In the process of purchasing an oil filter, high demand users are involved in selecting the matching of filtration accuracy, which directly affects the reliability of equipment lubrication, maintenance costs, and oil life. Improper selection may lead to increased equipment wear or frequent replacement of filter cartridges, resulting in waste.

　　1、 Understand the key parameters of filtering accuracy

The filtration accuracy is usually expressed in micrometers (μ m), but different standards need to be distinguished:

　　Nominal accuracyThe traditional labeling method represents the approximate pore size range of the filter medium, but there is no unified testing standard, resulting in low reliability.

　　Absolute JD accuracy (β value)A rigorous labeling method, where β ₓ=200 indicates that 200 particles larger than x microns enter the upstream and 1 enters the downstream, resulting in a filtration efficiency of 99.5%. The commonly used values in the industrial field are beta ∝, beta ₅, and beta ₁.

　　2、 Core selection criteria: equipment sensitivity and oil state

　　1. Equipment criticality and pollution tolerance

　　High precision hydraulic system (servo/proportional valve)Requirement: β ∝ ≥ 200 (3 μ m filtration efficiency ≥ 99.5%). It is recommended to filter 1-3 μ m for working purposes and 10 μ m for protective filtration

　　Turbine and compressor bearingsβ ₅ ≥ 200 (5 μ m), usually with an accuracy of 5-10 μ m

　　Ordinary gearbox, reciprocating machinery: β ₁₀ ≥ 200 (10 μ m), optional 10-15 μ m

　　Overloading low-speed equipmentHigh tolerance, 15-25 μ m may be sufficient

　　2. Oil type and initial contamination level

　　New oil replenishment filtrationThe new oil itself may contain 20-30 μ m particles, it is recommended to filter at least 10 μ m

　　Oil maintenanceSelect based on the measured pollution level:

NAS level 7 and below: optional 10-15 μ m

NAS level 8-10: Recommended 5-10 μ m

NAS level 10 or above: It is necessary to first use 20-30 μ m pre filtering, and then gradually improve the accuracy

　　3. Consideration of system operating parameters

　　Influence of viscosityHigh viscosity oil (such as ISO VG460) has high filtration resistance and requires a 1-level reduction in accuracy

　　Traffic matchingHigh flow systems can choose slightly lower precision (such as 15 μ m instead of 10 μ m) to ensure flow capacity

　　Pressure limitThe pressure difference of the filter element should be lower than the opening pressure of the bypass valve (usually 0.2-0.35MPa)

　　4.Supporting measures and verification

　　Necessary measures:Install differential pressure indicator or sensor to monitor the status of the filter element

Upstream configuration of 100-150 μ m stainless steel filter screen to protect the oil filter pump

Regularly take oil samples for testing to verify the filtration effect

　　5.Economic balance:

The price of high-precision filter cartridges (β ∝ ≥ 200) may be 2-3 times higher than that of ordinary filter cartridges (β ₁₀ ≥ 200)

But the oil change cycle can be extended by 50-200%, and the overall cost is often reduced by more than 30%

Suggest calculating the total cost of ownership (filter cost+oil cost+downtime loss)

　　6.Correction of common misconceptions

　　The misconception of 'higher accuracy is better'Excessive precision (such as 1 μ m used for ordinary gearboxes) can result in extremely short filter life, frequent replacement increases costs, and secondary pollution risks

　　Misconception of 'One time filtering in place'Severely polluted oil should be improved in stages to enhance accuracy and avoid instantaneous clogging of the filter element

　　Neglecting the misconception of beta valueBy only looking at the "3 μ m" label without considering the beta value, the actual efficiency may only be 70% (beta=3.3) instead of 99.5% (beta=200)

　　Conclusion

Choosing the filtration accuracy of an oil filter is a decision that requires comprehensive consideration of equipment requirements, oil state, and operating parameters. Suggest establishing a preventive maintenance system based on oil analysis and dynamically adjusting filtration strategies. Initial investment in a filtration system with appropriate precision can typically recoup costs within 12-18 months by reducing wear, extending oil life, and lowering failure rates.

Through the framework provided in this article, you can avoid common issues of "over filtering" or "under filtering" and find a balance between device protection and economy. Regular monitoring and data-driven adjustments are key to maintaining the long-term effectiveness of the filtering system.

Note: The parameters in this article are for general reference only. Please follow the manufacturer's special requirements for key equipment. Suggest consulting with suppliers for application validation.