EP2259847B1 - Arrangement for providing active fire protection in aircraft - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to a device for active fire protection in aircraft by means of at least one protective shield.

BACKGROUND OF THE INVENTION

Intumescent materials for fire protection are generally formed with a conventional organic plastic material and other additives. In case of fire, the intumescent material foams to an inorganic, non or hardly combustible material, whereupon the fire retardant effect of the intumescent substances is based.

Such intumescent materials can be produced, for example, with a polyurethane mixed with expandable graphite, the expandable graphite multiplying its volume in case of fire. Alternatively, intumescent materials can be produced on the basis of epoxy resins, which are provided with additives whose volume increases by heat effect many times compared to the initial state.

This makes it possible, for example, from the cargo space leading into the passenger compartment lines automatically fire in case of fire from the inside, so that the combustion gases can not get from the cargo compartment into the passenger cabin. That the Expanded graphite enclosing polyurethane is substantially completely thermally decomposed by the action of heat. As a result of the fire, the intumescent material is completely "carbonized" and thus forms a plastic-free, inorganic material that is capable of, for example, a fire-retardant line and to close against the passage of flue gases. A suitable for incorporation into the polyurethane intumescent material is that known under the trade designation "BayGraphit ^®" material to provide examples.

Instead of polyurethane and silicone foam plastics and / or polyimide foam plastics can be used to create the intumescent material. In the case of the use of silicone foam plastics or of polyimide foam plastics, these are generally not equipped with an expandable graphite. In this different composition in general is another intumescent component, such as the well-known under the brand name "vermiculite ^®" material added to achieve the desired flame-retardant effect. Furthermore, thermoplastic or thermosetting plastics can be used with embedded intumescent under the action of heat substances, such as expanded graphite or "vermiculite ^® ". Furthermore, elastomers can also have intumescent properties. An example of this is the rubber compound "FS195" from 3M ^® , which is mixed with sodium silicate beads.

Due to the coarseness of the expandable graphite or vermiculite ^® additions, these are generally not suitable as functional fillers for the production of intumescent coating materials, such as, for example, paints or coatings. In this case, mixtures of colloidal silicic acids, aluminum oxides, aluminum hydrates, aluminum silicates and further metal oxides are preferably used as intumescent additives. The use of these aggregates will increase the production of Almost homogeneous, intumescent coatings with low material thicknesses for the protection of components against the effects of fire possible.

All of the compositions mentioned above have in common that the desired intumescent reactions in the event of fire only begin at a certain material-specific initial temperature. On the one hand, however, this initial temperature must not be too low, so that no unwanted intumescent reaction occurs in the region of the normal operating temperatures of the aircraft. On the other hand, the initial temperature must not be too high to ensure a sufficiently fast and reliable response in case of fire and thus to effect a safe fire or flue gas suppression. In order to meet these requirements, it is usually attempted to set an initial temperature of the intumescent substances in the order of 250 ° C.

For many components, for example components made of temperature-sensitive materials or firebox, however, a controlled intumescence at a relatively low temperature, which is only slightly above the maximum permissible operating temperature of the aircraft, is desirable. At present, however, no components or rooms can be sealed in this way in case of fire against each other, since today's intumescent materials at an ambient temperature in the range of 100 ° C still show no reliable foaming reaction.

DE 203 17 181 U1 describes a gasket for fire protection purposes with at least one intumescent material which foams when exposed to heat, and with a foaming initiated agent, wherein the means is at least one disposed on at least one outer surface of the intumescent material first electric heat generator.

Out GB 2 107 183 A is a grid known, which can be placed in ventilation shafts and openings. This grid has an intumescent coating that can close the plurality of openings in the grid when exposed to heat during a fire.

The object of the invention is therefore to provide a device for active fire protection in aircraft, in which a fire protection by controlled intumescence at a temperature of significantly less than 250 ° C is possible.

This object is achieved by a device having the features of patent claim 1.

Characterized in that the at least one protective shield is formed with an intumescent material which can be activated in the event of fire by means of an electrical heating device, in particular can be foamed,
results in a good and above all controllable fire protection effect in a relatively low temperature range of 100 ° C to about 150 ° C, which is well below the required for triggering the intumescent reaction initial temperature of about 250 ° C. The protective shield according to the invention can equally serve as an inner seal in pipelines or as an at least regionally effective surface protection of components within the aircraft.

