JP2017025820A - Nozzle diaphragm attaching structure of steam turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the floating of a diaphragm due to the application of bending moment on a support bar.SOLUTION: A nozzle diaphragm attaching structure 10 of a steam turbine has a casing 20, a nozzle diaphragm 30, and a support bar 40. An upper boundary face S1 and a lower boundary face S2 are formed between a recessed portion 35 of the nozzle diaphragm 30 and a projecting portion 45 of the support bar 40, and reamer pins 46, 47 are respectively provided on the upper boundary face S1 and the lower boundary face S2.SELECTED DRAWING: Figure 1

Description

  This embodiment relates to a nozzle diaphragm mounting structure for a steam turbine.

  The steam turbine has a casing, a rotor, a nozzle diaphragm provided in the casing, and a moving blade provided in the rotor. The nozzle diaphragm is attached to the casing by a support bar. In this case, the support bar of the nozzle diaphragm supports the weight of the nozzle diaphragm and has the function of adjusting the vertical shim position so that it does not contact the rotor by changing the thickness of the adjustment shim and adjustment liner provided on the casing side. ing. In addition, a spacer is installed on the upper surface of the support bar, and the spacer thickness is adjusted to sandwich the support bar between the lower half and the upper half of the casing. (For example, refer to Patent Documents 1 and 2).

  In a transient state such as when the turbine starts and stops, the temperature change of the turbine parts over time is large, and the relative displacement between the support bar and the casing is caused by the difference in thermal expansion between the nozzle diaphragm and the casing. The frictional resistance between the contact surface of the support bar and the casing increases due to deformation due to thermal expansion.

  At this time, since the relative displacement between the support bar and the casing is constrained, the support bar may be deformed and a gap may be formed between the nozzle diaphragm and the support bar (opening deformation). This opening deformation is an event caused by a bending moment acting on the support bar. When mouth opening deformation occurs, the lower half of the nozzle diaphragm rises, and the gap between the rotor, which is a rotating body, and the nozzle diaphragm, which is a stationary component, is narrowed, so that the labyrinth packing and the rotor that constitute the nozzle diaphragm There is a possibility of causing contact and inducing a roller rubbing vibration.

JP 2011-220332 A JP 2011-106452 A

  The present embodiment has been made in consideration of such points, and provides a nozzle diaphragm mounting structure for a steam turbine in which a bending moment acts on the support bar and the lower half of the nozzle diaphragm does not float. Objective.

In this embodiment, the nozzle diaphragm mounting structure of the steam turbine
A casing, a nozzle diaphragm provided in the casing, and a support bar interposed between the casing and the nozzle diaphragm;
The nozzle diaphragm has a recess extending in the horizontal direction, the support bar is fitted in the recess and has a projection extending in the horizontal direction,
The convex portion forms an upper interface and a lower interface with the concave portion, and a reamer pin extending in the horizontal direction along the upper interface or the lower interface is provided on either the upper interface or the lower interface. It is the nozzle diaphragm attachment structure of a steam turbine.

In this embodiment, the nozzle diaphragm mounting structure of the steam turbine
A casing, a nozzle diaphragm provided in the casing, and a support bar interposed between the casing and the nozzle diaphragm;
The nozzle diaphragm has a recess extending in the horizontal direction, the support bar is fitted in the recess and has a projection extending in the horizontal direction,
One of the nozzle diaphragm and the support bar is provided with a vertical groove, and the other is provided with a vertical protrusion that engages with the vertical groove.
A steam diaphragm nozzle diaphragm mounting structure comprising a reamer pin extending in a horizontal direction through the vertical groove and the vertical protrusion.

In this embodiment, the nozzle diaphragm mounting structure of the steam turbine
A casing, a nozzle diaphragm provided in the casing, and a support bar interposed between the casing and the nozzle diaphragm;
The nozzle diaphragm has a recess extending in the horizontal direction, the support bar is fitted in the recess and has a projection extending in the horizontal direction,
Either one of the nozzle diaphragm and the support bar is provided with a vertical groove, and the other is provided with a vertical protrusion that engages with the vertical groove and forms a groove structure with the vertical groove.
A nozzle diaphragm mounting structure for a steam turbine, wherein a space for a support bar entry is provided below the support bar in the nozzle diaphragm.

