The present invention relates to a device and a method for recovering de-icing and/or anti-icing liquids from airport apron/deicing platform - surfaces.

Background of the invention/Background Art

In connection with the removal of ice or from or ice prevention on surfaces of airplanes, a deicing or anti icing liquid is sprayed on the airplane Traditionally, removal of ice from airplanes is done in two main steps, the first step being a de-icing step, wherein ice and snow deposited on the surface of the airplane is removed, the second step being an anti-icing step, wherein the surface of the airplane is covered with a protective liquid, which precludes formation of new ice on the surface of the airplane. The de-icing and the anti-icing liquids are typically a mixture of glycol, water and various further compounds, called additives.

In the de-icing step it is known to use a pre-heated liquid, which is a mixture of water and a so called Type 1 de-icing liquid. The Type 1 de-icing liquid has a low viscosity and it is primarily the thermal energy of the liquid, which causes the melting and removal of the ice (and possible snow deposits) from the airplane.

The anti-icing step is performed by applying a protective layer of anti-icing liquid on the surface of an airplane in order to prevent the formation of a new layer of ice on the sur- face of the airplane before it has left the apron/deicing platform.

Excess deicing and/or anti-icing liquid drains from the airplane, and will remain on the ground surface at the de-icing/anti-icing location, when the airplane has finished treatment.

Due to environmental considerations, a controlled emission is desired in many airports. Further, it may be desirable to collect excess de/anti-icing liquid for recycling purposes.

Today, typically the collection of excess deicing and anti-icing liquid from runway, apron or specialized deicing platform surfaces is performed in airports by utilizing trucks equipped with heavy-duty suction devices. By the aid of vacuum, deicing/anti- icing liquid is sucked up through a nozzle and into a tank on the truck. The vacuum is build up by use of a large blower In order to provide a sufficient vacuum and air speed, considerable power is needed, typically in the order of 250 to 350 kW. Further, appli- cation of a suitable vacuum requires a very precise control of the distance between the apron/deicing platform surface and the nozzle. This may be very difficult, especially if snow and ice mixed with liquid is present on the apron/deicing platform surface. An example of such trucks is disclosed in US 2010/0147331 A1. With an increased focus on energy consummation reduction, it would be desirable to provide a more energy and cost efficient solution for removing and recollecting excess deicing/anti-icing liquids from apron/deicing platform surfaces in airports or other places where deicing/anti icing could take place. However, when the deicing and/or anti icing process is needed, snow and ice further forms on the apron/deicing platform. Therefore, when the de-icing/anti-icing liquid is collected, snow, slush and/or lumps of ice, as well as debris/stones/gravel is introduced into and mixed with the de-icing/anti-icing liquid. It is therefore desirable to avoid or reduce mixing and/or to provide means for separating the solid compounds (snow, ice, debris, gravel) from the liquid factions.

WO 95/14823 A1 discloses a truck with a horizontal axis, cylindrical brush, which sweeps water, de-icing liquid, ice, snow, slush, debris, gravel, etc. on to a transport elevator. The transport elevator is heated to melt ice, snow, and slush, and transport the swept components up to a first tank in the truck, where it is heated in order to melt any remaining ice, snow, and slush. From the first tank, the melted compounds may be transferred to a second container for storage via suitable piping. The disclosed truck is a cumbersome, intricate construction, and uses a large amount of energy and space for collecting and storing the collected compounds. Further the mixing of huge amounts of material creates logistical problems relating to subsequent storage, transport and treatment of the collected substances.

Disclosure of the invention

On this background, it is an object of the present invention to provide a simpler more energy and cost efficient method, system and unit for recovering deicing/anti icing liquids from airport apron/deicing platform surfaces. Further, it is an object to provide a system and unit which constitute an alternative to the traditional glycol suction vehicles. It is a further object of the present invention to provide a de- and/or anti-icing liquid recovering method, system, and unit, by which many of the logistical problems mentioned above are alleviated.

