Patent Description:
The subject matter described herein relates to systems that clean machines.

Some machines having intricate internal mechanisms can be cleaned by directing a cleaning fluid into the machines. For example, foam detergent can be inserted into and pass through a turbine engine to remove contaminants from inside the engine. The foam carries contaminants out of the engine, leaving a cleaner engine that may have improved performance and/or increased remaining useful service life relative to prior to the engine cleaning.

Currently, known cleaning systems direct the cleaning fluid into the machines for a designated period of time to ensure that the machines are thoroughly cleaned. For example, foam washes of turbine engines may be performed for at least four hours, regardless of how dirty the machines are prior to the cleaning. This cleaning duration may last an unnecessarily long period of time, thereby keeping the turbine engine out of service for longer. Additionally, longer-than-needed cleanings can waste materials, such as the foam used to clean the turbine engine. <CIT> relates to an automated detection and control system and method for high pressure water wash application and collection applied to aero compressor washing. <CIT> relates to systems and devices for collecting and treating waste water from engine washing.

The present inventive subject matter will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:.

One or more embodiments of the inventive subject matter described herein provide systems and methods that measure characteristics of effluent from a foam detergent-cleaning of a turbine engine to determine how long the foam detergent-cleaning of the turbine engine is to be performed. This effluent can be a liquid phase effluent, or may be effluent in another phase. The characteristics are a turbidity (e.g., cloudiness) of the effluent, a conductivity of the effluent, a resistivity of the effluent, a salinity of the effluent. Different measured turbidities of the effluent, different measured conductivities of the effluent, different resistivities of the effluent, and/or different concentrations of the contaminant(s) in the effluent can be associated with different cleaning durations or remaining times until completion of the foam detergent-cleaning process. Depending on the measured characteristics, the system and method may shorten or prolong the cleaning process for the turbine engine. This can reduce the duration of many cleaning processes, which also reduces waste of the foam detergent.

For example, the foam detergent may be pumped into interior chambers of a turbine engine, pick up contaminants from surfaces inside the turbine engine, and exit from the turbine engine via one or more openings or ports as effluent. The effluent can carry contaminants from inside the turbine engine. The system can determine that effluents having larger turbidity values, larger measured conductivities, lower resistivities, greater measured salinities, more total dissolved solids, and/or greater concentrations of contaminants require longer cleaning times relative to effluents having smaller turbidity values, smaller measured conductivities, greater resistivities, smaller salinities, fewer total dissolved solids, and/or smaller concentrations of contaminants. Different values of turbidity values, conductivities, resistivities, salinities, total dissolved solids, and/or contaminant concentrations can be associated with different cleaning times. Shorter cleaning times can result in less foam detergent being used and the turbine engine being cleaned and available for use before longer cleaning times.

At least one embodiment of the inventive subject matter provides a system and method for optimizing the cleaning procedure for foam cleaning of a turbine engine.

The system and method can predict an exhaust gas temperature (EGT) margin recovery of a turbine engine based on the efficiency of the cleaning of the engine. For example, different changes in the measured characteristic of the effluent and/or different rates of change in the measured characteristic of the effluent can be associated with different changes (e.g., reductions) in the EGT margin of the engine.

During foam cleaning of a turbine engine, contaminants such as dust, dirt, oil, coke, and the like, are removed from individual stages and modules of the engine. Analysis of the effluent detergent as the effluent is discharged from the engine can be performed using sensing probes in an on-line and/or real-time mode (e.g., performed during the cleaning of the engine as additional foam detergent is directed into the engine). The concentrations of analytes such as calcium, sulphur or sulfate, and/or sodium in the effluent can be measured as indicative of the cleaning response of the turbine engine.

During the initial stages of cleaning, the amount of contaminants in the effluent may increase rapidly as the foam detergent selectively dissolves evaporite deposits (sulfates, carbonates, and/or halites), and liberate bound aluminosilicate clays which are accumulated in the turbine engine during service. Once the foam detergent has effectively dissolved these constituents, the analytes that comprise these accumulated evaporite deposits decrease rapidly. After a certain time period, for example <NUM> minutes, the rate of change of the calcium, sulphur, and/or sodium levels decreases, and the levels then start to reach asymptotes. At these asymptotic points, further cleaning time is considered to have diminishing returns with respect to improvement in the EGT margin and/or with respect to reduction in the fuel flow to the engine (which tends to reduce with cleaner engines).

The system and method can construct an analytic that establishes the asymptote behaviors for various characteristics of the effluent, such as the concentration of contaminants, the turbidity, the conductivity, the salinity, the total dissolved solids, and/or the resistivity of the effluent. These behaviors can be individualized for specific turbine engines (e.g., the asymptotes for different contaminants are different for different engine serial numbers), or can be specified for a class of turbine engines (e.g., the same asymptotes for the same make, same model, and/or same manufacturing date of turbine engines). The correlation between (a) the asymptotes and (b) the increase in EGT margin of the cleaned turbine engine and/or the decrease in fuel flow rate as a result of the foam cleaning also can be individualized for specific turbine engines or specified for a class of turbine engines. Optionally, the system and method (e.g., the controller described below) can use the analytic to create and/or modify maintenance schedules for individual turbine engines or classes of turbine engines, as described herein.

