Abstract:
Turbines and associated equipment are normally cleaned via water or chemical pressure washing via a mist, spray systems. However, these systems fail to reach deep across the gas path to remove fouling materials. Various embodiments herein pertain to apparatus and methods that utilize the water and existing chemicals to generate a foam. The foam can be introduced at that gas-path entrance of the equipment, where it contacts the stages and internal surfaces, to contact, scrub, carry, and remove fouling away from equipment to restore performance. Various embodiments pertain to spout assemblies for providing foam to the compressor of commercial fan engines, and in yet other embodiments to engines receiving air from a long inlet duct, especially those having a serpentine inlet ducts.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 62/098,664, filed Dec. 31, 2015, incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Various embodiments of the present invention pertain to apparatus and methods for cleaning a gas path, especially a gas path including a combustion chamber, and in particular to apparatus and methods for cleaning of a gas turbine engine. 
       BACKGROUND 
       [0003]    Turbine engines extract energy to supply power across a wide range of platforms. Energy can range from steam to fuel combustion. Extracted power is then utilized for electricity, propulsion, or general power. Turbines work by turning the flow of fluids and gases into usable energy to power helicopters, airplanes, tanks, power plants, ships, specialty vehicles, cities, etc. Upon use, the gas-path of such devices becomes fouled with debris and contaminants such as minerals, sand, dust, soot, carbon, etc. When fouled, the performance of the equipment deteriorates, requiring maintenance and cleaning. 
         [0004]    It is well known that turbines come in many forms such as jet engines, industrial turbines, or ground-based and ship-based aero-derived units. The internal surfaces of the equipment, such as that of an airplane or helicopter engine, accumulate fouling material, deteriorating airflow across the engine, and diminishing performance. Correlated to this trend, fuel consumption increases, engine life shortens, and power available decreases. The simplest means and most cost effective means to maintain engine health and restore performance are to properly clean an engine. There are many methods available, such as mist, sprays, and vapor systems. However, all fail to reach deep or across the entire engine gas-path. Further, telemetry or diagnostic tools on engine have become routine functions to monitor engine health. Yet, using such tools to monitor, trigger, or quantify improvement from foam engine cleaning need to be utilized. Various embodiments of the present invention provide novel and unobvious methods and apparatus for the injecting chemical cleaning agents into of such power plants. 
       SUMMARY OF THE INVENTION 
       [0005]    In one embodiment, foam material is introduced at the gas-path entry of turbine equipment while off-line. The foam coats and contacts the internal surfaces, scrubbing, removing, and carrying fouling material away from equipment. The effluent is collected for post processing and various other embodiments of the present invention apply the use of diagnostic tools to enhance the utility of the present invention. 
         [0006]    One aspect of the present invention pertain to a system for providing an air-foamed liquid cleaning agent. Some embodiments include an air pump providing air at pressure higher than ambient pressure, and a liquid pump providing the liquid cleaner at pressure. Yet other embodiments include a nucleation device receiving air from the air pump, and liquid from the liquid pump, and creating a foam having a structure. Still other embodiments include a spout assembly in an approximate J-shape and including a foam inlet linearly spaced apart from a hooked end having a foam exit the nozzle being adapted and configured to deliver a stream of foam at a velocity of less than about twenty feet per second. 
         [0007]    Another aspect of the present invention pertains to a method for providing an air-foamed water soluble liquid cleaning agent to a jet engine having a bypass duct. Some embodiments include providing a source of liquid cleaning agent, a turbulent mixing chamber, and a spout assembly having a non-atomizing delivery nozzle. Yet other embodiments include mixing air with liquid in the mixing chamber and creating a supply of foam. 
         [0008]    Yet further aspects of the present invention pertain to a method for providing a foamed liquid cleaning agent to a jet engine receiving air from a serpentine inlet duct. Such ducts have become common on some military aircraft in order to prevent line of site viewing of the engine front face. Some such ducts include bends in a lateral direction (such as inboard) as well as a vertical direction (upward) to provide air to a buried engine. Some embodiments include spout assemblies adapted and configured with a receptacle on the distalmost end of the spout assembly that positively locates the distalmost end on a specific feature of the engine, inlet, or aircraft. Having such a receptacle, a subsequent coupling of that receptacle to an engine feature permits maintenance personnel to have positive verification that the spout assembly is correctly located in the duct. 
         [0009]    It will be appreciated that the various apparatus and methods described in this summary section, as well as elsewhere in this application, can be expressed as a large number of different combinations and subcombinations. All such useful, novel, and inventive combinations and subcombinations are contemplated herein, it being recognized that the explicit expression of each of these combinations is unnecessary. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Some of the figures shown herein may include dimensions. Further, some of the figures shown herein may have been created from scaled drawings or from photographs that are scalable. It is understood that such dimensions, or the relative scaling within a figure, are by way of example, and not to be construed as limiting. 
           [0011]      FIG. 1A  is a graphical representation of a section view of a large aircraft engine being cleaned with a system according to one embodiment of the present invention. 
           [0012]      FIG. 1B  is a schematic representation of a foam delivery system according to one embodiment of the present invention. 
           [0013]      FIG. 2A  is a graphical representation of the spout placement as represented on the cross-section view of a large aircraft engine. 
           [0014]      FIG. 2B  is a close up view a graphical representation of the spout placement to inject cleaning product as desired into the compressor section of the aircraft engine. 
           [0015]      FIG. 2C  is a graphical perspective angle-view of a side-cross-section and front view of and aircraft engine of  FIG. 2A . 
           [0016]      FIG. 3A  is in similar perspective to  FIG. 2C  but with the fan section and inlet cone removed. 
           [0017]      FIG. 3B  is a graphical representation of the spout fastened to engine structural struts. 
           [0018]      FIG. 4  is a drawing of multiple embodiments V. 1 , V. 2 , and V. 3  of inventive apparatus. 
           [0019]      FIG. 5  is a drawing of a nozzle according to one embodiment of the present invention. 
           [0020]      FIG. 6A  is a photographic representation of one embodiment of the present invention attached to a Pratt &amp; Whitney 4098 model engine. 
           [0021]      FIG. 6B —Left is a photographic representation of the apparatus of  FIG. 6A  showing the spout assembly entering through the rear of the air bypass section to the left of the engine (as viewed from the front), and between the fan and compressor section of the engine. 
           [0022]      FIG. 6B —Right is a photographic representation similar to  FIG. 6B -Left, and showing the spout assembly placed through the fan exit vanes on the right side of the engine. The spout is coupled to the fan vanes to prevent movement. 
           [0023]      FIG. 6C  is a photographic representation showing placement of the apparatus of  FIG. 6A  as seen from the front of the engine, and above the centerline of the engine. 
           [0024]      FIG. 6D  is a close up photographic representation of the apparatus of  FIG. 6A  as seen from the front of the engine, and with the apparatus placed at about the same elevation as the centerline of the engine. 
           [0025]      FIG. 6E  is a close up photographic representation of the apparatus of  FIG. 6C ; the spout is placed to provide foam between compressor inlet guide vanes and to the compressor inlet. 
           [0026]      FIG. 7  is a photographic representation, including a marked yardstick, and showing some relative dimensions of the apparatus of  FIG. 6A . 
           [0027]      FIG. 8A  is a photographic representation of the apparatus of  FIG. 6A  placed into a General Electric CF34 engine installed on an aircraft. 
           [0028]      FIG. 8B  is a photographic representation similar to  FIG. 8A  from the rear of engine. 
           [0029]      FIG. 8C  is a close-up photographic representation of a portion of the apparatus of  FIG. 8B . 
           [0030]      FIG. 9  is a schematic representation of a system according to one embodiment of the present invention. 
           [0031]      FIG. 10A  is a graphical representation from an engine inlet looking aft, and showing the forward-facing surface of a spout assembly according to one embodiment of the present invention. 
           [0032]      FIG. 10B  is a graphical representation from an engine inlet looking aft, and showing the forward-facing surface of a spout assembly according to yet another embodiment of the present invention. 
           [0033]      FIG. 11A  is a top plan form view of an aircraft with buried engines, and showing a spout assembly according to one embodiment of the present invention. 
           [0034]      FIG. 11B  is a side view of the aircraft of  FIG. 11A  with a spout assembly according to a yet a different embodiment of the present invention. 
           [0035]      FIG. 11C  is a partial schematic representation of the inlet of an F135 engine and lift fan. 
           [0036]      FIG. 11D  is a partial schematic representation of the inlet of an F100 engine. 
           [0037]      FIG. 11E  is a photographic representation of the inlet of an RB199 engine. 
           [0038]      FIG. 11F  is a photographic representation of the inlet of an F135 engine. 
           [0039]      FIG. 12A  is a side elevational view of an aircraft having a turboprop engine. 
           [0040]      FIG. 12B  is a schematic representation of components including the engine, gear box, and propeller located within a nacelle, and representative of the engine mounting in  FIG. 13A . 
           [0041]      FIGS. 13A and 13B  are drawings of multiple embodiments V.4 and V.5, respectively of spout assemblies according to various embodiments of the present invention. 
       
