Face seal carrier arrester

A face seal assembly includes a seal carrier, a seal element supported by the seal carrier, a rotating seal plate interactive with the seal element to define a face seal, and a seal arrester configured to engage the seal carrier at a predetermined amount of wear of the seal element to stop wear of the seal element.

BACKGROUND

Exemplary embodiments of the present disclosure pertain to the art of gas turbine engines, and in particular to face seal assemblies of gas turbine engines.

Gas turbine engines include face seal assemblies at various locations, such as at bearing compartments and/or to seal to rotating shafts. Low time, premature, wear of seal elements of face seal assemblies is problematic for gas turbine engine reliability and operability. Premature seal element wear can result in seal element fracture and lack of oil containment, thereby resulting in conditions such as cabin odor or smoke in the cabin.

BRIEF DESCRIPTION

In one embodiment, a face seal assembly includes a seal carrier, a seal element supported by the seal carrier, a rotating seal plate interactive with the seal element to define a face seal, and a seal arrester configured to engage the seal carrier at a predetermined amount of wear of the seal element to stop wear of the seal element.

Additionally or alternatively, in this or other embodiments a spring element is configured to urge the seal carrier and the seal element toward the seal plate.

Additionally or alternatively, in this or other embodiments the seal arrester prevents urging of the seal carrier and the seal element toward the seal plate via the spring element.

Additionally or alternatively, in this or other embodiments the assembly includes a seal support, with the seal carrier and the seal element housed in the seal support.

Additionally or alternatively, in this or other embodiments the seal arrester is secured to the seal support.

Additionally or alternatively, in this or other embodiments the seal arrester is secured via one or more of a snap fit or installed in a groove of the seal support.

Additionally or alternatively, in this or other embodiments the seal arrester includes an arrester base and an arrester arm extending from the arrester base, the arrester arm configured to engage the seal carrier.

Additionally or alternatively, in this or other embodiments contact of the seal arrester to the seal carrier completes an electrical circuit to initiate an alarm.

Additionally or alternatively, in this or other embodiments the seal arrester is contoured to improve oil circulation at the seal arrester.

Additionally or alternatively, in this or other embodiments the seal element includes a nose portion configured to engage the seal plate.

In another embodiment, a gas turbine engine includes a turbine, a rotating shaft driven by the turbine, a bearing assembly supportive of the shaft, and a face seal assembly configured to seal the bearing assembly. The face seal assembly includes a seal carrier, a seal element supported by the seal carrier, a rotating seal plate interactive with the seal element to define a face seal, and a seal arrester configured to engage the seal carrier at a predetermined amount of wear of the seal element to stop wear of the seal element.

Additionally or alternatively, in this or other embodiments a spring element is configured to urge the seal carrier and the seal element toward the seal plate.

Additionally or alternatively, in this or other embodiments the seal arrester prevents urging of the seal carrier and the seal element toward the seal plate via the spring element.

Additionally or alternatively, in this or other embodiments the assembly includes a seal support, with the seal carrier and the seal element housed in the seal support.

Additionally or alternatively, in this or other embodiments the seal arrester is secured to the seal support.

Additionally or alternatively, in this or other embodiments the seal arrester is secured via one or more of a snap fit or installed in a groove of the seal support.

Additionally or alternatively, in this or other embodiments the seal arrester includes an arrester base and an arrester arm extending from the arrester base, the arrester arm configured to engage the seal carrier.

Additionally or alternatively, in this or other embodiments contact of the seal arrester to the seal carrier completes an electrical circuit to initiate an alarm.

Additionally or alternatively, in this or other embodiments the seal arrester is contoured to improve oil circulation at the seal arrester.

Additionally or alternatively, in this or other embodiments the seal element includes a nose portion configured to engage the seal plate.

DETAILED DESCRIPTION

Referring now toFIG. 2, illustrated is an embodiment of a face seal assembly60located at a bearing assembly62. The bearing assembly62in this embodiment is located at the outer shaft50, but one skilled in the art will appreciate that the bearing assembly62and face seal assembly60may be utilized at the inner shaft40or at other rotating components of the gas turbine engine20. The face seal assembly60seals between a bearing compartment64and a buffer air cavity96.

A seal plate66is secured to and rotates with the outer shaft50. A seal element68, formed from carbon, for example, is urged toward the seal plate66to define the face seal. The seal element68is supported by a seal carrier70. In some embodiments, the seal element68and the seal carrier70are urged toward the seal plate66by a spring element72. The seal carrier70, the seal element68and the spring element72are housed in a stationary seal support74. The seal element68includes a nose portion76that during operation contacts a sealing face98of the seal plate66. As the seal plate66rotates about the engine central longitudinal axis A relative to the seal element68, the nose portion76is eroded or worn away.

Referring now toFIG. 3, to prevent over wear of the seal element68and damage to the seal element68and/or the seal carrier70, an arrester78is secured to the seal support74. When the nose portion76has completely worn away or as worn past a predetermined location, the seal carrier70contacts the arrester78. This contact prevents further travel of the seal carrier70and the seal element68, and thereby prevents further wear of the seal element68. The face seal thus transitions from a contacting face seal to a close-clearance butt gap seal.

In the embodiment ofFIG. 3, the arrester78includes an arrester base80, with an arrester arm82extending from the arrester base80toward the seal element68. The arrester base80is affixed to the seal support74, and in particular to a support arm84of the seal support74. In some embodiments a contact surface86of the arrester arm82is configured to contact the seal element68when the seal element68is worn. Further, the contact surface86is, in some embodiments, located at a same axial location as the contact surface98of the seal plate66. In one embodiment, such as inFIG. 3, the arrester arm82is curvilinear along its length to aid in circulation of oil flow in the bearing compartment64.

In another embodiment, such as shown inFIG. 4, the arrestor78is snapped or press fit to the seal support74. Alternatively, the arrestor78may be secured to the seal support74by, for example, a threaded connection. Referring now toFIG. 5, the arrestor78may be a retaining ring90disposed in a retaining groove92of the seal support74, and which extends radially inwardly toward the seal element68. In another embodiment, illustrated inFIG. 6, the seal carrier70includes a carrier flange100extending radially outwardly from the seal carrier70, radially inboard of the arrestor78. As the seal element68wears, the carrier flange100translates axially toward the arrestor arm82, which then limits travel of the seal carrier70by acting as an axial stop. This configuration increases radial engagement of the arrestor80to the seal carrier70and allows the arrestor arm82to be positioned axially distant from the seal plate66.

Referring again toFIG. 3, the arrester78may be configured to provide an alarm, for example in a cockpit or other location. In such embodiments, the seal carrier70is utilized to complete an electrical circuit, when contact between the seal carrier70and the arrester78is initiated. When the circuit is completed, an alarm indicator94such as a light or audible alarm is triggered.

Use of the arrester78stops seal element68wear at a selected level when the seal carrier70contacts the arrester78, preventing more catastrophic failure of the seal assembly. Additionally, the arrester78may provide an active means for detection of seal element68wear, via the alarm indicator94.