Patent Publication Number: US-2023152298-A1

Title: Analysis device for detecting solid particles in a lubricant

Description:
TECHNICAL FIELD 
     The present disclosure concerns the field of lubricant monitoring in machines, and more specifically an analysis device for detecting solid particles in suspension in a lubricant. 
     PRIOR ART 
     To reduce operating costs, it is ascertained throughout the entire mechanical sector that lubricant maintenance and change times are being extended. In the more specific field of combustion engines and in particular gas turbine engines such as those used in aeronautics, a gradual reduction is observed in lubricant consumption leading to longer use of a lubricant before it is changed. 
     With this reduction in the frequency of lubricant change, there is also a reduction in the opportunities to observe and/or analyze the quality of a lubricant at each oil change. Yet this observation and analysis of used oil allows the detection not only of unexpected changes in the properties of the lubricant itself, but also, through these properties of the used oil, such as the presence of fuel or filings in the lubricant, of malfunctions in the lubricated machine. 
     It is already known, see for example French patent application having publication number FR 2 927 401 A1, to integrate indwelling sensors and in particular sensors of metal particles in the lubrication circuit. American patents U.S. Pat. Nos. 4,657,671 A, 5,604,441 A and 3,432,750 disclose devices combining sensors of ferromagnetic and non-ferromagnetic particles for separate detection thereof. 
     However, despite the presence of such sensors, the simultaneous detection of different types of solid particles in suspension can still remain desirable through better distinguishing therebetween. 
     DESCRIPTION OF THE INVENTION 
     A first aspect of the invention concerns an analysis device for detecting solid particles in suspension in a lubricant. The analysis device may comprise one or more ferromagnetic solid particle sensors, and one or more other sensors able to detect non-ferromagnetic solid particles. By “non-ferromagnetic solid particle” in this context any solid particle can be understood which has a magnetic susceptibility equal to or less than 10 4  for example. These other sensors can be offset in a direction perpendicular to a main direction of flow of the lubricant with respect to the ferromagnetic solid particle sensors, and the analysis device may further comprise one or more magnets arranged so as to attract the ferromagnetic solid particles towards the ferromagnetic solid particle sensors by drawing them away from the other sensors. The ferromagnetic solid particle sensors can in particular be inductive sensors, wherein each may comprise a winding oriented in a direction perpendicular to the main direction of flow of the lubricant, and the sensors of non-ferromagnetic solid particles can be optical and/or acoustic sensors and in particular be configured to detect the wavelength and/or light intensity reflected by non-ferromagnetic solid particles. Each of the ferromagnetic solid particle sensors can in particular be directional and oriented to detect ferromagnetic solid particles in a direction perpendicular to the main direction of flow of the lubricant, and each of said other sensors can in particular be directional and oriented to detect non-ferromagnetic solid particles in a direction parallel to the main direction of flow of the lubricant. 
     By means of this arrangement, the ferromagnetic and non-ferromagnetic solid particles in suspension in the lubricant can be detected separately. This characterization of the solid particles in suspension in the lubricant therefore allows better diagnosis of their origin and more accurate prediction of the consequences of this contamination of the lubricant. 
     In a second aspect, the analysis device may further comprise one or more grids arranged crosswise to the main direction of flow of the lubricant, to separate per size the solid particles in suspension in the lubricant. Each of said other sensors can therefore be arranged to detect non-ferromagnetic solid particles on each of the grids. For this purpose, each of said other sensors can particularly be arranged facing a corresponding grid from among said grids. The grids may particularly comprise at least one first grid and a second grid arranged downstream of the first grid in the main direction of flow of the lubricant, the second grid being finer than the first grid so as to separate solid particles of smaller size. It is therefore possible, in addition to separation between solid ferromagnetic and non-ferromagnetic particles, to obtain separation per size allowing even better characterization of all the solid particles in suspension in the lubricant. 