    
    
     ELEMENT NUMBERING 
       [0042]    The following is a list of element numbers and at least one noun used to describe that element. It is understood that none of the embodiments disclosed herein are limited to these nouns, and these element numbers can further include other words that would be understood by a person of ordinary skill reading and reviewing this disclosure in its entirety. 
         [0000]    
       
         
               
               
             
           
               
                   
               
             
             
               
                 9 
                 Needle 
               
               
                 10 
                 engine 
               
               
                 10.2 
                 lift fan 
               
               
                 10.3 
                 gear box 
               
               
                 10.4 
                 propeller 
               
               
                 10.5 
                 direction of compressor rotation 
               
               
                 10.6 
                 bullet nose 
               
               
                 11 
                 inlet 
               
               
                 11.5 
                 front hub cover 
               
               
                 11.6 
                 shaft 
               
               
                 11.7 
                 strut 
               
               
                 11.8 
                 inner diametral surface of inlet 
               
               
                 12 
                 fan 
               
               
                 12.5 
                 splitter 
               
               
                 12.6 
                 compressor inlet quadrants 
               
               
                 13 
                 compressor 
               
               
                 14  
                 combustor 
               
               
                 15 
                 turbine 
               
               
                 16 
                 exhaust 
               
               
                 17 
                 fan bypass housing 
               
               
                 18 
                 bypass vanes 
               
               
                 19 
                 bypass structural strut 
               
               
                 20 
                 washing system 
               
               
                 21 
                 vehicle 
               
               
                 22 
                 source of chemicals 
               
               
                 23 
                 boom 
               
               
                 24 
                 source of water 
               
               
                 25 
                 source of electricity 
               
               
                 26 
                 source of gas 
               
               
                 27 
                 nucleation device 
               
               
                 28 
                 foam output 
               
               
                 29 
                 pump 
               
               
                 30 
                 nozzle 
               
               
                 32 
                 effluent collector 
               
               
                 33 
                 hose 
               
               
                 34 
                 support 
               
               
                 35 
                 reservoir 
               
               
                 37  
                 containment wall 
               
               
                 38 
                 heater 
               
               
                 40 
                 foaming system 
               
               
                 41 
                 foam connection 
               
               
                 42 
                 tubing 
               
               
                 50  
                 spout assembly 
               
               
                 51 
                 spout nozzle 
               
               
                 52 
                 spout quick connection 
               
               
                 53 
                 spout member, rigid; segment 
               
               
                 54 
                 spout attaching mechanism 
               
               
                 55 
                 spout extension 
               
               
                 56 
                 spout nozzle actuator/servo 
               
               
                 57 
                 spout ball joint 
               
               
                 58  
                 spout socket joint 
               
               
                 59 
                 pivotal coupling 
               
               
                 60  
                 receptacle 
               
               
                 62  
                 sensor 
               
               
                 64 
                 bracket 
               
               
                 70 
                 yardstick 
               
               
                 80 
                 processing unit (recycle, purify) 
               
