Field of the invention

This invention relates to an aircraft environmental control system, and in particular an aircraft environmental control system such as a dehumidifier for reducing the humidity within an aircraft, both cabin and other compartments such as an avionics compartment or the like, in order to improve the operation of components located in the enclosure or reduce the risk of faults occurring, in particular with electronic components which are generally negatively affected by the presence of moisture. The control system may also be used to modify and/or maintain other environmental conditions such as the internal temperature of one or more locations within the aircraft, for example maintaining an elevated baseline temperature in cold climates and conversely reducing the temperature in hotter climates.

Background of the invention Studies have shown that the environmental control of aircraft avionics, in particular by means of dehumidification, results in an increase in reliability of the various electrical and electronic components, with mean time between failures increased by up to 50%. Current solutions amount to temporarily locating a dehumidifier inside the relevant aircraft enclosure housing the avionics or ofrier componentry to be dehumidified. However this solution presents a risk of fire damage to the aircraft, and as a result is often not permitted by many aviation engineering managers. This solution is also cumbersome when it is necessary to remove the dehumidifier, in particular in the case of rapid response aircraft such as emergency services helicopter or aeroplane, military aircraft or the like.

An alternative solution, having particular application to the above mentioned rapid response units, is the use of external, dehumidification units which utilize mechanical fasteners to interface an air manifold to the fuselage, in particular about one or more vents leading to an enclosure to be dehumidified. The manifold, usually some form of flexible tubing, extends from the dehumidification unit and terminates in an interface unit which is then mechanically fastened to the fuselage about the vents for the duration of the dehumidification process. For maximum effect the interface unit should conform to the usually curved fuselage, in order to ensure a reasonable seal with same. As a result these interface units are generally aircraft specific and involve the use of blanks and mechanical inserts, which inhibit their use in other platforms and also involves significant cost in their manufacture and time in setting up the units. Furthermore, due to the mechanical fastening of the interface unit to the fuselage, it can take significant time to remove the unit, which is undesirable for rapid response units or the like. It is also often desirable to control other environmental conditions on the interior of an aircraft, for example in the pilot and/or passenger compartments, and particularly when operating aircraft in "harsh" environments such as where extreme temperatures are experienced. This is especially the case if operating rapid response aircraft such as emergency services helicopter or aeroplane which are likely to be used in transporting sick or injured individuals, whose comfort is of paramount importance.

The present invention has been developed to overcome the above mentioned problems of the prior art.

Summary of the invention

According to a first aspect of the present invention there is provided an aircraft environmental control system for temporary engagement with an aircraft fuselage, the system comprising an arm constrained for rotation about a pivot axis; a coupling mounted on the arm on one side of the pivot axis; and a counterweight located on an opposed side of the pivot axis.

Preferably, the coupling is adapted to mate against an aircraft fuselage.

Preferably, the coupling comprises a deformable gasket to facilitate conformity with an aircraft fuselage.

Preferably, the system is mounted on a pair of co-axial wheels. Preferably, the pivot axis is defined by the axis of rotation of the wheels.

Preferably, the system comprises an environmental control unit. Preferably, the environmental control unit comprises a dehumidification unit. Preferably, the environmental control unit comprises a temperature control unit Preferably, the environmental control unit defines the counterweight.

Preferably, the system comprises a fluid conduit extending between the environmental control unit and the coupling.

Preferably, the arm defines the fluid conduit.

Preferably, the fluid conduit is in fluid communication with an outlet of the environmental control unit such that conditioned air can be pumped from the environmental control unit to the coupling and into an aircraft fuselage. Preferably, the coupling comprises a receptacle defining a mouth adapted to be engaged against an aircraft fuselage, Preferably, the coupling comprises a deformable bellows.

Preferably, the environmental control system comprises a return duct in fluid communication with an inlet of the environmental control unit to facilitate closed loop conditioning of air within an aircraft fuselage.

Preferably, the return duct comprises a connector at an end of the duct opposite to an end communicating with the inlet of the environmental control unit.

Brief description of the drawings

The present invention will now be described with reference to the accompanying drawings, in which;

Figure 1 illustrates a perspective view of an aircraft environmental control system according to a first embodiment of the present invention;

Figure 2 illustrates a perspective view of an aircraft environmental control system according to a second embodiment of the present invention; and Figure 3 illustrates a perspective view of the aircraft environmental control system of Figure 2 configured for closed loop conditioning of air within an aircraft enclosure.

