Abstract:
A method of repelling animals from an area which includes the step of causing at least one flexible tube to move, at least within part of the area, by means of a pressurised fluid.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to a method of and apparatus for repelling animals from a given area.  
         [0002]     The invention is described hereinafter with particular reference to repelling animals such as birds from an area such as an airport in an aircraft hanger or other building, on external surfaces eg. ledges or balconies in a building, from agricultural areas eg. vineyards, orchards etc, and from sports fields such as golf courses and the like. The scope of the invention is not confined to these particular applications which are given by way of examples only. Generally the principles of the invention are applicable to repelling animals (birds or ground animals) from an area which is in the open or inside or on a building.  
         [0003]     The presence of birds at an airport constitutes a significant safety hazard to aircraft which are landing at, or taking off from, the airport. A typical airport extends over a substantial area and can have a large number of runways laid out in different directions over the area. Vegetation, typically grass, is established or naturally grows on the surfaces between runways. This vegetation can play host to a variety of animals and, in particular, to birds which, with the passage of time, can establish themselves and form large colonies.  
         [0004]     If an aircraft which is landing or taking off at a runway collides with a bird or a flock of birds, or draws one or more birds into its air intake to one of its engines, the consequences can be disastrous.  
         [0005]     Much effort has been expended in attempts to repel birds from an airport and, more particularly, from ground which is adjacent runways. Diverse techniques exist including noise generators, scarecrows, ultrasonic transmitters, electrical devices which apply mild electric shocks, electrically operated scarecrows and the like. It has been found that although these devices may, at least initially, be effective they are often not effective against all bird species but, more importantly, with the passage of time habituation lessens the effectiveness of the devices. Habituation is the waning of responsiveness to a deterrent which occurs when birds learn that the deterrent, as a matter of fact, does not present danger.  
         [0006]     Although it may be possible to control bird populations by killing the birds this may be undesirable from an environmental point of view. This approach can also lead to a public outcry.  
         [0007]     A related problem presents itself in hangers and other lofty buildings in or on which birds can seek sanctuary effectively protected by the substantial distance which exists between humans, on the ground, and the perches of the birds. Droppings from these birds can cause serious damage to equipment and machinery, mar a building and can constitute a serious health hazard.  
       SUMMARY OF INVENTION  
       [0008]     The invention provides in the first instance a method of repelling animals from an area which includes the step of causing at least one device to move, at least within part of the area, by means of a pressurised fluid.  
         [0009]     The device may be caused to move substantially randomly, or in a predetermined manner.  
         [0010]     The time at which the device is caused to be moved may be varied, according to requirement.  
         [0011]     The pressurised fluid may comprise any suitable pressurised fluid and for example may comprise compressed air.  
         [0012]     One or more substances may be entrained in the pressurised fluid. The substance could for example be selected from the following: water, sand, mud and the like.  
         [0013]     The invention is not limited in this regard. The device may be flexible and may be caused to move with a whip action due to the pressurised fluid which flows through the device.  
         [0014]     The pressurised fluid may be allowed to escape from the device through one or more nozzles which may be shaped to cause a reaction force which helps to cause movement of the device.  
         [0015]     The device may be caused to rotate around an axis.  
         [0016]     A plurality of the devices may be actuated so that they are simultaneously caused to move, or so that they are caused to move in succession in a predetermined sequence, or randomly.  
         [0017]     The invention also provides apparatus for repelling animals from an area which includes a device with an inlet which is adapted to be connected to a source of pressurised fluid and which is constructed so that it is movable by application of the pressurised fluid to the inlet.  
         [0018]     The pressurised fluid is preferably compressed air.  
         [0019]     The device may include a tube. The tube may be elongate and flexible. The tube may include one or more outlet nozzles through which pressurised fluid escapes from the tube. These nozzles may be oriented to assist in causing movement of the tube.  
         [0020]     Alternatively, in the case in which the tube is flexible, the tube may be caused to move, substantially in a random manner, by the flow of compressed air through the tube.  
         [0021]     Means may be provided for entraining a substance into the flow of pressurised fluid through the tube. The substance may be sand, water, mud or the like.  
         [0022]     In one form of the invention the device is caused to rotate around a fixed axis.  
         [0023]     The device may be elevated, at least to a limited extent, upon application of the pressurised fluid to the inlet and it may be allowed, to settle, under gravity or other action, to an inoperative position when the pressurised fluid is not applied to the inlet.  
