Patent Application
20240210294
The present invention is directed at a method to evaluate the wear depth of non-metallic parts. In particular, non-metallic parts formed of polymeric material with selected amounts of metallic particles through the part thickness. Upon wear of the polymeric material the metallic particles are released which can be detected by inductively coupled plasma atomic emission spectroscopy.
Operating machinery typically have relatively critical parts which, when worn, will lead to downtime and expense. Regular maintenance is therefore essential to maintain operations, but maintenance expense in itself can be relatively costly and still lead to downtime, although less than what is experienced for a full failure situation.
In some situations, it is not typically practical to undertake invasive maintenance on a regular basis and therefore in lubricated systems, analysis is often made of the oils and greases associated with metal machinery or engine operations. For example, regular monitoring of metals in oils can diagnose engine wear so that preventive maintenance procedures can be performed, increasing equipment reliability.
Inductively coupled plasma atomic emission spectroscopy (ICP-AES) has been reported as an efficient technique to detect the parts per million (ppm) of metals in oil samples and the metal content can be mapped to the different components made of the metals in the machinery.
A method of evaluating wear depth of a non-metallic part comprising forming a non-metallic part with a plurality of layers wherein selected amounts of metal particles are present in said layers, exposing said non-metallic part to wear in a lubricating environment containing lubricant, and determining the metal particle concentration in said lubricant and identifying a wear depth in said non-metallic part.
A method of evaluating wear depth of a non-metallic part comprising forming a non-metallic part including one or a plurality of upper layers and one or a plurality of lower layers, embedding in said one or plurality of upper layers a first metal composition (M1), embedding in said one or plurality of lower layers a second metal composition (M2) that is different from M1, exposing said non-metallic part to wear in a lubricating environment containing lubricant, and identifying the presence of metal particles M1 and M2 in said lubricant and a wear depth of said non-metallic part.
ICP-AES analysis is reference here to a technique for determining metal constituents of metal particulate that is suspended in a liquid (e.g. a lubricating oil). The technique is based upon generation of an inductively coupled plasma utilizing RF energy. The liquid samples may be converted into an aerosol and injected into a plasma. As the sample enters the plasma, it volatilizes, atomizes, excites and ultimately emits photon characteristic of the wavelengths of the metals present in the sample. The intensity of the emission at characteristic wavelengths is used to determine the concentration of a metal element present in the sample. The plasma is typically supported by argon gas but other gases may be employed.
It is contemplated herein that non-metallic parts, whose wear characteristics would be considered important to monitor, may now be made of polymeric material with selected amounts of embedded metallic particles. The metallic particles may preferably have a particle size in the range of 1.0 μm to 999.0 μm, including all individual values and ranges therein. The metallic particles that are therefore to be embedded within the polymeric material are preferably selected from a metallic material that is different than other metals that are present in the system. For example, in an engine where there is already steel, copper, and/or lead, one would preferably select aluminum in particulate form for selectively loading in the polymer whose wear characteristics within the engine are to be evaluated.
Preferably, the polymeric material of the part whose wear characteristics is to be evaluated is now formed such that the density of the metal particle impregnation is selectively varied and increased from the surface down to a selected lower layer(s). It is contemplated that the number of layers in the polymeric material with increasing density of metallic particles in each respective layer may preferably fall in the range of 2-15 layers. It is also contemplated that the formation of such a multi-layered polymeric material component with increasing density of metallic particles in each respective layer may be conveniently achieved by additive manufacturing or extrusion
For example, the density of metallic particles in the polymer material at the surface down to a thickness of 1.0 mm may be zero, at a thickness of greater than 1.0 mm to 2.0 mm the density of the metallic particles is equal to D1, at a thickness of greater than 2.0 mm to 3.0 mm the density of the metallic particles is equal to D2, and at a thickness of greater than 3.0 mm to 4.0 mm the density of the metallic particles is equal to D3, and at a thickness of greater than 4.0 mm to 5.0 mm the density of the metallic particles is equal to D4. In this situation, D2>D1, D3>D2 and D4>D3.
