US20140186160A1

US20140186160A1 - Slider seal

Info

Publication number: US20140186160A1
Application number: US13/730,892
Authority: US
Inventors: Conway Chuong; Matthew Budnick; Darrell Weidner
Original assignee: United Technologies Corp
Current assignee: RTX Corp
Priority date: 2012-12-29
Filing date: 2012-12-29
Publication date: 2014-07-03
Also published as: WO2014105598A1

Abstract

An assembly for a gas turbine engine includes a component, a seal element, and a seal cap. The component defines a pocket adapted to accept the seal element and the pocket allows for sliding movement of the component relative to the seal element. The seal cap overlying the pocket and the seal element.

Description

BACKGROUND

The invention relates to gas turbine engines, and more particularly to seals for components of gas turbine engines.
Gas turbine engines operate according to a continuous-flow, Brayton cycle. A compressor section pressurizes an ambient air stream, fuel is added and the mixture is burned in a central combustor section. The combustion products expand through a turbine section where bladed rotors convert thermal energy from the combustion products into mechanical energy for rotating one or more centrally mounted shafts. The shafts, in turn, drive the forward compressor section, thus continuing the cycle. Gas turbine engines are compact and powerful power plants, making them suitable for powering aircraft, heavy equipment, ships and electrical power generators. In power generating applications, the combustion products can also drive a separate power turbine attached to an electrical generator.
Slider seals are free floating seals that are used in gas turbine engines at probe and and/or pin locations. These seals are held in place by a spring-loaded C-clip or a fastener. The use of C-clips or fasteners for retention of the seal creates the need for close tolerance machining, adds additional parts and weight to the engine, and/or can create the potential for component wear or damage due to the C-clips or fasteners working loose due to vibration or creep yielding over the life cycle of the engine.

SUMMARY

An assembly for a gas turbine engine includes a component, a seal element, and a seal cap. The component defines a pocket adapted to accept the seal element and the pocket allows for sliding movement of the component relative to the seal element. The seal cap overlying the pocket and the seal element.
The assembly of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
the component comprises a seal carrier, and the pocket is disposed in the seal carrier, and wherein the seal carrier separates a first cavity of the gas turbine engine from a second cavity of the gas turbine engine;
the second cavity comprises a main gas flow path for the gas turbine engine;
a casing, a fairing disposed within the casing and connected to the seal carrier, and a probe extending through the casing, the seal cap, the seal element, and the seal carrier into the second cavity;
a first surface of the seal element defines a portion of the first cavity, and a second surface of the seal element defines a portion of the second cavity;
the second surface of the seal element contacts an inner surface of the component that defines the pocket;
the inner surface of the component abuts the seal element in a generally radial direction but is free to slide generally circumferentially or axially with respect to a centerline axis of the gas turbine engine;
the component includes a depression that forms a portion of the pocket; and
the seal cap is adapted to be joined with the component and in part cover the pocket to capture the seal element within the pocket.
An assembly for a gas turbine engine includes a carrier, a seal element, and a seal cap. The seal carrier includes a pocket with an aperture therein. The seal element is disposed within the pocket and overlies the aperture. The pocket allows the component to move relative to the seal element. The seal cap connected to the component and overlies the pocket and seal element.
The assembly of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
the seal carrier separates a first cavity of the gas turbine engine from a second cavity;
the seal carrier comprises a fairing and the second cavity comprises a main gas flow path for the gas turbine engine;
a first surface of the seal element defines a portion of the first cavity, and a second surface of the seal element forms a portion of the second cavity;
the second surface of the seal element contacts an inner surface of the seal carrier;
the inner surface of the component abuts the seal element in a generally radial direction but is free to slide generally circumferentially or axially with respect to a centerline axis of the gas turbine engine;
the seal cap is adapted to be joined with the component and in part cover the pocket to capture the seal element within the pocket; and
the seal carrier includes a depression that defines a portion of the pocket.
A turbine section for a gas turbine engine includes a casing, a fairing, a probe, a seal element, and a seal cap. The casing extends along the turbine section and the fairing is disposed within the casing to form a main gas flow path. The fairing having a pocket and an aperture therein. The probe is mounted to the casing and extends through the casing and the fairing. The seal element is disposed within the pocket and overlies the aperture in the fairing. The seal element defines an aperture that is adapted to receive the probe. The seal cap is connected to the fairing and extends around the probe and overlies the pocket and seal element.
The turbine section of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
a first surface of the seal element defines a portion of the first cavity, and wherein a second surface of the seal element forms a portion of the second cavity; and
the second surface of the seal element contacts a surface of the pocket.
Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an industrial turbine cross-section.

