Gas turbine and method for assembling a gas turbine

Abstract

To provide a gas turbine capable of efficient assembly and maintenance, and an assembly method for gas turbine.SOLUTION: A gas turbine has: a rotor rotatable around an axial line and communicable power to a power generator; a plurality of tachometers capable of independently measuring rotary speed of the rotor; and a rotor cover which covers at least a part of the rotor from an outer periphery side and has a plurality of fitting parts that can be fitted respectively so that the plurality of tachometers face the axial line. On an outer peripheral surface of the rotor, recesses and projections to be used for measuring rotary speed are provided alternately in a circumferential direction. A phase difference in the circumferential direction of the plurality of fitting parts is an integral multiple of a phase difference between two adjacent projections in the rotor.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a gas turbine and a method for assembling a gas turbine.

Background Art

[0002] A gas turbine includes a rotor rotatable about an axis. A generator is directly or indirectly connected to an axial end of the rotor (for example, Patent Document 1 below). A tachometer is used to measure the rotational speed of the rotor. The tachometer is, for example, a proximity sensor. The tachometer is arranged radially so as to face the outer peripheral surface of the rotor. Recesses and protrusions are formed on the outer peripheral surface of the rotor and arranged alternately in the circumferential direction. The tachometer measures the rotational speed of the rotor from waveforms obtained as the recesses and protrusions pass by. It is common to provide a plurality of tachometers spaced apart in the circumferential direction.

[0003] By the way, in order to realize accurate measurement by the tachometer, it is necessary to adjust the separation distance (gap) between the tip of the tachometer and the protrusion of the rotor described above. That is, it is necessary to perform this gap adjustment for all of the plurality of tachometers.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, conventionally, the circumferential position (phase) where the tachometer is provided and the circumferential position (phase) of the protrusion of the rotor do not match. For this reason, every time the gap of one tachometer is adjusted, an operation of rotating the rotor to align the tip of the tachometer and the protrusion has occurred. As a result, there has been a problem that the efficiency of the assembly work and maintenance work of the gas turbine is reduced.

[0006] This disclosure was made to solve the above-mentioned problems and aims to provide a gas turbine and a gas turbine assembly method that enable more efficient assembly and maintenance. [Means for solving the problem]

[0007] To solve the above problems, the gas turbine according to this disclosure comprises a rotor that is rotatable around an axis and capable of transmitting power to a generator, a plurality of tachometers capable of independently measuring the rotational speed of the rotor, and a rotor cover that covers at least a part of the rotor from the outer circumference and has a plurality of mounting parts to which the plurality of tachometers can be mounted so as to face the axis, wherein the outer surface of the rotor is alternately provided with recesses and protrusions in the circumferential direction for measuring the rotational speed, and the circumferential phase difference of the plurality of mounting parts is an integer multiple of the phase difference of two adjacent protrusions on the rotor. Furthermore, the circumferential positions of the multiple mounting parts are within a range of ±45° with respect to the horizontal direction.

[0008] The gas turbine assembly method according to the present disclosure is a gas turbine assembly method, comprising the steps of: attaching the tachometer to each of the plurality of mounting parts; rotating the rotor around the axis to align the phase of each tachometer with each of the protrusions; and adjusting the distance between each tachometer and each of the protrusions. [Effects of the Invention]

[0009] This disclosure provides a gas turbine that can be assembled and maintained more efficiently, and a method for assembling a gas turbine. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the configuration of a gas turbine according to an embodiment of this disclosure. [Figure 2] This is an enlarged cross-sectional view of a key part of a gas turbine according to the present disclosure. [Figure 3]This is a cross-sectional view showing the relationship between a tachometer and a rotor according to an embodiment of the present disclosure. [Figure 4] This is a flowchart showing each step of the gas turbine assembly method according to the embodiment of this disclosure. [Figure 5] This is a cross-sectional view showing a modified example of a rotor according to the present disclosure. [Modes for carrying out the invention]

[0011] Hereinafter, a gas turbine 1 and a method for assembling the gas turbine 1 according to the embodiments of this disclosure will be described with reference to Figures 1 to 4.

[0012] (Gas turbine configuration) As shown in Figure 1, the gas turbine 1 comprises a compressor 10, a combustor 20, a turbine 30, and a tachometer 40.