The asymptotes for the effluent characteristics can be established through the course of several foam wash campaigns. For example, the effluent characteristics can be measured for the same machine or a class of several turbine engines repeatedly at different times during each of several foam cleanings of the turbine engine or engines. The relationships between effluent characteristics and cleaning time can be determined from these repeated cleanings and measurements. The relationships can then be used to predict when the effluent characteristic reaches an asymptotic level or value, such as a level or value associated with a designated decrease in the exhaust gas temperature margin of the engine. Several designated decreases in the exhaust gas temperature margin can be measured after different cleanings of the same turbine engine or turbine engines. These measured exhaust gas temperature margins can be used to associate different asymptotic levels or values with different decreases in exhaust gas temperature margins.

At least one technical effect of the inventive subject matter described herein includes the minimizing or reducing of the time of the foam cleaning procedure and the volume of cleaning fluid used in the cleaning operation, as well as the maximizing or increasing of the exhaust gas temperature margin recovery of the cleaned turbine engine and/or reducing the flow rate of fuel into the engine (e.g., due to the cleaner engine operating more efficiently, thereby requiring less fuel to operate).

In one embodiment, the measured characteristics of the effluent of the foam detergent can be used to create and/or modify a maintenance schedule or cycle of the turbine engine. If the effluent of the detergent is measured to have large amounts of certain contaminants (e.g., sodium, sulfate, etc.), then these amounts of contaminants may indicate that the operations of the machine result in elevated contamination of the machine relative to the operations of other machines. For a turbine engine, higher amounts of sodium or sulfate in the detergent effluent can indicate that the turbine engine is traveling (e.g., propelling an aircraft) between locations having elevated amounts of these contaminants in the atmosphere. This can indicate that this turbine engine should be cleaned more often than other turbine engines that travel between other locations having lower amounts of the contaminants. The maintenance schedule of the turbine engine can accordingly be modified or created to provide for more frequent cleanings. Conversely, lower amounts of sodium or sulfate in the detergent effluent can indicate that the turbine engine is traveling between locations having lesser amounts of these contaminants in the atmosphere. This can indicate that this turbine engine does not need to be cleaned as often as other turbine engines that travel between other locations having greater amounts of the contaminants. The maintenance schedule of the turbine engine can accordingly be modified or created to provide for less frequent cleanings.

<FIG> illustrates a turbine engine foam cleaning system <NUM> according to the invention. The system <NUM> includes a controller <NUM> that monitors characteristics and/or changes in characteristics of effluent <NUM> that exits from a machine <NUM> being cleaned. The controller <NUM> represents hardware circuitry that includes and/or is connected with one or more processors. The one or more processors can include one or more microprocessors, field programmable gate arrays, integrated circuits, micro controllers, or the like. The controller <NUM> monitors characteristics of the effluent <NUM> and determines durations of cleaning processes for the turbine engine <NUM>, as described herein.

The machine <NUM> represents a turbine engine. The turbine engine <NUM> includes intricate internal components that accumulate contaminants, such as calcium, sulfur, sodium, and the like, due to operation of the turbine engine <NUM>. To remove those contaminants, the turbine engine <NUM> is cleaned by injecting a cleaning foam detergent <NUM> into interior regions or chambers of the turbine engine <NUM>. This foam detergent <NUM> is formed from one or more soap detergents in a foam form, such as a combination of a gas and liquid to form the foam detergent <NUM>.

The foam <NUM> or components used to create the foam <NUM> can be obtained from one or more container sources <NUM>. For example, one container source <NUM> may store liquid detergent that is pumped and mixed with air by a pumping device <NUM>. The pumping device <NUM> includes one or more conduits and/or pumps that pull or push the components used to create the foam detergent <NUM> from the container sources <NUM> into the turbine engine <NUM>.

The cleaning foam <NUM> is injected into the interior chambers of the turbine engine <NUM> through one or more openings, passages, ports, or the like, in the outer housing of turbine engine <NUM>. As the cleaning foam <NUM> passes through the turbine engine <NUM> as cleaning foam <NUM>, the foam <NUM> picks up, dissolves, or otherwise carries contaminants on surfaces inside the turbine engine <NUM> out of the turbine engine <NUM>. This foam <NUM> may exit from the turbine engine <NUM> via one or more openings, passageways, ports, or the like, as the effluent <NUM>. The effluent <NUM> may carry or otherwise contain a greater concentration of contaminants than the original cleaning foam <NUM>.

The system <NUM> includes one or more sensors <NUM> that measure characteristics of the effluent <NUM>. In one embodiment, the sensor <NUM> shown in
<FIG> represents an electrical characteristics sensor that measures an electrical characteristic of the effluent <NUM>. For example, the sensor <NUM> can include a liquid conductivity system that measures the conductivity of the effluent <NUM>. In one embodiment not part of the claimed invention, increased concentrations of contaminants in the effluent <NUM> can result in the sensor <NUM> measuring higher conductivity values of the effluent <NUM>. Conversely, reduced amounts of contaminants in the effluent <NUM> can result in the sensor <NUM> measuring smaller conductive values of the effluent <NUM>.

Optionally, the sensor <NUM> can measure resistivity of the effluent <NUM>. For example, the sensor <NUM> can represent a multimeter, voltmeter, or the like, that measures how resistive the effluent <NUM> is to conductance of electric current in the effluent <NUM>. Larger resistivity values of the effluent <NUM> can indicate smaller concentrations of contaminants in the effluent <NUM>. Conversely, smaller resistivity values indicate larger amounts of contaminants in the effluent <NUM>.

