Abstract:
An aircraft de-icing system has a nozzle with at least one movable element configured to move between a first position and a second position to change a spraying configuration of the nozzle between a first configuration and a second configuration. The aircraft de-icing system further has at least one storage reservoir configured for containing a de-icing agent and a pump for pumping the de-icing agent from the at least one storage reservoir to the nozzle. The aircraft de-icing system further has a pressurized air source in fluid communication with the nozzle for delivering pressurized air to the nozzle. The nozzle is configured for selectively mixing varying amounts of the pressurized air and varying amounts of the de-icing agent to provide a spray pattern for application on a surface of an aircraft based on a position of the at least one movable element between the first position and the second position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Provisional U.S. Application No. 62/174,139, filed on Jun. 11, 2015 and titled “Adjustable Forced Air Aircraft Deicing System”, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The present invention relates generally to systems and methods for de-icing aircraft, and more particularly to a system and method for the forced air de-icing of aircraft with an adjustable forced de-icing system. 
         [0004]    Description of the Related Art 
         [0005]    De-icing of aircraft involves removing snow, ice, and/or frost from various surfaces of the aircraft. De-icing is traditionally performed by spraying dry or liquid chemicals on the aircraft. In some examples, a heated mixture of a de-icing agent, such as antifreeze (or glycol), and water is sprayed by pressurized air through a nozzle provided on a movable boom secured on a stationary or mobile platform. Examples of known de-icing systems and methods are described in U.S. Pat. No. 5,244,168, U.S. Pat. No. 5,755,404, and U.S. Pat. No. 6,250,588. These de-icing systems and methods use a fixed nozzle in fluid communication with a fixed supply of the de-icing agent and pressurized air. The de-icing agent and pressurized air are mixed in the nozzle and delivered from the nozzle as a jet of pressurized de-icing agent. 
         [0006]    Conventional de-icing systems are configured for fixed nozzle operation. In other words, the nozzle has a fixed aperture (i.e., not adjustable) and the jet velocity is determined by air source or compressor/blower speed that delivers pressurized air at a fixed flow rate. The optimal jet velocity is attained when a compressor/blower used to deliver the air delivers a pressure ratio of about two, resulting in a jet velocity of about 1,000 ft/sec at the nozzle exit. Effectiveness of conventional forced air de-icing systems is primarily dependent on the velocity of the jet downstream of the nozzle exit. The higher the jet velocity, the more pressure and force is imparted to the aircraft surface to remove ice and snow. The jet velocity typically decays rapidly as the forced air stream mixes with the surrounding air. Some de-icing systems have the capability to reduce the power to the compressor/blower and hence nozzle exit velocity; however, such operation is still based on using a fixed nozzle with a diminished jet velocity at increased distance. 
         [0007]    While conventional de-icing systems and methods are effective in removing snow, ice, and/or frost, they are associated with a number of disadvantages. Weather conditions during de-icing operations often change continuously such that a jet delivered from a fixed nozzle rarely performs in an optimum manner to maximize the de-icing efficiency while minimizing use of the de-icing agent. Also, overblow of snow from the aircraft reduces visibility around the aircraft, thereby creating a hazard for ground workers. Conventional de-icing systems require the operator to get close to the aircraft (typically five to ten feet) to maintain an effective snow and ice removal capability of the fixed nozzle which rapidly diminishes if the distance between the nozzle and the aircraft is increased. In addition, noise generated by conventional fixed nozzles is often close to or exceeds the permissible noise limit that is enforced at various airports. 
         [0008]    It would be desirable to develop new systems and methods for de-icing aircraft that overcome the deficiencies associated with conventional de-icing systems and methods. 
       SUMMARY OF THE INVENTION 
       [0009]    In view of the disadvantages of prior art de-icing systems, it is desirable to provide an improved de-icing system having an adjustable forced air nozzle. It would be further desirable to provide an improved de-icing system having an adjustable forced air nozzle that remains effective in all weather conditions and/or at various distances of the nozzle from the, aircraft. It would be further desirable to provide an improved de-icing system configured to reduce consumption of the de-icing agent and reduce overall noise emitted by the nozzle. It would be further desirable to provide a system having an adjustable forced air nozzle that is configured for washing a surface of an aircraft using, for example, a cleaning solution. 
         [0010]    In some examples, an aircraft de-icing system may include a nozzle with at least one movable element configured to move between a first position and a second position to change a spraying configuration of the nozzle between a first configuration and a second configuration. The aircraft de-icing system further may have at least one storage reservoir configured for containing a de-icing agent and a pump for pumping the de-icing agent from the at least one storage reservoir to the nozzle. The aircraft de-icing system further may have a pressurized air source in fluid communication with the nozzle for delivering pressurized air to the nozzle. The nozzle may be configured for selectively mixing varying amounts of the pressurized air and varying amounts of the de-icing agent to provide a spray pattern for application on a surface of an aircraft based on a position of the at least one movable element between the first position and the second position. 