               
                 90  
                 aircraft 
               
               
                   
               
             
          
         
       
     
       DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0043]    For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. At least one embodiment of the present invention will be described and shown, and this application may show and/or describe other embodiments of the present invention, and further permits the reasonable and logical inference of still other embodiments as would be understood by persons of ordinary skill in the art. 
         [0044]    It is understood that any reference to “the invention” is a reference to an embodiment of a family of inventions, with no single embodiment including an apparatus, process, or composition that should be included in all embodiments, unless otherwise stated. Further, although there may be discussion with regards to “advantages” provided by some embodiments of the present invention, it is understood that yet other embodiments may not include those same advantages, or may include yet different advantages. Any advantages described herein are not to be construed as limiting to any of the claims. The usage of words indicating preference, such as “preferably,” refers to features and aspects that are present in at least one embodiment, but which are optional for some embodiments, it therefore being understood that use of the word “preferably” implies the term “optional.” 
         [0045]    Although various specific quantities (spatial dimensions, temperatures, pressures, times, force, resistance, current, voltage, concentrations, wavelengths, frequencies, heat transfer coefficients, dimensionless parameters, etc.) may be stated herein, such specific quantities are presented as examples only, and further, unless otherwise explicitly noted, are approximate values, and should be considered as if the word “about” prefaced each quantity. Further, with discussion pertaining to a specific composition of matter, that description is by example only, and does not limit the applicability of other species of that composition, nor does it limit the applicability of other compositions unrelated to the cited composition. 
         [0046]    Various references may be made to one or more methods of manufacturing. It is understood that these are by way of example only, and various embodiments of the invention can be fabricated in a wide variety of ways, such as by casting, sintering, welding, electrodischarge machining, milling, as examples. Further, various other embodiment may be fabricated by any of the various additive manufacturing methods, some of which are referred to 3-D printing. 
         [0047]    This document may use different words to describe the same element number, or to refer to an element number in a specific family of features. It is understood that such multiple usage is not intended to provide a redefinition of any language herein. It is understood that such words demonstrate that the particular feature can be considered in various linguistical ways, such ways not necessarily being additive or exclusive. 
         [0048]    Incorporated herein by reference in its entirety is PCT application US2014/058865, filed Oct. 2, 2014, and titled CLEANING METHOD FOR JET ENGINE. 
         [0049]      FIG. 1A  is a graphical representation of a washing cleaning system  20  with spout  50  according to one embodiment of the present invention. Illustrated is a washing system  20  applied to the cleaning of a gas turbine engine  10  mounted on aircraft  90 , while it is understood that various embodiments of the present invention contemplate the cleaning of any object. Washing system  20  ‘provides foamed cleaning product via nozzle  30 , into the inlet  11  of engine  10 , and/or it can at the same time or in combination with, provide cleaning product (foam) via hose  33  and through spout  50 . In still further embodiments of the present invention, a foamed cleaning product is provided through spout  50  into the engine core, and an atomized liquid cleaning product (the same or different cleaning product as the foamed product) is provided into the engine inlet via an atomizing nozzle  30 ’ (not shown). 
         [0050]    Spout  50  is placed and attached to engine  10  between the fan  12  section and compressor  13  section. Spout  50  is adapted and configured for delivery of a foamed cleaning product into the object to be cleaned. Therefore, the form and dimensions of spout  50  are selected to provide the foamed product with minimal changes to the structure and energy state of the foam. In some embodiments, the various flow features of spout assembly  50  are selected so as to not atomize the foam, and instill other embodiments to have minimal pressure drop, so as to not substantially compress the foam structure. In some embodiments, the nozzle assembly has a pressure drop under 50 psi (the pressure drop from foam flowpath to ambient pressure). However, the present invention contemplates yet other embodiments in which the pressure drop is less than about 100 psi. 
         [0051]      FIG. 1B  is a block diagram representation of a system according to one embodiment of the present invention for a liquid pump  29  receives a supply of liquid cleaner from a source  22 . The pressurized cleaning liquid is provided to a nucleation device  27 . Also provided to the nucleation device  27  is pressurized gas from a source  26 . Source  26  can be from a nearby building, a cylinder of pressurized gas, or from a pump. Nucleation device  27  mixes the cleaning liquid and the gas to a higher energy, foamed state. The foam output from device  27  is provided to the inlet of spout assembly  50 , and from nozzle  51  into the inlet of the engine. 
         [0052]    Although what is shown and described is the application of a cleaning system  20  to a conventional high bypass fan engine, it is further understood that yet other embodiments are applicable to any type of gas, steam, or water turbine, including as examples pure turbo jets, leaky (low bypass) turbo jets, turbo props, unducted fan engines, and engines in which the fan is driven via gearing. 
         [0053]      FIG. 2A  graphical represents the cross-section view of engine  10  with spout assembly  50  in place and attached to fan bypass vanes  18 . The distal end of spout assembly  50  preferably curves around the nose of a splitter  12 . 5  that separates the air propelled by the fan into either the bypass duct or the engine core.  FIG. 2B  graphically represents a close up view of the spout  50  placed such that the spout nozzle  51  allows for cleaning of product (foam) to enter the compressor  13  section effectively. 