  According to the present embodiment, no bending moment is applied to the support bar, and therefore the lower half of the nozzle diaphragm is not lifted.

FIG. 1 is a side sectional view showing a first embodiment of a nozzle diaphragm mounting structure of a steam turbine. FIG. 2 is a perspective view showing a mounting structure of a nozzle diaphragm and a support bar. FIG. 3 is an enlarged side view showing the steam turbine. FIG. 4 is a cross-sectional view showing a steam turbine. FIGS. 5A and 5B are views showing a second embodiment of a nozzle diaphragm mounting structure of a steam turbine. FIGS. 6A and 6B are views showing a third embodiment of a nozzle diaphragm mounting structure of a steam turbine. Fig.7 (a) is a perspective view which shows the comparative example of the nozzle diaphragm attachment structure of a steam turbine, FIG.7 (b) is the sectional side view. FIG. 8 is an operation diagram showing a comparative example of a nozzle diaphragm mounting structure of a steam turbine.

DETAILED DESCRIPTION OF THE INVENTION

<First Embodiment>
Hereinafter, an embodiment of a nozzle diaphragm mounting structure of a steam turbine will be described with reference to the drawings.

FIG. 1 to FIG. 4 are views showing a first embodiment of a nozzle diaphragm mounting structure of a steam turbine.
First, the structure of the steam turbine 1 will be described with reference to FIGS.

  As shown in FIGS. 3 and 4, the steam turbine 1 includes a casing 20 having a lower half 20 </ b> A and an upper half 20 </ b> B, a rotor 2 disposed in the casing 20, and a moving blade attached to the rotor 2. 3 and a nozzle diaphragm 30 provided in the casing 20 and having a lower half 30A and an upper half 30B.

  3 and 4, the lower half 20A of the casing 20 is shown. The nozzle diaphragm 30 includes an outer ring 31, an inner ring 32, and a stationary blade 33 interposed between the outer ring 31 and the inner ring 32.

  The nozzle diaphragm 30 having such a configuration is attached to the casing 20 via a support bar 40.

Next, the mounting structure of the nozzle diaphragm 30 will be described with reference to FIGS.
In FIG. 1, the “z” axis represents the vertical direction (or radial direction), “x” represents the horizontal direction (or radial direction), and the “A” axis represents the axial direction of the rotor 2. As shown in FIG. 1, a turbine diaphragm mounting structure 10 includes a steam turbine casing 20 having a lower half 20A and an upper half 20B, and a lower half 30A and an upper half 30B provided in the casing 20. Afram 30 is provided.

  A support bar 40 that holds the nozzle diaphragm 30 is provided between the casing 20 and the nozzle diaphragm 30. Of these, the lower half portion 30A of the nozzle diaphragm 30 has a concave portion 35 extending in the horizontal direction, and the support bar 40 is fitted into the concave portion 35 of the lower half portion 30A of the nozzle diaphragm 30 and the convex portion 45 extending in the horizontal direction. Have

  As shown in FIG. 1, the convex portion 45 and the concave portion 35 form an upper interface S1 and a lower interface S2 above and below each other.

  Furthermore, the convex part 45 and the concave part 35 are in contact with each other on the back side to form a back side interface S3.

  Further, as shown in FIG. 1, a reamer bin 46 extending between the convex portion 45 and the concave portion 35 along the upper interface S1 and the lower interface S2 in parallel with the upper interface S1 and the lower interface S2 and in the A-axis direction. , 47 are provided.

  Of the reamer pins 46 and 47 provided on the upper interface S1 and the lower interface S2, for example, the reamer pin 46 may be provided only on the upper interface S1 without providing the reamer pin 47 on the lower interface S2. Or conversely, the reamer pin 47 may be provided only in the lower interface S2 without providing the reamer pin 46 in the upper interface S1.

  The support bar 40 is connected to the lower half 20A and the upper half 20B of the casing 20 via an adjustment shim 48 provided on the lower surface of the support bar 40 and a space 49 provided on the upper surface of the support bar 40. It is clamped between and fixed.

