Patent Description:
Accordingly, those skilled in the art continue with research and development efforts in the field of fire seals.

<CIT>, in accordance with its Abstract, states compositions of injection molded articles, multilayer extruded articles, and 3D printed articles with improved flame properties and with improved melt dripping properties are disclosed. Improved flame resistant articles may be beneficial for a large number of injection molded parts, 3D printed parts, and extruded parts. Reduced melt dripping also may be beneficial for such applications. Methods for using compositions, printed parts, molded parts, and extruded parts are disclosed.

<CIT>, in accordance with its Abstract, states a rigid electrical panel and a method of manufacturing a rigid electrical panel is provided with a fire protection layer on at least one side. The fire protection layer comprises fibres and an intumescent material. The rigid electrical panel comprises electrical conductors embedded in a rigid organic matrix composite. In the event of a fire, the fire protection layer protects the embedded electrical conductors, and any other features or components carried by the electrical panel.

<CIT>, in accordance with its Abstract, states fire-retardant composites, methods of making fire-retardant composites, and use thereof are described. A fire-retardant composite can include at least two fire-retardant laminates, and a porous thermoplastic core material disposed between the at least two fire-retardant laminates. Each laminate can have one or more ply, each of the plies can include a plurality of fibers in a thermoplastic polymer matrix that includes a fire-retardant composition. The fire-retardant composite meets European fire-retardant standards for rail transportation.

Disclosed are fire seals comprising: a bulk material that decomposes at a decomposition temperature (TD); and a phase-changing material (<NUM>) having a phase transition temperature (TT) and that is supported by the bulk material (<NUM>), and wherein: the bulk material (<NUM>) is fire resistant; and the phase-changing material (<NUM>) comprises particles having an average particle size of less than <NUM>.

In other examples, the disclosed fire seal includes a bulk material having a decomposition temperature. The bulk material is fire resistant. The fire seal further includes a phase-changing material supported by the bulk material, the phase-changing material having a phase transition temperature. The fire seal further includes a second phase-changing material supported by the bulk material, the second phase-changing material having a second phase transition temperature. A difference between the phase transition temperature and the second phase transition temperature is at least <NUM>. A difference between the decomposition temperature and the phase transition temperature is at least <NUM>. Further, a difference between the decomposition temperature and the second phase transition temperature is at least <NUM>.

Also disclosed are multi-member assemblies.

In some examples, the disclosed multi-member assembly includes a first structural member, a second structural member opposed from the first structural member, and a fire seal positioned between the first structural member and the second structural member, the fire seal includes a bulk material and a phase-changing material supported by the bulk material. The bulk material is fire resistant.

Also disclosed are fire-sealing methods.

In some examples, the disclosed fire-sealing method includes positioning a fire seal between a first structural member and a second structural member. The fire seal includes a bulk material and a phase-changing material supported by the bulk material. The bulk material is fire resistant.

Other examples of the disclosed fire seals and associated multi-member assemblies and fire-sealing methods will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

The following detailed description refers to the accompanying drawings, which illustrate specific examples described by the present disclosure. Other examples having different structures and operations do not depart from the scope of the present disclosure. Like reference numerals may refer to the same feature, element, or component in the different drawings.

Illustrative, non-exhaustive examples, which may be, but are not necessarily, claimed, of the subject matter according to the present disclosure are provided below. Reference herein to "example" means that one or more feature, structure, element, component, characteristic, and/or operational step described in connection with the example is included in at least one aspect, embodiment, and/or implementation of the subject matter according to the present disclosure. Thus, the phrases "an example," "another example," "one or more examples," and similar language throughout the present disclosure may, but do not necessarily, refer to the same example. Further, the subject matter characterizing any one example may, but does not necessarily, include the subject matter characterizing any other example. Moreover, the subject matter characterizing any one example may be, but is not necessarily, combined with the subject matter characterizing any other example.

