JPH04295106A - Steam turbine - Google Patents

Abstract

PURPOSE:To absorb thermal expansion of a casing even if a front bearing stand is fixed on a base by enabling that thermal expansion of the casing and a condenser is absorbed by curving of a bendable support stud fixed on the base for supporting the casing and the condenser. CONSTITUTION:Journal parts 22, 24 provided in front and rear of the rotor 20 in a steam turbine are supported by respective front and rear bearings 23, 25. The rear bearing 25 is stored in a bearing casing 27 and fixed through a bearing support 28. The bearing casing 27 is supported by a plurality of support 29 which are fixed on the exhaust part of an outer casing 30, and the exhaust part of the outer casing 30 is fixed on the jointing flange part of a lower casing in an inner casing 31 by a bendable supporting stud 37 which is extended upward while being screwed in the base plate on a base 26. Thermal expansion at the time of operation of a turbine is absorbed by curving of the supporting stud 37 for supporting respectively the outer casing 30 and the condenser 45 connected to the exhaust part of the outer casing 30.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine having a support structure for supporting a turbine and a condenser to allow thermal expansion of the turbine and condenser due to steam temperature during operation of the steam turbine. .

0002

2. Description of the Related Art Conventionally, a steam turbine equipped with a condenser has a structure shown in FIG. 7, in which the condenser is provided below a casing. In FIG. 7, a rotor 1 provided with moving blades (not shown) is surrounded by a casing 2 provided with the moving blades and stationary blades forming blade stages.

A journal portion 3 passing through the casing 2 on the steam inlet side of the rotor 1 is supported by a thrust bearing 5 and a journal bearing 6 fixed within a front bearing pedestal 4. Further, a journal portion 7 passing through the casing 2 on the steam outlet side of the rotor 1 is supported by a journal bearing 9 fixed within a rear bearing stand 8.

[0004] A condenser 10 is provided below the casing 2 and connected to an exhaust section 11.

Here, the rear bearing pedestal 8 is placed on the foundation, while the casing 2 is placed on the foundation at the center of the exhaust section 11, and the condenser 1 is placed on the foundation.
0 is also fixed to the foundation. On the other hand, the front bearing stand 4 is connected to the front part of the casing 2 by a key at the connecting part 13, and as shown in FIG.
It is installed via 2. As a result, the front bearing pedestal 4 slides on the sliding plate 12 from a fixed point fixed to the aforementioned foundation of the casing 2 due to thermal expansion of the casing 2 during turbine operation. Note that 4a is the case of the bearing stand, 4
b is the lid.

Further, a guide mechanism 19 is provided to guide the direction of expansion of the casing 2 due to thermal expansion in the axial direction of the rotor 1.
is provided at the lower part of the front bearing stand 4.

[0007] The guide mechanism 19 is connected to the rotor 1 of the front bearing stand 4.
A convex body 15 provided on the base plate 14 below corresponding to the axis of the
, the sliding key 16 attached to both sides, and the case 4
It is formed from a concave body 18 that is provided on the bottom plate 17 of a and slides on the surface of the sliding key 16 with the sliding key 16 therebetween.

With this configuration, when the steam turbine is operated by supplying steam, the rotor 1 and the casing 2 thermally expand due to the steam temperature. At this time, the rotor 1 slides in the journal bearing 9 and extends from the thrust bearing 5 in the front bearing pedestal 4, which is a fixed point, toward the rear bearing pedestal 8. On the other hand, the casing 2 is connected from the center of the exhaust section, which is the fixed point, to the front bearing stand 4.
Thermal expansion occurs in the direction of At this time, since the casing 2 is connected to the front bearing stand 4 by the connecting part 13, the casing 2
Due to thermal expansion, the front bearing stand 4 slides on the sliding plate 12 and moves. In this case, the front bearing pedestal 4 slides on the surface of the sliding key 16 by the guide mechanism 19, and the casing 2 extends in the axial direction of the rotor 1.

[0009]

[Problems to be Solved by the Invention] Since the condenser 10 is installed below the casing 2, by fixing the center of the exhaust part of the casing to the foundation, it is possible to
Thermal expansion of the casing 2 is absorbed by sliding the front bearing stand 4 on the foundation. In this case, a base plate 14 is fixed to the foundation under the front bearing base 4, and the front bearing base 4 and the base plate 1 are fixed to the foundation.
4, a sliding mechanism consisting of a sliding plate 16 and the like is required, which has the disadvantage of increasing costs.

Furthermore, since the front bearing pedestal 4 is not fixed to the foundation and only carries the weight of the turbine, the front bearing pedestal 4 is lifted up by external forces such as turbine reaction force and piping force, and as a result, the rotor 1 is There is a problem in that it displaces the shaft center and causes vibration.

An object of the present invention is to provide a steam turbine that can absorb thermal expansion of the casing even when the front bearing pedestal is fixed to the foundation.

