Patent Description:
Vessels are used to contain fluids for a variety of applications. For example, some common uses for vessels include holding of hydraulic fluid for fluid-operated consumers, or holding of lubricant for lubricating moving parts of a machine. To provide access to the fluid in the vessel, the vessel will often contain one or more through-wall penetrations. For example, an oil tank for lubricating parts of an aircraft engine may include a separate penetration for each interfacing component of the vessel, including an oil fill port, air/oil separator, oil quality monitor, sight glass, or the like.

The following documents may provide technical background to the present disclosure: <CIT> according to the preamble of claim <NUM>; <CIT>; <CIT>; and <CIT>.

Some vessels of the type described above use a container wall made of metal because it is durable enough to withstand more severe environmental conditions, and is typically easy to fabricate using conventional manufacturing processes. However, in the aerospace industry, for example, weight savings of such vessels is often desirable.

Accordingly, one aspect of the present disclosure provides a light-weight composite vessel for containing operating fluid of an aircraft device, such as hydraulic or lubricating oil. The composite vessel may be fabricated from a fiber-reinforced polymer-matrix composite, which has a specific strength comparable to or greater than that of metal, but which can be provided at a much lighter weight than its metal counterpart.

One problem with composite vessels, however, is that through-wall penetrations in the vessel can subject the end grain of the composite to the fluid contained in the vessel and/or to external environment conditions. This can enable the internal fluid and/or external contaminants to wick into the exposed end grain, thereby resulting in a reduction in composite strength. This problem of end grain exposure can be addressed by molding in the penetration opening, leaving the end grain covered by a resin rich layer. However, the positional accuracy that is achievable with a molding process frequently will not meet the requirements of the application.

As defined in appended claim <NUM>, a composite vessel fitting for a through-wall penetration with an exposed end grain of the composite vessel is provided, the fitting including a sealing surface arrangement configured to seal against the composite vessel and protect the end grain from exposure to internal fluid and/or external environment while preventing leakage of the vessel contents.

According to another aspect, a composite vessel includes: a composite wall forming an internal chamber for containing a fluid, the composite wall having at least one through-wall penetration and an exposed end grain at the through-wall penetration; and the composite vessel fitting according to any of the foregoing secured to the composite wall at the through-wall penetration, in which the sealing surface arrangement of the fitting sealingly engages the composite wall and protects the end grain from exposure to fluid inside of the internal chamber and/or external environment outside of the vessel.

According to another aspect, a composite vessel fitting for a through-wall penetration with an exposed end grain of the composite vessel is provided, the fitting including: an outer part configured to overlie at least a portion of an outer surface of the composite vessel; an inner part configured to overlie at least a portion of an inner surface of the composite vessel; a through-wall part configured to extend between the inner and outer parts across the penetration having the exposed end grain; an outer seal arrangement including at least one outer seal having a first sealing surface, in which the outer seal arrangement is configured to cooperate with the outer part such that the first sealing surface sealingly engages the outer surface of the composite vessel to restrict migration of environmental contaminants to the end grain of the composite vessel; and an inner seal arrangement including at least one inner seal having second and third sealing surfaces, in which the inner seal arrangement is configured to cooperate with the inner part and the through-wall part such that the second sealing surface sealingly engages the inner surface of the composite vessel and the third sealing surface seals a leak path or interface between the inner part and through-wall part, thereby restricting fluid from the vessel migrating to the end grain of the composite vessel.

According to another aspect, a fitting for a composite vessel includes: an inner portion having a central bore defined by a flanged portion and an inner face for abutting an inner surface of the vessel, the inner portion having an annular groove that houses an annular face seal that abuts and seals against the inner surface of the vessel and a first set of elongate projections adapted to receive fasteners; an outer portion having a cylindrical surface that is telescopically received by the flanged portion and an inner face for abutting an outer surface of the vessel, a first set of through holes registered with the first set of elongate projections, and a first annular groove that houses an annular face seal that abuts and seals against the outer surface of the vessel; and a seal disposed between the flanged portion and the cylindrical portion.

The following description and the annexed drawings set forth certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features according to aspects of the invention will become apparent from the following detailed description when considered in conjunction with the drawings.

The principles and aspects according to the present disclosure have particular application to composite oil tanks in the aerospace industry, such as an aircraft engine oil tank, and more particularly to composite vessels having through-wall penetrations having an exposed end grain, and thus will be described below chiefly in this context. It is understood, however, that the principles and aspects according to the present disclosure may be applicable to other vessels for containing other types of fluids in other applications, including non-composite vessels or composite vessels without an exposed end grain, in which it may be desirable to seal an edge of the penetration, as would be understood by those having ordinary skill in the art.

Turning initially to <FIG> and <FIG>, shown is an exemplary composite vessel <NUM> including a plurality of exemplary fittings <NUM>, <NUM>, <NUM>, <NUM> in respective through-wall penetrations 14a, 14b, 14c, 14d in a composite wall <NUM> of the vessel <NUM>. In the illustrated embodiment, the composite vessel <NUM> is configured as an oil tank for an aircraft engine (not shown). The composite wall <NUM> forms an internal chamber of the vessel <NUM> for containing the engine oil. The composite wall <NUM> may be made with any suitable composite material, such as a fiber-reinforced polymer-matrix composite. The composite wall <NUM> is configured to be sufficiently strong enough to withstand normal operating conditions, preferably without the use of metal liners. The composite material may be made by any suitable process, such as via pre-pregged sheets of the material that are then stacked and bonded or cured together to provide a composite laminate structure. In the illustrated embodiment, for example, the composite wall <NUM> may be formed by a carbon-fiber reinforced resin-matrix material made with sheets that are conformed to the shape of the vessel and are then laminated together by curing. To facilitate manufacturing and assembly of the composite vessel <NUM>, the composite wall <NUM> of the vessel may be formed in multiple parts, such as two shell halves 18a and 18b that are sealingly coupled together, as shown.

