Abstract:
The present invention relates to the field of washing engines, particularly using washing liquids such as water and detergent or water only, and more specifically to systems, apparatus and a mobile cart comprising such a system for collecting and treating the waste water from engine washing operations. The system comprises a collecting device for collecting waste liquid during a washing operation of the engine and a treatment device for treating waste liquid collected during said washing operation. According to an embodiment, the system is arranged on a mobile cart ( 50 ) for serving an engine ( 1 ) during a washing operation of the engine ( 1 ) comprising a chassis provided with wheels. The mobile cart also includes adjusting means ( 73 ) for adjusting the vertical position of the liquid separating means ( 31 ) and/or adjusting means for adjusting the vertical position of the liquid collecting means ( 302, 36 ) relative the engine ( 1 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention generally relates to the field of washing jet engines, particularly using washing liquids such as water and detergent or water only, and more specifically to a system, and devices for collecting and treating the waste water from engine washing operations and a mobile cart comprising such a system. 
       BACKGROUND OF THE INVENTION 
       [0002]    A gas turbine engine installed as an aircraft engine comprises a compressor compressing ambient air, a combustor burning fuel together with the compressed air and a turbine for driving the compressor. The expanding combustion gases drive the turbine and also result in thrust used for propelling the aircraft. 
         [0003]    Air breathing machines like Jet engines consume large quantities of air. Air contains foreign particles in form of aerosols or larger particles which then enters the engine with the air stream. The majority of the particles will follow the gas path through the engine and exit with the exhaust gases. However, there are particles with properties of sticking on to components in the engine&#39;s gas path changing the aerodynamic properties of the engine and more particularly reducing engine performance. Typical contaminants found in the aviation environment are pollen, insects, engine exhaust, leaking engine oil, hydrocarbons coming from industrial activities, salt coming from nearby sea, chemicals coming from aircraft de-icing and airport ground material such as dust. 
         [0004]    The contaminants sticking on to components in the engine gas path cause fouling of the engine. The consequence of gas path fouling is an engine operating less efficient. With the reduction in efficiency follows that the engine is less economic to operate and has higher emissions. Fouling will result in more fuel having to be burnt for achieving the same thrust as for the clean engine. Further, an environmental drawback is found with the higher fuel consumption in form of increased carbon dioxide emissions. In addition, more fuel being burnt results in higher temperatures in the engine&#39;s combustor. With this follows high temperature exposure to engine hot section components. The higher temperature exposures will shorten the life time of the engine. The higher firing temperature results in increased formation of NOx which is yet another environmental drawback. In summary, the operator of a fouled engine suffers from reduced engine lifetime, unfavourable operating economics and higher emissions. The airline operators have therefore a strong incentive keeping the engine clean. 
         [0005]    It has been found that the only reasonable way to combat fouling is to wash the engine. Washing can be practiced by directing a water jet from a garden hose towards the engine inlet. However, this method has limited success due to the simple nature of the process. An alternative method is pumping the wash liquid through a manifold with special nozzles directed towards the engine inlet face. The manifold would be temporarily installed on the engine cowl or on the engine shaft bullet during the wash operation. Simultaneously with spraying the washing liquid towards the engine inlet, the engine shaft is cranked by the use of its starter motor. The shaft rotation enhances the wash result by the mechanical movements. The shaft rotation allows the wash liquid to move over greater surface area as well as enhancing liquid penetration into the interior of the engine. The method is proven successful on most gas turbine jet engines types such as turbojets, turboprop, turboshaft and mixed or un-mixed turbofan engines. 
         [0006]    A proper wash operation of a gas turbine engine can be confirmed by an observation that the wash liquid exits the engine at the engine outlet. At the engine outlet the wash liquid has become a waste liquid. The waste liquid may leave the engine outlet as a stream of liquid pouring to the ground. Alternatively may the waste liquid be carried with the air stream as fine droplets where the air stream is the result of the rotation of the engine shaft. This air borne liquid can be carried a significant distance before falling to the ground. It is shown from actual wash operations that waste liquid will be spread on a large surface area, typically more than 20 meters downstream of the engine outlet. It is not desired to spread waste liquid on the ground. It is the purpose of this invention to provide a method and apparatus to collect the waste liquid exiting the engine. 
