JPH08218809A - Measuring method for steam turbine and its assembling - Google Patents

Abstract

PURPOSE: To facilitate assembling after confirmation of positional relation in respect to a rotor by providing a measuring seat near an upper half of a nozzle diaphragm of an upper half of the divided and lower halves of the nozzle diaphragm, and a measuring device arranged on the measuring seat. CONSTITUTION: A measuring seat 3 is arranged on a center of a double-current nozzle, while an upper surface 6 of the seat 3 is accurately mechanically processed. Positional relation in respect to a rotor 2 is accurately confirmed with the surface being reference. Length from the center to the upper surface of the seat 3 is represented by A, while a processing radius of the rotor 2 is represented by B. Length C from the upper surface 6 of the seat 3 to the rotor 2 is obtained by the euqation C=(A-B). This indicates the positional relation. The positional relation between the nozzle 1 and the rotor 2 is thus determined. The measuring seat 3 is arranged on an upper half of the nozzle, so that the positional relation between the nozzle and the rotor after assembling is measured by a measuring device. A steam turbine of high reliability can be assembled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine measuring method and an assembling method thereof.

[0002]

2. Description of the Related Art Generally, a nozzle diaphragm (hereinafter referred to as a nozzle), which is a stationary portion of a steam turbine, is installed so that a positional relationship with a rotor, which is a rotating body, is a designed clearance. This is an important control item in order to prevent leakage between the rotor and the nozzle, which affects performance, and contact during operation. In particular, the radial gap is as small as around 1 mm, which has a large effect on performance and operation, but changes during operation of the bearing portion supporting the rotor, movement of the rotor itself during rotation, or casing supporting the nozzle. Is determined in advance by predicting the structural or thermal change of the.

However, when considering the changes of the individual parts constituting the steam turbine in a combined manner, the change in the vertical direction is larger than the change in the horizontal direction, and these changes are considered only in the vertical direction. Is normal. In any case, when installing and assembling the steam turbine, where to bring the nozzle position with respect to the rotor position,
It is important to measure the gap accurately.

Here, the installation and assembly flow of the steam turbine of FIG. 7 will be described. First, the lower half of the outer casing is installed, and then the lower half of the inner casing is installed.
The nozzle has a circular structure, but is divided into two parts in the upper and lower halves in the horizontal part. Then, the lower half of the nozzle is first installed in the casing. At this time, a virtual piano wire of the rotor is stretched around the center of the rotor, and the position of the lower half of the nozzle is determined by checking the position of the piano wire. Furthermore, the position is determined in consideration of the change of each part predicted in advance. Recently, laser beams are sometimes used instead of piano wires. When the nozzle position is confirmed, install the rotor and check the gap between the nozzle and the nozzle.

By the way, the gap between the left and right horizontal portions of the gap between the nozzle and the rotor is accurate because it is directly measured by a gap gauge or the like, and the deformation of each component is small in the left-right direction. Especially, it is important to manage the changes in the vertical direction. Next, the lower part of the vertical gap is based on the following method. That is, the lead wire is placed in advance in the portion where the gap of the nozzle is to be measured, and when the rotor is installed, the lead wire is crushed leaving the gap portion. Remove the rotor once, take out the lead wire, and measure the part in charge of the gap with a caliper or the like. In this way, the gap between the nozzle and the rotor is measured, and the rotor is installed in such a gap.

After this, the upper half of the nozzle is assembled and the rotor is hidden by the nozzle. The assembly of the inner casing and the outer casing of the upper half continues, and the nozzle is included. In this state, there is no method for measuring the positional relationship between the nozzle and the rotor in the radial direction except for a part of the last flow.

Since the position of the nozzle is determined by predicting the change of each component as described above, there is a possibility that the rotating part and the stationary part may come into contact with each other if the prediction is significantly different from the actual one. The rotor may vibrate and the turbine may not operate.

[0008]

As described above, in the prior art, after the upper half of the nozzle is assembled, there are only a limited number of places for checking the positional relationship between the nozzle and the rotor. I couldn't figure it out.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for measuring a steam turbine that enables reliable assembly by checking the positional relationship with the rotor even after the upper half nozzle is assembled. It is to provide the assembling method.

[0010]

In order to achieve the above object, the first aspect of the present invention provides a steam turbine rotor, and a bearing provided on a casing or a bearing stand that supports a shaft portion of the front and rear portions of the rotor. A nozzle diaphragm that is arranged at a predetermined interval from the rotor and is a combination of two upper and lower halves; a measurement seat provided near the center of the upper part of the upper half nozzle diaphragm; and a measurement seat. And a relative position between the rotor, which is a rotating body, and the nozzle diaphragm, which is a stationary portion, is measured by the measuring device.

