Apparatus and method for foaming cleaning agents - Patents.com

Abstract

A device that foams water-soluble liquid cleaning agents. The housing of the device defines an internal flow path having a first flow portion, a second flow portion, and a third flow portion, and includes a gas inlet, a liquid inlet for an aqueous cleaning agent, and a foam outlet. The first flow portion receives gas under pressure from the gas inlet and includes a gas plenum configured with multiple openings, with the plenum and the housing interior forming a mixing region that receives liquid from the liquid inlet and gas from the openings. The first portion delivers a first foam of liquid and gas to the internal flow path. The second flow portion flows the first foam through a foam growth member configured to have a surface area for attachment and fusion of the first foam cells to form a second foam. The third flow portion flows the second foam through a foam structuring member configured to reduce the size of at least some of the second foam cells to form a third foam that is delivered to the foam outlet.

Description

[Technical Field]

[0001] Various embodiments of the present invention relate to apparatus and methods for cleaning devices that include gas paths, including combustion chambers, and in particular to apparatus and methods for cleaning gas turbine engines. [Background technology]

[0002] Turbine engines extract energy and pass it through a wide range of stages to generate power. The energy can range from steam to fuel combustion. The extracted power is then used for electricity, propulsion, or general motive power. Turbines operate by converting fluid and gas flows into usable energy to power helicopters, aircraft, tanks, power plants, ships, specialized vehicles, and cities. During use, the gas pathways of these devices become contaminated with debris and contaminants such as minerals, sand, dust, soot, and carbon. This contamination reduces the device's performance and requires maintenance and cleaning.

[0003] Turbines are well known in many forms, such as jet engines, industrial turbines, or aeroderivative units on land and ships. The internal surfaces of devices such as aircraft or helicopter engines can accumulate contaminants, which can impede engine airflow and reduce performance. This can increase fuel consumption, shorten engine life, and reduce available power.

[0004] The simplest and most cost-effective means of maintaining an engine and restoring performance is to properly clean it. Many methods are available, such as mist, spray, and steam systems, but all of these cannot reach the entire or deep parts of the engine gas path.

[0005] Engine telemetry or diagnostic tools have become routine features for monitoring engine health, but the use of such tools to monitor, induce, or quantify improvements from foam engine cleaning has not previously been utilized. Summary of the Invention [Problem to be solved by the invention]

[0006] Various embodiments of the present invention provide novel and unobvious methods and apparatus for cleaning such power plants. [Means for solving the problem]

[0007] A foam material is introduced into the gas path inlet of the turbine equipment while it is off-line. The foam coats and contacts the interior surfaces to scrape, remove and carry away contaminant material from the equipment.

[0008] One aspect of the present invention relates to an apparatus for foaming a cleaning agent. Some embodiments include a housing defining an internal flow path having a first flow section, a second flow section, and a third flow section, a gas inlet, a liquid inlet for the cleaning agent, and a foam outlet. The first flow section includes a gas plenum adapted and configured to receive gas under pressure from the gas inlet and include a plurality of openings, the gas plenum and the interior of the housing forming a mixing region that provides a first foam of liquid and gas. The second flow section receives the first foam and flows it through a foam growth matrix adapted and configured to have a surface area for cell attachment and fusion. The third flow section flows the second foam through a foam structuring member downstream of the first or second section, adapted and configured to reduce the size of at least a portion of the cells. It is understood that still other embodiments of the present invention contemplate a housing having only the first section, or first and second sections, or first and third sections, in various other nucleation devices.

[0009] Another aspect of the invention relates to a method for foaming a liquid cleaning agent. Some embodiments include mixing a liquid cleaning agent and a pressurized gas to form a first foam. Other embodiments include flowing the first foam through a member or matrix to form a second foam, increasing the cell size of the first foam. Still other embodiments include flowing the second foam through a structure, such as a mesh or a plate with one or more apertures, to form a third foam, decreasing the cell size of the second foam.

[0010] Yet another aspect of the present invention relates to a system for providing air-foamed liquid cleaning agents. Another embodiment includes an air pump or pressurized gas reservoir that provides air or gas at a pressure greater than ambient pressure, and a liquid pump that provides liquid under pressure. Yet another embodiment includes a nucleation device that receives pressurized air, a liquid inlet that receives pressurized liquid, and a foam outlet, where the nucleation device turbulently mixes the pressurized air and liquid to form foam. Yet another embodiment includes a nozzle that receives foam through a foam conduit, where the internal passage of the nozzle and conduit is adapted and configured to not increase turbulence in the foam, and the nozzle is adapted and configured to deliver a slow stream of foam.

[0011] Yet another aspect relates to a method for delivering an air-foamed liquid cleaning agent to an inlet of a jet engine installed in an aircraft. Some embodiments include providing a pressurized liquid cleaning agent source, an air pump, a turbulent mixing chamber, and a non-atomizing supply opening. Other embodiments include mixing pressurized air with pressurized liquid in the mixing chamber to form a foam supply. Still other embodiments include flowing the foam supply into the installed engine through the inlet or opening through various tubing attached to the engine.

[0012] Yet another aspect of the present invention relates to an apparatus for foaming an aqueous liquid cleaning agent. Some embodiments include a means for mixing a pressurized gas with a flowing aqueous liquid to form foam. Other embodiments include a means for growing the size of the foam cells and a means for reducing the size of the grown cells.

[0013] In various embodiments of the present invention, the effluent after a cleaning operation is collected and evaluated. This evaluation may include on-site analysis of the contents of the effluent, including whether specific metals or compounds are present in the effluent. Based on the results of this evaluation, a decision is made as to whether further cleaning is appropriate.

[0014] Yet another embodiment of the present invention relates to a method for evaluating the effectiveness of a cleaning operation, the evaluation being used to evaluate the terms of a contract. As an example, the contract may relate to the terms of an engine warranty provided by an engine manufacturer to an aircraft operator or owner. In yet another embodiment, the evaluation can be used to evaluate the terms of a contract relating to the engine cleaning operation itself. In yet another embodiment, the evaluation of the cleaning effectiveness on an engine can be used to evaluate the engine against establishing FFA maintenance criteria for the engine.

[0015] In one example, the evaluation method includes operating the engine in a commercial flight environment for approximately two months or more. In some examples, it is anticipated that this operation may include multiple flights per day and up to seven days of aircraft use per month. The method further includes operating a used engine to establish baseline characteristics. In some examples, the baseline characteristics are specific fuel consumption at a particular thrust level, engine pressure ratio, or rotor speed. In some alternatives, the method includes correcting this baseline data for environmental atmospheric characteristics. In yet another example, the baseline parameter is the elapsed time between engine startup from 0 rpm to idle speed. In yet another example, a baseline evaluation of a used engine includes evaluating engine startup time in the following manner: performing an initial startup of the engine, shutting down the engine, running the engine on the starter (without burning fuel) for a predetermined period of time, and, after running, performing a second engine startup and using the second engine startup time as the baseline startup time.

[0016] The method further includes cleaning the engine. This cleaning of the engine can include one or more successive cleaning cycles. After the engine is cleaned, the baseline test method is repeated. This second test result (of the cleaned engine) is compared to the baseline test result (of the used engine as received), and changes in engine characteristics are evaluated against contractual guarantees. As one example, the cleaning equipment operator may have presented contractual terms to the aircraft owner or operator regarding the improvements made by the cleaning method. Furthermore, in another example, the delta improvement provided by the cleaning method (or alternatively, the test results of the cleaned engine considered by itself) can be compared to contractual guarantees with the engine manufacturer (or the facility that performed the engine's previous overhaul or the engine licensee) to evaluate whether the cleaned engine meets these contractual terms.

[0017] In yet another embodiment, there is a cleaning method performed on an engine where a baseline test is used, the engine is cleaned, and the baseline test is performed twice. The comparison of the baseline test to the clean engine test can be used for any reason.

[0018] In yet another embodiment, the cleaning method includes operating the engine in a cleaning cycle, and this cleaning cycle (or a different cleaning cycle) is then applied to the engine. Preferably, the cleaning agent is provided to the engine at a relatively low rotational speed, preferably less than about half the normal idling speed of the engine.

[0019] In yet another embodiment, such as those engines supported substantially vertically, a cleaning agent can be applied to the engine when it is stationary (i.e., at 0 rpm). After a sufficient amount of agent has been applied, the engine can then be rotated at any speed, after which the cleaning agent can be washed off.

[0020] Yet another embodiment of the present invention relates to a method for cleaning an engine, including manipulating the temperature of a cleaning agent and / or the temperature of the engine being cleaned. In one embodiment, the cleaning system includes a heater adapted and configured to heat the cleaning agent prior to forming a cleaning foam. In yet another embodiment, the method includes a heater for heating air used to form the foam with the cleaning liquid. In yet another embodiment, the cleaning device includes one or more air blowers (similar to "alligator" space heaters used on construction sites) with a source of heated ambient air. These hot air blowers can be positioned at the inlet of the engine, and the engine can be free-running (i.e., running on a starter without burning fuel) for a predetermined period of time (which can be based on ambient conditions) or until a thermocouple or other temperature measurement device in a hot zone of the engine reaches a predetermined temperature. In yet another embodiment, the temperature of the engine prior to the introduction of the cleaning foam can be increased by starting the engine and operating it at idle for a predetermined period of time, after which the engine can be shut off prior to the introduction of the cleaning foam. In yet another embodiment, the engine can be allowed to run after stopping from idle and before introducing the agent to further achieve a consistent baseline temperature condition before introducing the foam. Yet another embodiment of the present invention contemplates any combination of preheated liquid agent, preheated compressed air used for foaming, an externally heated engine, and an engine "warmed" by one or more recent periods of operation.

[0021] In yet another embodiment of the present invention, the cleaning foam can be heated by providing a heating element within the device used to mix and form the cleaning foam.

[0022] It will be appreciated that the various devices and methods described in this Summary, as well as elsewhere in this application, can be expressed in many different combinations and sub-combinations, and all such useful, novel, and inventive combinations and sub-combinations are contemplated herein, with the recognition that explicit expression of each of these combinations is unnecessary.