According to an advantageous embodiment, at least one temperature sensor is connected to a control and regulation device in order to monitor a temperature in a fire area.

As a result of this embodiment, it is possible to set a limit temperature in the fire area, from which the heater caused by the controlled foaming of the formed with an intumescent protective shield, preferably continuously in a wide temperature range. In this case, it is usually not necessary to provide additional temperature sensor for the active fire protection device.

Rather, the necessary anyway for the function of the fire fighting equipment in the aircraft, preferably arranged in the cargo area, temperature sensors can be used in an advantageous manner. In this case, when the automatic fire extinguishing device is triggered in the cargo compartment, the foaming or activation of the intumescent material is simultaneously initiated by the switching on of the electric heating device. For separate trip times, however, separate temperature sensors must be present.

According to a further advantageous embodiment, it is provided that the electric heater is turned on in a temperature interval of 90 ° C up to 150 ° C by means of the control and regulating device to initiate the controlled foaming of the intumescent material.

This makes it possible to use for the production of at least one shield according to the invention intumescent materials that have a relatively high initial temperature of, for example, up to 250 ° C, and still the active shield in case of fire at a relatively low room temperature between 90 ° C and 150 Controlled and reliably activated by foaming.

A further development of the device provides that the intumescent material used on reaching a temperature of more than 250 ° C, in particular from a material-specific initial temperature, foams automatically. This results in a fallback position (redundancy) of the active fire protection system in the event that the electronic control and regulating device and / or the electric heater - for example, in the event of a fire-related failure of the electrical emergency power supply or the like - no longer working properly. For without prejudice to the intended controlled-defined activation or release of the shield by means of the electric heater when reaching a temperature between 90 ° C and 150 ° C in the fire area or in the cargo compartment takes place in each case when reaching or exceeding a threshold temperature (initial temperature ) of about 250 ° C, the automatic release of the intumescent protective shield by the automatic foaming of the protective shield forming intumescent material.

Furthermore, it is provided that the electrical heating device has at least one heating wire.

As a result, a structurally simple construction of the electric heater is ensured using standardized and readily available components. By feeding a sufficiently high heating current I _heating in the heating wire this is brought to the required for triggering the intumescent reaction of the coating initial temperature in a range of about 180 ° C to 220 ° C.

In addition, the usually at least limited flexible and possibly electrically insulated heating wires can be integrated in an advantageous manner in shields with a more complex geometric shape. As an example of this, a grid or a lattice-like structure is to be mentioned, which is formed at least partially with the intumescent material.

Furthermore, it is possible to produce such a grid at least partially with electrical heating wires (resistance wires), wherein the grid, including the simple, non-heatable wires, preferably completely coated with an intumescent material and disposed within a pipeline. In this way, for example, a ventilation duct between a cargo hold and a passenger cabin of an aircraft in case of fire by the active foaming of the intumescent material by means of the heating wires are gas-tight against toxic flue gases and other adverse fire effects in the form of heat radiation sealed. As a rule, such a grid, depending on a cross-sectional geometry of the pipe to be closed, will have a circular, elliptical, oval or quadrangular base. If necessary, insulating pieces should be provided at intersections of the grid to avoid short circuits between the heating wires and the other metal wires of the grid. Metal wires of the grid, which do not function as heating wires, may have to be provided with an insulating varnish in order to prevent unintentional bridging of non-insulated heating wires and thus reduced heating power.

In addition, finished metal mesh ("wire mesh" etc.) can be used, which are at least partially or partially wrapped with electrical heating wires. If necessary, such metal mesh must be provided with additional electrical insulation, for example, a phenolic insulating varnish, a dip insulation or the like to prevent uncontrolled bridging the braided, optionally electrically conductive heating wires.

Furthermore, the protective shield for pipe closure can be formed in the event of fire with a honeycomb-shaped structure whose webs and / or cell surfaces facing the cargo space are at least partially coated with an electrically conductive paste which acts as an electrical heating device. Honeycomb-shaped core structure, the webs of the ^®, for example, Nomex -paper formed are preferably continuously coated with a suitable intumescent material. In case of fire, a sufficiently high heating current I _{heating is given} by the coated with the conductive paste edges of the honeycomb core structure, whereby the intumescent material foams, swells or inflates and securely closes all chambers of the honeycomb structure against the passage of flue gases.