The through-wall penetrations 14a-14d in the composite wall <NUM> form openings in the vessel that enable access to the fluid (e.g., oil) contained therein and/or which may serve as mounting locations for interfacing components. Each penetration (collectively or generally referred to with reference number <NUM>) may be specifically located for interfacing with a different component of the vessel, which these different components (collectively or generally referred to with reference number <NUM>) may then interface with other components in the aircraft system. In the illustrated embodiment, for example, the composite vessel <NUM> includes a separate through-wall penetration 14a, 14b, 14c, 14d for each corresponding component of at least an air/oil separator 20a, a sight gage 20b, an oil outlet 20c (not shown in <FIG>), a mounting clevis 20d, or the like. Each of these through-wall penetrations <NUM> may be adapted to have a different orientation, location or configuration depending on the interfacing component <NUM>.

To provide improved accuracy and alignment of the penetrations <NUM> with the corresponding interfacing components <NUM>, the penetrations <NUM> are machined through the composite wall <NUM> after formation of the vessel structure. Although this post-machining process provides improved accuracy and minimizes cost, the post-machining process also results in an end grain <NUM> of the composite material being exposed at the penetration <NUM> (see e.g., <FIG>, <FIG>, <FIG> and <FIG>). More specifically, at this machined end grain <NUM> of the penetration <NUM>, the fiber ends of the composite material will be exposed, which these fiber ends create pathways for the wicking of fluid or other contaminants into the composite structure. Accordingly, the internal fluid (e.g., engine oil) and/or external environment (e.g., moisture, fuel, water, deicing fluids, , etc.) could migrate to the end grain <NUM> and wick into the composite structure. Such contamination of the composite structure could result in a reduction in composite strength and/or delamination of the composite.

To address at least the foregoing issues, the exemplary fittings <NUM>, <NUM>, <NUM>, <NUM> are configured to seal the respective through-wall penetrations 14a, 14b, 14c, 14d against exposure of the composite end grains <NUM> to fluid in the vessel and/or to the external environment. To provide such sealing and protective functionality, the exemplary fittings <NUM>, <NUM>, <NUM>, <NUM> disclosed herein utilize one or more unique sealing surface arrangements that seal against the composite vessel <NUM> and protect the end grains <NUM> at the respective penetrations <NUM>.

In exemplary embodiments, described in further detail below, the sealing surface arrangement(s) generally include at least a first sealing surface that sealingly engages with an outer surface of the composite vessel, a second sealing surface that sealingly engages with an inner surface of the composite vessel, and a third sealing surface that sealingly engages a through-wall part of the fitting that extends through the penetration. The exemplary sealing surface arrangement may include an outer seal arrangement including at least one outer seal configured to restrict migration of environmental contaminants to the end grain of the composite, and which may also serve as a backup seal to prevent leakage of internal fluid. The exemplary sealing surface arrangement also may include at least one inner seal arrangement including at least one inner seal configured to restrict internal fluid from migrating to the end grain of the composite vessel, and which also may provide a backup seal to external contaminants entering the fluid in the vessel.

As described in the exemplary embodiments below, the fitting also includes structural parts that are configured to cooperate with the fitting sealing surface arrangement to provide a desired load (e.g., preload) that enables the sealing functionality of the fitting. For example, the fitting may generally form a clamp that is configured to exert forces on the opposite inner and outer surfaces of the composite vessel and which fluidly seals the sealing surface arrangement appropriately. In exemplary embodiments, the fitting includes at least an outer part that overlies at least a portion of an outer surface of the composite vessel, an inner part that overlies at least a portion of an inner surface of the composite vessel, and a through-wall part that extends between the inner and outer parts across the penetration having the exposed end grain. Generally, the outer fitting part may be configured to cooperate with the outer seal arrangement to fluidly seal against the outer surface of the vessel to restrict environmental migration to the end grain. The inner fitting part and the through-wall part may be configured to cooperate with the inner seal arrangement to seal against at least the inner surface of the vessel to restrict internal fluid from migrating to the end grain, and by extension, the external environment.

Generally, the respective outer, inner and through-wall parts of the fitting may be made with rigid material(s), such as suitable metal(s) (e.g., aluminum, titanium, steel, composite, molded rigid plastic, or the like), which is/are configured to withstand both the external environmental conditions and exposure to the internal fluid. The respective inner, outer, and/or through-wall parts may be formed in any manner, including machining, <NUM>-D printing, casting, or the like. Depending on the component interface requirements, the outer part may be constructed to have a suitable interface geometry formed (e.g., machined, 3D-printed or blanked) into the part prior to assembly, or may be semi-finished to allow for final machining after assembly to minimize tolerance stack-up. In some embodiments, the fastener-receiver assemblies securing the fitting to the composite through-wall also may be used to secure the interfacing (mating) component to the fitting.

In exemplary embodiments, the outer fitting part may interface directly against the outer surface of the composite vessel, and the inner fitting part may interface directly against the inner surface of the composite vessel. The inner and outer parts may be flat or contoured to the wall profile of the vessel. These respective structural parts interfacing with the vessel wall can distribute load over an area of the composite vessel. Suitable seal housings (e.g., seal grooves or glands) may be formed in or between the inner, outer and/or through-wall parts to hold respective inner seal(s) and outer seal(s) to enable interfacing of the part while providing sealing functionality.

In exemplary embodiments, the major structural components of the fitting may be configured to be non-destructively removable and preferably re-installable on the composite vessel. This enhances the serviceability of the fitting without affecting the overall integrity of the fitting or composite vessel itself. In exemplary embodiments this is achieved using suitable fastener-receiver assemblies that provide suitable securement and loading functionality without the use of adhesives or other attachments that would require destructive removal impacting the integrity of the fitting and/or vessel. It is understood, of course, that certain parts of the fitting, such as the seals and parts of the fastener-receiver assemblies (e.g., nuts and bolts), may be replaced after each use.