         [0054]      FIG. 2C  demonstrates placement of spout  50 , such that the directed injected chemical products (such as cleaning foam and water) enter the compressor  13  section; while it is understood that the presented invention spout  50  contemplates placement to be anywhere along the intake annulus of compressor  13 .  FIG. 3A  permits persons of ordinary skill in the art to visualize that multiple spout assemblies  50  can be placed at any circumferential location along the annulus of compressor inlet. 
         [0055]      FIG. 3B  further represents a close up view of the spout nozzle  51  and spout  50  attached to bypass fan structure  19  and placed generally below the centerline of the engine. Nozzle  51  hooks around the annulus ring edge  12 . 5  (splitter) of compressor  13  of engine  10 .  FIG. 3B  shows that the distal most nozzle  51  of spout assembly  50  is located proximate to the outer flow diameter of the splitter nozzle of the engine on the core flow side. However, those of ordinary skill in the art will recognize that the length of the 180 degree bend can be extended so as to place spout nozzle  51  at different radial locations, including locations closer to the inner diameter of the core flowpath, as well as locations generally above the centerline, which may assist in providing an even distribution of flow within the engine. 
         [0056]      FIG. 4  are drawings of various spout assembly  50  embodiments. In one embodiment, the spout assembly  50  includes a quick connect fluid connection  52  followed by one or more pipe members  53  and a nozzle  51 . Spout  50  can also be one rigid pipe member  53  pre-shaped to a specific engine model as shown in version V.3. In some embodiments, it is preferably to have at least one pipe member  53  that provides a substantially open flowpath with rigid walls. It is anticipated that the use of some embodiments will be facilitated by having a rigid section for improved handling so as to better place the J nozzle from a distance (i.e., such as the length of the nacelle fan duct or any internal fan duct). Spout  50  in some embodiments is contemplated to also allow for flexibility and maneuverability, as in versions V.1 and V.2. V.1 is shown in the form of a ball and socket (similar to an aquarium ball and socket pipe, by Lifeguard Aquatics model ARP270850), where it can have multiple segments, and end with nozzle  51 . V.2 is shown with an extension  55  of dimension t, which can be useful in those spout assembly embodiments being adapted to engines of different sizes and configurations. 
         [0057]    All versions may or may not have an attachment mechanism  54  that couples assembly  50  to one of the radial struts  19  in the bypass duct. Yet mechanism  54  may alternatively also couple to the bypass housing  17  (not shown). 
         [0058]    It can be seen that V.2 is similar to the assembly  50  shown in  FIG. 3A . In contrast, V.3 shows a member  53  that extends distal nozzle  51  to a location that is radially more inward than the location of the nozzle  51  of V.2. The assembly shown as V.1 further illustrates that the flow out of the distal nozzle  51  can be oriented to spray radially inward, or even partially forward, such that the foam is directed aft by the air exiting the rotating fan. Still further, V.1 and V.2 show that it is possible to have converging nozzles  51  in some embodiments of the present invention, wherein the convergence geometry is adapted and configured to provide slightly higher velocity to the foam, but to still not atomize the foamed fluid, or substantially change the characteristics of the foam cells. In a preferred embodiment, the inner flow path of the spout assembly is adapted and configured to provide no more than a minimal decrease in the energy state of the foamed product. 
         [0059]      FIG. 5  is a close up view of one embodiment of spout nozzle  51 . In this embodiment, the nozzle  51  is controlled with a motor/actuator  56  to rotate nozzle  51  and move the pointing vector (exit of product) in three-dimensional space. Motor/actuator  56  is shown schematically. It is understood that ball  57  and socket  58  can be adapted and configured to provide a static surface (on ball  57 ) coupled to one end of the actuator, and a movable surface (on socket  58 ) attached to the other end of the actuator. In yet another embodiment, nozzle  58  can be spring loaded to an angular position, such as directly aft (or parallel to the X-axis shown on  FIG. 5 ). On the opposite end of the actuator is a wire that, in one embodiment, attaches near the top of socket  58  (i.e., the same location as actuator  56  is attached to), the wire running along a guided path such as around the forwardmost curved end of member  53 , and then extending aft. The aft end of the wire (not shown) is attached to a device such as a linear actuator. The actuator can pull on the wire, and thus cause socket  58  (which is coupled to ball  57  so as to move and be guided along a particular path by a track between the socket and ball). Pulling on the wire causes the output vector of nozzle  51  to have increasingly more of a component along the Z-axis. Releasing the tension on the wire permits the spring to pull the socket  58  back toward its initial position. In yet another embodiment, nozzle  58  may have two or more motor/actuators  56  on a track and pinion system 90-degrees to each other around the socket  58  (coupled to ball  57 ), such that the actuation of each independent actuator  56  results in a range of nozzle  51  movement to point at a particular direction in 3-dimensional space. 
         [0060]      FIG. 6A  is a picture of spout  50  mounted inside a PW 4098 engine.  FIG. 7B -Left is a picture from the rear of bypass fan section Left side of engine  10 , and illustrates how spout  50  can go through fan vanes  18  and reach to hook around the inlet annulus of compressor  13  section. Illustrated is a contemplated quick connect  52  (Banjo  2 ″ cam lock) for connection to other components of the foam washing system  20 . 
         [0061]      FIG. 6B -Right is a picture from the rear of bypass fan section Right side of the engine. This embodiment is similar to that in  FIG. 7B -Left, and demonstrates that the spout assembly  50  can be placed at any (or multiple) locations inside the fan housing  17 . Attachment  54  location affixes safely spout  50  to fan vane  18  so that it does not shake or move off during operation. 
