Weigh a certain amount of sample, dissolve it in the solvent used, and filter it with a constant weight filter. The impurities left on the filter are mechanical impurities (petroleum products and additives mechanical impurities tester). The automobile engine is composed of many precision components. The mechanical impurities contained in the fuel and lubricating oil will not only affect the normal supply of fuel, but also cause the wear of components. Therefore, the indicators of petroleum products must be limited. When determining mechanical impurities, we should pay attention to the following aspects:
1. The solvent and reagent shall be filtered before use to prevent high results.
2. The new microporous glass filter needs to be treated with chromic acid lotion before and after use, and then washed with distilled water, and placed in the drying oven for drying before use. After the test, it should be soaked in chromic acid lotion for 4~5h, then washed with distilled water, and then put into the dryer for standby after drying.
3. In case of any dispute between the results measured by microporous glass filter and filter paper in the test, the results measured by filter paper shall prevail.
4. When using filter paper, a blank test of solvent must be carried out.