WO1993009028A1

WO1993009028A1 - Apparatus for and a method of de-icing

Info

Publication number: WO1993009028A1
Application number: PCT/GB1992/001983
Authority: WO
Inventors: Francis John Baker; Alan John Melrose
Original assignee: MANCHESTER AIRPORT PLC; Norweb PLC
Current assignee: MANCHESTER AIRPORT PLC; Norweb PLC
Priority date: 1991-11-01
Filing date: 1992-10-29
Publication date: 1993-05-13
Anticipated expiration: 1994-05-01
Also published as: GB2276601A; AU2792892A; GB9408478D0; GB9123179D0

Abstract

Apparatus for de-icing an aircraft comprises infrared radiation emitters (6, 7, 8) connected to members (3, 4 and 5) of a structure through which the aircraft passes. Detectors (10) detect the position of the aircraft and a thermal imaging system comprising cameras (11) provides an assessment of de-icing quality. In an alternative emitters may be mounted on a self-propelled vehicle.

Description

APPARATUS FOR AND A METHOD OF DE-ICING

The present invention relates to apparatus for and a method of de-icing. The apparatus and method have particular, but not exclusive, application to aircraft and airfield surfaces.

The removal of ice, in its various forms, from aircraf and airfield surfaces is the subject of strict legislative and procedural directives throughout the world. The presence of ice on aircraft control surfaces, in particular, before and during take-off is not allowed and can result in major international disasters and major loss of life. The current normal method of ice removal from both aircraft and airfield surfaces is by the use of environmentally harmful and costly chemicals. The chemicals are comprised principally of ethylene and propylene glycols, urea and acetate based de-icing agents. Alternative methods of de-icing have principally been applied to ground surfaces and used convective heat or visible light from 300-700 nanometers as described in US Patent No. 3,471,682 and UK Patent No. 1,431,726 respectively. There is no known method of ensuring that an aeroplane or airfield surface is sufficiently de-iced other than by using the experience and judgement of the person responsible to declare a ground surface safe or an aeroplane fit for take-off. The aforesaid lack of definition as to the quality of ice removal can result in the over-use of harmful chemicals in order to allow an acceptable safety margin, or worse, in an error of judgement.

According to one aspect of the present invention, there is provided apparatus for de-icing comprising at least one infra-red radiation emitter arranged to direct infra-red radiation at a surface to be de-iced.

According to another aspect of the present invention there is provided a method of de-icing including the step of directing infra-red radiation at the surface to be de-iced.

In a preferred embodiment of the invention for an aircraft, a plurality of infra-red radiation emitters are mounted on one or more supports. The support(s) may simply comprise towers disposed on opposite sides respectively of the path the aircraft is to follow to its take off point on the runway. The mounting of each emitter on its support may be motorised. This enables the direction, position and focus of the emitter to be adjusted as desired advantageously under computer control running on the software specially written having regard to, inter alia, aircraft type, and ambient conditions. The supports may also carry aircraft detectors and thermal imaging systems. Detectors enable the system to detect the presence of an aircraft and switch on automatically in response. Thermal imaging enables the thermal state of the aircraft to be checked and, if desired, a record to be produced of that state. Emitters may also be disposed in the ground and protected from impact damage by motorised covers grillage and/or careful location and/or designed to withstand conceivable impact using heavy duty impact resistant materials or retractable narrow emitters. Filters on emitters may be removable so that the system may be used for illumination when necessary.

Instead of static structures through which an aircraft moves, the aircraft may be stationary and the emitters moved on a vehicle which may be stationary or moved with respect to the aircraft. Alternatively, a combination of vehicle and aircraft movements may be employed. For example, the vehicle may support emitters on fixed or movable members which may be moved to positions both above and below the wing, for example. The aircraft may then be moved relative to the vehicle when .in this position. Each side of the aircraft may be de-iced sequentially or both sides may be de-iced simultaneously using two vehicles on opposite sides respectively of the aircraft. The movable members on the vehicle may be hydraulically or pneumatically operated. The vehicle may carry its own generator or it may be plugged into a local power supply. Emitters are advantageously not more than ten metres and preferably less than five metres away from the surface to be de-iced. The wavelength of the infra-red radiation employed is preferably in the range 0.7 microns to 0.5 millimetres and advantageously in the range 0.7 to 2 microns.

The infra-red treatment may be used alone to melt ice, dissipate the water and dry the surface de-iced or it may be used for any or all of the above purposes in conjunction with a hot water or hot air pre-treatment. Although intended principally for aircraft de-icing the method and apparatus may be used for taxiways; railways and runways or in other areas as appropriate.