In a first aspect of the invention this object is achieved by providing a de-icing and/or anti-icing liquid recovery system for recovering de-icing and/or anti-icing liquids from airport apron and/or deicing platform surfaces, the system comprising:

- a deicing-liquid recovery unit;

- a pump; and

- a collection tank,

where the deicing/anti-icing liquid recovery unit comprises

- a rotatable brush;

- a baffle; sand

- a sorting tray fluidly connectable to said collection tank via pump,

wherein the rotatable cylindrical brush is arranged to sweep a apron/deicing platform surface such that materials on the apron/deicing platform surface is forced over the baffle and into the sorting tray through an inlet opening formed in the sorting tray, wherein said sorting tray comprises means for retaining solid phase materials from said swept-up material in a first portion of said sorting tray and letting liquids from said swept- up material pass through and into a second portion of said sorting tray;

wherein liquids collected in second portion of said the sorting tray can be pumped to the collection tank via said pump; and

wherein said sorting tray further comprises an exit port for removal of solid phase materials. The "means for retaining solid phase materials from said swept-up material in a first portion of said sorting tray and letting liquids from said swept-up material pass through and into a second portion of said sorting tray" could also be called "means for sorting" or "sorting means". The sorting tray may be formed as a part of a housing of said deicing/anti-icing liquid recovery unit or as a separate part, inserted in or insertible into a housing of the deicing/anti-icing liquid recovery unit. The inlet opening and the exit port may be formed in the sorting tray and/or in the housing.

The materials to be swept from the airport apron/deicing platform surface are deicing and/or anti-icing liquid, water, snow, ice and slush, as well as gravel/debris/dirt. This material has two major constituents, a liquid constituent comprising deicing and/or anti- icing liquid and/or water, and a "dry" or solid-phase constituent, comprising snow, ice and gravel/debris/dirt.

By such a system the dry/solid-phase materials can be expelled and the liquid materi- als/constituents can be collected. Thus, a more compact recovery system may be obtained. Further the recovery system use far less energy than the prior art suction vehicles or sweeping vehicles. When the "dry" materials have been expelled back on to the apron/deicing platform surface they may be removed or simply brushed to the side by conventional means. The system secures that deicing and/or anti-icing liquid has a higher concentration (with respect to water) than in the prior art. This makes it easier and more cost efficient to separate and recycle/dispose of the liquid afterward.

The 'means for retaining solid phase materials from said swept-up material in a first portion of said sorting tray and letting liquids from said swept-up material pass through and into a second portion of said sorting tray' may be a filter/grid/mesh, and may be configured such that the solid phase materials contained in the swept up materials may be retained on one side of the means enough for liquids contained in the swept-up material to pass there through. The exit port for removal of solid phase materials may in a simple embodiment be an access door allowing a user to gain access to the sorting tray and manually shovel or brush out the solid phase materials retained on the 'means for retaining solid phase materials from said swept-up material in a first portion of said sorting tray and letting liquids from said swept-up material pass through and into a second portion of said sort- ing tray'. In another simple embodiment, where the 'means for retaining solid phase materials from said swept-up material in a first portion of said sorting tray and letting liquids from said swept-up material pass through and into a second portion of said sorting tray' is a filter/grid/mesh, the filter/grid/mesh may be removed from the sorting tray through the exit port, and the solid phase materials may thus be removed from the sorting tray, after which the filter/grid/mesh may be reinserted into the deicing/anti-icing liq- uid recovery unit.

In an embodiment the rotatable brush is a horizontal axis cylindrical brush having a horizontal rotational axis A. In a further embodiment, the deicing-liquid recovery unit further comprises an expulsion mechanism for expelling solid phase materials swept into said sorting tray. In a further embodiment hereof, the solid-phase materials are expelled through an exit port formed in a sidewall of said deicing-liquid recovery unit. This allows for the deicing-liquid recovery unit to be made very compact and secures that wheels of the deicing/anti-icing liquid recovery unit or a vehicle to which it is mounted, do not compact the expelled materials when moving forward.

In a further embodiment the expulsion mechanism is an auger/screw conveyer. Thereby, an efficient expulsion mechanism is provided which at the same time transports the dry materials in one direction (which is preferably towards the exit port) and at the same time compressing the materials to press out the liquid constituents. This also increases the efficiency of the recovery of deicing/anti-icing liquid. The auger may be arranged along-side a mesh keeping back the "dry'Vsoli-phase materials and allowing the liquids to pass. A rotational axis B of the auger may be arranged parallel to a rotational axis A of a rotational horizontal axis cylindrical brush. Thereby a compact deicing/anti-icing liquid recovery unit may be obtained.