[0013] The compressor 10 compresses air to produce high-pressure air. The compressor 10 includes a compressor rotor 11, a plurality of compressor blade rows 12, a compressor casing 13, and a plurality of compressor stator blade rows 14. The compressor rotor 11 is columnar in shape with axis O as its center. The compressor rotor 11 is supported so as to be rotatable around axis O. Multiple compressor blade rows 12 are provided on the outer circumferential surface of the compressor rotor 11, arranged at intervals in the direction of axis O. Each compressor blade row 12 has multiple compressor blades 15 that extend radially and are arranged at intervals in the circumferential direction.

[0014] These multiple compressor rotor blade rows 12 are covered from the outer periphery by a compressor casing 13. The compressor casing 13 is cylindrical with an axis O as its center. Multiple compressor stator blade rows 14 are provided on the inner circumferential surface of the compressor casing 13, arranged at intervals in the direction of axis O. Each compressor stator blade row 14 has multiple compressor stator blades 16 that extend radially and are arranged at intervals in the circumferential direction.

[0015] The combustor 20 is attached to an intermediate casing 21 provided on the downstream side in the direction of the axis O of the compressor casing 13. The combustor 20 mixes fuel with the high-pressure air generated by the compressor 10 and burns it to generate high-temperature and high-pressure combustion gas. A plurality of combustors 20 are provided at intervals in the circumferential direction with respect to the axis O. The combustion gas generated by the combustor 20 is sent into a turbine casing 33, which will be described later.

[0016] The turbine 30 includes a turbine rotor 31, a plurality of turbine rotor blade rows 32, a turbine casing 33, and a plurality of turbine stator blade rows 34. The turbine rotor 31 has a columnar shape centered on the axis O. The turbine rotor 31 is supported so as to be rotatable about the axis O. A plurality of turbine rotor blade rows 32 arranged at intervals in the direction of the axis O are provided on the outer peripheral surface of the turbine rotor 31. Each turbine rotor blade row 32 has a plurality of turbine rotor blades 35 that extend in the radial direction and are arranged at intervals in the circumferential direction.

[0017] These plurality of turbine rotor blade rows 32 are covered from the outer peripheral side by the turbine casing 33. The turbine casing 33 has a cylindrical shape centered on the axis O. A plurality of turbine stator blade rows 34 arranged at intervals in the direction of the axis O are provided on the inner peripheral surface of the turbine casing 33. Each turbine stator blade row 34 has a plurality of turbine stator blades 36 that extend in the radial direction and are arranged at intervals in the circumferential direction.

[0018] The above-described compressor rotor 11 and turbine rotor 31 are integrally connected to each other on the axis O to form a gas turbine rotor 91 (rotor). The compressor casing 13, the intermediate casing 21, and the turbine casing 33 are integrally connected in the direction of the axis O to form a gas turbine casing 92. That is, the gas turbine rotor 91 is rotatable integrally about the axis O within the gas turbine casing 92.

[0019] When the gas turbine rotor 91 is rotated by an electric motor or the like not shown, air is taken into the compressor 10. By driving the compressor 10, high-pressure air is generated. The high-pressure air generated by the compressor 10 is sent from the compressor casing 13 to the combustor 20 in the intermediate casing 21. The combustor 20 generates high-temperature and high-pressure combustion gas by mixing fuel with the high-pressure air and burning it. The combustion gas is sent into the turbine casing 33 and gives rotational energy to the turbine rotor 31. By such continuous operation, the gas turbine 1 is operated.

[0020] A generator 60 is connected to the shaft end of the gas turbine rotor 91 via a coupling 50. The generator 60 may be connected coaxially with the gas turbine rotor 91 on the axis O, or may be arranged on another axis parallel to the axis O. Further, another rotating machine such as a steam turbine may be interposed between the generator 60 and the gas turbine 1.