For the purpose of this disclosure, the terms "coupled," "coupling," and similar terms refer to two or more elements that are joined, linked, fastened, attached, connected, put in communication, or otherwise associated (e.g., mechanically, electrically, fluidly, optically, electromagnetically) with one another. In various examples, the elements may be associated directly or indirectly. As an example, element A may be directly associated with element B. As another example, element A may be indirectly associated with element B, for example, via another element C. It will be understood that not all associations among the various disclosed elements are necessarily represented. Accordingly, couplings other than those depicted in the figures may also exist.

References throughout the present specification to features, advantages, or similar language used herein do not imply that all of the features and advantages that may be realized with the examples disclosed herein should be, or are in, any single example. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an example is included in at least one example. Thus, discussion of features, advantages, and similar language used throughout the present disclosure may, but do not necessarily, refer to the same example.

Referring to <FIG>, disclosed is a fire seal <NUM>. The fire seal <NUM> may be used in a vehicle, such as an aerospace component. The fire seal <NUM> assists in absorbing and dispersing heat within a multi-member assembly <NUM>. The material properties of the fire seal <NUM> are selectively controlled by the chemistry of the fire seal <NUM>. Factors include size, distribution, and fraction of inclusions and additives in the fire seal <NUM> as shown and described herein. The materials of the fire seal <NUM> are selected for high temperature and harsh environments, ignition, burn-through, hold-pressure, stability against variety of typical fluids, tolerance to thermal experience, and other requirements.

Referring to <FIG>, the fire seal <NUM> includes a bulk material <NUM>. The bulk material <NUM> is fire resistant. The bulk material <NUM> decomposes at a decomposition temperature TD. In some examples, the decomposition temperature TD is at least <NUM>. In other examples, the decomposition temperature TD is at least <NUM>. In yet other examples, the decomposition temperature TD is at least <NUM>.

The bulk material <NUM> may include any material having requisite material properties for the fire seal <NUM>. The bulk material <NUM> may include a seal matrix-material. In some examples, the bulk material <NUM> comprises a ceramic material. In other examples, the bulk material <NUM> comprises a polymeric material. For example, the bulk material <NUM> may include aramid fibers, such as, for example, para-aramid material (e.g., KEVLAR brand fibers commercially available from DuPont) and/or a meta-aramid material (e.g., NOMEX brand fibers/sheets commercially available from DuPont). In other examples, the bulk material <NUM> may include ceramic oxide fibers.

Further, the bulk material <NUM> may include one or more of an amorphous material, a fabric material, a foam material, and a felt material. Examples of a fabric material include Nextel™ (AF-<NUM>, AF-<NUM>-<NUM>) (trademarks of <NUM>™), Nomex® (HT-<NUM>, HT001) (trademarks of Dupont™), Dacron™ (trademark of Dupont™), S2, and E-glass.

Referring to <FIG>, the fire seal <NUM> further includes a phase-changing material <NUM> supported by the bulk material <NUM>. The phase-changing material <NUM> includes particles having various sizes and distribution within the fire seal <NUM>. The phase-changing material <NUM> includes particles having an average particle size of less than <NUM>, such as particles having an average particle size within the range of <NUM> to <NUM>, or particles having an average particle size within the range of <NUM> to <NUM>, or particles having an average particle size within the range of <NUM> to <NUM>. In other examples, the phase-changing material <NUM> includes an inorganic material (e.g., magnesium chloride hexahydrate (MgCl<NUM>. <NUM><NUM>O)). In yet other examples, the phase-changing material <NUM> comprises a metallic material, such as a binary alloy (e.g., Al-Si, which phase changes at <NUM> (or about <NUM>), or Al-Sn, which phase changes at <NUM> (or about <NUM>)) or a ternary alloy (e.g., Cu-Al-Si, which phase changes at <NUM> (or about <NUM>)). Further, in one or more examples, the phase-changing material <NUM> may include a paraffin material.

The phase-changing material <NUM> absorbs heat within the fire seal <NUM> to reduce and slow material degradation when subjected to high temperatures for long periods of time and at high pressures. Referring to <FIG>, heat input ΔQ into the phase-changing material <NUM> triggers latent-heat conversion, thus absorbing heat as it comes into contact with the fire seal <NUM>. Further, expansion σc of the phase-changing material <NUM> due to phase change of the phase-changing material <NUM> triggers internal compression stress.