[0023] Some of the figures shown herein may include dimensions. Additionally, some of the figures shown herein may be made from scaled drawings or scalable photographs. It is understood that such dimensions or relative scales within the figures are for illustrative purposes and are not to be construed as limiting. [Brief explanation of the drawings]

[0024] [Figure 1] Schematic of a gas turbine engine. [Figure 2] 1 is a schematic diagram of a cleaning device according to one embodiment of the present invention. [Figure 3A] Photograph of part of the apparatus in Figure 2. [Figure 3B] Photograph of a portion of the apparatus of FIG. 2 showing the provision of foam within the inlet of an installed engine. [Figure 3C] Photograph of a nozzle according to one embodiment of the present invention in front of an engine inlet. [Figure 3D] Photograph of a nozzle according to another embodiment of the present invention in front of an engine inlet. [Figure 4] Photograph of a foam structure according to one embodiment of the present invention. [Figure 6] Photographs of a portion of an engine's exhaust structure before and after being cleaned by one embodiment of the present invention. [Figure 7] 1 is a graph of the improvement in engine start time for an engine cleaned according to one embodiment of the present invention. [Figure 8] Photograph of an engine being washed on an engine test stand according to one embodiment of the present invention. [Figure 9] Photograph of a portion of the apparatus in Figure 8. [Figure 10] 1 is a graph of parameter improvements for an engine cleaned according to one embodiment of the present invention. [Figure 11] 1 is a graph of parameter improvements for an engine cleaned according to one embodiment of the present invention. [Figure 12A] 1 is a schematic diagram of a cleaning system according to one embodiment of the present invention. [Figure 12B] 1 is a schematic diagram of a cleaning system according to another embodiment of the present invention. [Figure 13A] Photograph of one embodiment of a portion of the device of FIG. 12A. [Figure 13B] Photograph of one embodiment of a portion of the device of FIG. 12A. [Figure 13C] Photograph of one embodiment of a portion of the device of FIG. 12A. [Figure 14A] An enlarged photograph of a portion of the device in Figure 13. [Figure 14B] An enlarged photograph of a portion of the device in Figure 13. [Figure 14C] An enlarged photograph of a portion of the device in Figure 13. [Figure 14D] An enlarged photograph of a portion of the device in Figure 13. [Figure 15A] Photograph of the interior of the cabinet in Figure 13. [Figure 15B] Photograph of the interior of the cabinet in Figure 13. [Figure 15C] Photograph of the interior of the cabinet in Figure 13. [Figure 15D] Photograph of the interior of the cabinet in Figure 13. [Figure 16A] Photograph of the components shown in Figure 15B. [Figure 16B] Photograph of the components shown in Figure 15B. [Figure 16C] Photograph of the components shown in Figure 15B. [Figure 16D] Photograph of the components shown in Figure 15B. [Figure 16E] Photograph of the components shown in Figure 15B. [Figure 16F] Photograph of the components shown in Figure 15B. [Figure 18A]1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18B] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18C] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18D] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18E] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18F] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18G] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18H] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18I] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18J] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18K] 1 is a cutaway schematic view of a nucleation chamber according to various embodiments of the present invention. [Figure 18L] 12A-12C are cutaway schematic views of nucleation chambers according to various embodiments of the present invention. FIG. 12B shows a schematic view of a nucleation chamber according to one embodiment of the present invention, cross section AA of nucleation chamber 1260. [Figure 18M] 18A-18C are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; FIG. 18C is an end view of nucleation chamber 1260 as viewed from 18M-18M in FIG. 18L; [Figure 18N] 18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged view of a portion of the apparatus of FIG. 18L. [Figure 18O]18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged schematic view of a portion of the apparatus of FIG. 18L. [Figure 18P] 18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged schematic view of a portion of the apparatus of FIG. 18L. [Figure 18Q] 18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged schematic view of a portion of the apparatus of FIG. 18L. [Figure 18R] 18A-18D are cutaway schematic views of nucleation chambers according to various embodiments of the present invention; FIG. 18B shows a schematic view of a nucleation chamber according to one embodiment of the present invention; and FIG. 18C is an enlarged schematic view of a portion of the apparatus of FIG. 18L. [Figure 19A] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 19B] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 19C] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 19D] CAD drawing of an aircraft with its engines installed and being foam washed. [Figure 19E] CAD drawings of multiple effluent collectors according to various embodiments of the present invention. [Figure 2-1A] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 2-1B] 1 is a pictorial diagram of an aircraft engine being cleaned by a system according to one embodiment of the present invention. [Figure 2-2] 1 is a pictorial representation of an aircraft engine being cleaned by a system according to one embodiment of the present invention and by one embodiment of an effluent capture device. [Figure 2-3]1 is a pictorial representation of an aircraft engine being cleaned by a system according to one embodiment of the present invention and by one embodiment of an effluent capture system, according to one aircraft scenario. [Figure 2-4] 1 is a pictorial representation of an aircraft engine with a variable foam effluent capture system being cleaned by a system according to one embodiment of the present invention; [Figure 2-5] 1 is a schematic and photo illustration of an aircraft engine being cleaned by a system according to one embodiment of the present invention; [Figure 2-7] Schematic of the cleaning process according to the present invention. [Figure 2-8A] 1 is a schematic diagram of an engine illustrating a foam injection system according to one embodiment of the present invention. [Figure 2-8B] 1 is a schematic diagram of an engine illustrating a foam injection system according to one embodiment of the present invention. [Figure 2-9A] 1 is a schematic diagram of an internal cutaway of an engine showing a foam connection system according to one embodiment of the present invention. [Figure 2-9B] 1 is a cutaway schematic of an engine with internal and external components showing a foam connection system according to one embodiment of the present invention. [Figure 2-10] 1 is a graph of engine cleaning cycle specifications according to one embodiment / method of the present invention. [Figure 2-11] 1 is a graph of one method for engine monitoring and benefit quantification according to one embodiment / method of the present invention. [Figure 2-12A] Photograph of an effluent collector according to one embodiment of the present invention. [Figure 2-12B] FIG. 12B is a front view of the device of FIGS. 2 to 12A, looking toward the rear. [Figure 2-12C] FIG. 12B is a rear view, facing forward, of the device of FIGS. 2 through 12A. DETAILED DESCRIPTION OF THE INVENTION

[0025] (element symbol) Below is a list of element numbers and at least one name used to describe the element. It is understood that none of the embodiments disclosed herein are limited to these names, and that these numbers may also include other terms that would be understood by one of ordinary skill in the art upon reading and studying this disclosure as a whole. [Table 1]

[0026] For the purposes of promoting an understanding of the principles of the invention, reference will be made to the illustrated embodiments and specific language will be used to describe the same. However, no limitation of the scope of the invention is intended thereby, and it will be understood that such alterations and further modifications in the illustrated devices, and such other applications of the inventive principles as exemplified therein, as would normally occur to one skilled in the art to which the invention pertains, are contemplated. Although at least one embodiment of the invention has been described and shown, the present application may show and / or describe other embodiments of the invention.

[0027] The term "the present invention" refers to a group of embodiments of the present invention, and it is understood that no single embodiment includes an apparatus, process, or composition that must be included in all embodiments unless expressly stated otherwise. Furthermore, while there is discussion of "advantages" provided by some embodiments of the present invention, it is understood that other embodiments may not exhibit these advantages, or may even exhibit different advantages. Any advantages discussed herein are not to be construed as limitations on any of the claims. The use of language indicating preferences, such as "preferably," refers to features and aspects that are present in at least one embodiment, but are optional in some embodiments.

[0028] The use of an N-series prefix in the designation (NXX.XX) refers to an element that is the same as the element without the prefix (XX.XX), except as shown and described. As one example, element 1020.1 is the same as element 20.1, except for the different configurations of element 1020.1 shown and described. Furthermore, common elements and common configurations of related elements may be depicted in the same manner with different numbers and / or may use the same symbols in different figures. Thus, it is not necessary to describe the configurations of 1020.1 and 20.1 that are the same, since these common configurations will be apparent to those skilled in the relevant art. Furthermore, it is understood that the configurations 1020.1 and 20.1 may be backward compatible, such that the configuration (NXX.XX) can include configurations that are compatible with various other embodiments (MXX.XX), as will be understood by those skilled in the art. This description convention also applies to the use of dash ('), double dash ("), and triple dash ("') suffix element numbers. Therefore, it is not necessary to describe the features of 20.1, 20.1', 20.1", and 20.1"' that are the same, since their common features will be apparent to one skilled in the relevant art.

[0029] Although various specific quantities (such as spatial dimensions, temperature, pressure, time, force, resistance, current, voltage, concentration, wavelength, frequency, heat transfer coefficient, dimensionless parameters, etc.) are set forth herein, such specific quantities are presented by way of example only and, unless expressly indicated otherwise, are approximations and should be considered as if the word "about" preceded each quantity. Furthermore, in any discussion of specific compositions, the description is by way of example only and is not intended to limit the applicability of that composition to other species or to other compositions unrelated to the recited composition.

[0030] Below follow paragraphs that describe particular embodiments of the present invention. In these subsequent paragraphs, some element numbers are prefixed with an "X" to indicate that the term refers to any of the similar structures shown in the figures or described in the text.

[0031] Shown and described herein in conjunction with various embodiments of the present invention are discussions of one or more tests that have been performed. It is understood that such examples are exemplary only and are not to be construed as limitations on any embodiment of the present invention. Furthermore, it is understood that embodiments of the present invention are not necessarily limited to or explained by the mathematical analyses presented herein.

[0032] Various references may be made to one or more processes, algorithms, methods of operation, or logic, accompanied by diagrams illustrating such organization in a particular sequence, it being understood that the order of such sequences is by way of example only and is not intended to limit any embodiment of the invention.

[0033] Various references may be made to one or more methods of manufacturing. These are by way of example only, and it will be understood that various embodiments of the present invention may be fabricated in a wide variety of ways, such as, by way of example, casting, centering, welding, electrical discharge machining, milling, etc. Additionally, various other embodiments may be fabricated by any of a variety of additive manufacturing methods, some of which are referred to as 3D printing.

[0034] This document may use different words to describe the same symbol or to refer to a symbol within a unique group of features (NXX.XX). It is understood that such plural usage is not intended to provide a redefinition of any language herein. It is understood that such words may be considered in various linguistic ways, and that such ways are not necessarily additive or exclusive.

[0035] Shown and described herein are one or more functional relationships among variables. While specific nomenclature for the variables can be provided, some relationships may include variables recognized by those skilled in the art for their meaning. For example, "t" can represent temperature or time, as readily apparent from its usage. However, it is further recognized that such functional relationships can be expressed in various equivalents using standard techniques of mathematical analysis (e.g., the relationship F=ma is equivalent to the relationship F / a=m). Furthermore, in embodiments where the functional relationships are implemented in an algorithm or computer software, it is understood that the algorithmized variables can correspond to the variables shown herein, where this correspondence includes scaling factors, control system gains, noise filters, or the like.

[0036] A wide variety of methods have been used to clean gas turbine engines: some users utilize water sprayed into the engine inlet, others utilize cleaning fluids sprayed into the engine inlet, and still others provide a solid abrasive material, such as walnut shells, into the engine inlet.

[0037] These methods have achieved varying degrees of success and have also caused varying degrees of problems. For example, some cleaning agents that are strong enough to clean the engine's high-temperature zones and are chemically acceptable on high-temperature zone materials are chemically unacceptable on materials used in the engine's low-temperature zones. Water washing, while gentle enough to be used on any engine material, is not effective at removing particularly difficult deposits and may leave silica deposits in some compressor stages. While several water-soluble cleaning agents are recognized in MIL-PRF-85704C, many users of these cleaning agents believe they are marginally successful in restoring performance to engine operating parameters, and others have noted that cleaning alone with these MIL cleaning agents may actually degrade some operating parameters.

[0038] Therefore, many aircraft operators are skeptical of some liquid cleaning methods, i.e., the claims made about how effective the liquid is in restoring performance to the engine. The cost of liquid washing includes the price of liquid washing the engine and the time the aircraft is taken out of service. Often, the benefits of liquid washing do not outweigh the costs incurred or provide only marginal commercial benefits.

[0039] Various embodiments of the present invention demonstrate the significant commercial benefits that can be obtained by foam washing of gas turbine engines. As demonstrated herein, engine foam cleaning can provide significant improvements in operating parameters, including improvements not obtainable with liquid washing. The reasons for the significant improvements realized by foam washing are not fully understood. Back-to-back engine tests have been performed on the same specific engine, in which an atomized liquid is introduced into the inlet, followed by a foam of the same liquid. In all cases, liquid (or foam) was observed in the engine exhaust region, indicating that the liquid (or foam) appears to wet the entire gas path. Nevertheless, the use of foam liquid provides significant improvements beyond any improvements of liquid washing in key operating parameters, such as engine start time, specific fuel consumption, and turbine temperature, required to achieve a specific power output.

[0040] Some embodiments of the present invention relate to systems for generating foam from aqueous cleaning agents. It has been discovered that differences exist regarding the apparatus and methods for forming acceptable foam with aqueous or non-aqueous agents. Various embodiments of the present invention relate to systems that include a nucleation chamber to which pressurized liquid and further pressurized air are provided.