         [0062]      FIGS. 6C and 6D  are photographs that demonstrate placement and relative size of spout  50 , including above the centerline and lateral to the centerline, respectively. Some embodiments contemplate entry of the foamed product into the compressor at a vertically high location (such as  FIG. 6C ). The dispersion of foam is aided by the influence of gravity to provide even distribution within a compressor. In still further embodiments (such as  FIG. 6D ), a lateral location is preferred. It is expected that in some engines it is preferable to introduce the foamed product at a position generally lateral to the engine centerline, and with the rotation of the engine being generally upward at that point such that the rotating compressor blades immediately aft of the spout nozzle tend to lift the foamed product up and around the compressor flowpath. However, yet other embodiments of the present invention include spout nozzles located laterally to an engine centerline such that the rotation of the blades immediately aft of the nozzle move the foam initially downward toward the bottom of the flowpath. In still further embodiments, the annular compressor inlet includes a plurality of nozzles delivering foamed product in a quadrant of the annulus, aft of which the compressor blades initially move the foamed product with some upward vector.  FIG. 3A  identifies two such quadrants  12 . 6 A and  12 . 6 B. For foam that is provided in either of these quadrants, at least a portion of the foamed product is lifted toward the top of the engine. Spout  50  is placed at one or many locations at the same time during operation as shown by Position A and/or B. 
         [0063]      FIG. 6E  is a picture close-up of spout  50  from the front of engine  10  and just behind fan  12  blades. This contemplated simplified spout  50  invention has a hook that allows it to come from the rear of the bypass section and curve around the nose of the splitter to provide product (such as foam and water) via nozzle  51  into the compressor section  13 . 
         [0064]      FIG. 7  is a picture showing spout  50  with relative dimensions. Spout  50  in one embodiment is made of 2 inch PVC pipe with a curved hook nozzle  51  and quick-connect fitting  52 . The inner diameter of the delivery pipe of spout  50  is preferably greater than ¼ inch in order to not reduce the foam quality and cell size. More preferably, the inner diameter of the piping providing the foam is greater than about one inch. For those embodiments with smaller pipe diameters, it is preferable to have multiple points for foam entry into the engine flowpath. By having multiple nozzles for delivery of foam, the total flow area of the nozzles if roughly the same as the cross sectional flow area of the delivery pipe. In some embodiments, the foam is initially generated in a nucleation chamber having an outlet with a cross sectional flow area (as described in the referenced PCT application). Preferably, the flow area of the flowpath between the outlet of that nucleation chamber to the aperture of nozzle  51  is substantially constant. In those applications having smaller diameter pipes for nozzle assembly  50 , it is preferred that there be a sufficient number of nozzles used to provide the same total flow area as the cross sectional flow area of the outlet of the nucleation chamber. However, the present invention does contemplation reductions in this flow area from creation in the nucleation chamber to injection into the engine of up to about twenty percent, and further other embodiments provide for increases in that flow area. 
         [0065]      FIG. 8A  is a picture of spout  50  placed on an aircraft with small to medium sized engines (General Electric CF34) by way of example. Spout  50  is placed between fan bypass housing  17  and engine  10  core.  FIG. 8B  is another view to depict placement of spout  50  and affixed to the nacelle fan housing  17  via adjustable attachment mechanism  54 .  FIG. 9  is a schematic that demonstrates the use in systems having multiple spout assemblies  50  (i.e. Lance  1 , Lance  2 , etc.), each provided with foam from one or more nucleation chambers in system  20  in conjunction of foam wash system  20 . 
         [0066]    Referring again to  FIG. 7 , it can be seen that in one embodiment the spout assembly  50  maintains a generally circular cross sectional shape along the foam flowpath from quick connect  52  to nozzle  51 . As best perceived from the upper right photographic representation of  FIG. 7 , the spout assembly  50  has a forward-projecting frontal area that can be considered as a rectangle with opposing rounded ends separated by flat, linear sides. Further, it can be seen that the aerodynamic shape of spout assembly  50  as shown in  FIG. 7  has a larger diameter directly in front of the engine flow splitter where two pieces of tubing come together, and then blending aft along the curved 90 degree sections of tubing (see  FIG. 11A ). 
         [0067]    However, yet further embodiments of the present invention contemplate “J” sections (i.e., the J section seen in the upper left corner of  FIG. 7 ) that are adapted and configured for reduced aerodynamic disturbance into the fan and compressor flowpaths, but still maintaining sufficiently large cross sectional flow area so as to not reduce the quality of the foam. As one example, the forward-facing, rounded blunt nose of the J section (seen in the upper left corner of  FIG. 7 ) can be replaced with a more tapered and pointed shape so as to create less aerodynamic disturbance when air exiting from the fan impinges on the stagnation point of the J section. 
         [0068]    Still further, and referring to the upper right corner of  FIG. 7 , it can be seen that the circular exit area of the J-section is spaced apart from the outer diameter of the core flowpath. In yet other embodiments, the exit of the J section is a flatter and more squared annular sector that is located more closely to the outer diameter of the core flowpath (i.e., the outwardmost inner surface of the splitter). A version of such a foam exit is shown in  FIG. 10B . The nozzle shown in  FIG. 10B  further includes a central locating feature that is adapted and configured to fit over the front of a compressor inlet guide vane. By achieving a coupling between the J section and the leading edge of the inlet guide vanes it is possible to enhance the circumferential (lateral) stability of the spout assembly relative to the compressor inlet and fan bypass struts  19 , and still further to minimize the possibility of the forwardmost end of the spout assembly  50  coming loose and entering the compressor as a foreign object. 