The phase-changing material <NUM> has a phase transition temperature TT. In some examples, the phase transition temperature TT is between <NUM> and <NUM> (or approximately <NUM> and approximately <NUM>). In other examples, the phase transition temperature TT is between <NUM> and <NUM> (or approximately <NUM> and approximately <NUM>). In yet other examples, the phase transition temperature TT is between <NUM> and <NUM> (or approximately <NUM> and approximately <NUM>).

In one or more examples, the phase-changing material <NUM> transitions from a solid to a liquid upon reaching the phase transition temperature TT. In other examples, the phase-changing material <NUM> transitions from a first solid to a second solid upon reaching the phase transition temperature TT. In yet other examples, the phase-changing material <NUM> transitions from a solid to a gas upon reaching the phase transition temperature TT.

The phase transition temperature TT and the decomposition temperature TD of the bulk material <NUM> may be different. In some examples, a difference between the phase transition temperature TT and the decomposition temperature TD is at least <NUM>. In other examples, a difference between the phase transition temperature TT and the decomposition temperature TD is at least <NUM>. In yet other examples, a difference between the phase transition temperature TT and the decomposition temperature TD is at least <NUM>.

The fire seal <NUM> may further include a second phase-changing material <NUM> supported by the bulk material <NUM>. In some examples, the second phase-changing material <NUM> has a second phase transition temperature TT2, and a difference between the second phase transition temperature TT2 and the decomposition temperature TD is at least <NUM>. Further, in one or more examples, a difference between a phase transition temperature TT of the phase-changing material <NUM> the second phase transition temperature TT2 is at least <NUM>. The second phase-changing material <NUM> may be compositionally different than the phase-changing material <NUM>. For example, the phase-changing material <NUM> may be magnesium chloride hexahydrate (MgCl<NUM>. <NUM><NUM>O), which phase changes at <NUM> (or about <NUM>), and the second phase-changing material <NUM> may be tin (Sn), which phase changes at <NUM> (or about <NUM>).

Still referring to <FIG>, in one or more examples, the fire seal <NUM> may further comprising a third phase-changing material <NUM> supported by the bulk material <NUM>. The third phase-changing material <NUM> has a third phase transition temperature TT3. In some examples, a difference between the third phase transition temperature TT3 and the decomposition temperature TD is at least <NUM>. In other examples, a difference between the third phase transition temperature TT3 and the decomposition temperature TD is at least <NUM>. For example, the phase-changing material <NUM> may be magnesium chloride hexahydrate (MgCl<NUM>. <NUM><NUM>O), which phase changes at <NUM> (or about <NUM>), the second phase-changing material <NUM> may be tin (Sn), which phase changes at <NUM> (or about <NUM>), and the third phase-changing material <NUM> may be Cu-Al-Si, which phase changes at <NUM> (or about <NUM>).

The fire seal <NUM> may further include a nano-clay material <NUM> supported by the bulk material <NUM>. The nano-clay material <NUM> may be incorporated as a single layer or multiple layers to increase the diffusion barrier. For example, a high tortuosity diffusion path in the fire seal <NUM> material due to the addition of nano-clay material <NUM> may reduce the oxygen diffusion rate. A multi-layer assembly including nano-clay material <NUM> may help achieve ultra-low diffusion coefficients in the fire seal <NUM>.

In addition to nano-clay material <NUM>, in one or more examples, the fire seal <NUM> may include one or more additives to promote, among other things, CO<NUM> evolution beyond specific temperature thresholds. Specific examples of such additives include, but art not limited to, carbonates (e.g., calcium carbonate and sodium carbonate), bicarbonates (e.g., sodium bicarbonate), glucose, citrates, and the like, and mixtures thereof.

Examples of other additives include one or more of silica, alumina, zirconia, graphene, graphene oxide, and graphite oxide supported by the bulk material <NUM>. Referring to <FIG>, in one or more examples, the fire seal <NUM> may include an infrared-reflective coating <NUM> on an outside surface <NUM> of the fire seal <NUM>. The infrared-reflective coating <NUM> may include inclusions that limit heat absorption in the material. The infrared-reflective coating <NUM> may include, for example, infrared-reflective pigments (e.g., leafing aluminum flakes) in a binder (e.g., thermoset resin).

