GB2578602A

GB2578602A - Machine condition monitoring

Info

Publication number: GB2578602A
Application number: GB1817806.1A
Authority: GB
Inventors: Reddyhoff Thomas; Hartinger Markus
Original assignee: Imperial Innovations Ltd
Current assignee: Ip2ipo Innovations Ltd
Priority date: 2018-10-31
Filing date: 2018-10-31
Publication date: 2020-05-20
Also published as: GB201817806D0

Abstract

Inline lubricating fluid quality monitoring device 330 comprises first and second contact surfaces 302, 304 which are urged together and in cyclical relative motion. Fluid (e.g. oil) from a lubricated machine component (which, in an aspect, is operating) received at inlet 310 is delivered to between the surfaces. A sensor detects a parameter (e.g. friction, vibration, particulates, viscosity) indicating the quality of the fluid between the surfaces. The cyclical relative motion may be oscillating, rolling and/or sliding. The force may be normal to a contact plane defined by the surfaces, the relative motion having a component in the plane. The geometry of the surfaces may simulate those of the machine component; the relative motion and force urging the surfaces together may simulate contact loading conditions. The device may be located in a machine lubrication system, but remote from the component. Fluid may flow continuously for continuous quality monitoring.

Description

Machine Condition Monitoring [0001] This invention relates to machine condition monitoring. In particular, the invention relates to machine condition monitoring through an inline lubricating fluid quality monitoring device for continuously monitoring the quality of a lubricating fluid of the machine. The invention further relates to an associated method of inline monitoring of lubrication fluid quality.

BACKGROUND

[0002] Monitoring lubricating fluid quality is important because a majority of machinery failures initiate in lubricated sliding contact surfaces in machine elements -for example in components such as gears, bearings, pistons and the like, within machines such as combustion and electrical engines, and gearboxes for wind turbines or gas and water turbines, all of which are typically lubricated with specialised oils. The condition of the lubricating oil can be indicative of the condition of the machine, for example through the presence of particulates in the oil indicating the wearing of one or more surfaces in the machine. Accordingly, by monitoring the quality of the oil, it is possible to predict necessary maintenance schedules or the expected remaining life-span of a machine or a particular component within it. This is becoming more important as machines are being designed to have longer service intervals and less frequent oil changes, meaning that the oil within will undergo a greater number of heat cycles and be more exposed to contamination from fuels and other particulates, be more prone to degradation (for example of additives within the oil composition) and be more susceptible to acid build-up. Accordingly, monitoring for the current condition of the oil is increasingly important.

[0003] It is known to measure properties of an oil (such as viscosity, impurity concentration, particle hardness and size distribution) inline, as it is circulating in a machine under test. This is illustrated schematically in Figure 1, in which a machine 20 is lubricated by a circulating oil system 30 containing oil 10. The oil 10 flows past a sensor 40, such as a paired ultrasonic transducer 42 and receiver 44 for detecting the presence of particulates in the oil. This type of arrangement has the advantage that oil quality can be monitored in real time. A significant disadvantage is that it is difficult to link the resulting bulk oil measurements to the performance of the machine or, more particularly, to the performance of specific wear surfaces within that machine, because the detection takes place on the bulk oil and remotely from the contact surfaces intended to be monitored, so has limited use in predicting the machine condition. By way of example, if the machine under test is an internal combustion engine, the properties of the oil, including the presence of any impurities can be detected, e.g. through ultrasonic or optical sensors or chemical analysis and the like, and this can be indicative of some wear within the engine, but that cannot readily be associated with any particular component in the engine, such as the pistons or the cam shaft.

[0004] It is also currently known to research wear mechanisms and lubricant performance through offline simulation, in which specialised laboratory test instruments ('tribometers') are used to characterise the friction and wear behaviour of sliding contact surfaces, which represent those of machine components found in machines. These rigs are designed to produce contact surfaces which operate under highly controlled conditions (by loading and sliding two specimen surfaces together) and allow easy access for measurement techniques used to characterise the behaviour.