         [0011]    In some examples, the nozzle may have a nozzle body having a proximal end, a distal end, and a sidewall extending between the proximal end and the distal end along a longitudinal axis. The nozzle may also have a plug within at least a portion of the nozzle body at the distal end of the nozzle body, and a cowl surrounding at least one of the nozzle body and the plug. The cowl may be movable relative to the nozzle body in a direction along the longitudinal axis. The cowl may have a first portion having an inner diameter that is larger than an outer diameter of the nozzle body, and a second portion extending distally from the first portion. The second portion may have a conical shape that gradually narrows in diameter in a direction from the proximal end to the distal end of the nozzle body and terminates in an open end. An inner surface of the second portion of the cowl and an outer surface of the distal end of the plug may define an annular space such that movement of the cowl relative to the nozzle body changes a cross-sectional area of the annular space. The cross-sectional area of the annular space may increase as the cowl is moved in a direction from the proximal end of the nozzle body toward the distal end of the nozzle body, and the cross-sectional area of the annular space may decrease as the cowl is moved in a direction from the distal end of the nozzle body toward the proximal end of the nozzle body. A drive mechanism may be provided for moving the cowl relative to the nozzle body. A seal may be provided between an inner surface of the cowl and an outer surface of the nozzle body. 
         [0012]    In some examples, the plug may have a rounded proximal end and a conical distal end that gradually reduces in cross-sectional area in a direction from the proximal end toward the distal end. The plug may be attached to an inner surface of the sidewall of the nozzle body by one or more struts that extend in a radially outward direction from an outer surface of the plug to an inner surface of the sidewall of the nozzle body. At least a portion of the plug may extend distally from a terminal end of the nozzle body. The plug may have a first portion fixed relative to the nozzle body and the cowl, and a second portion movable relative to the first portion from a first position to a second position in a direction along the longitudinal axis. A drive mechanism may be provided for moving the second portion of the plug relative to the first portion of the plug. A seal may be provided between the first portion of the plug and the second portion of the plug. A controller may be configured for controlling a delivery of the de-icing agent and pressurized air to the nozzle. The controller may be configured to recall a pre-programmed spray protocol, and adjust the nozzle and the delivery of the pressurized air and the de-icing agent to the nozzle based on the pre-programmed spray protocol. 
         [0013]    In some examples, a nozzle for an aircraft de-icing system may include a nozzle body having a proximal end, a distal end, and a sidewall extending between the proximal end and the distal end along a longitudinal axis, and a cowl surrounding the nozzle body and movable relative to the nozzle body in a direction along the longitudinal axis. The cowl may have a first portion having an inner diameter that is larger than an outer diameter of the nozzle body, and a second portion extending distally from the first portion. An inner surface of the first portion of the cowl and an outer surface of the distal end of the nozzle body may define an annular space. A cross-sectional area of the annular space may increase as the cowl is moved in a direction from the proximal end of the nozzle body toward the distal end of the nozzle body, and the cross-sectional area of the annular space may decrease as the cowl is moved in a direction from the distal end of the nozzle body toward the proximal end of the nozzle body. The nozzle may be configured for selectively mixing varying amounts of pressurized air and a de-icing agent to provide a spray pattern for application on a surface of an aircraft based on a position of the cowl relative to the nozzle body. A drive mechanism may be provided for moving the cowl relative to the nozzle body. 
         [0014]    In some examples, a nozzle for an aircraft de-icing system may have a nozzle body having a proximal end, a distal end, and a sidewall extending between the proximal end and the distal end along a longitudinal axis, and a plug within at least a portion of the nozzle body at the distal end of the nozzle body. The plug may have a first portion fixed relative to the nozzle body, and a second portion movable relative to the first portion from a first position to a second position in a direction along the longitudinal axis. The nozzle may have a cowl surrounding at least one of the nozzle body and the plug. An inner surface of the second portion of the cowl and an outer surface of the distal end of the plug define an annular space. A cross-sectional area of the annular space may increase as the cowl is moved in a direction from the proximal end of the nozzle body toward the distal end of the nozzle body, and the cross-sectional area of the annular space may decrease as the cowl is moved in a direction from the distal end of the nozzle body toward the proximal end of the nozzle body. The nozzle may be configured for selectively mixing varying amounts of pressurized air and a de-icing agent to provide a spray pattern for application on a surface of an aircraft based on a position of the first portion of the plug relative to the second portion of the plug. A seal may be provided between an inner surface of the cowl and an outer surface of the nozzle body. 
