Patent Description:
Typical double wall pipes in gas turbine engines employ couplings that use high cost flanges that are associated with expensive and inefficient processing. These flanges may also be heavy and include structures that may be optimized. Attachment of the flanges may involve several processing steps including, for example, welding, swaging, and brazing. Moreover, the processing costs account for the majority of the fabrication costs of doubled wall pipe configurations.

<CIT> discloses a fuel pipe arrangement where a fuel pipe is enclosed by a slightly larger diameter second pipe such that any fuel leaked from the fuel pipe is contained by the second pipe.

<CIT> discloses dielectric isolators for use in aircraft fuel systems.

<CIT> discloses a double wall tube adapter and joint.

<CIT> discloses a fixing system of a flame pipe or liner.

<CIT> discloses a connected structure of vacuum double pipes and a joint configured to connect the vacuum double pipes.

According to an aspect of the present invention, there is provided a double wall pipe assembly as claimed in claim <NUM>.

Some embodiments of this aspect of the invention are provided in claims dependent from claim <NUM>.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice these embodiments, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with the present disclosure and the teachings herein. Thus, the detailed description herein is presented for purposes of illustration only and not for providing limitations on the scope of the disclosure. For example, the steps recited in any of the methods or process descriptions may be executed in any order and are not limited to the order presented. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Moreover, surface shading lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials.

Referring to <FIG>, a gas turbine engine <NUM> (such as a turbofan gas turbine engine) is illustrated according to various embodiments. Gas turbine engine <NUM> is disposed about axial centerline axis A-A', which may also be referred to as axis of rotation A-A'. Gas turbine engine <NUM> may comprise a fan <NUM>, compressor sections <NUM> and <NUM>, a combustion section <NUM>, and turbine sections <NUM>, <NUM>. Air compressed in the compressor sections <NUM>, <NUM> may be mixed with fuel and burned in combustion section <NUM> and expanded across the turbine sections <NUM>, <NUM>. The turbine sections <NUM>, <NUM> may include high pressure rotors and low pressure rotors, which rotate in response to the expansion. The turbine sections <NUM>, <NUM> may comprise alternating rows of rotary airfoils or blades and static airfoils or vanes. Cooling air may be supplied to the turbine sections <NUM>, <NUM> from the compressor sections <NUM>, <NUM>. A plurality of bearings <NUM> may support spools in the gas turbine engine <NUM>. <FIG> provides a general understanding of the sections in a gas turbine engine, and is not intended to limit the disclosure. The present disclosure may extend to all types of turbine engines, including turbofan gas turbine engines and turbojet engines, for all types of applications.

The forward-aft positions of gas turbine engine <NUM> lie along axis of rotation A-A'. For example, fan <NUM> may be referred to as forward of turbine section <NUM> and turbine section <NUM> may be referred to as aft of fan <NUM>. Typically, during operation of gas turbine engine <NUM>, air flows from forward to aft, for example, from fan <NUM> to turbine section <NUM>. As air flows from fan <NUM> to the more aft components of gas turbine engine <NUM>, axis of rotation A-A' may also generally define the direction of the air stream flow.

In various embodiments, double wall pipes may be employed to transport fluids, and particularly, flammable fluids, through aircraft structures and in aircraft volumes (e.g., along the engine cage). These double wall pipes typically are associated with expensive and resource intensive manufacturing processes. For example, typical double wall pipe assemblies may employ orbital welds, swaging, and brazing of flanges. However, these swaging and brazing processes may be expensive and timeconsuming.

The double wall pipes defined herein are described in the context of use in aerospace applications, and in particular, in the context of use in conjunction with gas turbine engines including, for example, gas turbine engine <NUM> as shown in <FIG> and <FIG>. However, the double wall pipe configurations described herein may be used in any suitable double wall pipe application and/or environment. As such, the description of the double wall pipes in the context of a gas turbine engine is for illustrative purposes only and is not intended to limit the application.

