Aircraft internal insulation structure

The invention relates to an insulation structure for the internal insulation of an aircraft in accordance with the preamble of claims 1 and 21st

It is known that the insulation currently used in aircraft of the on Structure located side primary insulation consisting essentially of an insulating base material and a this insulation enveloping foil. The films conventionally used is the Core material of the insulation system being protected against water. In addition, the foil envelope is for attaching the partially bulky insulation. This sheath is usually so dimensioned, after which it has the lowest possible weight. It can be find that because of the relatively thin film when taking place water vapor diffusion through the Film wall of water vapor in the insulation package folienumhüllte occurs. This condenses part of Water vapor from the insulation package. Also go through leaks in the insulation package or in the foil envelope repeatedly diffusing liquid particles such as water, in the Insulation package. The condensation in the insulation package causes an accumulation of liquid Particles (of the water) takes place in insulating material only by additional drying costs persists. This fact therefore is very uncomfortable because the Water accumulation (s) increases the Isolationssytem weight and therefore to an unnecessary Increase in weight (take-off weight) of an airplane performs.

Furthermore, from the document: "DE 198 49 696 A1", a generic insulation structure known is completely enclosed by a film. The film is disposed within an intermediate space, enclose the interior lining and an outer skin of an aircraft. Those film with a penetrating gases and liquids film material realized with the one in Depending on the direction of diffusion of the diffusing through the film wall medium a different diffusion resistance behavior will implement. For details on the extending Diffusion behavior of those film relate, shall not be communicated; but can infer that the film material unspecified considered that films different water characteristics should, so that a return of the accumulated medium (recorded by insulating water) is even conceivable by the foil membrane. That solution adheres far on the downside, that the water (water vapor), which (the) act from outside on the film and by the latter will diffuse, will be initially trapped in the insulation, which may then could escape later through the wrapping films of the insulation package. Without creative additions, on the design of the film (s) make reference that just disclosed information will respect a different diffusion resistance behavior of films difficult to imagine a such specified isolation structure functional rework. It is merely a proposed sheet material which in the direction of diffusion through the film wall diffusing medium (condensed water) of the Folieninnen- to film exterior wall surface a lower diffusion resistance should implement.

This measure would be credibly that a film material that this ability has, on a film surface, the water collected from the foil-wrapped insulation package by the Film can give to the environment without providing a solution. Also mediates Publication: "US 5,565,254 A" proposals for the design of an insulation structure, are integrated to the corresponding insulation packages, and film materials, which mainly to the Product range of GORE are limited. For further improvements, which with the situational transport media correlate with the slides, is silent, the Block letters.

Accordingly, the invention is the object of a generic isolation structure such improve that welded by appropriate measures in a foil envelope Insulation kept dry and also minimizes the transport of water in the insulation package and is supported by the package.

This Auifgabe is solved by the measures indicated in claims 1 and 21st In the further claims are embodiments of such activities.

The invention is more detail in an embodiment shown in the drawings added described. Show it<dl tsize="7" compact="compact"><dt>Fig. 1</dt><dd>an insulation structure with a foil envelope, the asymmetric one Film structure has;</dd><dt>FIG. 2</dt><dd>an insulating structure with a foil envelope, the symmetrical one Film structure has;</dd><dt>Fig. 3</dt><dd>an illustration of water transport through the membrane of a film symmetrical film construction of FIG. 2;</dd><dt>Fig. 4</dt><dd>an insulation structure of FIG 2 with single film coating.</dd><dt>Fig. 5</dt><dd>a representation of mass transfer through membrane pores or pores of a film;</dd><dt>Fig. 6</dt><dd>an illustration of the pore structure at different temperatures;</dd><dt>Fig. 7</dt><dd>the representation of a symmetrical membrane / film;</dd><dt>Fig. 8</dt><dd>the representation of an asymmetric membrane / film;</dd><dt>Fig. 9</dt><dd>the representation of an asymmetric membrane with different layers and different properties;</dd><dt>Fig. 10</dt><dd>the representation of two different films or membranes deviating Porosity with an air gap;</dd><dt>Fig. 11</dt><dd>the presentation of two films or membranes of different chemical Property with an air gap;</dd><dt>Fig. 12</dt><dd>an insulation package respectively insulation structure with a permeable material as Replacement for drainage holes.</dd></dl>

