Hydraulic oil filter elements are labeled with nominal filtration accuracy on the manufacturer's product catalog or nameplate, not absolute filtration accuracy. Only the β value, determined through testing, can represent the filter element's filtration capacity. Hydraulic oil filter elements should also meet pressure loss requirements to ensure optimal flow rate and filter life. So, how should we correctly select a hydraulic oil filter element?
We suggest considering the following aspects:
1. Filtration Accuracy
First, determine the cleanliness level based on the needs of the hydraulic system, and then select the filter's filtration accuracy based on this cleanliness level. Since nominal filtration accuracy cannot truly reflect the filter element's filtration capacity, the diameter of the largest hard spherical particle that the filter can pass through under specified test conditions is often used as its absolute filtration accuracy to directly reflect the initial filtration capacity of a newly installed filter element.
2. Flow Characteristics
The flow rate and pressure drop of the oil passing through the filter element are important parameters of its flow characteristics. Flow characteristic tests should be conducted according to international standards to plot the flow rate-pressure drop characteristic curve.
3. Filter Element Strength
A burst-impact test should be conducted according to international standards. The pressure difference that drops sharply when the filter element fails should be greater than the specified value.
4. Flow Fatigue Characteristics
A fatigue test should be conducted according to international standards. The filter element must undergo a fatigue test of 100,000 cycles.
5. Hydraulic Oil Compatibility Test
A pressure flow withstand test should be conducted according to international standards to verify the compatibility of the filter media with the hydraulic oil.