         [0015]    In some examples, the nozzle may be infinitesimally adjustable between the high pressure, low volume mode and the low pressure, high volume mode. The nozzle may have a plurality of finite adjustments between the high pressure, low volume mode and the low pressure, high volume mode. A heater may be provided for heating the de-icing agent before the de-icing agent is delivered to the nozzle. The pressurized air source may be an air compressor. The pressurized air source may have an air heater. A movable boom may be provided, and the nozzle may be mounted to the movable boom such that the nozzle is movable with a movement of the boom. 
         [0016]    These and other features and characteristics of the aircraft de-icing system and various nozzles for use with the aircraft de-icing system described herein, as well as the methods of manufacture of such articles, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only. As used in the specification and the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a representative schematic view of an ADS in accordance with a one preferred and non-limiting example of the present invention; 
           [0018]      FIG. 2A  is a representative cross-sectional side view of a nozzle for use with an ADS in accordance with one example shown in a first configuration; 
           [0019]      FIG. 2B  is a representative cross-sectional side view of the nozzle of  FIG. 2A  shown in a second configuration; 
           [0020]      FIG. 3A  is a representative cross-sectional side view of a nozzle for use with an ADS in accordance with another example shown in a first configuration; 
           [0021]      FIG. 3B  is a representative cross-sectional side view of the nozzle of  FIG. 3A  shown in a second configuration; 
           [0022]      FIG. 4A  is a representative cross-sectional side view of a nozzle for use with an ADS in accordance with another example shown in a first configuration; 
           [0023]      FIG. 4B  is a representative cross-sectional side view of the nozzle of  FIG. 4A  shown in a second configuration; and 
           [0024]      FIG. 5  is a representative graph illustrating a change in velocity of a fluid jet exiting a nozzle as a function of distance away from the nozzle. 
       
    
    
       [0025]    In  FIGS. 1-5  the same characters represent the same components unless otherwise indicated. 
       DETAILED DESCRIPTION 
       [0026]    As used herein, spatial or directional terms, such as “left”, “right”, “up”, “down”, “inner”, “outer”, “above”, “below”, and the like, relate to various features as depicted in the drawing figures. However, it is to be understood that various alternative orientations can be assumed and, accordingly, such terms are not to be considered as limiting. 
         [0027]    As used herein, the term “substantially parallel” means a relative angle as between two objects (if extended to theoretical intersection), such as elongated objects and including reference lines, that is from 0° to 5°, or from 0° to 3°, or from 0° to 2°, or from 0° to 1°, or from 0° to 0.5°, or from 0° to 0.25°, or from 0° to 0.1°, inclusive of the recited values. As used herein, the term “substantially perpendicular” means a relative angle of intersection between two objects that is 90°+/−5°, or from 90°+/−3°, or from 90°+/−2°, or from 90°+/−1°, or from 90°+/−0.5°, or from 90°+/−0.25°, or from 90°+/−0.1°, inclusive of the recited values. 
         [0028]    Unless otherwise indicated, all ranges or ratios disclosed herein are to be understood to encompass any and all subranges or subratios subsumed therein. For example, a stated range or ratio of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges or subratios beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less, such as but not limited to, 1 to 6.1, 3.5 to 7.8, and 5.5 to 10. 
         [0029]    Unless otherwise indicated, all numbers expressing quantities used in the specification and/or claims are to be understood as modified in all instances by the term “about.” 
         [0030]    As used herein, the phrase “de-icing agent” means a fluid that is used for de-icing (i.e., removal of snow, ice, frost, etc.) an aircraft or anti-icing (preventing formation of snow, ice, frost, etc.) on an aircraft. 
         [0031]    All documents, such as but not limited to issued patents and patent applications, referred to herein, and unless otherwise indicated, are to be considered to be “incorporated by reference” in their entirety. 
         [0032]    Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, the present disclosure is generally directed to an aircraft de-icing system  10  (hereinafter “ADS”) configured for removing snow, ice, and/or frost from various surfaces of an aircraft, as described herein. Various examples discussed herein are directed to one or more nozzles configured for use with the ADS  10 . In various examples, such nozzles are in fluid communication with a source of pressurized air and a source of de-icing agent. Furthermore, the present disclosure provides various nozzles for adjusting a jet of pressurized air and de-icing agent mixture exiting the nozzle. 
         [0033]    With initial reference to  FIG. 1 , the ADS  10  includes a base  12  having a boom  14  with a nozzle  16  mounted at a terminal end thereof. In some examples, the base  12  may be a movable base, such as a truck, that may be moved around an aircraft  18  to position the boom  14 , along with the nozzle  16 , at a desired position such that pressurized de-icing agent may be sprayed onto the aircraft  18  through the nozzle  16 . The boom  14  may be fixed or movable to aid in positioning the nozzle  16  at a desired position relative to the aircraft  18 . In other examples, the base  12  may be a stationary or fixed base with a movable boom  14 . The movable boom  14  provides an advantage of positioning the nozzle  16  more closely to the aircraft  18  without fear of the possibility of collision damage to the aircraft  18 . In various aspects, the nozzle  16  may be movable relative to the boom  14 . 