The sensor <NUM> can include a turbidity sensor or other optical-scattering sensor that measures how optically cloudy or clear the effluent <NUM> is. The sensor <NUM> can output a turbidity value, with the value indicative of how cloudy or clear the effluent <NUM> is. For example, larger turbidity values can indicate cloudier or more opaque effluent <NUM>, while smaller turbidity values can indicate clearer or more translucent foam <NUM>. Larger turbidity values can indicate that the effluent <NUM> includes greater amounts of contaminants than smaller turbidity values.

Optionally but not part of the claimed invention, the sensor <NUM> can include one or more sensors that measure the concentration of contaminants in the effluent <NUM>. The sensor <NUM> may represent a single sensor or multiple sensors that directly measure a number of contaminant particles, a mass of contaminant particles, a volume of contaminant particles, or the like, in the effluent <NUM>. For example, an ion selective electrode sensor can be used to measure the amount of one or more contaminants (e.g., sodium, calcium or the like) in the effluent <NUM>. The sensor <NUM> can include one or more sensors that measure the salinity of the effluent <NUM>.

The cleaning process may begin by the controller <NUM> directing the pumping device <NUM> to begin pumping the clean foam <NUM> into the turbine engine <NUM>. Optionally, the controller can direct operator to begin the pumping device <NUM> to direct the clean foam <NUM> into the turbine engine <NUM>, such as by audibly and/or visibly presenting instructions to the operator on an output device or via the output device <NUM>. The output device <NUM> represent one or more electronic devices that present information to the operator, such as electronic display, a speaker, a touchscreen, or the like.

During the cleaning process, the sensor <NUM> can measure the characteristic or characteristics of the effluent <NUM>. The sensor <NUM> can measure the characteristics repeatedly during the cleaning process, such that characteristics are measured as the effluent <NUM> exits from the turbine engine <NUM>. The measured characteristics can be communicated from the sensor <NUM> to the controller <NUM>. The controller <NUM> can save or otherwise record one or more the characteristics provided by the sensor <NUM> in a tangible and non-transitory computer readable medium, such as a computer memory <NUM>. The computer memory <NUM> can represent one or more computer hard drives, flash drives, optical discs, or the like.

The controller <NUM> can examine the characteristic(s) of the effluent <NUM> and determine a remaining cleaning time based on the characteristic(s). For example, the controller <NUM> can examine the characteristic that is measured and determine how much longer the cleaning process should continue (with the cleaning process involving clean foam detergent <NUM> being directed into the turbine engine <NUM>) before the characteristic measured by the sensor <NUM> reaches or comes within a designated range of an asymptotic limit or value. Responsive to the measured characteristic coming within this asymptotic limit, the controller <NUM> can automatically direct the pumping device <NUM> to stop directing additional foam detergent <NUM> into the turbine engine <NUM>, can automatically present instructions on output device <NUM> directing an operator to stop operation of the pumping device <NUM> from directing additional foam detergent <NUM> in the turbine engine <NUM>, or a combination thereof.

<FIG> illustrates one example of a characteristic <NUM> of the effluent <NUM> that is measured by the sensor <NUM> shown in <FIG>. The measured characteristic <NUM> is shown alongside a horizontal axis <NUM> that represents time and/or number of sample or sample number. The measured characteristic <NUM> also shown alongside a vertical axis <NUM> representative of a magnitude of the measured characteristic <NUM>. In the illustrated example, the measured characteristic <NUM> can represent the conductivity of the effluent <NUM> (not part of the claimed invention), the turbidity of the effluent <NUM>, the salinity of the effluent <NUM>, the total dissolved solids in the effluent <NUM> (not part of the claimed invention), or an amount of one or more contaminants in the effluent <NUM> (not part of the claimed invention).

As shown, the measured characteristic <NUM> may initially have a relatively low value that rapidly increases. The measured characteristic <NUM> may then gradually decrease, indicating that passage of the foam <NUM> through the turbine engine <NUM> is dissolving, carrying away, or otherwise removing contaminants from inside the turbine engine <NUM>. The measured characteristic <NUM> may continue to decrease over time and asymptotically approach a limit <NUM>. This limit <NUM> may be a goal or objective of the cleaning process, such as to reduce the amount of contaminants inside the turbine engine <NUM> to a level where the characteristic <NUM> is at or within a designated range <NUM> of the limit <NUM>. The limit <NUM> optionally can be referred to as an asymptotic limit. The limit <NUM> may be determined from previous measurements of the characteristics <NUM> of a previously used foam detergent <NUM> in previous cleanings of the same turbine engine <NUM>, of turbine engines <NUM> in the same class of turbine engines <NUM>, or a combination thereof. For example, the memory <NUM> can store an average, median, or the like of previously measured characteristics <NUM> during previous cleanings of the same or similar turbine engines <NUM> after the turbine engine <NUM> one turbine engines <NUM> are determined to be cleaned from contaminants. This average, median, or the like, may be used as the limit <NUM>.