When such polymeric material is subject to wear in lubricated engine environment, the lubricant (oil) can then be conveniently collected and analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). More specifically, one may utilize ASTM D5185 (2018), Determination of Additive Elements, Wear, Metals and Contaminants in Used Lubricating Oils and Determination of Selected Elements in Based Oils by ICP-AES. It is therefore contemplated that one may monitor and detect the presence of the metal particle density level and then map that to the density levels D1, D2, D3, and D4 noted above. In such manner, the user is now made aware of the relative wear depth of the polymeric material at issue as well as the wear of metallic components of the engine under consideration.
By way of one more specific example, in the case of chain tensioner made of polymeric material, used to maintain the tension within the roller timing chain systems of a combustion engine, it is contemplated that such chain guide could be made of eight layers of polymeric material. In such a chain tensioner, it is preferably that the tensioner should be replaced when the wear depth has reached 50% of the original depth. Accordingly, the density of the metallic particles in the first three (3) layers may be set relatively lower than the density in layers 4, 5, 6, 7 and 8. Upon use of such chain tensioner made of polymeric material, in a lubricated environment, the lubricant (oil) can be collected and analyzed according to ASTM D5185 (2018). Upon identification of the metal particle density levels associated with layers 4, 5, 6, 7 or 8, one may readily determine that the tensioner is to be replaced.
Moreover, it is contemplated herein that the polymeric material of the part whose wear characteristics is to be evaluated may also be formed such that the composition of the metal particle impregnation is selectively varied from the surface down to one or a plurality of selected lower layer(s). For example, the metal particles impregnated in one or more of the upper layers down from the surface may comprise a first metal composition (M1) and the metal particles impregnated in one or more of the lower layers may comprise a second metal composition (M2), where the compositions of M1 and M2 are different. For example, composition M1 may preferably be steel and composition M2 may preferably be aluminum. Accordingly, in a lubricated environment, the release of the first metal composition (M1) due to wear followed by analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES) is contemplated to indicate to the user that there is an acceptable amount of wear. However, upon further wear and release of the second metal composition (M2), ICP-AES analysis can then indicate an unacceptable level of wear or that some critical wear point has been reached to signify that the non-metallic part at issue must be promptly replaced.
In addition, it can be appreciated from the above that one may utilize, for example, a gradient of different metal compositions (e.g. M1, M2, M3 . . . . Mx) in the particles that are selectively and individually embedded in the plurality of layers of the non-metallic part down from the surface. For example, particles with metal composition M1 embedded in one or more of the initial layer(s) down from the surface, particles with metal composition M2 embedded in one or more of the intermediate layer(s) down from the surface, and particles with metal composition M3 embedded in one or more of the lower layer(s) down from the surface. In such a manner, and upon wear of the non-metallic part in a lubricating environment and release of a particular metal particle composition M1, M2 or M3, it is contemplated that one may assign a specific gradient type level of wear to the part whose wear analysis is under evaluation.
The polymeric materials herein that are contemplated for use include thermoplastics and thermosets. As alluded to above, additive manufacturing may be employed to produce polymeric parts with a plurality of layers have varying density distribution of the metallic particles within the individual layers. The polymer may more preferably be selected from acrylonitrile-butadiene styrene (ABS), polyethylene terephthalate (PET), polycarbonate, polyetheretherketones (PEK), polypropylene, polyamides, fluorocarbon polymers (e.g., polytetrafluroethylene or PTFE), epoxy resins and/or polyurethanes.
As may now be appreciated, the present invention relates to method of evaluating wear depth of a non-metallic part comprising forming a non-metallic part with a plurality of layers wherein selected amounts of metal particles of the same or different composition are present in the layers. This is then followed by exposing the non-metallic part to wear in a lubricating environment containing lubricant. One may then determine the metal particle concentration and/or metal composition in the lubricant and identify a wear depth in the non-metallic part.
| Number | Date | Country | |
|---|---|---|---|
| 63477247 | Dec 2022 | US |