In yet an embodiment, an external bottom side of the sorting tray is configured to be located 3-100 cm, such as 5-50 cm, such as 5-20 cm, preferably 5-15 cm above ground, i.e. the airport apron/deicing platform surface during use of the deicing/anti-icing liquid recovery unit and system. This may be provided by suitable dimensioning of a frame, wheels and/or mounting means of the deicing/anti-icing liquid recovery unit. Thereby a low position of the sorting tray is provided. Consequently, a more compact deicing/anti- icing liquid recovery unit may be obtained. Also, the low location of the sorting tray allows to keep the sorting tray away from heat sources of the machinery, to avoid heating of the swept up materials at least until they have been sorted. Further, the low location of the sorting tray secures that the brush can more easily lift the liquid/wet and dry/solid phase material into the sorting tray, and thereby avoid additional transportation of the liquid/wet and dry/solid material. Thereby, a more compact unit and system may be provided, which is further more easy to maintain or repair, and which uses less energy.

In yet an embodiment, an upper edge 12" of the baffle 12 is located at a height above the external bottom of the sorting tray of 3-60 cm, such as 5-20 cm, and preferably 5-20 cm. Thereby a compact deicing/anti-icing liquid recovery unit may be obtained. In a yet further embodiment, the system may further comprise

- two or more collection tanks, and

- a control valve may be associated with each tank and arranged to control the fluid connection to each tank from the sorting tray. This allows to separation of liquids having different compositions. An example could be glycol concentration, where factions having a low glycol concentration could be directed into one collection tank and factions having a high concentration of glycol could be directed into another collection tank. This may simply be done by an operator of the system manipulating the valves based on e.g. a visual inspection of where on the apron/de- icing platform spilt high and low glycol concentration are situated.

However, in a further embodiment the system may alternatively or additionally comprise

- a sensor configured for measuring a composition of liquids passing through a fluid connection from the sorting tray to the collection tanks,

- a control system configured to receive input from the sensor and to provide a control signal to each of the control valves, and

- the control system may further be configured for distributing liquid to the collection tanks based on a measured composition of the liquid and a predetermined set of thresholds.

Thereby, the system allows automatically separating the collected liquid into factions, dependent on their composition. By measuring the glycol concentration in the collected liquid, the liquid may via suitable control valves be directed to the collection tank having a corresponding glycol concentration, thereby securing an optimized recycling of the glycol. The sensor may measure the selected measuring parameter, such as glycol concentration, continuously or in predetermined time intervals. In a second aspect of the invention, the object may be obtained by a deicing-liquid recovery unit for a system according to any one of the embodiments described above. The unit may be mounted on a vehicle such as a tractor or truck. The vehicle may provide power for operating the unit, and may further carry the one or more collection tanks, and the pump of the system as described above.

Thus, in an embodiment of the deicing-liquid recovery unit, it further comprises coupling means for attaching the deicing-liquid recovery unit to a vehicle, and means for coupling the sorting tray to a pump and collection tank(s) arranged on the vehicle.

In a third aspect, the objects of the invention are obtained by a method for recovering de-icing and/or anti-icing liquids from airport apron/deicing platform surfaces, said method comprising:

- moving a rotational brush over an airport apron/deicing platform surface,

- sweeping materials comprising one or more of deicing and/or anti-icing liquid; water; ice; snow; and gravel from said airport apron/deicing platform surfaces and into a sorting tray over a baffle by rotating said rotatable brush,

- separating liquids from solid-phase materials contained in said swept-up materials in said sorting tray,

- pumping said liquids from said sorting tray and into a collection tank, and

- expelling said solid-phase materials from the sorting tray. In an embodiment said solid-phase materials are expelled from the sorting tray. In a further embodiment, preferably, the solid-phase materials are expelled on to the airport apron/deicing platform surfaces.

In an embodiment, the swept-up materials are compressed to squeeze liquids from the solid-phase material content of the swept-up materials. This may in an embodiment be achieved by an auger/screw conveyor. The auger may be arranged along-side a mesh keeping back the "dry'Vsoli-phase materials and allowing the liquids to pass.

In an embodiment, the method further comprises selectively distributing portions of the liquid pumped from the sorting tray into two or more collection tanks. Thereby, separation of portions of the liquid materials having different compositions is allowed. An example of different compositions could be glycol concentration. Thus, factions of the liquid material having a low glycol concentration could be directed into one collection tank and factions having a high concentration of glycol could be directed into another collection tank. This may simply be done by an operator of the system manipulating valves associated with each collection tank, based on e.g. a visual inspection of where on the apron/deicing platform spilt high and low glycol concentration are situated.

However, in a further embodiment of the method the selective distribution of the liquid into the two or more collection tanks comprises

- measuring a composition of the liquid pumped from the sorting tray; and

- selectively distributing the liquid into the two or more collection tanks based on the measured composition and predetermined thresholds for a selected content of a component of the liquid.

