Hydraulic systems play a crucial role in industrial operations, supporting many mechanical processes. However, the efficiency and reliability of these systems can be severely compromised by the formation of varnish, a byproduct of oil oxidation and thermal degradation. Varnish buildup within hydraulic systems not only impairs performance but also accelerates wear and increases maintenance costs. It’s important to have a comprehensive understanding of varnish formation, its symptoms, and the critical reasons maintenance teams must address this issue. Furthermore, an effective solution for managing and preventing varnish accumulation in hydraulic systems must be considered to mitigate its impact.
Understanding Varnish in Hydraulic Systems
In hydraulic systems, oil is continuously exposed to high temperatures, which accelerates the oxidation process. Contaminants such as dirt, water, and metal particles further catalyze this degradation, resulting in the formation of varnish, a sticky, lacquer-like substance. This varnish can adhere to surfaces within the hydraulic system, causing significant operational issues.
Recognizing Symptoms of Varnish
One of the first signs of varnish buildup is a noticeable decline in system performance. Operators may observe slower system response times and increased power consumption. This is because varnish impedes the smooth flow of hydraulic fluid, making the system work harder to achieve the same output.
Physical symptoms of varnish include sticky residues on hydraulic components and discolored, darkened oil. These residues can coat the surfaces of valves, pumps, and other critical components, leading to operational inefficiencies and potential failures.
Additionally, varnish buildup often leads to more frequent maintenance issues. Operators might find themselves changing filters more often due to clogging, dealing with valve sticking problems, and facing system overheating. These maintenance challenges can disrupt operations and lead to costly downtime.
What Happens When You Ignore Varnish
Ignoring varnish in hydraulic systems can have severe consequences. Here's why operators should pay close attention to this issue:
Reduced Efficiency and Performance: Varnish impedes fluid flow and reduces the efficiency of the hydraulic system, leading to sluggish performance and higher energy consumption.
Accelerated Wear and Tear: The presence of varnish increases friction and wear on components, shortening their lifespan and leading to more frequent replacements.
Higher Operational Repair Costs: The cumulative effect of reduced efficiency, accelerated wear, and frequent maintenance issues results in higher operational and repair costs. Addressing varnish proactively can save significant expenses in the long run.
Solutions for Managing and Preventing Varnish
Managing and preventing varnish in hydraulic systems requires a proactive and multi-faceted approach. By implementing regular monitoring and maintenance practices, operators can significantly reduce the risk of varnish formation.
Regular Monitoring
Oil analysis is a crucial tool for detecting and preventing varnish in hydraulic systems. It involves several techniques that help identify the early signs of varnish formation. For instance, measuring oil properties such as the Total Acid Number (TAN) and oxidation levels can indicate oil degradation and the presence of varnish precursors. Identifying contaminants through particle count analysis and assessing water content further helps in detecting conditions that contribute to varnish formation. Spectroscopic analysis, including Fourier Transform Infrared (FTIR) spectroscopy and ultracentrifuge analysis, detects specific chemical compounds and sub-micron particles associated with varnish. Additionally, visual inspection of the oil’s color and appearance can provide early warnings of varnish buildup.
Preventing varnish involves using oil analysis for trend analysis, allowing for the tracking of changes in oil properties over time. This enables early detection of trends suggesting varnish formation and facilitates timely intervention, such as scheduling maintenance actions before significant issues arise. Optimizing oil life through additive depletion monitoring ensures that antioxidant additives are replenished before they are fully depleted, thereby extending the oil’s life and reducing varnish risk.
Filtration and Oil Cleanliness
Effective filtration systems are essential in maintaining oil cleanliness. High-efficiency filters can remove particles and contaminants from the oil, thereby reducing the likelihood of varnish formation. Regularly updating and maintaining filtration systems ensures that they continue to function effectively. Advanced filtration technologies, such as depth filters and electrostatic oil cleaners, can capture even the smallest particles that standard filters might miss.
Implementing programs like Chevron’s ISOCLEAN® can ensure that the oil used in hydraulic systems meets stringent cleanliness standards. The ISOCLEAN program involves pre-filtering oil to meet OEM cleanliness standards, removing contaminants before it is introduced into the system. This ensures that the oil starts off clean, reducing the risk of varnish from the outset.
The type of hydraulic fluid used in a system can also significantly impact the likelihood of varnish formation. In particular, ashless hydraulic fluids tend to have less varnish-forming potential compared to zinc-containing hydraulic fluids. This is because Ashless hydraulic fluids are formulated with additives that do not contain metallic elements. Since these fluids do not contain metal-based additives, they do not leave ash residues when they degrade, and the absence of ash-forming elements reduces the potential for varnish formation. Zinc-containing fluids, on the other hand, produce zinc oxide and other metallic residues. These residues contribute to the formation of varnish, as they can accumulate on hydraulic components and promote oxidation and thermal degradation.
Chemical Cleaners
Chemical cleaners are effective in removing existing varnish deposits. These cleaners contain solvents that can dissolve varnish deposits into smaller, more manageable particles. These solvents disrupt the molecular bonds holding the varnish together, allowing it to be flushed out of the system. This is where solutions like Chevron’s VARTECH® system cleaner come into play.
Chevron's VARTECH Industrial System Cleaner
Chevron’s VARTECH Industrial System Cleaner (ISC) is a specialized solution designed to remove varnish from hydraulic systems efficiently. Unlike some cleaners that may clog filters or require significant downtime, VARTECH ISC cleans varnish without these drawbacks.
Systems treated with VARTECH showed marked improvements in performance and reduced operational issues post-cleaning. Comparative studies using coupons have demonstrated the cleaner’s ability to remove stubborn varnish deposits effectively.
Using VARTECH ISC is straightforward and does not require shutting down the system. Operators can follow the provided guidelines on concentration and usage frequency to integrate VARTECH into their regular maintenance routines. This ease of use ensures that systems remain operational while being cleaned, minimizing downtime and disruptions.
Bottom Line
Varnish in hydraulic systems is a hidden threat that can significantly impact performance, efficiency, and operational costs. Recognizing the symptoms and understanding the importance of addressing varnish is crucial for maintaining the health of hydraulic systems. Chevron’s VARTECH system cleaner offers a powerful solution to this problem, enabling operators to keep their systems clean and efficient.
To learn see VARTECH in action and learn more about the dangers of varnish in hydraulic systems, check out our free webinar “Varnish Vanquished: Defeating Your Hydraulic System’s Biggest Enemy”.