         [0069]    Still further embodiments of the present invention pertain to the cleaning of engines with relatively long aircraft inlet structures, and further including those engines receiving air through a “serpentine” or S-shaped inlet duct. Such inlets are typically found on various military aircraft. The additional length and/or S-shape to the duct presents additional problems to the maintenance crew. In some cases, the length and/or shape of the duct prevents the use of a straight, unsupported spout assembly. In some cases the length is great enough that an unsupported spout assembly could pose a risk to damaging the interior surface of the inlet, especially if the inlet has applied onto it coatings that should not be touched or scratched. In yet other embodiments, the serpentine shape of the duct may prevent the maintenance personnel from having a clear line of sight of the engine inlet, thus making it difficult to know if the spout assembly has been correctly located. 
         [0070]    Various embodiments of the present invention include spout assemblies that comprise rigid tubing in a piecewise segmented shape, or alternatively in a curved shape. In still further embodiments, the segments may be attached by means of pivoting joints so as to permit maintenance personnel to change the orientation of one segment relative to another segment. These pivoting joints may be pivotal about a single axis, whereas in other embodiments the joints permit swiveling about two axes. However, yet other embodiments recognize that some maintenance operations may prefer spout assemblies that have a shape adapted and configured for a single family of inlets (such as the inlets of a single family of aircraft, such as for the F-35). In such cases, the spout assemblies may be pre-formed from preferably rigid tubing to the specific shape, with (optionally) no pivoting joints. 
         [0071]    In still further embodiments, the spout assemblies include means for positively locating the spout assembly relative to the face of the engine. Such locating means can include one or more features on the end of the spout that at adapted and configured to have shapes that are complementary to the shape of an engine inlet feature. As one example, some engines include relatively pointed, conical engine covers  11 . 5 , and seen in  FIG. 11F . With some engines, these hub covers (sometimes referred to as a “bullet” nose) are stationary, having a fixed location relative to inlet struts  11 . 7 . In yet other embodiments, the hub cover  11 . 5  may be a rotating piece. 
         [0072]    In some embodiments, the spout assembly would include a complementary-shaped feature (such as a “funnel”) on the end of the spout assembly. The maintenance personnel can guide the complex-shaped spout assembly through a serpentine inlet and place the funnel-shaped receptacle onto the conically-shaped front cover  11 . 5 . Preferably, the foam nozzles are located circumferentially around the end receptacle of the spout assembly, although the present invention also contemplates those embodiments in which the foam exit nozzles are one or more annular, sector-portions located within the interior of the conical and receptacle. 
         [0073]    In still further embodiments, the distalmost end of the spout assembly can include one or more receptacles that have a shape that is complementary to a portion of one or more struts  11 . 7 . Still further, yet other embodiments can include locating features that come into contact with the inner diametral surface  11 . 8  of the engine inlet. In this latter case, these locating features can include semi-rigid struts attached at one end to the spout assembly, and having at the other end a rotatable wheel, as one example. The semi-rigid nature of such a locating feature lessens the chance of damage to the inlet, since this locating bracket simply bends out of the way if brought into contact with the inner surface of the inlet duct. Still further, having a rotating wheel (or ball) on the end of the locating strut further limits any scratching of the inlet interior surface 
         [0074]      FIGS. 11D and 11E  show examples of other front hub covers  11 . 5  on yet other engines. A corresponding receptacle on the distalmost end of the spout assembly would be adapted and configured to provide positive location on these surfaces. It is understood that the receptacle need not have a continuous, three dimensional contact surface. Optionally, the means for locating can include, as one example, one or more rings that touch the corresponding hub cover  11 . 5  and limit the aftward axial movement of the spout assembly when the spout assembly is fully inserted into the inlet. 
         [0075]      FIG. 11C  shows another type of propulsion package that includes a lift fan powered by a shaft  11 . 6  coupled to the front face of the engine. In such embodiments, one spout assembly can include a locating receptacle that provides positive location on the hub assembly  11 . 5  of the lift fan (if stationary), or alternatively on the struts, the inner surfaces of the flow surface, or on adjacent aircraft or lift fan static features. Still further, a spout assembly for providing foam to the engine would include a receptacle that is placed in contact with the cylindrical cover of the shaft  11 . 6 . As one example, such a receptacle could be a complementary-shaped cylindrical cover that has an angular extent of less than about one hundred eighty degrees. A plurality of foam exits (such as in a partially toroidal shape) can be placed around the receptacle of the shaft cover to provide foam to the engine inlet. 
         [0076]    Various embodiments of the present invention include the following apparatus and methods A, B, and C for generating foam from a liquid cleaning agent and pressurized gas: 
         [0000]    A. One embodiment of the present invention pertains to an apparatus for foaming a water soluble liquid cleaning agent. Some embodiments include a housing defining an internal flowpath, the flowpath having first, second, and third flow portions arranged sequentially, said housing having a gas inlet, a liquid inlet for the water soluble cleaning agent, and a foam outlet, the first flow portion including a gas plenum that is adapted and configured for receiving gas under pressure from the gas inlet and including a plurality of apertures, the plenum and the interior of the housing cooperating to form a mixing region receiving liquid from the liquid inlet and receiving gas expelled from the apertures, the first portion providing a first foam of the liquid and the gas into the internal flowpath, the second flow portion receiving the first foam and flowing the first foam past a foam growth member adapted and configured to provide surface area for attachment and merging of cells of the first foam to create a second foam; and the third flow portion receiving the second foam and flowing the second foam through a foam structuring member adapted and configured to reduce the size of at least some of the cells of the second foam to create a third foam provided to the foam outlet.
 
