is within the allowable range of the bolt material. The central hole 11a of the refrigerant to enter
In addition, since the amount of introduction into the additional refrigerant holes 11e, 11f, 11g, and 11h is controlled, efficient cooling control can be performed within a range in which thermal stress exceeding the allowable stress of the bolt material is not generated. Accordingly, the construction period is shortened, and the deterioration of the strength and the life due to the material deterioration of the bolt body 11 due to the thermal stress exceeding the allowable stress range is prevented, and the reliability of the casing fixing by the turbine casing bolt device 10 is reduced. improves.

Further, according to the present embodiment, the provision of the additional refrigerant holes 11e, 11f, 11g, 11h
Since the cooling source is set at a plurality of locations, the bolt body 1
1 can be cooled more rapidly, and the temperature difference between the inner surface 11i of the center hole of the bolt body 11 and the outer surface 11o of the bolt can be reduced. This effect can be further enhanced by appropriately adjusting the positions and numbers of the additional coolant holes 11e, 11f, 11g, and 11h in accordance with the dimensions of the bolt body 11.

Next, referring to FIG. 6, a description will be given of a bolt device for a turbine casing according to a fourth embodiment of the present invention. 6, the turbine casing bolt device 10 of the fourth embodiment has an annular refrigerant passage 20 through which a refrigerant is introduced between a bolt body 11 and a pair of turbine casings 1 and 2. Center hole 11
A central temperature sensor 21 is provided at a thick portion 11m substantially at the center between the bolt body 11a and the bolt outer surface 11o, and the temperature difference detecting device 15 detects the internal temperature difference between the center hole inner surface 11i of the bolt body 11 and the thick portion 11m and the bolt body. It is configured to detect an external temperature difference between the thick portion 11m of the eleventh portion and the bolt outer surface 11o.
Further, the refrigerant control device 17 determines the center hole 1 of the refrigerant based on the internal temperature difference and the external temperature difference detected by the temperature difference detection device 15 so that the temperature difference falls within the allowable range of the bolt material.
1a and the amount of introduction into the annular refrigerant passage 20 is controlled. Other configurations are substantially the same as those of the second embodiment shown in FIG. In the fourth embodiment,
The same parts as those in the second embodiment shown in FIG. 2 are denoted by the same reference numerals, and detailed description is omitted.

Next, the operation of the present embodiment having the above configuration will be described. As shown in FIG. 6, first, the bolt body 11 is used to fasten the pair of casing flanges 1 and 2 so that the bolt hole 1a of the upper half casing flange 1 is formed.
And 2a of the lower casing flange 2 continuously, and the washer 22 is sandwiched between the threaded portions 11b and 11c.
The upper half nut 3 and the lower half nut 4 are screwed. Here, the washer 22 has a refrigerant introduction hole 22a penetrating from the outer surface to the inner surface. The annular refrigerant passage 20 communicates with the outer surface of the washer through the refrigerant introduction hole 22a. As shown in FIG. 6, the refrigerant introduction hole 22a may be provided horizontally or may be provided at an angle.

Next, the heater 12 is inserted into the center hole 11a, and the bolt body 11 is heated from the center hole 11a.
During this heating step, the screw body 11b, 11c, the upper half nut 3, and the lower half nut 4 are further screwed, so that the bolt body 11 crimps the upper half casing flange 1 and the lower half casing flange 2. And conclude. That is, tightening by screw connection is performed in a state where the turbine casing bolt 11 is thermally expanded.

Thereafter, the heater 1 is inserted through the center hole 11a.
2 is drawn out, and the refrigerant is introduced into the center hole 11a of the bolt body 11 and the refrigerant introduction hole 22a of the washer 22. The refrigerant introduced into the refrigerant introduction hole 22 a passes through the annular refrigerant passage 20. With the introduction and passage of the refrigerant, the thermally expanded bolt body 11 is cooled and contracted, whereby the press-fitting of the casing flanges 1 and 2 by the bolt body 11 and the nuts 3 and 4 is further strengthened, and higher sealing performance is achieved. , The casing flanges 1 and 2 can be fastened.