[0021] As shown in FIG. 2, the coupling 50 includes a first flange 51 provided at the shaft end of the gas turbine rotor 91, a second flange 62 provided on the generator rotor 61 provided on the generator 60 and facing the first flange 51 in the direction of the axis O, and a rotor cover 70 that covers the first flange 51 and the second flange 6 together from the outer peripheral side. The first flange 51 and the second flange 62 are in the shape of a disk centered on the axis O. The diameter dimensions of the first flange 51 and the second flange 62 are larger than the diameter dimensions of the gas turbine rotor 91 and the generator rotor 61. The first flange 51 and the second flange 62 are fastened and fixed to each other by bolts and nuts not shown. That is, the gas turbine rotor 91 and the generator rotor 61 can rotate integrally around the axis O. Thereby, the power of the gas turbine rotor 91 can be transmitted to the generator 60.

[0022] The rotor cover 70 is cylindrical with axis O as its center. A mounting portion 71 for attaching a tachometer 40 is formed in a portion of the rotor cover 70 in the circumferential direction. The mounting portion 71 is a hole (insertion hole 72) that penetrates the rotor cover 70 radially. The tachometer 40 is held in place by being inserted into this insertion hole 72 from the radially outside. The tachometer 40 is, for example, a proximity sensor or a laser positioning meter.

[0023] On the outer circumferential surface of the first flange 51, in the region facing the gas turbine 1, a plurality of recesses 52 and a plurality of protrusions 53 are formed, arranged alternately in the circumferential direction. When viewed from the direction of axis O, the recesses 52 are rectangular indentations extending radially inward from the outer circumferential surface of the first flange 51. The protrusions 53 are the portions enclosed by two adjacent recesses 52. In other words, when viewed from the direction of axis O, the protrusions 53 have a rectangular cross-sectional shape. Note that the region in which these recesses 52 and protrusions 53 are formed can be any position on the outer circumferential surface of the first flange 51.

[0024] The regions where these recesses 52 and protrusions 53 are formed coincide with the mounting portion 71 of the rotor cover 70 and the tachometer 40 in the direction of axis O. In other words, the tip of the tachometer 40 faces these recesses 52 and protrusions 53 from the radially outer side. The tachometer 40 detects the timing when the protrusions 53 pass over the gas turbine rotor 91 as it rotates, and measures and outputs the rotational speed of the gas turbine rotor 91 based on the length of the detection interval. Multiple tachometers 40 operate independently of each other. In other words, even if one tachometer 40 becomes inoperable due to a malfunction or the like, the remaining tachometers 40 can continue to measure the rotational speed.

[0025] As shown in Figure 3, multiple tachometers 40 are provided at intervals in the circumferential direction. Here, a first virtual line L1 is defined that passes through the axis O and extends horizontally, and a second virtual line L2 passes through the axis O and is perpendicular to the first virtual line L1. These first and second virtual lines L1 and L2 divide the region around the axis O into four sections. One or more tachometers 40 are provided in each of these four circumferential regions. In other words, multiple tachometers 40 are distributed across the four circumferential regions. The example in Figure 3 shows a case where a total of six tachometers 40 are provided, but the number of tachometers 40 is not limited to six; it may be five or fewer, or seven or more. However, it is desirable to have three or more tachometers 40. Also, it is not necessarily required to provide a tachometer 40 in each of the four circumferential regions, but it is desirable to place them in two or more circumferential regions.

[0026] Furthermore, a third virtual line L3 and a fourth virtual line L4 are set, intersecting the first virtual line L1 and the second virtual line L2 at a 45° angle. In this case, it is desirable that the circumferential position where the tachometer 40 is installed is the region enclosed by the third virtual line L3 and the fourth virtual line L4, with respect to the first virtual line L1. In other words, it is desirable that the tachometer 40 be positioned in a circumferential region of 45° above and below the first virtual line L1. To put it another way, it is desirable that the tachometer 40 be positioned in a circumferential region of ±45° above and below the horizontal direction.

[0027] In addition, the circumferential spacing (referred to as the phase difference) between the tachometer 40 and the mounting portion 71 is set to an integer multiple of the circumferential spacing (phase difference) between two adjacent protrusions 53 on the first flange 51. In other words, if the radially inward tip of any one tachometer 40 faces one protrusion 53, the remaining tachometers 40 and their corresponding protrusions 53 are also facing each other simultaneously.