         [0024]     The invention also extends to a system which includes a network, a plurality of the devices which are connected to the network, a source of pressurised fluid and a control unit, for applying the pressurised fluid, via the network, to one or more of the devices.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]     The invention is further described by way of examples with reference to the accompanying drawings in which:  
         [0026]      FIG. 1  is a schematic plan view of an airfield in which the method of the invention is used for repelling birds from areas adjacent runways at the airfield;  
         [0027]      FIGS. 2, 3  and  4  respectively illustrate different devices which are usable in the method of the invention; and  
         [0028]      FIG. 5  illustrates a system for repelling animals in a diagrammatic form. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0029]      FIG. 1  of the accompanying drawings illustrates in plan an airfield  10  which includes a plurality of runways  12 . Only one runway is shown in the drawing and it is to be understood that other runways at the airfield are treated in substantially the same way as what is described hereinafter.  
         [0030]     The runway  12  is normally formed from concrete or a similar hardwearing surface. An aircraft  14  may traverse the runway in either direction. These aspects are known in the art and are not further described herein.  
         [0031]     Ground  16  adjacent the runway  12  comprises bare earth over which vegetation, not shown, is established. Typically this vegetation includes one or more varieties of grass, as has been described hereinbefore. The vegetation may play host to one more species of birds or other animals and these animals could present a safety hazard to the aircraft  14 .  
         [0032]     An air distribution network is constructed from main pipelines  18  which are buried in the ground, on each side of the runway  12 , at a suitable depth. At intervals along the length of each line  18  a riser tube  20  is connected to the line. Each tube terminates in a housing  22  which contains a connector and a solenoid valve. A flexible tube  24  is fixed to the connector and extends in a random manner from the connector. The tube  24  has a length which ensures that it cannot overlay a portion of the runway  12 .  
         [0033]     A compressed air source  26  is connected to the main line  18 . Depending on the situation the compressed air source may comprise a large pressure vessel or a dedicated air compressor with an optimal storage tank. If appropriate use can be made of both devices. An intention in this regard is that the compressed air source should work at a controlled pressure and supply sufficient compressed air to the line  18  to activate one or more of the hoses  24  in a manner which is described hereinafter.  
         [0034]     The compressed air source is under the control of a control unit  28 . The various solenoid valves at each riser tube  20  are connected by means of lines  30  to the control unit  28 .  
         [0035]      FIG. 2  illustrates one of the flexible tubes  24 . The tube is coupled to a connector  32  which is fixed to the corresponding housing  22  in which is installed a solenoid valve  34 . The riser tube  20  extends from the main line  18  which, as noted, is buried in the ground at a desired depth  36 .  
         [0036]     If compressed air, designated by means of an arrow  40 , is applied to the main line  18 , from the source  26 , and the solenoid valve  34  is opened then the compressed air flows through the flexible hose  24 . Depending on the pressure and the characteristics of the hose the flow of air, through the hose, can cause the hose to move with a whip action in a substantially random manner. If the ground  16  adjacent the runway  12  is to be cleared of animals and, in particular, birds, then the compressed air  40  is applied to the various hoses  24  in a manner which is determined by a program in the control unit  28  which causes the corresponding solenoid valves  34  to open and close as required. The hoses can be caused to move in a fairly vigorous manner which is not predictable and the sequence in which the hoses are activated can also be varied in a non-predictable manner. Birds in the vegetation adjacent the runway are thereby repelled and the area adjacent the runway is freed of bird life. The safety of the aircraft  14  is therefore considerably enhanced.  
         [0037]     The repelling apparatus of the invention can be operated at different intervals, on an ongoing basis, or it can be operated before an aircraft takes off from, or lands on, the runway  12 . Some degree of experimentation may be required in order to ascertain the most effective way, under the circumstances, of making use of the invention.  
         [0038]      FIG. 2  illustrates a vessel  42  with an outlet conduit  44  which is connected to the line  18 . The vessel may contain water, sand, mud  46  or any other appropriate substance. When air flows through the main line  18  a portion of the substance in the vessel is entrained into the air flow and is distributed through an outlet end  48  of the flexible hose  24 . If the substance  46  is, for example, sand then the sand is ejected from the end  48  at high speed, depending on the velocity of the escaping air, and this can add to the deterrent effect of the hose which is flexing to and fro.  
         [0039]      FIG. 3  illustrates a variation which can be incorporated in the apparatus shown in  FIG. 1 . Inflatable scarecrows  50  are connected to the line  18  at regular intervals. The scarecrows can be inflated by the compressed air and when this happens each scarecrow, which is initially in a collapsed state, is caused to move to an erect position in a short time. The sudden movement can assist in repelling birds from a given area. The inflation of each scarecrow is controlled by means of the control unit  28  which is connected via a control line  30  to a solenoid valve  34  which controls the flow of air from the line  18  to the scarecrow figure. If the inflation of the scarecrow is associated with the actuation of a hose  24 , by animals in the area, then air usage may be reduced if the hose is not actuated every time the scarecrow is inflated.  
