Eaton WSPS 05 Instruction Manual

Contents

42. Operation and installation2.1. General informationsWater in hydraulic- and lubricating oil is a fluid contamination, which has to be limitedurgently due to its negative effects on the characteristics of fluids. Among other effects, itdoes accelerate oil aging, it causes the failure of polarizing additives, it increases the acidnumber and it worsens filterability. Effects for a hydraulic or lubricating system are verymanifold and cause significantly increased wear, drastically increased risk of failure ofcomponents as well as malfunctions.Important for these effects of water is whether water present in the fluid is free oremulsified, not the total amount of water. Only free water does have the dangerouschemical or biological reactivity. Therefore the detection of the presence of free oremulsified water in a hydraulic or lubricating system is of great importance.2.2. Measuring principleThe WSPS 05 does utilize a capacitive sensor for measurements.It uses polymeric foil as dielectric for interelectrode capacitance.This foil is capable of absorbing water molecules due to its microporous structure.This absorption causes a change in capacity of this element, which is converted into theoutput signal between 4 and 20 mA.Measurements are the water saturation of the fluid in percent, which is direct proportionalto the output signal of the sensor. (see also the characteristic of the sensor in chapter 5.4)In addition to that a temperature sensor is integrated to determine the exact temperature ofthe fluid while measuring.There is a difference to the measurement of the absolute water content with the Karl-Fischer-method. The Karl- Fischer-method determines the total amount of free andemulsified water in mg – water / kg – oil.The WSPS 05 gives the saturation level of the fluid with water in percent.The indication 100 % means that the fluid is totally saturated.Saturation values depend on the temperature!A relation to the measured saturation values and the stated ppm (mg / kg) value accordingto Karl Fisher’s method is ascertained by the 100 % saturation curve (100% of saturation =f(T)) for the measured fluid and the fluid temperature measured at the same time with thesaturation.