What is What is Varnish ?Varnish - FOCUSLAB Flipbook PDF

Varnish is a soft contaminant composed of lubricant degradation by-products that are less than 1 micron in size and is n

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What is Varnish ? ƒ Varnish is a soft contaminant composed of lubricant degradation by-products that are less than 1 micron in size and is not measured by traditional particle count. ƒ Varnish deposit is a thin-orange, brown or black insoluble film deposit occurring on internal of lubricant systems . ƒ Varnish is a high molecular weight substance that is unstable in oil. ƒ Varnish deposit is unable to remove by mechanical filtration

Varnish formation on gas compressor -gear

Varnish formation on Inlet Guide Vane

Varnish formation on pencil filter Varnish formation on spool valve

Varnish formation on a turbine bearing

What is Sludge ? Sludge

„ Sludge is varnish which have higher water content „ Sludge looks like a soft mud-like deposit that settles out of the oil „ Sludge is also a soft contaminant . „ Sludge contaminant , if prolonged elevated temperatures will evaporate the moisture from the sludge contaminant.

Sludge

Sludge Combination of varnish & sludge

What are the negative impacts ? Varnish build-up has long been a problem , particularly in turbine and hydraulic . System failures due to varnish problem can be :

Spool valve sticking due to varnish formation

ƒ Sticking or seized occurs in moving mechanical parts such as servo control valve. ƒ Plugged or restricted small oil flow orifices ƒ Loss of heat occurs in heat exchangers due to varnish’s insulation effect , cause to increase oil temperature ƒ Attract dirt and larger contaminants , increasing wears and component failure.

Varnish layer Silt

Varnish formation on spool valve

ƒ Encourage premature bearing failure. ƒ Catalytic deterioration of turbine oils and hydraulic oils Varnish plated on heat exchangers

What is VsPI™ ?

ƒ VsPI ™ stands for Varnish & Sludge Potential Index™ ƒ VsPI ™ is a test method that have been developed by Focus Laboratories Ltd ƒ VsPI ™ will predict varnish & sludge contamination condition and status in lubricant system . Also , VsPI ™ will monitor varnish & sludge build up rate in lubricant systems ƒ Result of “ VsPI

™ ” will present in rating unit.

ƒ Application : gas & steam turbines , hydraulic systems , turbo compressors and clean lubricant systems .

Importance of Varnish & Sludge Detection and Monitoring Catching Varnish & Sludge Before It Costs You Detect varnish & sludge levels in the lube oil system Monitor the varnish & sludge build-up rate in the lube oil system ¾ High build-up rate or Low build-up rate ¾ If High build -up rate , will be critical and/or have any adverse impacts

Correction the problem in the early stage .

Varnish & sludge Problem Servo Valve Trip /fault due to valve sticking

Servo Valve Trip /fault due to valve sticking

VsPI

Sticky of Servo Valve and Filter plug Sticky of Inlet Guide Valve Turbine A , High build-up rate of varnish

Turbine B , Low build-up rate of varnish Time (hours)

Will you wait until servo valve trip/fault before you identify and dealing with varnish & sludge in gas turbine ?

Oil Analysis Report

VsPI Result in the report

Varnish & Sludge Potential Index Value (VsPI )