[0005] These type of test instruments and methodologies are used to understand how machines fail in general terms and how lubricants perform -especially for the testing of new lubricant formulations, but are not used to monitor the performance of a particular machine. The companies PCS Instruments, Bruker and Anton-Paar all market such test rigs.

[0006] For example, PCS Instruments, produces the ETM (Extreme Pressure Traction Machine), USV (Ultra Shear Viscometer), MTM (Mini Traction Machine), MPR (Micro Pitting Rig) and HFFR (High Frequency Reciprocating Rig) instruments. Each of these instruments includes an approximated reproduction of the type of sliding contact surface that is being tested and the conditions under which it would be operated. Different contact geometries and relative motions are used to replicate or simulate different applications in order to match the operating and testing conditions as closely as possible to those of the actual sliding surfaces that are under test. For example, the ETM and MTM rigs each replicate a bearing contact surface, wherein the rig includes a spherical contact surface pressed under closely controlled load into contact with an opposing spinning disc contact surface.

[0007] An example of such a rig 100 is schematically illustrated in plan view in Figure 2. The rig 100 comprises a chamber 102 in which is located a disc 104 that is mounted for rotation about a vertical axis 106. A sphere 108 having a spherical contact surface 108' is positioned within a housing 110 above the disc 104 and pressed under closely controlled load (see arrow F) into contact with an opposing disc contact surface 104' on the periphery of the disc 104. A batch of lubricating fluid (oil) 10 is poured from a container 12 into the chamber 102 and fills the space between the contact surfaces 104', 108' to lubricate that contact. As the disc 104 is spun (see arrow A), the sphere 108 is caused to rotate in an opposite direction within its housing 110 (see arrow B). Sensors detect vibrations of and forces between the contact surfaces, indicative of the performance of the oil under the particular conditions, and therefore its suitability for that type of application. In this example, a force sensor 120 detects the amount of force F applied in the direction normal to the contact surfaces 104',108', and respective vibration sensors 122, 124 detect the vibrations of the respective contact surfaces 104', 108'. Each of the sensors is in communication with a processor 180 to receive and analyse signals from the sensors 120, 122, 124 to make a determination as to the quality of the oil 10 on the basis of those signals. In some such rigs, one of the contact surfaces may be transparent and an optical sensor may be used to detect for contaminants in the oil.

[0008] To replicate a piston/cylinder interface, a test rig 200 with a linear reciprocating motion could be used, for example as illustrated in schematic side elevation view in Figure 3. In Figure 3, a lower contact surface 202 is held stationary whilst an upper contact surface 204 is reciprocated (arrow C) in a plane parallel to the opposing contact surfaces under a normal force F. As with the example illustrated in Figure 2, sensors detect vibrations of and forces between the contact surfaces 202, 204, indicative of the performance of the oil 10 under the particular conditions, and therefore its suitability for that type of application. In this example, a force sensor 220 detects the amount of force F applied in the direction normal to the contact surfaces 202, 204, and respective vibration sensors 222, 224 detect the vibrations of the respective contact surfaces 202, 204. Each of the sensors is in communication with a processor 280 to receive and analyse signals from the sensors 220, 222, 224 to make a determination as to the quality of the oil 10 on the basis of those signals.

[0009] It is also known to apply measurement techniques (e.g. vibration or acoustic sensors) directly to a sliding machine element (e.g. a bearing, gear, or piston contact) within a machine as it is running in order to monitor its performance and predict when failure will occur/replacement is needed. A significant difficulty with this approach is that sliding contacts in machines are often very inaccessible (they can be very small and often move at high speed), it can be difficult to place sensors in position without interfering with machine performance, and the operating conditions are frequently unconducive to accurate measurements anyhow, due for example to high temperatures and vibrations within the machine under test which make it difficult to isolate/identify the signals emanating from the contact surfaces from those more generally resulting from operation of the machine and the surrounding environment. As a result, only severe failures can typically be detected with such techniques, which can be too late for effective maintenance or prevention.