  By the way, the upper interface S1 and the lower interface S2 formed between the lower half 30A of the nozzle diaphragm 30 and the support bar 30 each have a gap of 0 to 0.1 mm.

  Moreover, since the convex part 45 and the recessed part 35 are mutually contact | abutting, the gap | interval is 0 mm in back side interface S3.

  As described above, the back side interface S3 is formed between the concave portion 35 of the lower half 30A of the nozzle diaphragm 30 and the convex portion 45 of the support bar 40. Above the back side interface S3, A gap G1 formed between the convex portion 45 and the concave portion 35 is formed.

  A gap G2 of 0.15 to 0.30 mm is formed between the spacer 49 provided on the upper surface of the support bar 40 and the upper half portion 20B of the casing 20.

  Furthermore, the adjustment shim 48 provided on the lower surface of the support bar 40 and the spacer provided on the upper surface of the support bar 40 are both made of a carbon sliding body. For this reason, when the temperature change of the turbine components with time increases when the turbine is started and stopped, the support bar 40 remains in the lower half portion 20A of the casing 20 even if the thermal expansion difference between the nozzle diaphragm 30 and the casing 20 occurs. And it can slide easily with respect to the upper half part 20B.

  In FIG. 1, reference numeral 50 denotes a horizontal joint surface that defines between the lower half 20A and the upper half 20B of the casing 20 and between the lower half 30A and the upper half 30B of the nozzle diaphragm 30. ing.

Next, the operation of the present embodiment having such a configuration will be described.
As shown in FIGS. 1 and 2, the temperature change of the turbine components with time increases when the turbine starts and stops. In this case, a thermal expansion difference is generated between the nozzle diaphragm 30 and the casing 20, and a relative displacement is generated between the support bar 40 and the casing 20.

  In addition, the nozzle diaphragm 30 and the casing 20 may be deformed by thermal expansion, and the support bar 40 may be strongly sandwiched between the lower half 20A and the upper half 20B of the casing 20.

  According to the present embodiment, the reamer pins 46 and 47 are interposed in the upper interface S1 and the lower interface S2 between the convex portion 45 and the concave portion 35, respectively. For this reason, a relative displacement occurs between the support bar 40 and the casing 20, and even if the lower half 20A of the casing 20 moves to the right in FIG. The diaphragm 30 is securely fixed to the lower half 30A side.

  For this reason, when the lower half portion 20A of the casing 20 moves to the right in FIG. 2, no bending moment is applied to the support bar 40 clockwise with the point A as a fulcrum, and the support bar 40 supports the point A as a fulcrum. As a result, the support bar 40 is lifted and the nozzle diaphragm 30 is not moved upward.

  Next, a comparative example of the nozzle diaphragm mounting structure of the steam turbine will be described with reference to FIGS.

  In the comparative examples shown in FIGS. 7A and 7B and FIG. 8, the same parts as those in the first embodiment shown in FIGS.

  As shown in FIG. 7A and FIG. 8, the nozzle diaphragm mounting structure 10 of the steam turbine is provided in the casing 20 having a lower half 20A and an upper half 20B, and the lower half 30A. And a nozzle diaphragm 30 having an upper half 30B.

  Further, a support bar 40 that holds the nozzle diaphragm is provided between the casing 20 and the nozzle diaphragm 30. Of these, the lower half 30A of the nozzle diaphragm 30 has a recess 35 extending in the horizontal direction, and the support bar 40 is fitted into the recess 35 of the lower half 30A of the nozzle diaphragm 30 and has a protrusion 45 extending in the horizontal direction. Have.

  Moreover, as shown in FIG. 8, the convex part 45 and the recessed part 35 form the upper interface S1 and the lower interface S2 above and below.

  The support bar 40 is connected to the lower half 20A and the upper half 20B of the casing 20 via an adjustment shim 48 provided on the lower surface of the support bar 40 and a spacer 49 provided on the upper surface of the support bar 40. It is clamped between and fixed.

  In FIG. 8, reference numeral 50 denotes a horizontal joint surface that defines between the lower half 20A and the upper half 20B of the casing 20 and between the lower half 30A and the upper half 30B of the nozzle diaphragm 30. ing.