Generally, the seal(s) of the sealing surface arrangement are made with suitable resilient material, such as a resilient elastomeric (e.g., nitrile, fluorocarbon, or the like as appropriate for the fluids expected in the application). The respective seal(s) generally may surround each of the respective through-wall penetrations to seal around the entire opening formed by the penetration. In exemplary embodiments, one or more, or preferably all, of the seal(s) provided by the exemplary sealing surface arrangement are standard O-ring seals. The use of standard seal designs enhances the repairability of the fitting and minimizes the overall cost to produce and repair the fitting compared to bespoke gasket designs. It is understood, however, that in some embodiments molded seals (elastomer injected and formed into the grooves in the parts) is another type of seal that could be used instead of standard O-rings.

The following description and annexed drawings set forth certain illustrative embodiments of the exemplary fittings <NUM>, <NUM>, <NUM>, <NUM>, in which similar reference numerals, but in different <NUM>-series intervals, are used to indicate the same or similar parts in the various views. It is understood that the descriptions of each exemplary fitting <NUM>, <NUM>, <NUM>, <NUM> may be applicable to each other, except as noted. It is also understood that aspects of the exemplary fittings <NUM>, <NUM>, <NUM>, <NUM> may be substituted for one another or used in conjunction with one another where applicable.

Turning to <FIG>, <FIG>, a portion of the composite vessel <NUM> having through-wall penetration 14a and fitting <NUM> is shown in further detail. In the illustrated embodiment, the portion of the composite vessel <NUM> including fitting <NUM> is configured to interface with an air/oil separator 20a, also referred to as a deaerator/PRV assembly (also shown in <FIG>). To facilitate alignment and mating of the air/oil separator 20a, the through-wall penetration 14a is a post-machined penetration that forms an opening through the composite wall <NUM>, which exposes an end grain <NUM> of the composite. As such, the exemplary fitting <NUM> includes structural parts and a unique sealing surface arrangement that cooperate with each other to seal the through-wall penetration 14a against exposure of the composite end grain <NUM> to fluid in the vessel and/or contamination from the external environment.

In the illustrated embodiment, the exemplary structural parts of the fitting <NUM> include an outer part <NUM> that overlies at least a portion of an outer surface <NUM> of the composite vessel, an inner part <NUM> that overlies at least a portion of an inner surface <NUM> of the composite vessel, and a through-wall part <NUM> that extends between the inner part <NUM> and outer part <NUM> across the through-wall penetration 14a having the exposed end grain <NUM>. As shown, the exemplary sealing surface arrangement of the fitting <NUM> includes a first sealing surface <NUM> that sealingly engages with the outer surface <NUM> of the composite vessel, a second sealing surface <NUM> that sealingly engages with the inner surface <NUM> of the composite vessel, and a third sealing surface <NUM> that sealingly engages with at least the through-wall part <NUM> of the fitting <NUM> that extends through the penetration 14a. In exemplary embodiments, the structural parts <NUM>, <NUM>, <NUM> of the fitting <NUM> generally form a clamp that exerts forces on the opposite outer and inner surfaces <NUM>, <NUM> of the composite vessel <NUM>, and applies a desired load (e.g., preload) that provides suitable sealing functionality of the sealing surfaces <NUM>, <NUM>, <NUM>. As shown, one or more fastener-receiver assemblies <NUM> of the fitting <NUM> may be provided to apply the desired loads for coupling the fitting <NUM> to the composite wall <NUM> and for loading the sealing surfaces <NUM>, <NUM>, <NUM>.

The exemplary sealing surface arrangement of the fitting <NUM> may include an outer seal arrangement and an inner seal arrangement. In the illustrated embodiment, the outer seal arrangement includes at least one outer seal <NUM> (first seal) having the first sealing surface <NUM>. The outer seal <NUM> is disposed within an annular face seal groove <NUM> (first seal housing) of the outer part <NUM> and fluidly seals against the outer vessel surface <NUM>. The exemplary sealing surface arrangement also includes an inner seal arrangement, which includes two inner seals <NUM>, <NUM> (second and third seals) in the illustrated embodiment, which these two inner seals <NUM>, <NUM> respectively include the second and third sealing surfaces <NUM>, <NUM>. As shown, the inner (second) seal <NUM> is disposed in an annular face seal groove <NUM> (second seal housing) of the inner part <NUM> and fluidly seals against the inner vessel surface <NUM>. The other (third) inner seal <NUM> is disposed in a circumferential groove <NUM> (e.g., standard gland) (third seal housing) of the through-wall part <NUM> of the fitting <NUM> and seals against the through-wall part <NUM> and a portion of the inner part <NUM> to fluidly seal a leak path or interface between the inner part <NUM> and through-wall part <NUM>.

Referring to <FIG>, the exemplary inner part <NUM> of the fitting is shown in further detail. The inner part <NUM> may be formed with a suitable material (e.g., metal, such as titanium or steel; composite; plastic; or the like), which may be made by any suitable process, such as by 3D printing or casting and machining. The inner part <NUM> includes a first face <NUM> that abuts the inner surface <NUM> of the vessel <NUM> and which includes annular groove <NUM> containing seal <NUM>. An inner surface <NUM> forms an opening, such as a central bore <NUM>, through the inner part <NUM>. The inner part <NUM> also includes a second face <NUM> from which elongate projections <NUM> extend to form receivers <NUM> of respective fastener-receiver assemblies <NUM>. In exemplary embodiments, the interior portion of the projections <NUM> may be drilled and tapped to form a threaded receiver <NUM> for receiving fasteners <NUM> (e.g., bolts) of the fastener-receiver assembly <NUM>. As shown, the receivers <NUM> may be tapped for an insert <NUM> (e.g., with a HeliCoil tap) to provide the thread. Alternatively, the fastener-receiver assemblies <NUM> could be formed to accommodate blind rivet nuts or similar attachments. In the illustrated embodiment, the elongate projections <NUM> forming the receivers <NUM> are blind receivers enclosed at their ends to prevent exposure to the internal fluid of the vessel. As shown, the projections forming <NUM> the receivers <NUM> are a first set of receiver projections, and the inner part also may include a second set of receiver projections <NUM> for coupling the mating component 20a (e.g., oil/air separator 20a) to the vessel <NUM> with suitable fasteners <NUM>.