[0041] It has been found that injecting this foam into the engine inlet with a conventional spray nozzle can reduce the cleaning effectiveness of the foam. Additionally, any piping, tubing, or hose that delivers the foam from the nucleation chamber to the nozzle should be generally smooth and substantially free of turbulence-generating features in the flow path (such as delivery nozzles with sharp turns, abrupt reductions in the flow area of ​​the foam flow path, or areas with excessive convergence, such as convergence that increases the velocity of the foam).

[0042] In various embodiments of the present invention, it is useful to provide a flow path for the generated foam that maintains the foam in a higher energy state and does not dissipate that energy before delivery. Figure 3B shows foam being delivered by one embodiment of the present invention. It can be seen that the nozzle 30 provides a stream of foam that is approximately the same diameter. Little or no convergence is evident in the photograph of Figure 3B, and there is no deviation in the flow stream. Furthermore, ripples or "lumps" in the flow stream of foam are indicative of a low-velocity delivery system, where the disturbance imparted to the foam stream upon impact with the spinner clearly travels upstream toward the nozzle. It can be seen that the amplitude of the "lumps" in the foam flow path is greatest near where the spinner strikes the foam and decreases in size toward the outlet nozzle 30. The foam outlet nozzle 30 is of approximately constant diameter and preferably travels at a velocity of less than about 15 feet per second.

[0043] Various embodiments of the present invention are also aided by introducing pressurized gas (including air, nitrogen, carbon dioxide, or any other gas) into the flow of cleaning liquid. Preferably, the air is pressurized to above about 5 psig and below about 120 psig and supplied by a pump or pressurized reservoir. While some embodiments of the present invention involve the use of an airflow evacuation device that can entrain ambient air, still other embodiments using pressurized air have been found to provide improved results.

[0044] Yet another embodiment of the present invention relates to the commercial application of foam cleaning in aircraft engines. As previously discussed, the mechanism by which foamed cleaning agents provide superior results over non-foamed cleaning agents is currently not well understood. Conversely, many experts in the field of jet engine maintenance initially believe that foamed cleaning agents provide the same disappointing results as non-foamed cleaning agents. Therefore, as the use of foam cleaning agents becomes better understood, the impact of improved foam cleaning on the financial considerations of supporting a fleet of engines will also become better understood. Some of these improvements, such as improvements in operating temperatures, specific fuel consumption, and start-up times, as demonstrated by the tests documented herein, are readily apparent. Yet other effects from the use of foam cleaning agents can further impact the design of other life-limited components within the engine.

[0045] For example, engines are currently designed with parts that have a limited life (such as hours of use, time temperature, number of engine cycles, or other basis), and inspection of these components can be scheduled to coincide with liquid washing of the engine. However, because foam washing restores used engines to a better performance level than liquid washing, the use of foam washing typically increases the amount of time the engine can remain in place on an aircraft. However, the increase in time between foam washings (as compared to the interval between liquid washings) can be long enough to prevent foam washing from occurring simultaneously with inspection of the limited-life components. Under these conditions, it may be financially worthwhile to design the limited-life components for a slightly longer cycle. The increased cost of the limited-life components due to their longer life can be more than offset by the increased amount of time a foam-cleaned engine can remain on the wing.

[0046] In such embodiments, improved cleaning resulting at least in part from foam washing can create a paradigm shift in engine washing, inspection, and maintenance intervals. In some embodiments, the effect of foam washing on engine performance parameters (such as start-up time, temperature at full rated power, specific fuel consumption, carbon emissions, nitrogen oxide emissions, and normal engine operating speeds during cruise and takeoff) can be quantified. This quantification can be performed for a group of engines, but in some cases can be applied across different families. When a particular engine within that family is operated on an aircraft, the aircraft operator notes any changes in operating parameters that can be correlated to improvements achieved by foam washing that particular engine. This information obtained by the aircraft operator is passed to the engine owner (which can be the U.S. government, engine manufacturer, or engine leasing company), who determines when to schedule foam cleaning for that particular engine.

[0047] Various embodiments of the foam cleaning method and apparatus described herein have been found through experimentation to be more effective at removing contaminants from used engines than spray cleaning with a liquid cleaning agent. In some cases, the effluent collected in the turbine after foam cleaning was compared to the effluent collected in the turbine after liquid cleaning, where the liquid cleaning preceded the foam cleaning. In these cases, the foam effluent was found to contain significant amounts of dirt and deposits that were not removed by the liquid cleaning.

[0048] In some engine series, the use of foam cleaning is believed to result in improved combustor liner cleanliness. Combustor liners are well known to contain complex arrangements of cooling holes designed not only to maintain a safe temperature for the liner itself, but also to further reduce gas path temperatures, thereby inhibiting the formation of nitrogen oxides. Various embodiments of the present invention are expected to demonstrate reduced nitrogen oxide emissions in cleaned engines.

[0049] 1-4 depict various views of a washing or cleaning system 20 according to one embodiment of the present invention. While shown and described is a washing system 20 applied to cleaning gas turbine engines, it is understood that various embodiments of the present invention contemplate cleaning any object.

[0050] 1 and 2 schematically represent a system 20 used to clean a jet engine 10. The engine 10 typically includes a cold section including an inlet 11, a fan 12, and one or more compressors 13. Compressed air is provided to a hot section of the engine 10 including a combustor 14, one or more turbines 15, and an exhaust system 16, illustratively including a simple convergent nozzle, a noise-reducing nozzle (as seen in FIG. 6), and a cooled nozzle (such as those used with post-combustion engines and including convergent and divergent sections).

[0051] 2 schematically illustrates a system 20 used to foam clean engine 10. System 20 typically includes a gas supply 26, a water supply 24, and a cleaning agent supply 22, all of which are provided to a foam system 40. Foam system 40 receives these input components and provides an output of foam 28 to a nozzle 30, which provides the foam to inlet 11 of engine 10. However, other embodiments contemplate positioning nozzle 30 so that the foam is first provided to compressor section 13, or in some embodiments, to other components of engine 10. System 20 preferably includes an effluent collector 32 positioned after exhaust 16 of engine 10, thereby collecting therein spent foam, agent, water, and particulate matter removed from engine 10.

[0052] 3A and 3B depict cleaning system 20 in operation. In one embodiment, foaming system 40 is provided within cabinet 42. Cabinet 42 preferably contains various equipment used to form foam 28, including a nucleation chamber (shown and described with reference to FIG. 15), a pump, and various valves and piping. Cabinet 42 preferably contains various flow meters or peristaltic pumps 44, pressure gauges 46, and pressure regulators 48 (described with reference to FIGS. 12-14).

[0053] Figure 3B is a photograph of a nozzle 30 injecting foam 28 into the engine inlet 11. Figure 4 is a close-up photograph of foam 28 according to one embodiment of the present invention.

[0054] 3C and 3D show nozzles 30 in front of the inlet 10 according to other embodiments of the present invention. It can be seen that some embodiments utilize pairs of nozzles that deliver foam to the inlet from approximately the same location and space, except that they are on opposite sides of the engine centerline. Typically, the nozzles in some embodiments have non-atomizing nozzles that provide a stream of foam to ambient conditions. As can be seen in FIGS. 3C and 3D, the cross-sectional area of ​​the nozzle apparatus 30 increases generally from the integral central delivery tube to the pair of side-by-side outlet nozzles, each of which has approximately the same cross-sectional area. Thus, the cross-sectional area as a function of length along the flow path of the apparatus 30 is relatively constant in the central region, but then increases as the central region divides into two side-by-side nozzles.

[0055] Figures 6-11 relate to various tests performed with various embodiments of the present invention. Figure 6 provides a view of a corrugated ambient noise suppression exhaust nozzle 16 both after cleaning with existing procedures and after cleaning performed with embodiments of the present invention. Comparing the left and right photographs, it can be seen that after cleaning performed with one embodiment of the present invention (right photograph), the exhaust nozzle 16 was cleaned beyond the level of cleanliness previously achieved after standard cleaning procedures (left photograph).

[0056] 7 provides a pictorial illustration of the improvement in engine start-up time, including results after a standard wash and after a wash according to one embodiment of the present invention. It can be seen that the standard wash reduced the start-up time of a particular engine by only 3 seconds, from 69 seconds to 66 seconds. However, a subsequent wash of the same engine with the wash system of the present invention resulted in a further reduction in start-up time of approximately 9 seconds, thus demonstrating that a cleaning method according to one embodiment of the present invention can improve the flow dynamics of an engine gas path beyond the improvement achieved by standard washing (such as providing a spray of atomized cleaning fluid into the engine inlet).

[0057] Figures 8-11 show tests and test results performed on a helicopter engine. Figures 8 and 9 show the engine 10 being cleaned with outflow foam 28 exiting the dual exhaust nozzle 16. Figure 10 shows the results of several start-up tests performed on the helicopter engine. It can be seen that the start-up time of the used engine was reduced by approximately 5 percent using existing cleaning technology. However, cleaning that same engine with a cleaning system according to one embodiment of the present invention still provided additional gains and a reduction in start-up time of over 22 percent (compared to the original used engine).

[0058] Figure 11 illustrates the improvement in exhaust gas temperature margin of a helicopter engine operating at full speed before and after cleaning. It can be seen that the use of existing cleaning systems on the engine did not result in a measurable improvement in EGT margin. However, that same engine showed an increase in EGT margin (i.e., ability to run coolers) of over 30°C after being cleaned using a system and method according to one embodiment of the present invention.

[0059] Figures 12A and 12B show, in schematic form, cleaning systems 20 and 120 according to various embodiments of the present invention. Many of the components shown schematically in Figures 12A and 12B (including pressure gauges, flow meters, pressure reducing valves, pumps, check valves, nucleation chambers, and other valves and piping) are preferably housed within cabinet 42, which can be seen in Figures 13, 14, and 15.

[0060] Figures 13A, 13B, and 13C are photographs of the exterior of cabinet 42 of foaming system 40 according to one embodiment of the present invention. Various inlets, shut-off valves, flow meters, pressure gauges, and connections are visible in these photographs. Furthermore, the depictions in Figures 13, 14, and 15 are of the same flow system 40, and the various interconnections visible in Figure 15 can originate from the exterior of the cabinet shown in Figures 13 and 14.

[0061] Figure 14 is an enlarged view of a portion of flow cabinet 42 of Figure 13. Figure 14B shows that in one embodiment, Chemical A is preferably provided at about 0.0265 cubic meters (about 7 gallons) per hour, and Chemical B is provided at about 0.0719 cubic meters (about 19 gallons) per hour. Figure 14C shows that the air flow entering the nucleation chamber was between about 0.368 cubic meters per minute and about 0.396 cubic meters (about 13 to 14 cubic feet) per minute, and the water flow (post-pump) used to form the foam was between about 0.0265 cubic meters and about 0.0303 cubic meters (about 7 to 8 gallons) per minute. Figure 14D shows that the water flow measured before the pump was about 0.0265 cubic meters (about 7 gallons) per minute. The pressure gauge in Figure 14D indicates operating pressures of approximately 18-20 psig for air, water, and foam. These specific settings are illustrative only and should not be construed as limiting. Furthermore, these settings were utilized with the specific example flowing Zok27 Agent A and / or Turco5884 Agent B. Similarly, approved products or combinations of base components (i.e., kerosene, isopropyl alcohol, and petroleum-based solvents) may be utilized in accordance with the engine manual. For reference, qualified product lists or approvals are associated with FAA or Naval Air Systems Command approvals. Such gas path approval reports are directed by the industry-followed MIL-PRF-85704 reference.

[0062] FIG. 15 shows the components and piping housed within cabinet 42 and corresponds to FIGS.