  Further, as shown in FIGS. 7A, 7B and 8, the adjustment shim 48 is attached to the lower half portion 20A of the casing 20 by the attachment bolt 48a, and the spacer 47 is attached to the support bar 40 by the attachment bolt 47a. ing.

  Further, the support bar 40 is attached to the lower half 30A of the nozzle diaphragm 30 by means of mounting bolts 40a.

  In the comparative example shown in FIGS. 7A and 7B and FIG. 8, when the temperature change of the turbine components with time increases when the turbine starts and stops, a difference in thermal expansion occurs between the nozzle diaphragm 30 and the casing 20, and the support bar. A relative displacement may occur between 40 and the casing 20. In this case, the nozzle diaphragm 30 and the casing 20 are deformed by thermal expansion, and the support bar 40 is strongly sandwiched between the lower half 20A and the upper half 20B of the casing 20.

  At this time, when the lower half portion 20A of the casing 20 moves to the right in FIG. 8, for example, the support bar 40 rotates clockwise with a bending moment about the point A as a fulcrum, and the support bar 40 and the nozzle diaphragm 30 A gap G3 is formed between the half 30A. As described above, when the support bar 40 rotates clockwise with the point A as a fulcrum, the support bar 40 is lifted.

  In this case, the dimensions of the gap G4 between the rotor blade 3 and the outer ring 31 of the nozzle diaphragm 30 and the gap G5 between the rotor 2 and the inner ring 32 change. (See FIGS. 3 and 4).

  On the other hand, according to the present embodiment, the reamer pins 46 and 47 are respectively interposed in the upper interface S1 and the lower interface S2 between the convex portion 45 and the concave portion 35 (see FIG. 1). For this reason, even if relative displacement occurs between the support bar 40 and the casing 20 and the lower half portion 20A of the casing 20 moves to the right, the support bar 40 is moved to the lower half of the nozzle diaphragm 30 by the reamer pins 46 and 47. It is securely fixed to the part 30A side. As a result, the support bar 40 does not rotate due to a clockwise bending moment with the point A as a fulcrum, and the nozzle diaphragm 30 does not float.

  Further, as shown in FIG. 1, a back side interface S3 is formed between the convex portion 45 and the concave portion 35, and a gap G1 having a predetermined thickness is formed on the back side interface S3. . As a result, relative displacement occurs between the support bar 40 and the casing 20, and when the lower half 20 </ b> A of the casing 20 moves to the right side, the bending rigidity with respect to the clockwise bending moment applied to the support bar 40 is increased. Can be increased.

  Furthermore, since the upper interface S1 and the lower interface S2 formed between the convex portion 45 and the concave portion 35 both have a gap of 0 to 0.1 mm, the gap between the upper interface S1 and the lower interface S2 is made small. Thus, the bending rigidity with respect to the bending moment in the clockwise direction applied to the support bar 40 can be further increased.

  Furthermore, since the gap G2 between the upper half portion 20B of the casing 20 and the spacer 49 is 0.15 to 0.30 mm, solid particles contained in the vapor enter the gap G2, and the upper half portion It is possible to prevent the portion 20B and the spacer 49 from sticking to each other.

  Both the adjustment shim 48 and the spacer 49 are made of a carbon sliding material. For this reason, even if a relative displacement occurs between the support bar 40 and the casing 20 and the lower half 20A of the casing 20 moves to the right side, the support bar 40 has the lower half 20A and the upper half of the casing 20. It can slide with respect to 20B.

  For this reason, even if the lower half portion 20A of the casing 20 moves to the right side, a clockwise bending moment about the point A is not applied to the support bar 40 from the casing 20 side.

<Second Embodiment>
Next, a second embodiment of a nozzle diaphragm mounting structure for a steam turbine will be described with reference to FIGS.

  In the second embodiment shown in FIGS. 5A and 5B, the same parts as those in the first embodiment shown in FIGS.

  As shown in FIG. 5 (a), a nozzle diaphragm mounting structure 10 for a steam turbine includes a casing 20 having a lower half portion 20A and an upper half portion 20B, a casing 20 and a lower half portion 30A and an upper half portion. And a nozzle diaphragm 30 having a portion 30B (see FIGS. 1 and 2).