Thereby, the method allows automatically separating the collected liquid into factions, dependent on their composition, e.g. the glycol concentration. By measuring the glycol concentration in the collected liquid, the liquid may via suitable control valves be directed to the collection tank having a corresponding glycol concentration, thereby securing an optimized recycling of the glycol.

In an embodiment thereof a glycol concentration is measured and the liquid is distributed into one of the two or more collection tanks based on a predetermined glycol concentration threshold.

The measurement of the composition may be a continuous measurement.

In a fourth aspect of the invention, the method according to any one of the embodiments described above is applied in a system according to any one of the embodiments de- scribed further above.

In a fifth aspect of the invention, a de-icing and/or anti-icing liquid recovery system for recovering de-icing and/or anti-icing liquids from airport apron/deicing platform surfaces (90) according to any one of the embodiments described above is used in a method a method for recovering de-icing and/or anti-icing liquids from airport apron/deicing platform surfaces according to any one of the embodiments of the method described above. Further objects, features, advantages and properties of the de-icing and/or anti-icing liquid recovery system and unit, as well as the method according to the invention will become apparent from the detailed description.

Brief description of the drawings

In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiments shown in the drawings, in which:

Fig. 1 is a diagrammatic depiction of a deicing liquid recovering system and unit according to an embodiment of the present invention;

Fig. 2 is a diagrammatic depiction of a deicing liquid recovering unit according to a second embodiment of the invention;

Fig. 3 is a diagrammatic depiction of a deicing liquid recovering unit according to a third embodiment of the invention; and

Fig. 4, in a perspective view, shows a deicing liquid recovering unit according to a further embodiment of the invention. Detailed description of the invention

In the following detailed description of the method, system and unit for recovering de- icing liquid according to the invention will be described by the preferred embodiments.

Throughout, the detailed part of this description, for the sake of simplicity, reference will be made to deicing liquid. It will however be understood that both deicing and anti-icing fluid as well as other liquids will be and is intended to be recovered by the method, system and unit according to the invention.

Fig. 1 shows a first exemplary embodiment of a system 1 and a unit 10 for recovering deicing liquid. The system 1 comprises unit 10 for recovering deicing liquid, a pump 20 and a first collection tank 30. The unit 10 comprises a rotatable brush 11 , such as a rotatable horizontal axis generally cylindrical brush, a baffle 12, and a sorting tray 13. The sorting tray 13 has an outlet 14 arranged at a lower portion thereof. The unit 10 may comprise a housing 18 encapsulating the rotatable brush 1 1 , the baffle 12, and the sort- ing tray 13. In an embodiment, the sorting tray 13 is detachably connected to the housing 18 forming a detachable bottom portion thereof. In other embodiments, the sorting tray forms a fixed bottom part of the housing 18. In yet other embodiments the sorting tray 13 may be formed as closed structure, thereby defining a housing 18. Such an embodiment is illustrated in Fig. 4. The sorting tray 13 is connectable to the pump 20 via piping 21. Thereby piping 21 fluidly connects the outlet 14 of the sorting tray and an inlet of the pump 20. Further, the pump 20 is fluidly connected to the first collection tank 30 via piping 22.

The unit 10 for recovering deicing and/or ant-icing liquid may be mounted on or attached to a vehicle, such as truck or a tractor (not shown). As shown in Fig. 4, the unit 10 may further comprises a frame 60 with wheels 61 , 62. Thereby, the unit 10 may be connected to a vehicle, such as a truck or a tractor, via suitable connection means 63. In the embodiment shown in Fig. 4, the unit 10 is configured for mounting in front of the vehicle. However, in other embodiments, the unit may alternatively be configured to trail the ve- hide.

Preferably, the first collection tank 30 may be arranged on or trailing the vehicle. In alternative embodiments the first collection tank 30 may be formed on the unit 10. Preferably, the pump 20 is formed on the vehicle, or on a trailer carrying the first collection tank 30. Alternatively, the pump 20 may be formed on the unit 10. The piping 21 , 22 is preferably at least partially formed as a flexible tubing, especially if the unit 10 and the tank are separated.

Further shown in Fig. 1 is a surface 90, such as an airport apron/deicing platform sur- face. On the surface 90 a material 91 is deposited. The material 91 deposited on the surface 90 is a mixture comprising one or more of surplus deicing/anti icing liquid, ice, water, snow, slush, debris, gravel. The surplus deicing/anti icing liquid has drained of an airplane, which has been treated with deicing liquid or anti-icing liquid or both. When the surplus deicing/anti icing liquid drains of the airplane, it mixes with ice, snow, slush, water, and/or debris/gravel already on the surface 90.