[0063] 16 and 18 illustrate various embodiments of a nucleation chamber X60 according to various embodiments of the present invention. Many of these embodiments include a housing X61 that includes an inlet X62 for a gas, an inlet X63 for one or more liquids, and an outlet X64 that provides a foam output 28 to the nozzle X30. In some embodiments, a gas chamber X66 receives gas under pressure from the inlet X62. The gas chamber X66 is preferably enclosed within the housing X61, and is positioned such that a portion of the gas chamber X66 contacts the fluid from the inlet X63 within the housing X61. Some embodiments include a gas chamber X66 that includes one or more openings or other features X70 that provide fluid communication from the internal passage of the chamber X66 and the fluid within the housing X61.

[0064] The introduction of gas through opening X70 is adapted and configured to form bubbles with the cleaning liquid within nucleation zone X65. Preferably, the bubbles are formed by nucleation of a pre-qualified aerated agent using appropriate placement of high-velocity air jets, diffuser regions, growth spikes, and / or centrifugal shearing of the agent, any of which can be used to form bubbles that are higher energy, short-lived states of the more stable, non-foaming liquid agent. The resulting bubbles are provided to outlet X64 for introduction into the inlet of the device to be cleaned.

[0065] In some embodiments, chamber X60 further includes a cell growth region X74 containing materials or devices that promote the fusion of small foam cells into larger foam cells. In yet other embodiments, nucleation chamber X60 can include a cell structuring region X78 containing materials or devices to improve the uniformity of the foam material. Yet another embodiment of X60 includes a laminar flow region X82 in which the foamed material 28 is less turbulent to increase the longevity of the foam cells and therefore the number of foam cells delivered to the inlet 11 of the product 10 being cleaned.

[0066] Some nucleation chambers X60 include a nucleation zone, a growth region, and a structuring region arranged serially within the foam flow path. In yet other embodiments, these zones and regions are arranged coaxially, with the foam initially forming proximal to the centerline of the flow path. In yet other embodiments, the zones and regions are arranged coaxially, with the foam forming at the periphery of the flow path and the cells growing and becoming progressively structured toward the center of the flow path.

[0067] Some of the nucleation chambers X60 described herein include a nucleation zone, growth region, and structured region arranged within a single plenum. However, it is understood that other embodiments contemplate modular arrangements for the nucleation chambers. For example, the nucleation zone can be a separate component bolted to the structured zone or laminar flow zone. For example, the various regions can be attached to each other by flanges and fasteners, threaded fittings, or the like. Furthermore, the system X20 is described herein as including a single nucleation chamber. However, it is understood that the cleaning system can include multiple nucleation chambers. As one example, multiple chambers can be fed from a manifold providing liquid and gas. This parallel flow arrangement can similarly provide diversified foam output together to a single nozzle X28 or to multiple nozzles arranged in a pattern to optimally match the engine inlet geometry.

[0068] The various cleaning systems X20 discussed herein can include a mixture of liquids (e.g., water, chemical A, and chemical B) provided to the inlet of a nucleation chamber into which a gas is injected to form bubbles from the mixture of liquids. However, the present invention is not so limited and further includes embodiments in which the liquids can be foamed separately. For example, a cleaning system according to another embodiment of the present invention can include a first nucleation chamber for chemical A and a second nucleation chamber for a mixture of chemical B and water. The resulting two bubbles can then be provided to a single nozzle X28 or can be provided to separate nozzles X28.

[0069] The various descriptions that follow relate to various embodiments of nucleation chamber X60, incorporating numerous differences and numerous similarities. It will be understood that each of these is presented by way of example only and is not intended to limit the broad ideas expressed herein. As yet another example, the present invention contemplates an embodiment in which a liquid product is provided at inlet X63 and flows within a flow path surrounded by centrifugal gas chamber X66. In such an embodiment, gas chamber X66 defines an annular flow space and provides gas under pressure to the liquid product flowing within the annulus from inlet X62.

[0070] 18A and 18B show a nucleation chamber 60 according to one embodiment of the present invention. A housing 61 includes a gas inlet 62, a liquid inlet 63, and a foam outlet 64, with a foam-forming passageway disposed between the inlet and outlet. Contained within the housing 61 is a generally cylindrically shaped gas tube 66 that receives gas under pressure from the inlet 62. While the gas chamber 66 is described as a cylindrically shaped tube, other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into a liquid stream such that bubbles result.

[0071] Gas tube 66 is generally coaxially disposed within housing 61 (although coaxial orientation is not required), such that liquid from inlet 63 flows generally around the exterior surface of tube 66. Tube 66 preferably includes a plurality of apertures 70 adapted and configured to channel gas from within tube 66 generally to the bubble-forming passageway within housing 61. As shown in FIG. 18A , apertures 70 are disposed generally along the length of tube 66, preferably around the circumference of tube 66. However, still other embodiments of the present invention contemplate apertures 70 having locations limited to specific selected portions of tube 66, such as toward the inlet, toward the outlet, approximately centrally, or any combination thereof.

[0072] By way of example, nucleation jets 70 are adapted and configured to have a total flow area approximately equal to or less than the cross-sectional flow area of ​​housing 61. By way of example, jets 70 have a bore diameter of about 3.18 mm (1 / 8 inch) to about 1.59 mm (1 / 16 inch).

[0073] Bubbles within the nucleation chamber 60 are initially formed in a nucleation zone 65, which includes the initial mixing of the gas and liquid streams, as discussed above. As the bubbles leave this zone, they flow downstream into a growth region 74 and travel through a corresponding growth material 75. The material 75 is adapted and configured to provide a structured surface area on which individual bubble cells can attach to and combine with other bubble cells to divide into more bubble cells. The material 75 includes a plurality of structures that divide larger, more powerful cells into several smaller cells. In some embodiments, the material 75 is a mesh, preferably formed from a metal material. Plastic materials can also be substituted if the organic material can withstand exposure to the liquid 22 used for cleaning. It is further contemplated by still other embodiments that the material 75 can be a material other than a mesh.

[0074] As the more divided foam cells exit growth region 74, they preferably enter a cell structured region 78 that includes material 79 within the interior foam passages of housing 61. Material 79 of cell structured region 78 is adapted and configured to receive a first varying distribution of foam cell sizes from growth region 74 and provide a second, smaller, narrower distribution of cell sizes to output 64. In some embodiments, structured material 79 includes a mesh formed from a metal, where the cell size of the mesh in region 78 is smaller than the mesh size of growth region 74.

[0075] After the merged (more abundant cells) and structured (improved uniformity) cells exit region 78, they enter a portion of a flow path that may be partially within housing 61 and partially outside housing 61, which is adapted and configured to provide laminar flow of foam 28. Accordingly, the cross-sectional area of ​​laminar flow region 82 is preferably larger than the typical cross-sectional flow area of ​​nucleation region 65, growth region 74, or structured region 78. Flow region 82 promotes laminar flow and discourages turbulence that may otherwise reduce foam quantity or quality. Additionally, the output region of device 60, along with the flow passageway extending to nozzle 30, is generally smooth with a sufficiently gradual turn radius to further promote laminar flow and discourage turbulence.

[0076] 16 illustrates a nucleation chamber 260 according to one embodiment of the present invention. A housing 261 includes a gas inlet 262, a liquid inlet 263, and a foam outlet 264, with a foam-forming passageway disposed between the inlet and outlet. Contained within the cylindrical housing 261 is a generally cylindrical gas tube 266 that receives gas under pressure from the inlet 262. While the gas chamber 266 is illustrated as a cylindrical tube, other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into a liquid stream such that bubbles result.

[0077] Gas tube 266 is disposed generally coaxially within housing 261 (although coaxial orientation is not required), such that liquid from inlet 263 flows generally around the exterior surface of tube 266. Tube 266 preferably includes a plurality of regularly spaced openings 270 adapted and configured to allow gas from within tube 266 to flow generally into the bubble-forming passage within housing 261. As shown in FIG. 16A, openings 270 are disposed generally along the length of tube 266, preferably circumferentially around the circumference of tube 266.

[0078] The nucleation, growth, and cell structuring zones (272, 274, and 278, respectively) are coaxially arranged. Nucleation zone 272 is formed between the outer periphery of tube or pipe 266. The wire mesh material 275 of growth region 274 wraps around the outer periphery of tube 266, best seen in FIG. 16F (where it is shown held in place by three electrical connection strips). Nucleation region 272 is formed between the outer periphery of pipe 266 and the innermost surface of growth material 275. When gas bubbles are emitted from openings 270 and pass through nucleation zone 272, bubbles are formed, and bubble cells pass through one or more generally coaxial layers of mesh material 275. As the larger foam cells exit the material 275 of the growth region 274, they then proceed into an annularly arranged woven metal material 279 comprising a cell structured and homogenized region 278 (as best seen with reference to Figures 16C and 16F). With reference to Figure 16E, it can be seen that the material 279 of the homogenized region 278 in one embodiment tapers toward the centerline of the nucleation chamber 260. The foam cells are formed, increased in size, and homogenized by the mixing of liquid and gas in the manner previously discussed.

[0079] After the fused (grown) and structured (improved uniformity) cells exit region 278, they enter a portion of a flow path that may be partially within housing 261 and partially outside housing 261, which flow path is adapted and configured to promote laminar flow of foam 228 (best seen in FIGS. 16E, 15A, and 15B). It can be seen that the outer diameter of the flow path from outlet 264 to outlet 228-1 on cabinet 42 (best seen in FIGS. 13B and 15A) is approximately the same size as the outer diameter of nucleation chamber 260. However, the cross-section of nucleation chamber 260 (visible in FIGS. 16A and 16F) has a smaller flow area than the cross-sectional flow area of ​​the piping downstream of outlet 264 (best seen in FIG. 15A), and the cross-sectional flow area of ​​the foam flow path within chamber 260 is partially blocked by materials 275 and 279. The flow region 282 (as best seen in Figures 15A and 15B) encourages laminar flow and discourages turbulence that may otherwise reduce the quantity or quality of the foam. Additionally, the output region of the device 260 is generally smooth, along with the flow path extending to the nozzle 230, with a sufficiently gradual turn radius to further encourage laminar flow and discourage turbulence.

[0080] 18C illustrates a nucleation chamber 360 according to one embodiment of the present invention. A housing 361 includes a gas inlet 362, a liquid inlet 363, and a foam outlet 364, with a foam-forming passageway disposed between the inlet and outlet. Contained within the housing 361 is a generally cylindrically shaped gas tube 366 that receives gas under pressure from the inlet 362. While the gas chamber 366 is illustrated as a cylindrically shaped tube, other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into a liquid stream such that bubbles result.

[0081] Gas tube 366 is disposed generally coaxially within housing 361 (although coaxial orientation is not required), such that liquid from inlet 363 flows generally around the exterior of tube 366. Tube 366 preferably includes a plurality of openings 370 adapted and configured to allow gas from within tube 366 to flow generally into the bubble-forming passage within housing 361. As shown in FIG. 18C, openings 370 are disposed generally along the length of tube 366, preferably circumferentially around the circumference of tube 366.

[0082] Nucleation zone 365 includes jets or perforations 370 arranged in multiple sub-zones, with jets in such sub-zones 372 injecting gas into the flowing liquid at various angles of attack. A first nucleation zone 372a is positioned upstream of a second, intermediate nucleation zone 372b, which is followed by a third nucleation zone 372c (each of which is positioned and spaced apart along the length of gas chamber 366). As shown in FIG. 18C, zone 372b overlaps both zones 372a and 372c, although other embodiments of the invention contemplate greater or lesser overlap, including no overlap.

[0083] The jets or perforations 370a in zone 372a are preferably adapted and configured to have an angle of attack generally opposite (or counter to) the main liquid flow (flowing from left to right as viewed in FIG. 18C ). By way of example, the centerlines of these jets 370a are approximately 30-40 degrees from a line extending perpendicular to the centerline of the foam flow path in chamber 360 (i.e., form a 60-50 degree angle with the centerline). Thus, air exiting perforations 370a in zone 372a imparts energy to the surrounding liquid flow, and this energy acts to decelerate the liquid (i.e., the velocity vector of the gas exiting nozzles 370a has an opposite component to the velocity vector of the liquid flowing from left to right in chamber 360, FIG. 18C ).