  A support bar 40 that holds the nozzle diaphragm 30 is provided between the casing 20 and the nozzle diaphragm 30. Of these, the lower half 30A of the nozzle diaphragm 30 has a recess 35 extending in the horizontal direction, and the support bar 40 is fitted into the recess 35 of the lower half 30A of the nozzle diaphragm 30 and also has a protrusion 45 extending in the horizontal direction. Have

  As shown in FIG. 5A, the convex portion 45 and the concave portion 35 form an upper interface S1 and a lower interface S2 above and below.

  The support bar 40 is connected to the lower half 20A and the upper half 20B of the casing 20 via an adjustment shim 48 provided on the lower surface of the support bar 40 and a spacer 49 provided on the upper surface of the support bar 40. It is sandwiched and fixed between them (see FIGS. 1 and 2).

  The lower half 30 </ b> A of the nozzle diaphragm 30 is provided with a vertical groove 52, and the support bar 40 is provided with a vertical protrusion 53 that engages with the vertical groove 52. Furthermore, a reamer pin 49 extending in the horizontal direction through the vertical groove 52 and the vertical protrusion 53 is provided.

  In FIG. 5A, since a reamer pin 49 extending in the horizontal direction through the vertical groove 52 and the vertical protrusion 53 is provided, the support bar 40 is connected to the lower half 30A side of the diaphragm 30 by the reamer pin 49. Can be securely fixed. As a result, even if the lower half 20A of the casing 20 moves, the support bar 40 does not rotate with a bending moment applied, and the lower half 30A of the diaphragm 30 does not float.

  In the embodiment shown in FIG. 5A, a single vertical groove 52 is provided in the lower half 30A of the nozzle diaphragm 30, and the support bar 40 is engaged with the vertical groove 52 in a single vertical direction. In the example shown in FIG. 5B, a pair of vertical grooves 52a and 52b are provided in the lower half 30A of the nozzle diaphragm 30, and the vertical grooves 52a are provided in the support bar 40. , 52b may be provided with a pair of vertical protrusions 53a, 53b.

  Moreover, although the vertical groove | channel 52 was provided in the lower half part 30A of the nozzle diaphragm 30, and the vertical direction protrusion 53 was provided in the support bar 40, the vertical direction protrusion 53 was shown in the lower half part 30A of the nozzle diaphragm 30. The vertical groove 52 may be provided in the support bar 40.

<Third Embodiment>
Next, a third embodiment of a nozzle diaphragm mounting structure for a steam turbine will be described with reference to FIGS.

  In the third embodiment shown in FIGS. 6A and 6B, the same parts as those in the first embodiment shown in FIGS.

  As shown in FIG. 6, a structure 10 for attaching to a nozzle diaphragm of a steam turbine includes a casing 20 having a lower half 20A and an upper half 20B, and a casing 20 having a lower half 30A and an upper half 30B. (See FIG. 1 and FIG. 2).

  Further, a support bar 40 that holds the nozzle diaphragm is provided between the casing 20 and the nozzle diaphragm 30. Of these, the lower half 30A of the nozzle diaphragm 30 has a recess 35 extending in the horizontal direction, and the support bar 40 is fitted into the recess 35 of the lower half 30A of the nozzle diaphragm 30 and has a protrusion 45 extending in the horizontal direction. Have.

  Moreover, as shown to Fig.6 (a), the convex part 45 and the recessed part 35 form the upper interface S1 in the upper direction.

  Further, the support bar 40 is sandwiched and fixed between the lower half portion 20A and the upper half portion 20B of the casing 20 via a spacer 49 provided on the upper surface of the support bar 40.

  Further, a vertical groove 54 is provided in the lower half portion 30 </ b> A of the nozzle diaphragm 30, and a vertical protrusion 55 that engages in the vertical groove 54 is provided in the support bar 40. The vertical grooves 54 and the vertical protrusions 55 are provided with each other to form a groove structure.