B. Another embodiment of the present invention pertains to a method for foaming a water soluble liquid cleaning agent. Some embodiments include mixing the water soluble liquid cleaning agent and a pressurized gas to form a first foam, flowing the first foam over a member and increasing the size of the cells of the first foam to form a second foam, and flowing the second foam through a structure and decreasing the size of the cells of the second foam to form a third foam.
 
C. Yet other embodiments pertain to an apparatus for foaming a water soluble liquid cleaning agent. Some embodiments include means for mixing a pressurized gas with a flowing water soluble liquid to create a foam, means for growing the size of the cells of the foam, and means for reducing the size of the grown cells.
 
         [0077]    Although various embodiments of the present invention have been shown and described in conjunction with various means for creating a foamed cleaning agent, it is understood that in yet other embodiments, the foamed cleaning agent can be created in any manner. Various embodiments of the present invention pertain simply to any of the various spout assemblies, and their alternatives, shown and described herein, without any means for creating foam of any type. 
         [0078]    Still further embodiments of the present invention contemplate engine washing of buried engines in which the front bullet nose of the engine is a rotating component. In such applications the receptacle at the end of the spout assembly can be located on any static structure on the front of the engine, or in the aircraft inlet proximate to the engine front face. In yet other embodiments, the receptacle on the spout assembly is supported by a bearing and is able to spin with the bullet nose. It is understood that the engine foam washing procedure preferably uses the engine starter to rotate the engine. Therefore, the engine and the spout receptacle would be rotating at relatively low rpm. 
         [0079]      FIG. 11A  shows the view from the top of the planform of an aircraft  90  with a pair of buried engines  10 , such as an F-22.  FIG. 11B  shows an orthogonally arranged side view of the aircraft  90  and inlet  11 . It can be seen in  FIG. 11A  that the inlet varies in position laterally, and in  FIG. 11B  it can be seen that the inlet  11  flowpath varies in position vertically. As a result, some embodiments employ a spout assembly  50  that includes multiple segments  53  separated and held in relative orientation by one or more pivotal couplings  59 . 
         [0080]      FIG. 11A  shows a first spout assembly  50  having two preferably rigid piping segments  53  connected together by a single pivoting coupling  59 . It can be seen that the foam exit nozzle  51  is located a first, longer distance from the front face of engine  10 . In contrast, the spout assembly  50  shown in  FIG. 11B  includes multiple rigid segments  53 , interconnected and oriented relative to one another by a pair of pivotal joints  59 . The spout assembly  50  of  FIG. 11B  has more degrees of freedom for placement of foam nozzle  51 , as compared to the spout assembly  50  of  FIG. 11A . Because the spout assembly of  FIG. 11B  has more degrees of freedom than the spout of  FIG. 11A , the spout of  FIG. 11B  can be oriented to more closely follow the centerline of the S-shaped inlet duct  11 , and because of these additional degrees of freedom the nozzle  51  can also be located in a more desirable location. In addition, the increased number of degrees of freedom permits additional total length and reach of the spout assembly into the inlet, with less likelihood of rubbing the inner surface of the inlet duct  11 . 
         [0081]      FIGS. 12A and 12B  depict yet another embodiment of the present invention directed toward turboprop applications.  FIG. 12A  shows a C- 130 J aircraft  90 , with a nacelle  9  and propeller  10 . 4 .  FIG. 12B  shows schematically that nacelle  9  includes in it an engine  10  driving a gearbox  10 . 3  by way of a shaft  11 . 6 . The inlet  11  is located underneath gearbox  10 . 3 , although other embodiments of the present invention pertain to inlets located to either side of the gearbox, above the gearbox, or other locations. A multiple segment spout assembly  50  is shown entering inlet  11  just aft of propeller  10 . 4 , and being adapted and configured to point the nozzle  51  (supported by a pivotal coupling  59 ) toward the inlet face of engine  10 . 
         [0082]      FIG. 13  shows versions V.4 and V.5 of spout assemblies according to other embodiments of the present invention. At the top of  FIG. 13  is a spout assembly  50  labeled as “V.4.” It can be seen that in this version of the spout assembly there are three segments  53  providing a foam flowpath from an inlet at a quick connection  52 , all the way to a foam delivery nozzle  51 . In some embodiments, the first and last segments  53  are generally parallel, since the centerline of the face of the aircraft inlet and the centerline of the engine inlet may be parallel. A central segment  53   a  separates the two, providing an approximate S-shape. In some embodiments, the segments are separated by pivotal joints  59 , which permit adjustable rotation of one segment relative to another. In still further embodiments, the three segments are attached together statically, such that relative rotation of one segment to another is not possible after the segments have been attached together. Still further embodiments contemplate four or more segments, so as to more accurately follow the centerline of the aircraft serpentine inlet, and/or to more accurately locate the foam delivery nozzle  51  to the desired location. 
         [0083]    The bottom of  FIG. 13  shows a spout assembly  50  referred to as “V.5” that is adapted and configured with a distalmost end that interfaces with, and positively locates relative to, the inlet face of an engine  90 . Shown in this figure is a photographic representation of an F414 engine. Spout assembly  50  includes located proximate to its distalmost end a receptacle  60  having a generally conical shape. The conical shape of receptacle  60  is adapted and configured to positively locate on the bullet nose  10 . 6  of the engine. Receptacle  60  is attached to spout assembly  50  by means of a bracket  64 . In some embodiments, this bracket further includes one or more outwardly extending legs. Such legs  64  (such as those shown in  FIG. 1B ) assist in locating of foam exit  51  to the proper location within a serpentine duct. These legs in some embodiments are flexible, and bend in reaction to a force that is about the same or slightly greater than the supported weight of the spout assembly. Still further, in some embodiments these legs include a rotating wheel or ball at the end so that any incidental contact with the inlet walls does not scratch any coating. 
