JPH0367002A - Assembly of steam turbine - Google Patents

Abstract

PURPOSE:To appropriately set a gap between a static part and a rotary part on the side of a turbine rotor, which is required at the time of completion of assembly, at the time of measuring clearance by temporarily assembling a turbine casing and correctly finding a displacement value of the static part at the time of the clearance measurement and the time of the completion of the temporary assembly. CONSTITUTION:The lower half part of a static part 2 such as a blade ring 2a or a dummy ring 2b is detached to the lower half part la of a turbine casing, and a mandrel 4 is mounted on the position of the turbine casing to detach a rotor. And an arm 5 is set on the position of the mandrel 4 to cope with the static part 2. Subsequently, the distance from the shaft center of the mandrel 4 to the static part 2 is measured with a displacement gauge 6 and the result is regarded as G1, and the upper half of the static part 2 is detached on the lower half part la and then the upper half part 1b is detached to complete the temporary assembly of the turbine. Then the distance from the shaft center of the mandrel 4 to the static part 2 is measured with the displacement gauge 6 and the result is regarded as G2. Thereafter, the difference between the distance G1 and the distance G2 is obtained and the result is regarded as a displacement value m of the static part 2 at the time of the measurement of clearance and the time of the completion of the temporary assembly. Thereafter, the mandrel 4 is removed, and a regular turbine rotor is detached to have the gap between the static pat and the rotary part at a planned clearance value plus (m).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention aims to minimize the gap between stationary parts such as blade rings and dummy rings provided in the turbine casing and rotating parts attached to the turbine rotor. The present invention relates to a method of assembling a steam turbine that approaches a value close to that value.

Conventional technology In steam turbines, setting the gap (this is called play) between the turbine rotor and stationary parts such as blade rings and dummy rings is extremely important to ensure performance and reliability. It has meaning. That is, if the play is too large, the amount of steam leaking will increase, leading to a decline in performance, while if the play is too small, the rotating parts will come into contact with the stationary parts, impairing reliability.

By the way, this play differs between a state in which the lower half of stationary parts such as a blade ring and a dummy ring are assembled to the lower half of the turbine casing, and a state in which the turbine is fully assembled with the turbine rotor assembled in a predetermined position. The adjustment and settings have been difficult because they differ. The reason for this difference in play is as follows.

In other words, during the turbine assembly process, when it is appropriate to adjust or measure the play, the lower half of the turbine casing is
When assembling the lower half of stationary parts such as blade rings or dummy rings (
This state is hereinafter referred to as the state at the time of play measurement), and in this state, the turbine casing has a semi-cylindrical shape, so its rigidity is not so strong.

On the other hand, when the turbine assembly is completed, the upper half of stationary parts such as the blade ring and the dummy ring are also assembled, and the upper half of the turbine casing is also attached, so the load due to its own weight increases. However, since the upper and lower single chambers of the turbine are tightened by flange bolts at the horizontal joint surface, the casing becomes cylindrical and has increased rigidity.

These situations are shown in FIGS. 3 to 5.

Figure 3 shows the state during play measurement, and the turbine casing has only the lower half 1a, so its rigidity is small, but stationary parts such as the blade ring 2a and gummy ring 2b are only assembled in the lower half. Due to its condition, it is light in weight.

Figure 4 shows the state in which the upper halves of the stationary parts 2a and 2b are also assembled.The rigidity of the turbine casing is similar to that in Figure 3 and is small, but the weight of the stationary parts increases because the upper halves are also added.
Therefore, the deflection increases compared to the state shown in FIG.

Figure 5 shows the state when the turbine casing is assembled with the upper half 1b also attached, and although the weight increases, the upper half 1b and lower half 1a of the turbine casing are tightened. Therefore, rigidity increases. Therefore, the deflection is smaller than in the case of only the lower half portion 1a.

In this way, between the time of play measurement and the time of turbine assembly completion,
The amount of deflection changes. On the other hand, since the deflection of the rotor is always the same, the play between the rotor and the stationary part will be different in each case. However, since the play cannot be adjusted when the turbine is assembled,
takes this difference into account when measuring the play and adjusts the play.