     A third aspect of this disclosure concerns a lubricant monitoring system comprising the analysis device of the first aspect, one or more inlet connections and one or more outlet connections. Each of the inlet connections is able to be to connected, in particular releasably, to a lubricant circuit to allow the entry of lubricant from the lubricant circuit into the analysis devices, and each of the outlet connections is connectable, in particular releasably, to the lubricant circuit so as to allow return of the lubricant through the analysis devices towards the lubricant circuit. 
     By means of these characteristics, it is possible to install this lubricant monitoring system on a lubricant circuit for continuous or intermittent monitoring of one of more parameters of the lubricant over an operating period of the lubricant circuit. In particular, this installation can be temporary. 
     If the lubricant monitoring system comprises several of said inlet connections, it may further comprise a selective inlet valve to place said inlet connections selectively in fluid communication with the analysis devices. It is thus possible alternately to select several lubricant sample points to be monitored, thereby allowing the identification of specific sources of lubricant degradation within the circuit. 
     Additionally, when the lubricant monitoring system further comprises several of said outlet connections, it may also comprise a selective outlet valve to place said outlet connections selectively in fluid communication with the analysis devices. The selective inlet valve and selective outlet valve can be coupled together to synchronize their selections and therefore return the lubricant back towards the same branch of the lubrication circuit on which it was sampled. The selective inlet valve and/or selective outlet valve may comprise a rotative valve body e.g. in cylinder form to allow selection of an inlet connection and/or outlet connection by rotating this valve body. However, alternative shapes of selective valves e.g. slide-type can also be considered. 
     To ensure operation of the sensors, and even of other parts of the lubricant monitoring system, they may further comprise an electric powering device. This electric powering device may particularly comprise a turbine able to be actuated by lubricant flow through the lubricant monitoring system and/or a thermocouple thermally interposed between the lubricant and a heat sink, to ensure independent electric powering of the lubricant monitoring system by drawing on the thermal or mechanical energy of the lubricant itself. However, it could also be envisaged that the electric powering device comprises a power storage device alternatively to or in combination with said turbine and/or thermocouple. 
     The lubricant monitoring system may also comprise a communication device connected to the analysis device to transmit data captured by the sensors to a user and/or external device. 
     Additionally, the lubricant monitoring system may further comprise a second analysis device including one or more lubricant quality sensors such an optical sensor, sensor of electrical conductivity, temperature sensor and/or viscosity sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be clearly understood and the advantages thereof will become better apparent on reading the following detailed description of embodiments illustrated as nonlimiting examples. The description refers to the appended drawings in which: 
         FIG.  1    is a partial schematic illustration of a lubricant circuit with a lubricant monitoring system according to one embodiment. 
         FIG.  2    is an illustration in perspective of a selective inlet valve and outlet valve having coupled rotative bodies, of the monitoring system in  FIG.  1   . 
         FIG.  3 A  is a cross-sectional view along plane III-III of the selective valve in  FIG.  2    at a first position. 
         FIG.  3 B  is a cross-sectional view along plane III-III of the selective valve in  FIG.  2    at a second position. 
         FIG.  3 C  is a cross-sectional view along plane III-III of the selective valve in  FIG.  2    at a third position. 
         FIG.  3 D  is a cross-sectional view along plane III-III of the selective valve in  FIG.  2    at a fourth position. 
