Steam turbine

Patent metadata

Field	Value
Publication number	US-11156089-B2
Application number	US-201515551625-A
Country	US
Kind code	B2
Filing date	Feb 23, 2015
Priority date	Feb 23, 2015
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

Provided is a steam turbine in which, among a plurality of stages thereof, a stage that is disposed furthest upstream is a speed-adjusting stage, at least one stage that is disposed downstream of the speed-adjusting stage is a medium-pressure stage, and at least one stage that is disposed downstream of the medium-pressure stage is a low-pressure stage. The speed-adjusting stage is an impulse stage. The medium-pressure stage is a medium reaction degree impulse stage in which the degree of reaction is a medium degree of reaction of 10-40%. The low-pressure stage is a reaction stage having a higher degree of reaction than the medium-pressure stage.

First claim

The invention claimed is:

1. A steam turbine, comprising:
a rotor shaft which rotates about an axis line;
a plurality of rotor blade rows which are fixed to an outer periphery of the rotor shaft and are arranged in an axial direction in which the axis line extends; and
a stator blade row which is adjacent to an upstream side in the axial direction of the rotor blade row for each of the plurality of rotor blade rows,
wherein, among a plurality of stages configured of a set of the rotor blade row and the stator blade row disposed to be adjacent to the upstream side of the rotor blade row, a stage disposed on the most upstream side is a speed-adjusting stage, at least one stage, including a second stage, disposed on a downstream side of the speed-adjusting stage and adjacent to the speed-adjusting stage is a medium-pressure stage, and at least one stage disposed on a downstream side of the medium-pressure stage is a low-pressure stage,
wherein the speed-adjusting stage is an impulse stage and configured to adjust a flow rate of the steam fed to the stages on a downstream side of a first stage so as to adjust a rotation speed of a rotor having the rotor shaft,
wherein the medium-pressure stage is a medium reaction degree impulse stage in which a degree of reaction is a medium degree of reaction of 25% to 35%, and
wherein the low-pressure stage is a reaction stage having a degree of reaction which is higher than the degree of reaction of the medium-pressure stage,
wherein the rotor shaft includes a plurality of partition portions which spread in a radial direction based on the axis line and are arranged in the axial direction with a gap therebetween,
wherein the rotor blade row of the medium-pressure stage is fixed to an outer peripheral portion of any one partition portion of the plurality of partition portions,
wherein a balance hole penetrating in the axial direction is formed in a medium-pressure stage partition portion which is the partition portion to which the rotor blade row of the medium-pressure stage is fixed,
wherein the stator blade row includes a plurality of stator blades which are arranged in a circumferential direction about the axis line and an inner ring which is disposed on the inside in a radial direction of the plurality of stator blades with respect to the axis line and to which the plurality of stator blade rows are fixed,
wherein the inner ring of the stator blade row configuring the medium-pressure stage faces the medium-pressure stage partition portion with a gap therebetween in the axial direction,
wherein the steam turbine further includes a seal which is fixed to the inner ring of the stator blade row configuring the medium-pressure stage and seals a portion between the inner ring and the medium-pressure stage partition portion on a portion positioned further outside in the radial direction with respect to the axis line than the balance hole,
wherein in the medium-pressure stage partition portion, an intermediate peripheral surface is formed in the radial direction with respect to the axis line further outside in the radial direction than the balance hole on the inner ring side of the medium-pressure stage partition portion, and
wherein the seal includes a radial fin having a tip portion which extends in the radial direction and faces the intermediate peripheral surface of the medium-pressure state partition portion.

2. The steam turbine according to claim 1 ,
wherein the medium-pressure stage is configured to include a plurality of stages, and
wherein degrees of reaction of the plurality of stages configuring the medium-pressure stage gradually increase from an upstream stage toward a downstream stage.

