Egress seal fitting

An egress seal fitting for a bulkhead penetration may comprise a housing, a driver configured to couple to the housing and define a cavity within the housing, and a seal member configured to be disposed within the cavity of the housing, wherein the driver is configured to pass a cable through the housing and apply pressure to the seal member.

FIELD

The disclosure relates generally to protective structures for aircraft cables and cable pathways, and particularly to pressure seal fittings for pressure compartments.

BACKGROUND

Aircraft cables such as gas turbine engine control and sensor cables may pass through various pressure compartments such as, for example, a pressure bulkhead or a compressor casing. Pressure losses at the penetration site may tend to degrade aircraft performance and benefit of a pressure seal fitting about the cable penetration. In industries and applications where weight and packaging is a significant design factor, such as in the aircraft industry fittings for cable penetration tend to be bulky or comprise a relatively high part count included many seal members. Ideally, a seal fitting will be comparatively light weight and compact.

SUMMARY

In various embodiments the present disclosure provides an egress seal fitting for a bulkhead penetration, comprising a housing, a driver configured to couple to the housing and define a cavity within the housing, and a seal member configured to be disposed within the cavity of the housing, wherein the driver is configured to pass a cable through the housing and apply pressure to the seal member.

In various embodiments, the housing comprises an annular cylindrical structure extending between a flanged portion and a base portion. In various embodiments, the housing comprises a first housing half and a second housing half. In various embodiments, wherein each of the first housing half and the second housing half comprise a corresponding externally threaded surface and a corresponding internally threaded surface. In various embodiments, the internally threaded surface of the first housing half and the internally threaded surface of the second housing half each extend only partially over the internal diameter of the annular cylindrical structure to define a driver stop. In various embodiments, the driver is configured to apply axial pressure to the seal member and expand the seal member radially between the housing and the cable. In various embodiments, the driver comprises an annular cylindrical drive portion and a head. In various embodiments, the drive portion comprises an externally threaded surface. In various embodiments, the driver comprises a first driver half and a second driver half. In various embodiments, the housing comprises an elongate base portion including a first driver cavity and a second driver cavity.

In various embodiments, the present disclosure provides a gas turbine engine, comprising a compressor section configured to compress a gas, a combustor section aft of the compressor section and configured to combust the gas, a turbine section aft of the combustor section and configured to extract work from the gas, a pressure bulkhead dividing a first pressure compartment from a second pressure compartment, wherein a pressure differential exists between the first pressure compartment and the second pressure compartment, and an egress seal fitting coupled to a penetration of the pressure bulkhead, comprising a housing, a driver coupled to the housing and defining a cavity within the housing, and a seal member disposed within the cavity of the housing and compressed by the driver, wherein the driver is configured to pass a penetrating member through the housing and expand the seal member radially between the housing and the penetrating member.

In various embodiments, the housing comprises an annular cylindrical structure extending between a flanged portion and a base portion. In various embodiments, the housing comprises a first housing half and a second housing half. In various embodiments, wherein each of the first housing half and the second housing half comprise a corresponding externally threaded surface and a corresponding internally threaded surface. In various embodiments, the internally threaded surface of the first housing half and the internally threaded surface of the second housing half each extend only partially over the internal diameter of the annular cylindrical structure to define a driver stop. In various embodiments, the driver comprises an annular cylindrical drive portion and a head. In various embodiments, the drive portion comprises an externally threaded surface. In various embodiments, the driver comprises a first driver half and a second driver half. In various embodiments, the housing comprises an elongate base portion including a first driver cavity and a second driver cavity.

In various embodiments, the present disclosure provides a method of sealing a pressure bulkhead penetration, the method comprising disposing a housing about a penetrating member passing through the pressure bulkhead penetration, coupling the housing to the pressure bulkhead penetration, disposing a seal member within a cavity of the housing, disposing a driver about the penetrating member and coupling the driver to the housing, and applying pressure to the seal member via the driver and expanding the seal member radially between the housing and the penetrating member in response to the pressure.

DETAILED DESCRIPTION

In various embodiments and with reference toFIG. 1, a gas turbine engine20is provided. Gas turbine engine20may be a two-spool turbofan that generally incorporates a fan section22, a compressor section24, a combustor section26and a turbine section28. In operation, fan section22can drive air along a bypass flow-path B while compressor section24can drive air for compression and communication into combustor section26then expansion through turbine section28. Although depicted as a turbofan gas turbine engine20herein, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines including turbojet engines, a low-bypass turbofans, a high bypass turbofans, or any other gas turbine known to those skilled in the art.

Gas turbine engine20may generally comprise a low speed spool30and a high speed spool32mounted for rotation about an engine central longitudinal axis A-A′ relative to an engine static structure36via one or more bearing systems38(shown as bearing system38-1and bearing system38-2). It should be understood that various bearing systems38at various locations may alternatively or additionally be provided, including for example, bearing system38, bearing system38-1, and bearing system38-2.