         [0007]    The waste liquid exiting the engine at washing consists of the wash liquid entering the engine together with released fouling material, combustion solids, compressor and turbine coating material, and oil and fat products. This waste liquid may be hazardous. As an example, analysis of water collected from actual turbine engine washing operations showed to contain cadmium. The cadmium comes from compressor blade coating material released during washing operation. Cadmium is environmentally very sensitive and can not be allowed to be disposed to the effluent. This waste liquid would have to undergo treatment for separation of hazardous components before being disposed in a sewer. 
         [0008]    Gas turbine aircraft engines can be of different types such as turbojets, turboprop, turbo-shaft and mixed or un-mixed turbofan engines. These engines cover a large performance range and may comprise of different design details by different manufactures. Aircrafts types for a defined service may be offered from different aircraft manufacturers thus the design of the aircraft and its engines may vary. Further, the aircraft manufacturer may offer different engine options for the same aircraft type. The large combined possibility of engines on aircraft types and from different aircraft manufacturers result in a practical problem in designing a system for collecting and treating of waste wash liquid that is generally applicable to most winged aircraft. U.S. Pat. No. 5,899,217 to Testman, Jr. discloses an engine wash recovery system that is limited to small and particularly turboprop engines as the container used in the invention is not applicable to the air flows emanating from e.g. large turbo-fan engines. 
         [0009]    Collecting waste water from engine washing may be accomplished by hanging canvas like collectors under the engine nacelle. However, any operation resulting in anything being hooked on to an engine has the disadvantage that it may be subject to engine damage 
       SUMMARY OF THE INVENTION 
       [0010]    Thus, it is an object of this invention to provide a method and apparatus enabling collecting and treating waste water from engine washing for a large range of aircraft types including the largest aircraft types. 
         [0011]    It is a further object of the present invention to provide a method and apparatus for removing hazardous components from the waste water before disposing it. 
         [0012]    It is an additional object of the present invention to provide a method and apparatus for collecting and treating waste water from engine washing having no physical contact between the collector device and engine. 
         [0013]    It is yet another object of the present invention to provide a method and apparatus for enabling clean engine operations. 
         [0014]    These and other objects are achieved according to the present invention by providing devices and systems having the features defined in the independent claims. Preferred embodiments are defined in the dependent claims. 
         [0015]    According to a first aspect of the present invention, there is provided a system for collecting and treating waste liquid from engine washing. The system comprises a collecting device for collecting waste liquid during a washing operation of an engine, wherein the collecting device comprises liquid separating means having an inlet face and an outlet face arranged to separate washing liquids from the air stream entering the inlet face, which air stream emanates from the engine during the washing operating of the engine; and liquid collecting means for collecting separated liquid from liquid separating means and liquid exiting the engine resulting from the washing operation. Furthermore, the system comprises a treatment device for treating waste liquid collected during the washing operation, wherein the treatment device comprises filter means arranged to remove particles and ions from the liquid, wherein the treatment device is connected to the collecting device such that waste liquid is directed from the liquid collecting means to the treatment device for treatment in the filter means. 
         [0016]    According to a second aspect of the present invention, there is provided a collecting device for collecting waste liquid during a washing operation of an engine, wherein the collecting device comprises liquid separating means having an inlet face and an outlet face arranged to separate washing liquids from the air stream entering the inlet face, which air stream emanates from the engine during the washing operating of the engine; and liquid collecting means for collecting separated liquid from liquid separating means and liquid exiting the engine resulting from the washing operation. 
         [0017]    According to a third aspect of the present invention, there is provided a treatment device for treating waste liquid collected during a washing operation, wherein the treatment device comprises filter means arranged to remove particles and ions from the liquid. 
         [0018]    According to a further aspect of the present invention, there is provided a mobile cart for serving a engine during a washing operation of the engine comprising a chassis provided with wheels. The cart comprises a system according to the first aspect of the present invention arranged on the chassis; adjusting means for adjusting the position of the liquid separating means and/or liquid collecting means and/or the liquid storage means relative the engine. 