In FIG. 1, an insulation structure is now 10 with a foil envelope 5, the one asymmetrical film structure possesses. This insulation structure 10 considered (the Aircraft outer skin of an airliner insulating) insulation package 1, which completely covered by a Foil envelope 5 is wrapped. This insulation structure 10 is located within a free Interspace 7, for example, by a structural region (an aircraft outer skin) and wall-like lining part is limited, the latter being close to the outer skin of the aircraft is arranged. Compared to that of the initially defined insulation system, which is traditionally in will find a commercial airliner, the insulation structure 10 with two different Wrapping foils 11, 12 realized whose film properties are different. So will a first sheath film 11, which is oriented to the aircraft outer skin, for example as used vapor barrier, on the other hand a second sheath film 12, which is oriented to the aircraft cabin, water vapor-permeable is used. This wrapping foils 11, 12 are by folienendseitig Gluing or welding firmly interconnected. The film material of the first and / or second sheath film 11, 12 is on the film thickness of each wrap sheet 11, 12 different design and / or be of any type. If yet another wrapping foils of the first and / or the second sheath film 11, 12 are stacked or adjacent bayed the Foil envelope 5 are integrated, it is conceivable that also the film material on the Film thickness of the individual wrapping foil is correspondingly different.

Depending on the desired diffusion direction, the diaphragm of the two wrapping foils 11, 12 or Another used wrapping foils on the film thickness (the individual foil) different exhibit porosities. For example, the direction-dependent diffusion behavior of the first Wrapping foil 11 during the flight of an airplane to the outer skin of the area Aircraft structure porous and the cabin area less porous or at a bottom of the stay Aircraft be reversed designed.

Furthermore, the proposed symmetric film structure, a membrane of the individual Wrapping sheet 11, 12 or the other films n ( "n" represents the number of films) into account, each of two or more sheet materials (possibly different type of film) is integrated. The sheet materials for wrapping films, the use of which is proposed with which those different diffusion permeability is to be implemented, are still more detail below considered.

The (figuratively, not shown) of the assembly with a plurality of adjacently stacked Wrapping foils realized foil envelope 5 is modeled after the sandwich construction implemented.

It is further proposed that between the so layered (neighboring) Wrapping films, which are sequentially arranged horizontally, an air gap can be realized, the the transport of the diffusing liquids (water) or the diffusing gaseous Media (water vapor) low (he) can influence.

Returning to the film materials for those wrapping foils, the specified when the asymmetric structure of a membrane can be used are the following versions Measures supplemented, after which the foil envelope 5 to the outer skin portion of the aircraft structure hydrophilic and the cabin area of ​​the aircraft hydrophobic is designed tightly. is After provided that (in a foil envelope 5 with two sheets) the first sheath film 11 having a hydrophilic film material and the second wrapping sheet 12 with a hydrophobic sealing Film material is realized. It is further suggested that the film material of the first and / or second sheath film 11, 12 and / or (if applicable) each further wrapping foils with an n Film material is realized from amorphous, crystalline or semi-crystalline polymers. Regarding the film material, which should be taken into account, is from PTMSP, 6-FDA-Based; PI, PEI, PS, PTFE, Nafion or PET polymer as film material indicated. Also mentions that the hydrophilic first sheath film 11 having a film of silicone material, and the hydrophobic second wrapping film 12 can be realized with a sheet material made of PTFE.

These designs are extended to those which required different Diffusion permeabilities provide hydrophilic or hydrophobic by the advantageous arrangement Construction will be achieved.