Low speed spool30may generally comprise an inner shaft40that interconnects a fan42, a low pressure (or first) compressor section44(also referred to a low pressure compressor) and a low pressure (or first) turbine section46. Inner shaft40may be connected to fan42through a geared architecture48that can drive fan42at a lower speed than low speed spool30. Geared architecture48may comprise a gear assembly60enclosed within a gear housing62. Gear assembly60couples inner shaft40to a rotating fan structure. High speed spool32may comprise an outer shaft50that interconnects a high pressure compressor (“HPC”)52(e.g., a second compressor section) and high pressure (or second) turbine section54. A combustor56may be located between HPC52and high pressure turbine54. A mid-turbine frame57of engine static structure36may be located generally between high pressure turbine54and low pressure turbine46. Mid-turbine frame57may support one or more bearing systems38in turbine section28. Inner shaft40and outer shaft50may be concentric and rotate via bearing systems38about the engine central longitudinal axis A-A′, which is collinear with their longitudinal axes. As used herein, a “high pressure” compressor or turbine experiences a higher pressure than a corresponding “low pressure” compressor or turbine.

The core airflow C may be compressed by low pressure compressor44then HPC52, mixed and burned with fuel in combustor56, then expanded over high pressure turbine54and low pressure turbine46. Mid-turbine frame57includes airfoils59which are in the core airflow path. Low pressure turbine46, and high pressure turbine54rotationally drive the respective low speed spool30and high speed spool32in response to the expansion.

Gas turbine engine20may be, for example, a high-bypass geared aircraft engine. In various embodiments, the bypass ratio of gas turbine engine20may be greater than about six (6). In various embodiments, the bypass ratio of gas turbine engine20may be greater than ten (10). In various embodiments, geared architecture48may be an epicyclic gear train, such as a star gear system (sun gear in meshing engagement with a plurality of star gears supported by a carrier and in meshing engagement with a ring gear) or other gear system. Geared architecture48may have a gear reduction ratio of greater than about 2.3 and low pressure turbine46may have a pressure ratio that is greater than about 5. In various embodiments, the bypass ratio of gas turbine engine20is greater than about ten (10:1). In various embodiments, the diameter of fan42may be significantly larger than that of the low pressure compressor44, and the low pressure turbine46may have a pressure ratio that is greater than about (5:1). Low pressure turbine46pressure ratio may be measured prior to inlet of low pressure turbine46as related to the pressure at the outlet of low pressure turbine46prior to an exhaust nozzle. It should be understood, however, that the above parameters are exemplary of various embodiments of a suitable geared architecture engine and that the present disclosure contemplates other gas turbine engines including direct drive turbofans.

In various embodiments, the next generation of turbofan engines may be designed for higher efficiency which is associated with higher pressure ratios and higher temperatures in the HPC52. These higher operating temperatures and pressure ratios may create operating environments that may cause thermal loads that are higher than the thermal loads encountered in conventional turbofan engines, which may shorten the operational life of current components.

In various embodiments, HPC52may comprise alternating rows of rotating rotors and stationary stators. Stators may have a cantilevered configuration or a shrouded configuration. More specifically, a stator may comprise a stator vane, a casing support and a hub support. In this regard, a stator vane may be supported along an outer diameter by a casing support and along an inner diameter by a hub support. In contrast, a cantilevered stator may comprise a stator vane that is only retained and/or supported at the casing (e.g., along an outer diameter).

In various embodiments, rotors may be configured to compress and spin a fluid flow. Stators may be configured to receive and straighten the fluid flow. In operation, the fluid flow discharged from the trailing edge of stators may be straightened (e.g., the flow may be directed in a substantially parallel path to the centerline of the engine and/or HPC) to increase and/or improve the efficiency of the engine and, more specifically, to achieve maximum and/or near maximum compression and efficiency when the straightened air is compressed and spun by rotor64.

According to various embodiments and with reference toFIGS. 1 and 2A, an egress seal fitting200is shown in cross section through the XY-plane. Seal fitting200comprises a housing202and a driver204. Housing202is coupled to a bulkhead206, such as the HPC52case, at penetration208. In various embodiments, bulkhead206divides a low pressure compartment at a first pressure P1from a relatively high pressure compartment at a second pressure P2. In various embodiments, the pressure differential between P1and P2may be about 10,000 psi [69 Mpa] where about in this context means±10%. A penetrating member such as cable210or other penetrating member (e.g., a pipe, duct, optical fiber, etc.) penetrates the bulkhead at penetration208. In various embodiments, the housing202may comprise an annular cylindrical structure212extending between a flanged portion214and a base portion216. The driver204is coupled about the cable210and disposed within the housing202thereby defining a cavity218within the housing202proximate the base portion216.