Detailed description of the drawings

Referring now to Figure 1 of the accompanying drawings there is illustrated an aircraft environmental control system, generally indicated as 10, which has particular application in the ground based conditioning of an aircraft's avionics compartment (not shown), or indeed any other desired enclosure of an aircraft such as a passenger compartment or the like, in particular which can be accessed through a fuselage of the aircraft, for example through one or more vents (not shown) located in the fuselage and which are provided to facilitate ventilation of said avionics compartment or other enclosure. It will however be appreciated from the following description of the invention that the environmental control system 10 of the invention may be modified to provide alternative functionality, with a particular emphasis on the transfer of fluid, in particular gas, to and/or from the aircraft, as will become apparent from the following description of the configuration and operation of the environmental control system 10. In the embodiment illustrated the system 10 comprises an arm or boom 12 which is constrained for rotation about a pivot axis 14 which defines an axis of rotation of a pair of wheels 16 by which the system 10 may be manually transported along the ground or other surface, such as for example the deck of an aircraft carrier or the like, in order to allow the system 10 to be positioned beneath an aircraft fuselage to perform the necessary conditioning, and as will be described hereinafter.

The system 10 further comprises a coupling 18, the configuration and operation of which will be described in greater detail, mounted on one side 20 of the arm 12 with respect to the pivot axis 14. The system 10 additionally comprises a counterweight 22 in the form of an environmental control unit such as a dehumidification unit 22 mounted on a second or opposed side 24 of the arm 12, again with respect to the pivot axis 14. In use the weight and/or positioning of the dehumidification unit 22 on the arm 12 is such that the moment of the dehumidification unit 22 about the pivot axis 14 is greater than the moment of the coupling 18 about the pivot axis 14. Thus the system 10 can be said to be weighted or biased in favour of the dehumidification unit 22 on the second side 24 of the arm 12, such that if no external influences or forces are brought to bear the system 10 will come to rest with the dehumidification unit 22 and/or second side 24 of the arm 12 in contact with the ground or other surface on which the system 10 is located, and the coupling 18 will therefore be suspended above the ground or other surface.

The coupling 18 comprises a receptacle 26 having an open mouth 28 circumscribing which is a deformable seal 30 which may be of any suitable form, for example a rubber or foamed plastic gasket or the like. A fluid transfer conduit 32 extends from an outlet (not shown) of the

dehumidification unit 22 to an underside of the receptacle 26, and thus provides a fluid transfer path between the dehumidification unit 22 and the interior space of the receptacle 26. Thus dehumidified or otherwise conditioned air may be pumped from the dehumidification unit 22 through the conduit 32 and into the receptacle 26. As mentioned above however, some other fluid or medium may be passed through the conduit 32 to and/or from the receptacle 26. In addition, one or more alternative characteristics of the air may be conditioned, for example the temperature of the air may be altered prior to being pumped into the aircraft enclosure.

In order to allow the environmental control system 10 to be manoeuvred into and out of position relative to an aircraft or other vehicle, the system 10 comprises a pair of handles 34 which are secured to the casing of the dehumidification unit 22. In addition a resilient bumper 36 is provided along an upper front edge of the dehumidification unit 22, in order to prevent damage to the fuselage of an aircraft or the like with which the environmental control system 10 is to be brought into register, in the event that the dehumidification unit 22 accidently contacts the fuselage.

In use an aircraft whose avionics or other compartment is to be dehumidified or conditioned in some way is parked at a suitable location at which the necessary maintenance work can be carried out. The access openings or vents in the fuselage which communicate with the avionics or other compartment are generally located on an underside of the fuselage for various reasons, and the environmental control system 10 is thus brought into position directly beneath these vents or openings. The system 10 is manoeuvred by using the handles 34 to lift the counterweight 22 and/or second side 24 of the arm 12 out of contact with the ground, and to bear the weight of the system 10 which may then be manually driven into position on the pair of wheels 16. The system 10 is in the correct position when the coupling 18, and in particular the mouth 28 of the receptacle 26, is located directly beneath the service vents communicating with the avionics compartment or other enclosure within the fuselage. In this regard the arm 12 is shaped and dimensioned such that when the system 10 is balanced on the pair of wheels 16 the mouth 28, and in particular the upper face of the seal 30, should be positioned at a height just beneath that portion of the underside of the fuselage in which the vents are located. The arm 12, in particular the first side 20 thereof, may therefore be adjustable in height and/or reach in order to suit various aircraft fuselage, and for example could be telescopic in length. At this point the environmental control unit 22 can be slowly lowered towards the ground, resulting in the coupling 18 being raised towards and into register with the underside of the fuselage. Once in contact with the fuselage the operator can release the handles 34 and the weight of the