[0084] Nucleation jets 370 in zone 372b are angled to impart a rotating vortex to the fluid in the foam channel. In one embodiment, nucleation jets 370b are angled approximately 30-40 degrees from perpendicular to the channel centerline in a direction that imparts a tornado-like rotation within nucleation chamber 360.

[0085] The third nucleation zone 372c includes multiple jets 370c angled at approximately 30-40 degrees in a direction that pushes the liquid axially in the general direction of flow within the foam flow path (i.e., left to right, and generally opposite the angular orientation of jets 370a).

[0086] It is further understood that the perforations or nucleation jets 372 within zone 370 can have the attack angles described hereinabove, either entirely among all jets or only partially among some of the jets. Other embodiments of the invention contemplate zones 372a, 372b, and 372c in which only a portion of each jet 370a, 370b, or 370c is angled as described hereinabove, while the remainder of each jet 370a, 370b, or 370c is oriented differently. Furthermore, while what has been shown and described thus far is a first zone A having an angle of attack opposite that of the fluid flow, followed by a second zone B having jets with an angle of attack oriented to impart vortices, and then a third zone C having jets with an angle of attack oriented to push bubbles toward an outlet, it is understood that various embodiments of the invention contemplate still other arrangements of angled jets. By way of example, still other embodiments contemplate a fluid vortex region located at the beginning or end of a nucleation zone. As a further example, yet another embodiment contemplates a counter-flow region (previously described as zone 372a) positioned toward the most distal end of the nucleation zone (i.e., oriented closer toward growth region 374). In yet another embodiment, there is a nucleation zone that comprises fewer than all three of zones A, B, and C, including those embodiments having holes positioned with only one of the characteristics of zones A, B, and C described above.

[0087] 18D shows a nucleation chamber 460 according to one embodiment of the present invention. A housing 461 includes a gas inlet 462, a liquid inlet 463, and a foam outlet 464, with a foam-forming passageway disposed between the inlet and outlet. Contained within the housing 461 is a generally cylindrically shaped gas tube 466 that receives gas under pressure from the inlet 462. While the gas chamber 466 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into a liquid stream such that bubbles result.

[0088] Gas tube 466 is generally coaxially disposed within housing 461 (although coaxial orientation is not required), such that liquid from inlet 463 flows generally around the exterior surface of tube 466. Tube 466 preferably includes a plurality of apertures 470 adapted and configured to channel gas from within tube 466 generally to a bubble-forming passageway within housing 461. As shown in FIG. 18D , apertures 470 are generally randomly disposed along the length of tube 466, preferably circumferentially around the circumference of tube 466. However, still other embodiments of the present invention contemplate apertures 470 having locations limited to specific selected portions of tube 466, such as toward the inlet, toward the outlet, approximately in the center, or any combination thereof.

[0089] 18E shows a nucleation chamber 560 according to one embodiment of the present invention. Housing 561 includes gas inlet 562, liquid inlet 563, and foam outlet 564, with a foam-forming passageway disposed between the inlet and outlet. Contained within housing 561 is a gas chamber or plenum 566 that receives gas under pressure from inlet 562. While gas chamber 566 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into a liquid stream such that bubbles result.

[0090] Gas tube 566 is generally coaxially disposed within housing 561 (although coaxial orientation is not required), such that liquid from inlet 563 flows generally around the exterior surface of tube 566. Tube 566 preferably includes a plurality of apertures 570 adapted and configured to channel gas from within tube 566 generally into the bubble-forming passage within housing 561. As shown in FIG. 18E , apertures 570 are disposed generally along the length of tube 566, preferably around the circumference of tube 566. However, still other embodiments of the present invention contemplate apertures 570 having locations limited to specific selected portions of tube 566, such as toward the inlet, toward the outlet, approximately in the center, or any combination thereof.

[0091] The openings in zones 572a, 572b, and 572c are generally positioned as previously described with respect to nucleation chamber 560. Figure 18E includes an inset showing a single nucleation jet 570a having an angle of attack 571a. The velocity vector of gas outlet jet 570a includes a velocity component that is opposite (i.e., upstream) to the general flow direction of the foam flow path from inlets 562 and 563 to outlet 564.

[0092] 18F illustrates a nucleation chamber 660 according to one embodiment of the present invention. A housing 661 includes a gas inlet 662, a liquid inlet 663, and a foam outlet 664, with a foam-forming passageway disposed between the inlet and outlet. Contained within the housing 661 is a generally cylindrically shaped gas tube 666 that receives gas under pressure from the inlet 662. While the gas chamber 666 is illustrated as a cylindrically shaped tube, other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into a liquid stream such that bubbles result.

[0093] Gas tube 666 is generally coaxially disposed within housing 661 (although coaxial orientation is not required), such that liquid from inlet 663 flows generally around the exterior surface of tube 666. Tube 666 preferably includes a plurality of apertures 670 adapted and configured to channel gas from within tube 666 generally to the bubble-forming passageway within housing 661. As shown in FIG. 18F , apertures 670 are disposed generally along the length of tube 666, preferably around the circumference of tube 666. However, still other embodiments of the present invention contemplate apertures 670 having locations limited to specific selected portions of tube 666, such as toward the inlet, toward the outlet, approximately in the center, or any combination thereof.

[0094] Bubbles in nucleation chamber 660 are initially formed in nucleation zone 665, which includes the initial mixing of gas and liquid streams as discussed above. As the bubbles leave this zone, they flow downstream into growth region 674 and travel over and around ultrasonic transducer 675. In one embodiment, transducer 675 is a rod (as shown), although it is understood that in yet other embodiments, the ultrasonic transducer may be of any shape adapted and configured to provide ultrasonic excitation to bubbles exiting nucleation zone 665. For example, yet other embodiments of the present invention contemplate transducers having a generally cylindrical shape such that bubbles flow through the inner diameter of the cylinder; in some embodiments where the transducer is smaller than the inner diameter of flow channel 661, the bubbles also travel across the outer diameter of the transducer. Furthermore, it is understood that while one embodiment includes a transducer excited at ultrasonic frequencies, yet other embodiments contemplate sensors that vibrate at any frequency, including audio and subsonic frequencies, to impart vibrations to nucleated bubbles.

[0095] Referring to the small inset in FIG. 18F, the transducer 675 is preferably excited by an external electron source. In one example, the electron source provides an oscillating output voltage that excites a piezoelectric element within the transducer 675. The use of a vibrating transducer has been found to be effective in converting a substantial amount of provided liquid into foam. Various embodiments of the present invention contemplate exciting vibrations within the transducer 675 with any type of vibration input, including one or more single frequencies, a frequency sweep over a range, or a random frequency input over a range of frequencies. In one test, a transducer provided by Sharpertek was excited at frequencies exceeding 25 kHz. While a generally cylindrical transducer rod is shown, other embodiments contemplate vibration transducers of any shape, including side-mounted transducers, i.e., transducers that can be used in rectangular chambers so that liquid and gas within the chamber flow near the transducer for improved effectiveness. Additionally, while electronic excitation of the transducer 675 is contemplated in some embodiments, it is understood that in other embodiments the transducer 675 can be excited by other mechanical means, including by hydraulic or pneumatic input. Additionally, another embodiment contemplates the use of a vibration table within the cabinet 42 to physically shake the nucleation chamber. In such an embodiment, the inlet and outlet of the nucleation chamber are coupled to other piping within the cabinet by flexible fittings.

[0096] As the larger foam cells exit growth region 674, they enter cell structured region 678, which preferably includes material 679 within the interior foam passages of housing 661. Material 679 in cell structured region 678 is adapted and configured to receive a first, larger distribution of foam cell sizes from region 674 and provide a second, smaller, narrower distribution of cell sizes to output 664. In some embodiments, structured material 679 includes a mesh.

[0097] 18G shows a nucleation chamber 760 according to one embodiment of the present invention. A housing 761 includes a gas inlet 762, a liquid inlet 763, and a foam outlet 764, with a foam-forming passageway disposed between the inlet and outlet. Contained within the housing 761 is a generally cylindrically shaped gas tube 766 that receives gas under pressure from the inlet 762. While the gas chamber 766 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into a liquid stream such that bubbles result.

[0098] Gas tube 766 is disposed approximately coaxially within housing 761 (although coaxial orientation is not required), such that liquid from inlet 763 flows generally around the exterior of tube 766. Tube 766 preferably includes multiple nucleation devices 770, each containing multiple small holes for the passage of air. As shown in the inset of FIG. 18G, in one embodiment, device 770 is a porous metal filter muffler, such as those manufactured by Alwitco of North Royalton, Ohio. These devices include a porous metal member attached to a threaded member. Air is provided from the threaded member to a porous material, which in one embodiment contains multiple holes surrounding the periphery and ends of the porous member, the holes ranging anywhere from about 10 to 100 microns in diameter. Still other embodiments contemplate the use of porous metal breather-vent filters, such as those provided by Alwitco. Yet another embodiment contemplates a device 770 that includes gas outlet passages similar to those of Alwitco's micro- and mini-muff-like mufflers.

[0099] More broadly, device 770 includes an internal flow path that receives gas under pressure from within chamber 766. The end of device 770 includes a plurality of holes (achieved, for example, by using porous metal, or by drilling, stamping, chemical etching, photoetching, electro-discharge machining, etc.) in a pattern (random or ordered) such that gas from the internal passage of device 770 flows into the surrounding liquid mixture and forms bubbles. As best seen in FIG. 18G , in some embodiments, the porous end of device 770 is cylindrical and extends into the liquid flow path, while in yet other embodiments, the porous end is generally flat, and in still other embodiments, it can be any shape. In some embodiments, device 770 has directionally oriented porosity such that the protruding end of the device is substantially non-porous on the upstream side and porous on the downstream side of the device. In such embodiments, bubbles form immediately behind the liquid as it travels over the protruding body of device 770. As shown in FIG. 18G, in some embodiments, there are multiple devices 770 positioned along the length and around the circumference of (or otherwise extending from) the gas chamber 766.

[0100] Yet another embodiment contemplates a gas chamber 766 fabricated from a porous metal, such as the porous metals discussed above. In such embodiments, gas escapes from the chamber and enters the liquid flow path along the entire length of the porous structure. Additionally, some embodiments contemplate a gas chamber constructed from a material that includes a plurality of holes (formed by drilling, stamping, chemical etching, photoetching, electrical discharge machining, etc.).

[0101] 18H shows a nucleation chamber 860 according to one embodiment of the present invention. Housing 861 includes gas inlet 862, liquid inlet 863, and foam outlet 864, with a foam-forming passageway disposed between the inlet and outlet. Contained within housing 861 is a generally cylindrically shaped gas tube 866 that receives gas under pressure from inlet 862. While gas chamber 866 is illustrated as a cylindrically shaped tube, yet other embodiments of the present invention contemplate an internal gas chamber of any size and shape adapted and configured to provide a flow of gas into a liquid stream such that bubbles result.

[0102] Gas tube 866 is disposed generally coaxially within housing 861 (although coaxial orientation is not required), so that liquid from inlet 863 flows generally around the exterior of tube 866. Tube 866 preferably contains a plurality of devices 870 similar to nucleation jets 770 previously described.

[0103] Bubbles within nucleation chamber 860 are initially formed in nucleation zone 872, which includes the initial mixing of gas and liquid streams as discussed above. As the bubbles leave this zone, they flow downstream into growth region 874 and travel over corresponding growth material 875. In some embodiments, material 875 is a mesh, preferably formed from a metallic material. Plastic materials can also be substituted, provided that organic materials can withstand exposure to liquid 822 used for cleaning. It is further contemplated by still other embodiments that material 875 can be materials other than a mesh.