According to a second aspect of the present invention, in the steam turbine measuring method according to the first aspect, a mechanical measuring device is arranged on the measuring seat to form the rotor as a rotor and the nozzle diaphragm as a stationary part. It is characterized by measuring the relative position with the dial gauge.

According to a third aspect of the present invention, in the method for measuring a steam turbine according to the first aspect, an electric measuring device is arranged on the measuring seat and the rotor that is a rotating body and the nozzle diaphragm that is a stationary portion. It is characterized in that the relative position with respect to is measured by an electric signal.

According to a fourth aspect of the present invention, the data measured by the steam turbine measuring method according to the first aspect is compared with the design value of the clearance between the rotor and the nozzle diaphragm, and the difference is an allowable value. The steam turbine is assembled by changing the thickness of the adjusting shim for supporting the inner casing incorporating the nozzle diaphragm so that

[0014]

Since the steam turbine rotor is a heavy object, it bends around the bearing portion as a fulcrum, and the maximum deflection occurs near the center thereof. The displacement generated in the bearing portion is slightly different in the central portion away from the bearing. According to the present invention, a seat for measurement is provided in the upper half of the nozzle to grasp the positional relationship between the nozzle and the rotor near the center of the rotor,
As a result, since the positional relationship between the nozzle and the rotor after assembly can be measured, a highly reliable steam turbine can be assembled.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a configuration diagram of an embodiment of the present invention (corresponding to claim 1 and claim 2), and FIG. 2 is a sectional view in the axial direction of FIG. As shown in these figures, the low pressure part of a normal steam turbine is
Since the specific volume of steam increases due to expansion in the high-pressure and intermediate-pressure parts, the double-flow type nozzle 1 in which the inflowing steam flows both in the front and back is used. Since there is a space in the central portion of this double-flow type nozzle, the seat 3 for measurement is provided in this portion. The seat 3 is also provided with a through hole 4 and a screw 5 is screwed in to allow the plug to be screwed in to prevent steam from flowing through this hole after the measurement is complete. The upper surface 6 of the seat 3 is accurately machined, and with this surface as a reference plane, the rotor 2
It is possible to check the positional relationship between and. It is easy to preliminarily attach the seat 3 by welding or the like at the time of manufacturing the nozzle, and the processing is not difficult. Zodiac 3
Are provided in the upper half of the nozzle 1 for ease of measurement and access. Further, since the change in the vertical direction is large, a seat is provided in the vicinity directly above because it is necessary to manage the gap in this direction.

However, the distance from the center to the upper surface 6 of the seat 3 is accurately machined, and if the distance is A and the processing radius of the rotor 2 is B, the upper surface 6 of the seat 3 to the rotor 2 will be described. The distance C to is obtained by C = (AB), which indicates the positional relationship on the drawing. The design value of the positional relationship between the nozzle 1 and the rotor 2 is determined in consideration of the deformation of each component and the thermal change during operation.

In the mechanical measuring device 10, as shown in FIG. 3B, the rod 11 and the dial gauge 12 are the main components, and the probe 13 of the dial gauge is kept fully extended. From the tip of the rod 11 to this probe 13
The distance D up to is measured in advance. Since the rod 11 can be changed according to the distance between the rotor 2 and the nozzle 1, various lengths can be accommodated.

FIG. 3A is a diagram for explaining a method of measuring the distance between the rotor and the nozzle using the measuring device 10. That is, the rod 11 of the measuring device 10 is inserted into the hole 4 of the seat 3 provided at substantially the center of the nozzle 1. At this time, if the gap between the rod 11 and the hole 4 is large, the rod 11
Since there is a risk that the rotor will be tilted and the distance between the rotor and nozzle cannot be measured accurately and stably, the diameters of the rod and hole are set so that there is relatively no gap. And rod 11
The measuring device 10 is put in until the tip of the touches the rotor 2, and the value θ shown on the dial gauge 12 is obtained. This value θ and the distance from the tip of the rod 11 measured in advance to the probe 13 are added to measure the distance from the upper surface of the measurement seat to the rotor. Thereby, the positional relationship between the rotor and the nozzle, that is, the gap can be compared with the designed value. This measurement can be performed by a person using the manhole provided in the casing even after the upper half casing is assembled.

FIG. 4 is a block diagram of another embodiment (corresponding to claim 3) of the present invention. As shown in the figure, since there is a space in the central portion of this type of nozzle 21, a measurement seat 23 is provided in this portion. Further, the seat 23 is provided with a through hole 24, and the screw 25 is cut so that the plug can be screwed in to prevent vapor from flowing through the hole 24 after the measurement is completed. . Zodiac 23
The upper surface 26 of is accurately machined, and the positional relationship with the rotor 22 can be accurately confirmed by using this surface 26 as a reference plane. The seat 23 is provided in the upper half of the nozzle 21 for ease of measurement and access. Further, since the change in the vertical direction is large, a seat is provided in the vicinity directly above because it is necessary to manage the gap in this direction.