3. The steam turbine according to claim 1 ,
wherein deflection angles of a plurality of rotor blades configuring the rotor blade row of the medium-pressure stage are smaller than deflection angles of a plurality of rotor blades configuring the rotor blade row of the speed-adjusting stage and are greater than deflection angles of a plurality of rotor blades configuring the rotor blade row of the low-pressure stage.

4. The steam turbine according to claim 1 ,
wherein deflection angles of a plurality of stator blades configuring the stator blade row of the medium-pressure stage are smaller than deflection angles of a plurality of stator blades configuring the stator blade row of the speed-adjusting stage and are greater than deflection angles of a plurality of stator blades configuring the stator blade row of the low-pressure stage.

5. The steam turbine according to claim 1 ,
wherein a plurality of rotor blades configuring the rotor blade row of the medium-pressure stage are parallel blades.

6. A steam turbine, comprising:
a rotor shaft which rotates about an axis line;
a plurality of rotor blade rows which are fixed to an outer periphery of the rotor shaft and are arranged in an axial direction in which the axis line extends; and
a stator blade row which is adjacent to an upstream side in the axial direction of the rotor blade row for each of the plurality of rotor blade rows,
wherein, among a plurality of stages configured of a set of the rotor blade row and the stator blade row disposed to be adjacent to the upstream side of the rotor blade row, a stage disposed on the most upstream side is a speed-adjusting stage, at least one stage, including a second stage, disposed on a downstream side of the speed-adjusting stage and adjacent to the speed-adjusting stage is a medium-pressure stage, and at least one stage disposed on a downstream side of the medium-pressure stage is a low-pressure stage,
wherein the speed-adjusting stage is an impulse stage and configured to adjust a flow rate of the steam fed to the stages on a downstream side of a first stage so as to adjust a rotation speed of a rotor having the rotor shaft,
wherein the medium-pressure stage is a medium reaction degree impulse stage in which a degree of reaction is a medium degree of reaction of 25% to 35%,
wherein the low-pressure stage is a reaction stage having a degree of reaction which is higher than the degree of reaction of the medium-pressure stage,
wherein a speed ratio is defined as a ratio of an absolute speed of the steam in the outlets of stator blades configuring a stage among the plurality of stages with respect to a peripheral speed of rotor blades configuring the stage,
an optimum speed ratio is defined as the speed ratio at which turbine efficiency reaches maximum, and
the optimum speed ratio of the medium-pressure stage is smaller than the optimum speed ratio of the speed-adjusting stage and is greater than the optimum speed ratio of the low-pressure stage.

7. A steam turbine, comprising:
a rotor shaft which rotates about an axis line;
a plurality of rotor blade rows which are fixed to an outer periphery of the rotor shaft and are arranged in an axial direction in which the axis line extends; and
a stator blade row which is adjacent to an upstream side in the axial direction of the rotor blade row for each of the plurality of rotor blade rows,
wherein, among a plurality of stages configured of a set of the rotor blade row and the stator blade row disposed to be adjacent to the upstream side of the rotor blade row, a stage disposed on the most upstream side is a speed-adjusting stage, at least one stage, including a second stage disposed on a downstream side of the seed-adjusting stage and adjacent to the speed-adjusting stage is a medium-pressure stage, and at least one stage disposed on a downstream side of the medium-pressure stage is a low-pressure stage,
wherein the speed-adjusting stage is an impulse stage and configured to adjust a flow rate of the steam fid to the stages on a downstream side of a first stage so as to adjust a rotatio

Assignees

• Mitsubishi Heavy Ind Compressor Corp

Inventors

• Koda Takuro

Classifications

• F01D17/162

  for axial flow, i.e. the vanes turning around axes which are essentially perpendicular to the rotor centre line (F01D17/167 takes precedence) · CPC title

• F01D5/142

  of the blades of successive rotor or stator blade-rows · CPC title

• F01D1/16 Primary

  characterised by having both reaction stages and impulse stages · CPC title

• F05B2240/12

  Fluid guiding means, e.g. vanes · CPC title

• F05B2240/30

  Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor · CPC title