         [0034]    With continued reference to  FIG. 1 , the ADS  10  is associated with a de-icing agent storage reservoir  20  in fluid communication with the nozzle  16  for delivering the de-icing agent to the nozzle  16 . In some examples, the storage reservoir  20  may be configured for storing a cleaning solution used for washing aircraft. At least one pump  22  may be provided to deliver the de-icing agent from the storage reservoir  20  to the nozzle  16 . The delivery parameters, such as the flow rate of the de-icing agent, may be adjusted according to the specific snow or icing conditions on the surface of the aircraft  18 . In some examples, the ADS  10  may be associated with a plurality of storage reservoirs  20  for storing different de-icing agents. Each of the plurality storage reservoirs  20  may have at least one pump  22 , or a single pump  22  may be selectively placed in fluid communication with one or more of the plurality of storage reservoirs  20 . In various examples, the de-icing agent may be a “Type I” fluid for de-icing (low viscosity, unthickened fluid) or a “Type IV” fluid for anti-icing (high viscosity, thickened fluid). The ADS  10  may deliver a mixture of one or more different de-icing agents to the nozzle  16 . In various examples, the de-icing agent may be heated while in the storage reservoir  20  and/or while en route to the nozzle  16 . A separate heater  24  may be provided for heating the de-icing agent, as determined by the operator based on the icing conditions. Desirably, the heater  24  is configured to heat the de-icing agent to a desired temperature as fast as the de-icing agent is pumped by the pump  22 . 
         [0035]    With continued reference to  FIG. 1 , the ADS  10  is further associated with a pressurized air source  26 . The pressurized air source  26  may be a compressor configured for pressurizing ambient air to an elevated pressure, such as at a pressure ratio of about two. The pressurized air source  26  is in fluid communication with the nozzle  16  for delivering the pressurized air to the nozzle  16 . The pressurized air source  26  may deliver pressurized air to the nozzle  16  at a constant or variable flow rate. Desirably, the pressurized air source  26  has an adjustable flow rate to deliver an optimum flow rate of pressurized air to the nozzle  16  depending on the de-icing conditions and a configuration of the nozzle  16 . 
         [0036]    In various examples, the ADS  10  may have a controller  30  for controlling the delivery of the de-icing agent and pressurized air to the nozzle  16 . The controller  30  may control the temperature of the de-icing agent by controlling the operation of the heater  24 . The controller  30  may also control the pressure and volume of the de-icing agent by controlling the operation of the pump  22 . In addition, the controller  30  may control the pressure and flow rate of pressurized air by controlling the operation of the pressurized air source  26 . In various examples, the controller  30  may adjust the mixture of the de-icing agent and pressurized air, such as by controlling the temperature, volume, and/or flow rate of the de-icing agent and/or pressurized air. The controller  30  may receive temperature, flow rate, and/or pressure data from one or more sensors (not shown). The controller  30  may be provided as a standalone unit, or it may be incorporated into one of the components of the ADS  10 . The controller  30  may be configured or programmed to recall a pre-programmed spray protocol for a specific de-icing procedure. In some examples, the user may modify a selected pre-programmed spray protocol. 
         [0037]    The controller  30  may be connected to a display  32  which may be positioned in a control room or cabin of the ADS  10 . The display  32  is operative to present a user interface, such as a graphical user interface (GUI), for accessing information and to perform functions associated with the operation of the ADS  10 . For example, the GUI interface may provide volume information of the amount of the de-icing agent in the storage reservoir  20 . The GUI interface may also provide temperature and pressure information of the de-icing agent and/or pressurized air that is delivered to the nozzle  16 . The GUI interface may also allow the user to control a spray pattern of the nozzle  16  and allow adjustments of the flow rate and pressure of the de-icing agent and/or pressurized air that is delivered to the nozzle  16 . In one example, the display  32  may be a touch sensitive display including virtual keys and buttons for data entry, such as alphanumeric keys and symbolic keys. 
         [0038]    Heated or unheated de-icing agent is mixed with pressurized air within the nozzle  16  to provide a desired a predetermined spray pattern of an air-entrained de-icing agent. The de-icing agent becomes entrained in the high velocity air stream within the nozzle  16  such that the entrained fluid can then be formed into a spray pattern and delivered from the tip of nozzle  16 . hi some examples, heated or unheated cleaning solution is mixed with pressurized air within the nozzle  16  to provide as desired a predetermined spray pattern of air-entrained cleaning solution for washing a surface of the aircraft  18 . 