Turning to <FIG>, the exemplary outer part <NUM> and through-wall part <NUM> of the fitting are shown in further detail. As shown, the outer part <NUM> is integral and unitary with the through-wall part <NUM> to form a single piece structure. This one piece structure may be formed with a suitable material (e.g., metal, such as titanium or steel; composite; plastic; or the like), which may be made by any suitable process, such as by 3D printing or casting and machining. In the illustrated embodiment, the outer part <NUM> includes a first face <NUM> that abuts the outer surface <NUM> of the vessel <NUM>. The first face <NUM> of the outer part <NUM> includes annular groove <NUM> that houses seal <NUM> which surrounds the penetration 14a and seals against the outer surface <NUM> of the vessel <NUM>. As shown, the outer part <NUM> includes a plurality of through-holes <NUM> with openings in a second (outer) face <NUM>. The through-holes <NUM> are registered to the elongate projections <NUM> (i.e., receivers <NUM>) of the inner part <NUM> and accommodate the fasteners <NUM> to secure the outer part <NUM> to the inner part <NUM> when the fitting <NUM> is assembled to the vessel <NUM>. The outer part <NUM> also may include a second set of receivers, such as through-holes <NUM>, which are registered to the second set of elongate projections <NUM> to couple the mating component (e.g., air/oil separator 20a) to the vessel <NUM> with fasteners <NUM>.

As shown, the through-wall part <NUM> is formed as a projection <NUM> that projects from the first face <NUM> of the outer part <NUM> and which can be inserted into the opening (bore <NUM>) of the inner part <NUM> when the fitting <NUM> is assembled to the vessel body. As noted above, the inner (third) seal <NUM> is disposed in circumferential groove <NUM> of the through-wall part <NUM> that axially overlaps with a radially inner surface of the inner part <NUM>, such that the seal <NUM> can fluidly seal a leak path at the interface between the inner part <NUM> and through-wall part <NUM>. To provide fluid communication to the oil/air separator 20a, the through-wall part <NUM> includes an axial through-passage <NUM>.

As is evident in the illustrated embodiment, the outer part <NUM>, through-wall part <NUM> and inner part <NUM> of the fitting <NUM> are configured to be non-destructively removable and re-installable on the composite vessel <NUM>, which enhances the serviceability of the fitting <NUM> without affecting the overall integrity of the fitting <NUM> or composite vessel <NUM> itself. This is achieved using the non-destructively removable fastener-receiver assemblies <NUM> which enable coupling and decoupling the respective parts <NUM>, <NUM>, <NUM> from the composite wall <NUM>. During such servicing, the seal(s) (e.g., <NUM>, <NUM>, <NUM>) may be replaced. In the illustrated embodiment, the respective seals <NUM>, <NUM>, <NUM> are standard O-ring seals (e.g., elastomeric) housed within the respective seal grooves <NUM>, <NUM>, <NUM> to surround and seal the through-wall penetration 14a. The use of such standard O-ring seals enhances the repairability of the fitting <NUM> and minimizes the overall cost to produce and repair the fitting <NUM> compared to a bespoke gasket design.

Although the exemplary fitting <NUM> is shown with the exemplary sealing surface arrangement formed by respective seals <NUM>, <NUM>, and <NUM>, it is understood that greater or fewer number of seals may be provided. For example, referring to <FIG>, another exemplary embodiment of fitting 112a is shown with an additional outer seal 141b on an opposite side of the fastener-receiver assembly <NUM> from seal <NUM>. Alternatively or additionally, additional inner seals (not shown) could be provided on an opposite side of the fastener-receiver assembly <NUM> to seal <NUM>; or additional seals could be provided next to seal <NUM>, for example.

Referring to <FIG>, a portion of the composite vessel <NUM> having through-wall penetration 14b and fitting <NUM> is shown in further detail. In the illustrated embodiment, the portion of the composite vessel <NUM> including fitting <NUM> is configured to interface with sight gage assembly 20b (also shown in <FIG>). To facilitate alignment and mating of the sight gage assembly 20b (also referred to as sight glass assembly), the through-wall penetration 14b is a post-machined penetration that forms an opening through the composite wall <NUM>, which exposes an end grain <NUM> of the composite. As such, the exemplary fitting <NUM> includes structural parts and a unique sealing surface arrangement that cooperate with each other to seal the through-wall penetration 14b against external leakage and exposure of the composite end grain <NUM> to fluid in the vessel and/or contamination from the external environment.