The range <NUM> may be, for example, a range of <NUM>%, <NUM>%, <NUM>%, or the like, of the limit <NUM>. The characteristic <NUM> may be within the range to await of asymptotic limit <NUM> when the value of the characteristic <NUM> is within <NUM>% of the asymptotic limit <NUM>, within <NUM>% of the asymptotic limit <NUM>, or within <NUM>% of the asymptotic limit <NUM>. In some circumstances, the measured characteristic <NUM> may not reach levels that are at or below the asymptotic limit <NUM> even though the cleaning process extends over a long period of time, such as two or more hours. Alternatively, the measured characteristic <NUM> may eventually reach or fall below the asymptotic limit <NUM>, only after a very long cleaning time, such as two or three hours or more.

The controller <NUM> may use the measured characteristic <NUM> in a variety of ways to determine how long the cleaning process of the turbine engine <NUM> should last. For example, the controller <NUM> can track changes in the characteristic <NUM> and stop the cleaning process once the value of the characteristic <NUM> is at or within range <NUM> of the limit <NUM>. The sensor <NUM> can repeatedly measure the characteristic <NUM> and the controller <NUM> can repeatedly determine whether the cleaning process should continue based on how close or far the characteristic <NUM> is from a desired or designated value. In this example, the controller <NUM> may monitor the value of the measured characteristic <NUM> as the measured characteristic increases from an initial value toward the peak value shown in <FIG>. Following this peak value, controller <NUM> may examine the measured characteristic <NUM> at a first value <NUM>. At this first value <NUM>, the measured characteristic <NUM> has a relatively large value, indicating that there still are significant contaminants within the turbine engine <NUM> and the cleaning process should continue for a longer period of time.

The controller <NUM> may examine the value of the measured characteristic <NUM> one or more additional times as the cleaning process continues. This examination of the measured value of the characteristic <NUM> can be repeated by the controller <NUM> to determine whether the remaining duration of the cleaning process needs to be updated. For example, depending on the change or rate of change in the value of the measured characteristic <NUM>, the duration of the cleaning process may need to be extended or shortened depending on how effectively the foam <NUM> is removing contaminants from within the turbine engine <NUM>.

The controller <NUM> may repeatedly examine the characteristic of the effluent <NUM> at different times during the cleaning process to determine whether the duration of the cleaning process should be extended to ensure that enough contaminants are removed from the turbine engine <NUM> or whether the duration of the cleaning process should be stopped to prevent excess use of the foam detergent <NUM>. For example, the controller <NUM> can later examine the measured characteristic <NUM> and determine the characteristic <NUM> has a lower second value <NUM> and measure the characteristic <NUM> at an even later time and determine that the characteristic <NUM> has a lower third value <NUM>.

Responsive to the value of the measured characteristic <NUM> being at or within the designated range <NUM> of the limit <NUM>, the controller <NUM> may determine that the cleaning process is complete. For example, the values the measured characteristic <NUM> may be at or within the range <NUM> of limit <NUM>, thereby indicating that the marginal gain in additional cleaning of the turbine engine <NUM> is insubstantial relative to the cost of directing additional clean foam detergent <NUM> into the turbine engine <NUM>. As a result, controller <NUM> may automatically direct the pumping device <NUM> to stop directing clean foam detergent <NUM> into the turbine engine <NUM>, may direct the operator to stop the pumping device <NUM> from directing additional clean foam detergent <NUM> and the turbine engine <NUM>, or a combination thereof.

As another example of the controller <NUM> determining how long the cleaning process of the turbine engine <NUM> should last, the controller <NUM> may forecast how much longer the cleaning process is to last or be continued based on one or more prior measurements of the characteristic <NUM>. The controller <NUM> can determine an estimated remaining cleaning time based on the value of the measured characteristic <NUM> at one or more times. The measured values of the characteristic <NUM> can be compared with designated values that are associated with the turbine engine <NUM> or with a class of turbine engines <NUM>. For example, the value <NUM> of the characteristic <NUM> may indicate that the cleaning process should continue for an additional sixty minutes, the value <NUM> may indicate that the cleaning process should continue for an additional forty minutes, and the value <NUM> may indicate that the cleaning process should continue for an additional thirty minutes.

The designated cleaning times associated with different values of the characteristics <NUM> can be obtained from the memory <NUM>. The memory <NUM> can associate different remaining cleaning times with different values of the measured characteristic <NUM>. For example, larger values of effluent conductivity, larger values of contaminant concentration in the effluent, larger values of effluent turbidity, larger salinity values, more total dissolved solids, and/or smaller values of effluent resistivity can be associated with longer cleaning times than smaller values of effluent conductivity, smaller values of contaminant concentration in the effluent, smaller values of effluent turbidity, smaller salinity values, fewer total dissolved solids, and/or larger values of effluent resistivity. The designated cleaning times can be measured or calculated from previous cleanings of the same turbine engine <NUM> or a class of turbine engines <NUM>.

The controller <NUM> may repeatedly examine the characteristic of the effluent <NUM> at different times during the cleaning process to determine whether the duration of the cleaning process should be extended to ensure that enough contaminants are removed from the turbine engine <NUM> or whether the duration of the cleaning process should be shortened to prevent excess use of the foam detergent <NUM>. The change in the characteristic <NUM> of the effluent <NUM> may not change with respect to time as estimated. For example, the controller <NUM> may first determine that the measured value <NUM> of the characteristic <NUM> indicates that the cleaning should continue for an additional sixty minutes from the time at which the value <NUM> is measured. The controller <NUM> can later determine that the measured value <NUM> of the characteristic <NUM> indicates that the cleaning should continue for an additional forty minutes from the time at which the value <NUM> is measured. The controller <NUM> can later determine that the measured value <NUM> of the characteristic <NUM> indicates that the cleaning should continue for an additional thirty minutes from the time at which the value <NUM> is measured.