         [0019]    The solution according to the present invention provides several advantages over the existing solutions. One advantage is that hazardous particles, substances, or other types of content, such as released fouling material, combustion solids, compressor and turbine coating material, heavy metals and oil and fat products, can be removed or separated from the waste liquid resulting from a washing operation in an efficient and environmentally friendly manner 
         [0020]    Another advantage is the inventive devices and systems can be used with different types and designs of gas turbine aircraft engines, such as turbojets, turboprop, turbo-shaft and mixed or un-mixed turbofan engines, and, moreover, with different aircraft types and designs from different manufactures because the devices and systems can be accurately adjusted to a specific engine or aircraft. Accordingly, the present invention provides for a very high degree of flexibility since one system can be used for all types of engines and aircrafts, i.e. the present invention provides for a collecting and treating of waste wash liquid generally applicable to most winged aircraft. This also entails cost savings because one and the same system or mobile cart including the system can be used for all types of engines and aircrafts. 
         [0021]    A further advantage is that there is no physical contact between the collector device and the engine, which entails that any damages of the engines can be avoided. 
         [0022]    Further objects and advantages of the present invention will be discussed below by means exemplifying embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    Preferred embodiments of the invention will now be described in greater detail with reference to the accompanying drawings, in which 
           [0024]      FIG. 1  shows a cross section of an un-mixed turbo-fan gas turbine engine. 
           [0025]      FIG. 2  shows how waste liquid may exit the un-mixed turbo-fan engine during washing thereof. 
           [0026]      FIG. 3  shows the waste liquid collecting device according to the invention. 
           [0027]      FIG. 4   a  shows a waste liquid treatment process prior to disposal in a sewer. 
           [0028]      FIG. 4   b  shows an alternative waste liquid treatment process prior to disposal in a sewer. 
           [0029]      FIG. 5  shows the waste liquid collecting device and treatment device installed on a mobile cart for practical use in servicing aircraft at airports. 
           [0030]      FIG. 6  shows the mobile cart with the waste water collecting device and treatment device positioned for service of an under-wing mounted engine. 
           [0031]      FIG. 7  shows the mobile cart with the waste water collecting device and treatment device positioned for service of a tail mounted engine. 
           [0032]      FIG. 8  shows an embodiment of the separator profiles of the droplet separator shown in  FIG. 3 . 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0033]    The invention can be practised on several engine types such as turboshaft, turboprop, turbojet and mixed/un-mixed multi shaft turbo fan engines. The invention can be practised on under-wing mounted engines as well as tall mounted engines as further shown in  FIG. 6  and  FIG. 7 . 
         [0034]      FIG. 1  shows a cross section of an un-mixed turbofan engine. This engine is of a common type found on e.g. large aircraft in passenger service. Engine  1  comprises of a fan section  102  and a core engine section  103 . Air flows are indicated by arrows. Engine  1  has an inlet  10  where air enters the engine. The air flow is driven by fan  15 . One portion of the inlet air exits at outlet  11 . The remaining portion of the inlet air enters into the core engine at inlet  13 . The air to the core engine is compressed by compressor  17 . The compressed air together with fuel (not shown) is combusted in combustor  101  resulting in pressurized hot combustion gases. The pressurized hot combustion gases expand towards core engine outlet  12 . The expansion is done in two stages. In a first stage the combustion gases expand into an intermediate pressure while driving turbine  18 . In a second stage the combustion gases expand towards ambient pressure while driving turbine  16 . Turbine  16  is driving fan  15  via shaft  14 . Turbine  18  is driving compressor  17  via a second shaft  19  where the second shaft  19  is in form of a coaxial to first shaft  14 . 
         [0035]    In  FIG. 2  the engine described in  FIG. 1  is subject to an engine wash. Similar parts are shown with the same reference numbers as  FIG. 1 .  FIG. 2 . shows a side view of engine  1 . Engine  1  is an “under-wing engine” installed under wing  21  with support  22  where wing  21  is part of aircraft  2 . A manifold (not shown) for injecting washing liquid is installed in the engine inlet  10  of engine  1 . The manifold holds a plurality of nozzles  24  in position upstream of the fan. A wash pump unit (not shown) pumps a washing liquid through nozzles  24  forming sprays  25  directed toward the fan and core engine air inlets. The liquid cleans the gas paths of the fan and the core engine. To enhance the cleaning effect the engine shafts are cranked by the use of the engine&#39;s starter motor. Cranking of the shafts enables the liquid to move around inside the engine for achieving enhanced cleaning effect. The rotation of the shafts results in an airflow carrying the liquid towards the engine outlet hence liquid will exit the engine at the rear. Liquid exiting the engine is waste liquid. 