In the illustrated embodiment, the exemplary structural parts of the fitting <NUM> include an outer part <NUM> that overlies at least a portion of an outer surface <NUM> of the composite vessel, an inner part <NUM> that overlies at least a portion of an inner surface <NUM> of the composite vessel, and a through-wall part <NUM> that extends between the inner part <NUM> and outer part <NUM> across the through-wall penetration 14b having the exposed end grain <NUM>. As shown, the exemplary sealing surface arrangement of the fitting <NUM> includes a first sealing surface <NUM> that sealingly engages with the outer surface <NUM> of the composite vessel, a second sealing surface <NUM> that sealingly engages with the inner surface <NUM> of the composite vessel, and a third sealing surface <NUM> that sealingly engages with the through-wall part <NUM> of the fitting <NUM> that extends through the penetration 14b. In exemplary embodiments, the structural parts <NUM>, <NUM>, <NUM> of the fitting <NUM> generally form a clamp that exerts forces on the opposite outer and inner surfaces <NUM>, <NUM> of the composite vessel <NUM>, and applies a desired load (e.g., preload) that provides suitable sealing functionality of the sealing surfaces <NUM>, <NUM>, <NUM>. As shown, one or more fastener-receiver assemblies <NUM> of the fitting <NUM> may be provided to apply the desired loads for coupling the fitting <NUM> to the composite wall <NUM> and for loading the sealing surfaces <NUM>, <NUM>, <NUM>.

The exemplary sealing surface arrangement of the fitting <NUM> may include an outer seal arrangement and an inner seal arrangement. In the illustrated embodiment, the outer seal arrangement includes at least one outer seal <NUM> (first seal) having the first sealing surface <NUM>. The outer seal <NUM> is disposed within an annular face seal groove <NUM> (first seal housing) of the outer part <NUM> and fluidly seals against the outer vessel surface <NUM>. The exemplary sealing surface arrangement also includes an inner seal arrangement, which includes at least one inner seal <NUM> (second seal) in the illustrated embodiment, which this inner seal <NUM> includes both the second and third sealing surfaces <NUM>, <NUM> of the sealing surface arrangement. As shown, the inner (second) seal <NUM> is disposed in a wedge-shaped space <NUM> (second seal housing) that is formed between respective surfaces of the inner part <NUM>, through-part <NUM> and vessel inner surface <NUM>. In the illustrated embodiment, the wedge-shaped space <NUM> (in cross-section) is an annular space that surrounds a radially outer surface of the through-wall part <NUM> and is at least partially formed by a tapered surface <NUM>, or chamfer, of the inner part <NUM>. The tapered surface <NUM> faces radially inwardly toward the through-wall part <NUM>, and faces axially outwardly toward the vessel inner surface <NUM>. In this manner, when the seal <NUM> is loaded via clamping of the fitting <NUM>, the sealing surface <NUM> sealingly engages against the vessel inner surface <NUM> to fluidly seal the interface between the inner part <NUM> and inner surface <NUM>, and the sealing surface <NUM> sealingly engages against the through-wall part <NUM> to fluidly seal a leak path or interface between the inner part <NUM> and through-wall part <NUM>.

The inner part <NUM> may be formed with a suitable material (e.g., metal, such as titanium or steel; composite; plastic; or the like), which may be made by any suitable process, such as by 3D printing or casting and machining. The inner part <NUM> includes a first face <NUM> that abuts the inner surface <NUM> of the vessel <NUM>. The inner part <NUM> also forms the tapered surface <NUM> abutting seal <NUM>. An inner surface <NUM> forms an opening, such as a central bore, through the inner part <NUM>. The inner part <NUM> also includes a second face <NUM> that operatively engages with a part of the fastener-receiver assembly <NUM> to provide clamping load to the composite wall <NUM>. In the illustrated embodiment, a receiver <NUM> in the form of a threaded nut (e.g., locking nut) of the fastener-receiver assembly <NUM> is used to receive a threaded fastener <NUM> which interact to provide at least a portion of the desired load.

In the illustrated embodiment, the outer part <NUM> is integral and unitary with the through-wall part <NUM> to form a single piece structure. This one piece structure may be formed with a suitable metal (e.g., titanium or steel) by any suitable process, such as by 3D printing or casting and machining. In the illustrated embodiment, the outer part <NUM> includes a first face <NUM> that abuts the outer surface <NUM> of the vessel <NUM>. The first face <NUM> of the outer part <NUM> includes annular groove <NUM> that houses seal <NUM> which surrounds the penetration 14b and seals against the outer surface <NUM> of the vessel <NUM>. As shown, the outer part <NUM> includes a plurality of receivers <NUM> with openings in a second (outer) face <NUM> that are adapted to receive corresponding fasteners <NUM> to couple the mating component (e.g., housing 21a of sight glass assembly 20b) to the vessel <NUM>.

The through-wall part <NUM> is formed as a projection <NUM> that axially projects from the first face <NUM> of the outer part <NUM> and which can be inserted into the opening (bore) of the inner part <NUM> when the fitting <NUM> is assembled to the vessel body. As shown in the illustrated embodiment, an end portion of the through-wall part <NUM> is threaded with radially outward threads to form the fastener <NUM> of the fastener-receiver assembly <NUM>, which interacts with threads of the receiver <NUM> to provide and maintain the clamping load. To provide fluid communication to or visualization through a sight glass 21b of the sight-glass assembly 20b, the through-wall part <NUM> includes an axial through-passage <NUM>.

As is evident in the illustrated embodiment, the outer part <NUM>, through-wall part <NUM> and inner part <NUM> of the fitting <NUM> are configured to be non-destructively removable and re-installable on the composite vessel <NUM>, which enhances the serviceability of the fitting <NUM> without affecting the overall integrity of the fitting <NUM> or composite vessel <NUM> itself. This is achieved using the non-destructively removable fastener-receiver assemblies <NUM> which enable coupling and decoupling the respective parts <NUM>, <NUM>, <NUM> from the composite wall <NUM>. During such servicing, the seal(s) (e.g., <NUM>, <NUM>) may be replaced. In the illustrated embodiment, the respective seals <NUM>, <NUM>, are standard O-ring seals (e.g., elastomeric) housed within the respective seal housings <NUM>, <NUM> to surround and seal the through-wall penetration 14b. The use of such standard O-ring seals enhances the repairability of the fitting <NUM> and minimizes the overall cost to produce and repair the fitting <NUM> compared to a bespoke gasket design.