In order to remove the surplus deicing/anti icing liquid it is necessary to remove first all the material 91 on the surface 90 including the drained-of deicing and anti-icing liquid. This is done by moving the system 1 , or at least the unit 10, over the surface 90, while rotating the rotatable brush 11. This situation is illustrated in Fig.1 by the arrow 50, indicating the movement direction of the unit 10 relative to the surface 90. In Fig. 1 , the arrow 51 indicates a rotation direction of the rotatable brush 11. As may be appreciated from Fig. 1 , the rotatable brush 1 1 , the baffle 12, and the sorting tray 13 are arranged relative to each other such that, when the unit 10 passes over a surface 90, such as an airport apron or deicing platform surface, materials 91 deposited on the surface 90 are swept over the baffle 12 and into the sorting tray 13 by rotating the rotatable brush 11. The rotatable brush 11 brushes the materials through an inlet opening 17, which in the embodiment shown in Figs. 1-3 is provided through a housing 18 in which the sorting tray 13 is arranged. In other embodiments, a similar inlet opening 17 may be provided into the sorting tray 13 in embodiments, where the sorting tray 13 is formed as a closed structure, and thus defines a housing 18 by itself, as e.g. illustrated in Fig. 4.

The rotatable brush 11 rotates about an axis A, which in this embodiment is perpendicular to the movement direction 50 of the unit 10 relative to the surface 90, and parallel to the surface 90, i.e. horizontal. The baffle 12 preferably comprises an inclined surface having a lower edge 12' and an upper edge 12".

In Fig. 1 , the material 91 passing over the inclined surface of the baffle 12 is indicated with the reference number 92. The material swept into the sorting tray 13 is - as implied above - a mixture of liquid and solid substances. By liquids are meant water, fluid de- icing or anti-icing liquid, and to a certain degree slush. By 'dry' or 'solid phase' substances is meant snow and ice (solid-phase water), and debris/gravel.

As indicated in Fig. 1 , the dry/solid phase substances 93 will accumulate in the upper portion of the sorting tray 13, while the fluid substances 94 will drain to the bottom 13' of the sorting tray 13.

There may be a horizontal grid/mesh/filter 15 or the like (not shown) separating the sorting tray 13 in two parts a bottom or lower portion and an upper or top portion. In Figs. 1 and 3, the grid/mesh/filter 15 may simply be resting on top of the sorting tray 13. Thereby, the upper or top portion may be defined above the sorting tray as such, but inside the housing 18 of the unit 10. In the embodiment shown in Figs. 1-3, the lower portion is defined between the mesh/grid/filter 15 and the bottom 13' of the sorting tray 13. The liquids draining to the bottom 13" of the sorting tray are removed via the outlet 14 by use of the pump 20. The pump 20 pumps the liquids into the first collection tank 30.

In Fig. 1 and 3 the grid/mesh/filter 15 arranged in the horizontal plane. It is clear that the piled up materials indicated with reference number 93 in Figs. 1-3 contains both liquid /fluid substances/materials and dry/solid phase substances/materials, but the piled up materials will begin to drain off quickly, either passively via the filter, or actively in combination with mechanisms to squeeze or press the materials 93. Therefore for the sake of simplicity, the materials indicated by reference number 93, are re- ferred to as dry/solid phase substances/materials while the materials indicated by reference number 94 are referred to as drained-of liquid/fluid materials/substances, i.e. water and deicing/ant-icing liquid.

The liquids 95 in the first collection tank 30 may be retrieved for further processing, such that the deicing and/or anti-icing liquids may be extracted and disposed of in an environmentally safe way or recycled.

The unit 10 further comprises at least one exit opening 70, 71 (not shown in Figs. 1-3, but examples are shown in in Fig. 4), through which the solid phase substances/materi- als 93 may be removed. For example, the unit 19 shown in Figs. 1-3 could have a door (not shown) in the upper part of the housing 18 or in a sidewall, allowing an operator access to the filter 15. Thereby, he may brush the filter or shovel dry materials from the filter 15. Also, the filter 15 may be a configured for being releasable from the tray and through an exit opening, whereby solid phase materials 93 thereon could be transported out of the unit 10 (not shown).

