Moisture Contamination in Oil
It is almost certain that some amount of water is present in hydraulic and lubrication systems. Water contamination accelerates the aging process resulting in oxidation, hydrolyses, additive depletion, reduced lubricant film strength, corrosion and damage to components.

Because of the destructive potential of water, hydraulic and lubrication fluids are best operated with a water content well below their water saturation point. In practice, water is certainly the biggest enemy of lubrication fluids. Additive decomposition, cavitation and corrosion affect both the system components and also the operating fluid.

Water occurs in three forms in hydraulic and lubrication oils:

• Dissolved water, which is invisible
• Emulsified water, which is visible as water droplets, distributed finely in the oil
• Free water, which forms a visible phase, distinct from the oil.

Aqua Sensor AS 2000
AquaSensor continuously monitors an oil's water saturation level and temperature. The AquaSensor includes a LED display/keypad, two analogue outputs, four easily adjustable switch outputs, and a serial RS485 interface and can be easily calibrated.

Operating Principle of Aqua Sensor
A special capacitance sensor is used in the Aquasensor. Water molecules are moved into and out of the sensor by changes in the saturation level of the oil. The capacity value of the sensor changes with the population of the water molecules in the sensor and is directly related to the saturation level. The change in capacity value is electronically converted and displayed as the saturation level in percent.

A further development of the AquaSensor AS 2000 introduced 3 years ago is the new AS 1000. By reducing the range of functions, miniaturizing it to the size of a pressure sensor and by thus optimizing the costs, the AS 1000 has become very attractive for use in OEM applications, for example in mobile hydraulics and in machine tools. Another newly developed product AquaSensor 8000 is mainly fitted in the return lines of existing systems to measure free water.

Desired saturation level in hydraulic and lubrication systems?
Since the effects of free and emulsified water are more harmful than those of dissolved water, water levels should remain well below the saturation point. However, even water in solution can cause damage and therefore every reasonable effort should be made to keep saturation levels as low as possible. There is no such thing as too little water. As a guideline, we recommend maintaining saturation levels below 45% in all equipment.