dehumidification unit 22 acting about the pivot axis 14 will retain the coupling 18 against the underside of the fuselage. The deformable seal 30 will permit conformity with the fuselage in order to establish a suitably fluid tight seal between the mouth 28 and the fuselage. It is envisaged that the location of the pivot axis 14, relative to the boom 12, may be altered in order to vary the contact force exerted at the mouth 28 in order to ensure an appropriate seal is established with the fuselage or the like. In order to facilitate the location of the mouth 28 in the correct position and orientation against the fuselage, a guidance system (not shown) may be employed, for example one or more adhesive reference indicia or the like applied to the appropriate position on the fuselage or system 10.

At this point the dehumidification unit 22 can be actuated and will begin to pump dehumidified air through the conduit 32, out of the receptacle 26 and into the avionics or other enclosure via the vents or openings in the fuselage. The system 10 can be left in position without the presence of an operator while the dehumidification or other conditioning process takes place. The system 10 preferably incorporates an external weather proof power supply socket 38 to provide power to the system 10 and which can be left plugged in while the system 10 is located outdoors, potentially exposed to rain or the like. It will then be appreciated that should the environmental control system 10 need to be uncoupled from the aircraft, for example in the event that the aircraft is urgently required to be put into service, it is a simple matter of an operator taking the handles 34 and raising the dehumidification unit 22 upwardly in order to downwardly disengage the coupling 18 from the fuselage of the aircraft. The system 10 can then be wheeled out from beneath the fuselage and the aircraft is then ready to be used as necessary. No mechanical or other fastenings are required to be undone, thus significantly reducing the time and effort in disengaging the environmental control system 10 relative to conventional dehumidification apparatus.

Referring now to Figure 2 and 3 there is illustrated an alternative embodiment of air aircraft environmental control system, generally indicated as 110. In this alternative embodiment like components have been accorded like reference numerals and unless otherwise stated perform a like function. The system 110 comprises an arm 112 rotatable or pivotable about a pivot axis 114 defined by an axis rotation of a pair of wheels 116. The location at which the pair of wheels 116 are mounted to the arm 112 may be varied, such that the wheels 116 may be displaced towards one or other end of the arm 112 in order to vary the position of the pivot axis 114.

The system 110 further comprises a coupling 118 located on a first side 120 of the arm 112, and a counterweight in the form of a environmental control unit 122, for example dehumidification unit 122, on a second side 124 of the arm 112. The coupling 118 comprises an elongate receptacle 126 defining a mouth 128 circumscribed by a resiliently deformable seal 130. A screen or filter (not shown) may be provided in the bottom of the receptacle 126, or at any other location along the fluid transfer path from the environmental control unit 122, in order to filter out unwanted particulate matter which might otherwise prove harmful if allowed to enter the aircraft enclosure being conditioned by the system 110. The receptacle 126 is, in this embodiment, is provided in the form of a flexible metal bellows which is thus deformable in order to permit greater conformity with an aircraft fuselage or the like, which will often be formed of curved surfaces, and which will therefore enable a more complete seal to be achieved. It will of course be understood that the metal bellows could be replaced or augmented, for example with any other suitable functional alternative such as a plastic or rubber bellows, or other form. This type of arrangement could of course be employed with the other embodiments described and shown.

In the second embodiment the arm 112 defines a fluid transfer conduit 132 extending from the dehumidification unit 122. This design omits the requirement for the flexible conduit 32 of the first embodiment, thus increasing the robustness of the environmental control system 110. A gas strut 50, or any other functional equivalent, is coupled between the underside of the receptacle 126 and the arm 112 in order to stabilise the receptacle 126 when the system 110 is not coupled to an , .. aircraft.