Thus, the unit 10 comprise means for separating the solid substances from the fluid substances swept into the sorting tray 13, but may also comprise means (not shown in Fig. 1) for automatically expelling the solid substances from the unit 10. The solid sub- stances are preferably expelled from the unit 10 through an outlet port 70 in the unit 10, preferably formed through a sidewall 19 (Fig. 4) in the housing 18 of the unit 10. The means for separating the solid substances from the fluid substances swept into the sorting tray 13 may, as described above, be a simple horizontal grid/mesh/filter 15, but other means are conceivable. Further below, an alternative active sorting/separation is described in connection with Fig. 2.

The means (not shown in Fig. 1) for expelling the solid substances from the unit 10 may take on several different forms. They may in a simple embodiment (not shown) be formed by a scraper, actuable in a direction towards the above-mentioned outlet port 70. The scraper may be arranged to scrape over the horizontal grid/mesh/filter 15 in embodiments having such a horizontal grid/mesh/filter 15, or a certain predetermined height over the bottom 13' of the sorting tray 13. The scraper may be actuated by suitable means such as linear actuators, or by being arranged on an endless conveyer belt arranged above the sorting tray 13. In alternative embodiments (not shown), the hori- zontal grid/mesh/filter 15 or portions thereof may be configured as an endless conveyor belt with transverse flanges/scrapers, and arranged to transport solids (ice/snow/slush) towards the outlet port 70. In yet further embodiments (not shown), one or more brushes may be configured to expel the dry/solid phase materials via the outlet port 70. Thereby, the solids in the form snow and ice may be separated from the liquid substances, and be expelled from the unit 10, such that only the liquid substance portion 94, swept into the unit 10 are collected in are collected in the bottom of the sorting tray 13 and pumped to the first collection tank 30. As shown in Fig. 1 the baffle 12 may define a depth of the liquid containing part of the sorting tray 13.

The rotatable brush 1 1 is preferably a rotatable horizontal axis generally cylindrical brush 11 as shown in Figs. 1-3. However, in other (not shown) embodiments, the rotat- able brush may alternatively be replaced by a set of vertical axis brushes.

Fig. 2 shows an alternative embodiment of the system 1 according to the invention. The same reference numbers refer to the same parts as in figure 1. As described above, snow and ice collected along with the deicing/anti-icing liquid, is separated from the liquid, and the "dry solid material", i.e. the ice and snow (and some of the de- bris/gravel), is returned to the surface 90, such that only the liquid materials 95 are collected in the first collection tank 30. As shown in Fig. 2 the dry/solid phase materials 93 may be separated from the liquid materials 94 using an auger 16, which compresses the solid phase material, and thereby squeezes the liquid materials 94 from the solid phase material 93, and transports the remaining solid phase materials out of the unit 10 through outlet port 70.

In the Fig. 2 embodiment, the auger 16 (screw conveyor) has a rotation axis perpendicular to the motion of the unit (represented by arrow 50) and parallel to that of the rotating brush 1 1 , which in this example is a rotatable horizontal axis cylindrical brush. The auger 16 is rotatable (indicated by arrow 52) to provide transportation of the dry or solid phase materials (ice, snow) sideways out of the unit 10, through an outlet port 70 (Fig. 4) in a sidewall 19 of the housing of the unit 10, i.e. the solid phase materials 93 are transported in a direction along axis B. Preferably, the outlet port 70 is provided such that it has a lower edge 70', which is formed, such that it has a height substantially corresponding to the height of the baffle 12, in order to prevent liquids to spill out of the outlet port. A filter 15 may further be provided to prevent ice and snow from entering the outlet 14 of the sorting tray 13, and to secure the sorting of the wet and the dry potions of the collected material. The mesh/grid/filter 15 in the Fig. 2 embodiment may be a rounded structure following the cylindrical outer structure defined by the helix of the rotatable screw conveyor/auger 16.

In further embodiments, and as illustrated in Fig. 3, the first collection tank 30 may be supplemented with a second collection tank 31 , or - in not shown further embodiments - with more additional collection tanks. The same reference numbers refer to the same parts as in Figs. 1 and 2.