In various embodiments and with reference to <FIG> and <FIG>, double wall pipe <NUM> may run along a portion of or along the outside perimeter of case <NUM>. Case <NUM> may be any suitable portion of the case surrounding engine components of gas turbine engine <NUM>. For example, case <NUM> may be the case surrounding all or a portion of compressor section <NUM>, compressor section <NUM>, combustor <NUM>, turbine section <NUM>, and/or turbine section <NUM>. Moreover, case <NUM> may cover one or more of the components that make up gas turbine engine <NUM>. Similarly, double wall pipe <NUM> may move fluid from one section of gas turbine engine <NUM> to another section of gas turbine engine <NUM> along and outside case <NUM>.

In various embodiments, gas turbine engine <NUM> and/or case <NUM> may comprise one or more double wall pipes <NUM> including, for example, double wall pipe <NUM>-<NUM>, double wall pipe <NUM>-<NUM>, and/or double wall pipe <NUM>-<NUM> in <FIG>. Double wall pipe <NUM> may include any suitable flange coupling and/or fitting. For example double wall pipe <NUM>-<NUM> may comprise a fitting <NUM> that is configured to interface with case <NUM>.

With reference to <FIG>, double wall pipe <NUM> may comprise a first pipe <NUM> and a second pipe <NUM>. First pipe <NUM> and second pipe <NUM> may be operatively coupled to first fitting <NUM> (e.g., by orbital welded). Second pipe <NUM> sleeves over and/or is installed over first pipe <NUM>. Second pipe <NUM> may be operably coupled to first fitting <NUM> (e.g., by orbital welding). In this regard, double wall pipe <NUM> may comprise a chamber <NUM> and/or a channel between first pipe <NUM> and second pipe <NUM>. Any fluid leaked from first pipe <NUM> may be contained in and/or conducted through the chamber <NUM> to a suitable drainage point.

In various embodiments, piloted flange assembly <NUM> may comprise a first piloted flange <NUM> and a second piloted flange <NUM>. Piloted flange assembly <NUM> may be installable on double wall pipe <NUM>. In this regard, piloted flange assembly <NUM> may be operatively coupled to double wall pipe <NUM> in any suitable fashion including, for example, welding, swaging, brazing and/or the like.

In various embodiments and in response to first pipe <NUM> and second pipe <NUM> are operatively coupled to first fitting <NUM>, a first piloted flange <NUM> may be installed on first pipe <NUM>. First piloted flange <NUM> is operatively coupled to first pipe <NUM>. For example, first piloted flange <NUM> may be coupled to first pipe <NUM> with an orbital weld. Second piloted flange <NUM> may then be sleeved over first piloted flange <NUM> and first pipe <NUM> and operatively coupled to second pipe <NUM>. In this regard, second piloted flange <NUM> may be coupled to second pipe <NUM> with an orbital welded. Piloted flange assembly <NUM> may be installable in a coupling to join segments of double wall pipes <NUM>.

In various embodiments and with reference to <FIG> and <FIG>, coupling <NUM> may be configured to receive the piloted flange assembly <NUM>. Coupling <NUM> defines one or more minor diameter receivable slots <NUM>, which are shown minor diameter receivable slots <NUM>-<NUM> and minor diameter receivable slot <NUM>-<NUM> in <FIG>. Minor diameter receivable slot <NUM> may be defined and/or configured to receive first piloted flange <NUM>. Coupling <NUM> also comprises and/or defines one or more major diameter receivable slots <NUM>, which are shown major diameter receivable slot <NUM>-<NUM> and major diameter receivable slot <NUM>-<NUM>. Major diameter receivable slot <NUM> is configured to receive and/or support second piloted flange <NUM>.

In various embodiments, coupling <NUM> may comprise a flange <NUM>. Flange <NUM> may be configured to support and/or attach coupling <NUM> to a support structure (e.g., case <NUM> as shown in <FIG> and <FIG>). Coupling <NUM> also comprises one or more passageways <NUM> operatively configured to conduct fluid between a first major diameter receivable slot <NUM>-<NUM> to a second major diameter receivable slot <NUM>-<NUM>.