At this time, the temperature of the inner surface 11i of the center hole of the bolt body 11 is measured by the inner surface temperature sensor 13, the temperature of the bolt outer surface 11o is measured by the outer surface temperature sensor 14, and the thickness of the bolt body 11 is measured by the central temperature sensor 21. The temperature of the portion 11m is measured, and the temperature difference detector 15 detects the temperature difference between the inner surface 11i of the center hole of the bolt body 11 and the thick portion 11m and the thick portion 11m of the bolt body and the outer surface 1 of the bolt.
An outside temperature difference from 1o is detected. Next, the temperature difference detection device 1
5 based on the inside temperature difference and the outside temperature difference detected by the refrigerant control device 17 so that these temperature differences fall within the respective allowable ranges of the bolt material.
a and the refrigerant introduction hole 22a, that is, the amount of introduction into the annular refrigerant passage 20 is controlled.

Here, the allowable range of the bolt material is determined in advance by the internal temperature difference between the inner surface 11i of the center hole of the bolt body 11 and the thick portion 11m of the bolt body 11 and the thick portion 11m of the bolt body 11 and the bolt outer surface 11o. Temperature difference and thermal stress (tensile and compressive stress) caused by the temperature difference
And the allowable stress of the bolt material. For example, stress σ generally caused by a temperature difference between the surface (inner surface and outer surface) of a thick cylindrical bolt and the inside of the bolt
1 (inner side) and σ2 (outer side) can be modeled by the following equations. σ1 = Kb1 × Km × (Tc−To) (3) σ2 = Kb2 × Km × (Tc−Ti) (4) where Kb1 and Kb2 are parameters dependent on the shape of the bolt, Km Is a parameter dependent on the material of the bolt, T
c is the internal temperature of the bolt, To is the external temperature of the bolt, Ti
Is the inner surface temperature of the bolt. When this model is adopted, the allowable range of the bolt material with respect to the temperature difference (Tc-To) and (Tc-Ti) is σa according to the equations (3) and (4) and the allowable stress σa of the bolt material. /
(Kb1 × Km) and σa / (Kb2 × Km). When this relationship is expressed by an equation, Tc−To ≦ σa / (Kb1 × Km) (5) Tc−Ti ≦ σa / (Kb2 × Km) (6)

According to the present embodiment, the temperature difference detecting device 1
5 is the internal temperature difference between the inner surface 11i of the center hole of the bolt body 11 and the thick portion 11m of the bolt body 11 when the bolt body 11 is cooled by the refrigerant, and the thick portion 1 of the bolt body 11
The refrigerant control device 17 detects an external temperature difference between 1 m and the bolt outer surface 11o, and introduces the refrigerant into the center hole 11a and the refrigerant introduction hole 22a such that the temperature difference falls within each allowable range of the bolt material. Since the amount is controlled, efficient cooling control can be performed within a range in which thermal stress exceeding the allowable stress of the bolt material is not generated. Accordingly, the construction period is shortened, and the deterioration of the strength and the life due to the material deterioration of the bolt body 11 due to the thermal stress exceeding the allowable stress range is prevented, and the reliability of the casing fixing by the turbine casing bolt device 10 is reduced. improves.

Further, according to the present embodiment, the formation of the annular refrigerant passage 20 allows the bolt body 11 to be cooled from both the inner surface 11i of the center hole and the outer surface 11o of the bolt. Not only can it be performed more rapidly, but also
making the temperature difference between i and the bolt outer surface 11o essentially zero;
It is possible to reduce the temperature difference generated in the bolt main body 11.

[0056]

As described above, according to the present invention, the temperature difference detection device detects the temperature difference between the inner surface of the center hole of the bolt body and the outer surface of the bolt when the bolt body is heated by the heater.
The heater control device controls the output of the heating heater so that the temperature difference falls within the allowable range of the bolt material.
Efficient heating control is realized within a range where thermal stress exceeding the allowable stress of the bolt material is not generated, shortening the construction period, and causing heat deterioration exceeding the allowable stress range to cause material deterioration in the bolt body and increase strength and strength. The service life is prevented from being shortened, and the reliability of fixing the casing by the bolt device for the turbine casing is improved.