[0028] (Gas turbine assembly method) Next, with reference to Figure 4, the assembly method of the gas turbine 1 according to this embodiment will be described. As shown in the figure, this assembly method includes the step S1 of installing the tachometer 40, the step S2 of rotating the gas turbine rotor 91, and the step S3 of adjusting the gap (separation distance) between the tachometer 40 and the protrusion 53.

[0029] In step S1, the tachometers 40 are attached to the insertion holes 72, which serve as the mounting portions 71 described above. Then, in step S2, the gas turbine rotor 91 is rotated slightly around the axis O. At this time, the gas turbine rotor 91 is rotated until the tip of the tachometer 40 and one of the protrusions 53 of the first flange 51 face each other radially. After going through step S2, all the tachometers 40 are in a state where they face each other radially with respect to the protrusions 53. Next, in step S3, the gap between each tachometer 40 and the protrusions 53 is adjusted. That is, the radial position of the tachometers 40 is adjusted so that there is an appropriate gap for measuring the rotational speed. With this, all the steps of the assembly method for the gas turbine 1 are completed.

[0030] (Effects and Benefits) Conventionally, the circumferential position (phase) of the tachometer 40 and the circumferential position (phase) of the rotor's protrusion 53 did not coincide. In other words, the phase difference of the protrusion 53 was not considered when determining the circumferential position of the tachometer 40. As a result, each time the gap of one tachometer 40 was adjusted, the rotor had to be rotated slightly to align the tip of another tachometer 40 with the protrusion 53. This resulted in a decrease in the efficiency of gas turbine assembly and maintenance work. Therefore, in order to solve this problem, the above configuration and method are adopted in this embodiment.

[0031] With the above configuration, the circumferential phase difference between the multiple mounting parts 71 and the tachometer 40 is an integer multiple of the phase difference between two adjacent protrusions 53. Therefore, if the circumferential position of any one tachometer 40 and one protrusion 53 coincides, the circumferential positions of the remaining tachometers 40 and their corresponding protrusions 53 will also coincide. In other words, by rotating the gas turbine rotor 91 only once, it is possible to align the circumferential positions of all the tachometers 40 and protrusions 53. This eliminates the need to rotate the gas turbine rotor 91 each time the gap of the tachometer 40 is adjusted, thereby improving work efficiency. In particular, rotating the heavy gas turbine rotor 91 with high precision during maintenance and assembly can be a significant burden on workers. The above configuration makes it possible to significantly reduce this burden.

[0032] Furthermore, according to the above configuration, the circumferential positions of the multiple mounting portions 71 are within a range of ±45° from the horizontal direction. According to the above configuration, even if the gas turbine rotor 91 is displaced upward due to the effects of heat, the possibility of large fluctuations occurring in the gap between the tachometer 40 and the protrusion 53 due to such displacement can be reduced. More specifically, since the tachometer 40 is positioned in a radially extending position, the larger the vertical component included in the direction of this positioning, the more susceptible it becomes to the effects of upward displacement of the gas turbine rotor 91. According to the above configuration, since the tachometer 40 is positioned within a range of ±45° from the horizontal direction so as to reduce the vertical component, the possibility of being affected by such displacement can be reduced.

[0033] Furthermore, in the above configuration, there are three or more mounting parts 71 and tachometers 40. With this configuration, for example, compared to a case where only two or fewer tachometers 40 are provided, the rotational speed can be measured with higher precision by the tachometers 40. Also, even if one tachometer 40 malfunctions or fails and measurement becomes impossible, the remaining tachometers 40 can continue to measure the rotational speed. In other words, the availability of rotational speed measurement can be improved.

[0034] In addition, the mounting portion 71 is provided in two or more of the four circumferential regions formed by a first virtual line L1 extending horizontally through the axis O, and a second virtual line L2 passing through the axis O and perpendicular to the first virtual line L1. With the above configuration, the circumferential positions of the mounting portion 71 are dispersed. As a result, even if a disturbance such as a sudden rise in ambient temperature or collision with an obstacle occurs in one circumferential region and the tachometer 40 becomes immobile, the tachometer 40 provided in the mounting portion 71 of the other circumferential regions can continue to measure the rotational speed smoothly and stably.

