What is the principle of mechanical impurity determination? What should be noted in the determination of mechanical impurities? 

Answer:The mechanical impurity determination method is a quantitative analysis method. The oil is first diluted with solvent and then filtered through a filter paper or other filter to separate out the solid particles contained in the oil.

The oil is then filtered through a filter paper or other filter to separate out the suspended solid particles and then rinsed out with solvent. The oil is dried and weighed and the results are expressed as a percentage.

The following should be noted for the determination of mechanical impurities.

(1) The sample must be weighed and shaken well first.

(2) All solvents should be filtered before use.

(3) It is advisable to use filter paper of the same density and thickness as well as the same type and quantity of solvent.

(4) The empty filter paper should not be dried in the same oven as the precipitated filter paper to avoid adsorption of solvent and oil vapours on the empty filter paper, which may affect the constant weight.

(5) After the specified cooling time, the product should be weighed immediately. In order to avoid that the constant weight is affected by the hygroscopic effect of the filter paper after a long period of time.

(6) The filtration operation should be carried out in strict compliance with the relevant regulations for weight analysis.

(7) The solvent used should be selected according to the specific circumstances of the test and the relevant provisions of the technical standards, and should not be used indiscriminately.

(8) Determination of double curve gear oil, saturated cylinder oil and other lubricating oil mechanical impurities, to pay attention to the residue on the filter paper with or without sand and its friction

Sexual material, because these products are not allowed to have sand and other frictional material.