[0104] As the larger foam cells exit growth region 874, they preferably enter cell structured region 878, which includes material 879 within the interior foam passages of housing 861. Material 879 of cell structured region 878 is adapted and configured to receive a first, larger distribution of foam cell sizes from region 874 and provide a second, smaller, narrower distribution of cell sizes to output 864. In some embodiments, structured material 879 includes a mesh formed from metal, where the cell size of the mesh in region 878 is smaller than the mesh size of growth region 874. In one test, device 860 successfully converted a large volume of liquid into foam.

[0105] 18I shows a nucleation chamber 960 according to one embodiment of the present invention. A housing 961 includes a gas inlet 962, a liquid inlet 963, and a foam outlet 964, with a foam-forming passageway disposed between the inlet and outlet. Contained within the housing 961 is a generally cylindrical chamber 966 that receives gas under pressure from the inlet 962.

[0106] A gas chamber 966 is disposed generally within the foam flow path of chamber 960, such that liquid from inlet 963 flows generally around the exterior of chamber 966. In one embodiment, and as shown in the inset of FIG. 18I, chamber 966 includes multiple radiator-like structures within the foam flow path. Each structure includes one or more main supply pipes 966.1 that provide gas from inlet 962 to one or more crossover tubes 966.2 that extend across the foam flow path. Each of these crossover tubes 966.2 includes multiple nucleation jets 970 through which gas passes into the flowing fluid. In one embodiment, crossover tubes 966.2 are generally in contact with multiple fin-like members 975 that extend generally across some or all of the crossover tubes 966.2. Thus, this chamber 966 combines a nucleation zone 972 and each of growth and / or homogenization regions 974 and 978 into a single device. As a result, liquid enters the upstream side of device 966 and bubbles exit the downstream side of device 966. In one embodiment, device 966 is similar to a computer chip cooling radiator and heat sink.

[0107] 18J shows a nucleation chamber 1060 according to one embodiment of the present invention. Housing 1061 includes a gas inlet 1062, a liquid inlet 1063, and a foam outlet 1064, with the foam formation passageway disposed between the inlet and outlet. Contained within housing 1061 is a gas chamber 1066 that receives gas under pressure from inlet 1062.

[0108] In one embodiment, the chamber 1066 includes a supply plenum 1066.1 in fluid communication with a plurality of longitudinally extending tubes 1066.2. Preferably, each of the tubes 1066.1 and 1066.2 extends into the flow path of the nucleation chamber 1060 and further incorporates a plurality of nucleation jets 1070. As seen in FIG. 18J, in some embodiments, the tubes 1066.2 are longitudinally oriented, such that liquid flows generally along the length of the tubes 1066.2. However, in other embodiments, the tubes 1066.2 can also be orthogonally oriented in a manner similar to the tubes 966.2 described with respect to the nucleation chamber 960.

[0109] FIG. 18K illustrates a nucleation chamber 1160 according to one embodiment of the present invention. The housing 1161 includes a gas inlet 1162, a liquid inlet 1163, and a foam outlet 1164, with a foam-forming passageway disposed between the inlet and outlet. Contained within the housing 1161 is a nucleation zone 1172, which includes both a plenum 1166 for releasing gas into the foam flow path and a motorized mixing device including an impeller 1186 driven by a motor 1184. In one embodiment, the impeller 1186 is coupled to a shaft and includes one or more curved agitation paddles similar to paint agitation devices. Gas from the outlet tube of the chamber 1166 is provided upstream of the agitation paddles. Foam formed in this manner has been found to exhibit acceptable foam cell size, although it varies widely. Yet another embodiment includes a cell-structured region 1178 (not shown) disposed downstream of the nucleation region 1172. Yet another example of an agitating member is shown in the inset of FIG. 18K, including devices 1186-1 and 1186-2. In one application, nucleation device 1186-1 resembles a coiled spring impeller, similar to those sold by McMaster Carr. In yet another embodiment, device 1186-2 is similar in structure to the impeller of a hair dryer. In some embodiments, the foam prepared in chamber 1160 is preferably created with liquid 1163 provided at a relatively low flow rate.

[0110] Figures 18L, 18M, 18N, 18O, 18P, 18Q, and 18R illustrate a nucleation chamber 1260 according to another embodiment of the present invention. These figures illustrate various angular and other geometric relationships between the various components of the nucleation device 1260. Figure 18O illustrates that the first zone of nucleation 1272a can include a jet with a negative angle of attack, meaning that there can be a velocity component of the air exiting the gas plenum that is opposite to the overall flow direction of the liquid flowing through the nucleation device. Figures 18P and 18Q illustrate that the downstream nucleation zones 1272b and 1272c can include an air injection angle that includes a velocity component in the same direction as the liquid flow (which has already passed through the first zone 1272a and is partially formed). Figure 18R further illustrates the nucleation jet 1270 oriented to impart a vortex to the foamed mixture (i.e., rotation about the central axis of the nucleation device). It is further understood that various nucleation jets can have combinations of vortex angles shown in FIG. 18R, with any of the alpha, beta, or rho angles shown in FIG. 18O, FIG. 18P, or FIG. 18Q, respectively.

[0111] In some embodiments of the present invention, the total flow area of ​​all nucleation jets ranges from about 50 percent of the cross-sectional flow area N of the gas plenum to about three times the total cross-sectional flow area N of the glass plenum. To achieve this ratio of total nucleation jet area to total plenum cross-sectional area, the length N can be adjusted accordingly. In yet other embodiments, the ratio of the cross-sectional area O of the inner diameter of the nucleation device to the area N of the gas plenum should be less than about 5.

[0112] FIG. 19 provides pictorial illustrations of aircraft engine cleaning according to various embodiments of the present invention. FIG. 19A shows a vehicle 21 parked between the wing and engine of a DC-9 family aircraft. FIGS. 19B and 19C show a vehicle 21 using a washing system 20 to clean the right engine of a DC-10 type aircraft. The vehicle 21 includes the washing system 20. A nozzle 30 is supported from an extendable boom 23 near the inlet 11 of the fuselage-mounted engine 10. An effluent collector 32 is positioned near the exhaust 16 of the engine 10. In one embodiment, the collector 32 includes a housing 33 coupled to a retention member 34. In some embodiments, the retention member 34 is coupled to the vehicle 21 (or alternatively to the tarmac or other suitable restraint) to maintain the location of the collector 32 behind the engine 10 during the cleaning process. In some embodiments, the housing 33 is inflatable with air, in a manner similar to large outdoor play equipment. In such an embodiment, the vehicle 21 further includes a blower for providing air under pressure to the housing 33 .

[0113] Foam from the nozzle 20 supported by the boom 23 is preferably provided into the inlet 11 of the engine 10 as the engine 10 is rotated by its starter. Foam 28 is injected into the inlet 11 as the engine 10 is rotated on its starter. In some embodiments, normal operation of the starter results in a maximum engine free-running (i.e., non-operating) speed, which is typically less than the engine idling (i.e., operating) speed. However, in some embodiments, methods utilizing the system 20 preferably include rotating the engine at a rotational speed below the normal free-running speed. At such low speeds, cooler zone components of the engine 10 are less likely to reduce the quality or quantity of foam before it is provided to the hotter zones of the engine. In one embodiment, the preferred rotational speed during cleaning is less than about 25 to about 75 percent of the free-running speed.

[0114] 2-1A and 2-1B depict various views of a washing or cleaning system 20 according to one embodiment of the present invention. Shown is a washing system 20 adapted for cleaning a gas turbine engine, but it is understood that various embodiments of the present invention contemplate cleaning any object. The washing system 20 may be incorporated inside a vehicle 21. The vehicle 21 may also take the form of a trailer, compact car, or dolly that can be moved like the vehicle 21 to a desired location with varying capacities.

[0115] FIG. 2-1A pictorially depicts a rear-side view of an engine 10 being cleaned on the wing of an aircraft 90 within an airfield. A vehicle 21 includes a washing system 20 for supplying a cleaning foam product to the engine 10 via a hose 33 elevated to the engine 10 by a support 34. It is also contemplated that the vehicle 21 may supply the support 34 or even a boom 23 (see FIG. 2-2 below).

[0116] 2-1B pictorially depicts a front view of a washing system 20 used to clean a jet engine 10. The system 20 typically includes a gas supply 26 (not shown), a water supply 24, a cleaning agent supply 22, and an electrical supply (not shown), all of which are provided to a foaming system 40. The foaming system 40 receives these input components and provides an output (not shown) of foam 28 to the inlet 11 of the engine 10 via a nozzle 30.

[0117] 2-2, 2-3, and 2-4 pictorially represent various embodiments of the positioning of the effluent collector 32 and vehicle 21. The effluent collector 32 is designed to collect foam and effluent for post-treatment, reuse (treatment unit 80, see below, FIG. 2-7), or disposal.

[0118] FIG. 2-2 pictorially illustrates the effluent collector 32. The effluent collector 32 can be inflated similarly to outdoor play equipment or similarly to an aircraft emergency ramp or life raft. In one embodiment, the effluent collector 32 provides structural support to contain foam, liquid, and solid particles in a manner that is safe and gentle for the aircraft. Additionally, the vehicle 21 can include a boom 23 that elevates the nozzle 30 (even larger on the nozzle 30 in FIG. 2-8). The boom 23 allows the nozzle 30 to be positioned for foam injection into the engine 10. The boom 23 can have a combination or range of degrees of freedom in space in addition to, but not limited to, extension, rotation, and / or angle.

[0119] FIG. 2-3 pictorially depicts an effluent collector 32 (similar to FIG. 2-2) on a sizable jet engine 10. The vehicle 21 can be positioned in front of the engine 10, but is not limited to this one specific example. For example, the jet engine 10 at the top rear of an aircraft 90 is high enough to allow the vehicle 21 and boom 23 to reach the entrance (as in FIG. 8). In such a contemplated scenario, the effluent collector 32 can be elevated by another vehicle 21 with a boom 23 or by a support 34 (as in FIG. 2-1).

[0120] 2-4 pictorially represent one embodiment of the effluent collector 32. The collector 32 can be a floor mat with containment walls 37. In one example, the containment walls 37 are designed to be elevated by brackets or are designed to be inflatable. The effluent collector 32 can be of various sizes and dimensions to contain one or many engines 10 during the cleaning process.

[0121] Figures 2-5 are schematic and artist's photographs of an aircraft engine 10 being cleaned using a system according to one embodiment of the present invention. The engine 10 is mounted according to the design of the aircraft 90; here, the illustration shows a bi-rotor helicopter (Bell) with the engine 10 mounted horizontally toward the rear, although another design has the engine 10 mounted on the side of the wing and pivoting between vertical and horizontal (V22 Osprey). The vehicle 21 demonstrated in this photograph incorporates a trailer. The orientation of the engine 10 on the V22 aircraft is vertical, with a hose 33 directing the foam cleaning product toward the nozzle 30 at the engine inlet 11. Cleaning or washing the engine 10 in this manner allows engine specifications (more detailed in Figures 2-10) to allow core components of the engine 10 to alternate between rotating, stationary, or both, if possible. It is contemplated that the cleaning foam product can trickle down without agitation / rotation. The effluent then exits the bottom of the engine 10 and is captured (similar to Figures 2-4) or directed into a sewer.