The thermal imaging system or some other temperature measuring device may be used to control the focus, intensity number or position of the emitters automatically. Thus, optimising the de-icing process and/or improving system energy efficiency.

That the invention may be used successfully is surprising as evidenced by the comments on infra-red radiation in US Patent No. 3,964,183 which considers this form of radiation but dismisses it as unworkable.

In order that the invention may be more clearly understood, one embodiment thereof will now be described by way of example with reference to the accompanying drawings, in which:-

Figure 1 shows diagrammatically a plan view of one embodiment of apparatus according to the invention,

Figure 2 shows diagrammatically an end elevational view of the arrangement of Figure 1,

Figure 3 shows diagrammatically a plan view of a second embodiment of apparatus according to the invention,

Figure 4 shows diagrammatically an end elevational view of the arrangement of Figure 3.

Figure 5 shows a diagrammatic end elevational view of a third, mobile, embodiment of the apparatus of the invention to that of figures 1 and 2.

Referring to Figures 1 and 2, the apparatus comprising a hangar like structure 1 spanning a taxiway on a convenient location on the airfield. This would normally be at a position reasonably adjacent the main runway so as to minimize the distance the aircraft has to travel between de-icing and take off. The structure comprises five supports 2, made, for example, of steel. Each support 2 comprises two uprights 3, two inclined members 4 and one central horizontal member 5. Two infra-red radiation emitters 6 are connected to each upright 3, one 7 to each inclined member 4 and three 8 to each central horizontal member 5. An aircraft 9 is shown within the structure. Detectors 10 for detecting the presence/position of an aircraft 9 within the structure are disposed on the uprights 3.

A thermal imaging system is also mounted on the structure 1. This system comprises several cameras 11 positioned as shown to photograph the aircraft 9 and provide an instant assessment of the quality of de-icing and, if necessary, a hard copy thereof prior to take-off. This could be simultaneously generated for the aeroplane's flight recorder (black box) the pilot in his cockpit, the Ground Movement Control and Air Traffic Control and the system generator. This would allow the positive assessment of fitness to fly. Power consumption would be metered and invoices issued as appropriate all under control of the computer system if desired.

Referring to Figures 3 and 4, an alternative apparatus is shown. This is similar to the arrangement of Figure 1 and 2 except that the infra emitters are all mounted on upright supports laterally of the aircraft, taxiway. No emitters are mounted on supports directly above the aircraf taxiway. Parts equivalent to the parts of the embodiment of Figures 1 and 2 bear the same reference numerals.

The two embodiments of Figures 1 to 4 are purpose built. However, if desired emitters could be mounted on existing structures provided they are suitably located. Emitters could also be disposed in the floor. When so disposed, they would advantageously be protected from impact damage by motorised covers, grillage and/or selective location.

Referring to Figure 5, a mobile de-icing apparatus is shown. This comprises a self propelled vehicle 20. A lower platform 21 supporting two infra-red emitters 22 and an upper hydraulic arm 23 supporting four infra emitters 24 on a folding mounting 25 extend from the vehicle. The vehicle may carry its own generator, which may be diesel or liquid gas fuelled, or it may be plugged into a suitable power supply. This arrangement enables aircraft to be de-iced as a batch operation. With the arrangement shown, the aircraft is moved relative to the apparatus once the apparatus is in position relative to the apparatus. The process may then be repeated for the other side of the aircraft or, alternatively two vehicles may be positioned simultaneously on opposite sides respectively of the aircraft. In a modified version, the vehicle(s) may be moved relative to the aircraft with the aircraft stationary. The vehicle may also carry aircraft detectors and a thermal imaging system as already described.

The number and spacing of the supports, the emitters, and the detectors may be varied as desired. The connection of each emitter and detector is adjustable so that its direction may be adjusted as desired. The distance of each emitter from the aircraft to be de-iced may also be varied as desired. It is expected that this spacing will usually not exceed ten metres from the aircraft surface and will usually be less than five but the precise spacing will be chosen in dependence upon the number of emitters and their direction in order to ensure sufficient infra-red radiation levels at the surface itself. Each emitter may be focused for optimum results and its mounting motorised to provide for powered adjustment. The focus, angle of application, power level and position of all the emitters would be computer controlled running on specialist software written having regard to the aircraft type to be de-iced and taking into account the ambient conditions. It is expected that the wavelength of the infra-red radiation would be in the range 0.7 microns to 0.5 millimetres and preferably in the range of 0.7 to 2 microns.