[0010] An objective of the present invention is to overcome these shortcomings by providing a way to test the quality of a lubricant as it circulates in a machine under test, in conditions which closely approximate those of specific sliding contact surfaces within the machine, to better monitor specific machine condition and lubricant performance in real time.

BRIEF SUMMARY OF THE DISCLOSURE

[0011] In accordance with a first aspect of the present invention, there is provided an inline lubricating fluid quality monitoring device comprising: an inlet for receiving lubricating fluid from a lubricated machine component; first and second contact surfaces urged together and in cyclical relative motion when in use, wherein the lubricating fluid is delivered from the inlet to between the contact surfaces; and at least one sensor for detecting one or more parameters indicative of the quality of the lubricating fluid between the first and second contact surfaces.

[0012] Advantageously, the at least one sensor is thus able to detect the quality of the lubricating fluid as affected by a contact surface interaction that simulates in some way that of real contact conditions of the machine component that is under test. This monitoring can be continuous, real-time monitoring that takes place whilst the machine component is in operation.

[0013] The cyclical relative motion may comprise at least one of: oscillating; rolling; and sliding. Combinations of these relative motions are also possible. Accordingly, the simulated motion of the contact surfaces may be tailored to correspond to the specific kinds of movements found in the contact surfaces of the specific machine component of interest.

[0014] The first and second contact surfaces may define a plane of contact, the surfaces being urged together by a force normal to the plane of contact, and the relative motion having at least a component parallel to the plane of contact. Thus, the relative movement of the contact surfaces is under a controlled load and defines a relative sliding motion.

The size of the load may be controlled to replicate the loads experienced in the specific machine component of interest.

[0015] The first and second surfaces may have geometries that simulate surfaces of the machine component in contact with the lubricating fluid. Simulation of the surfaces of the machine component may comprise an exact replication of those surfaces: their materials; their topographies, etc., or may comprise a scaled-down version of the same, or may comprise a mere approximation that represents physical characteristics of those surfaces, for example using similar but not identical topographies, and/or similar but not identical materials.

[0016] The device of any preceding claim, wherein the first and second surfaces are urged together and are moved relative to one another in simulation of contact loading conditions of wear surfaces of the machine component. Thus, for example, optionally, the size of any load applied to urge the contact surfaces of the device together may be scaled to suit the relative dimensions of those contact surfaces in the device as compared to the contact surfaces of interest in the machine component. Alternatively or additionally, the speed of relative motion may be adjusted to account for the differences in scale between the contact surfaces of the device and those of interest in the machine component. Thus, in some embodiments, the simulation may be achieved by controlling one or more of: the size of the normal force; the contact pressure; the relative speed of the contact surfaces; the frequency of reciprocation; the separation distance between the contact surfaces (i.e. the film thickness of the lubricating fluid between those surfaces); and the lambda ratio (the relationship between minimum film thickness and composite surface roughness of the contact surfaces: A = h / a*, where h = the film thickness or separation distance between the contact surfaces, and a*.")(012+ 022), with n and 02 being the respective surface roughness values for the first and second contact surfaces). In particular, the contact pressure and/or lambda ratio may be matched to that of the contact surfaces of the machine component of interest.

[0017] The device may further comprise an outlet for returning the lubricating fluid to the machine component. Thus, the device can easily be incorporated into a lubrication system of the machine. Accordingly, in certain embodiments, the device is for location in a machine lubrication system, wherein the inlet is in fluid connection with the machine lubrication system downstream of the machine component, and the outlet is in fluid communication with the machine lubrication system upstream of the machine component.

The lubricating fluid may continuously flow within the machine lubrication system when in operation and the at least one sensor may be for continuously monitoring the quality of the lubricating fluid. It will be appreciated that the monitoring may be made at suitable intervals, periodic or otherwise.