         [0036]    Liquid will exit the engine in at least five different ways as described in  FIG. 2 . The first liquid category, stream  201 , will exit the core engine outlet  12  as airborne droplets. The droplets that make up stream  201  are generated inside the engine by the motion of the compressor and turbines blades. Stream  201  comprises of droplets with a large size range where the different droplet sizes have different characteristics. The smallest droplets, i.e. droplets less than 30 microns will typically quickly evaporate in the ambient air as of their small size. Droplets less than 30 microns are therefore not so much of concern in the waste water collection process for reason of the evaporation and that they represent only a small volume of the waste liquid. The largest droplets in stream  201  are droplets in the size of raindrops, e.g. 2000 um size. These droplets are heavy and will not evaporate but fall to the ground by gravity. Droplets greater than 30 microns but less than 2000 microns will be carried with the air stream and fall by gravity to ground  23  typically up to 20 meters behind the engine outlet. The second liquid category, stream  202 , consists of strings of liquid and other large chunks of liquid. Stream  202  quickly falls to the ground  23  by gravity. The third liquid category, stream  203 , is liquid pouring as a solid stream out of the core engine outlet  12 . This liquid pours typically vertically to ground  23 . The fourth liquid category, stream  204 , is liquid pouring out from the fan duct outlet  11 . This liquid falls basically vertically to ground  23 . The fifth liquid category, stream  205 , is liquid dropping or pouring from the bottom of the engine nacelle. The source for this liquid is for example the combustor drain valves being open. According to the invention a method and apparatus is disclosed for collecting waste liquid exiting the engine as described in  FIG. 2 . 
         [0037]      FIG. 3  show a side view of engine  1  and how waste liquid is collected during washing according to the invention. Similar parts are shown with the same reference numbers as  FIG. 2 . Collector  3  consist of a droplet separator  31 , a trough  36  and a chute  302 . Liquid exiting the engine as stream  201  is separated from the carrier air in droplet separator  31 . Liquid exiting the engine as stream  202 , stream  203 , stream  204  and stream  205  are collected by chute  302 . The liquid emanating from droplet separator  31  and chute  302  is collected in trough  36 . 
         [0038]    Droplet separator  31  consists of a frame enclosing droplet separator profiles. Droplet separator  31  has an inlet face  32  directed towards air stream  201  and an outlet face  33  opposite to inlet face  32 . Stream  201  enters the droplet separator at inlet face  32  and exits the droplet separator at outlet face  33 . The liquid is trapped in separator  31  so that stream  301  is essentially free from liquid after passing through droplet separator  31 . Droplet separator  31  consists of vertically arranged separator profiles (see  FIG. 8 ) in a frame. The separator profiles deflect the air stream. As a result the momentum of the droplets causes them to impinge onto the profile surface. The droplets coalesce together and form a liquid film. The influence of gravity on the film causes the liquid to drain to the bottom of the profile and exit the droplet separator at face  34  as stream  35 . Waste liquid stream  35  falls by gravity into trough  36 . 
         [0039]    Droplet separator  31  consists of a frame enclosing droplet separator profiles.  FIG. 8  show the technique for separating air borne droplets with the use of separator profiles. The direction of the air stream is shown by arrows. The droplet separator profiles are arranged in parallel allowing for an air flow through the separator. The droplet separator profiles are arranged standing vertical allowing for liquid on the profile surface to find its way downwards by gravity.  FIG. 8  shows a cross section of three droplet separator profiles looking from above and downwards. Droplet separator profile  81  is shaped as shown in  FIG. 8 . At about the middle distance from the leading edge to the tall edge of the profile, a liquid trap  82  is formed as a pocket for collecting liquid on the surface of profile  81 . Droplets  84  are carried with the air stream in between the droplet separator profiles. Inside the separator the air is deflected as the result of the geometry of profile  81 . The air flow deflection is rapid enough to not allow the droplets to follow with the air. The inertia of droplets  84  then allows the droplets to travel un-deflected and impinge on profile  81  at point  83 . As liquid continues to build up on the profile surface a liquid film  85  is formed where the air stream shear forces will carry liquid  85  into liquid trap  82 . In liquid trap  82  the liquid will build up and pour downwards by gravity. 
