placed in context of the recently approved ASTM Practice E alternative means of executing this ASTM Practice, its objective being to minimize . E – Download as PDF File .pdf), Text File .txt) or read online. Referenced Documents ASTM Standards:3 D Test Method for Kinematic Viscosity. improper air/fuel ratio. There are test methods for laboratory grade FTIR measurement as well as for portable field testing. ASTM E describes the standard.
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This creates a huge issue for some engines, mainly natural gas engines aetm they operate at higher combustion temperatures and therefore high Nitrous Oxides NOx are formed. Referenced Documents sstm separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A asmt discussion of distribution profile analysis and alarm limit determination is beyond the scope of this practice. If the population of machines is very large, less than one overhaul period may be sufficient. For example, infrared spectroscopy cannot determine wear metal levels or any other type of elemental analysis.
Other techniques based on computer fitting and removing the regular sine wave pattern in the absorbance spectrum, using cell windows with antireflective coatings, or slightly 9wedging9 the cell windows.
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Others are calibrated, including diesel fuel, gasoline, water, and glycol. Such limits should be established in conjunction with advice and guidance from the machinery manufacturer and maintenance group. It is better to make f2412 choice of lubricant type and use it consistently if the oil type is not known. Contaminants monitored include water, soot, ethylene glycol, fuels and incorrect oil.
Water is measured as depicted in Fig. Adequate mixing is necessary to obtain valid results. Water is detected using a broad feature, centered around cm-1, that is caused by stretching of the hydrogen-bonded hydroxyl -OH group.
Because the soot absorbance obtained is a measure of the amount of tilt in the spectral baseline, a correction should be applied to the data to account for the contribution of the transmission cell to the baseline tilt if the background is taken without the cell in the beam path. In the case where salt windows are used, when oil is introduced into the cell the fringe pattern is made much weaker because the refractive index of the salt window is relatively close to that of an oil sample.
Sequential samples over the course of the overhaul period are more likely to yield normally distributed results. The materials leading to this feature are nitrate esters. Instead the peaks at and cm-1 are used to confirm the presence of glycol.
Atsm infrared data generated by this practice is typically used in conjunction with other testing methods. This band is a fairly specific measure of over basing additive consumption and directly relates to the TBN assay for engine oils. Originally approved in An independent test, such as viscosity change, flash point, or gas chromatography can be used to confirm an indication of fuel presence in the FT-IR spectrum of the oil.
The effective particle size is determined by the nature of the combustion system and the dispersants in the oil. In addition, multiple frequency distributions may also be required and are not given here.
These different approaches are equally valid for trending but will produce results aztm differ numerically. Once again however, water adtm of this magnitude will condemn the lubricant irrespective of the actual breakdown level. Therefore, when glycol is present, water cannot be reliably quantified using the FT-IR measurement. As seen below in Fig.
The footnotes to Table A2.
Under severe conditions of lubricant degradation, this band will begin to overlap and contribute to the integrated water measurement area. The population should include a minimum of several hundred results for meaningful statistical analysis.
However, the converse is not true since glycol has other spectral features that are used for detection and quantification.
ASTM E – standard practice for Condition Monitoring of Used Lubricants by FT-IR Spectrometry.
In these systems, the most common parameters measured are water contamination and oxidative breakdown of the oil, which are presented in Table A1.
The broadness of the peak is a result of the wide variety of materials present. Since no single product is formed, standard materials are not available to generate the calibration curves needed to relate absorbance to concentration. The baseline for carbonyl oxidation measurement, referred to as oxidation, is taken at cm-1 and the maximum peak height between and cm-1 is determined.