         FIG.  4    is a schematic illustration of an analysis device belonging to the monitoring system in  FIG.  1   . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG.  1    schematically illustrates part of a lubricant circuit  1  able to be used to lubricate a machine, and in particular a turbomachine such as a turbojet aeroengine. However, other applications in particular aeronautic, automotive, marine or railway applications can also be envisaged. As illustrated in  FIG.  1   , this lubricant circuit  1  may comprise a plurality of branches  10 ,  20 ,  30  which may derive from different members or zones of the lubricated machine and meet up as illustrated in a common line  40  downstream of corresponding pumps  11 ,  21 ,  31 . Each of the branches  10 ,  20 ,  30 , as illustrated, may comprise an upstream branch  12 ,  22 ,  32  and downstream branch  13 ,  23 ,  33  allowing connection thereof to the lubricant monitoring system  100  parallel to branches  10 ,  20 ,  30 . The upstream branches  12 ,  22 ,  32  and downstream branches  13 ,  23 ,  33  can all be arranged upstream of the corresponding pumps  11 ,  21 ,  31 . For example, they can substitute for orifices conventionally used to insert magnetic sensors of metal particles in the lubricant circuit  1 . Plugs, not illustrated, are able to shut off these upstream  12 ,  22 ,  32  and downstream  13 ,  23  , 33  branches when the lubricant monitoring system  100  is not connected to the lubricant circuit  1 . 
     The lubricant monitoring system  100  may comprise an inlet connection  101 ,  102 ,  103  and outlet connection  111 ,  112 ,  113  for each of the branches  10 ,  20 ,  30  of the lubricant circuit  1 . Each of the inlet connections  101 ,  102 ,  103  can be releasably connected to one from among the plurality of upstream branches  12 ,  22 ,  32 . Similarly, each of the outlet connections  111 ,  112 ,  113  can be releasably connected to one from among the plurality of downstream branches  13 ,  23 ,  33 . 
     Although, in the illustrated example, the lubricant circuit  1  comprises three branches  10 ,  20 ,  30  and the lubricant monitoring system  100  therefore has the same number of inlet connections  101 ,  102 ,  103  and outlet connections  111 ,  112 ,  113 , it can be envisaged to have a different number of branches and hence of corresponding inlet and outlet connections. It can also be envisaged to have a greater number of inlet connections than outlet connections if, for example, at least some of the branches meet up at a confluence upstream of the pumps, so that an outlet connection of the lubricant monitoring system is connectable to the lubricant circuit between the confluence and downstream pump, or if a single outlet connection is connected to the common line  40  downstream of the pumps  11 ,  21 ,  31 , which would additionally require the integration of a pump in the lubricant monitoring system  100 . 
     Between the inlet connections  101 ,  102 ,  103  and outlet connections  111 ,  112 ,  113 , the lubricant monitoring system  100  may comprise a selective inlet valve  120 , a first analysis device  130 , a second analysis device  140 , a power extraction device  150 , and a selective outlet valve  160  in fluid communication in series. Additionally, the lubricant monitoring system  100  may comprise a control unit  170 , a communication device  180  and an electric powering device  190  which may comprise the power extraction device  150 . 
     The selective inlet valve  120  can be configured to selectively place each of the inlet connections  101 ,  102 ,  103  in fluid communication with a line  200  passing through the analysis devices  130 ,  140  and even the power extraction device  150  downstream. The selective inlet valve  120  can also be configured to isolate line  200  from the assembly of inlet connections  101 ,  102 ,  103  so that the lubricant may continue to circulate on each of the branches  10 ,  20 ,  30  of the lubricant circuit  1  without being taken for sampling. Similarly, the selective outlet valve  160  can be configured to selectively place line  200  downstream of the analysis devices, even downstream of the power extraction device  150 , in fluid communication with each of the outlet connections  111 ,  112 ,  113 , or to isolate the same from the assembly of outlet connections  111 ,  112 ,  113 . The selective inlet  120  and outlet  160  valves may particularly be in the form of valves with rotative bodies, preferably coupled together for example mechanically as illustrated in  FIG.  2   . 
     As can be seen in  FIGS.  2  and  3 A to  3 C , the rotative valve bodies  121 ,  161  of the selective inlet valve  120  and selective outlet valve  160  respectively, may each have a radial through-hole  122 ,  162  and an axial through-hole  123 ,  163  in fluid communication with each other. The radial through-hole  122 ,  162  can open onto a peripheral surface of the rotative valve body  121 ,  161 , while the axial through-hole  123 ,  163  can open onto a front surface of the rotative valve body  121 ,  161 . The selective inlet valve  120  and selective outlet valve  160  may further each comprise a valve casing  124 ,  164  with a central orifice  125 ,  165  which may lie opposite the axial through-hole  123 ,  163 , and peripheral orifices  126 ,  127 ,  128 ,  166 ,  167 ,  168 . 
