What are the technical characteristics of oil filters?

Technical characteristics
● Filter paper: The oil filter has higher requirements on the filter paper than the air filter, mainly because the temperature of the oil varies from 0 to 300 degrees. Under the sudden temperature change, the concentration of the oil also changes accordingly. Will affect the filtration flow of engine oil. The filter paper of a high-quality oil filter should be able to filter impurities under drastic temperature changes while ensuring sufficient flow.
●Rubber seal ring: The filter seal ring of high-quality motor oil is made of special rubber to ensure 100% oil-free.
●Backflow suppression valve: only available in high-quality oil filters. When the engine is turned off, it can prevent the oil filter from drying out; when the engine is re-ignited, it immediately generates pressure to supply oil to lubricate the engine. (Also called check valve)
●Overflow valve: only available in high-quality oil filters. When the external temperature drops to a certain value or when the oil filter exceeds the normal service life, the overflow valve will open under special pressure to allow unfiltered oil to flow directly into the engine. Despite this, the impurities in the oil will enter the engine together, but this damage is much smaller than the damage caused by the absence of oil in the engine. Therefore, the relief valve is the key to protect the engine in an emergency. (Also called bypass valve)