At the time of measurement between the rotor and the nozzle, the electrical measuring device 28 is attached to the seat 23 by the attachment 27. An electric gap measuring probe 29 is attached to the tip of a measuring device 28 attached to the upper surface of the seat 23, and a distance E from the attachment surface of the seat to the tip of the probe 29.
Is measured in advance. The probe 29 measures the distance F from its tip to the rotor 22 and outputs it as an electric signal to the outside. Thus, the distance from the mounting surface of the seat 23 to the rotor 22 is obtained. In this electrical measurement,
There is no need for a person to enter the inside during measurement, and continuous measurement is possible. The cable can be protected by passing it inside the pipe.

FIG. 5 is a flow chart of another embodiment of the present invention (corresponding to claim 4), that is, a steam turbine is assembled using the values measured by the measuring device. First, the lower half of the outer casing is installed, and then the lower half of the inner casing is installed. The lower half of the nozzle is first installed in the casing, and the rotor is installed so that the gap between the nozzle and the rotor has a predetermined value. The upper half nozzles are assembled and the upper half inner casing is installed before rotor position is measured. This measured value is compared with the design value.
Since the measurement is performed in the upper half, when the value is smaller than the design value, it means that the nozzle is going down to the rotor, and when it is larger than the designed value, it is going up. If this amount is within the allowable range, it has been confirmed that the assembled state is good. If it is out of tolerance, the entire inner casing incorporating the nozzle needs to be adjusted.

Further, as shown in FIG. 6, the inner casing 7 is supported by the outer casing 8 at four locations through shims 9 for adjustment. By changing the thickness of the shims 9, the inner casing 7 is changed. 7. Consequently, the position of the nozzle can also be changed in the vertical direction. In order to adjust the shim 9, the internal sequence 7 is slightly lifted by using a jack or the like, and the shim 9 which has been adjusted is inserted into the internal sequence 7. Obtain this adjustment amount from the measured value and design value,
The thickness of the shim 9 can be determined. In this way,
The positional relationship between the designed nozzle and the rotor can be obtained.

[0023]

As described above, according to the present invention,
It is possible to know the positional relationship between the nozzle and rotor after the upper half assembly of a steam turbine, which could not be known by conventional technology.By this, the difference from the design value can be grasped and reflected in assembly, and highly reliable steam can be obtained. A turbine can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is a diagram for explaining measurement by a mechanical measuring device according to the present invention.

FIG. 4 is a diagram for explaining measurement by the electrical measuring device according to the present invention.

FIG. 5 is a flowchart of a method for assembling a steam turbine according to the present invention.

FIG. 6 is a view in which a shim is provided between the inner and outer casings.

FIG. 7 is a flowchart of a conventional method for assembling a steam turbine.

[Explanation of symbols]

1, 21 ... Nozzle, 2, 22 ... Rotor, 3, 23 ... Seat,
4, 24 ... hole, 5, 25 ... screw, 6, 26 ... upper surface of seat,
7 ... inner casing, 8 ... outer casing, 9 ... shim,
10 ... Mechanical measuring device, 11 ... Rod, 12 ... Dial gauge, 13 ... Probe, 27 ... Fixture, 28 ... Electrical measuring device, 29 ... Probe.

Claims (4)

[Claims] 1. A combination of a steam turbine rotor, a bearing provided in a casing or a bearing stand for supporting a shaft portion of a front and rear portion of the rotor, and a rotor divided into two parts, which are arranged at a predetermined interval and are divided into two upper and lower halves. A nozzle diaphragm, a measuring seat provided near the center of the upper part of the upper half nozzle diaphragm, and a measuring device arranged on the measuring seat, and the rotor, which is a rotating body, is stationary by the measuring device. A method for measuring a steam turbine, comprising: measuring a relative position with respect to the nozzle diaphragm which is a part. 2. A steam turbine measuring method according to claim 1, wherein a mechanical measuring device is arranged on said measuring seat to dial a relative position between said rotor which is a rotating body and said nozzle diaphragm which is a stationary portion. A method for measuring a steam turbine, which is characterized by measuring with a gauge. 3. The method for measuring a steam turbine according to claim 1, wherein an electric measuring device is arranged on the measuring seat, and a relative position between the rotor, which is a rotating body, and the nozzle diaphragm, which is a stationary portion, is electrically measured. A method for measuring a steam turbine, which is characterized by measuring with a signal. 4. The data measured by the steam turbine measuring method according to claim 1 is compared with a design value of a clearance between the rotor and the nozzle diaphragm, and the nozzle is adjusted so that the difference becomes an allowable value. A method for assembling a steam turbine, wherein the thickness of an adjusting shim that supports an inner casing incorporating a diaphragm is changed to assemble the steam turbine.