Thereby, the deicing/anti-icing liquid may be separated, dependent on composition of the deicing/anti-icing liquid, e.g. the glycol concentration of the collected liquid passing through the piping 21 , 22. In this case preferably, the glycol concentration is measured by a sensor 40. In order to control the collection of deicing/anti-icing liquid with different composition (such as glycol concentration), the sensor 40 is further connected to a set of valves, preferably one for each collection tank 30, 31 , i.e. a control valve 41 for first tank 30 and control valve 42 for second tank 31 , respectively. Preferably, the sensor 40 and the valves 41 , 42 are connected via a suitable electronic control system. The sensor 40 is configured for measuring the composition of the liquid passing the sensor 40 and the electronic control system is further configured to control the opening and closing of the valves 41 , 42 according to a predetermined scheme, to fill either of the collection tanks 30, 31 , based on information received from the sensor 40. Thereby an optimized recycling of the deicing/anti-icing liquid may be obtained.

The sensor 40 may measure the composition of the passing liquid continuously or in regular time-intervals. Preferably, the sensor measures a glycol concentration.

Fig. 3 further shows a recovered deicing/anti icing liquid 95 in first collection tank, and a recovered/recovered deicing/anti icing liquid 96 in second collection tank, where the liquids 95 and 96 may e.g. have different concentrations of glycol.

Fig. 4 shows a unit 10 according to the invention. The same reference numbers refer to the same parts as in Figs. 1 , 2 and 3. The unit 10 has rotating brush 1 1 and a baffle (not shown in Fig. 4), and a sorting tray 13. The unit 10 in Fig. 4 is configured as a front- runner to be mounted in front of a vehicle, such as a truck or a tractor, or the like, via a mount 63. The unit 10 has a frame 60 to which the housing 18, rotating brush 11 , baffle (not shown in Fig. 4), and sorting tray 13 is assembled. The frame 60 is further configured with wheels 61 62 to support the unit 10 during use, and secure that the rotating brush, etc. is maintained at a desired level. The unit 10, shown in Fig. 4 is connectable to one or more collection tanks 30, 31 as described above. In this embodiment, the collection tanks 30, 31 , and the pump 20 is preferably located on the vehicle (not shown) and connectable to the unit 10 via a suitable piping (not shown). Also shown in Fig. 4 is the exit port 70 formed in a sidewall 19 of the sorting tray 13. In this embodiment the sorting tray 13 is a closed box shaped structure, defining a housing 18. In order to guide the swept-up materials 91 to an inlet opening 17 (not shown in Fig. 4), the unit 10 further comprises a guard or guide plate 65. Further, Fig. 4 shows access doors 71 providing access to the interior of the housing 18 and the sorting tray 13, in particular to the auger (not shown in Fig 4). However, the access doors 71 also may provide access for an operator of the system 1/unit 10 to manually brush out or shovel away snow/ice/dry materials 93 from the mesh/grid/filter 15 (not shown in Fig. 4) A common feature of the invention is that deicing/anti-icing liquid is brushed/swept up from the surface 90 by a rotating brush 11 , and that the collected deicing/anti-icing liquid as well as ice and snow collected at the same time enters a sorting tray 13, where the liquid materials and the dry/solid phase materials are sorted, and from which the liquid materials may be pumped to one or more collection tanks 31 ,32.

The dry or solid-phase materials (snow, ice and/or grave/debris) may be removed or automatically expelled from the sorting tray 13 and on to the surface 90, from which it was previously swept up.

As may be appreciated from the drawings the sorting tray 13 is level (relative to surface 90) with the rotating brush 1 1 during use. Preferably, the external bottom side 13" of the sorting tray 13 is close to the ground /surface 90 during use, such as 3-100 cm, such as 5-50 cm, such as 5-20 cm, and preferably 5-15 cm above the surface 90, and parallel thereto. In embodiments, where the rotating brush 1 1 is a horizontal axis cylindrical brush, as shown in Figs. 1-4, the external bottom side 13" of the sorting tray 13 is preferably arranged at a location between the surface 90 and the height of the horizontal axis of the cylindrical brush 11. By providing a low location for the sorting tray 13, a very compact deicing/anti-icing recovery unit may be obtained. This also allows to keep the swept-up materials away from heat sources in the machinery, whereby the temperature of the swept-up materials may be maintained at the lowest possible temperature in the sorting tray 13 at least until it has been sorted. This may aid the separation of the liquid/wet and the dry/solid phase materials in the collection tray 13, where the wet materials are deicing/anti-icing liquid and water from melted ice and snow, and where the dry/solid phase materials are snow, ice. Further, providing a low location of the sorting tray 13 secures that the rotational brush 1 1 can lift the liquid/wet and dry/solid phase material 92 into the sorting tray 13, and there is no need for additional transportation of the liquid/wet and dry/solid material 92. Thereby, a more simple, compact and robust unit 10, with fewer movable parts may be obtained, and the energy consumption may be reduced.

