Design And Selection Of Oil Filter

Jun 18, 2020

The purpose of various oil filters

a. Suction port oil filter: The main function of this oil filter is to protect the pump, so the filter element does not need to be very thin, and the resistance of the suction port must not be greater than 0.3bar, otherwise it is easy to cause the dissolved gas in the oil to be released. In turn, pitting corrosion occurs in the pump. The average worker would think that this oil filter is sufficient, in fact it is insufficient, because the cleanliness of the oil required by the pump and the high-speed valve are different.

b. High-pressure oil filter: mainly used to protect valves, such as proportional valves and servo valves, so the original should be more delicate. This oil filter is a very important component for valve protection and stabilization, so it should be maintained frequently. Self-lubricating bearings.

c. Oil return filter: There are not many users in general, because it is easy to cause oil return back pressure resistance, and it is more likely to have a booster effect when blocked. However, it can prevent the particles generated by component wear from flowing into the fuel tank and cause pump damage, and can create a system that does not need to change oil.

d. By-Pass Filter

The oil filter in the main line has high resistance if it is high in precision, which is often a problem for the designer, and the bypass oil filter does not affect the operation of the pipeline, so it is often possible to use a very fine filter, but the number of hours and Probability is one of fatal injuries. If you use the By-Pass Filter to run the machine before the trial operation, very good results will be achieved

e. Fuel filler screen: prevent impurities from entering the fuel tank when adding or replenishing oil. Generally, this filter screen is easy to be overlooked, but it should be noted that this is a pollution inlet, so be careful.

f. Magnetic filter: This is a new generation of technological products, which can absorb iron filings and even impurities in oil, and there is no mesh problem with the oil filter, so it can filter oil.

Selection of oil filter

The performance of general oil filter is based on β value (Belta Ratio)

The oil filter performance for particles of oil size Xμ and pollutants is

Generally speaking, the oil filter performance β value must be greater than 75, which means that the oil filter can effectively filter out particulate pollutants of this level.

For the oil suction filter that needs to protect the pump, the oil should be kept below NAS level 9, so a filter with β12> 75 must be used.

The high-pressure oil filter used to protect the server and the proportional valve should use a filter with β3> 75. But it is worth noting that the β value is only a proportional problem. If the oil is not clean at the beginning, it must be filtered several times. The oil products that meet the requirements can be obtained, so it is very important to clean the parts of the pipeline before assembly.