         [0039]    Having described the structure and functionality of the ADS, the structure of various examples of the nozzle  16  will now be described. In various examples, the nozzle  16  may be configured for operation in a high pressure, low volume mode and a low pressure, high volume mode. The nozzle  16  may have a number of finite adjustments between these two modes. In some examples, the nozzle  16  may be infinitesimally adjustable between these two modes, or the nozzle  16  may have a plurality of finite adjustments between the two modes. In the high pressure, low volume mode, the nozzle  16  is configured to provide the highest jet exit velocity. In use, the high pressure, low volume delivery of the de-icing mixture may be used for breaking adhesion between snow/ice and the surface of the aircraft  18 . The high pressure jet is sustained in close proximity to the exit of the nozzle  16  (approximately 1 to 3 feet). On the other hand, the low pressure, high volume mode provides a reduced jet velocity at the exit of the nozzle  16  but the pressure of the jet decays less rapidly with the distance away from the exit of the nozzle  16 . In this manner, the low pressure, high volume mode can be used for sweeping loose snow/ice from the surface of the aircraft  18  at greater distances. Due to the lower jet exit velocity, the low pressure, high volume mode may also be used with Type IV fluid and projected onto the surface of the aircraft  18  from greater distances. 
         [0040]    With reference to  FIGS. 2A-2B , the nozzle  16  is shown in accordance with one preferred and non-limiting example of the present invention. The nozzle  16  has a nozzle body  34 , a plug  36  within at least a portion of the nozzle body  34 , and a cowl  38  surrounding the nozzle body  34  and/or plug  36 . In some examples, the nozzle body  34  is formed as a cylindrical conduit having a proximal end  40  and a distal end  42  with a sidewall  44  extending therebetween along a longitudinal axis  46 . Pressurized air from the pressurized air source  26  (shown in  FIG. 1 ) is delivered through the nozzle body  34  in a direction from the proximal end  40  toward the distal end  42 , as shown by the arrow A in  FIGS. 2A-2B . A fluid inlet  48  is configured to deliver the de-icing agent to the nozzle  16  for mixing with the pressurized air. In one example, the fluid inlet  48  may be at the proximal end  40  of the nozzle body  34  and extends through the sidewall  44  of the nozzle body  34 . In another example, the fluid inlet  48  may be at or near the plug  36 . In yet another example, the fluid inlet  48  may be external to the nozzle body  34  at the distal end  42  of the nozzle body  34 . In this example, the de-icing agent is delivered by gravity to a stream of pressurized air to become entrained with the stream, thereby forming a jet of pressurized air/de-icing fluid mixture. 
         [0041]    With continued reference to  FIGS. 2A-2B , the plug  36  may have a bulbous shape that narrows in a direction from the proximal end  40  toward the distal end  42 . The plug  36  may have a rounded proximal end and a distal end that is gradually reduced in cross-sectional area in the direction from the proximal end  40  toward the distal end  42 . In various examples, the plug  36  may have linear or curvilinear surfaces shaped to channel pressurized air (or a pressurized air/de-icing agent mixture) around the plug  36  through an annular opening  52  between the plug  36  and an inner surface of the sidewall  44 . In some examples, the plug  36  may be attached to an inner surface of the sidewall  44  by one or more struts  50 . In some examples, the one or more struts  50  extend from an outer surface of the plug  36  to an inner surface of the sidewall  44  in a radially outward direction. The plug  36 , along with the struts  50 , may be positioned at a distal end  42  of the nozzle  16  such that at least a portion of the plug  36  extends distally from a terminal end of the nozzle body  34 . A plurality of struts  50  may be provided with even or uneven spacing or angular extension between the struts  50  in a circumferential direction. In some examples, the one or more struts  50  may be substantially perpendicular to the longitudinal axis  46 , or angled at an obtuse or acute angle relative to the longitudinal axis  46  when viewed from a proximal end  40  toward the distal end  42 . 
         [0042]    With continued reference to  FIGS. 2A-2B , the cowl  38  has a first portion  54   a  and a second portion  54   b  extending distally from the first portion  54   a.  The first portion  54   a  may have a substantially cylindrical shape having an inner diameter that is at least slightly larger than an outer diameter of the nozzle body  34 . The second portion  54   b  has a substantially conical shape that gradually narrows in diameter in a direction from the proximal end  40  to the distal end  42 . The second portion  54   b  of the cowl  38  terminates in an open end  56 . In some examples, the cowl  38  is movably connected to the nozzle body  34 . The cowl  38  may be movable from a first position ( FIG. 2A ) to a second position ( FIG. 2B ) in a direction along the longitudinal axis  46 . In some examples, a drive mechanism  58 , such as an electric motor or a mechanical linkage, is provided for moving the cowl  38  relative to the nozzle body  34  in a direction along the longitudinal axis  46 . The drive mechanism  58  may be operatively connected to the controller  30  (shown in  FIG. 1 ) for controlling the position of the cowl  38  relative to the nozzle body  34 . The cowl  38  may be reciprocally movable relative to the nozzle body  34 . 
