Shaft seal mechanism

摘要

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.

主权项

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.