In some examples, a fire seal <NUM> includes a bulk material <NUM> having a decomposition temperature TD. The bulk material <NUM> is fire resistant. The fire seal <NUM> further includes a phase-changing material <NUM> supported by the bulk material <NUM>. The phase-changing material <NUM> has a phase transition temperature TT.

Referring to <FIG>, the fire seal <NUM> further includes a second phase-changing material <NUM> supported by the bulk material <NUM>, the second phase-changing material <NUM> having a second phase transition temperature TT2. In one or more examples, a difference between the phase transition temperature TT and the second phase transition temperature TT2 is at least <NUM>. In other examples, a difference between the decomposition temperature TD and the phase transition temperature TT is at least <NUM> and a difference between the decomposition temperature TD and the second phase transition temperature TT2 is at least <NUM>.

In one or more examples, see <FIG>, the fire seal <NUM> includes a third phase-changing material <NUM> supported by the bulk material <NUM>. The third phase-changing material <NUM> has a third phase transition temperature TT3. In some examples, a difference between the third phase transition temperature TT3 and the phase transition temperature TT is at least <NUM> and a difference between the third phase transition temperature TT3 and the second phase transition temperature TT2 is at least <NUM>.

Referring to <FIG>, disclosed is a multi-member assembly <NUM>. The multi-member assembly <NUM> includes a first structural member <NUM> and a second structural member <NUM> opposed from the first structural member <NUM>. The multi-member assembly <NUM> further includes a fire seal <NUM> positioned between the first structural member <NUM> and the second structural member <NUM>.

The fire seal <NUM> of the multi-member assembly <NUM> includes a bulk material <NUM>. The bulk material <NUM> is fire resistant. The fire seal <NUM> of the multi-member assembly <NUM> further includes a phase-changing material <NUM> supported by the bulk material <NUM>. In some examples, the first structural member <NUM> of the multi-member assembly <NUM> is an engine and the second structural member <NUM> of the multi-member assembly <NUM> is a pylon.

Also disclosed is a fire-sealing method. The fire-sealing method includes the step of positioning a fire seal <NUM> between a first structural member <NUM> and a second structural member <NUM>. The fire seal <NUM> of the fire-sealing method includes a bulk material <NUM> and a phase-changing material <NUM> supported by the bulk material <NUM>. The bulk material <NUM> is fire resistant. In some examples, the first structural member <NUM> is an engine and wherein the second structural member <NUM> is a pylon.

The phase-changing material <NUM> reversibly triggers latent heat conversion when subjected to specific temperature levels, thereby preventing further increase in temperature. Two or more families of phase-changing material <NUM>, <NUM>, <NUM>, may be incorporated so that successive latent-heat conversion events get triggered at multiple increasingly higher temperature levels. This provides for multiple levels of safety and overall graceful response of seal material in the event of excessive temperature conditions. The fire seal <NUM> bulk material <NUM> incorporates nano-clay material <NUM> inclusions to provide a barrier to oxygen diffusion through the material, thereby restricting self-ignition and burn-through. The fire seal <NUM> and constituent inclusions are coated with IR reflective material, coating <NUM>, to limit the incident temperature rise to an extent, thereby expanding the operation envelope of the current materials. The phase-change of the phase-changing material <NUM> inclusions is accompanied with an associated volume change, creating internal compression stress. This helps in maintaining pressure tightness even when the harsh surrounding conditions tend to create leakage paths. The fire seal <NUM> material may include inclusions that generate CO<NUM> at the highest/extreme expected temperatures so as to extinguish any possible flame propagation through the joint.

The phase-changing material <NUM> and other functional additives supported by the bulk material <NUM> as shown and described herein are selected to enhance performance of seals, such as a fire seal <NUM>. Specifically, phase-changing material <NUM> inclusions in seal matrix-material, or bulk material <NUM>, reversibly absorb incident heat and limit temperature rise due to a latent-heat conversion process. The compressive stress induced due to associated volume change of the phase-changing material <NUM> provides extra benefit by ensuring tight sealing action even when rising temperature externally may lead to leakage through the fire seal <NUM> joint. The phase-changing material <NUM> may be based on solid-liquid or solid-solid phase transitions and is incorporated in sub-micron or plus-micron size along with other functional additives such as nano-clay material <NUM> to address the various functional requirements listed above. The composition and morphology of the phase-changing material <NUM> and bulk material <NUM> may be tailored to achieve desired performance relative to specific applications.