Therefore, as shown in FIGS. 6 and 7, the dial indicator 3 is attached to the lowest part of the lower half 1a of the turbine casing, and the indicated value of the dial indicator 3 (
Read the indicated value (displacement) M+ and the indicated value (displacement) L of the dial indicator 3 when the turbine assembly is completed, and find the difference (M, -M,)
is the vertical displacement m of the stationary parts 2 (2a, 2b), and the play value that must be secured at the time of completion of turbine assembly is δI (i.e., design value), and the play value set at the time of play measurement is When δ, the size of the gap at the time of play measurement is set so that δt0 δ, +, ◆-(1). This conventional method is called the bottom reading method.

Problems to be Solved by the Invention By the way, the above-mentioned bottom reading method regards the displacement of the lower half portion 1a of the turbine casing as the displacement of the stationary component 2, so it does not apply to all cases.
The problem was that it wasn't necessarily correct.

In other words, as shown in Figs. 8 and 9, the inclination of the horizontal joint surface in the direction perpendicular to the axis changes depending on when the upper and lower parts of the stationary part 2 are tightened together and when only the lower half is retracted. In such a case, the resulting displacement of the stationary component 2 cannot be determined by the bottom reading method. Although such a phenomenon can occur even when each part is new, it is particularly noticeable in a turbine that has been used several times because the parts are deformed.

The present invention therefore solves such problems and ensures that the desired gap between the rotating and stationary parts upon completion of assembly is
This was done with the purpose of providing a method for assembling a steam turbine that allows the flange adjustment to be made as close to the design value as possible during the assembly process.

Means for Solving the Problems The present invention provides a process for assembling the lower half of stationary parts such as a blade ring or a dummy ring into the lower half of the turbine casing to bring it into a state for so-called play measurement, and The installation of the turbine rotor includes a step of installing a mandrel equipped with a displacement measuring device at key points, and a step of measuring a distance G from the axis of the mandrel to the stationary component using the displacement measuring device.
A step of temporarily assembling the turbine by assembling the upper half of stationary parts such as the blade ring and dummy ring on the lower half of the turbine casing and then assembling the upper half of the turbine casing; The distance G from the mandrel axis to the stationary part is measured by the displacement measuring device! and the process of measuring these measured values G+
, a step of detecting the displacement position m (m=G+Gt) of the stationary component between the time of measuring the play and the time of completion of temporary assembly of the turbine from the difference in Gy, and the step of opening the upper half of the turbine casing and removing the mandrel. and a step of assembling a regular turbine rotor after removing the mandrel, and when assembling the turbine rotor, the gap δ between the stationary component and the rotating component on the turbine rotor side is adjusted to The design clearance value δ1 is adjusted to a value obtained by adding the displacement position m.

According to the above-mentioned means, by measuring the displacement of the stationary components at the time of measuring the play during the turbine assembly process and at the time of completion of temporary assembly of the turbine, the displacement of the stationary components between the two states can be determined. Since the clearance between the stationary component and the rotating component on the turbine side is set in consideration of this positional displacement when measuring the clearance, it is possible to bring the clearance value as close as possible to the desired value when the turbine is assembled.

EXAMPLE Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 shows an example of the process of assembling a steam turbine according to the present invention, and FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG.

First, as in the conventional case, a blade ring 2 is attached to the lower half 1a of the turbine casing.
Assemble the lower half of the stationary parts 2 such as a and the gummy ring 2b. Next, a mandrel 4 is installed in place of the rotor at the position where the turbine rotor is to be installed in the turbine casing. This mandrel 4 can be supported using a rotor support bearing. Arms 5 are attached to the mandrel 4 at necessary locations in the axial direction, that is, at positions corresponding to the stationary parts 2 such as the blade ring 2a and the gummy ring 2b. A remote-controlled displacement measuring device 6 is attached to the tip of the arm 5.

Although a non-contact type displacement measuring device 6 is shown in the figure, a contact type device such as a dial indicator may be used if possible depending on the situation. However, even in this case, it is necessary that remote control is possible. The reason for this is that measurement by the displacement measuring device 6 is required with the upper half of the turbine casing in an assembled state.