     The radial orifices  126 ,  127 ,  128  of the valve casing  124  of the selective inlet valve  120  can each be in fluid communication with one of the inlet connections  101 ,  102 ,  103 . The central orifice  125  of the valve casing  124  can be in fluid communication with line  200 . The radial through-hole  122  of the rotative valve body  121  of the selective inlet valve  120  can be selectively placed facing each of these peripheral orifices  126 ,  127 ,  128  via relative rotation of the rotative valve body  121  in relation to the valve casing  124  about its central axis X, so as selectively to place in fluid communication each of the inlet connections  101 ,  102 ,  103  with line  200  as illustrated in  FIGS.  3 A to  3 C . The radial through-hole  122  of the rotative valve body  121  of the selective inlet valve  120  is also able to turn towards an intermediate position as illustrated in  FIG.  3 D  to isolate the line  200  from the three inlet connections  101 ,  102 ,  103 . 
     Analogously, the radial orifices  166 ,  167 ,  168  of the valve casing  164  of the selective outlet valve  160  can each be placed in fluid communication with one of the outlet connections  111 ,  112 ,  113 . The central orifice  165  of the valve casing  164  can be in fluid communication with the line  200 . The radial through-hole  162  of the rotative valve body  161  of the selective outlet valve  160  can be selectively placed facing each of these peripheral orifices  166 ,  167 ,  168  via relative rotation of the rotative valve body  161  in relation to the valve casing  164  about its central axis X, to selectively place in fluid communication each of the outlet connections  111 ,  112 ,  113  with the line  200 , or to isolate this line  200  from the three outlet connections  111 ,  112 ,  113 . 
     As illustrated in  FIG.  2   , the rotative valve bodies  121 ,  161  can be mechanically coupled via a common rotating shaft  210  which in turn can be mechanically coupled to an actuation device  220  such as a stepper motor electrically connected to the control unit  170  for electrical powering and control thereof. Therefore, the respective selections of the selective inlet valve  120  and selective outlet valve  160  can be synchronized. However, the selective inlet valve  120  and selective outlet valve  160  can be configured differently to the illustrated rotating configuration, and can be in the form of slide valves for example. 
     As illustrated in  FIG.  4   , the first analysis device  130  can be a device analyzing solid particles in suspension in the lubricant. It may comprise a casing  131  with a succession of mesh grids  231  that are increasingly finer between the inlet  132  and outlet  133  thereof, to separate the solid particles per size. For example, a first grid  231  can have a mesh size of 8 mm 2 , a second grid  231  downstream of the first grid  231  can have a mesh size of 4 mm 2 , a third grid  231  downstream of the second grid  231  can have a mesh size of 1 mm 2 , a fourth grid  231  downstream of the third grid  231  can have a mesh size of 0.1 mm 2  and a fifth grid  231  downstream of the fourth grid  231  can have a mesh size of 0.02 mm 2  so that each retains particles of greater cross-section than the corresponding mesh size. The mesh size of the successive grids could alternatively follow inverse square progression following formula Ai=A 1 /i 2 , where i is the position of the grid from upstream to downstream and A i  is the mesh size of the respective grid. Alternative means for separating solid particles per size e.g. centrifugation can also be envisaged. 