Referring to <FIG> and <FIG>, a portion of the composite vessel <NUM> having through-wall penetration 14c and fitting <NUM> is shown in further detail. In the illustrated embodiment, the portion of the composite vessel <NUM> including fitting <NUM> is configured to interface with one of the oil outlets on the bottom of the tank (not shown in <FIG>). To facilitate alignment and mating of oil strainer with oil outlet port 20c, the through-wall penetration 14c is a post-machined penetration that forms an opening through the composite wall <NUM>, which exposes an end grain <NUM> of the composite. As such, the exemplary fitting <NUM> includes structural parts and a unique sealing surface arrangement that cooperate with each other to seal the through-wall penetration 14c against exposure of the composite end grain <NUM> to fluid in the vessel and/or contamination from the external environment.

In the illustrated embodiment, the exemplary structural parts of the fitting <NUM> include an outer part <NUM> that overlies at least a portion of an outer surface <NUM> of the composite vessel, an inner part <NUM> that overlies at least a portion of an inner surface <NUM> of the composite vessel, and a through-wall part <NUM> that extends between the inner part <NUM> and outer part <NUM> across the through-wall penetration 14c having the exposed end grain <NUM>. As shown, the exemplary sealing surface arrangement of the fitting <NUM> includes a first sealing surface <NUM> that sealingly engages with the outer surface <NUM> of the composite vessel, a second sealing surface <NUM> that sealingly engages with the inner surface <NUM> of the composite vessel, and a third sealing surface <NUM> that sealingly engages with the through-wall part <NUM> of the fitting <NUM> that extends through the penetration 14c. In exemplary embodiments, the structural parts <NUM>, <NUM>, <NUM> of the fitting <NUM> generally form a clamp that exerts forces on the opposite outer and inner surfaces <NUM>, <NUM> of the composite vessel <NUM>, and applies a desired load (e.g., preload) that provides suitable sealing functionality of the sealing surfaces <NUM>, <NUM>, <NUM>. As shown, one or more fastener-receiver assemblies <NUM> of the fitting <NUM> may be provided to apply the desired loads for coupling the fitting <NUM> to the composite wall <NUM> and for loading the sealing surfaces <NUM>, <NUM>, <NUM>.

The exemplary sealing surface arrangement of the fitting <NUM> may include an outer seal arrangement and an inner seal arrangement. In the illustrated embodiment, outer seal arrangement includes at least one outer seal <NUM> (first seal) having the first sealing surface <NUM>. The outer seal <NUM> is disposed within an annular face seal groove <NUM> (first seal housing) of the outer part <NUM> and fluidly seals against the outer vessel surface <NUM>. The exemplary sealing surface arrangement also includes an inner seal arrangement, which includes at least one inner seal <NUM> (second seal) in the illustrated embodiment, which this inner seal <NUM> includes both the second and third sealing surfaces <NUM>, <NUM> of the sealing surface arrangement. As shown, the inner (second) seal <NUM> is disposed in a wedge-shaped space <NUM> (second seal housing) that is formed between respective surfaces of the inner part <NUM>, through-part <NUM> and vessel inner surface <NUM>. In the illustrated embodiment, the wedge-shaped space <NUM> (in cross-section) is an annular space that surrounds a radially outer surface of the through-wall part <NUM> and is at least partially formed by a tapered surface <NUM>, or chamfer, of the inner part <NUM>. The tapered surface <NUM> faces radially inwardly toward the through-wall part <NUM>, and faces axially outwardly toward the vessel inner surface <NUM>. In this manner, when the seal <NUM> is loaded via clamping of the fitting <NUM>, or energized (such as via pressurization in the vessel), the sealing surface <NUM> sealingly engages against the vessel inner surface <NUM> to fluidly seal the interface between the inner part <NUM> and inner surface <NUM>, and the sealing surface <NUM> sealingly engages against the through-wall part <NUM> to fluidly seal a leak path or interface between the inner part <NUM> and through-wall part <NUM>.

In the illustrated embodiment, the outer part <NUM> is integral and unitary with the through-wall part <NUM> to form a single piece structure. This one piece structure may be formed with a suitable material (e.g., metal, such as titanium or steel; composite; plastic; or the like), which may be made by any suitable process, such as by 3D printing or casting and machining. In the illustrated embodiment, the outer part <NUM> includes a first face <NUM> that abuts the outer surface <NUM> of the vessel <NUM>. The first face <NUM> of the outer part <NUM> includes annular groove <NUM> that houses seal <NUM> which surrounds the penetration 14c and seals against the outer surface <NUM> of the vessel <NUM>. As shown in <FIG>, the outer part <NUM> may include one or more receivers <NUM> with openings in a second (outer) face <NUM> that are adapted to receive corresponding fasteners (not shown) to couple the mating component (e.g., oil outlet assembly 20c) to the vessel <NUM>. Also as shown, the outer part <NUM> may include other retaining structures, such as a groove <NUM> adapted to receive a retaining ring <NUM> for mounting a screen 21c of the oil outlet assembly 20c.

The through-wall part <NUM> is formed as a projection <NUM> that axially projects from the first face <NUM> of the outer part <NUM> and which can be inserted into the opening (bore) of the inner part <NUM> when the fitting <NUM> is assembled to the vessel body. As shown in the illustrated embodiment, an end portion of the through-wall part <NUM> is threaded with radially inward threads to form the fastener <NUM> of the fastener-receiver assembly <NUM>, which interacts with threads of the receiver <NUM> to provide and maintain the clamping load. To provide fluid communication with the oil outlet assembly 20c, the through-wall part <NUM> includes an axial through-passage <NUM>.