The controller <NUM> can update the remaining cleaning time based on the measured values of the characteristic <NUM>. The values of the characteristic <NUM> may not decrease or increase as expected. For example, the time between when the first and second values <NUM>, <NUM> of the measured characteristic <NUM> are measured may not coincide with the difference in remaining cleaning time durations associated with the different values <NUM>, <NUM>. The first value <NUM> may indicate to the controller <NUM> that the cleaning process needs continued for an additional sixty minutes. The second value <NUM> may be measured ten minutes after the first value <NUM>, but may indicate that only forty minutes cleaning time remains (before the characteristic <NUM> is at or within the range <NUM> of the limit <NUM>). This can occur because the foam <NUM>, <NUM> is removing contaminants from the turbine engine <NUM> more rapidly than expected.

Conversely, the values <NUM>, <NUM> of the measured characteristic may indicate that the cleaning process is proceeding slower than expected. For example, the second value <NUM> of the measured characteristic <NUM> may be obtained forty minutes after the first value <NUM>. This can indicate that, although the values <NUM>, <NUM> indicate that the cleaning process has continued for twenty minutes (due to the total cleaning process duration being reduced by twenty minutes from the first value <NUM> second value <NUM>), the contaminants may be removed from the turbine engine <NUM> by the foam <NUM> more slowly than expected.

The controller <NUM> can continue repeatedly examining the values of the characteristic <NUM> to change, update, or modify the remaining duration of the cleaning process. For example, the controller <NUM> may measure the characteristic <NUM> at the third value <NUM> at a time that is subsequent to when the values <NUM>, <NUM> are measured. In one example, the value <NUM> of the measured characteristic may indicate that the cleaning process needs to continue for an additional thirty minutes. The controller <NUM> can repeatedly examine the characteristic and optionally change the remaining cleaning time that the foam <NUM> is introduced into the turbine engine <NUM>.

<FIG> illustrates one example of a characteristic <NUM> of the effluent <NUM> that is measured by the sensor <NUM> shown in <FIG>. The measured characteristic <NUM> is shown alongside the horizontal axis <NUM> and the vertical axis <NUM> described above. In the illustrated example, the measured characteristic <NUM> can represent the resistivity of the effluent <NUM>.

The measured characteristic <NUM> may initially have a relatively large value that rapidly decreases. The measured characteristic <NUM> may then gradually increase, indicating that passage of the foam <NUM> through the turbine engine <NUM> is dissolving, carrying away, or otherwise removing contaminants from inside the turbine engine <NUM>. The measured characteristic <NUM> may continue to increase over time and asymptotically approach the limit <NUM>.

The controller <NUM> may use the measured characteristic <NUM> in a variety of ways to determine how long the cleaning process of the turbine engine <NUM> should last. For example, the controller <NUM> can track changes in the characteristic <NUM> and stop the cleaning process once the value of the characteristic <NUM> is at or within range <NUM> of the limit <NUM>. The sensor <NUM> can repeatedly measure the characteristic <NUM> and the controller <NUM> can repeatedly determine whether the cleaning process should continue based on how close or far the characteristic <NUM> is from a desired or designated value. In this example, the controller <NUM> may monitor the value of the measured characteristic <NUM> as the measured characteristic decreases from an initial value toward the smallest value shown in <FIG>. Following this smallest value, the controller <NUM> may examine the measured characteristic <NUM> at a first value <NUM>. At this first value <NUM>, the measured characteristic <NUM> has a relatively small value, indicating that there still are significant contaminants within the turbine engine <NUM> and the cleaning process should continue for a longer period of time.

The controller <NUM> may repeatedly examine the characteristic of the effluent <NUM> at different times during the cleaning process to determine whether the duration of the cleaning process should be extended to ensure that enough contaminants are removed from the turbine engine <NUM> or whether the duration of the cleaning process should be stopped to prevent excess use of the foam detergent <NUM>. For example, the controller <NUM> can later examine the measured characteristic <NUM> and determine the characteristic <NUM> has a greater second value <NUM>, and measure the characteristic <NUM> at an even later time and determine that the characteristic <NUM> has a greater third value <NUM>. The controller <NUM> can use these values of the characteristic <NUM> to determine when to stop the cleaning process and/or to predict when the cleaning process will be complete, as described above.

<FIG> illustrates another example of how a measured characteristic <NUM> of the effluent <NUM> can be used to determine or predict when to end a cleaning process. As described above, the values of the measured characteristic <NUM> may initially increase and then decrease over time with continued direction of the foam detergent <NUM> into the turbine engine <NUM>. The measured characteristic <NUM> may decrease over time at a rate that decreases while the measured characteristic <NUM> approaches an asymptotic limit. For example, the characteristic <NUM> can continue to decrease with continued cleaning of the turbine engine <NUM>, but the decreases in the characteristic <NUM> may become smaller over time with additional cleaning of the turbine engine <NUM>.