[0122] 2-7 are schematic diagrams of a cleaning process / method according to one embodiment of the present invention. As demonstrated in all previous figures, the apparatus and method of the present invention enable versatility in the art. The schematic diagrams show a methodology of process steps for cleaning an engine 10. For illustrative purposes, the process begins in a vehicle 21 including a washing system 20. The washing system provides a foam cleaning product to clean the engine 10, where dirt, contaminants, liquids, and foam, i.e., effluent, are released from the engine 10. Because site conditions and regulations vary (i.e., aircraft, private property, or military zones), the method and present design contemplate modular flexibility built into the vehicle 21. For example, the effluent has three possible routes it can take: Path A, B, or C. In the first path, Path A, the effluent can proceed directly to a sewer or to the ground. The effluent collector 32 system then allows the foam, liquid, and contaminated materials to be recycled and / or treated by a treatment unit 80, as indicated by paths B or C. Vehicle 21 can house processing unit 80 as shown in path B, while in path C processing unit 80 can be handled separately from vehicle 21. Processing unit 80 can be a pre-built module similar to those sold by AXEON Water Technologies.

[0123] 2-8A and 2-8B are similar schematic diagrams of an engine illustrating a foam injection system according to one embodiment of the present invention. This schematic diagram shows an enlarged front view of the engine 10 with the fan inlet 11 and compressor area. The two figures are presented to enhance this perspective, particularly the nozzle 30 associated with the engine 10. The nozzle 30 can be multiple nozzles and / or a positional, angular, and / or rotary articulating nozzle. For example, point A in both figures illustrates an articulating nozzle (i.e., a robot or monitor sold by Task Force Tips, a remote-controlled monitor Y2-E11A) with a vertical tube (not limited in size) through which the cleaning foam product can reach and be targeted to the compressor inlet 11 of the engine 10. Similarly, point B in both figures illustrates an articulating nozzle with a "Y"-shaped nozzle outlet (although not limited in design) positioned along the axis of rotation of the engine 10 core, where the nozzle 30 can rotate axially along the compressor inlet 11 zone.

[0124] FIG. 2-9A is a schematic diagram of an engine interior cutaway showing a foam connection system 41 according to one embodiment of the present invention. The engine 10 typically includes a cold section including an inlet 11, a fan 12 (not shown), and one or more compressors 13. Compressed air is provided to the hot section of the engine 10, including a combustor 14, one or more turbines 15, and an exhaust system 16. Because different engines have variations in wear and tear due to contaminating the engine 10, manufacturers have specialized tubes 42, connections, or passages designed for water cleaning procedures. The present invention illustrates an improvement over foam cleaning systems, as shown in FIG. 2-5, where nozzles 30 or hoses 33 can again be directly connected to one or many of the foam connection points 41 (dashed lines) to target specific, some, or all engine sections.

[0125] As an example, some compressor sections are known to include one or more manifolds or tubes that carry compressed air, such as to provide bleed air to an aircraft or to provide relatively cool compressed air for cooling hot engine sections. In some embodiments, cleaning foam is provided to the engine through these manifolds or tubes. This foam can be provided while the engine is rotating or when the engine is stationary. Furthermore, engine hot sections are known to include tubes or manifolds that receive cooler compressed air for the purpose of cooling the hot sections, and blanked-off ports used for boroscope inspection or other purposes. Yet other embodiments of the present invention contemplate introducing foam into such tubes and ports in stationary or rotating engines.

[0126] 2-9B are schematic cutaway views of an engine with internal and external components illustrating a foam connection system according to one embodiment of the present invention. Similar to FIGS. 2-9A, the cutaway view of engine 10 includes inlet 11, fan 12, compressor 13, combustor 14, turbine 15, and exhaust 16 regions. Regardless of existing or future engine manufacturing engineering modifications, tubes 43, passages, and connections can be used to deliver foam for cleaning regions of engine 10. Referring to FIG. 2-1B, hose 33 is shown adapted to connect to nozzle 30; however, hose 33 may alternatively connect directly to one or more of connections 41 on engine 10.

[0127] 2-10 are graphs of an engine cleaning rotation cycle prescription according to one embodiment / method of the present invention. As demonstrated in the most recent figures, the engine 10 can be mounted in numerous configurations (i.e., horizontal, vertical), and engines can come in numerous shapes and sizes. With this in mind, the foam cleaning procedure can operate more effectively at a specified engine 10 core speed (compressor 13 area and turbine 15 area). By way of example, this graph has three types of core speeds (from the compressor 13 to the turbine 15 linked by three individual shafts), shown as N1, N2, and N3. The Y-axis is the maximum allowable rotational speed (actual values ​​not shown, scale is for illustrative purposes only). The X-axis is time (not to scale, for example only). The purpose of the engine cleaning prescription is to rotate and agitate the foam that has overflowed into the gas path inside the engine 10. The foam contacts, scrapes, and removes contaminants. The foam has different fluid dynamic properties at different rotational (agitation) speeds. Thus, cleaning effects can be achieved by cycling the engine 10 over a range of speeds. The figure shows that the engine 10 is cranked three times (three cycles), but is not limited to this frequency. By evaluating the first cycle, it is clear that N1, N2, and N3 behave according to inertial quantities. At zero, where N1, N2, and N3 are zero, when the engine is cranked one unit, N1, N2, and N3 reach ceilings of approximately 10.5%, 8.5%, and 5.8%, respectively. The overflowing foam product inside the engine 10 causes N3 to stop more quickly due to hydrodynamic friction, while N1 can maintain rotation for a longer period in comparison. While cycling once or multiple times in a given cycle is preferred, the engine 10 can also be cleaned without rotation by injecting and overflowing the gas path as discussed in Figures 2-5. The foam temperature is useful for determining the frequency and amplitude of the cycling regime. The vehicle 21 can accommodate a heater 38 to regulate and positively affect the cleaning regimen.

[0128] Figures 2-11 are graphical illustrations of one method of the present invention for engine monitoring and benefit quantification. The positive impacts and benefits of properly cleaning the engine 10 can be further quantified in the present invention. Diagnostic or telemetry tools are used to obtain financial, operational, maintenance, and environmental benefits (i.e., carbon credits, on-wing time, fuel savings, etc.). Data analysis tools are scientific methods for enhancing the life and safety of the engine 10. As shown in Figures 2-11, one embodiment of the present invention includes a method. For example, the engine 10 in an aircraft or boat transmits information to a data center. The engine operator or manufacturer then requests the foam engine cleaning method via computer automation, either separately or with a trained professional. When the foam cleaning method is implemented in conjunction with this monitoring method, performance recovery metrics can log improvements. These quantified improvements can be collected in terms of financial goals, carbon credits, engine life extension, and / or safety.

[0129] Figures 2-12 show various embodiments of a portable effluent collector according to one embodiment of the present invention. The effluent collector includes a trailer 232.1 having a plurality of wheels supporting it from the ground and preferably also including a trailer hitch for towing by another vehicle. The trailer includes a cargo compartment that can be adapted and configured to support and contain foam effluent during the engine cleaning process. As shown in these figures, the cargo compartment is lined with a waterproof, watertight flexible sheet made of plastic, thereby forming a collection pool 232.2 that is generally supported by the wheels.

[0130] The trailer preferably includes a plurality of collection devices that can be conveniently folded into a compact configuration for transport and that can also be extended and supported in an upright position for collection of foam during the cleaning process.

[0131] FIG. 2-12 shows the trailer and collection device in an extended position suitable for collecting foam during the cleaning process. The exhaust collector 232.3 is formed by a waterproof, watertight flexible sheet separated by a pair of spaced ribs 232.34. Support ribs are located on either side of the trailer, each pivotally connected to the forward end of the trailer 232.1. Preferably, the sheet is large enough to fit loosely over the ribs so that, in a vertically supported position, the sheet forms a housing 232.31 having an inlet 232.34 for collection of foam exiting the engine exhaust. The housing 232.31 provides a gravity-assisted flow path from the inlet to a drain located proximal to the pool 232.2. Any foam received at the inlet flows downward within the housing and through the drain into the pool. A pair of vertical supports 232.33 are provided on either side of the housing. Each vertical support connects at one end to the side of the trailer and at another end to a corresponding rib. The ribs and corresponding vertical supports lock together in the extended position (as shown in Figures 2-12) to maintain the chassis in an upright position. When the ribs and vertical supports disengage, the ribs can be folded toward the rear of the trailer and the vertical supports can be folded toward the front of the trailer, or can be removed for transport purposes.

[0132] The aft end of trailer 232.1 includes collector 232.4 adapted and configured to capture runoff from the inlet of the engine being washed and, when the nacelle doors are open, from underneath the engine. Collector 232.4 extends from the forward end of trailer 232.2 and, when supported by vertical supports 232.43, angles upward toward the inlet of the engine being washed. Any foam exiting the engine inlet or exiting the engine nacelle falls onto a drainage channel formed by the support of sheet 232.41 between pairs of spaced, substantially parallel support ribs 232.42. Each of these ribs is pivotally connected to the forward end of the trailer. Each of vertical supports 232.43 is attached to a rib and contacts the ground. Any foam falling onto the drainage channel of concave sheet 232.41 moves by gravity toward pool 232.2.

[0133] Various aspects of different embodiments of the present invention are presented in paragraphs X1, X2, X3, X4, X5, X6 and X7 as follows:

[0134] X1. One aspect of the present invention relates to an apparatus for foaming a water-soluble liquid cleaning agent, the apparatus comprising a housing having a plurality of sequentially arranged foam manipulation sections or regions, the housing having a gas inlet, a water-soluble cleaning agent liquid inlet, and a foam outlet, one section or section including a pressurized gas injection device having a plurality of openings, the interior of the housing forming a mixing region that receives liquid from the liquid inlet and gas released from the openings to form foam having a first average cell size and a first range of cell sizes, another foam manipulation section receiving cells having a first distribution range and a first average size and flowing them over a cell attachment and growth member that provides a surface area for cell attachment and fusion to form foam having a second, larger average cell size, and yet another foam manipulation section or section receiving foam having a first range of cell sizes and flowing the foam through a foam structuring member configured to reduce the range of foam sizes and provide a more uniform foam output.

[0135] X2. Another aspect of the present invention relates to a method for foaming a liquid, comprising mixing a liquid and a pressurized gas to form a foam, flowing the foam through a member to increase the size of the cells, and then flowing the foam through a plurality of openings or a grid to reduce the size of the cells.

[0136] X3. Yet another aspect of the present invention relates to a system for providing an air-foamed, water-soluble liquid cleaning agent, the system comprising: an air pump providing air at a pressure greater than ambient pressure; a liquid pump providing a water-soluble liquid under pressure; an air inlet receiving air from the air pump; a liquid inlet receiving liquid from the liquid pump; and a nucleation device having a foam outlet, the nucleation device turbulently mixing the pressurized air and liquid to form foam; and a nozzle receiving the foam through a foam conduit, the internal passages of the nozzle and conduit adapted and configured to reduce turbulence in the foam, and the nozzle adapted and configured to deliver a slow stream of foam.

[0137] X4. Yet another aspect of the present invention relates to a method for supplying an air-foamed, water-soluble liquid cleaning agent to an inlet of a jet engine installed on an aircraft, the method including the steps of providing a source of water-soluble liquid cleaning agent, a liquid pump, an air pump, a turbulent mixing chamber, and a non-atomizing nozzle; mixing pressurized air and pressurized liquid in the mixing chamber to form a supply of foam; positioning the nozzle in front of the installed inlet; and flowing the supply of foam through the nozzle into the installed inlet.

[0138] X5. Another aspect of the present invention relates to an apparatus for foaming an aqueous liquid cleaning agent, comprising: means for mixing pressurized gas with a flowing aqueous liquid to form foam; means for growing the size of the foam cells; and means for reducing the size of the grown cells.

[0139] X6. Yet another aspect of the present invention relates to a method for planning foam cleaning of a jet engine, the method including the steps of quantifying a range of improvements to operating parameters of a group of jet engines achievable by foam cleaning of a group of jet engine components, operating the group of engines installed on an aircraft for a period of time, measuring the performance of the engines during operation, determining that the engines should be foam cleaned, and scheduling the foam cleaning of the engines.