Further, according to the present invention, the temperature difference detecting device detects the temperature difference between the inner surface of the center hole of the bolt body and the outer surface of the bolt when the bolt body is cooled by the refrigerant, and this temperature difference is determined by the allowable range of the bolt material. Refrigerant control device controls the amount of refrigerant introduced into the center hole so that cooling can be efficiently performed within the range where thermal stress exceeding the allowable stress of bolt material does not occur, shortening the construction period In addition to the above, it is possible to prevent the material deterioration of the bolt body due to the thermal stress exceeding the allowable stress range, thereby preventing the strength and the life from being reduced,
The reliability of fixing the casing by the turbine casing bolt device is improved.

According to the present invention, the temperature difference detecting device detects an internal temperature difference between the inner surface of the center hole of the bolt body and the thick portion and an external temperature difference between the thick portion of the bolt body and the outer surface of the bolt. By controlling the amount of refrigerant introduced into the center hole by the refrigerant control device so that the internal temperature difference and the external temperature difference fall within the allowable range of the bolt material, the efficiency can be reduced within a range where thermal stress exceeding the allowable stress of the bolt material does not occur. Since good cooling control is realized, the construction period is shortened, and the deterioration of the strength and life due to the material deterioration of the bolt body due to the thermal stress exceeding the allowable stress range is prevented. The reliability of fixing is improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of a bolt device for a turbine casing according to the present invention.

FIG. 2 is a schematic sectional view showing a second embodiment of a bolt device for a turbine casing according to the present invention.

FIG. 3 is a schematic sectional view corresponding to FIG. 2 when a refrigerant introduction method is changed.

FIG. 4 is a schematic sectional view showing a third embodiment of a bolt device for a turbine casing according to the present invention.

FIG. 5 is a view of the bolt body shown in FIG.

FIG. 6 is a schematic sectional view showing a fourth embodiment of a bolt device for a turbine casing according to the present invention.

FIG. 7 is a schematic sectional view showing a configuration of a conventional bolt for a turbine casing.

FIG. 8 is a diagram showing a relationship among heating / cooling time, inner and outer surface temperatures, and thermal stress in a conventional turbine casing bolt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper half casing flange 2 Lower half casing flange 3 Upper nut 4 Lower nut 10 Bolt device for turbine casing 11 Bolt body 11a Center hole 11b, 11c Screw part 11e, 11f, 11g, 11h Additional refrigerant hole 12 Heating heater 13 Inner surface temperature Sensor 14 Outer surface temperature sensor 15 Temperature detector 16 Heater controller 17 Refrigerant controller 18 Tube with fin 18a Fin 20 Annular refrigerant passage 21 Central temperature sensor 22 Washer 22a Refrigerant introduction hole

Claims (8)