[0018] The device may be located remote from the machine component. That is to say, the device is located a sufficient distance away from the machine component and/or is sufficiently shielded from the effects of physical disturbances emanating from the machine component or a greater machine in which it is incorporated, through damping or shielding mechanisms, so as to be isolated from any such physical disturbances (e.g. vibrations, heat), whereby measurements taken at the device are not unduly affected by such disturbances.

[0019] The at least one sensor may comprise one or more of: force, vibration, acoustic, electromagnetic (including optical), electrical (e.g. resistance, inductance, capacitance, etc.) and temperature sensors, and any combination thereof, for detecting one or more of: the friction forces involved in the sliding contact, the vibration of the first contact surface and the vibration of the second contact surface, the presence of particulates in the lubricant, the viscosity of the lubricant, impurity concentration within the lubricant, and particle hardness/size/distribution within the lubricant. The device may further comprise a processor configured to receive data signals from the at least one sensor and to process those signals to determine a lubrication fluid quality metric.

[0020] The lubricating fluid typically comprises oil.

[0021] According to a second aspect of the invention, there is provided a method of inline monitoring of lubrication fluid quality comprising: providing a lubrication fluid quality monitoring device in fluid communication with an operative machine component, the device including first and second contact surfaces and at least one sensor; receiving a supply of the lubrication fluid from the operative machine component and delivering the lubrication fluid to between the contact surfaces; urging the first and second contact surfaces towards one another with a normal force and cyclically moving the first and second contact surfaces relative to one another; and detecting, using the at least one sensor, one or more parameters indicative of the quality of the lubricating fluid between the first and second contact surfaces.

[0022] The method may be carried out using a device according to the first aspect of the invention. The first and second contact surfaces may be urged together and be moved relative to one another in simulation of contact loading conditions of wear surfaces of the machine component.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of a known system for real-time monitoring of oil quality within an operative machine lubrication system; Figure 2 is a schematic plan view of a first kind of known test instrument for simulating contact conditions of a rolling machine component to test how an oil performs under those conditions; Figure 3 is a schematic side elevation view of a second kind of known test instrument for simulating contact conditions of a reciprocating machine component to test how an oil performs under those conditions; Figure 4 is a schematic side elevation view of an oil quality monitoring device according to the invention; and Figure 5 illustrates, schematically, where a device of the type shown in Figure 4 may be located within a machine's lubrication system.

DETAILED DESCRIPTION

[0024] One embodiment of an inline lubricating fluid quality monitoring device 300 according to an aspect of the invention will be described with reference to the schematic illustration of Figure 4. For simplicity, the invention is described by reference to the lubricating fluid in the form of an oil, but the skilled person would understand that the invention could be used in conjunction with other lubricating fluids.

[0025] The device 300 is in fluid communication with a lubricating system 30 of a machine 20 for monitoring the condition of the lubricating fluid 10 within the system, which can be indicative of the performance of the machine 20. The device 300 can have general applicability to any kind of lubricated machinery, including for individual machine components within a larger machine, such as bearings or pistons within an engine, or gears within a gearbox. As such, it should be understood that references to a machine and those to a machine component are interchangeable in this context. The lubricating system 30 comprises one or more conduits to transport the lubricating fluid (oil) 10, typically under pressure -e.g. induced by a pump (not shown), from an outlet 32 of the machine back round to an inlet 34 of the machine 20, typically during operation of the machine. The device 300 can be installed inline at any suitable location within that lubricating system 30, provided it is sufficiently physically spaced from the machine 20 (see separation S) not to be affected by operation of the machine, as will be explained in greater detail below and with reference to Figure 5.

[0026] The device 300 is for replicating or in some way simulating conditions found within the machine or a particular component part of that machine -in particular, conditions at or in the vicinity of lubricated surfaces, which would typically comprise opposed wear surfaces -i.e. those surfaces that may come into contact during relative sliding movements in operation of the machine.