     The first analysis device  130  may also comprise ferromagnetic particle sensors  234 , lying flush for example on the walls of the casing  131 , upstream of each grid  231 , to detect ferromagnetic particles of different corresponding sizes. These ferromagnetic particle sensors  234  can be inductive sensors for example and notably each comprise a winding (not illustrated) having an axis that can be oriented perpendicular to the main direction of flow of the lubricant between the inlet  132  and outlet  133  of the first analysis device  130 , to detect ferromagnetic particles in the axis of the winding via variation of a magnetic field passing through the winding. Therefore, each sensor  234  can be configured, with at least 65% efficacy for example, to detect a ferromagnetic particle of at least 0.130 mg for example with a length-width size ratio of up to 20:1 for example. 
     One or more magnets  250  can be arranged on the periphery of the casing  131  to attract ferromagnetic particles towards the ferromagnetic particle sensors  234 . Each of these magnets  250  can particularly be arranged coaxial to the winding of one of the ferromagnetic particle sensors  234 , so as not only to attract the ferromagnetic particles towards the corresponding sensor  234  but also to provide the magnetic field of which the variation will allow detection thereof by the sensor  234 . Each magnet  250  can be a permanent magnet or alternatively an electromagnet with a winding which can then lie coaxial to that of the corresponding sensor  234 . Optionally, another magnet  250 ′ oriented along the same polarity can be arranged facing each of the magnets  250  on an opposite wall of the casing  230 . Magnets  250  can have different intensities and in particular intensities increasing in the direction of flow of the lubricant from the inlet  132  to the outlet  133  of the first analysis device  130 , to compensate for the decreasing size of the ferromagnetic solid particles passing through the successive grids  231 . To obtain these different intensities, they can be electromagnets for example having windings with a different number of turns powered by the same voltage. It can also be envisaged to control the powering voltage of each electromagnet, jointly or separately, and in particular as a function of the lubricant flow passing through the first analysis device  130 . The powering voltage of each electromagnet can be between 0 and 24 V for example, preferably between 120 mV and 4 V. 
     The first analysis device  130  may also comprise other particle sensors  238  which can be arranged for example in a central zone of the casing  131  facing each grid  231 , to detect non-ferromagnetic particles of different corresponding sizes retained on each grid  231 . These other particle sensors  238  can particularly be acoustic and/or optical sensors. In particular, they can be optical sensors to perform reflectometry, configured to detect a wavelength and/or light intensity reflected by the non-ferromagnetic solid particles, and thereby allow a distinction to be made between different types of non-ferromagnetic solid particles. The light reflected by the non-ferromagnetic solid particles can derive from one or more sources, for example light-emitting diodes integrated in each sensor  238  or external thereto. To allow illumination of non-ferromagnetic solid particles through the lubricant, the light emitted by these sources and captured by the sensors  238  can be restricted to some spectral bands and in particular the visible spectrum. Strain sensors (not illustrated) can also be coupled with each grid  231  and contribute towards measuring the quantity of solid particles on each of the grids  231 . 
     By offsetting the ferromagnetic particle sensors  234  perpendicularly to the main direction of flow of the lubricant, these possibly being arranged on the periphery of the casing  131  in relation to the other sensors  238  positioned in the central zone of the casing  131 , and by means of the arrangement of the magnets  250  to attract ferromagnetic particles towards the sensors  234  by drawing them away from the other sensors  238 , it is possible to prevent the detection of ferromagnetic solid particles by these other sensors  238  and thereby separately detect the two types of solid particles. Each of the sensors  234  and  238  can be connected to the control unit  170  to transmit thereto the detection of these particles. 
     The second analysis device  140  may comprise one or more other sensors such as an electrical conductivity sensor, optical sensor to capture the colour and/or turbidity of the lubricant, a viscosity sensor, a thermometer, a manometer, a vibration sensor and/or an acoustic sensor. Each of these sensors of the second analysis device  140  may also be connected to the control unit  170  to transmit thereto the data they have captured. 