In various embodiments and with additional references toFIGS. 2B, 2C and 2D, the housing202is separated into a first housing half202′ and a second housing half202″. Cable210is passed through penetration208of bulkhead206(arrow210′). The first housing half202′ and the second housing half202″ are inserted about the cable210into the penetration208and coupled to the bulkhead206. In various embodiments, the penetration208may be threaded and the housing202may include corresponding threads. The first housing half202′ may be coupled to the bulkhead206by a first external threaded surface220. In like regard, the second housing half202″ may be coupled to the bulkhead by a second external threaded surface222. Flanged portion214may include tool interfaces224configured to enable the housing202to receive torque from a torque tool such as, for example, a spanner wrench. In various embodiments, torque FTmay be applied at the tool interfaces224and the housing separation plane226may be configured to balance and/or distribute the torque between the halves (202′,202″) and, in this regard, the housing202may behave as a monolithic structure. For example, housing202may be formed as a monolithic structure including a kerf portion at the housing separation plane226thereby tending to impart a relatively oblate geometry to the housing202. In response to separating housing202into the halves (202′,202″), the kerf portion may be removed, tending thereby to impart a circular geometry to the housing202conducive to distributing the torque force FT.

In various embodiments, a seal member228is inserted into the cavity218and disposed about the cable210. The seal member may comprise one of a potting material (e.g, a room temperature vulcanization compound, a clay, an epoxy, etc.), an O-ring, a ferrule, and/or the like. In various embodiments, the driver204comprises an annular cylindrical drive portion230coupled to a head232. The drive portion may comprise an externally threaded surface234extending along the external diameter of the drive portion. The externally threaded surface234may be configured to engage with respective first internally threaded surface236and second internally threaded surface238of the housing halves (202′,202″). In various embodiments, each of the first internally threaded surface236and second internally threaded surface238may extend only partially over the inner diameter of the annular cylindrical structure212to define a driver stop240.

In similar fashion to housing202, the driver204may be divided into a first driver half204′ and a second driver half204″. The first driver half204′ and the second driver half204″ are inserted about the cable210into the housing202. Head232may include the tool interfaces224′ configured to enable the driver204to receive torque from a torque tool such as, for example, a spanner wrench. In various embodiments, second torque FT2may be applied at the tool interfaces224′ and the driver separation plane242may be configured to balance and/or distribute the torque between the halves (204′,204″) and, in this regard, the driver204may behave as a monolithic structure. For example, driver204may be formed as a monolithic structure including a kerf portion at the driver separation plane242thereby tending to impart a relatively oblate geometry to the driver204. In response to separating driver204into the halves (204′,204″), the kerf portion may be removed tending thereby to impart a circular geometry to the driver204conducive to distributing the second torque force FT2. In response to the second torque force FT2the driver204may apply axial (along arrow244) pressure to the seal member228tending to cause the seal member228to expand radially between the housing and the cable210. In this regard, the expansion of the seal member228in response to the axial pressure generated by the driver204tends to effect a pressure seal between the cable210and the housing202. In various embodiments, driver204may contact the driver stop240in response to the second torque force FT2and, in this regard, the pressure applied by the driver204to the seal member228may be limited to a desired pressure.

In various embodiments and with additional reference toFIGS. 3A through 3E, an egress seal fitting300is shown in various stages of assembly. Egress seal fitting300comprises features, geometries, construction, materials, manufacturing techniques, and/or internal components similar to egress seal fitting300but having a hexagonal head and flanged portion.FIG. 3Aillustrates a housing half302′ disposed about a cable310prior to insertion at a penetration308.FIG. 3Billustrates the housing302about the cable310and coupled to the bulkhead306at the penetration308.FIG. 3Cillustrates the seal member328disposed about the cable310prior to insertion into the cavity318of the housing302.FIG. 3Dillustrates a driver half304′ disposed about the cable310prior to insertion within the housing302.FIG. 3Eillustrates the driver304torqued and coupled to the housing302to generate a seal about the cable310.

In various embodiments and with additional reference toFIG. 4, a housing400for an egress seal fitting is illustrated. Housing400comprises features, geometries, construction, materials, manufacturing techniques, and/or internal components similar to housing202. Housing400differs in comprising an elongate base portion402. In various embodiments, the elongate base portion402may be a monolithic structure coupled to the bulkhead406. The elongate base portion402may comprise a plurality of driver cavities such as first driver cavity404and second driver cavity404′. Each of the driver cavities may be configured to receive a cable and couple with a driver such as, for example, driver204or driver304.

With additional reference toFIG. 5, a method500of sealing a pressure bulkhead penetration may comprise disposing a housing about a penetrating member passing through the pressure bulkhead penetration (step502). Method500includes coupling the housing to the pressure bulkhead penetration and disposing a seal member within a cavity of the housing (step504). Method500includes disposing a driver about the penetrating member and coupling the driver to the housing (step506). Method500includes applying a pressure to the seal member via the driver and expanding the seal member radially between the housing and the penetrating member in response to the pressure (step508).