Abstract:
A ventilation system for an avionics bay has two strut assemblies for stiffening the floor of the cockpit, each strut assembly being arranged symmetrically regarding to the central plane of the aircraft, and means of distribution of the blowing air in the cabinets of the bay from the strut assemblies. The extraction circuit includes exhaust ducts integrated in the cabinets and couples together by tight inter-cabinets junctions in an overall configuration of maximized compactness.

Description:
FIELD OF THE INVENTION 
     The present invention relates to ventilation systems of an avionics bay of an aircraft, in particular to the blowing and extraction air circuits for such system. 
     The invention generally applies to aircrafts provided with an avionics bay grouping together electric and electronic material as cabinets integrating electric cores, calculators and/or other electronic equipment (converters, etc.) and/or modules pertaining to the electric/electronic equipment, such as power modules, batteries, inertial units, etc. Electric harnesses being coupled to such bay allow this material to be connected to the functional or operational devices being concerned via the on-board network. 
     In operation, such material dissipates heat. The field of the invention relates to the continuous cooling of such material through transfer of the heat being dissipated. In the present disclosure, the expression “avionics bay” is not restrained to airplanes, but can apply to any type of aircraft or other transport means comprising a piloting cockpit. 
     BACKGROUND OF THE INVENTION 
     Up to now, the avionics bay is arranged in the bay located under the floor structure of the cockpit and in part in the cargo bay located under the passenger cabin. The expression “avionics bay” means in the present disclosure the whole electric and electronic cabinets above mentioned. 
     Now, because of the increase of the electric equipment, the cooling of the avionics bay is made, as schematically illustrated on  FIG. 1 , by a set of two independent circuits comprising: a blowing circuit C 1  consisting in an air blowing inlet pipe K 1  (arrow Fa) in each cabinet B by coupling with individual channels I 1  (arrows Fb), the air then circulating in each cabinet (arrow Fc), and an extraction air C 2  for the air having crossed the cabinet B, consisting in individual air extraction channels I 2  (arrows Fd) coupled with an outlet extraction pipe K 2  (arrow Fe). There are a blowing circuit C 1  and an extraction circuit C 2  for each of the sides of the airplane. Such circuits are duplicated for safety reasons. 
     Such circuits pose problems in terms of installation due to the complexity of their shape because of the small volume available. Moreover, in the cargo bay, the integration of the electric/electronic material is also problematic because this area is not secured. The separation to be observed between the redundant systems (cabinets, electric ways, air circuits, etc.) is restricting. 
     Thus, it has been proposed to integrate the whole avionics bay function into the secured area in front of the aircraft, comprising the cockpit, the front cargo bay and the floor structure between them. 
     However, the problem of the congestion is then posed abruptly, since such secured front area, in particular the cockpit, is already well filled with the whole equipment and apparatus thereof. The usual blowing and extraction means, consisting in tubes with a strong diameter being interconnected, are now made in a composite material of a weak thickness which can be “worked” for a better integration. Nevertheless, these means present installation constraints being difficult to manage due to the complexity and the volume thereof, as well as through their fragile construction in a light and thin material (in general a composite material). 
     BRIEF SUMMARY OF THE INVENTION 
     The embodiments of the present invention overcome at least some of the drawbacks linked to such installation constraints with a multifunctional approach for the operational components of the avionics bay and of the structural parts of a floor, substantially in their initial volume. Moreover, the embodiments of the present provide gains in terms of mass and cost by reducing the number of parts and making an integration of the system. 
     The embodiments of the present invention are applicable in particular to the floor structure of an aircraft cockpit, which is a privileged secured space, the structural volume of the floor then separating the cockpit from the front tip bay. The floor of other areas of the aircraft can also be used, in particular, the one of the dedicated passage areas (galley, toilets, etc.) forward, backward and sometimes in the central part of the passenger cabin. 
     More precisely, an aspect of the present invention provides a ventilation system for an electronic bay being integrated into an aircraft, comprising at least one cabinet, the system comprising a blowing circuit and an extraction circuit. In such a system, the blowing circuit comprises at least one strut assembly integrated into a floor intended for the aircraft and air distribution means between the cabinet(s) and the strut assembly or assemblies. And the extraction circuit comprises at least one air transmission conduct integrated into at least one cabinet. 
     According to a more particular ventilation system, the blowing circuit comprises said at least one strut assembly integrated into the floor intended for the aircraft and said air distribution means, and the extraction circuit comprises said at least one air transmission conduct. 
     The embodiments of the present invention also provide a blowing circuit for an avionics bay integrated into an aircraft and comprising at least one cabinet. Such above mentioned particular ventilation system circuit comprises at least one floor stiffening strut assembly. The circuit also comprises blowing air distribution means in said cabinet(s) of the bay from such strut assembly or assemblies. 