Gravel/dirt/debris is preferably expelled with the snow and ice, but dependent on the mesh/grid 15 size, some may accumulate at the bottom of the sorting tray 13 or on the mesh/grid 15. Thereby, the gravel/dirt/debris may be emptied/cleaned via the access doors 71 formed in e.g. a top surface of the unit 10 (Fig. 4). Since airport apron/deicing platform (surface 90) are normally kept very clean from gravel/dirt/debris this is not expected to be necessary very often.

In order to secure that the materials 91 swept from the apron/deicing platform surface 90 enters the sorting tray 13, the upper edge 12" of the baffle 12 preferably is located at a height above the external bottom 13" of the sorting tray 13 of 3-60 cm, such as 3- 20 cm and preferably 3-15 cm. The upper edge 12" of the baffle 12 is parallel to the surface 90 (horizontal) during use of the unit 10. The baffle is preferably comprises an inclined plate/flange that forms a slope for the materials 92 entering the sorting tray. The lower edge 12' of the baffle may - in not shown embodiments - extend below the external bottom 13" of the sorting tray 13. The lower edge 12' of the baffle 12 is parallel to the surface 90 (horizontal) during use of the unit 10.

It will be appreciated that the sorting tray 13 and the baffle 12, the means for sorting 15 and the means for expelling 16 are formed in the housing 18. The rotating brush 1 1 may be enclosed in the housing as shown in Figs. 1-3 (only a part of the rotating brush extending through an inlet opening 17 through the bottom 18' of the housing 18). In other embodiments, and e.g. as illustrated in Fig 4, the rotating brush 11 is connected to the frame in connection with an inlet opening (not shown in Fig. 4) in the housing formed at the baffle 12. The inlet opening 17 to the housing 18 therefore in either case functions as an inlet opening to the sorting tray 13.

The teaching of this invention has numerous advantages. Different embodiments or implementations may yield one or more of the following advantages. It should be noted that this is not an exhaustive list and there may be other advantages which are not described herein.

Moreover, due to its flexibility and limited space requirement, the system, unit and method according to the invention may be utilized in combination with already existing equipment such as trucks or tractors, which do not already have a deicing liquid recovery system or unit.

In all the previously described embodiments a heating member (not shown) may be applied in the outlet 14 from the sorting tray 13 in order to prevent the outlet 14 from freezing/clogging, if the freezing temperature of the collected liquid 94 is higher than the ambient temperature. Although the teaching of this application has been described in detail for purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the scope of the teaching of this application.

The term "comprising" as used in the claims does not exclude other elements or steps. The term "a" or "an" as used in the claims does not exclude a plurality. The single processor or other unit may fulfill the functions of several means recited in the claims.

List of reference numbers

A axis of rotatable horizontal axis cylindrical brush

B axis of auger

I deicing/anti-icing-liquid recovery system

10 deicing/anti-icing-liquid recovery unit

I I Rotatable brush, rotatable horizontal axis cylindrical brush

12 baffle

13 sorting tray

13' internal bottom of the sorting tray

13" external bottom side of the sorting tray

14 outlet from the sorting tray

15 Filter

16 expulsion mechanism, auger/screw conveyor

17 inlet opening in housing

18 housing

18' bottom of housing

19 sidewall of housing

20 pump

21 piping

22 piping

30 first collection tank

31 second collection tank

40 Sensor for glycol concentration measurement

41 control valve for first tank

42 control valve for second tank

50 arrow indicating movement of deicing/anti-icing-liquid recovering unit during use

51 arrow indicating rotational direction of rotatable brush

52 arrow indicating rotational direction of auger

60 frame of deicing/anti-icing-liquid recovering unit

61 wheel

62 wheel

63 coupling means

65 guard or guide plate

70 exit port through housing

71 access doors, exit port through housing

90 surface of airport apron/deicing platform at deicing-station or gate surplus deicing/anti icing liquid, ice, water, snow, slush, debris, gravel on surface of airport apron/deicing platform

surplus deicing/anti icing liquid, ice, water, snow, slush, debris, gravel from surface of airport apron/deicing platform being brushed over baffle and into sorting tray

ice, snow, slush, debris, gravel accumulated in sorting tray

deicing/anti icing liquid, water, debris, gravel in sorting tray

recovered deicing/anti icing liquid in first collection tank

recovered deicing/anti icing liquid in second collection tank.