0012

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, one journal portion of a rotor is supported in a fixed position, and a front bearing is fixed to a foundation; A casing that surrounds the rotor and extends from the journal part, the front bearing side of which is fixed to the foundation, a rear bearing that is built into this casing and supports the other journal part of the rotor that is fixed to the casing, and is connected to the exhaust part of the casing. The condenser is arranged in series with the rotor, the casing part on the exhaust side side and the condenser are supported, and the support studs are fixed to the foundation and have bendable flexibility and extend upward. , and a guide mechanism that guides thermal expansion of the casing due to steam temperature during turbine operation in the axial direction of the rotor.

[0013] Also, a front bearing supports one journal part of the rotor in a fixed position and is fixed to the foundation, and a rear bearing supports the other journal part of the rotor and is fixed to the foundation. , a casing that surrounds the rotor section between the front bearing and the rear bearing and whose front bearing side is fixed to the foundation, a condenser connected to the exhaust section of this casing and arranged on both sides of the rotor, and an exhaust section. A flexible support stud that supports the side casing part and the condenser, is fixed to the foundation and extends upward, and guides thermal expansion of the casing due to steam temperature during turbine operation in the direction of the rotor axis. A steam turbine is constructed by including a guide mechanism.

[0014]

[Operation] During operation of a steam turbine, the rotor and casing undergo thermal expansion due to the steam temperature. At this time, the rotor thermally expands toward the rear bearing, which is built into the casing and fixed to the casing, using the front bearing as a fixing point. On the other hand, the casing and condenser are guided in the axial direction of the rotor from the casing fixing point on the front bearing side toward the rear bearing by the guide mechanism, and thermally expand. In this case, the thermal expansion of the casing and condenser is absorbed by the curvature of an upwardly extending bendable support stud fixed to the foundation supporting the casing and condenser.

[0015] Furthermore, in a steam turbine in which a condenser is connected to the exhaust part of the casing and is disposed on both sides of the rotor,
During operation of the steam turbine, the rotor thermally expands toward the rear bearing, with the front bearing as a fixed point, as described above. On the other hand, the condensers disposed on both sides of the casing and rotor also thermally expand by being guided in the axial direction of the rotor by the guide mechanism toward the rear bearing with the front bearing side of the casing as a fixed point, as described above. In this case, thermal expansion of the casing and condenser is absorbed by the curvature of an upwardly extending bendable support stud fixed to the foundation supporting the casing and condenser.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below based on the drawings. FIG. 1 is a longitudinal cross-sectional view of a steam turbine according to an embodiment of the present invention, FIG. 2 is a side view of the steam turbine of FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA of FIG. In addition, in FIGS. 1 to 3, parts that are the same as those in the conventional example shown in FIGS. 7 and 8 are given the same reference numerals, and their explanations will be omitted. In FIGS. 1 to 3, the rotor 20 includes rotor blades, and one journal portion 2 of the rotor 20
2 is supported by a front bearing 23 consisting of a thrust bearing and a journal bearing, while the other journal part 24 is supported by a rear bearing 25 consisting of a journal bearing.

The front bearing 23 is built into and fixed to a front bearing stand 21 fixed to a foundation 26. On the other hand, the rear bearing 25 is built into a bearing casing 27 and fixed via a bearing support 28, and the bearing casing 27 is supported by a plurality of supports 29 fixed to an exhaust section of an external casing 30, which will be described later.

An inner casing 31 surrounds the rotor 20 with moving blades and stator vanes forming blade stages.

The outer casing 30 is composed of an upper casing and a lower casing and surrounds the inner casing 31.
The rotor blade downstream of the inner casing 31 and the stationary blade forming a blade stage are provided. The exhaust portion of the outer casing 30 is provided with the rear bearing 25 as described above. In addition,
34 is a main steam inlet, and 35 is a bleed steam inlet.

Further, the outer casing 30 has a front part of the lower casing connected to a support plate 33 provided at the lower part of the front bearing stand 21.
is supported and fixed. On the other hand, the external casing 30
The exhaust section at the rear of the base plate 36 (
A bendable support stud 37 screwed into the flange 38 of the lower casing on both sides at the level of the axis of the rotor 20 and a support plate 39 provided at the same level are connected to a nut by means of a bendable support stud 37 screwed into the flange 38 and a support plate 39 provided at the same level. It is concluded and supported by.

A guide mechanism 40 is provided on the base 26 at the bottom of the exhaust section of the outer casing 30 for guiding the thermal expansion of the outer casing 30 due to the steam temperature in the axial direction of the rotor 20.

The guide mechanism 40 is mounted on the base 26 as shown in FIG.
It consists of a guide plate 43 having a convex body 42 which is fixed to and has a sliding key 41 attached thereto, and a concave body 44 which is provided at the bottom of the outer casing 30 and has a groove 44a which holds the sliding key 41 therebetween.

The condenser 45 is connected to the exhaust part of the outer casing 30 and is arranged in series with the outer casing 30. The condenser 45 is fastened with a nut to a support plate 47 provided on the outer wall of the condenser 45 at the same level as the flange 38 by a bendable support stud 37 screwed into a base plate 46 fixed to the foundation 26. and is supported.