An example of this will be those arrangement, according to which a hydrophilic membrane density on the Structure side can absorb and pass well water; the hydrophobic dense membrane on the cabin side will block water passage. The presented transport principle is based here on a solution-diffusion mechanism, the positively at high temperatures, the transport affected. If the membrane is very cold, there will be a very low transport, the addition in Direction of the structure is complicated by the hydrophobic membrane. If the temperature is higher , the water at the structure side easily penetrate into the hydrophobic membrane and because of higher temperature also easily diffuse through the hydrophobic membrane. The selected Therefore example of a combination of materials would PTFE on the cabin side and silicone on the Structure page.

In FIG. 2, a further embodiment of an insulation structure 10 is illustrated, whose Foil envelope 5 is provided with a symmetrical film construction. There is only one (single) third wrapping film 13 into consideration that completely cover the aforementioned insulation package 1 becomes.

It goes without saying that the film ends that third wrapping foil 13 by welding or gluing or otherwise-like additions are firmly attached to seal the insulation package 1 to protect against external influences, respectively.

A version of that wrapping film 13 into account that their symmetric membrane in hydropil high temperatures and is a nature hydrophobic at low temperatures.

Similar to the previously mentioned example of designing a foil envelope 5 with two Wrapping foils 11, 12 is that regarding a symmetrically shaped foil structure Foil envelope 5 suggested that a first film portion 15A of the third sheath film 13, which is oriented to the outer skin portion of the aircraft structure and no temperature dependence subject, is a nature hydrophobic. A second film section 15B of this third sheath film 13, the is oriented to the cabin area of ​​the aircraft and an existing temperature dependence subject, is also a nature hydrophobic, said hydrophobic kind film area capable implement under the influence of low temperatures an increased fluid transport.

Even a further embodiment is conceivable, according to which the first and second film section 15A of third wrapping sheet 13 are adjacent to each other are connected in series, so the spread (with this arrangement), these wrapping sheet envelop 13 circumferentially, wherein even after this Arrangement of the first slide portion 15A no temperature dependence is subject and hydrophobic is a nature and the second film section 15B of an existing temperature dependence subject and is a nature hydrophilic.

In the assumed case, the symmetric membrane would then, for example, the first Film portion 15A exposed under low temperature impact is also a nature hydrophobic and could implement an increased water transport, whereas the symmetric membrane of natured second film portion 15B lying hydrophobic under the influence of high temperatures is working.

On the other hand, if those symmetric membrane of the wrapping sheet 13 has the ability, under the influence of high temperatures to show an increased water transport and under the Influence lower temperatures reduced, would be yet another version of symmetrical film construction feasible.

completeness is complemented sake, that the possibility could be considered that the first and / or second foil region 15A, 15B different from a plurality of film layers Sheet material is laminated, as will be seen from the Figures 8 to eleventh

This prefix information be deepened as to what the first film section 15A with a pore-free foil material, preferably from silicone or a foil material with similar Properties, is realized. Thus, at that the third wrapping film 13, which is a nature hydrophobic, distributed over the foil envelope 5 under the influence of low temperature no or very small Pores and formed under the influence of high temperatures have larger pores that no liquid permeiren blank.

With another embodiment, it is proposed according to the model of Fig. 4 that the first Film section 15A of the third circumferential cover 13 adventitious a hygroscopic layer 14 is coated. This hygros-copic layer 14 should with highly hygroscopic substances, preferably various silicon dioxide compounds or a glycerine, can be realized. The Silica compounds are porous natured, which are realized, for example, with a silica gel.

Also added that the third sheath film 13 or the first film portion 15A with a hydrophobic properties-converting film material is realized, preferably with a "Poly (2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxole) [PDD] / PTFE" is realized.

Besides explained outset and known from DE 198 49 696 A1 use different membrane films, which are combined by lamination, etc. to form a film, can also different sheet materials such as exemplified with different physical and chemical properties are combined. For this purpose, the Unhüllungsfolien 15A, 15B of the insulation package 1 along the lines of Fig. 2 be structured as follows. The outward facing to the aircraft structure membrane with that first sheath film 15A must hydrophobic be (water repellent) and do not require a temperature dependence.

