Recently, an old Korean customer inquired about replacing the MUT filter element, the filter element model is 5501800016, 2300 pieces. The material of this filter element is filter paper. We call this filter element an oil filter element. Oil filters have higher requirements for filter paper than air filters, mainly because the temperature of the oil varies from 0 to 300 degrees. Under severe temperature changes, the concentration of the oil will also change accordingly, which will affect The filter flow rate of the oil. The filter paper of high-quality oil filter can filter impurities and ensure sufficient flow under severe temperature changes. 

There are 3 characteristics of the oil filter element：

1. Rubber sealing ring: The filter sealing ring of high-quality engine oil is made of special rubber to ensure 100% oil leakage.

2. 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.

3. 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, allowing unfiltered oil to flow directly into the engine. Even so, the impurities in the oil will enter the engine, but it is much smaller than the loss caused by the absence of oil in the engine. Therefore, the overflow valve is the key to protect the engine in an emergency.

The process of this kind of filter element is simple, but the amount of filter element is very large, and the customers are only purchasing and using it by thousands. We give our customers the greatest preferential price, and after negotiation between our two parties, we compromised. In the end, we reached a cooperation with the customer. The customer placed an order from us as an annual purchase product, and no less than 10,000 filter elements a year, and the payment terms were also negotiated with the customer. We first send a sample to the customer for testing. The sample has passed the test and the customer has placed an order of 3000 as the first batch order.