[0027] The device 300 thus includes a first contact surface 302, here represented in the form of a simple planar surface, and a corresponding opposed second contact surface 304, here represented in the form of a sphere. The first and second contact surfaces 302, 304 are arranged for cyclical relative motion with respect to one another, as will be described in greater detail below. The first and second surfaces are urged together under a force F. The first and second contact surfaces 302, 304 may define a plane of contact P and the force F may be applied in a direction normal to the plane of contact P. The first and second surfaces 302, 304 are contained within a housing 330.

[0028] Typically, the relative motion between the first and second contact surfaces 302, 304 is parallel to the plane of contact P, or at least has a component parallel to that plane of contact, as represented by the double-headed arrow D in Figure 4. The cyclical relative motion of the first and second contact surfaces 302, 304 may take the form of at least one of: oscillating; rolling; and sliding. Combinations of these relative motions are also possible. Accordingly, the simulated motion of the contact surfaces 302, 304 may be tailored to correspond to the specific kinds of movements found in the contact surfaces of the specific machine component of interest. This may take the form of one of the surfaces being held stationary whilst the other is moved relative to it, or both surfaces 302, 304 may move; optionally both being actively driven or by one of the surfaces being actively driven whilst the other of the surfaces is passively driven under the influence of the actively driven surface. The skilled person would readily be able to conceive of suitable actuation/drive systems to implement such relative motion.

[0029] The first and second contact surfaces 302, 304 may have geometries that simulate surfaces of the machine component in contact with the lubricating fluid 10. Simulation or recreation of the surfaces of the machine component 20 may comprise an exact replication of those surfaces: their materials; their topographies, etc., or may comprise a scaled-down version of the same, or may comprise a mere approximation that represents physical characteristics of those surfaces, for example using similar but not identical topographies, and/or similar but not identical materials.

[0030] The device 300 includes a fluid inlet 310 in fluid communication with the machine's outlet 32, to deliver oil from the machine to between the contact surfaces 302, 304 in the device. The device 300 typically also includes an outlet 312 in fluid communication with the machine's inlet 34 -although in some embodiments the oil drained from the device 300 may not be returned to the machine 20. Accordingly, in certain embodiments, the inlet 310 to the device 300 is downstream of the outlet 32 of the machine component, and the outlet 312 is upstream of the inlet 34 of the machine component.

[0031] The device 300 further includes one or more sensors that detect parameters indicative of the quality of the oil between the contact surfaces 302, 304 as those surfaces are cyclically moved relative to one another. The sensors may take the form of one or more of a force sensor (e.g. strain gauges with torsion rod) 320 to measure friction force, a first vibration sensor 322 associated with the first contact surface 302 to detect vibrations of that first contact surface, and a second vibration sensor 324 associated with the second contact surface 304 to detect vibrations of that second contact surface. More generally, the at least one sensor may comprise one or more of: force, vibration, acoustic, electromagnetic (including optical), electrical (e.g. resistance, inductance, capacitance, etc.) and temperature sensors, and any combination thereof, for detecting one or more of the friction forces involved in the sliding contact, the vibration of the first contact surface 302 and the vibration of the second contact surface 304, the presence of particulates in the lubricant 10, the viscosity of the lubricant 10, impurity concentration within the lubricant 10, and particle hardness/size/distribution within the lubricant 10.

[0032] Each of the sensors 320 to 324 generates signals in dependence on the detected parameters and those signals can be transmitted to a processor 380. The processor 380 can thus receive inputs from any or all of the sensors and process the data from those signals in order to make a holistic determination as to the condition of the oil. This determination as to the condition of the oil may take the form of a lubrication fluid quality metric.