         [0043]    With reference to  FIGS. 2A-2B , an annular space  60  is defined between an inner surface of the second portion  54   b  of the cowl  38  and an outer surface of the distal end of the plug  36 . Movement of the cowl  38  relative to the nozzle body  34  controls the cross-sectional area of the annular space  60  between a first area ( FIG. 2A ) and a second area ( FIG. 2B ). In some examples, the cross-sectional area of the annular space  60  increases as the cowl  38  is moved from the proximal end  40  toward the distal end  42  relative to the nozzle body  34 . In a first configuration ( FIG. 2A ), the nozzle  16  is configured for delivering the pressurized air (or pressurized air/de-icing agent mixture) at a high pressure and low volume. In this manner, the nozzle  16  is configured for breaking adhesion between snow/ice and the surface of the aircraft  18  (shown in  FIG. 1 ). In a second configuration ( FIG. 2B ), the nozzle  16  is configured for delivering the pressurized air (or pressurized air/de-icing agent mixture) at a low pressure and high volume. In this manner, the nozzle  16  is configured for sweeping loose snow/ice from the surface of the aircraft  18  (shown in  FIG. 1 ) at greater distances. A seal  62  may be disposed between an inner surface of the cowl  38  and an outer surface of the nozzle body  34  to seal the interface between the inner surface of the cowl  38  and the outer surface of the nozzle body  34 . 
         [0044]    With reference to  FIGS. 3A-3B , the nozzle  16  is shown in accordance with another preferred and non-limiting example of the present invention. The components of the nozzle  16  shown in  FIGS. 3A-3B  are substantially similar or identical to the components of the nozzle  16  described herein with reference to  FIGS. 2A-2B . As the previous discussion regarding the nozzle  16 , generally shown in  FIGS. 2A-2B , is applicable to the example of the nozzle  16  shown in  FIGS. 3A-3B , only the relative differences between the nozzles  16  are discussed hereinafter. 
         [0045]    While the cowl  38  is movable relative to the nozzle body  34  in the nozzle  16  described herein with reference to  FIGS. 2A-2B , the cowl  38  in  FIGS. 3A-3B  is fixed (i.e., not movable) relative to the nozzle body  34 . In some examples, the cowl  38  may be removably or non-removably attached with the nozzle body  34 , such that the distal end  42  of the nozzle body  34  is directly or indirectly connected with the first portion  54   a  of the cowl  38 . The cowl  38  may be monolithically formed with the nozzle body  34 . In order to control the cross-sectional area of the annular space  60 , the plug  36  has a first portion  64   a  that is fixed relative to the nozzle body  34  and the cowl  38 , and a second portion  64   b  that is movable relative to the first portion  64   a,  and therefore also movable relative to the nozzle body  34  and the cowl  38 . The second portion  64   b  of the plug  36  may be movable relative to the first portion  64   a  from a first position ( FIG. 3A ) to a second position ( FIG. 3B ) in a direction along the longitudinal axis  46 . In some examples, a drive mechanism  66 , such as an electric motor or a mechanical linkage, is provided for moving the second portion  64   b  of the plug  36  relative to the first portion  64   a  in a direction along the longitudinal axis  46 . The drive mechanism  66  may be operatively connected to the controller  30  (shown in  FIG. 1 ) for controlling the position of the second portion  64   b  of the plug  36  relative to the first portion  64   a.  The second portion  64   b  of the plug  36  may be reciprocally movable relative to the first portion  64   a.    
         [0046]    With continued reference to  FIGS. 3A-3B , the annular space  60  is defined between an inner surface of the cowl  38  and an outer surface of the second portion  64   b  of the plug  36 . Movement of the second portion  64   b  of the plug  36  relative to the first portion  64   a  controls the cross-sectional area of the annular space  60  between a first area ( FIG. 3A ) and a second area ( FIG. 3B ). In some examples, the cross-sectional area of the annular space  60  increases as the second portion  64   b  of the plug  36  is moved from the proximal end  40  toward the distal end  42  relative to the first portion  64   a.  In a first configuration ( FIG. 3A ), the nozzle  16  is configured for delivering the pressurized air (or pressurized air/de-icing agent mixture) at a high pressure and low volume. In this manner, the nozzle  16  is configured for breaking adhesion between snow/ice and the surface of the aircraft  18  (shown in  FIG. 1 ). In a second configuration ( FIG. 3B ), the nozzle  16  is configured for delivering the pressurized air (or pressurized air/de-icing agent mixture) at a low pressure and high volume. In this manner, the nozzle  16  is configured for sweeping loose snow/ice from the surface of the aircraft  18  (shown in  FIG. 1 ) at greater distances. A seal  68  may be disposed between an inner surface of the second portion  64   b  of the plug  36  and an outer surface of the first portion  64   a  to seal the interface therebetween. 