In use of the above described apparatus the infra-red heat will be produced-at varying optimum distances from the surfaces to be de-iced. The infra-red energy will pass through the surrounding air and moisture without undue loss of power and immediately start to warm the snow, ice, water and surfaces it impinges upon. The affected snow and ice will progressively melt, run off and evaporate from the surface leaving them dry. Alternatively, the ice could be initially melted by hot water spray or removed by air blast, the process being finished by infra-red heat. Surfaces could then be further warmed to an acceptable temperature between 0°C and 150°C building up a thermal store of heat if necessary. The warmed, dry surfaces will allow sufficient time for the aircraft to taxi to take-off position, be checked using thermal imaging or infra-red thermometer readings and subsequent take-off. The wavelength of the emitters could be individually tuned or variably tuned to the optimum wavelength for each stage of the process, that is, heating ice, heating water, heating polished/painted alloy.

Motorised universal mounts may be developed to allow the emitters to move to focus on the specially required surfaces for each aircraft type and to follow the aircraft should it be de-iced whilst moving.

The emitters and associated control gear are designed to be weatherproof. A preferred emitter is a quartz halogen short wave infra-red heat type using between 3 and 15 Kw each. Generating infra-red heat, and light if required, the emitters will have an effective range of up to 200 feet. The correct position/focus/intensity of emitters may be determined by the simple insertion of a digital magnetic card/key/button selection which allows a single untrained operator to select a complicated predetermined emitter arrangement.

The philosophy for aircraft coverage will be - to have an automatic system of emitter movements managed from a computer with a data base of known aircraft types and weather data coupled with a variable menu, selectable parameters to be input manually or via computerised communications from the CAA or aircraft pilot to ensure the full and safe de-icing of the aircraft. Filters on the emitters could be removed to produce illumination thus saving on lighting costs.

As compared with presently used chemical methods, the above described method and apparatus have substantial environmental advantages. Eliminating or reducing the use of chemicals leads to savings on chemical effluent processing, savings on chemical storage, savings on chemical handing and possible savings in terms of the corrosive effect of glycol on ground and aircraft (paintwork?) . Further more general advantages may be secured as follows. Licence fees for chemical discharge may be reduced or eliminated. Automatic apparatus operation can lead to manpower saving. Less frequent de-icing applications may be required leading in turn to energy savings. In the general area of airport operations, faster turnround of aircraft due to effectiveness of the infra-red method; shorter queuing time for outbound aircraft; less schedule disruption due to missing of aircraft control windows and less danger of litigation from chemical discharge may be achieved. In the general field of airline operations, load factor can be increased due to dry skin on aircraft after infra-red application; localized application can be achieved where necessary; whole aircraft de-icing can be achieved where required; and less schedule disruption yielding greater customer service levels can be secured. Also, the provision of de-icing certification adds to safety documentation systems.

It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the scope of the invention.

Claims

1. Apparatus for de-icing comprising at least one infra-red radiation emitter (6,7,8) arranged to direct infra-red radiation at a surface to be de-iced.

2. Apparatus as claimed in claim 1, in which a plurality of infra-red radiation emitters (6,7,8) are mounted on one or more supports (3,4,5) .

3. Apparatus as claimed in claim 2, in which the mounting of each emitter is motorised.

4. Apparatus as claimed in claim 3, in which each motorised mounting is computer controlled.

5. Apparatus as claimed in any preceding claim, comprising a thermal imaging system (11) , operative to produce a thermal image of a de-iced body.

6. Apparatus as claimed in any preceding claim comprising detectors CIO) for detecting the presence of a body to be de-iced.

7. Apparatus as claimed in any preceding claim, mounted on a vehicle (20) movable relative to a body to be de-iced. 8. Apparatus as claimed in any preceding claim, in which the or each emitter (6,7,

8) is disposed less than ten metres from the surface to be de-iced.

9. Apparatus as claimed in any preceding claim, in which the or each emitter (6,7,8) is disposed less than five metres from the surface to be de-iced.

10. Apparatus as claimed in any preceding claim, in which the or each emitter (6,7,8) is operative to emit radiation having a wavelength in the range 0.7 microns to 0.5 millimetres.

11. Apparatus as claimed in any of claims 1 to 9, in which the or each emitter (6,7,8) is operative to emit radiation having a wavelength in the range 0.7 microns to 2 microns.

12. Apparatus as claimed in any preceding claim, in which means are provided for a hot water pretreatment.

13. Apparatus as claimed in any preceding claim, in which means are provided for a hot air pre-treatment.

14. A method of de-icing including the step of directing infra-red radiation at the surface to be de-iced.

15. A method of de-icing an aircraft in which the aircraft is moved through the infra-red radiation.

16. A method of de-icing an aircraft, in which the radiation is directed over the aircraft.