Therefore, first, the lower half of the stationary parts 2 such as the blade ring 2a and the gummy ring 2b are assembled to the lower half 1a of the turbine casing (
In other words, when the turbine rotor is installed (in the play measurement state), the distance from the axis of the mandrel 4 to the stationary component 2 is measured using the displacement measuring device 6 of the mandrel 4 set in position, and this is defined as G. do.

Next, the upper half of the stationary parts 2 such as the blade ring 2a and the gummy ring 2b are assembled onto the lower half la of the turbine casing, and then the upper half 1b of the turbine casing (see Fig. 5) is assembled. Attach it to complete the temporary assembly of the turbine. In this state, the distance from the axis of the mandrel 4 to the stationary component 2 is measured again using the displacement measuring device 6 of the mandrel 4, and this distance is defined as G.

The difference between these measured values G+ and Gt is determined and taken as the displacement ff1m of the stationary component 2 at the time of measuring the play and at the time of completion of temporary assembly. That is, m=G+Gy.

Thereafter, the upper half 1b of the turbine casing is opened, the mandrel 4 is removed, and after the mandrel 4 is removed, a regular turbine rotor is assembled. When assembling this regular turbine rotor, the gap between the stationary part 2 and the rotating part on the turbine rotor side is adjusted to the design clearance value at the time of assembly completion at the displacement position m.
Adjust the value so that it is the sum of .

In other words, the gap between the stationary part 2 and the rotating part of the Tahin rotor example during adjustment is δ7, and the design clearance value at the time of assembly completion is δ1.
, if the displacement of the stationary part 2 at the time of play measurement and at the time of completion of temporary assembly is m, then at the time of play measurement, the stationary part 2 and the turbine are adjusted so that δ, -δ, 10 m ・ ・ ・ (2) Reduce the gap between the rotor and the rotating parts.

Effects of the Invention As detailed above, according to the present invention, by temporarily assembling the turbine casing and accurately determining the displacement position of the stationary parts at the time of play measurement and at the time of completion of the temporary assembly, The required gap between the stationary component and the rotating component on the turbine rotor side can be appropriately set when measuring the play.

Therefore, according to the present invention, a method for assembling a steam turbine is provided that can improve the performance and reliability of the turbine.

[Brief explanation of drawings]

FIG. 1 is a partial side view of a turbine casing showing how displacement is measured by a mandrel in order to explain an embodiment of the method of assembling a steam turbine according to the present invention, and FIG. A sectional view taken along the line ■-■ in FIG. 1 shown for explanation, and FIGS. 3 to 5 are views of the turbine casing shown to explain the displacement of stationary parts during the assembly process of the steam turbine. 6 is a partial side view of the turbine casing shown to explain the conventional bottom reading method; FIG. 7 is a sectional view taken along the line ■-■ in FIG. 6; 8 and 9 are partial sectional views of the turbine casing shown for explaining the problems caused by the bottom reading method. la... lower half of the steam turbine casing, 1b... upper half,
2...Stationary parts, 2a...Blade ring, 2b...Dummy ring, 3
...Dial indicator, 4...Mandrel, 5...
Arm, 6...displacement measuring device.

Claims (1)

[Claims] The process involves assembling the lower half of stationary components such as blade rings and dummy rings into the lower half of the turbine casing to create a state for so-called play measurement, and displacing the turbine rotor at key locations in the turbine casing. A step of installing a mandrel equipped with a measuring device, a step of measuring the distance G_1 from the axis of the mandrel to the stationary component using the displacement measuring device, and a step of installing the blade ring or dummy on the lower half of the turbine casing. A process of temporarily assembling the turbine by assembling the upper half of stationary parts such as rings and then assembling the upper half of the turbine casing; The process of measuring the distance G_2 and these measured values G_1, G
A step of detecting the displacement position m (m=G_1-G_2) of the stationary parts between the time of measuring the play and the time of completion of temporary assembly of the turbine from the difference of _2, and opening the upper half of the turbine casing and removing the mandrel. The process consists of a removing process and a process of assembling a regular turbine rotor after removing the mandrel. When assembling the turbine rotor, the gap δ_2 between the stationary part and the rotating part on the turbine rotor side is adjusted to A method for assembling a steam turbine, characterized in that adjustment is made to a value obtained by adding the displacement position m to a design clearance value δ_1.