The system 110 is engaged with the fuselage of an aircraft, and operates in the same manner, as . the first embodiment hereinbefore described, including an external weather proof power supply socket 38 to provide power to the system 110. A pair of handles 134 can be used to manoeuvre the system 110 into position beneath an aircraft fuselage to enable the coupling 118 to be engaged against the aircraft. However the elongate form of the receptacle 126 permits two or more vents to be captured beneath the receptacle 126 at the same time, thereby enabling two or more discrete enclosures or compartments within the fuselage to be dehumidified at the same time. In addition, by allowing the position of the wheels 116, and thus the pivot axis 114, to be varied the contact force exerted at the mouth 128 may be varied in order to ensure an appropriate seal is established with the fuselage or the like.

The aircraft environmental control system 110 additionally comprises an auxiliary port 50 located, in the embodiment illustrated, on an upper face of the arm 112, and thus providing access to the fluid transfer conduit 132 defined by the arm 112. It is thus possible to open the auxiliary port 50, connect one end of a suitable section of ducting (not shown) to the port 50, and to connect the other end of the ducting (not shown) to an aircraft vent or the like, preferably using a suitable coupling (not shown) to provide an interface between the end of the ducting and the opening or vent in the aircraft fuselage. The auxiliary port 50 thus provides an alternative or additional outlet from which conditioned air from the environmental control unit 122 may be pumped into the aircraft.

Turning then to Figure 3 there is illustrated the system 110 of Figure 2 but configured, as hereinafter described, to permit the closed loop conditioning of air within an aircraft enclosure such as the cockpit, a dedicated avionics compartment, or any other desired space.

The system 110 comprises a return port 52 on the environmental control unit 122 to which a return duct 54 may be secured is fluid tight fashion at one end of the duct 54, the other end of the duct 54 being provided with a connector 56 which is connectable with an outlet or exhaust port/vent (not shown) of an aircraft enclosure to be environmentally conditioned. The connector 56 may be of any suitable form, and in the embodiment illustrated is configured for connection with a window (not shown) of an aircraft where a cockpit of the aircraft is to be dehumidified. It should however be understood that the connector 56 and/or duct 54 may have any other configuration for connection to alternative openings or vents in an aircraft.

Thus in operation the coupling 118 is engaged, as hereinbefore described, about a vent (not shown) in a fuselage of the aircraft, which is in fluid communication with the cockpit enclosure or other enclosure to be conditioned. The connector 56 is also connected to an opening in an otherwise sealed window of the cockpit. The dehumidification unit 122 can then be actuated, such that air is sucked out of the cockpit, through the return duct 54, and passed through the dehumidification unit 122. The air is then conditioned by the unit 122 before being pumped back into the cockpit or other enclosure via the coupling 118. It will therefore be appreciated that the system 110 is adapted to perform closed loop conditioning of the air. Depending on the external environmental conditions, this may be preferable to the open loop conditioning described with reference to Figure 1 and 2, in particular when the relative humidity (Rh) of the external environment is high. Closed loop conditioning in such environments will significantly reduce the workload on the dehumidification unit 122. It also allows the Rh values of the particular aircraft enclosure to be measured and monitored.

The system 110, in particular the dehumidification unit 122, may be provided with one or more sensors (not shown), for example to permit the above mentioned Rh value to be monitored. Thus for example the dehumidification unit 122 may be provided with a humidity sensor in operative association with the outlet and/or coupling 118, and/or in operative association with the inlet of the unit 222. The output from these sensors may then be used by, for example, control systems or algorithms of the unit 122. The system 110 may also employ a smoke or heat sensor in order to monitor for the presence of smoke and/or fire within the dehumidification unit 122. Finally, the system 110 may be provided with a guidance or alignment system 58, for example one or more visual reference guides 58 which, when correctly aligned with one or more positions or features on the fuselage of the aircraft, ensure that the system 110 is correctly aligned with the aircraft in order to allow the proper operation of the system 10. It will of course be appreciated that the system 10, 110 of the present invention provides a simple yet highly effective and efficient means of engaging a environmental control unit or other services with the fuselage of an aircraft, while permitting the immediate disengagement of such a system 10, 110 when required.