[0033] Preferably, the first and second surfaces 302, 304 are urged together and are moved relative to one another in simulation of contact loading conditions of wear surfaces of the machine component 20. Thus, for example, optionally, the size of any load F applied to urge the contact surfaces 302, 304 of the device 300 together may be scaled to suit the relative dimensions of those contact surfaces 302, 304 in the device as compared to the contact surfaces of interest in the machine component 20. The size of the load F may be controlled to replicate the loads experienced in the specific machine component of interest. This may be a fixed load for a given test, or the load may be varied as the testing is performed. Alternatively or additionally, the speed of relative motion may be adjusted to account for the differences in scale between the contact surfaces 302, 304 of the device and those of interest in the machine component 20.

[0034] Overall, the objective of the simulation within the device 300 is to replicate the regime of lubrication as found at the relevant part of the machine component 20 of interest -i.e. whether and to what extent the lubrication is mixed boundary or full film regime. Thus, in some embodiments, the simulation may be achieved by controlling one or more of: the size of the normal force F; the contact pressure; the relative speed of the contact surfaces 302, 304; the frequency of oscillation/reciprocation; the separation distance between the contact surfaces (i.e. the film thickness of the lubricating fluid 10 between those surfaces 302, 304); and the lambda ratio (the relationship between minimum film thickness and composite surface roughness of the contact surfaces: A = h / a, where h = the film thickness or separation distance between the contact surfaces 302, 304, and a*= N'(0i2+ 022), with al and a2 being the respective surface roughness values for the first and second contact surfaces). In particular, the contact pressure and/or lambda ratio may be matched to that of the contact surfaces of the machine component 20 of interest.

[0035] Advantageously, the at least one sensor 320 to 324 is thus able to detect the quality of the lubricating fluid 10 as affected by a contact surface interaction that simulates in some way that of real contact conditions of the machine component that is under test.

This monitoring can be continuous, real-time monitoring that takes place whilst the machine component 20 is in operation. The oil 10 may continuously flow within the machine lubrication system 30 when in operation and the at least one sensor 320 to 324 may be for continuously monitoring the quality of the oil. It will be appreciated, however, that the monitoring may be made at suitable intervals, periodic or otherwise. One way to carry out such periodic testing would be to have the device 300 located in a bypass branch of the lubrication system 30, under valve control, as shown in Figure 5.

[0036] It is important for the device 300 to be located a sufficient distance away from the machine component 20 and/or to be sufficiently shielded from the effects of physical disturbances emanating from the machine component or a greater machine in which it is incorporated, through damping or shielding mechanisms, so as to be isolated from any such physical disturbances (e.g. vibrations, heat), whereby measurements taken at the device are not unduly affected by such disturbances.

[0037] Figure 5 illustrates some non-limiting, representative locations X and Y for the device 300 in the context of a lubrication system for an internal combustion engine 400.

Position X has the device 300' located within an oil pan sump 402. In such a location, the inlet 310 can be situated to be permanently immersed in oil 10 within the sump 402, so there is a ready supply of oil to the space between the first and second contact surfaces 302, 304. Oil that has passed between the contact surfaces is ejected from the outlet 312 back into the sump 402. The intake of oil into the device 300' may be under valve control.

The device 300' may be operated continuously or periodically. In position Y, the device 300" is in a bypass branch of the lubrication system, connected thereto by first and second valves 404, 406 respectively controlling the flow to/from the inlet 310 and the outlet 312 of the device. As such, the flow of oil 10 into and out of the device 300" can be controlled and can be selected to be continuous (valves always open) or, more preferably, periodic (valves intermittently open). Where the flow of oil is periodic, the contact surfaces 302, 304 are moved relative to one another only when the valves 404, 406 are open (or a fresh batch of oil has been admitted to the device 300" under suitable valve control). Likewise, operation of the sensors 320 to 324 can be limited to when the surfaces 302, 304 are in relative motion. In each of these positions, the device 300 is effectively isolated from the effects of heat and vibration emanating from the engine 400 itself.