         [0040]      FIG. 3  shows chute  302  installed under engine  1 . Chute  302  will collect liquid  202 ,  203 ,  204  and  205  as shown in  FIG. 3 . Chute  302  has a front end  39  and a rear end  38  where front end  39  is positioned vertically higher than rear end  38 . As front end  39  is higher than rear end  38 , the chute is inclined. The inclination of chute  302  will allow liquid in the chute to flow from the left to the right in  FIG. 3 . Rear end  38  is positioned above trough  36  so that liquid will pour out of chute  302  into trough  36  as stream  37 . According to an alternative embodiment, chute  302  is incorporated in trough  36  and tank  302 , thereby forming one single unit. 
         [0041]    The liquid that exits the engine during washing contain water, detergent and foreign matter. The foreign matter is in form of solids and ions dissolved in the water. What comes out of the engine at a specific wash occasion depends on a number of issues such as when washing was last conducted, the environment in which the engines operates, etc. Further, the waste liquid may at one wash occasion contain a high amount of solids while at another wash occasion be low on solids. Similarly, the waste liquid may at one wash occasion contain a high amount of ions while at another wash occasion be low on ions. This results in that the waste water treatment system must be flexible in its design so that the most appropriate treatment can be conducted at each occasion. The waste water treatment system described in  FIG. 4   a  shows the components and processing according to one treatment scheme.  FIG. 4   b  shows the same components yet a different treatment scheme. The scheme in  FIG. 4   a  and  FIG. 4   b  are example of two possible schemes where anyone skilled in the art can design additional schemes and yet remain within the objectives of the invention. 
         [0042]    There may be wash occasions where the waste water is non-hazardous. In such a case processing for removal of hazardous components would be unnecessary. The non-hazardous waste liquid may then be directly disposed off into a sewer. To enable the operator of the unit to decide if the waste water should undergo further treatment before disposal or to be disposed off directly, the operator may conduct a test. A possible test for this purpose is to measure the water electric conductivity. This test allows for an on-the-spot decision for direct disposal to a sewer or allow for further processing of the waste water. A small portable and battery powered conductivity meter may be used. According to this embodiment, the test procedure would then include sticking the measurement probe into the waste water and record the conductivity reading. The recorded values would then be compared to a table of acceptable and not acceptable values representing experience gained from laboratory analysis of waste waters from engine washings. The use of a conductivity meter for measuring the electric conductivity is an example only. Depending on the engine type and the environment in which the engine operates the operator may find alternative test methods to be more appropriate. 
         [0043]    In  FIG. 4   a , a trough  36  collects the waste liquid streams as stream  401 . From an opening at the bottom of trough  36  the waste liquid enters tank  303 . The waste liquid in tank  303  is allowed to settle for some time, typically less than 30 minutes. Particles that have a higher density than water will sediment to bottom  406  of tank  303 . Particles that typically will sediment to the bottom are fuel solid residues, coked hydrocarbons, compressor fouling material, and alike. Particles with less density than water will float to surface  407  of the waste liquid. Particles that typically will float to the surface are oils, fats, pollen, insect residues, residues from bird strikes and alike. In between the bottom sediment and the surface materials the waste liquid may contain metal ions and very small particles that will not sediment to the bottom or float to the surface. 
         [0044]      FIG. 4   a  shows the processing of the non-sediment waste liquid into a non-hazardous liquid. Outlet  408  of tank  303  allow waste water to exit in conduit  42 . Pump  43  pumps the liquid in conduit  42  to conduit  41 . The liquid will then continue to filter  47 . Filter  47  is a sediment type filter of a commercially available type. This filter will separate coarse and very fine particles. After filtration in filter  47  the liquid continues in conduit  48  to filter  49 . Filter  49  is a filter for separation of metal ions. Filter  49  can be a filter consisting of bed of metal particulate material matter. The metal particulate matter is chosen from metals having favourable redox potentials relative the redox potential of the waste water metal ions to establish conditions for spontaneous oxidation and reduction reactions with the metal ions. The metal particulate type filter is described in U.S. Pat. No. 4,642,192. After filtration in filter  47  and filter  49  the waste liquid is now depleted from particles and metal ions. The waste liquid continues in conduit  403  for disposal in a sewer or to a tank (not shown) for later disposal in a sewer. 