         [0047]    With reference to  FIGS. 4A-4B , a nozzle  16   a  is shown in accordance with another preferred and non-limiting example of the present invention. The nozzle  16   a  has a nozzle body  34   a,  and a cowl  38   a  surrounding at least a portion of the nozzle body  34   a.  In some examples, the nozzle body  34   a  is formed as a cylindrical conduit having a proximal end  40   a  and a distal end  42   a  with a sidewall  44   a  extending therebetween along a longitudinal axis  46   a.  The distal end  42   a  of the nozzle body  34   a  may be conical such that it gradually tapers from the proximal end  40   a  toward the distal end  42   a.  Pressurized air from the pressurized air source  26  (shown in  FIG. 1 ) is delivered through the nozzle body  34   a  in a direction from the proximal end  40   a  toward the distal end  42   a,  as shown by the arrow A in  FIGS. 4A-4B . A fluid inlet  48   a  is configured to deliver the de-icing agent to the nozzle  16   a  for mixing with the pressurized air. In one example, the fluid inlet  48   a  may be at the proximal end  40   a  of the nozzle body  34   a  and extends through the sidewall  44   a  of the nozzle body  34   a.  In another example, the fluid inlet  48   a  may extend through the sidewall of the cowl  38   a.  In yet another example, the fluid inlet  48   a  may be external to the nozzle body  34   a  and the cowl  38   a.  In this example, the de-icing agent is delivered by gravity to a stream of pressurized air to become entrained with the stream, thereby forming a jet of pressurized air/de-icing fluid mixture. 
         [0048]    With continued reference to  FIGS. 4A-4B , the cowl  38   a  has a first portion  54   a ′ and a second portion  54   b ′ extending distally from the first portion  54   a ′. The first portion  54   a ′ may have a substantially conical shape that gradually narrows in diameter in a direction from the proximal end  40   a  to the distal end  42   a.  The first portion  54   a ′ may have an inner diameter that is at least slightly larger than an outer diameter of the distal end  42   a  nozzle body  34   a.  The second portion  54   b ′ has a substantially cylindrical shape that terminates in an open end  56   a.  In some examples, the cowl  38   a  is movable relative to the nozzle body  34   a.  One or more struts (not shown) may be provided between the cowl  38   a  and the nozzle body  34   a.  The cowl  38   a  may be movable from a first position ( FIG. 4A ) to a second position ( FIG. 4B ) in a direction along the longitudinal axis  46   a.  In some examples, a drive mechanism  58   a,  such as an electric motor or a mechanical linkage, is provided for moving the cowl  38   a  relative to the nozzle body  34   a  in a direction along the longitudinal axis  46   a.  The drive mechanism  58   a  may be operatively connected to the controller  30  (shown in  FIG. 1 ) for controlling the position of the cowl  38   a  relative to the nozzle body  34   a.  The cowl  38   a  may be reciprocally movable relative to the nozzle body  34   a.    
         [0049]    With continued reference to  FIGS. 4A-4B , an annular space  60   a  is defined between an inner surface of the cowl  38   a  and an outer surface of the distal end  42   a  of the nozzle body  34   a.  Movement of the cowl  38   a  relative to the nozzle body  34   a  controls the cross-sectional area of the annular space  60   a  between a first area ( FIG. 4A ) and a second area ( FIG. 4B ) to control an amount of the de-icing agent, pressurized air, and/or a mixture of the de-icing agent and the pressurized air from being introduced through the annular space  60   a  in a direction of arrow B. In some examples, the cross-sectional area of the annular space  60   a  increases as the cowl  38   a  is moved away from the nozzle body  34   a.  The cowl  38   a  may be movable relative to the nozzle body  34   a  axially in a direction of the longitudinal axis  46   a.  In some examples, the cowl  38   a  may be rotatable radially in a direction around the longitudinal axis  46   a  relative to the nozzle body  34   a.  In this example, the size of the annular space  60   a  may be controlled by a rotational position of the cowl  38   a  relative to the nozzle body  34   a.  For example, rotation of the cowl  38   a  in a first direction (such as clockwise) about the longitudinal axis  46   a  may increase (or decrease) the cross-sectional area of the annular space  60   a.  Conversely, rotation of the cowl  38   a  in a second direction opposite to the first direction (such as counter-clockwise) about the longitudinal axis  46   a  may decrease (or increase) the cross-sectional area of the annular space  60   a.    