This measure is, for example, non-porous silicone membranes or membranes with like properties obtained. This first sheath film 15A film may, but need not, from different layers.

The second sheath film 15B, which shows along the lines of Fig. 2 to the cabin side, should be hydrophobic and have a temperature-dependent water transport, where at lower Temperatures increased water transport will take place.

The mass transfer through such membranes can with the so-called "Surface-flow" or Capillary condensation are described. The lower the (film influences) temperatures, the better can condense a gas. In addition, the mass transport of the condensed phase through a pore larger than that of a gaseous, because the molecular density of the condensed phase is greater than that of gaseous. Therefore, this transport mechanism is at lower Temperatures greater than at higher.

In addition to the phase state of the transported material, the mass transport also depends on the Concentration gradient across the membrane from. According to the example of FIG. 3, a substance is always from high to low potential transported. This is hereinafter referred to by the chemical Potential of the water described. To this extent the chemical potential of the water has on the Insulating facing side of the cabin (aircraft cabin) oriented film (second Wrapping foil 15B) to be very much larger than the chemical potential in the cabin, so that the Water is transported out of the insulation package. 1

This can be achieved with a view of the insulation assembly 10 of FIG. 4 in that which the insulating material facing side of the cabin-oriented film (second sheath film 15B - Is coated with a highly hygroscopic material - along the lines of FIG. 2. The accumulate hygroscopic material is water, thereby increasing the chemical potential can. Moreover, due to the highly hygroscopic material, the water the insulating material withdrawn and transported to the film to release the water. Hygroscopic substances for example, silica (porous silica compounds) or glycerol.

The following remarks are appropriate in the particular film or membrane materials bschreiben used for insulation packages in an airplane or any other vehicles. That called an insulation package product will subsequently, prefixed as in Versions also used conceptually, an insulation structure 10 (folienumhülltes insulation package 1) refer, in order to prevent any possible misunderstanding.

Also get a better understanding of the following information, the following Aspects that are related to the aircraft, taken up.

The isolation systems currently used in passenger aircraft for on the structure side contained primary insulation consisting essentially of a core material and a simple Wrapping foil. The films conventionally used generally have the task that to protect nuclear material of the insulation system from water ingress. In addition, the sheath serves to fasten the part to the bulky core material. The Enclosure is typically designed so that it is as light as possible. The disadvantage here is that by the diffusion of water vapor due to the relatively thin sheet of water vapor in the insulation package 1 penetration. In this part, the vapor condenses in the insulation package. In addition, get over Leaks in the insulation package 1 or the corresponding wrapping sheet repeatedly liquid Water in the insulation package. 1

The consequence of such a considered arrangement will be that the condensation in the insulation package 1 leads to accumulate liquid water in the insulation. It comes through Water accumulation in undesired weight gain of the insulation system, For example, a commercial aircraft, and therefore to an unnecessary increase of Take-off weight.

In contrast, for the benefit of those aircraft solutions submitted that and in Figures 1 2 are shown and previously presented. From these Figures 1 and 2, the desired water transport through the insulation packages 1 clearly with the (initially specified and again verdeutlichten) disadvantages of those traditionally used solutions are parked. So is the water transport in the Fig. 1 or by a insulation package 1 with different films 11, 12 Membranes indicated on the side of the aircraft outer skin and to the aircraft cabin. Hereinafter is that the film / membrane, which faces the aircraft outer skin, "outer sheet" and the film / membrane, called the cab shows out "inner sheet". During the flight of an aircraft shall now get as little water to the aircraft structure and there lead to condensation. For this purpose, the water transport through the outer sheet must be extremely low and also the Water transport through the inner film to be greatly reduced to the accumulation of water to avoid the insulation package. At the bottom is the water between the insulation and the structure are removed, to avoid accumulation. In addition to moisture, which in Insulating material is trapped, can be removed at the bottom unhindered.