     The power extraction device  150  can be a turbine able to be pulsed by the lubricant flow through line  200 , and coupled to an electric generator or a thermocouple able to produce electricity from the thermal gradient between the lubricant circulating through line  200  and a heat sink e.g. a radiator, an airstream and/or a fuel circuit. This power extraction device  150  can be electrically connected to a power storage device  155  which can be a battery for example, a capacitor and/or flywheel to form the electric powering device  190 . This electric powering device  190  can be electrically connected to other members of the lubricant monitoring system  100  so as to ensure powering thereof, optionally even independently, 
     However, alternatively, or in addition to this electric powering device  190 , an external electrical connection can also be envisaged. Additionally, it can also be envisaged that the electric powering device  190  does not comprise a power extraction device, and ensures the electrical powering of the lubricant monitoring system  100  solely from the power previously stored in the power storage device  155 , or alternatively it does not comprise a power storage device and ensures the electrical powering of the lubricant monitoring system from the power drawn by the power extraction device  150  from the flow of lubricant passing through it. 
     The control unit  170  can be an electronic computer, optionally programmable. It can therefore be integrated into an integrated circuit or microprocessor and incorporate a data storage member. Finally, the control unit  170  is connected to a communication device  180  to transmit the data captured by the different sensors of the analysis devices  130 ,  140 , and/or the results of their analysis by the control unit, to external systems and/or to users. This communication device  180 , as illustrated, can be a wireless communication device, but also a simple electrical and/or optical connector for data transmission. The control unit  170  can also be configured to place the lubricant monitoring system  100  in inactive mode, in particular by actuating the selective inlet  120  and outlet  160  valves to isolate line  200  from the inlet  101 ,  102 ,  103  and outlet  111 ,  112 ,  113  connections, for example in the event that the electric powering device  190  is no longer able to provide sufficient electrical power for normal operation of the lubricant monitoring system  100 . 
     To use the lubricant monitoring system  100 , it can first be installed by connecting an inlet connection  101 ,  102 ,  103  and an outlet connection  111 ,  112 ,  113  of the lubricant monitoring system  100  to each of the branches  10 ,  20 ,  30  of the lubricant circuit  1  through the respective upstream branch  12 ,  22 ,  32  and downstream branch  13 ,  23 ,  33 , after removing the plugs from the latter. 
     At a subsequent lubricant monitoring step, some lubricant can be successively diverted from each of the branches  10 ,  20 ,  30  through line  200  of the lubricant monitoring system  100  by selecting each corresponding inlet connection  101 ,  102 ,  103  and outlet connection  111 ,  112 ,  113  with the selective inlet valve  120  and selective outlet valve  160  optionally controlled by the control unit  170 . The lubricant circulating through line  200  can therefore pass through the first analysis device  130  of which the different sensors can separately detect metal and non-metal solid particles of different sizes, and the second analysis device  140  of which the different sensors can detect the properties of the lubricant such as colour, turbidity, electrical conductivity, viscosity, temperature and/or pressure, as well as possible sounds and/or vibrations. The data captured by the sensors of the analysis devices  130 ,  140  at this monitoring step can be transmitted to the control unit  170  for processing, analysis, storage and/or transmission via the communication device  180 . In addition, at this monitoring step, the electric powering device  190  can electrically power the different other members of the lubricant monitoring system  100  with electrical power drawn by the power extraction device  150  on the lubricant flow passing through it and/or recovered from the power storage device  155 . 
     When it is decided to finalize monitoring of the lubricant, the lubricant monitoring system  100  can be uninstalled by separating each inlet connection  101 ,  102 ,  103  and each outlet connection  111 ,  112 ,  113  of the lubricant monitoring system  100  from the respective upstream branches  12 ,  22 ,  32  and downstream branches  13 ,  23 ,  33 , and shutting off the latter with the plugs. 
     Although the present invention has been described with reference to specific examples of embodiment, it is obvious that different modifications and changes can be made to these examples without departing from the general scope of the invention such as defined by the claims. Also, individual characteristics of the different described embodiments can be combined in additional embodiments. The description and drawings must therefore be construed as illustrative rather than restrictive.