         [0040]      FIG. 4  illustrates a further variation of the invention. Each housing  22  is formed in the nature of a “pop-up” device  60  similar to a pop-up sprinkler used in an irrigation system. Thus the housing includes a tubular body  62  which contains a swivel connector  64  which is mounted to a riser tube  20  in sliding fashion. When compressed air is applied to the swivel connector the resulting force causes the swivel connector to rise along the length of the tube  20  and the corresponding end of the hose  24  which is coupled to the connector is elevated. When the supply of compressed air is disconnected from the swivel connector air escapes from the swivel connector which then settles under gravity action, into the tubular casing  62 . This arrangement has a number of benefits. Firstly it allows the tube  24  to be elevated when air is applied to it. The degree of elevation can be controlled so that the tube is lifted above the grass which may be growing on the ground  16  adjacent the runway. Secondly when the device is not being used it settles into the ground and thus does not present any obstruction to traffic over the ground  16 .  
         [0041]     A further modification is shown in  FIG. 4 . The tube  24  which may be highly flexible or substantially rigid has one or more nozzles  66  at its outlet end  48 . These nozzles are shaped so that air escaping from the nozzles exerts a reaction force on the tube  24  which causes it to rotate about the swivel connector  64  as is indicated by means of a curved arrow  68 . The tube can be caused to rotate fairly rapidly and vigorously so that birds adjacent the tube are repelled from the vicinity of the tube.  
         [0042]     The period for which the tube  24  is caused to move, and the time interval between successive actuations of the tube, may be varied to achieve optional results.  
         [0043]     It is to be understood that the apparatus of the invention is not intended to cause injury to birds but, instead, is designed to make conditions adjacent the runway unacceptable to bird life. As the hoses move vigorously it is possible, however, for the hoses to cause injury to birds. This can be a positive factor though, for a learning process sets in. The birds associate the moving hoses with danger and are therefore likely to fly away from the areas in which the hoses are installed and used.  
         [0044]      FIG. 5  is a generalised representation of an animal repelling system  70  according to the invention based on the preceding principles. The system includes a compressor or compressed air source  72  which is connected to a plurality of solenoid valves  74 A,  74 B,  74 N by means of an air distribution network  76  formed, for example, from plastic tubing. Each solenoid is used to control the supply of air from the network to a respective flexible plastic tube  78 A,  78 B, . . . .  78 N.  
         [0045]     A control unit  80 , which may be a micro processor-based device such as a programmable logic controller, is used to control the actuation of the various solenoid valves. The control unit is connected to a power supply  82  of any appropriate type and is connected to the solenoid valves via a cable network  84  which may for example be a two or three wire network.  
         [0046]     Each of the solenoids  74  includes a respective decoder  86 A,  86 B . . .  86 N, and a respective unique code is associated with each of the solenoids.  
         [0047]     The control unit is programmed to generate, at any time, one or more of the codes which are associated with the solenoids. The codes can be generated in a controlled sequence so that, for example, the codes associated with the solenoids  74 A,  74 B . . .  74 N are generated in that sequence. Alternatively the codes can be generated in a random or pseudo-random fashion. The latter course of action is preferable in that it then becomes practically impossible, particularly for an animal, to predict which solenoid will be actuated at any time.  
         [0048]     The codes which are generated by the control unit  80  are presented simultaneously via the cable network  84  to the decoders  86 . If a code on the cable network is validated by a respective decoder then the solenoid associated with that decoder is actuated and the remaining solenoids are kept closed. Power from the supply  82  is transmitted over the network  84  and is used to energise the selected solenoid.  
         [0049]     As has been noted hereinbefore when a solenoid is opened air from the compressed air source in the system is vented to atmosphere through the respective tube  78  and the release of energy in the compressed air, flowing through the tube, causes the tube to flex and move substantially randomly through the air. This acts as a significant deterrent for, at the same time, a fair amount of noise is generated as air escapes from the tube. Depending on the pressure the compressed air can cause the respective tube  78  to move violently and it is possible for the tube to injure or kill a small animal. On the other hand by adjusting the air pressure the vigorous movement of the hose  78  can be attenuated, if required.  
         [0050]     A system  70  of the kind shown in  FIG. 5  can be installed at any appropriate location for example inside a building such as a hanger, on rafters of the building, outside a building on ledges or balconies or other locations at which birds are prone to congregate, on a golf course, particularly at the putting greens which should be protected from large numbers of birds, and in agricultural installations such as at orchards, vineyards and the like.