Optionally, the measured characteristic <NUM> can initially decrease and then increase over time with continued cleaning. In the illustrated example, there are several different limits <NUM>, <NUM>, <NUM>. These different limits <NUM>, <NUM>, <NUM> are associated with or representative of different levels of cleanliness of the inside surfaces of the turbine engine <NUM>. For example, the limit <NUM> is associated with the lowest value of the measured characteristic <NUM>, indicating the cleanest turbine engine <NUM> relative to the limits <NUM>, <NUM>. Conversely, the limit <NUM> is associated with the highest value of the measured characteristic <NUM>, indicating that the limit <NUM> is associated with a dirtier interior of the turbine engine <NUM>, relative to the thresholds or limits <NUM>, <NUM>.

The different thresholds or limits <NUM>, <NUM>, <NUM> may be associated with different changes in exhaust gas temperature margins of the turbine engine <NUM>. For example, because the limit <NUM> is associated with a reduced amount of contaminants in the turbine engine <NUM> relative to the limits <NUM>, <NUM>, the limit <NUM> may also be associated with a larger decrease in exhaust gas temperature margin of the turbine engine <NUM>. Similarly, the limit <NUM> may be associated with a decrease in the exhaust gas temperature margin that is not as large of a decrease associated with the limit <NUM>, but is a larger decrease than the decrease associated with the limit <NUM>.

The controller <NUM> and/or the operator of the system <NUM> may select the limit <NUM>, <NUM>, <NUM> based on a desired or selected reduction in the exhaust gas temperature margin of the turbine engine <NUM>. For example, the operator may select the limit <NUM> as the limit to which the characteristics <NUM> are to be reduced to determine when to end the cleaning process. The operator may select the limit <NUM> due to the decrease in exhaust gas margin not being enough to decrease for the limit <NUM>, but with the decrease the exhaust gas temperature margin associated with the limit <NUM> taking too long to reach.

As another example, the controller <NUM> may automatically select which limit <NUM>, <NUM>, <NUM> is used to determine when to terminate the cleaning process. For example, the controller <NUM> may measure the characteristic <NUM> at one or more points or times, and determine the approximate or estimate how long the cleaning process must continue for the value of the characteristic <NUM> to reach each of two or more of the limits <NUM>, <NUM>, <NUM>. The controller may examine these additional cleaning times associated with the different limits <NUM>, <NUM>, <NUM>, and may examine the exhaust gas temperature margin reductions associated with each of the limits <NUM>, <NUM>, <NUM>, and select one of the limits <NUM>, <NUM>, <NUM> to use in determining when to terminate the cleaning process.

The controller may examine the limit <NUM> and one or more values of the measured characteristic <NUM> and determined that it will require an additional cleaning time of one hundred fifty minutes for the characteristic <NUM> to reach the limit <NUM> or be within the designated range <NUM> of the limit <NUM>. The controller may examine the limit <NUM> and one or more values of the measured characteristic <NUM> and determine a required additional cleaning time of ninety minutes for the characteristic <NUM> to reach the limit <NUM> or be within the designated range <NUM> of the limit <NUM>. The controller <NUM> may examine the limit <NUM> and one or more values of the measured characteristic <NUM> and determine the required additional cleaning time of fifty-five minutes for the characteristic to reach the limit <NUM> or be within the designated range <NUM> of the limit <NUM>.

The controller <NUM> also can examine the reductions in exhaust gas temperature margins associated with each of the limits <NUM>, <NUM>, <NUM>. As one example, the exhaust gas temperature margin be expected to be reduced by <NUM>% when the characteristic <NUM> is reduced to or within the range <NUM> of the limit <NUM>, by <NUM>% with the characteristic <NUM> is reduced to or within the range <NUM> of the limit <NUM>, and by <NUM>% with the characteristic <NUM> reduced to or within the range <NUM> of the limit <NUM>. Based on these additional cleaning time durations and the corresponding reductions in exhaust gas temperature margins associated with the different limits <NUM>, <NUM>, <NUM>, the controller <NUM> may select which limit <NUM>, <NUM>, <NUM> the characteristic <NUM> is to be reduced to, and also base the remaining cleaning time duration on this selected limit <NUM>, <NUM> or <NUM>.

In continuing with the preceding example, the controller <NUM> may select the limit <NUM> because the limit <NUM> is associated with the exhaust gas temperature margin reduction that is greater than a desired reduction (for example, at least <NUM>% reduction) and is associated with an additional cleaning process time of ninety minutes, which is less than an upper limit on the cleaning time (for example one hundred twenty minutes). The controller <NUM> may then direct the pumping device <NUM> to continue pumping additional clean detergent foam <NUM> into the turbine engine <NUM> until this cleaning time duration is reached or until the characteristic <NUM> is at or within the range <NUM> of the limit <NUM>.

While the description herein focuses on the controller <NUM> examining a single characteristic of the effluent <NUM> to determine how much longer the cleaning process of the turbine engine <NUM> is to continue, in one embodiment, the controller <NUM> examines two or more different characteristics of the effluent <NUM>. For example, the controller <NUM> may obtain measured values of the conductivity and turbidity of the effluent <NUM>. The controller <NUM> can separately examine these characteristics to determine how much longer the cleaning process of the turbine engine <NUM> is to continue based on each of the characteristics <NUM> (e.g., based on how long it is predicted for each characteristic to reach an associated limit or be within the range of the limit). The controller <NUM> can then combine these cleaning times associated with the different characteristics. For example, the controller <NUM> can calculate an average or median of the remaining cleaning times associated with the different characteristics of the effluent <NUM>, and use the average or median as the remaining cleaning time used for the turbine engine <NUM>.