At a sufficiently high height of the honeycomb, for example, more than 5 cm in the direction of the longitudinal axis of the tube to be sealed, a sufficiently pressure-resistant closure in case of fire by the swollen intumescent material can be achieved.

A further development of the device provides that the electrical heating device is formed with at least one planar heating element, in particular with an electrical resistance foil or the like.

This variant of the heater can be used advantageously in particular if a substantially flat, temperature-sensitive component for fire protection at least partially coated on one or two sides with a planar shield of the intumescent material and / or covered with plates of the intumescent material and / or to be coated. In such a constellation, the planar electric heating element is embedded in and / or below the intumescent layer or in a plate made with the intumescent material, so that a full-coverage and simultaneous foaming of the protective shield in case of fire is possible. A superficial arrangement of the Flächenheizelementes on the intumescent material is disadvantageous, since the heating element is exposed directly in this case, the effect of the fire or the radiant heat.

Notwithstanding this, the planar design of the heating element allows a uniform and rapid heating of the intumescent material of the shield, whereby a uniform and rapid Aufschäumprozess is effected, which contributes to a reduction of fire damage to the components to be protected.

As a heater may also serve an electrically conductive, in particular band-shaped nonwoven, which is additionally equipped with an intumescent material. Such a nonwoven, for example a nonwoven fabric formed with electrically conductive carbon fibers or woven copper filaments, can serve, for example, for fireproof sealing of joints between sufficiently fire-resistant ceiling, wall or floor slabs within the hold of an aircraft. Preferably, such a nonwoven is formed self-adhesive, to facilitate installation on the joints or joints, and ideally, to hermetically seal all joints, openings and recesses within the hold, in addition to the sealing of the pipes against the passage of flue gases and the commonly used aerospace fire extinguishing agent Halon ^® can.

Further advantageous embodiments of the device are set forth in the further claims.

Fig. 1

Ein Schutzschild zum Verschließen einer Rohrleitung im Brandfall gegen den Durchtritt von Rauchgasen sowie eine mit einem weiteren Schutzschild geschützte Trennwand, und

Fig. 2

eine Draufsicht auf ein mit einem intumeszierenden Material gebildetes Gitter als Schutzschild zum Verschluss einer Rohrleitung (Belüftungs-bzw. Klimatisierungsleitung) gemäß Fig. 1.

In the drawing shows:

Fig. 1

A protective shield for closing a pipeline in case of fire against the passage of flue gases and a partition protected by another protective shield, and

Fig. 2

a plan view of a grid formed with an intumescent material as a shield for closing a pipe (ventilation or air conditioning line) according to Fig. 1 ,

The Fig. 1 shows an embodiment of the device for closing a pipeline, in particular a ventilation line, and for protecting a partition wall (firewall) in case of fire.

A device 1 is arranged in the region of a partition wall 2, which runs vertically between a cargo compartment 3 of an aircraft and a passenger compartment 4. In the hold 3 a fire 5 is located. The cargo space 3 is connected to the passenger compartment 4 through a pipeline 6, in particular a ventilation line, which is received in a connecting opening 7 in the partition wall 2. Air from the cargo compartment 3 is conveyed by means of a blower 8 in the direction of the arrows 9,10 in the passenger compartment 4 and this at the same time by means of a device 11th conditioned, that is, in particular, the temperature, the pressure and / or the humidity of the passenger compartment 4 supplied air is adjusted.
The device 1 comprises a temperature sensor 21 and two shields 12,13, which in the embodiment shown the Fig. 1 are configured with a plate 14 with an intumescent material to protect the partition 2 from the action of the fire 5 and as a grid 15 for sealing the pipe 6 opposite the fire 5 outgoing flue gases 16. Instead of the plate 14, the partition wall 2 may also be formed with a coating having a thickness of up to 3 mm of an intumescent material.

The grid 15 has, at least in sections, an electrical heating device 18 formed with heating wires 17 or resistance wires, the heating wires 17 and the other metal wires of the grid 15 not being designated by a reference number being at least partially coated with a suitable intumescent material, ie surrounded on all sides. The heating wires 17 of the grid 15 can also serve as grid wires.

The arranged in front of the partition wall 2 plate 14 may be completely or at least partially formed with an intumescent material in which an electric heater 19 is embedded. Alternatively, the heater 19 may also be arranged behind the plate 14.