     According to advantageous features, the circuit comprises a double strut assembly, each strut assembly being symmetrically arranged with respect to each other according to a longitudinal plane of symmetry. Each strut assembly comprises traversal walls, an upper wall and a lower wall, at least one transversal wall possessing connecting means with fresh air transmission means. Furthermore, in at least one lateral wall, within its lid-forming upper wall and/or within its lower wall, each strut assembly can be provided with air distribution orifices being adapted to channel air blowing flows so as to ventilate the avionics cabinet being arranged the closest. 
     According to preferred embodiments:
         connection manifolds connect at least one orifice of each strut assembly to the fresh air transmission means;   partitions being internal to each strut assembly formed in parallel to the connection side with the fresh air transmission means also have orifices aligned on those of the connection wall;   the air distribution orifices are provided with adjustable diaphragms adapted to provide a sealing junction and a regulation of the blowing flows;   the lower wall of each strut assembly is tilted so that the strut assembly presents an evolutive section to provide a drainage of the ventilation air condensation waters;   openings are arranged in the partitions of each strut assembly to provide the circulation of the drained water;   a sealing resin is deposited on each strut assembly so as to increase sealing.       

     According to an embodiment of the invention, an air extraction circuit of an avionics bay integrated into an aircraft, comprising at least one cabinet, may consist in the above mentioned blowing circuit. In such an air extraction circuit, the direction of the air flow is inverted so that such inverted air flows, the air distribution means and/or the air transmission means are dedicated to the extraction. 
     An embodiment of the invention also relates to an extraction circuit of an avionics bay integrated into an aircraft, comprising at least one cabinet, in particular an aircraft cockpit. Such particular ventilation system extraction circuit, as defined above, comprises transmission conducts integrated into the cabinets and dedicated to the inter-cabinets air transmission so as to provide an overall configuration of a maximized compactness. 
     According to some preferred embodiments:
         sleeves combined with connection parts make the sealing junction of the extraction circuit;   the cabinets to be ventilated being formed by strut assemblies consisting in walls, air transmission parallelepiped conducts are formed on at least one substantially horizontal and/or vertical wall of the cabinets in order to at least partially meet such wall; these conducts provide extraction spaces integrated into the cabinets, wherein the air flows circulate after making a thermal exchange in the cabinet;   the cabinets constitute in the top part extraction collectors towards the air transmission conduct or a connection sleeve.       

     According to an embodiment of the invention, a blowing circuit of an avionics bay integrated into aircraft comprising at least one cabinet can also consist in the extraction circuit as mentioned above. In such blowing circuit wherein the direction of the air flows is inverted so that the air transmission conducts integrated into the cabinets, the air flows and/or the collectors are dedicated to blowing. 
     An embodiment of the invention also relates to a ventilation system of the type defined above with a blowing circuit consisting in the extraction circuit as defined above, wherein the direction of the airflows is inverted so that the air transmission conducts integrated into the cabinets, the air flows and/or the collectors are dedicated to blowing. In such a system, the extraction circuit consists in the circuit as defined above, wherein the direction of the airflows is also inverted so that such air flows, the air distribution means and/or the air transmission means are dedicated to the extraction. 
     An embodiment of the invention also relates to an avionics bay comprising cabinets and integrating an air transmission circuit which is adapted to serve as an extraction circuit and a blowing circuit for the above mentioned ventilation system. Such transmission circuit comprises air transmission conducts integrated into the cabinets and dedicated to the inter-cabinets air transmission so as to provide an overall configuration of a maximized compactness. The cabinets are then arranged the closest to each other so that the inter-cabinets conducts and sleeves present a minimal congestion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other data, characteristics and advantages of the present invention will appear upon reading the non limitative description which follows referring to the accompanying figures, wherein, respectively: 
         FIG. 1  represents a ventilation schema for cabinets through a set of circuits and pipes according to the state of the art (already discussed); 
         FIG. 2  represents two principle schemas showing the position of the avionics bay before (schema  2   a ) and after (schema  2   b ) its integration into the secured area; 
         FIG. 3  is a simplified perspective view of an aircraft cockpit architecture integrating side blowing strut assemblies; 
         FIG. 4  is a perspective view of an avionics bay equipped with blowing and extraction means according to an embodiment of the invention; 
         FIGS. 5   a  and  5   c  are perspective views ( FIGS. 5   a  and  5   b ) and a sectional view ( FIG. 5   c ) of an exemplary blowing strut assembly according to an embodiment of the invention; and 
         FIG. 6  is a sectional schematic view of the cabinets in an avionics bay integrating extraction means according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the present description, the terms “forward”, “backward”, “front”, “rear” “under”, “upper”, “lower”, “lateral”, “transversal”, “internal”, “external”, “vertical”, “horizontal’, and the derivatives or equivalents thereof relate to relative positionings for elements in a standard configuration of an airplane lying on the ground and with respect to a longitudinal plane of symmetry being vertical in this configuration. 
