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Time：2025-11-19 16:36:58 Reading volume：
Water intrusion in hydraulic oil is one of the most common causes of system failures. Excess moisture can trigger oil oxidation, corrosion, reduced lubrication, and component damage, which ultimately shortens equipment life. To maintain system reliability, it’s essential to identify the type of moisture present and choose the correct hydraulic oil water filtration method.
Before selecting a dehydration method, determine how water exists in the oil. Hydraulic oil typically contains moisture in three forms:
Free Water
Separates and settles at the bottom of the tank
Visible stratification
Easy to remove through drainage or sedimentation
Oil appears milky, cloudy, or white
Formed when water is mixed and dispersed by fluid agitation
More difficult to remove and requires specialized filtration
Not visible to the naked eye
Exists at a molecular level
Accelerates oxidation and shortens oil life
Correct identification ensures you choose the most effective treatment.
Utilizes settling tanks to allow free water to separate naturally
Water is drained via the bottom drain valve
Best for: routine maintenance and simple water contamination events
Limitations: ineffective for emulsified or dissolved water
Uses a coalescing filter element to combine fine water droplets into larger ones for easy removal
Moisture reduction: typically < 200 ppm
Advantages:
Effective on emulsified water
Low energy consumption
Cost-effective for most hydraulic systems
Removes water by heating, atomizing, and vacuum evaporation
Moisture reduction: often < 100 ppm
Advantages:
Works for all water types (free, emulsified, dissolved)
Most thorough dehydration method
Ideal for high-precision or moisture-sensitive hydraulic equipment
Choose the right method based on contamination level and system requirements:
Slight emulsification:
→ Use a coalescing oil filter
Severe emulsification or precision hydraulic systems:
→ Use a vacuum oil purifier for deep dehydration
Routine maintenance:
→ Drain free water + occasional offline filtration
Matching the method to the moisture type maximizes efficiency and protects equipment.
Test water content before filtration to confirm the level of contamination.
Use offline (kidney-loop) filtration whenever possible to avoid downtime.
ｒｅｐｌａｃｅ severely degraded oil, as filtration cannot reverse chemical breakdown.
Check explosion-proof and safety requirements when using filtration equipment in hazardous environments.
Practical Tip
For general industrial use, a mobile coalescing oil filter is sufficient for routine dehydration.
For precision hydraulic machinery or critical equipment, schedule periodic deep treatment with a vacuum oil purifier to maintain optimal performance and extend oil life.
