Hazards Of Excessive Water Content in Hydraulic Oil And Control Measures

Writer： Kaiqian Oil Purifier Release time：2025-11-03 16:20 Clicks：

  In hydraulic equipment lubrication management, controlling contamination in hydraulic oil is essential for minimizing wear, enhancing reliability, and improving availability. Among various contaminants, such as air and solid particles, water is the most critical. Excessive water can cause damage to hydraulic systems, making accurate detection and effective control through scientific methods imperative.

I. Core Hazards of Water Contamination in Hydraulic Oil and Systems

Water ingress adversely affects hydraulic systems on three levels: physical properties, chemical stability, and operational performance. Specific hazards include:

Impairment of Lubrication Performance: Water can alter the viscosity of hydraulic oil, causing it to become either too thick or too thin. This thins or breaks down the oil film, resulting in inadequate lubrication of moving parts, increased wear, and potential adhesion. It also directly reduces the oil's lubricity, leading to unstable equipment operation.

Reduced Pressure Stability: Water increases the compressibility of hydraulic oil, causing fluctuations in system output pressure. This compromises operational accuracy and the ability to meet precise working requirements.

Accelerated Oil Degradation: Water dissolves additives in hydraulic oil, degrading its antioxidant and anti-corrosion properties. At high temperatures, water readily reacts with oil to produce acidic compounds and sludge, shortening oil service life and potentially promoting bacterial growth. This accelerates oil deterioration and increases replacement costs.

Damage to Metal Components: Acidic byproducts from oxidation reactions corrode metal parts, while water accelerates surface fatigue and rust formation. At low temperatures, water may freeze into ice, blocking moving parts and causing system failure.

Increased Maintenance Costs: Impurities and oxidation products from water can clog filters, reducing filtration accuracy. This not only necessitates frequent filter changes and raises costs, but also allows more contaminants to enter the system due to compromised filtration, indirectly reducing the service life of components.

Furthermore, water combined with metallic wear debris (e.g., copper or iron particles) creates a "catalytic effect." Metal particles accelerate the oxidative breakdown between water and oil, promoting the formation of additional corrosive products and initiating a vicious cycle of "contamination → damage → further contamination."

II. Emulsion: A Special Form of Water Contamination

  When free water-such as intruded water or dissolved water, precipitates at low temperatures vigorously agitated by the oil pump or sheared by valve components, it disperses into fine droplets suspended in the oil. These droplets cannot settle and eventually form an emulsion, giving the oil a cloudy, milky appearance. Emulsion is more harmful than free water: it completely disrupts the oil film structure, leading to lubrication failure, and accelerates additive depletion and metal corrosion. If not addressed promptly, it can result in serious failures such as pump wear and valve sticking.

III. Scientific Methods for Testing Water Content in Hydraulic Oil

Two primary methods are used to determine whether water content exceeds acceptable limits: rapid on-site qualitative testing and precise laboratory quantitative analysis. The choice depends on specific needs:

On-Site Hot Plate Test (Qualitative Analysis): This is the simplest field method. Place 1–2 drops of the hydraulic oil onto a clean, flat, thin metal plate. Heat the plate to approximately 120°C using a lighter or alcohol lamp. If bubbling or a slight crackling sound is observed, the oil contains excessive water.

Laboratory Karl Fischer Method (Quantitative Analysis): For precise measurement of water content, this method utilizes a chemical reaction to determine the amount of water in the oil accurately. It provides highly accurate data to support subsequent moisture control decisions.

IV. Controlling and Removing Excess Water from Hydraulic Oil

Kaiqian's ZL Series vacuum oil filter is an effective solution to high water content in hydraulic oil. Its core advantages and working principles include:

Core Function: It efficiently removes liquid water, free water, and dissolved water, as well as gases, solid impurities, and minor impurities. This restores key properties of the hydraulic oil, such as viscosity and flash point, ensuring proper operation of hydraulic, power, and lubrication systems.

Technical Principle: The system utilizes "micro-flash evaporation technology" and high precision separation. It effectively separates all forms of water and completely breaks down emulsion structures, preventing re-emulsification. As a result, previously cloudy emulsified oil becomes clear and transparent again, meeting hydraulic equipment standards.