FIG. 2 is an exploded view of the assembly including a fairing, a seal assembly, and a frame.

FIG. 3 is a cross-section of the assembly including the fairing and the frame with an embodiment of the seal assembly and a probe, arranged together.

FIG. 4 is a cross-sectional view of one embodiment of the seal assembly with a pocket and seal cap.

FIG. 5 is a cross-sectional view of another embodiment of the seal assembly with the seal cap connected to a seal carrier.

Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples.

DETAILED DESCRIPTION

The specification discloses the use of a seal cap and pocket arrangement to retain a slider seal element. In particular, a component that receives the slider seal element is formed to define the pocket. In one exemplary embodiment, the component comprises a fairing. In another exemplary embodiment, the component comprises a seal carrier. The slider seal element resides within the pocket while sealing a shaft of a probe but allowing a fairing to move relative to the probe and slider seal element. The seal cap is adapted to be joined with the component and in part cover the pocket, thus capturing the seal element within the pocket. The arrangement described eliminates the need for a C-clip or fastener. By eliminating the need for C-clip or fastener to achieve sealing, close tolerance machining need not be used providing a number of benefits, including in some aspects a reduction in the number of parts, cost, or the weight of the gas turbine engine.
An exemplary industrial gas turbine engine 10 is circumferentially disposed about a central, longitudinal axis or axial engine centerline axis 12 as illustrated in FIG. 1. The engine 10 includes in series order from front to rear, low and high pressure compressor sections 16 and 18, a central combustor section 20 and high and low pressure turbine sections 22 and 24. In some examples, a free turbine section 26 is disposed aft of the low pressure turbine 24. Although illustrated with reference to an industrial gas turbine engine, this application also extends to aero engines with a fan or gear driven fan, and engines with more or fewer sections than illustrated.
In gas turbines, incoming ambient air 30 becomes pressurized air 32 in the compressors 16 and 18. Fuel mixes with the pressurized air 32 in the combustor section 20, where it is burned to produce combustion gases 34 that expand as they flow through turbine sections 22, 24 and power turbine 26. Turbine sections 22 and 24 drive high and low pressure rotor shafts 36 and 38 respectively, which rotate in response to the combustion products and thus the attached compressor sections 18, 16. Free turbine section 26 may, for example, drive an electrical generator, pump, or gearbox (not shown).
It is understood that FIG. 1 provides a basic understanding and overview of the various sections and the basic operation of an industrial gas turbine engine 10. The present application is applicable to all types of gas turbine engines, including those with aerospace applications.
FIG. 2 shows an exploded view of assembly 40. Assembly 40 includes frame 42, embossment 44, and fairing 46. Frame 42 includes outer radial casing 48, inner radial casing 50, and struts 52. Fairing 46 includes outer radial platform 54, inner radial platform 56, strut liners 58, and seal assembly 60.
Frame 42 comprises a stator component of gas turbine engine 10 (FIG. 1) and can form portions of compressor sections 16 and 18 or turbine sections 22 and 24. Embossment 44 is a thickened portion of outer radial casing 48 that has an aperture adapted to receive probe 62 that extends into the main gas flow path of gas turbine engine 10. Fairing 46 is connected to the frame 42 when installed. Additionally, when installed fairing 46 is disposed within the frame 42 to form the main gas flow path for a portion of gas turbine engine 10. It should be understood that the embodiments of the slider seal are provided in relation to a specific embodiment of frame 42, in particular a frame that comprises a low pressure turbine exhaust case, but the slider seal described is applicable to other gas turbine sections and elements including stator vane components.
As illustrated in FIG. 2, outer radial casing 48 of frame 42 is conically shaped and forms a portion of the casing of gas turbine engine 10 (FIG. 1), for example, in high pressure turbine section 22. Inner radial casing 50 is disposed generally radially inward of outer radial casing 48 and is connected thereto by struts 52.
Fairing 46 is adapted to be disposed within frame 42 between outer radial casing 48 and inner radial casing 50. Outer radial platform 54 of fairing 46 has a generally conical shape. Similarly, inner radial platform 56 has a generally conical shape. Inner radial platform 56 is spaced from outer radial platform 54 by strut liners 58. Strut liners 58 are adapted to be disposed around struts 52 of frame 42 when fairing 46 is assembled on frame 42. As discussed previously, outer radial platform 54, inner radial platform 56, and strut liners 58, form the main gas flow path for a portion of gas turbine engine 10 when assembled.
Seal assembly 60 is formed on fairing 46 and seals frame 42 and other components from the main gas flow path while allowing probe 62 to extend into the main gas flow path as illustrated in FIG. 3.