With reference to <FIG> and <FIG>, coupling <NUM> defines a plurality of passages <NUM> which are shown as passage <NUM>-<NUM>, passage <NUM>-<NUM>, passage <NUM>-<NUM>, passage <NUM>-<NUM>, passage <NUM>-<NUM>, and/or passage <NUM>-<NUM> in <FIG>. In this regard coupling <NUM> may include any suitable number of passages. Passage <NUM> is configured to conduct a fluid from in the volume defined between the first pipe and the second pipe of a doubled wall pipe assembly. In this regard, fluid leaked from the first pipe may be captured and contained in the volume created or defined between the first pipe and the second pipe. This fluid may be conducted across one or more couplings <NUM> so that it may be drained at a suitable drain point.

In various embodiments, minor diameter receivable slot <NUM> may be isolated from major diameter receivable slot <NUM>. In this regard, fluid conducted through an inner pipe received in minor diameter receivable slot <NUM> may be isolated from the volume defined between an inner pipe (e.g., first pipe <NUM> as shown in <FIG>) and an outer pipe (e.g., second pipe <NUM> as shown in <FIG>), where the outer pipe is received in major diameter receivable slot <NUM>.

In various embodiments, coupling <NUM> may also comprise flange <NUM>. Flange <NUM> may be any suitable structure, including an integrally formed flange with one or more attachment points such as, for example, attachment point <NUM>-<NUM> and/or attachment point <NUM>-<NUM>, as shown in <FIG>. Flange <NUM> may also be operably coupled to a bracket <NUM>. Bracket <NUM> may be configured to engage and/or hold coupling <NUM> as shown in <FIG>. Flange <NUM> may be installable on any suitable structure including, for example, a gas turbine engine case (e.g., case <NUM> as shown in <FIG> and <FIG>).

With reference to <FIG>, double wall pipe <NUM> is receivable in coupling <NUM>. More specifically, flange assembly <NUM> of double wall pipe <NUM> is receivable in coupling <NUM>. In this regard, first pipe <NUM> comprises and/or is coupled to first piloted flange <NUM>. First piloted flange <NUM> and first pipe <NUM> may is received in and/or installable in minor diameter receivable slot <NUM> of coupling <NUM>. Second pipe <NUM> comprises and/or is coupled to second piloted flange <NUM>. Second piloted flange <NUM> and second pipe <NUM> are received by and/or may be installable in major diameter receivable slot <NUM> of coupling <NUM>.

In various embodiments, first piloted flange <NUM> may comprise a channel and/or slot capable of receiving and retaining a seal <NUM>. Seal <NUM> is installed on first piloted flange <NUM> and is compressed in response to first piloted flange <NUM> being installed in minor diameter receivable slot <NUM>. In this regard, seal <NUM> is capable of and/or configured to retain first piloted flange <NUM> within minor diameter receivable slot <NUM>. Similarly, second piloted flange <NUM> may include a channel and/or slot that is configured to receive a seal <NUM>. Seal <NUM> is installed on second piloted flange <NUM>. In response to being installed in major diameter receivable slot <NUM>, seal <NUM> compresses and retains second piloted flange <NUM> and coupling <NUM>.

In various embodiments, double wall pipe <NUM> and/or flange assembly <NUM> may further include a collar <NUM>. Collar <NUM> may be slidably installed on double wall pipe <NUM> and may be configured to operatively couple to coupling <NUM>. Collar <NUM> may be a threaded collar. In this regard, collar <NUM> may be configured to operatively couple to and/or threadably engage coupling <NUM> to retain flange assembly <NUM> and/or double wall pipe <NUM> in coupling <NUM>. Collar <NUM> may also be secured and/or operatively coupled to coupling <NUM> with one or more fasteners such as, for example screws, set screws and/or any other suitable mechanical and/or chemical fastener.

In various embodiments and with reference to <FIG>, coupling <NUM> may be configured as a conduit configured to connect a first double wall pipe <NUM>-<NUM> to a second double wall pipe <NUM>-<NUM>. In this regard coupling <NUM> may be configured to define a first fluid channel that is capable of providing fluid communication between first pipe <NUM>-<NUM> and first pipe <NUM>-<NUM>. Coupling <NUM> may further define a second fluid communication channel configured to provide fluid communication between second pipe <NUM>-<NUM> and second pipe <NUM>-<NUM>. This fluid communication is further facilitated by passage <NUM>-<NUM> and passage <NUM>-<NUM>. In this regard, passages <NUM> are configured to conduct fluids leaked from first pipe <NUM> into the volume defined between first pipe <NUM> and second pipe <NUM>. These passages <NUM> may be configured to conduct the leaked fluid to any suitable drain point.