As is evident in the illustrated embodiment, the outer part <NUM>, through-wall part <NUM> and inner part <NUM> of the fitting <NUM> are configured to be non-destructively removable and re-installable on the composite vessel <NUM>, which enhances the serviceability of the fitting <NUM> without affecting the overall integrity of the fitting <NUM> or composite vessel <NUM> itself. This is achieved using the non-destructively removable fastener-receiver assemblies <NUM> which enable coupling and decoupling the respective parts <NUM>, <NUM>, <NUM> from the composite wall <NUM>. During such servicing, the seal(s) (e.g., <NUM>, <NUM>) may be replaced. In the illustrated embodiment, the respective seals <NUM>, <NUM>, are standard O-ring seals (e.g., elastomeric) housed within the respective seal housings <NUM>, <NUM> to surround and seal the through-wall penetration 14c. The use of such standard O-ring seals enhances the repairability of the fitting <NUM> and minimizes the overall cost to produce and repair the fitting <NUM> compared to a bespoke gasket design.

Referring to <FIG>, a portion of the composite vessel <NUM> having through-wall penetration 14d and fitting <NUM> is shown in further detail. In the illustrated embodiment, the portion of the composite vessel <NUM> including fitting <NUM> is configured to interface with mounting clevis assembly 20d (also shown in <FIG>). To facilitate alignment and mating of mounting clevis assembly 20d, the through-wall penetration 14d is a post-machined penetration that forms an opening through the composite wall <NUM>, which exposes an end grain <NUM> of the composite. As such, the exemplary fitting <NUM> includes structural parts and a unique sealing surface arrangement that cooperate with each other to seal the through-wall penetration 14d against leakage and exposure of the composite end grain <NUM> to fluid in the vessel and/or contamination from the external environment.

In the illustrated embodiment, the exemplary structural parts of the fitting <NUM> include an outer part <NUM> that overlies at least a portion of an outer surface <NUM> of the composite vessel, an inner part <NUM> that overlies at least a portion of an inner surface <NUM> of the composite vessel, and a through-wall part that extends between the inner part <NUM> and outer part <NUM> across the through-wall penetration 14d having the exposed end grain <NUM>.

In the illustrated embodiment, the through-wall part is the fastener-receiver assembly <NUM>, which is separate and discrete from both the outer part <NUM> and the inner part <NUM>. As shown, the fastener-receiver assembly <NUM> includes at least one fastener <NUM>, such as a bolt, that serves as a projection which axially extends through the penetration 14d from outside to inside the vessel <NUM>. The fastener <NUM> is received by the receiver <NUM>, such a nut (e.g., locking nut), in which interaction via the respective threads provides and maintains the clamping load. As shown in the illustrated embodiment, the receiver <NUM> is formed as an acorn nut in which the interior portion forms a blind hole that receives the fastener <NUM> and encloses the end of the receiver <NUM> from fluid exposure. The fitting <NUM> primarily is used as a mount for the mounting clevis 20d, and therefore no axial through-passage for communicating fluid is provided in the through-wall part (fastener-receiver assembly <NUM>).

As shown, the exemplary sealing surface arrangement of the fitting <NUM> includes a first sealing surface <NUM> that sealingly engages with the outer surface <NUM> of the composite vessel, a second sealing surface <NUM> that sealingly engages with the inner surface <NUM> of the composite vessel, and a third sealing surface <NUM> that sealingly engages with the through-wall part (fastener-receiver assembly <NUM>) of the fitting <NUM> that extends through the penetration 14d. In exemplary embodiments, the structural parts <NUM>, <NUM>, <NUM> of the fitting <NUM> generally form a clamp that exerts forces on the opposite outer and inner surfaces <NUM>, <NUM> of the composite vessel <NUM>, and applies a desired load (e.g., preload) that provides suitable sealing functionality of the sealing surfaces <NUM>, <NUM>, <NUM>. As shown, one or more fastener-receiver assemblies <NUM> of the fitting <NUM> may be provided to apply the desired loads for coupling the fitting <NUM> to the composite wall <NUM> and for loading the sealing surfaces <NUM>, <NUM>, <NUM>.

The exemplary sealing surface arrangement of the fitting <NUM> may include an outer seal arrangement and an inner seal arrangement. In the illustrated embodiment, the outer seal arrangement includes at least one outer seal <NUM> (first seal) having the first sealing surface <NUM>. The outer seal <NUM> is disposed within an annular face seal groove <NUM> (first seal housing) of the outer part <NUM> and fluidly seals against the outer vessel surface <NUM>. The exemplary sealing surface arrangement also includes an inner seal arrangement, which includes at least one inner seal <NUM> (second seal) in the illustrated embodiment, which this inner seal <NUM> includes both the second and third sealing surfaces <NUM>, <NUM> of the sealing surface arrangement. As shown, the inner (second) seal <NUM> is disposed in a wedge-shaped space <NUM> (second seal housing) that is formed between respective surfaces of the inner part <NUM>, through-part (fastener-receiver assembly <NUM>) and vessel inner surface <NUM>.

The inner part <NUM> may be formed with a suitable material (e.g., metal, such as titanium or steel; composite; plastic; or the like), which may be made by any suitable process, such as by 3D printing or casting and machining. The inner part <NUM> includes a first face <NUM> that abuts the inner surface <NUM> of the vessel <NUM>. An inner surface <NUM> forms an opening, such as a central bore, through the inner part <NUM>. The inner part <NUM> also includes a second face <NUM> that operatively engages with a part of the fastener-receiver assembly <NUM> to provide clamping load to the composite wall <NUM>. In the illustrated embodiment, a receiver <NUM> in the form of a threaded nut (e.g., locking nut) of the fastener-receiver assembly <NUM> is used to receive a threaded fastener <NUM> which interact to provide at least a portion of the desired load.