Further, in the lower half 30A of the nozzle diaphragm 30, a support bar entry space 58 for inserting the support bar 40 from below into the lower half 30A and attaching to the lower half 30A is formed below the support bar 40. Has been.
In FIG. 6A, since the vertical groove 54 of the lower half 30A of the diaphragm 30 and the vertical protrusion 55 of the support bar 40 constitute a dovetail structure, the vertical groove 54 having this dovetail structure is provided. And the vertical protrusion 55 can securely fix the support bar 40 to the lower half 30 </ b> A side of the diaphragm 30. As a result, even if the lower half 20A of the casing 20 moves, a bending moment is not applied to the support bar 40 and the support bar 40 does not rotate or the lower half 30A of the diaphragm 30 does not float.

  In the embodiment shown in FIG. 6A, an example in which the vertical groove 54 constituting the dovetail structure is provided in the lower half 30A of the diaphragm 30 and the vertical protrusion 55 is provided in the support bar 40 is shown. However, the present invention is not limited thereto, and the vertical groove 54 is provided on the diaphragm 40 side, the vertical protrusion 56 is provided on the diaphragm 30A, and the vertical groove 57 and the vertical protrusion 56 constitute a groove structure. Good.

  Moreover, said embodiment is an illustration, Comprising: The range of invention is not limited to them, A various deformation | transformation is possible.

1 steam turbine, 2 rotors, 3 blades, 10 nozzle diaphragm mounting structure, 20 casing, 20A lower half, 20B upper half, 30 nozzle diaphragm, 30A lower half, 30B upper half, 35 recess, 40 support bar 45, 46, 47 reamer pins, 52, 52a, 52b vertical grooves, 53, 53a, 53b vertical protrusions, 54 vertical grooves, 55 vertical protrusions, 56 vertical protrusions, 57 vertical grooves , S1 upper interface, S2 lower interface, S3 back interface

Claims (7)

In the nozzle diaphragm mounting structure of the steam turbine,
A casing, a nozzle diaphragm provided in the casing, and a support bar interposed between the casing and the nozzle diaphragm;
The nozzle diaphragm has a recess extending in the horizontal direction, the support bar is fitted in the recess and has a projection extending in the horizontal direction,
The convex portion forms an upper interface and a lower interface with the concave portion, and a reamer pin extending in the horizontal direction along the upper interface or the lower interface is provided on either the upper interface or the lower interface. Nozzle diaphragm mounting structure for steam turbines.   2. The nozzle diaphragm mounting structure for a steam turbine according to claim 1, wherein a gap between each of the upper interface and the lower interface is 0 to 0.1 mm.   2. The nozzle diaphragm mounting structure for a steam turbine according to claim 1, wherein the convex portion and the concave portion are in contact with each other to form a back side interface.   The casing has an upper half and a lower half, the support bar is sandwiched between the upper half and the lower half, and a spacer is interposed between the support bar and the upper half. 2. The nozzle diaphragm mounting structure for a steam turbine according to claim 1, wherein a gap between the upper half and the spacer is 0.15 to 0.30 mm. A shim is interposed between the support bar and the lower half casing,
The nozzle diaphragm mounting structure for a steam turbine according to claim 4, wherein the spacer and the shim include a carbon sliding material. In the nozzle diaphragm mounting structure of the steam turbine,
A casing, a nozzle diaphragm provided in the casing, and a support bar interposed between the casing and the nozzle diaphragm;
The nozzle diaphragm has a recess extending in the horizontal direction, the support bar is fitted in the recess and has a projection extending in the horizontal direction,
One of the nozzle diaphragm and the support bar is provided with a vertical groove, and the other is provided with a vertical protrusion that engages with the vertical groove.
A steam diaphragm nozzle diaphragm mounting structure comprising a reamer pin extending in a horizontal direction through the vertical groove and the vertical protrusion. In the nozzle diaphragm mounting structure of the steam turbine,
A casing, a nozzle diaphragm provided in the casing, and a support bar interposed between the casing and the nozzle diaphragm;
The nozzle diaphragm has a recess extending in the horizontal direction, the support bar is fitted in the recess and has a projection extending in the horizontal direction,
Either one of the nozzle diaphragm and the support bar is provided with a vertical groove, and the other is provided with a vertical protrusion that engages with the vertical groove and forms a groove structure with the vertical groove.
A nozzle diaphragm mounting structure for a steam turbine, wherein a space for entering a support bar is provided below the support bar in the nozzle diaphragm.

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