Alternatively, a side facing the cargo compartment 3 side of the partition 2 may be at least partially provided with an intumescent coating, in or below an electric heater with the lowest possible height, especially heating wires with small cross-sections and / or a heating foil is arranged. The coating advantageously has a material thickness of less than 1 mm. The heating device 19 within the plate 14 is advantageously provided with planar heating elements 20, in particular in the form of an electrical resistance foil, meandering heating wires with short distances or the like realized.

The completely foamed in case of fire state of the coating of the grid 15 is in the Fig. 1 indicated by the irregular freehand outline (with punctured filling) greatly inflated. Accordingly unevenly foams in the event of fire, the surface facing the fire 5, not designated by a reference numeral surface of the initially completely flat plate 14 for the protection of the partition wall 2.

In the event that the partition wall 2 is formed with sufficiently fire-resistant plate elements, protection by the intumescent plate 14 or an intumescent coating is in principle not necessary. However, since the plate members usually abut each other to form joints and the cargo space boundary, the resulting joints can be covered with a band-shaped, electrically conductive nonwoven fabric as a protective shield, which is equipped or coated with an intumescent material. The electrically conductive nonwoven acts as a heater and causes the controlled-active swelling of intumescent material in contact therewith in case of fire, so that a passage of flue gases is prevented by, for example, widening due to the fire effect between the plate elements. The change in the joint width can be caused in the event of fire, inter alia, by a thermal deformation or rejection of the substructure of the partition 2.

By means of such a nonwoven fabric, the cargo compartment can be hermetically sealed against the passage of fumes in the event of fire in the event of a fire.

As a suitable intumescent material suitable for the coating of the grid 15, for example, polyurethanes or other spreadable and / or submersible plastic materials into consideration, with suitable intumescent additives such as the aforementioned colloidal silicas, alumina, aluminum hydrates, aluminum silicates or other metal oxides added are.

A merely intumescent coating for the dividing wall 2 with an electrical heating device integrated at least in some areas - without an intumescent plate 14 in front - preferably has a corresponding composition.

Alternatively, the partition 2 may be covered with intumescent nonwovens, fabrics or similar intumescent semi-finished products.

Unlike the intumescent materials mentioned above, a variety of other intumescent materials or additives may be used to make the shields 12, 13.

By the fire 5, a temperature of 100 ° C is usually reached quickly in the event of fire in the range of a temperature sensor 21 and exceeded. In this case, the heaters 18,19 are activated by a control and regulating device 22, so that both the plate 14 and the grid 15 are brought quickly to the initialization temperature of about 250 ° C and the active fire protection with respect to the partition wall. 2 and the pipe 6 is effective by the foaming of the intumescent material, although in the region of the temperature sensor 21 initially relatively low temperatures of about 100 ° C prevail. At the same time the pipe 6 is securely sealed by the intumescent coating intumescent of the grid 15 against the passage of toxic fumes 16. Furthermore, alternatively or in addition to the temperature-controlled activation a manual triggering of the heaters 18,19 be provided by the on-board staff. In this case, at least one additional actuating element, in particular an electrical switch, is preferably arranged in the region of the passenger compartment and / or in the cockpit of the aircraft.

The limit temperature at which the two heating devices 18, 19 are automatically switched on by the control and regulation device 22 is preferably infinitely adjustable in a range between 90 ° C. and 150 ° C., since the maximum permissible operating temperature of a (passenger) aircraft in the Generally at about 80 ° C. It may therefore be necessary to use temperature sensors independent of the fire-extinguishing system for triggering the heating device 18, 19.

The Fig. 2 shows a schematic plan view of a grid, which is provided for the automatic, controlled closure of pipes, in particular ventilation ducts in aircraft, in case of fire.

A grid 23 for use within a pipeline with a square, round or oval cross-section is formed with two resistance wires or electrically conductive heating wires 24,25 that are laid in a meandering manner. The preferably continuously coated with an intumescent material heating wires 24,25 form a plurality of recesses 26 for the passage of the air to be conditioned, which are not consistently provided with a reference numeral.