For example, the fire seal <NUM> materials may be selected such that the fire seal <NUM> is fireproof, does not have burn through, does not have backside ignition, is abrasion resistant, promotes self-extinguishing flames, holds pressure up to 30psi (210kPa), includes no hazardous quantity of fluid, vapor or flame can pass from one compartment to another doesn't absorb hazardous quantity of fluids survives in a nacelle/engine environment, is not susceptible to typical fluids (fuels, oils, hydraulic fluid, salt fog, deicing fluid, etc.), can withstand high and low temperatures (such as +500F and -65F (or <NUM> and -<NUM>), is fungus resistant, is sand and dust resistant, can withstand cyclic compression/pressure, is ozone resistant, is tolerant to build tolerances, thermal expansion and contraction, and maneuver deflections, and requires low closing force: ~<NUM>-<NUM> Ib/linear inch (<NUM>-<NUM>/m). Specific polymeric systems that allow repair of damaged bonds through relatively straightforward post-treatment may also be included in the fire seal <NUM>.

Examples of the subject matter disclosed herein may be described in the context of aircraft manufacturing and service method <NUM> as shown in <FIG> and aircraft <NUM> as shown in <FIG>. During pre-production, service method <NUM> may include specification and design (block <NUM>) of aircraft <NUM> and material procurement (block <NUM>). During production, component and subassembly manufacturing (block <NUM>) and system integration (block <NUM>) of aircraft <NUM> may take place. Thereafter, aircraft <NUM> may go through certification and delivery (block <NUM>) to be placed in service (block <NUM>). While in service, aircraft <NUM> may be scheduled for routine maintenance and service (block <NUM>). Routine maintenance and service may include modification, reconfiguration, refurbishment, etc. of one or more systems of aircraft <NUM>.

Each of the processes of service method <NUM> may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include, without limitation, any number of aircraft manufacturers and major-system subcontractors; a third party may include, without limitation, any number of vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.

As shown in <FIG>, aircraft <NUM> produced by service method <NUM> may include airframe <NUM> with a plurality of high-level systems <NUM> and interior <NUM>. Examples of high-level systems <NUM> include one or more of propulsion system <NUM>, electrical system <NUM>, hydraulic system <NUM>, and environmental system <NUM>. Any number of other systems may be included. Although an aerospace example is shown, the principles disclosed herein may be applied to other industries, such as the automotive industry. Accordingly, in addition to aircraft <NUM>, the principles disclosed herein may apply to other vehicles, e.g., land vehicles, marine vehicles, space vehicles, etc..

The disclosed fire seals and fire-sealing methods shown or described herein may be employed during any one or more of the stages of the manufacturing and service method <NUM>. For example, components or subassemblies corresponding to component and subassembly manufacturing (block <NUM>) may be fabricated or manufactured in a manner similar to components or subassemblies produced while aircraft <NUM> is in service (block <NUM>). Also, one or more examples of the systems, methods, or combination thereof may be utilized during production stages component and subassembly manufacturing (block <NUM>) and system integration (block <NUM>), for example, by expediting or substantially expediting assembly of or reducing the cost of aircraft <NUM>. Similarly, one or more examples of the systems or method realizations, or a combination thereof, may be utilized, for example and without limitation, while aircraft <NUM> is in service (block <NUM>) and/or during maintenance and service (block <NUM>).

Claim 1:
A fire seal (<NUM>) comprising:
a bulk material (<NUM>) that decomposes at a decomposition temperature (TD); and
a phase-changing material (<NUM>) having a phase transition temperature (TT) and that is supported by the bulk material (<NUM>), and
wherein:
the bulk material (<NUM>) is fire resistant; and
the phase-changing material (<NUM>) comprises particles having an average particle size of less than <NUM>.