         [0045]    Tank  303  is open at the top. After tank  303  has been drained from waste liquid, the material floating on the waste liquid surface together with the settled material at bottom  406  of tank  303  can be manually collected by wiping it out with a cloth or similar operation. This material is then allowed to be disposed off in a safe way. 
         [0046]    If the liquid is non-hazardous it is not necessary with the processing as described above. The non-hazardous liquid may be disposed off into a sewer by opening valve  409 . 
         [0047]    The scheme in  FIG. 4   a  is appropriate for processing waste liquids having a high amount of solids. Tank  303  is then used as setting tank for solids and thus relieving the load on sediment filter  47 .  FIG. 4   b  shows an alternative scheme to the scheme in  FIG. 4   a . In  FIG. 4   b  a tank  303  is used as storage tank for storing waste liquid post processing. The scheme in  FIG. 4   b  is appropriate for processing waste liquid with low or moderate solids content. In  FIG. 4   b  similar parts are shown with the same reference numbers as  FIG. 3  and  FIG. 4   a . Waste liquid leaving trough  36  as stream  304  is pumped by pump  43  in conduit  42 . The liquid leaves pump  43  in conduit  41 . After similar processing in filter  47  and filter  49  as shown in  FIG. 4   a , the liquid continues in conduit  403  to tank  303 . The liquid entering tank  303  is now depleted from particulates and ions. Tank  303  will in this embodiment serve as a storage tank until it is appropriate to release its content into a sewer. The liquid is disposed into a sewer by opening valve  409 . 
         [0048]    The post processing or treatment method and device and the collection method and collection device according to the present invention can be used independently of each other. 
         [0049]      FIG. 5  shows the collection device and the water treatment unit installed on a mobile cart. The installation of collector  3  together with the waste water treatment unit on cart  50  allows the invention to become practical in servicing aircraft engines at airports. As one engine is being washed the unit collects and treats the waste water. After completion of the engine wash the cart is moved to the next engine of the aircraft, and so on. The installation on cart  50  as shown in  FIG. 5  is an example only. Anyone skilled in the art can design the cart differently and yet remain within the objectives of the invention. Similar parts are shown with the same reference numbers as  FIG. 2 ,  FIG. 3  and  FIG. 4 . 
         [0050]    Cart  50  comprises of a frame  51 . Frame  51  rests on a chassis (not shown for clarity) equipped with wheels  52 . Droplet separator  31  is supported by supports  53  installed on frame  51 . Chute  302 , trough (not shown for clarity), tank  303 , pump  43 , filter  47  and filter  49  are installed on frame  51 . According to this embodiment tank  303  has a volume of 500 litres. A screen  55  on each left and right side of the cart prevents air borne waste liquid to escape to the sides. A handle  56  allows the cart to be hand pulled or pulled by a vehicle. 
         [0051]      FIG. 6  shows cart  50  according to the invention positioned for operation of an under-wing installed engine  1 . As can be seen there is no physical contact between cart  50  and the aircraft. Droplet separator  31  is adjustable in height as indicated by arrows by means of adjusting means, which, for example, can be a hydraulic, pneumatic or chain driven unit. The adjustment in height of droplet separator  31  enables the cart to be positioned under the wing of the aircraft. The adjustment in height of droplet separator  31  enables the cart to be used for different aircraft types from different aircraft manufacturers and with different engines. According to an embodiment, the position of the droplet separator  31  can be adjusted relative the engine  1  in a vertical, horizontal, or lateral direction. 
         [0052]      FIG. 7  shows the cart  50  equipped with a scissor lift  73  for lifting frame  51  into position for collecting waste water from washing of a tail mounted engine  71 . According to an embodiment, the position of the frame  51  can be adjusted relative the engine  71  in a vertical, horizontal, or lateral direction. The cart  50  may also comprise a motor for driving the adjusting means for the droplet separator  31  and the scissor lift  73 . There is no physical contact between cart  50  and the aircraft. The use of the scissor lift  73  enables the cart to be used for different aircraft types from different aircraft manufacturers and with different engines. 
         [0053]    Although specific embodiments have been shown and described herein for purposes of illustration and exemplification, it is understood by those of ordinary skill in the art that the specific embodiments shown and described may be substituted for a wide variety of alternative and/or equivalent implementations without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Consequently, the present invention is defined by the wordings of the appended claims and equivalents thereof.