<FIG> illustrates a flowchart of one embodiment of a method <NUM> for foam cleaning of a turbine engine. The method <NUM> can represent the operations performed by the controller <NUM> in determining and controlling how long the pumping device <NUM> continues to direct clean foam detergent <NUM> into the turbine engine <NUM> to remove contaminants from interior surfaces and chambers of the turbine engine <NUM>.

At <NUM>, clean foam is directed into the turbine engine being cleaned. For example, controller <NUM> may direct the pumping device <NUM> to begin directing clean foam detergent <NUM> into the turbine engine <NUM>, as described above. The foam detergent <NUM> passes through the turbine engine as the foam <NUM>, and the foam <NUM> picks up, dissolves, or otherwise carries away contaminants from inside the turbine engine <NUM>. This foam <NUM> exits the turbine engine <NUM> as the effluent <NUM>, as described above.

At <NUM>, one or more characteristics of the effluent, such as turbidity or salinity, are measured. As described herein, the sensor <NUM> can measure the conductivity of the effluent <NUM>, resistivity of the effluent <NUM>, turbidity of the effluent <NUM>, and/or concentration of one or more contaminants in the effluent <NUM> as a characteristic.

At <NUM>, a remaining cleaning time is determined based on the measured characteristic of the effluent <NUM>. For example, the controller <NUM> can compare the value of the measured characteristic with the value of a designated limit, and predict how much longer the cleaning process is to continue until the value of the characteristic is expected to be at or within a designated range of the asymptotic limit. Different values of the measured characteristic can be associated with different remaining cleaning times until the characteristic reaches the limit or is within a designated range of the limit based on previous foam cleanings of the same turbine engine or a class of similar turbine engines. As another example, the controller <NUM> can continue monitoring the values of the characteristic and stop the foam cleaning once the characteristic is at or within the designated range of the designated limit.

At <NUM>, additional cleaning foam is directed into the turbine engine. For example, the pumping device <NUM> may continue directing clean foam detergent <NUM> into turbine engine <NUM>. At <NUM>, a determination is made as to whether a remaining cleaning time has been reached. For example, the controller <NUM> may determine whether the duration of the cleaning process, as determined at <NUM>, has been reached. If additional time remains for the cleaning process to be completed based on the measured value of the characteristic of the effluent that is determined at <NUM>, then flow of the method <NUM> can proceed toward <NUM>.

But, if the remaining cleaning time as determined at <NUM> has been reached, then flow of the method <NUM> can proceed from <NUM> toward <NUM>. At <NUM>, the cleaning process may be terminated. For example, responsive to determining that the remaining cleaning time determined at <NUM> has been reached, the controller <NUM> may automatically direct the pumping device <NUM> to stop directing additional foam <NUM> into the turbine engine <NUM>. Operation of the method <NUM> may then terminate.

Returning to the description of the decision made at <NUM>, if the cleaning time determined at <NUM> has not yet been reached, then flow of the method <NUM> can proceed from <NUM> toward <NUM>. At <NUM>, the characteristic or characteristics of the effluent <NUM> are measured again. The sensor <NUM> can measure the characteristic or characteristics of the effluent <NUM>, and communicate these characteristic or characteristics to the controller <NUM>.

At <NUM>, a determination is made as to whether or not the remaining cleaning time needs to be changed based on the measured characteristic. For example, controller <NUM> may examine the change, rate of change, or other approach of the characteristic of the effluent <NUM> toward the desired or selected limit. The recently measured characteristic of the effluent <NUM> may indicate that more or less cleaning time may be needed to reach the designated limit. The controller <NUM> may determine if additional cleaning time is needed, or if less cleaning time is needed, and may change the remaining cleaning time based on the approach of the characteristic of the effluent <NUM> to the limit. As a result, flow of the method <NUM> can proceed from <NUM> to <NUM>. Alternatively, if the recently measured characteristic of the effluent <NUM> does not indicate any time needs to be updated, then flow of the method <NUM> can proceed from <NUM> toward <NUM>.

At <NUM>, the remaining cleaning time of the turbine engine is updated. If the characteristic measured at <NUM> indicates that the characteristic is not reducing or increasing at a rate commensurate with the expected change in characteristic during the foam cleaning of the turbine engine <NUM>, the controller <NUM> may determine that the remaining cleaning time needs to be extended or decreased. For example, if the characteristic measured at <NUM> indicates that the cleaning process needs to continue for an additional ninety minutes but, thirty minutes later, the characteristic measured at <NUM> indicates that the cleaning processes should continue for an additional eighty minutes, then the controller <NUM> may extend the cleaning time.

As another example, if the characteristic measured at <NUM> indicates of the cleaning processes continue for an additional ninety minutes but, thirty minutes later, the characteristic measured at <NUM> indicates of the cleaning process needs to continue for an additional forty minutes, the controller may reduce the cleaning time. In this way, this portion of the method <NUM> can proceed in a loop-wise manner to repeatedly measure characteristics of the effluent <NUM> to determine and/or update how much longer the cleaning process needs to continue before the characteristic of the effluent <NUM> is expected to be at or within a designated range of the selected limit.