These existing problems, it is, with appropriate solutions remedy that just at a Widebody aircraft are not negligible. Films or membranes which serve this purpose, for example, consist of the following materials: "Silicone, polydimethylsiloxane, polyethylene, Poly (cis-1,4-butadiene), poly (cis-1,4-methylbutadiene), nylon 6 (polyamide), polyimides, cellulose nitrate, Cellulose esters, Polyethylentherephterat, polymethylmethacrylate, Nafion, on 6-FDA based Materials, polyacrylonitrile, polycarbonate, polysulfone, poly (ether imide), polyether sulfone, Polyvinylidene fluoride, polypropylene, PTMSP (poly (I-Itrimethyl silyl propyne), or poly 2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxoles abbreviated PDD / [PTFE Polytedrafluorethylen]. The last two Materials show a greater mass flow through the membrane with increasing temperature, which be back close to a large free volume in the Ploymermatrix. The temperature dependence is a change in the transport mechanisms described in Fig. 5 and by the Change in the pore structure caused, which are shown in Fig. 6.

Thereby, the water transport is through the outer film because of the low temperature of the restricted structure (about 20 "C). The materials used can gummy, amorphous, semi-crystalline, or crystalline. Transport through amorphous layers is based on the solution - Diffusion - model. To a better removal of liquid water between the outer to ensure the film and the structure may contain placeholders between the insulation package 1 and the Structure to be installed, or the insulation packages can be installed under tension, so that it does not extensively applied to the structure. These structural measures then come to Used when the risk of water accumulation between the insulation and the structure or Cabin lining is.

The inner film may be like that described above is made from the same materials. Also can be used woven, hydrophobic material which liquid water restrains and allows water vapor to pass.

Those listed membranes / films may be symmetrical or asymmetrical. Symmetric membranes / films, which are shown in FIG. 7, consisting of a film or Membrane having the same properties throughout its thickness. Asymmetric membranes are made of two or more layers of the same material or different materials with different properties, such as - as shown in the Fig. 8 - with different porosities, or - as shown in the Fig. 9 - with different chemical properties. The individual layers of asymmetric membranes can be prepared by various processes, such as gluing, welding, lamination, "dip coating" Polymerization, plasma polymerization or "casting" are interconnected. Also, a gap for example less than 10 mm thickness, of following the example of Figures 10 and 11 is taken into account can be realized between the individual layers in order to continuously dissipate moisture. A gap of about 10 mm will be used only if with liquid water is expected to allow an unimpeded drainage.

The distance between the films or membranes is realized by placeholders, which in the called membrane technology "spacer".

An application example of the one shown in FIG. 1 as insulation package 1 can therefore look like this. The inner film, for example, a woven PTFE or [PDD] / PTFE] be. This material allows only water vapor and permits Pressure equalization between the aircraft cabin and the foil-welded Insulating material. The outer film consists for example of a silicone-laminated fabrics, is water-resistant, tear-resistant and chemical resistant.

Another application example of the arrangement of FIG. 2 with two identical films / membranes for an inner and outer foil could be as follows. The outer film consists of a hydrophilic structure side and a hydrophobic side of the cabin.

At low temperatures the fly of water transport is through the hydrophobic layer for example, from [PDD] / PTFE very low. Other hydrophobic materials include Polyvinylidene fluoride, Polyethylenthereph-man of letters, and polypropylene. Hydrophilic materials are for example, cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyetherimide, polyimide, Polyamide. At the bottom, the liquid water that accumulates on the structure of the hydrophilic added layer to create the water vapor partial pressure (chemical potential) on the Structure of the outer foil increases. The larger chemical potential and the higher Temperature of the water vapor transport is supported by the hydrophobic membrane. The inner Film has the same orientation as the outer by the same functionalities.

In certain cases in which the insulating material, the cabin or the structure permanently dried must be other arrangements of the films / membranes are possible. Stratification can seen from the outside as follows be designed:<sl><li>a) hydrophobic-hyrophil / insulation / hydrophilic-hydrophobic (wet insulation mat)</li><li>b) hydrophobic-hyrophil / insulation / hydrophobic-hydrophilic (drying the cabin). Just as the choice of materials with specific chemical properties similar Effects are also achieved with materials of different porosity. An example would be the Drying the structure, with an observed from the outside inwards arrangement:</li><li>c) Porous-microporous (tight) / insulation / porous-microporous (tight)</li></sl>can be achieved. The number of layers having different properties is desired.