[0038] A key aspect of this invention is that it produces an artificial contact that is not part of the machine's function. This gives it the advantage (over conventional means of monitoring lubricated contacts) that the device 300 can be located anywhere within or adjacent to the machine 20, provided oil 10 can be supplied to it. Unlike many conventional condition monitoring devices, it does not need to be located near to the actual sliding components of the machine that are problematic in terms of heat, noise, motion, lack of space. Such a device 300 could potentially have a much earlier detection of changes/problems in the machine 20 because it can more readily determine a causal link between the condition of the oil 10 and the contact conditions within the machine 20 under test. A robust calibration procedure based on highly sensitive lab-equipment is possible to ensure that the determinations made by the device 300 are accurate.

[0039] In summary, the invention provides a lubricant quality measuring device using two bodies loaded together in relative motion and a sensor system capturing, force, electromagnetic, optical, acoustic and vibrations emissions. The idea is to produce an artificial rubbing contact, but have this device located with a machine (typically a car) and have it fed by oil from the machine (i.e. it is an inline device).

[0040] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0041] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0042] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

CLAIMSAn inline lubricating fluid quality monitoring device comprising: an inlet for receiving lubricating fluid from a lubricated machine component; first and second contact surfaces urged together and in cyclical relative motion when in use, wherein the lubricating fluid is delivered from the inlet to between the contact surfaces; and at least one sensor for detecting one or more parameters indicative of the quality of the lubricating fluid between the first and second contact surfaces.
2. The device of claim 1, wherein the cyclical relative motion comprises at least one of: oscillating; rolling; and sliding; or combinations of the aforemetioned.
3. The device of claim 1 or claim 2, wherein the first and second surfaces define a plane of contact, the surfaces being urged together by a force normal to the plane of contact, and the relative motion having at least a component parallel to the plane of 15 contact.
4. The device of any preceding claim, wherein the first and second surfaces have geometries that simulate surfaces of the machine component in contact with the lubricating fluid.
5. The device of any preceding claim, wherein the first and second surfaces are urged together and are moved relative to one another in simulation of contact loading conditions of wear surfaces of the machine component.
6. The device of any preceding claim, further comprising an outlet for returning the lubricating fluid to the machine component.
7. The device of claim 6, wherein the device is for location in a machine lubrication system, the inlet in fluid connection with the machine lubrication system downstream of the machine component, and the outlet in fluid communication with the machine lubrication system upstream of the machine component.
8. The device of claim 7, wherein the lubricating fluid continuously flows within the machine lubrication system when in operation and the at least one sensor is for continuously monitoring the quality of the lubricating fluid.
9. The device of any preceding claim, located remote from the machine component.
10. The device of any preceding claim, wherein the at least one sensor comprises one or more of: force, vibration, acoustic, electromagnetic (including optical), electrical (e.g. resistance, inductance, capacitance, etc.) and temperature sensors, and any combination thereof, for detecting one or more of: the friction forces involved in the sliding contact, the vibration of the first contact surface and the vibration of the second contact surface, the presence of particulates in the lubricant, the viscosity of the lubricant, impurity concentration within the lubricant, and particle hardness/size/distribution within the lubricant.
11. The device of claim 10, further comprising a processor configured to receive data signals from the at least one sensor and to process those signals to determine a lubrication fluid quality metric.
12. The device of any preceding claim, wherein the lubricating fluid comprises oil.
13. A method of inline monitoring of lubrication fluid quality comprising: providing a lubrication fluid quality monitoring device in fluid communication with an operative machine component, the device including first and second contact surfaces and at least one sensor; receiving a supply of the lubrication fluid from the operating machine component and delivering the lubrication fluid to between the contact surfaces; urging the first and second contact surfaces towards one another with a normal force and cyclically moving the first and second contact surfaces relative to one another; and detecting, using the at least one sensor, one or more parameters indicative of the quality of the lubricating fluid between the first and second contact surfaces.
14. The method of claim 13 using the device of any of claims 1 to 12.
15. The method of claim 13, wherein the first and second surfaces are urged together and are moved relative to one another in simulation of contact loading conditions of wear surfaces of the machine component.