First piloted flange <NUM> comprises a stop <NUM>. Stop <NUM> is configured to ensure proper installation depth and alignment of first piloted flange <NUM>. Stop <NUM> may be defined as a radial stop that is configured to abut a first abutment structure <NUM>. First abutment structure <NUM> is defined along or on a structure that defines minor diameter receivable slot <NUM>. Similarly, second piloted flange <NUM> comprises and/or include a stop <NUM>. Stop <NUM> is configured to ensure proper installation depth and alignment of second piloted flange <NUM>. Stop <NUM> is installable against or may be configured to abut a second abutment structure <NUM>. Second abutment structure <NUM> is defined on a structure that defines major diameter receivable slot <NUM>.

In various embodiments, the double wall pipe structures, couplings, fittings, and support structures reduce the complexity of manufacturing, the cost of manufacturing, and the overall weight of the assembly. By employing the various structures discussed herein, the manufacturer ability and the cost of manufacture of double wall pipes is improved.

Benefits and advantages have been described herein with regard to specific embodiments. However, such benefits, advantages, and any elements that may cause any benefit or advantage to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. Reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more.

Claim 1:
A double wall pipe assembly, comprising:
a coupling (<NUM>; <NUM>; <NUM>; <NUM>) defining a minor diameter receivable slot (<NUM>; <NUM>; <NUM>; <NUM>) and a major diameter receivable slot (<NUM>; <NUM>; <NUM>; <NUM>); and
a double wall pipe configured to conduct a fluid, the double wall pipe operatively coupled to the coupling (<NUM> ... <NUM>), and comprising:
a first pipe (<NUM>; <NUM>; <NUM>);
a second pipe (<NUM>; <NUM>; <NUM>) sleeved over the first pipe (<NUM>; <NUM>; <NUM>);
a first piloted flange (<NUM>; <NUM>; <NUM>) operatively coupled to the first pipe (<NUM>; <NUM>; <NUM>) and installable in the minor diameter receivable slot (<NUM> ... <NUM>); and
a second piloted flange (<NUM> ... <NUM>) coupled to the second pipe (<NUM>; <NUM>; <NUM>) and installable in the major diameter receivable slot (<NUM> ... <NUM>), wherein:
the coupling (<NUM> ... <NUM>) defines one or more passages (<NUM>; <NUM>; <NUM>) configured to conduct a fluid from a volume defined between the first pipe (<NUM>; <NUM>; <NUM>) and the second pipe (<NUM>; <NUM>; <NUM>) across the coupling (<NUM> ... <NUM>);
the first piloted flange (<NUM>; <NUM>; <NUM>) includes a first seal (<NUM>) and the second piloted flange (<NUM>; <NUM>; <NUM>) includes a second seal (<NUM>);
the first seal (<NUM>) is compressible against a first wall portion of the coupling (<NUM> ... <NUM>) defining the minor diameter receivable slot (<NUM> ... <NUM>);
the second seal (<NUM>) is compressible against a second wall portion of the coupling defining the major diameter receivable slot (<NUM> ... <NUM>); and
compression of the first seal (<NUM>) and the second seal (<NUM>) retains the first pipe (<NUM>; <NUM>; <NUM>) and the second pipe (<NUM>; <NUM>; <NUM>) to the coupling (<NUM> ... <NUM>), characterised in that:
the first piloted flange (<NUM>; <NUM>; <NUM>) further comprises a first stop (<NUM>) that is configured to abut the first wall portion defining the minor diameter receivable slot (<NUM> ... <NUM>);
the second piloted flange (<NUM>; <NUM>; <NUM>) comprises a second stop (<NUM>) that is configured to abut the second wall portion defining the major diameter receivable slot (<NUM> ... <NUM>); and
the first stop (<NUM>) is positioned on the first piloted flange (<NUM>; <NUM>; <NUM>) to facilitate a proper installation depth and alignment of the first pipe (<NUM>; <NUM>; <NUM>) and the second pipe (<NUM>; <NUM>; <NUM>) in the coupling (<NUM> ... <NUM>).