         [0050]    In a first configuration ( FIG. 4A ), the nozzle  16   a  is configured for delivering the pressurized air (or pressurized air/de-icing agent mixture) at a low pressure and high volume. A first stream of pressurized air (or pressurized air/de-icing agent mixture) passing through the nozzle body  34   a  is mixed with a second stream of ambient air (or unpressurized air/de-icing agent mixture) drawn through the annular space  60   a  such that the first and second streams of pressurized air (or pressurized air/de-icing agent mixture) mix in a mixing region  68  of the cowl  38   a  distally from the distal end  42   a  of the nozzle body  34   a.  In this manner, the nozzle  16   a  is configured for sweeping loose snow/ice from the surface of the aircraft  18  (shown in  FIG. 1 ) at greater distances. In a second configuration ( FIG. 4B ), the nozzle  16   a  is configured for delivering the pressurized air (or pressurized air/de-icing agent mixture) at a high pressure and low volume. The cowl  38   a  may contact the nozzle body  34   a  such that no pressurized air (or pressurized air/de-icing agent mixture) enters through the annular space  60   a.  In this manner, the nozzle  16   a  is configured for breaking adhesion between snow/ice and the surface of the aircraft  18  (shown in  FIG. 1 ). 
         [0051]    In various examples, the fluid delivery to the nozzle  16  and configuration of the nozzle  16  between the high pressure, low volume mode and the low pressure, high volume mode may be synchronized so that a predetermined supply of pressurized air and/or de-icing fluid is delivered to the nozzle  16  depending on the configuration of the nozzle  16 . Such synchronization of the air and/or fluid supply to the nozzle  16  contributes to the formation of a desired jet stream, such as a high pressure, low volume jet stream in the high pressure, low volume mode of the nozzle  16  operation, a low pressure, high volume jet stream in the low pressure, high volume mode of the nozzle  16  operation, or any intermediate configuration of the nozzle  16  between these two modes. In some examples, the volume of the pressurized air delivered to the nozzle  16  from the pressurized air source  26  and/or the volume of the de-icing agent delivered to the nozzle  16  by the pump  22  may be adjusted to correspond to air and/or fluid requirements of the nozzle  16  based on its operating mode. For example, if the configuration of the nozzle  16  is adjusted to the high pressure, low volume mode, the pressurized air and/or de-icing agent delivered to the nozzle  16  are adjusted accordingly by reducing the volume of air and/or fluid supplied to the nozzle  16 . Such reduction in supply of air and/or fluid may be effected by reducing the supply from the pressurized air source  26  and/or the pump  22 . Similarly, if the configuration of the nozzle  16  is adjusted to the low pressure, high volume mode, the pressurized air and/or de-icing agent delivered to the nozzle  16  are adjusted accordingly by increasing the volume of air and/or fluid supplied to the nozzle  16 . Such increase in supply of air and/or fluid may be effected by increasing the supply from the pressurized air source  26  and/or the pump  22 . Synchronized operation of the nozzle  16 , pump  22 , and pressurized air supply  26  may be controlled by the controller  30  to ensure the optimal air/fluid supply to the nozzle  16  based on a desired jet stream configuration. In some examples, the pressurized air and de-icing fluid delivered to the nozzle  16  and the configuration of the nozzle  16  may be adjusted manually to address special weather conditions and situations and allow for an increased number of combinations of selections. 
         [0052]    With reference to  FIG. 5 , this figure represents a jet velocity of a pressurized air/de-icing agent mixture downstream of the nozzle  16  as a function of distance away from the nozzle exit. Three different nozzle configurations are illustrated as Lines A, B, and C. Line A represents jet velocity when nozzle  16  is operated in a high pressure, low volume mode. The jet velocity drops significantly as the distance increases away from the nozzle exit. Line B represents a low pressure, low volume delivery typically associated with conventional nozzles when operated with Type IV fluids. The shape of Line B is roughly equivalent to the shape of Line A, although the velocity of the jet stream is substantially lower. Line C represents a jet stream velocity as a function of distance when the nozzle  16  is operated in a low pressure, high volume mode. It can be seen from the graph in  FIG. 5 , Line C that the jet stream velocity stays substantially constant at a distance between 12″ to 26″ away from the nozzle exit. At distances greater than 36″, the jet stream velocity of Line C decays at a lower rate than for Lines A and B. Moreover, the jet velocity is substantially higher at distances greater that 36″ than the jet velocity for Lines A and B. It can be seen that the low pressure, high volume mode sustains higher jet velocity over a longer distance from the nozzle  16  exit. The low initial velocity in Line C is advantageous for the use of Type IV fluid. 
         [0053]    Although the disclosure has been described in detail for the purpose of illustration based on what are currently considered to be the most practical and preferred examples, it is to be understood that such detail is solely for that purpose and that the disclosure is not limited to the disclosed examples, but, on the contrary, is intended to cover modifications and equivalent arrangements. For example, it is to be understood that the present disclosure contemplates that, to the extent possible, one or more features of any example can be combined with one or more features of any other example.