In this context, the porosity of the films are defined as follows: <tables><table><tgroup cols="2"><tbody><row><entry align="left">Average pore diameter</entry><entry align="left">definition</entry></row><row><entry align="left">&gt; 0.1 microns</entry><entry align="left">macroporous</entry></row><row><entry align="left">5 nm</entry><entry align="left">mesoporous</entry></row><row><entry align="left">1 nm</entry><entry align="left">microporous</entry></row><row><entry align="left">&lt;1 nm</entry><entry align="left">tight.</entry></row></tbody></tgroup></table></tables>

should order to reduce cost and weight and to allow maximum flows and the dense microporous layers in the range of 0.1 to be as thin as possible 0.5 microns. The dimensions of the supporting, porous sheets are 150 microns in the range between 10 to.

To the water storage capacity of the insulation material and thus the removal continues improve the insulation material must be hydrophobic to the accumulation of liquid water to minimize capillary effects. Capillary effects are the main cause of the contamination of Insulation with liquid water. Another proposal includes the Replace the drainage holes in the Isolierpaketen 1. To Understanding it is mentioned that conventional insulation packages corresponding to the package base require drainage holes that both the pressure equalization and the drainage of liquid to allow water from the package. An alternative to these is the traditional holes Consideration of film / membrane material that liquid water will not let that happen; but has large pores that can pass water vapor on the ground at higher temperatures. Such a so-called insulating mat is shown in FIG. 12. The outer film used has a very large transport resistance to water in all states of aggregation. The considered inner film is designed in two parts. An upper part of this film is, for example, as designed the outer film, the lower part of the inner foil is of a hydrophobic, porous generated water vapor permeable material.

The porosity and the surface of the lower portion of the inner film is sufficient for the to ensure pressure equalization and possible liquid water from the inside of the lower portion remove the insulation package. In certain cases, the permeable portion of the insulation also be integrated on the top side or in the outer foil, for example, water from the dissipate Isolierpaketen for ventilated structure side, or dehumidify insulation blankets that due the installation position no drainage holes or ventilation faces at the lower end of the packet allow.

These different films may be welded together, glued, laminated or polymerized will. Moreover, it is conceivable that the water vapor permeable area of ​​the sheet through high-energy radiation ( "grafting") with possible subsequent chemical treatment or is achieved by other chemical and physical treatment methods.

These supplemented insulation assemblies, the following advantages will result, according to which<ul><li>less water vapor will enter the insulation package, so that even less condensation in Insulation package is present;</li><li>Condensation, which has once accumulated in the insulation package, from the insulation in the form can escape of water vapor or liquid water;</li><li>the insulation package can thus dry more easily;</li><li>it can no longer come to the accumulation of condensed water in the insulation ;.</li><li>in that less water is present in the insulation, the life of will increase the isolation system;</li><li>Saves weight in the aircraft, which will increase the performance of the passenger aircraft;</li><li>simply implement the measure without developing a new aircraft in aircraft leaves, and therefore worthwhile for the retrofitting of in-service aircraft located can be.</li></ul>

If the insert is provided by a drying system in the vehicle to (in general) the to dry the vehicle structure, the presented insulation structure for an insulation system could, for example, that a commercial aircraft, to be as effective as necessary and useful.

numeral

<dl tsize="3" compact="compact"><dt>1</dt><dd>insulation package</dd><dt>5</dt><dd>film wrap</dd><dt>7</dt><dd>clearance</dd><dt>10</dt><dd>insulation structure</dd><dt>11</dt><dd>first wrapping film</dd><dt>12</dt><dd>second wrapping film</dd><dt>13</dt><dd>third wrapping film</dd><dt>14</dt><dd>hygroscopic layer</dd><dt>15A</dt><dd>First slide area</dd><dt>15B</dt><dd>second film section</dd></dl>