         [0084]    Preferably, spout assembly  50  includes attached proximate to the nozzle  51  one or more sensors  62 . In one embodiment, a sensor  62  includes a borescope that permits visual sighting by the maintenance personnel of the distalmost end of the spout assembly as it is being moved through the serpentine inlet. In yet other embodiments, there can be sensors  62  that change capacitance, resistance, magnetic permeability, or other quality in the presence of the materials of the engine inlet face. Sensor  62  sends a signal (by wire along the length of the spout assembly, or wirelessly) to the maintenance personnel that use the signal to locate the nozzle  51  within the inlet  11 . 
         [0085]    While the inventions have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. 
         [0086]    Various aspects of different embodiments of the present invention are expressed in paragraphs X1, X2, and X3 as follows: 
         [0087]    X1. One aspect of the present invention pertains to a system for providing a gas-foamed liquid cleaning agent to a turbine engine. The system preferably includes a gas pump or reservoir of pressurized gas providing gas at a pressure higher than ambient pressure. The system preferably includes a liquid pump providing the liquid cleaner at a pressure. The system preferably includes a nucleation device receiving pressurized gas and pressurized liquid, and a foam outlet, the nucleation device turbulently mixing the pressurized gas and the pressurized liquid to create a foam. The system preferably includes a spout assembly having a supply section flowing the foam in a first direction toward a delivery nozzle, the nozzle flowing the foam in a second direction substantially opposite to the first direction, the nozzle being adapted and configured to deliver a low velocity stream of foam to the compressor inlet. 
         [0088]    X2. Another aspect of the present invention pertain to a method for providing a gas-foamed liquid cleaning agent to a jet engine. The method preferably includes providing a source of a liquid cleaning agent, a liquid pump, a source of pressurized gas, a turbulent mixing chamber, and a flow-reversing spout assembly having a non-atomizing exit nozzle. The method preferably includes mixing pressurized gas with pressurized liquid in the mixing chamber and creating a supply of foam. The method preferably includes placing the spout assembly with the exit nozzle in front of the engine core. The method preferably includes streaming the supply of foam into the engine core from the nozzle. 
         [0089]    X3. Yet another aspect of the present invention pertains to a system for providing a gas-foamed liquid cleaning agent to a turbine engine. The system preferably includes a source of gas at a pressure higher than ambient pressure. Some aspects include a source of gas other than air, and still further embodiments contemplate providing pressurized gas (including air) by any method, including by way of pressurized cylinders, or by way of a pressurized gas system that is present at the cleaning facility (such as a supply of “shop air”). The system preferably includes a nucleation device that creates a foam. The system preferably includes a spout assembly having a foam inlet for receiving foam from the nucleation device, a substantially rigid supply section flowing the foam from the foam inlet toward a foam delivery nozzle, the nozzle including a female receptacle adapted and configured to receive therein a complementary-shaped male feature of the engine, the nozzle being adapted and configured to deliver a low velocity stream of foam to the engine inlet. Alternatively, the spout assembly may include one or more locating struts adapted and configured to locate the foam nozzle centrally within the inlet, and proximate to the front face of the engine. 
         [0090]    Yet other embodiments pertain to any of the previous statements X1, X2, or X3, which are combined with one or more of the following other aspects. It is also understood that any of the aforementioned X paragraphs include listings of individual features that can be combined with individual features of other X paragraphs. 
         [0091]    Wherein the supply section is substantially rigid. 
         [0092]    Wherein the supply section has a first length, the engine is located in a nacelle having a cowl, the cowl having a second length, and the first length is longer than the second length. 
         [0093]    Wherein the nozzle is placed near the hub of the compressor. 
         [0094]    Wherein the nozzle or receptacle is adapted and configured to fit between a pair of adjacent inlet guide vanes of the compressor. 
         [0095]    Wherein the foam at the exit of the nucleation device has a cell structure, and the internal passageways of the spout assembly are adapted and configured to generally maintain the cell structure of the foam. 
         [0096]    Wherein the pressure at the foam exit is less than about one hundred pounds per square inch. 
         [0097]    Wherein the pressure at the foam exit is less than about fifty pounds per square inch. 
         [0098]    Wherein the exit area of the nozzle is greater than about three fourths of a square inch. 
         [0099]    Wherein the liquid cleaning agent is water soluble and the velocity of the foam exiting the delivery nozzle is less than about twenty feet per second. 
         [0100]    Wherein the delivery nozzle is supported in an approximate J-shape and including a foam inlet linearly spaced apart from a hooked end having a foam exit. 
         [0101]    Wherein the spout assembly includes a coupling in the supply section that can be articulated about at least one axis. 
         [0102]    Which further comprises a frame having wheels, and the air pump, the liquid pump, and the nucleation device are attached to the frame. 
         [0103]    Wherein the frame is part of a ground vehicle. 
         [0104]    Wherein the frame is part of a ground cart having an electric motor to drive the liquid pump. 
         [0105]    Wherein the spout assembly includes one or more sensors that provide a signal corresponding to the location of the distalmost end of the spout assembly relative to the front face of the engine. Such sensors can include a proximity sensor having resistance, capacitive, or other quality that changes in the presence of the front face of the engine. In still further embodiments the sensor can be an optical system, such as one having a lens providing an optical signal to a fiber optic cable, the optical signal being displayed visually to the maintenance personnel. One such example of an optical system is a borescope.