[Claims] 1. A bolt device for a turbine casing which is attached to bolt holes of a pair of turbine casings and fastens the pair of turbine casings, a bolt body having a central hole provided in an axial direction, and a bolt body inserted into the central hole of the bolt body. A heater for heating, an inner surface temperature sensor provided on the inner surface of the center hole of the bolt body, an outer surface temperature sensor provided on the outer surface of the bolt body, and an inner surface temperature sensor and an outer surface temperature sensor connected to the center of the bolt body. A temperature difference detection device for detecting a temperature difference between the inner surface of the hole and the outer surface of the bolt body; and a temperature difference detected by the temperature difference detection device.
A heater control device for controlling an output of the heater for heating such that the temperature difference falls within an allowable range of the bolt material. 2. A bolt device for a turbine casing which is attached to bolt holes of a pair of turbine casings and fastens the pair of turbine casings, a bolt body having a central hole in an axial direction, and a refrigerant being introduced into the central hole. A heating device for the bolt body, an inner surface temperature sensor provided on the inner surface of the center hole of the bolt body, an outer surface temperature sensor provided on the outer surface of the bolt body, and an inner surface temperature sensor and an outer surface temperature sensor connected to the bolt body; A temperature difference detection device that detects a temperature difference between the inner surface of the center hole and the outer surface of the bolt body; and, based on the temperature difference detected by the temperature difference detection device,
A bolt device for a turbine casing, comprising: a refrigerant control device that controls an amount of refrigerant introduced into a center hole so that the temperature difference falls within an allowable range of the bolt material. 3. The bolt device for a turbine casing according to claim 2, wherein the bolt body has an additional coolant hole that forms a coolant passage in addition to the center hole. 4. A turbine casing bolt device mounted on bolt holes of a pair of turbine casings and fastening the pair of turbine casings, wherein a central hole is provided in an axial direction, a refrigerant is introduced into the central hole, and A bolt body forming an annular refrigerant passage through which a refrigerant is introduced between the turbine casing, a heating device for the bolt body, an inner surface temperature sensor provided on an inner surface of a center hole of the bolt body, and an outer surface of the bolt body. An inner surface temperature sensor, an outer surface temperature sensor, and a central temperature sensor provided at a substantially central thick portion between the inner surface of the center hole of the bolt body and the outer surface of the bolt body. Temperature difference detecting device for detecting the internal temperature difference between the inner surface and the thick portion of the center hole of the bolt body and the external temperature difference between the thick portion and the outer surface of the bolt body. Based on the internal temperature difference and the external temperature difference detected by the temperature difference detection device, introducing the refrigerant into the center hole and the annular refrigerant passage such that the internal temperature difference and the external temperature difference fall within the allowable range of the bolt material. A bolt device for a turbine casing, comprising: a refrigerant control device that controls an amount. 5. The method for fixing a bolt device for a turbine casing according to claim 1, wherein a step of inserting a bolt body into a bolt hole of the pair of turbine casings, the step of fastening the pair of turbine casings by the bolt body, and Heating the bolt body by inserting a heating heater into the center hole of the body, and fastening the pair of turbine casings and heating the bolt body, wherein the temperature of the inner surface of the center hole of the bolt body is measured by an inner surface temperature sensor. Measuring, measuring the temperature of the outer surface of the bolt body with the outer surface temperature sensor, detecting the temperature difference between the inner surface and the outer surface of the center hole of the bolt body with the temperature difference detecting device, detecting with the temperature difference detecting device Controlling the output of the heater for heating by the heater control device based on the determined temperature difference. Method for fixing a bolt device for a turbine casing. 6. A method of fixing a bolt device for a turbine casing according to claim 2, wherein a step of inserting a bolt body into a bolt hole of the pair of turbine casings, the step of fastening the pair of turbine casings by the bolt body, and A step of heating the main body by a heating device; and a step of introducing a refrigerant into a center hole of the bolt main body.The step of introducing the refrigerant includes a step of measuring the temperature of the inner surface of the center hole of the bolt main body with an inner surface temperature sensor. Measuring the temperature of the outer surface of the bolt body with the outer surface temperature sensor; detecting the temperature difference between the inner surface and the outer surface of the center hole of the bolt body with the temperature difference detecting device; and detecting the temperature difference detected by the temperature difference detecting device. Controlling the amount of refrigerant introduced by the refrigerant control device based on the turbine casing. The method of fixing the winding device. 7. A step of introducing a refrigerant into the center hole of the bolt body, a step of inserting a finned tube into the center hole with the fins in contact with the inner surface of the center hole, and inserting a refrigerant into the finned tube. The method for fixing a bolt device for a turbine casing according to claim 6, further comprising: 8. The step of introducing refrigerant into the center hole of the bolt body further comprises the step of inserting refrigerant into a gap formed between the center hole and the finned tube. Item 8. A method for fixing a bolt device for a turbine casing according to Item 7.