[0140] X7. Yet another aspect of the invention relates to an apparatus for foam cleaning of a gas turbine engine, the apparatus comprising: a multi-wheel trailer having a cargo compartment with a waterproof liner; an exhaust outflow foam collector having a first sheet supported by a first pair of spaced apart ribs, the first ribs pivotally coupled to one end of the trailer, the ribs and the sheet cooperating to form an enclosed flow path, one end of the flow path having an inlet for receiving foam and the other end of the flow path having a drainage channel adapted and configured to provide foam outflow to the liner; and an inlet foam collector having a second sheet supported by a second pair of spaced apart ribs, the second ribs pivotally coupled to the other end of the trailer, the ribs and the sheet cooperating to provide a drainage path to the liner.

[0141] Still other specific examples relate to any of statements X1, X2, X3, X4, X5, X6, or X7 above, in combination with one or more of the following other aspects: It is also understood that any of the preceding X clauses includes a listing of individual features that can be combined with individual features of other X clauses.

[0142] Here, the first flow portion, the second flow portion, and the third flow portion have approximately the same flow area.

[0143] Here, the housing has an inner wall and an inner axis, and the direction of the inner flow passage is from the axis to the inner wall.

[0144] wherein at least two of the first, second, and third flow portions are coaxial, or the third flow portion is outermost from the first or second portion, or the first flow portion is innermost from the second or third portion.

[0145] The first, second, and third flow portions are coaxial, and the second flow portion is between the first and second portions.

[0146] The direction of the internal flow path is from the liquid inlet to the foam outlet.

[0147] The growth member comprises a wire mesh.

[0148] The wire mesh has a first mesh size, and the structuring member includes a wire mesh having a second mesh size that is smaller than the first mesh size.

[0149] The mesh comprises a plastic material or a metal material.

[0150] The structuring member includes an apertured plate, a lattice, or a fibrous matrix.

[0151] Forcing the first foam through the member increases the turbulence of the first foam.

[0152] The method further includes flowing the third foam into a chamber having an inlet and an outlet, the chamber adapted and configured to reduce turbulence of the third foam.

[0153] The chamber is adapted and configured to provide a more laminated flow of the third foam between the inlet and the outlet.

[0154] The mixing involves flowing the liquid in a first direction and injecting the gas in a second direction having a velocity component at least partially opposite to the first direction.

[0155] Flowing the second foam at a velocity further includes flowing a third foam onto the object at approximately the same velocity to clean the object.

[0156] The nozzle is adapted and configured to provide a stream of foam into a bleed duct of a jet engine.

[0157] The nozzle is adapted and configured to provide a stream of foam to a manifold of tubes attached to a jet engine.

[0158] The stream has a substantially constant diameter.

[0159] The nozzle has a first flow area and the conduit has a second flow area, the first flow area being approximately the same as the second flow area.

[0160] The foam outlet has a first flow area and the conduit has a second flow area, the first flow area being approximately the same as the second flow area.

[0161] The nozzle is one or more nozzles having a total flow area, and the foam outlet has an exit area, the exit area being approximately the same as the total flow area.

[0162] The nucleation device includes an air-pressurized plenum disposed within a chamber having a plurality of air flow openings and through which a flow of liquid is provided, the openings releasing air into the flowing liquid to form bubbles.

[0163] The air received by the nucleation device has a pressure greater than about 10 psig and less than about 120 psig, and the liquid received by the nucleation device has a pressure greater than about 10 psig and less than about 120 psig.

[0164] The incoming feed is at a velocity greater than about 3 feet per second and less than about 15 feet per second.

[0165] The flowing feed is a uniform stream of approximately constant diameter.

[0166] The provision includes a cell growth chamber downstream of the mixing chamber and further includes growing the size of the foam cells after mixing and before pouring.

[0167] The provision includes a turbulence reduction chamber downstream of the mixing chamber, further reducing turbulence of the mixed foam after mixing and before pouring.

[0168] The installed engine is approximately vertical in orientation and the pour is into the installed inlet without rotation of the engine.

[0169] The growing means includes a growing mesh and the reducing means includes a reducing mesh, the mesh size of the reducing mesh being smaller than the mesh size of the growing mesh.

[0170] The growing means is adapted and configured to provide a surface for attachment and fusion of foam cells from the mixing means.

[0171] The growing means includes a plurality of first passages, and the reducing means is adapted and configured to reduce the size of at least some of the grown cells by passing the grown cells through a plurality of second passages that are smaller than the first passages.

[0172] The mixing means is to inject gas into the flowing liquid from within the tube.

[0173] The mixing means is by providing pressurized gas into the liquid flowing through a porous metal filter.

[0174] The mixing means includes a motorized rotary impeller.

[0175] The mixing means imparts vortices to the flowing liquid by injecting gas.

[0176] The growing means is a vibrating rod or an ultrasonic wave transducer.

[0177] Further, it is up to the engine owner to determine, including providing the engine owner with the measured performance of their particular engine.

[0178] The operating parameter is the activation time.

[0179] The operating parameter is the engine's specific fuel consumption.

[0180] The operating parameters are the carbon or nitrogen oxides emitted by the engine.

[0181] The measuring occurs during commercial passenger aircraft operation.

[0182] Further, a vertical support is provided attached at one end to the trailer and at the other end to one of the first ribs, the vertical support maintaining the enclosed flow path in an upright position to facilitate gravity-induced drainage from the inlet to the drain.

[0183] Further included is a vertical support attached at one end to the trailer and at the other end to one of the second ribs, the vertical support maintaining the drainage path at an upward angle to facilitate gravity-induced flow toward the liner.

[0184] While the invention has been illustrated and described in detail in the drawings and foregoing description, it is to be considered exemplary and not restrictive in construction, it being understood that only certain embodiments have been shown and described, and that all changes and modifications which come within the scope of the invention are desired to be protected.

Claims

1. 1. An apparatus for foaming an aqueous liquid cleaning agent, the apparatus comprising: a housing defining an internal flow path having a first flow portion, a second flow portion, and a third flow portion, the housing having a gas inlet, a liquid inlet for the cleaning agent, and a foam outlet; the first flow section includes a gas plenum adapted and configured to receive gas under pressure from a gas inlet and include a plurality of openings, the gas plenum and the interior of the housing forming a mixing region that receives liquid from the liquid inlet and the gas released from the openings, the first flow section providing a first bubble of the liquid and the gas to the interior flow path; the second flow portion receives the first bubble and flows the first bubble through a bubble growth member adapted and configured to have a surface area for attachment and fusion of cells of the first bubble to form a second bubble; the third flow portion is adapted to receive the second foam and flow 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 form a third foam that is provided to the foam outlet, the foam structuring member comprising a wire mesh.

2. The apparatus of claim 1 , wherein the first flow portion, the second flow portion, and the third flow portion have substantially the same flow area.

3. 2. The device of claim 1, wherein the housing has an interior wall and an interior axis, and the interior flow path is oriented from the interior axis toward the interior wall.

4. The apparatus of claim 1 , wherein at least two of the first flow portion, the second flow portion, and the third flow portion are coaxial.

5. The apparatus of claim 4 , wherein the third flow portion is outboard of the first flow portion and the second flow portion.

6. The apparatus of claim 4 , wherein the first flow portion is inward from the second flow portion and the third flow portion.

7. 5. The apparatus of claim 4, wherein the first flow portion, the second flow portion, and the third flow portion are coaxial, and the second flow portion is between the first flow portion and the third flow portion.

8. The device of claim 1 , wherein the direction of the internal flow path is from the liquid inlet to the foam outlet.

9. The apparatus of claim 1 , wherein the bubble growth member comprises a wire mesh.

10. An apparatus as described in claim 9, wherein the wire mesh of the foam growth member has a first mesh size and the foam structuring member includes a wire mesh having a second mesh size smaller than the first mesh size.

11. The apparatus of claim 9, wherein the wire mesh of the bubble growth member comprises a plastic material.

12. The apparatus of claim 9, wherein the wire mesh of the bubble growth member comprises a metallic material.

13. The apparatus of claim 1 , wherein the foam structuring member comprises an aperture plate.

14. 1. A method for foaming an aqueous liquid cleaning agent, the method comprising: mixing the aqueous liquid cleaning agent with pressurized gas to form a first foam; flowing the first foam through a member to increase the cell size of the first foam to form a second foam; forming a third foam by flowing the second foam through a structure to reduce the size of the cells of the second foam, the structure comprising a wire mesh; A method comprising:

15. 15. The method of claim 14, further comprising increasing turbulence of the first bubble by flowing the first bubble through a member.

16. 15. The method of claim 14, comprising flowing the third foam into a chamber having an inlet and an outlet, the chamber adapted and configured to reduce turbulence of the third foam.

17. 17. The method of claim 16, wherein the chamber is adapted and configured to provide a laminar flow of the third bubble between the inlet and the outlet.

18. 15. The method of claim 14, wherein the mixing comprises flowing the liquid in a first direction and injecting the gas in a second direction having a velocity component at least partially opposite to the first direction.

19. 15. The method of claim 14, wherein the second foam is flowed at a velocity, the method including flowing the third foam onto an object at approximately the same velocity to clean the object.

20. 15. The method of claim 14, comprising operating a housing having an internal flow path having, in sequence, a first flow portion, a second flow portion, and a third flow portion, a gas inlet, a liquid inlet for the cleaning agent, and a foam outlet, the housing having an interior wall and an interior axis, the direction of the internal flow path being from the interior axis toward the interior wall, and the mixing occurring in the first flow portion.

21. 21. The method of claim 20, wherein the flowing of the first bubble occurs in the second flow portion and the flowing of the second bubble occurs in the third flow portion, and at least two of the first flow portion, the second flow portion, and the third flow portion are coaxial.

22. 22. The method of claim 21, wherein the third flow portion is outboard of the first flow portion and the second flow portion.

23. 22. The method of claim 21, wherein the first flow portion is inboard of the second flow portion and the third flow portion.

24. 22. The method of claim 21, wherein the first flow portion, the second flow portion, and the third flow portion are coaxial, and the second flow portion is between the first flow portion and the third flow portion.

25. 1. An apparatus for foaming an aqueous liquid cleaning agent, the apparatus comprising: mixing means for mixing pressurized gas with the flowing aqueous liquid to form a foam; growing means for growing the size of the formed bubbles; a reduction means for reducing the size of the grown cells, said reduction means comprising a wire mesh; An apparatus comprising:

26. the growing means is a mesh for growing, and the reducing means is a mesh for reducing; 26. The apparatus of claim 25, wherein the mesh size of the reducing mesh is smaller than the mesh size of the growing mesh.

27. 26. The apparatus of claim 25, wherein the growing mesh is adapted and configured to have a surface area for attachment and fusion of foam cells from the mixing means.

28. 26. The apparatus of claim 25, wherein the growing means includes a plurality of first passages, and the reducing means is adapted and configured to reduce the size of at least some of the grown cells by passing the grown cells through a plurality of second passages smaller than the first passages.

29. 26. Apparatus according to claim 25, wherein the mixing means is adapted to inject the gas into the liquid flowing from within the tube.

30. 26. The apparatus of claim 25, wherein the mixing means is adapted to provide the pressurized gas into the flowing liquid through a porous metal filter.

31. 26. The apparatus of claim 25, wherein the mixing means comprises a motorized rotary impeller.

32. 26. Apparatus according to claim 25, wherein the mixing means is adapted to impart a vortex to the flowing liquid by injection of a gas.

33. 26. The apparatus of claim 25, wherein the growing means is a vibrating rod.

34. 34. The apparatus of claim 33, wherein the growing means is an ultrasonic wave accelerator.

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