Shaft seal mechanism

Patent metadata

Field	Value
Publication number	US-9593588-B2
Application number	US-201313772873-A
Country	US
Kind code	B2
Filing date	Feb 21, 2013
Priority date	Feb 25, 2011
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

An inner wall surface of a low-pressure-side side plate opposite to a lateral surface of a thin plate is formed along a direction crossing an axial direction of a rotating shaft such that a gap between the inner wall surface and the thin plate gradually decreases from a radially inner side toward a radially outer side of the low-pressure-side side plate.

First claim

The invention claimed is:

1. A shaft seal mechanism blocking fluid flow through an annular space between a rotating shaft and a stationary portion in an axial direction of the rotating shaft, the shaft seal mechanism comprising: a leaf seal housing held inside the stationary portion; a plurality of thin plates provided in a circumferential direction of the rotating shaft with gaps formed between the plurality of thin plates, wherein each of the plurality of thin plates comprises an outer circumferential base end fixed in the leaf seal housing and an inner circumferential leading end subtending an acute angle to a circumferential surface of the rotating shaft, the plurality of thin plates having a width in the axial direction of the rotating shaft and contacting the circumferential surface of the rotating shaft in a slidable manner; and a low-pressure-side side plate and a high-pressure-side side plate provided on a low pressure side and a high pressure side, respectively, of the leaf seal housing, sandwiching each of the plurality of thin plates between the side plates, wherein the low-pressure-side side plate comprises a first inner circumferential surface and a second inner circumferential surface extending along the axial direction of the rotating shaft and an inner wall surface of the low-pressure-side side plate that connects the first inner circumferential surface and the second inner circumferential surface and that is opposite to a lateral surface of the plurality of thin plates, wherein the inner wall surface is formed along a direction crossing the axial direction of the rotating shaft such that a gap between the inner wall surface and the plurality of thin plates gradually decreases from an end at a radially inner side of the low-pressure-side side plate that is connected to the second inner circumferential surface through an end at a radially outer side of the low-pressure-side side plate that is connected to the first inner circumferential surface; wherein the low-pressure-side side plate further comprises an outer wall surface that connects the second inner circumferential surface and the leaf seal housing, and wherein the outer wall surface extends along a direction crossing the axial direction of the rotating shaft such that a thickness of the low-pressure-side side plate gradually increases from an end connected to the second inner circumferential surface through an end connected to the leaf seal housing.

2. The shaft seal mechanism according to claim 1 , wherein the inner wall surface of the low-pressure-side side plate and the outer wall surface of the low-pressure-side side plate are arranged along the circumferential direction of the rotating shaft and are connected with each other through a communication hole extending along the axial direction of the rotating shaft.

3. A turbine comprising the shaft seal mechanism according to claim 2 , wherein the turbine transduces thermal energy of fluid into mechanical rotational energy to generate power by guiding the fluid at elevated temperature and pressure to a casing to blow the fluid against a blade on a rotating shaft rotatably supported inside the casing.

4. A turbine comprising the shaft seal mechanism according to claim 1 , wherein the turbine transduces thermal energy of fluid into mechanical rotational energy to generate power by guiding the fluid at elevated temperature and pressure to a casing to blow the fluid against a blade on a rotating shaft rotatably supported inside the casing.

5. The shaft seal mechanism according to claim 1 ,
wherein the inner wall surface, the second inner circumferential surface, and the outer wall surface form a shape appearing like a wedge in a cross-sectional view.

6. A shaft seal mechanism blocking fluid flow through an annular space between a rotating shaft and a stationary portion in an axial direction of the rotating shaft, the shaft seal mechanism comprising: a leaf seal housing held inside the stationary portion; a plurality of thin plates provided in a circumferential direction of the rotating shaft with gaps formed between the plurality of thin plates, wherein each of the thin plates comprises an outer circumferential base end fixed in the leaf seal housing and an inner circumferential leading end subtending an acute angle to a circumferential surface of the rotating shaft, the plurality of thin plates having a width in the axial direction of the rotating shaft and contacting the circumferential surface of the rotating shaft in a slidable manner; and a low-pressure-side side plate and a high-pressure-side side plate provided on a low pressure side and a high pressure side, respectively, of the leaf seal housing, sandwiching each of the plurality of thin plates between the side plates, wherein the low-pressure-side side plate comprises a first inner circumferential surface extending along the axial direction of the rotating shaft, a rounded curved surface projecting toward the inner circumferential leading end of the plurality of thin plates, and an inner wall surface of the low-pressure-side side plate that connects the first inner circumferential surface and the rounded curved surface and that is opposite to a lateral surface of the plurality of thin plates, wherein the inner wall surface is formed along a direction crossing the axial direction of the rotating shaft such that a gap between the inner wall surface and the plurality of thin plates gradually decreases from an end at a radially inner side of the low-pressure-side side plate that is connected to the rounded curved surface through an end at a radially outer side of the low-pressure side plate that is connected to the first inner circumferential surface, wherein the low-pressure-side side plate further comprises an outer wall surface that connects the rounded curved surface and the leaf seal housing, wherein the inner wall surface of the low-pressure-side side plate and the outer wall surface of the low-pressure-side side plate are connected together by the rounded curved surface, and wherein the outer wall surface extends along a direction crossing the axial direction of the rotating shaft such that a thickness of the low-pressure-side side plate gradually increases from an end connected to the rounded curved surface through an end connected to the leaf seal housing.

7. The shaft seal mechanism according to claim 6 , wherein the inner wall surface of the low-pressure-side side plate and the outer wall surface of the low-pressure-side side plate are arranged along the circumferential direction of the rotating shaft and are connected with each other through a communication hole extending along the axial direction of the rotating shaft.

8. A turbine comprising the shaft seal mechanism according to claim 7 , wherein the turbine transduces thermal energy of fluid into mechanical rotational energy to generate power by guiding the fluid at elevated temperature and pressure to a casing to blow the fluid against a blade on a rotating shaft rotatably supported inside the casing.

9. A turbine comprising the shaft seal mechanism according to claim 6 , wherein the turbine transduces thermal energy of fluid into mechanical rotational energy to generate power by guiding the fluid at elevated temperature and pressure to a casing to blow the fluid against a blade on a rotating shaft rotatably supported inside the casing.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Morimoto Hitoshi
• Tsukagoshi Keizo
• Masada Junichiro
• Takahashi Tatsuji
• Araki Masato
• Shinohara Tanehiro
• Uehara Hidekazu

Classifications

• F04D29/10

  Shaft sealings · CPC title

• F05D2240/57

  Leaf seals · CPC title

• F05D2250/75

  given by its similarity to a letter, e.g. T-shaped · CPC title

• F04D29/102

  especially adapted for elastic fluid pumps · CPC title

• F01D11/02 Primary

  by non-contact sealings, e.g. of labyrinth type (for sealing space between rotor blade tips and stator F01D11/08) · CPC title