     Referring to the principle schema of  FIG. 2 , the installation of the avionics bay  1  in an airplane  2  is conventionally distributed (schema  2   a ) between a part  20  of the cargo area  21 —located under the passenger cabin  22  in a non secured area Z 2 —and the front bay  23  located under the cockpit  24  in a secured area Z 1 . According to an embodiment of the invention (schema  2   b ), the avionics bay  1  is partially displaced so as to come totally in the secured area Z 1  forward of the airplane  2  through a distribution of the bay between the front bay  23  and the cockpit  24 . 
     Preferably, the avionics bay is installed for most of it in the cockpit—for example over 80% and more—as illustrated below. 
     The simplified view of cockpit architecture  24  on  FIG. 3  shows the lateral strut assemblies  31  and  32  through which the fresh air transits before blowing in the avionics bay. Such strut assemblies  31  and  32  are arranged symmetrically with respect to the longitudinal symmetry plane PI and let a central volume  3  being free to be able to accommodate a cabinet of the avionics bay (see detailed description above). 
     The strut assemblies  31  and  32  have transversal internal partitions  33 . These partitions  33 , the internal longitudinal walls  311  and  321 , respectively, of the strut assemblies  31  and  32 , as well as the rear transversal walls  313  and  323  of such strut assemblies, are perforated with respective orifices  34   c ,  34 ,  34 ′ and  34 ″ so as to provide an air blowing. These partitions  33  and the walls  311 ,  321 ,  313  and  323  are vertical. 
     Referring to  FIG. 4 , the blowing and extraction means of an avionics bay consisting in cabinets  51  to  55  (represented in transparency for a better visibility on the figure) are partially illustrated so as not to overload the figure. These cabinets are arranged in the cockpit  24  as compactly as possible so as to bring them closer at a maximum to define well integrated extraction conducts, with thus a compactness being maximized, and furthermore to gain space. Thus, in the illustrated example, the cabinets  55 ,  51  and  52  are arranged substantially juxtaposed from the less high to the higher from the front to the rear of the cockpit  24 . The cabinet  54  is centrally offset in the cockpit and tilted on the floor  5  of the cockpit. The cabinet  53  is arranged in the central volume  3  made free in the walking floor  5  of the cockpit. Other equivalent cabinets, being not represented, can be arranged symmetrically with respect to the longitudinal plane PI. 
     The blowing fresh air comes from air distribution sealing manifolds  41  to  44  coming from the main tube  40 . The manifolds  41  to  43  are connected to the air inlet orifices  34 ′ in the strut assemblies  31  and  32 . The air then crosses the cabinets  51  to  55 , is submitted to thermal exchanges upon such crossings so as to extract the calories being present, and then is evacuated from the cabinets via an extraction tube  10 . 
     As illustrated in reference to the strut assembly  31 , the blown air (arrows F 1 ) entering such strut assembly is re-directed towards the cabinets  51  to  55  of the avionics bay, either directly—through the orifices  34 ″ and  35  arranged respectively in the internal longitudinal walls  311 ,  321  and in horizontal lids  36  and  37  of the strut assemblies for the cabinets  53  and  51 —, or through the orifices  34  of the front transversal walls  314 ,  324  of the strut assemblies, in connection with sleeves  45  to  48 . The sleeves  45  to  47  connect the strut assembly  31  to the cabinet  55 , and the sleeve  48  connects the cabinets  55  and  54  so as to provide air blowing in these cabinets (horizontal arrows F 2  and vertical arrow F 3 ). The external longitudinal walls  312  and  322  of the strut assemblies  31  and  32  consist in portions of the fuselage which thus closes the strut assemblies. 
     The strut assembly  31  is illustrated more precisely referring to  FIGS. 5   a  to  5   c  by perspective views (being lateral on  FIG. 5   a  and underside on  FIG. 5   b ) and a section view ( FIG. 5   c ). 
     On such  FIGS. 5   a  to  5   c  are represented the fresh air distribution manifolds  41  and  42 , the fresh air transfer sleeves  45  to  47 , the horizontal air passage orifices  35  arranged in the lid  36  and the vertical ones  34 ,  34 ′,  34 ″,  34   c  respectively arranged in the front ( 314 ) and rear ( 313 ) transversal walls, in the internal longitudinal wall  311  and in the partitions  33 . The air distributions orifices  34 ,  34 ′,  34 ″ and  35  are provided with adjustable sealing diaphragms  3  to allow the air flow to be regulated. The external longitudinal wall  312  has no air passage orifice. 
     The transfer sleeves  45  to  47  are also connected via adjustable diaphragms  3  to the orifices  35  arranged in the bottom wall  550  of the partially represented cabinet  55 . 
