Turbine tip shroud removal feature
A tip shroud, comprising a plurality of tip shoes encircling a rotor assembly, in a turbine may deform due to thermal gradients experienced during operation of the turbine. This can make it difficult to remove the tip shroud during disassembly of the turbine. In an embodiment, to facilitate consistent and reliable removal of the tip shroud during each disassembly of the turbine, one or more, including potentially all, of the tip shoes of a tip shroud may be provided with one or more radially protruding puller hooks. Each puller hook enables an axial force to be transferred by one or more tools to an axially inner surface of the puller hook, to thereby produce axial movement of the tip shoe out of the tip shroud.
1 . A tip shoe for forming a tip shroud of a turbine having a longitudinal axis and a radial axis that is orthogonal to the longitudinal axis, the tip shoe comprising:
a body with an upstream end and a downstream end, relative to a longitudinal direction parallel to the longitudinal axis, the body including:
a first engagement portion protruding in a first radial direction parallel to the radial axis and configured to engage with a support ring of the turbine, and
a second engagement portion protruding in a second radial direction parallel to the radial axis and configured to engage with the support ring of the turbine; and
a puller hook protruding from the downstream end in a third radial direction parallel with the first engagement portion and the second engagement portion, and spaced apart from a downstream side of the second engagement portion to define a void between an upstream side of the puller hook and the downstream side of the second engagement portion,
the downstream end comprising a continuous surface extending from the second engagement portion to the puller hook, and the puller hook having an axially inner surface on the upstream side of the puller hook,
the puller hook being configured so that a tool can be used to push the tip shoe out of engagement with the support ring by inserting a first segment of the tool into the void and into contact with the axially inner surface of the puller hook, positioning a second segment of the tool radially outward of the puller hook, and applying a force to the second segment of the tool.
2 . The tip shoe of claim 1 ,
wherein the first radial direction of the first engagement portion is an outward direction from the longitudinal axis.
3 . The tip shoe of claim 1 ,
wherein the first radial direction of the first engagement portion and the second radial direction of the second engagement portion are an outward direction from the longitudinal axis and the first engagement portion and the second engagement portion further extend along the longitudinal direction.
4 . The tip shoe of claim 1 , further comprising:
an aperture positioned in the first engagement portion and extending in the longitudinal direction.
5 . The tip shoe of claim 4 , further comprising:
an axial pin positioned in the aperture and configured to extend into the support ring.
6 . The tip shoe of claim 1 ,
wherein the puller hook extends along an entire downstream edge of the body.
7 . The tip shoe of claim 1 ,
wherein the third radial direction of the puller hook is an outward direction from the longitudinal axis.
8 . The tip shoe of claim 1 wherein:
the first engagement portion includes a first flange extending in the longitudinal direction, and
the second engagement portion includes a second flange extending in the longitudinal direction.
9 . A turbine having a longitudinal axis and a radial axis that is orthogonal to the longitudinal axis, the turbine comprising:
a rotor assembly encircling the longitudinal axis;
a tip shroud encircling the rotor assembly; and
a support ring encircling the tip shroud;
the tip shroud including a plurality of tip shoes, each tip shoe including:
a body with an upstream end and a downstream end, relative to a longitudinal direction parallel to the longitudinal axis, the body including:
a first engagement portion protruding in a first radial direction parallel to the radial axis and configured to engage with the support ring, and
a second engagement portion protruding in a second radial direction parallel to the radial axis and configured to engage with the support ring; and
a puller hook protruding from the downstream end in a third radial direction parallel with the first engagement portion and the second engagement portion, and spaced apart from a downstream side of the second engagement portion to define a void between an upstream side of the puller hook and the downstream side of the second engagement portion,
the downstream end comprising a continuous surface extending from the second engagement portion to the puller hook, and the puller hook having an axially inner surface,
the puller hook being configured so that a tool can be used to push the tip shoe out of engagement with the support ring by inserting a first segment of the tool into the void and into contact with the axially inner surface of the puller hook, positioning a second segment of the tool radially outward of the puller hook, and applying a force to the second segment of the tool.
10 . The turbine of claim 9 ,
wherein the first radial direction of the first engagement portion and the second radial direction of the second engagement portion is an outward direction from the longitudinal axis.
11 . The turbine of claim 9 ,
wherein each tip shoe further comprises an aperture positioned in the first engagement portion and extending in the longitudinal direction.
12 . The turbine of claim 11 , further comprising:
an axial pin positioned in the aperture and extending into the support ring.
13 . The turbine of claim 9 ,
wherein the puller hook extends along an entire downstream edge of the body.
14 . The turbine of claim 9 ,
wherein the third radial direction of the puller hook protrudes outward from the longitudinal axis.
15 . The turbine of claim 9 , further comprising:
a snap ring encircling the longitudinal axis and mounted into a radial recess in the support ring and abutting the second engagement portion of each tip shoe.
16 . The turbine of claim 9 ,
wherein the support ring includes a segment to provide a surface for the tool to contact when the tool is used to push the tip shoe out of engagement with the support ring.
17 . The turbine of claim 9 , wherein:
the first engagement portion includes a first flange extending in the longitudinal direction, and
the second engagement portion includes a second flange extending in the longitudinal direction.
18 . A method of removing a tip shoe from a turbine having a longitudinal axis and a radial axis that is orthogonal to the longitudinal axis, the tip shoe having a body with an upstream end and a downstream end, relative to a longitudinal direction parallel to the longitudinal axis, and a puller hook protruding from the downstream end in a radial direction parallel to the radial axis, the method comprising:
placing a first segment of a tool in contact with an axially inner surface on an upstream side of the puller hook;
positioning a second segment of the tool radially outward of the puller hook, the second segment being opposite the first segment; and
applying a force to the second segment of the tool to move the tip shoe in a downstream direction.
19 . The method of claim 18 , further comprising:
placing a middle segment of the tool in contact with a support ring of the turbine, the middle segment located between the first segment and the second segment,
wherein applying the force to the second segment of the tool includes applying a force in an upstream direction, whereby the tool is pivoted on the support ring and a force is applied to the axially inner surface on the upstream side of the puller hook to move the tip shoe in the downstream direction.