[0035] Furthermore, each tachometer 40 is independently provided for each mounting portion 71, and each mounting portion 71 is an insertion hole 72 that penetrates the rotor cover 70 radially. With this configuration, since the tachometer 40 is inserted into the insertion hole 72 which serves as the mounting portion 71, it is possible to hold the tachometer 40 in a stable and rigid state inside the insertion hole 72. In other words, the possibility of the tachometer 40's posture or position being unintentionally shifted is reduced, and it becomes possible to continue measuring the rotational speed stably and accurately. Moreover, since multiple tachometers 40 are independent for each mounting portion 71, even if one tachometer 40 fails or malfunctions, the remaining tachometers 40 are not affected. This further improves the availability mentioned above.

[0036] Furthermore, the above-described gas turbine assembly method includes the steps of: step S1 attaching a tachometer 40 to each of the multiple mounting parts 71; step S2 aligning the phase of each tachometer 40 with each protrusion 53 by rotating the gas turbine rotor 91 around the axis O; and step S3 adjusting the distance between each tachometer 40 and each protrusion 53.

[0037] According to the above method, since the circumferential phase difference of the multiple mounting portions 71 is an integer multiple of the phase difference of two adjacent protrusions 53, if the circumferential position of any one tachometer 40 and one protrusion 53 coincides, the circumferential positions of the remaining tachometers 40 and their corresponding protrusions 53 will also coincide. As a result, when adjusting the gap of the tachometer 40, it is no longer necessary to rotate the rotor each time, and the rotor only needs to be rotated once, which significantly improves work efficiency compared to conventional methods.

[0038] (Other embodiments) Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure. In the above embodiment, an example was described in which the recess 52 and the protrusion 53 each have a rectangular cross-sectional shape. However, as long as the rotational speed can be measured by the tachometer 40, the shapes of the recess 52 and the protrusion 53 are not limited to the above. As a modified example, as shown in Figure 5, it is also possible to adopt a configuration in which the recess 52 and the protrusion 53 have a triangular cross-sectional shape. Even with such a configuration, the same effects and advantages as those described above can be obtained.

[0039] <Note> The gas turbine and gas turbine assembly method described in each embodiment can be understood, for example, as follows.

[0040] (1) The gas turbine 1 according to the first embodiment includes a rotor (gas turbine rotor 91) that is rotatable around an axis O and capable of transmitting power to a generator 60, a plurality of tachometers 40 that can independently measure the rotational speed of the rotor, and a rotor cover 70 that covers at least a part of the rotor from the outer circumference and has a plurality of mounting parts 71 to which the plurality of tachometers 40 can be mounted so that they face the axis, wherein recesses 52 and protrusions 53 used for measuring the rotational speed are alternately provided on the outer surface of the rotor in the circumferential direction, and the circumferential phase difference of the plurality of mounting parts 71 is an integer multiple of the phase difference of two adjacent protrusions 53 on the rotor.

[0041] According to the above configuration, the circumferential phase difference of the multiple mounting portions 71 is an integer multiple of the phase difference between two adjacent protrusions 53. Therefore, if the circumferential position of any one tachometer 40 and one protrusion 53 coincides, the circumferential positions of the remaining tachometers 40 and their corresponding protrusions 53 also coincide. This eliminates the need to rotate the rotor each time the gap of the tachometer 40 is adjusted, thereby improving work efficiency.

[0042] (2) The gas turbine 1 according to the second embodiment is the gas turbine 1 of (1), wherein the circumferential positions of the plurality of mounting portions 71 are within a range of ±45° with respect to the horizontal direction.

[0043] According to the above configuration, even if the rotor is displaced upward due to the effects of heat, the possibility of a large fluctuation occurring in the gap between the tachometer 40 and the protrusion 53 due to said displacement can be reduced.

[0044] (3) The gas turbine 1 according to the third embodiment is the gas turbine 1 of (1) or (2), wherein the number of the plurality of mounting parts 71 is three or more.

[0045] With the above configuration, for example, the rotational speed can be measured by the tachometer 40 with higher accuracy compared to the case where only two or fewer tachometers 40 are provided.

[0046] (4) The gas turbine 1 according to the fourth embodiment is a gas turbine 1 according to any one embodiment of (1) to (3), wherein one or more mounting portions 71 are provided in all of the four circumferential regions formed by a first virtual line L1 extending horizontally through the axis and a second virtual line L2 passing through the axis O and perpendicular to the first virtual line L1.

