Varnish Mitigation

We offer 2 different technologies:

We are available for Long Term Varnish Mitigation Services, Varnish Testing Services and Emergency Varnish Mitigation Services .

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Varnish or lacquer is a high molecular weight substance that is insoluble in oil. If left untreated, varnish insoluble's will agglomerate into larger particles and deposit on machinery surfaces, especially around critical small clearance areas and orifices. This film will build over time and cause numerous problems including mechanical wear, system sticking, filter plugging, poor heat transfer, catalytic deterioration of the lubricant, and eventual mechanical failure. Varnish is a large problem in today’s stressed Industrial Environment. GIS is a leader in removing varnish in turbine, hydraulic and industrial circulating systems utilizing both service and equipment offerings and a unique process to help remove varnish and maintain system cleanliness

What is Varnish?

A thin, hard, lustrous, oil-insoluble deposit, composed primarily of organic residue, & most readily definable by color intensity. It is not easily removed by wiping with a clean, dry, soft, lint-free wiping material and is resistant to saturated [light hydrocarbon] solvents. Its color may vary, but it usually appears in gray, brown or amber hues. ASTMD.02C.01 definition

What causes Varnish?

Oxidation is the root cause of the problem. It creates free radicals resulting in acids, alcohols, esters and lactones. Anti-oxidant (AO) additives are designed to neutralize the products of oxidation. As oxidation occurs the phenol and amine additives are depleted. The products of oxidation become the building blocks of varnish.

Polymerization occurs as the by-products of oxidation and additive reactions combine to create longer chain molecules with higher molecular weight. These molecules have lower solubility and are polarized. The rate of molecular polymerization is a function of temperature (as a catalyst) and the concentration of oxidation by-products (free radicals).

Solubility describes fluid's capacity to hold the varnish producing molecules in solution (dissolved). Solubility is directly affected by temperature. As more oxidation by-products are generated the fluid approaches its solubility saturation point, beyond which no additional polymerized molecules can be held in solution and can precipitate out.

Precipitation occurs once the solubility threshold (saturation point) has been crossed or if there is a drop in temperature which reduces the solubility of the fluid. As additional oxidation by-products (free radicals) are generated they become insoluble and precipitate out and are free to form varnish deposits.

Agglomeration begins as insoluble sub-micron soft particles (0.08 micron) that have precipitated out of solution bond to form larger particles (1.0 micron). These agglomerated soft particles remain insoluble, remain polarized, and maintain a higher molecular weight than the fluid itself.

Varnish Forms as the polarized oxidation products come out of solution, agglomerate and collect on metal surfaces. The surfaces where varnish typically forms include cool zones, low flow and low clearance areas. Why? This is where solubility diminishes, precipitation starts and agglomeration goes on undisturbed.

When gas turbines fall casualty to unit trip or fail-to-start conditions, lube oil varnish is the usual suspect! What is your Varnish Potential Rating (VPR)?  Test your oil today with a QSA!

Varnish Solubilty




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