FIG. 3 shows a cross-section of assembly 40 with fairing 46 installed within frame 42. FIG. 3 refers to enlargements of embodiments of seal assembly, which are subsequently shown in FIGS. 4 and 5. Assembly 40 includes embossment 44, outer radial casing 48, inner radial casing 50, struts 52 (only one is shown in FIG. 3), outer radial platform 54, inner radial platform 56, strut liners 58, and seal assembly 60, and probe 62.
In FIG. 3, outer radial casing 48 abuts and is affixed to a second outer radial casing 49 of another module of gas turbine engine 10 (FIG. 1). Probe 62 is attached to and extends through embossment 44 of outer radial casing 48. As shown, probe 62 can be attached to embossment 44 by fasteners. Probe 62 extends through outer radial casing 48 and is received by and extends through seal assembly 60 in fairing 46. Probe 62 extends into the main gas flow path defined by fairing 46 and can be used to measure attributes such as the temperature or pressure of combustion gases 34 passing along the main gas flow path. In one aspect, further described in U.S. Pat. Nos. 4,433,584, 4,605,315 and 4,765,751, which are incorporated herein by reference, probe 62 includes a temperature sensing element, characterized by a tube (not shown) having a passage communicating the main gas flow path. In particular, probe 62 is designed to provide a fixed stagnation point at the throat of the inlet of the tube which provides satisfactory indication of temperature throughout the operating envelope of the engine. The temperature sensor monitors temperature condition and relays a signal when either the temperature exceeds a predetermined limit or the rate of temperature change is at an undesirable value. As used herein, probe 62 additionally encompasses a boroscope plug that is removable from frame 42 to allow a boroscope to be inserted to visually inspect components within gas turbine engine 10 for wear and/or damage.
FIG. 4 is an enlarged cross-sectional view from FIG. 3 and shows a cross-sectional view of one embodiment of seal assembly 60 with probe 62 inserted therein. Probe 62 includes shaft 64. Seal assembly 60 includes seal cap 66, seal element 68, depression 70, and pocket 72. Outer radial platform 54 of fairing 46 (FIG. 3) includes inner radial surface 74A. Depression 70 includes inner surface 76A and aperture 78. Seal cap 66 includes aperture 80.
In the embodiment of FIG. 4, depression 70 comprises a recessed area of outer radial platform 54. Together, depression 70 and seal cap 66 define pocket 72 with seal cap 66 sized to overlay pocket 72 and depression 70 forming the base of pocket 72. Seal cap 66 can be welded brazed, riveted, or otherwise affixed to outer radial platform 54 about depression 70. Depression 70 is sized larger than seal element 68 such that seal cap 66 overlays seal element 68 and does not make contact therewith in the embodiment shown in FIG. 4. Seal element 68 is disposed within pocket 72 between depression 70 and seal cap 66. Seal element 68 material is selected based upon operational criteria such as temperature, pressure, weight, wearability, and cost. Materials can range from titanium to cobalt alloys to composites.
Due to the size of depression 70 and seal cap 66, pocket 72 comprises a larger volume than seal element 68 allowing outer radial platform 54 with degrees of freedom to move relative to seal element 68 and probe 62. Seal element 68 rests upon an outer surface 76B of depression 70 and is disposed around shaft 64 to create a seal between first cavity 84 (such as the main gas flow path) and second cavity 84.
Depression 70 is formed in outer platform 54 by stamping, embossing, and machining, or other means. Inner radial surface 76A of depression 70 is disposed radially inward of inner radial surface 74A of outer radial platform 54 with respect to the engine centerline axis 12 (FIG. 1).
Outer platform 54 separates first cavity 82 from second cavity 84 (comprising main gas flow path in the embodiment shown). Outer surface 68B of the seal element 68 is covered in part by seal cap 66 within pocket 72. Seal cap 66 has aperture 80 formed therein. Aperture 80 in seal cap 66 allows outer surface 68B of seal element 68 to define a portion of first cavity 82. Similarly, inner surface 68A of the seal element 68 is contacted in part by outer surface 76B of depression 70 within pocket 72. Depression 70 has aperture 78 formed therein. Aperture 78 in depression 70 allows inner surface 68A of seal element 68 to define a portion of second cavity 84.
A pressure differential between first cavity 82 and second cavity 84 causes the inner surface 68A of seal element 68 to be forced into contact with outer surface 76B of depression 70. The contact between the inner surface 68A of seal element 68 and the outer surface 76B of depression 70 (along with contact between seal element 68 and shaft 64) maintains the seal between first cavity 82 and second cavity 84.