     The section view according to  FIG. 5   c  highlights the decreasing section of the strut assembly  31  in the longitudinal extension thereof. The bottom wall  310  of such strut assembly is tilted so that the transversal walls  313  and  314  present a height being just higher than the diameter of the orifices  34  and  34 ′, the diameter of the orifices  34 ′ being substantially higher than the one of the orifices  34 . 
     Such tilted configuration of the strut assemblies allows the condensation waters from the ventilation air to be drained. Very fine openings  39  are made in the partitions to provide the circulation of the drain water. Moreover, the tilting of the strut assemblies is regulated to adjust their height as a function of the ventilation need. 
     Furthermore, the fresh air being blown in the cabinets  51  to  55  is extracted from these cabinets, as illustrated by the perspective view of  FIG. 4  and the section view of  FIG. 6 . The extraction circuit consists in connection sleeves  11  between the cabinets, here between the cabinets  54  and  55 , in adjacent air circulation conducts, here E 1 , E 2 , E 5 , integrated into the cabinets  51 ,  52  and  55  and in the final air extraction tube  10  outside the cockpit. 
     The adjacent circulation conducts E 5 , E 1  and E 2  each limit a parallelepiped extraction space by two parallel main walls, one of which consist in a wall forming at least in part a wall of the cabinet, here the cabinets  51 ,  52  and  55 . 
     In particular, the extraction conduct E 5  is restrained by a rectangle parallelepiped, the main wall A 5   h  is parallel to the horizontal upper wall  551  of the cabinet  55 . The extraction conducts E 1  and E 2  globally define two half-spaces being “perpendicular” between them E 1   v  and E 1   h , E 2   v  and E 2   h . The “perpendicular” half-spaces of each extraction space are perpendicular, since they are limited by perpendicular walls, respectively, A 1   v  and A 1   h  or A 2   v  and A 2   h.    
     Moreover, each extraction space wall may consist in several parallel walls to accommodate the architecture of the cabinets: for example, the wall A 2   v  consists in walls  2 V 1  and  2 V 2  so as to extract the air coming not only from the space E 1 , but also from the strut assembly  53 . 
     Furthermore, inter-cabinets sealing junctions J 1  to J 3  and the connecting junction J 4  between the extraction space E 2  and the final extraction tube are arranged to connect the extraction conduct, respectively E 5  and E 1 , E 1  and E 2  as well as E 3  and E 2 , and form a continuous extraction circuit. 
     Because the hot air goes up, the successive positioning of the extraction spaces is horizontal and/or vertical ascending. The air extraction then occurs by following the vertical ascending path according to the arrows F 4  in the cabinets  51  to  55  as well according to ascendant (arrows F 5 ) and horizontal (arrows F 6 ) vertical paths in the extraction spaces, namely: the horizontal extraction sleeve  11  of the cabinet  54 , in the horizontal extraction conduct E 5  of the cabinet  55 , in the vertical extraction half-space E 1   v  and the horizontal half-space A 1   h  of the cabinet  51 , as well as in the vertical half-space A 2   v  and the horizontal half-space E 2   h  of the cabinet  52 . 
     The upper part of the cabinets  51  to  55  consists in hot air extraction collectors  61  to  65  (arrows F 7 ) in connection with the adjacent extraction spaces: the connecting sleeve  11  for the cabinet  54 , the space E 5  for the cabinet  55 , the half-space E 2   v  for the cabinet  53  and the half-spaces E 1   h  and E 2   h  for the cabinets  51  and  52 . 
     The invention is not limited to the exemplary embodiments being described and represented. Thus, the strut assemblies  31  and  32  can also serve as a walking floor  5  for the cockpit  24 . Furthermore, these strut assemblies can also contribute for the most part to the cooling of other equipment and apparatus of the cockpit through openings arranged on their upper wall or on their lower wall for cooling the material located within the lower part (front or cargo bay). 
     Further, each cabinet can integrate more than two extraction spaces, for example on each external side (i.e. maximum six spaces for a parallelepiped cabinet). Moreover, the extraction spaces can be provided inside the cabinet (first category) or outside the initial cabinet (second category). In this last case, the final cabinet integrates the extraction spaces. In the above illustrated exemplary embodiment, the cabinet  55  belongs to the first category and the cabinets  51  and  52  to the second one. 
     Moreover, the blowing and extraction circuit and the means which constitute them can be inverted in their function by inverting the direction of the air flows: the blowing can be operated “from the top” from the extraction devise which then serves as a fresh air supplier and the extraction spaces become blowing spaces, whereas the extraction is made “from the bottom” and the evacuation of hot air is made by the air supplying manifolds. 
     The invention can apply to any transport structure: airplane, helicopter, locomotive, ship, etc. The term “avionics” is then to be adapted as a function of the structure (railway, naval, etc.).