In one embodiment, the effluent <NUM> that exits from the turbine engine <NUM> can be recycled or otherwise re-used as some or all of the foam detergent <NUM> that is directed into the same turbine engine <NUM> or another turbine engine <NUM> at a later time. For example, the effluent <NUM> can be examined (as described herein) and, depending on the value or values of the characteristic <NUM>, <NUM> of the effluent <NUM>, at least some of the effluent <NUM> can be added to the source <NUM> of foam detergent <NUM>. If the characteristic <NUM> of the effluent <NUM> exceeds a designated threshold that is associated with healthy detergent foam <NUM> (e.g., the threshold <NUM>, <NUM>, and/or <NUM>), then the characteristic <NUM> may indicate that the effluent <NUM> is too dirty or cannot otherwise be used as part of the detergent <NUM> that is introduced into the turbine engine <NUM>. For example, a large value for the characteristic <NUM> can indicate that the effluent <NUM> is too dirty to be recycled as detergent foam <NUM> that is directed into the turbine engine <NUM> to clean the turbine engine <NUM>. As long as the characteristic <NUM> of the effluent <NUM> remains at or below the designated threshold, however, then the effluent <NUM> may continue to be at least partially recycled as the detergent foam <NUM> that is directed into the turbine engine <NUM> to clean the turbine engine <NUM>.

One or more conduits may receive and direct the effluent <NUM> into one or more filters that clean or otherwise remove contaminants from the effluent <NUM>. The characteristic of the effluent <NUM> can be measured before and/or after the effluent <NUM> is cleaned by the filters. A pump (e.g., the pumping device <NUM> or another pumping device) can direct at least some of the effluent <NUM> back to the source <NUM> after the portion of the effluent <NUM> passes through and is cleaned by the filter(s). The controller <NUM> can monitor the characteristic of the effluent <NUM> measured before and/or after the effluent <NUM> passes through the filter(s) and, depending on the value of the characteristic, the controller <NUM> can stop the pumping device from directing the effluent <NUM> back into the source <NUM>.

In one embodiment, the controller <NUM> can examine the measured characteristics of the effluent <NUM> of the foam detergent <NUM> and be used to determine whether to create and/or modify a maintenance schedule or cycle of the turbine engine <NUM>. If the effluent of the detergent is measured to have large amounts of certain contaminants (e.g., sodium, sulfate, etc.), then these amounts of contaminants may indicate that the operations of the turbine engine <NUM> result in elevated contamination of the turbine engine <NUM> relative to the operations of other turbine engines. For a turbine engine as the turbine engine <NUM>, higher amounts of sodium or sulfate in the effluent <NUM> can indicate that the turbine engine is operating in locations having elevated amounts of these contaminants in the atmosphere. This can indicate that this turbine engine should be cleaned more often than other turbine engines that operate in locations having lower amounts of the contaminants. The controller <NUM> can then create or modify the maintenance schedule of the turbine engine to provide for more frequent cleanings. Conversely, lower amounts of sodium or sulfate in the effluent <NUM> can indicate that the turbine engine is operating in locations having lesser amounts of these contaminants in the atmosphere. This can indicate that this turbine engine does not need to be cleaned as often as other turbine engines that operate in locations having greater amounts of the contaminants. The controller <NUM> can then create or modify the maintenance schedule of the turbine engine to provide for less frequent cleanings.

Furthermore, references to "one embodiment" of the presently described subject matter are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments "comprising" or "having" an element or a plurality of elements having a particular property may include additional such elements not having that property.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. While the dimensions and types of materials described herein are intended to define the parameters of the disclosed subject matter, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the subject matter described herein should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein. " Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

Claim 1:
A system comprising:
a pumping device (<NUM>) configured to clean an internal structure of a turbine engine (<NUM>) by directing a foam detergent (<NUM>) into the turbine engine (<NUM>) to reduce an amount of one or more contaminants inside the turbine machine (<NUM>), the foam detergent (<NUM>) directed into the turbine engine (<NUM>) such that an effluent (<NUM>) portion of the foam detergent (<NUM>) exits from the turbine engine (<NUM>) with at least some of the contaminants;
one or more sensors (<NUM>) configured to measure a turbidity of the effluent (<NUM>) portion of the foam detergent (<NUM>) that exits from inside the turbine engine (<NUM>) and/or a salinity of the effluent (<NUM>) portion of the foam detergent (<NUM>), that exits from inside the turbine engine (<NUM>); and
a controller (<NUM>) configured to determine a cleaning time period during which the foam detergent (<NUM>) is to be directed into the turbine engine (<NUM>) by the pumping device (<NUM>) based on the turbidity and/or the salinity that is measured from the effluent (<NUM>) portion of the foam detergent (<NUM>), the controller (<NUM>) configured to direct the pumping device (<NUM>) to continue directing the foam detergent (<NUM>) into the turbine engine (<NUM>) during the cleaning time period, the controller (<NUM>) also configured to direct the pumping device (<NUM>) to stop flow of the foam detergent (<NUM>) into the turbine engine (<NUM>) responsive to expiration of the cleaning time period.