Seal cap 66 and depression 70 act to allow outer radial platform 54 to translate relative to probe 62 and seal element 68. In particular, apertures 78 and 80 allow outer radial platform 54 to translate for a limited distance relative to seal element 68 and probe 62. Translation can occur because pocket 72 has a volume in excess of a volume of seal element 68. In one embodiment, seal element 68 is sized to be spaced from seal cap 66. Thus, seal element 68 is fixed within pocket 72 and outer surface 76B is free to slide relative to seal element 68. However, seal element 68 remains in contact with the outer surface 76B of depression 70 as well as shaft 64 to maintain a seal. In other embodiments, seal element 68 may contact seal cap 66 but depression 70 and seal cap 66 would still slide relative to seal element 68.
FIG. 5 is an enlarged cross-sectional view from FIG. 3 and shows a cross-sectional view of second embodiment of seal assembly 160 with probe 62 inserted therein. Probe 62 includes shaft 64. Seal assembly 160 includes seal cap 166, seal element 68, seal carrier 170, and pocket 172. Fairing 54 includes inner radial surface 74A. Seal carrier 170 includes inner surface 176A and aperture 178. Seal cap 166 includes aperture 180.
Together, seal carrier 170 and seal cap 166 define pocket 172 with seal cap 166 sized to overlay pocket 172 and seal carrier 170 forming the base of pocket 172. Seal cap 166 can be welded brazed, riveted, or otherwise affixed to seal carrier 170 about pocket 172. Seal carrier 170 defines pocket 172 which is sized larger than seal element 68 such that seal cap 166 overlays seal element 68 and does not make contact therewith. Seal element 68 is disposed within pocket 172 between seal carrier 170 and seal cap 66. Seal element 68 material is selected based upon operational criteria such as temperature, pressure, weight, wearability, and cost. Materials can range from titanium to cobalt alloys to composites.
Due to the size of seal carrier 170 and seal cap 166, pocket 172 comprises a larger volume than seal element 68 both circumferentially, axially, as well as radially. This allows outer radial platform 54 with degrees of freedom to move relative to seal element 68 and probe 62. Seal element 68 rests upon a recessed surface 176B of seal carrier 170 and is disposed around shaft 64 to create a seal between first cavity 82 (such as the main gas flow path) and second cavity 84.
As illustrated in FIG. 5, seal carrier 170 comprises a separate component from outer radial platform 154. Seal carrier 170 is affixed to outer radial platform 154 by welding but in other embodiments seal carrier can be connected thereto by other means such as brazing. In other embodiments, seal carrier 170 can be formed from outer radial platform by stamping, embossing, and/or machining, or other methods.
As seal carrier 170 extends outward of outer radial platform 154 in the embodiment shown in FIG. 5, inner surface 174 of outer platform 154 is disposed radially flush with inner surface 176A of seal carrier 170.
Outer platform 54 and seal carrier 170 separate first cavity 82 from second cavity 84 (comprising main gas flow path in the embodiment shown). Outer surface 68B of the seal element 68 is covered in part by seal cap 166 within pocket 172. Seal cap 166 has aperture 180 formed therein. Aperture 180 in seal cap 166 allows outer surface 68B of seal element 68 to define a portion of first cavity 82. Similarly, inner surface 68A of the seal element 68 is contacted in part by recessed surface 176B of seal carrier 170 within pocket 172. Seal carrier 170 has aperture 178 formed therein. Aperture 178 in seal carrier 170 allows inner surface 68A of seal element 68 to define a portion of second cavity 84.
A pressure differential between first cavity 82 and second cavity 84 causes the inner surface 68A of seal element 68 to be forced into contact with outer surface 176B of seal carrier 170. The contact between the inner surface 68A of seal element 68 and the recessed surface 176B of seal carrier 170 (along with contact between seal element 68 and shaft 64) maintains the seal between first cavity 82 and second cavity 84.
Seal cap 166 and seal carrier 170 act to allow outer radial platform 54 to translate relative to probe 62 and seal element 68. In particular, apertures 78 and 80 allow outer radial platform 54 to translate for a limited distance relative to seal element 68 and probe 62. Translation can occur because pocket 172 has a volume in excess of a volume of seal element 68. In one embodiment, seal element 68 is sized to be spaced from seal cap 66. Thus, seal element 68 is fixed within pocket 172 and recessed surface 176B is free to slide relative to seal element 68. However, seal element 68 remains in contact with the recessed surface 176B of seal carrier 170 as well as shaft 64 to maintain a seal. In other embodiments, seal element 68 may contact seal cap 66 but seal carrier 170 and seal cap 66 would still slide relative to seal element 68.
The specification discloses the use of a seal cap and pocket arrangement to retain a slider seal element. In particular, the component that receives the slider seal element is formed to create the pocket. The slider seal element resides within the pocket while sealing a shaft of a probe but allowing a fairing to move relative to the probe and slider seal element. The arrangement described eliminates the need for a C-clip or fastener. By eliminating the need for C-clip or fastener to achieve sealing, close tolerance machining need not be used and the number of parts and the weight of the gas turbine engine can be reduced.
While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. An assembly for a gas turbine engine, comprising:

a seal element;

a component defining a pocket adapted to accept the seal element, wherein the pocket allows for sliding movement of the component relative to the seal element; and

a seal cap overlying the pocket and the seal element.

2. The assembly of claim 1, wherein the component comprises a seal carrier, and the pocket is disposed in the seal carrier, and wherein the seal carrier separates a first cavity of the gas turbine engine from a second cavity of the gas turbine engine.

3. The assembly of claim 2, wherein the second cavity comprises a main gas flow path for the gas turbine engine.

4. The assembly of claim 3, further comprising:

a casing;

a fairing disposed within the casing and connected to the seal carrier; and

a probe extending through the casing, the seal cap, the seal element, and the seal carrier into the second cavity.

5. The assembly of claim 2, wherein a first surface of the seal element defines a portion of the first cavity, and wherein a second surface of the seal element defines a portion of the second cavity.

6. The assembly of claim 5, wherein the second surface of the seal element contacts an inner surface of the component that defines the pocket.

7. The assembly of claim 6, wherein the inner surface of the component abuts the seal element in a generally radial direction but is free to slide generally circumferentially or axially with respect to a centerline axis of the gas turbine engine.

8. The assembly of claim 1, wherein the component includes a depression that forms a portion of the pocket.

9. The assembly of claim 1, wherein the seal cap is adapted to be joined with the component and in part cover the pocket to capture the seal element within the pocket.

10. An assembly for a gas turbine engine, comprising:

a seal carrier including a pocket with an aperture therein;

a seal element disposed within the pocket and overlying the aperture, wherein the pocket allows the component to move relative to the seal element; and

a seal cap connected to the component and overlaying the pocket and seal element.

11. The assembly of claim 10, wherein the seal carrier separates a first cavity of the gas turbine engine from a second cavity.

12. The assembly of claim 11, wherein the seal carrier comprises a fairing and the second cavity comprises a main gas flow path for the gas turbine engine.

13. The assembly of claim 11, wherein a first surface of the seal element defines a portion of the first cavity, and wherein a second surface of the seal element forms a portion of the second cavity.

14. The assembly of claim 13, wherein the second surface of the seal element contacts an inner surface of the seal carrier.

15. The assembly of claim 14, wherein the inner surface of the component abuts the seal element in a generally radial direction but is free to slide generally circumferentially or axially with respect to a centerline axis of the gas turbine engine.

16. The assembly of claim 10, wherein the seal cap is adapted to be joined with the component and in part cover the pocket to capture the seal element within the pocket.

17. The assembly of claim 10, wherein the seal carrier includes a depression that defines a portion of the pocket.

18. A turbine section for a gas turbine engine, comprising:

a casing extending along the turbine section;

a fairing disposed within the casing to form a main gas flow path, the fairing having a pocket and an aperture therein;

a probe mounted to the casing and extending through the casing and the fairing;

a seal element disposed within the pocket and overlying the aperture in the fairing, wherein the seal element defines an aperture that is adapted to receive the probe; and

a seal cap connected to the fairing and extending around the probe and overlaying the pocket and seal element.

19. The turbine section of claim 18, wherein a first surface of the seal element defines a portion of the first cavity, and wherein a second surface of the seal element forms a portion of the second cavity.

20. The turbine section of claim 19, wherein the second surface of the seal element contacts a surface of the pocket.