[0047] According to the above configuration, one or more mounting portions 71 are provided in each of the four circumferential regions formed by the first virtual line L1 and the second virtual line L2. In other words, the circumferential positions of the mounting portions 71 are dispersed. As a result, even if a disturbance occurs in one circumferential region, for example, the tachometer 40 provided on the mounting portions 71 in the other circumferential regions can continue to measure the rotational speed smoothly and stably.

[0048] (5) The gas turbine 1 according to the fifth embodiment is a gas turbine 1 according to any one embodiment of (1) to (4), wherein the tachometer 40 is provided independently for each mounting portion 71, and the mounting portion 71 is an insertion hole 72 that penetrates the rotor cover 70 in the radial direction.

[0049] With the above configuration, since the tachometer 40 is inserted into the insertion hole 72 which serves as the mounting portion 71, it is possible to hold the tachometer 40 in a stable and rigid state inside the insertion hole 72.

[0050] (6) A method for assembling a gas turbine 1 according to a sixth embodiment is a method for assembling a gas turbine 1 according to any one embodiment of (1) to (5), comprising: step S1 attaching the tachometer 40 to each of the plurality of mounting parts 71; step S2 aligning the phase of each tachometer 40 with each of the protrusions 53 by rotating the rotor around the axis; and step S3 adjusting the distance between each tachometer 40 and each of the protrusions 53.

[0051] According to the above method, since the circumferential phase difference of the multiple mounting portions 71 is an integer multiple of the phase difference of two adjacent protrusions 53, if the circumferential position of any one tachometer 40 and one protrusion 53 coincides, the circumferential positions of the remaining tachometers 40 and their corresponding protrusions 53 will also coincide. As a result, when adjusting the gap of the tachometer 40, it is no longer necessary to rotate the rotor each time, and the rotor only needs to be rotated once, thereby improving work efficiency. [Explanation of symbols]

[0052] 1…Gas turbine 10... Compressor 11… Compressor rotor 12… Compressor blade row 13… Compressor casing 14… Compressor stator blade row 15… Compressor blades 16… Compressor stator vanes 20... Combustor 21…Intermediate casing 30... Turbine 31... Turbine rotor 32... Turbine blade row 33... Turbine casing 34... Turbine stator blade row 35... Turbine blades 36... Turbine stator blades 40... Tachometer 50…Coupling 51…First flange 52…recess 53…Convex part 60... Generator 61…Generator rotor 62...Second flange 70... Rotor cover 71…Mounting part 72…Insertion hole 91... Gas turbine rotor (rotor) 92... Gas turbine casing O…Axis line

Claims

1. A rotor that is rotatable around its axis and capable of transmitting power to a generator, Multiple tachometers capable of independently measuring the rotational speed of each rotor, The rotor has a rotor cover that covers at least a portion of the rotor from the outer circumference and has a plurality of mounting parts to which the plurality of tachometers can be mounted so that they face the axis, The outer circumferential surface of the rotor is alternately provided with recesses and protrusions in the circumferential direction, which are used for measuring the rotational speed. The circumferential phase difference of the plurality of mounting portions is an integer multiple of the phase difference of two adjacent protrusions on the rotor. The gas turbine in which the circumferential positions of the plurality of mounting parts are within a range of ±45° with respect to the horizontal direction.

2. The gas turbine according to claim 1, wherein the number of the plurality of mounting parts is three or more.

3. The gas turbine according to claim 1 or 2, wherein the mounting portion is provided in two or more of four circumferential regions formed by a first virtual line extending horizontally through the axis and a second virtual line passing through the axis and perpendicular to the first virtual line.

4. The gas turbine according to claim 1 or 2, wherein the tachometer is provided independently for each mounting portion, and the mounting portion is an insertion hole that penetrates the rotor cover radially.

5. A method for assembling a gas turbine according to claim 1 or 2, The steps include attaching the tachometer to each of the aforementioned mounting parts, The steps include rotating the rotor around the axis to align the phases of each tachometer and each convex portion, The steps include adjusting the distance between each of the tachometers and each of the protrusions, A method for assembling a gas turbine, including [specific components / features].

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