The two heating wires 24,25 serve as heaters to quickly heat the grid 23 in case of fire by means of a heating current I _heating up to a required for the intumescent material required initial temperature of 250 ° C, for example, the intumescent reaction of the coating of the grid 23 in run a controlled temperature range between 90 ° and 150 ° C. The intumescent coating of the grid 23 may be any suitable be formed intumescent epoxy resin or with an intumescent thermoplastic material. As a result of the intumescent reaction, the recesses 26 are closed quickly and completely by foaming or puffing and thus reliably prevents the passage of "cold" flue gases through the grid 23 in the event of fire even at relatively low temperatures.
In order to avoid short circuits between the heating wires 24,25, it is usually necessary to provide in each node of the grid 23 a high-temperature resistant electrical insulation, of which only three insulation 27 and insulating elements are provided representative of the rest with a reference numeral. Notwithstanding the shown meandering arrangement of the two heating wires 24,25 different installation forms can be chosen to cause the most uniform, effective and rapid heating of the grid 23. For example, prefabricated, commercially available metal meshes or gratings can be used, in which a sufficient number of heating wires is woven.

Wire braids coated with an intumescent material or wire mesh can be used beyond the use as a fire barrier for the fire protection of electronic components, cable bundles or piping systems (esp. Fuel lines and hydraulic lines). In this case, the relevant component or line can be bandaged or wrapped with such intumescent coated or equipped wire mesh.

By the device according to the invention an active fire protection in a tripping range between 90 ° C and 150 ° C is guaranteed with protective shields 12,13 of intumescent materials, although the initial temperatures of such materials today usually move in the order of about 250 ° C.

LIST OF REFERENCE NUMBERS

1

contraption

2

partition wall

3

Cargo hold (airplane)

4

Passenger compartment (airplane)

5

Fire

6

pipeline

7

Connection opening (partition wall)

8th

fan

9

arrow

10

arrow

11

Device (air-conditioning device)

12

shield

13

shield

14

plate

15

grid

16

flue gas

17

heating wire

18

heater

19

heater

20

planar heating element (e.g., electrical resistance foil)

21

Temperature sensor (sensor)

22

Control and regulating device

23

grid

24

heating wire

25

heating wire

26

recess

27

Insulation (insulating element)

Claims (10)

1. A device (1) for active fire protection in aircraft by means of at least one protective shield (13), which protective shield is formed with a intumescent material which, in the case of fire is activatable, in particular can be foamed,

   wherein the fire region is separated from a protective area by a partition wall (2) with at least one connection opening (7), in which connection opening the protective shield (13) is arranged to close it in case of fire, and

   wherein, in the non-activated state, the protective shield comprises a plurality of recesses (26) in the connection opening (7) for enabling passage of gases,

   characterized in that the intumescent material is activatable by means of an electrical heating apparatus (18).
2. The device (1) of claim 1, characterized in that at least one temperature sensor (21) is connected to a control and regulating device (22) in order to monitor a temperature in a fire region.
3. The device (1) of claim 2, characterized in that the electrical heating apparatus (18) can be switched on in a temperature range from 90 °C to 150 °C by means of the control and regulating device (22) in order to initiate controlled foaming of the intumescent material.
4. The device (1) of any one of claims 1 to 3, characterized in that the intumescent material self-actingly foams as of a temperature of 250 °C, in particular as of a material-specific initial temperature.
5. The device of any one of claims 1 to 4, characterized in that the electrical heating apparatus (18) comprises at least one heating wire.
6. The device (1) of any one of claims 1 to 5, characterized in that the electrical heating apparatus (18) is formed with at least one sheet-like heating element (20), in particular with an electrical resistance foil.
7. The device (1) of any one of claims 1 to 6, characterized in that the fire region is in particular a cargo compartment (3) of an aircraft, the protection region is in particular a passenger cabin (4) of an aircraft, the at least one connection opening (7) is in particular at least one pipe (6), wherein the protective shield (13) is arranged in the at least one connection opening (7) in order to close it off in a pressure-tight manner in the case of fire.
8. The device (1) of any one of claims 1 to 7, characterized in that the at least one protective shield (12) is formed with at least one panel (14) that at least in some regions is formed by the intumescent material.
9. The device (1) of any one of claims 1 to 8, characterized in that the at least one protective shield (13) is formed with at least one grid (15) that at least in some regions is coated with the intumescent material.
10. The device (1) of any one of claims 7 to 9, characterized in that at least one component in the region of the cargo compartment (3), in particular the partition wall (2) between the cargo compartment (3) and the passenger compartment (4), is coated with the intumescent material at least in some regions.

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