With this structure, when steam is supplied to the steam turbine from the main steam inlet 34, the rotor 20 is rotated by the work of the steam at the blade stages. The steam that has done work in the blade stages flows through the exhaust section of the outer casing 30 to the condenser 45, where it becomes condensed water and is maintained at a predetermined pressure below atmospheric pressure.

During operation of such a turbine, the rotor 20
thermally expands from the fixed point of the front bearing 23 towards the rear bearing 25. On the other hand, the external casing 30 and the condenser 45 are guided in the axial direction of the rotor 20 from the fixed point of the support plate 33 of the front bearing stand 21 toward the rear bearing 25 by sliding on the sliding key 41 surface of the guide mechanism 40. thermal expansion. Thermal expansion at this time is absorbed by the curvature of the support studs 37 that support the outer casing 30 and the condenser 45, respectively.

Here, the length of the support stud 37 is equal to the length of the foundation 26.
Since the length from The perpendicular displacement of the heart can be ignored.

FIG. 5 is a plan view of a steam turbine according to a different embodiment of the present invention, and FIG. 6 is a side view of the steam turbine of FIG. The differences in FIGS. 5 and 6 from the previous embodiment are as follows.

The rear bearing pedestal 50 is disposed outside the outer casing 30 and is fixed to the foundation. Condenser 51,5
1a is connected from the exhaust section of the outer casing 30 to both sides of the rotor via exhaust ducts 52, 52a. Note that 53 is a generator.

[0029] External casing 30 and condensers 51, 51a
are supported by a plurality of support studs 37, each having the same function as described above.

With this configuration, during turbine operation, the rotor thermally expands toward the rear bearing with the front bearing as the fixed point, as described above, and the outer casing 30, condenser 51,
Thermal expansion with respect to the support stud 37 is absorbed by the bending of the support stud 37 in the same manner as described above.

[0031]

As is clear from the above description, according to the present invention, the front bearing stand in which the front bearing is installed and the front part of the casing are respectively fixed to the foundation, and the exhaust gas located at the rear of the casing is The condensers arranged in series connected to the casing and the condensers arranged on both sides of the rotor from the exhaust part of the casing are each supported by bendable support studs fixed to the foundation and extending upward. Furthermore, by providing a guide mechanism in the casing that guides the thermal expansion of the casing due to steam temperature during turbine operation in the direction of the rotor axis, thermal expansion between the casing and condenser is prevented from curving the support studs during turbine operation. Therefore, there is no need to slide the front bearing stand on the foundation as in the prior art, and the sliding mechanism required for this is no longer necessary, resulting in cost reduction.

[0032] Also, since the front bearing stand is fixed to the foundation,
It is possible to prevent the casing of the front bearing pedestal from lifting up during thermal expansion, and the generation of vibrations due to this can be prevented.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a steam turbine equipped with a condenser according to an embodiment of the present invention;

FIG. 2 is a side view of a steam turbine equipped with the condenser of FIG. 1;

[
Figure 3: A-A sectional view of the steam turbine in Figure 2

[Figure 4] Figure 3
Detailed enlarged view of part B of

FIG. 5 is a plan view of a steam turbine with a condenser according to different embodiments of the invention;

FIG. 6 is a side view of a steam turbine equipped with the condenser of FIG. 5;

[
Figure 7: Schematic cross-sectional view of a steam turbine equipped with a conventional condenser

[Fig. 8] Detailed configuration diagram of the front bearing stand of the steam turbine in Fig. 7 as viewed from arrow C.

[Explanation of symbols]

1 Rotor 2 Casing 3 Journal section 7 Journal section 10 Condenser 20 Rotor 21 Front bearing stand 22 Journal section 24 Journal section 23 Front bearing 25 Rear bearing 26 Basics 29 Support 30 External casing 37 Support stud 40 Guidance mechanism 45 Condenser 51 Condenser 51a Condenser 50 Rear bearing stand

Claims (2)

[Claims] Claim 1: One journal part of a rotor is supported in a fixed position, and a front bearing is fixed to a foundation, and the rotor extending from the journal part is surrounded, and the front bearing side is fixed to the foundation. A casing, a rear bearing built into the casing and supporting the other journal part of the rotor fixed to the casing, a condenser connected to the exhaust part of the casing and arranged in series with the rotor, and an exhaust part. A flexible support stud is fixed to the foundation and extends upward to support the side casing and condenser, and guides thermal expansion of the casing due to steam temperature during turbine operation in the axial direction of the rotor. A steam turbine characterized in that it is equipped with a guide mechanism. 2. A front bearing that supports one journal part of the rotor in a fixed position and is fixed to the foundation; and a rear bearing that supports the other journal part of the rotor and is fixed to the foundation. , a casing that surrounds the rotor section between the front bearing and the rear bearing and whose front bearing side is fixed to the foundation, a condenser connected to the exhaust section of this casing and arranged on both sides of the rotor, and an exhaust section. A flexible support stud that supports the side casing part and the condenser, is fixed to the foundation and extends upward, and guides thermal expansion of the casing due to steam temperature during turbine operation in the direction of the rotor axis. A steam turbine characterized by comprising a guide mechanism.