SU68986A1 - The method of determining the quality of lubricating oils according to the degree of their contamination - Google Patents

Description

Numerous studies of the aging of various lubricating oils in various engines have shown that the basis of aging of oils is not so much the chemical change of the entire mass of operating lubricating oil, but its contamination both with decomposition products of a part of oil and fuel, and other impurities (mineral and metallic dust , water, fuel, etc.). This circumstance makes it possible to reapply the refined (reclaimed) oil.

Thus, the degree of contamination of lubricating oil with impurities is a direct indicator of the degree of quality of oils for a given condition.

The aging of the oils depends mainly on the conditions of engine exploitation, its design, condition and on the fuel and lubrication used. By virtue of this, it would be wrong to assume that lubricating oil ages equally under different operating conditions and must be replaced after an equal number of hours. The established uniform dates for changing the oil can be accepted only in the order of first approximation, since there was no convenient way to control the condition of the oil for production conditions. In fact, the oil was replaced either by the oil too early (which caused excessive consumption of lubricating oils and increased downtime), or too late (which caused increased wear of engine parts, reduced power and increased fuel consumption). Thus, the correct determination of the degree of suitability of the oil for further work for specific conditions is essential, as it allows saving oil, reducing engine wear and increasing their performance.

However, the determination of the degree of suitability of lubricating oils for their further work according to the degree of their contamination was delayed by the lack of a simple and convenient for field conditions method of quality control.

According to the invention, a method is proposed for determining the quality of lubricating oils according to the degree of their contamination, which consists in diluting a sample of the test oil with a certain amount of gasoline, putting a drop of solution on a filter or so-called paper, and after absorbing a drop of solution, compare the color of the resulting oil spots with the color of standards corresponding to oils with known degrees of contamination.

If a drop of lubricating oil is pipetted onto a sheet of paper, then this drop will tend to spread over the paper, and the paper will begin to be impregnated with oil.

At the same time, impurities suspended in the solution (oil) will spread along with the oil on the paper, impregnate it and, if the impurities are lower than the oil, form a dark spot on the paper. The more particles of particles that appear per unit area of the spot, the darker the spot will be. Therefore, if the quality of the paper (its thickness, processing, porosity) were unchanged, and if identical drops of different solutions formed spots of the same size on this paper, then the impurity content in the oil under test could be determined using the expression

where: Cj is the content of impurities in the test solution, c is the content of impurities in the drop of the reference solution, d and rf are the corresponding thicknesses of the layers deposited on the surface of the paper impurities (sediment density).

The color of the spot would depend on the number of particles settled per unit area of the particle, i.e., on the value of dj. Selecting according to the standard dj (/ 2, we obtain Cj - s, which allows comparing the color of the spots to determine the concentration of impurities in the oil.

For all this, the definition of "impurities" implies not only mechanical impurities (mineral particles, metallic dust, etc.), but also the decomposition products of oil and fuel suspended in solution (sediment).

To carry out the proposed method to use paper, giving a large spreading and small

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impregnability, it is impossible, since irregularities, blotches, bends and tilt in any direction, change the thickness of the layer of spreading droplets and distort the results of observation. For this, the most suitable paper is the one that provides the least spreadability (this ensures the stability of impurity sedimentation, and, consequently, the coloration within the original spot), i.e., the non-glued or low-glued paper is filter or blotting white.

The thicker the paper, the more stable the original spot. Porous but very thin paper soaks through the entire thickness, especially with large drops almost instantly, which increases the spreading of the drop.

It is desirable that the paper pulp fibers are homogeneous, i.e., that the paper is made from the same type of raw material. This will provide insignificant fluctuations in size, and hence the color of the secondary spot. But this requirement is less significant, since, according to the experiments, the critical speed for different grades of porous paper fluctuates slightly, and therefore the width of the ring of the secondary spot varies little.

In practice, the determination of the quality of lubricating oils is carried out as follows.

Immediately after stopping the engine, take a small sample of the test oil (5-10 cm) and add exactly the same amount of gasoline to it. Slurry vigorously shake for 1-2 minutes. (until complete dissolution).

Pipette gain a little of the resulting solution. From a height of 2-3 cm, one drop of oil is pipetted down onto a small piece of white filter or blotting paper. The droplet is quickly absorbed into the paper.

After the droplet has been absorbed, its color (at the original spot) is compared with the reference colors or reference spots and the impurity of the oil is determined according to the most appropriate color for the reference.

The whole operation is carried out in the field and takes 3-5 minutes. Then two identical samples of the used oil are taken (the more the oil worked, the better) and one of the samples in the laboratory determines the contamination with mechanical impurities. One takes the selection of the required standards (as a percentage of contamination) and calculates how many parts of gasoline (by volume) one has to dissolve the oil in order to obtain a reference spot. The calculation is made by the formula:

,

where: n is the number of parts of gasoline (by volume) per one part of the oil, m is the oil contamination in% determined in the laboratory, the e-desired reading (on the contamination in%) of the standard, In the calculated proportions, the second sample oil is dissolved in gasoline and, preparing the paper for the reference (with the corresponding inscriptions), drop a drop of the corresponding solutions with a pipette on this paper.

For example, a laboratory debris in used oil is determined to be 5%. Standards are required that show oil contamination at 1, 2, 3, 4, and 5%. To prepare a standard showing 1% debris, one part of the second sample oil should be dissolved in

  : 9 parts of gasoline; for

the standard showing debris in 2%, one part of the oil of the second sample

dissolved in n parts of gasoline; in the same way, for a reference of 3%, 2.3 parts are obtained.

gasoline, for a reference in 4% -1.5 parts and for a reference in 6% - 1 part.

New standards should be prepared in cases of transition in determining the contamination of oils: a) from light gasoline (for example, aviation) to heavy and vice versa, and b) when switching from one sort of filter or blotting paper to another, differently than the thickness, diameter capillary and density.

Standards and equipment should be issued to the foremen of the tractor brigades or mechanics if the tractor drivers work without joining the brigade. Through careful storage, the benchmark can serve the entire field season - from spring to frost. It is necessary to protect the standards from abrasion and contamination and to protect them from the sun in order to avoid fading. Therefore, standards should be stored in envelopes. In the event of the loss or damage of standards, it is necessary to produce it with a stock, which, however, will not cause any noticeable additional costs of labor and resources.

Subject invention

The method of determining the quality of lubricating oils according to the degree of their contamination, characterized in that the sample of the test oil is diluted with a certain amount of gasoline, put a drop of solution on filter paper or the like and, after soaking up a drop of solution, the color of the formed spot is compared with the color standards corresponding to oils with known degrees of contamination.