How to Remove Metal Powder from Hydraulic Oil Efficiently?

How to Remove Metal Particles from Hydraulic Oil (Concise Guide)

Removing metal particles from hydraulic oil requires a systematic approach combining diagnosis, filtration, and prevention.

Step 1: Identify the Source

Inspect magnetic drain plugs and filters for metal residue.

Color analysis helps pinpoint wear:

Copper color → Bushings, thrust washers

Steel/Iron color → Bearings, gears, shafts

In operating equipment, metal particles usually indicate abnormal internal wear.

Use oil analysis (ISO 4406 / NAS 1638) to determine the degree of contamination and particle size.

Step 2: ｓｅｌｅｃｔ the Appropriate Filtration Method

1. Magnetic Filtration (Primary Method)

Effectively removes iron and steel particles

Uses magnetic filter elements, rods, or drain plugs

Ineffective for non-ferrous metals

2. High-Precision Mechanical Filtration (Essential Method)

Recommended precision: 3–5 μm, β₃ ≥ 200

Uses return/pressure oil purifiers and offline filtration carts

Requires continuous circulation; single filtration is insufficient for complete impurity removal

3. Electrostatic Filtration (Optional)

Removes sub-micron metal particles

Used for deep oil purification

4. Centrifugal Separation (Optional)

Suitable for large, high-density metal particle filtration

Often used for pre-treatment

Step 3: Cleaning and Prevention

Severely contaminated systems require oil draining and flushing

Thoroughly clean the oil tank and piping

ｒｅｐｌａｃｅ all filter elements after purification

Repair worn components to prevent re-contamination

Perform regular oil analysis and purification filtration

Key Points:

Filtration alone is not enough – first eliminate the source of wear, then use magnetic filtration and high-precision filtration to restore oil cleanliness.