The outer part <NUM> may be formed with a suitable material (e.g., metal, such as titanium or steel; composite; plastic; or the like), which may be made by any suitable process, such as by 3D printing or casting and machining. In the illustrated embodiment, the outer part <NUM> includes a first face <NUM> that abuts the outer surface <NUM> of the vessel <NUM>. The first face <NUM> of the outer part <NUM> includes annular groove <NUM> that houses seal <NUM> which surrounds the penetration 14d and seals against the outer surface <NUM> of the vessel <NUM>. As best shown in <FIG>, the outer part <NUM> includes through-holes <NUM> with openings in a second (outer) face <NUM>. The through-holes <NUM> are registered to correspond with the receivers <NUM> such that the outer part <NUM> and inner part <NUM> can assembled to the vessel <NUM>.

The receiver <NUM> (e.g., nut) forming part of the through-wall part (fastener-receiver assembly <NUM>) also includes a projection <NUM> at its upper (outward) end which is received into the opening (bore) of the inner part <NUM> when the fitting <NUM> is assembled to the vessel body. The projection <NUM> includes a tapered surface <NUM>, which cooperates with the inner part <NUM> and vessel inner surface <NUM> to form the annular wedge-shaped space <NUM> that houses the inner seal <NUM>. The tapered surface <NUM> faces radially outwardly toward the inner part <NUM>, and faces axially outwardly toward the vessel inner surface <NUM>. In this manner, when the seal <NUM> is loaded via clamping of the fitting <NUM>, the sealing surface <NUM> sealingly engages against the vessel inner surface <NUM> to fluidly seal the interface between the inner part <NUM> and inner surface <NUM>, and the sealing surface <NUM> sealingly engages against the through-wall part (fastener-receiver assembly <NUM> in the illustrated embodiment) to fluidly seal a leak path or interface between the inner part <NUM> and through-wall part (fastener-receiver assembly <NUM>). In this manner, the seal is formed between surfaces <NUM>, <NUM> and <NUM>.

As is evident in the illustrated embodiment, the outer part <NUM>, through-wall part (fastener-receiver assembly <NUM>) and inner part <NUM> of the fitting <NUM> are configured to be non-destructively removable and re-installable on the composite vessel <NUM>, which enhances the serviceability of the fitting <NUM> without affecting the overall integrity of the fitting <NUM> or composite vessel <NUM> itself. This is achieved using the non-destructively removable fastener-receiver assemblies <NUM> which enable coupling and decoupling the respective parts <NUM>, <NUM>, <NUM> from the composite wall <NUM>. During such servicing, the seal(s) (e.g., <NUM>, <NUM>) may be replaced. In the illustrated embodiment, the respective seals <NUM>, <NUM>, are standard O-ring seals (e.g., elastomeric) housed within the respective seal housings <NUM>, <NUM> to surround and seal the through-wall penetration 14d. The use of such standard O-ring seals enhances the repairability of the fitting <NUM> and minimizes the overall cost to produce and repair the fitting <NUM> compared to a bespoke gasket design.

An exemplary composite vessel and exemplary fittings have been described herein. In the exemplary embodiment(s), the fitting includes a sealing surface arrangement that seals against the composite vessel, protects against leakage of the vessel contents, and protects the end grain from exposure to internal fluid and/or external environment. The fitting includes an outer part, an inner part, and a through-wall part extending between the inner and outer parts across the penetration. An outer seal arrangement includes an outer seal having a first sealing surface that seals against the outer surface of the composite vessel to restrict environmental contaminants migrating to the end grain. An inner seal arrangement includes at least one inner seal having second and third sealing surfaces. The second sealing surface seals against the inner surface of the composite vessel and the third sealing surface seals a leak path or interface between the inner part and through-wall part to restrict internal fluid migrating to the end grain.

At least one advantage of the exemplary fitting(s) includes a fully-sealed adapter for a composite vessel offering protection of the end grain of the laminate at penetrations through the wall of such composite vessel from both environmental and/or fluid contents using conventional O-ring type seals and glands to reduce cost and improve repairability.

At least one other advantage includes a fully-sealed adapter for a composite vessel offering flexibility in manufacturing to finish the interface prior to installation or post-installation to achieve the desired positional tolerance of the finished interface to reduce cost and processing complexity of the composite component.

The concepts provided here are proven capable of withstanding pressure cycling while retaining the ability to easily fabricate and assemble.

Claim 1:
A composite vessel (<NUM>) comprising:
a composite wall (<NUM>) forming an internal chamber for containing a fluid, the composite wall (<NUM>) having at least one through-wall penetration (14a-14d) and an exposed end grain (<NUM>) at the through-wall penetration (14a-14d); and
a composite vessel fitting (<NUM>, <NUM>, <NUM>, <NUM>) secured to the composite wall (<NUM>) at the through-wall penetration (14a-14d), the fitting comprising a sealing surface arrangement that seals against opposite inner (<NUM>) and outer surfaces (<NUM>) of the composite vessel (<NUM>) and protects the end grain (<NUM>) from exposure to internal fluid and external environment by preventing migration of environment materials from the outer surface (<NUM>) to the inner surface (<NUM>) while preventing leakage of the vessel contents;
wherein the fitting (<NUM>, <NUM>, <NUM>, <NUM>) is non-destructively removable from the composite vessel (<NUM>); and
characterised in that
the sealing surface arrangement includes:
a first sealing surface (<NUM>; <NUM>; <NUM>; <NUM>) that interfaces with the outer surface (<NUM>) of the composite vessel and fluidly seals against the outer surface (<NUM>);
a second sealing surface (<NUM>; <NUM>; <NUM>; <NUM>) that interfaces with the inner surface (<NUM>) of the composite vessel and fluidly seals against the inner surface (<NUM>); and
a third sealing surface (<NUM>; <NUM>; <NUM>; <NUM>) that interfaces and seals against a through-wall part (<NUM>) of the fitting, wherein the through-wall part (<NUM>) extends through the penetration (14a-14d) of the composite vessel.