Water contamination is the number one cause of hydraulic system failure which can be an extremely costly experience. While it’s next to impossible to prevent water from entering the system at one point or another, using the right hydraulic fluid along with some best practice preventative maintenance measures should prevent the water from causing mechanical issues.
Why Water Contamination Is An Issue in Hydraulic Systems
If water is left to sit in a hydraulic system it will cause chemical reactions that corrode the equipment as well as reducing the effectiveness of lubricants, leading to a much shorter lifespan.
It is next to impossible to completely prevent water from entering the hydraulic system due to the nature of its use. Externally water can enter through leaky seals, rain or even regular wash downs. Internally, simple changes in temperature from shut down to working mode can cause condensation that enters the machine. Because of this, it’s best to focus on removing water from the system rather than completely preventing it from getting in. This is where your choice of hydraulic fluid can make a big difference.
How Hydraulic Fluid Can Impact Water Contamination
To effectively remove water from your hydraulic system, the type of hydraulic fluid used can have a big impact.
Ester-based hydraulic fluids are designed to absorb water contamination. The theory here is that by the lubricant absorbing the water, there is no need to check or remove water from the system. While ester-based oils do absorb water, temperature fluctuations often mean not all water is emulsified, leaving free water to damage the system. As an example, a typical ester-based oil will dissolve water at an operating temperature of 37°C, however when the machine cools down to an ambient temperature of 21°C when not in use free water will appear as the oil does not emulsify at ambient temperatures.
Most equipment manufacturers (OEMs) recommend traditional demulsifying lubricants which allow water to be removed through normal separating methods such as draining, centrifuges, coalescers or absorbent filters. The performance of these hydraulic fluids depends on the quality of the base oil used, the additives, temperature and pressure.
HYDREX™ and ENVIRON™ Hydraulic Fluids are made from 99.9% crystal clear base oils, allowing them to hold little water before becoming saturated. They are developed with additives to perform year-round in a wide range of temperatures, resisting thermal and oxidative breakdown, and providing extended drain intervals and protection against equipment wear. The ENVIRON™ range is specially formulated for environmentally sensitive areas.
Is Water Contamination An Issue With Your Hydraulic System?
It’s unlikely your hydraulic system will simply fail overnight, rather there will be signs of the looming danger long before it occurs. If you notice any of the following, it’s time to make some changes before it’s too late:
‘Cloudy’ looking oil/fluid – in changing out your oil, or testing, if it looks cloudy there is too much water entering and staying in the system.
Surface corrosion – check for any rusting or corrosion on the surface.
Fluid life is reduced when oxygen molecules in the water begin chemical reactions to oxidize the fluid.
You may notice your hydraulic oil have reduced viscosity, lubricity, compressibility, and load-carrying capability.
Water present in the bearing load can create extremely heated steam that can cause a mini explosion within the oil and damage the fluid and crack bearing surfaces.
Hydrolysis can be an issue with ester-based fluids where water and heat acting together can cause decomposition. This causes acids to form which wear and corrode system components.
If operating in low temperatures, crystallisation can impede the operation of the system.
If operating at higher temperatures the system may be forced to work harder and will therefore respond more slowly.
Vapour pockets may form within the fluid, reducing effectiveness and fluid life (cavitation).
Too much foaming can result in a slow-responding hydraulic system, as well as cavitation.
The performance of your hydraulic fluid may be reduced due to premature additive depletion or precipitation.
Sludge formation — water can bond with other system contaminants, creating a sludge that could overwhelm strainers and other filtration measures, restricting oil flow in the system.
5 Best Practices To Prevent Hydraulic System Failures
While using a top performing hydraulic fluid will make the world of difference in preventing water contamination, there’s a few best practices to follow to ensure your hydraulic fluid keeps performing at its best. Here they are:
1. Oil Testing – take any guesswork out of the equation and have your oil tested regularly. An analysis of your oil will not only pick up the water levels present in your fluids but can also detect any loss in performance such as viscosity or lubricity. It’s like a blood test for your machine where the results give you the information needed to take any action needed before it gets too serious.
2. Check your hydraulic fluid levels regularly.
3. Implement a fluid change-out schedule – like anything, lubricants degrade over time which is why machines always seem to perform better after a change-out. Your oil analysis can help determine the optimum intervals for scheduling in change-outs.
4. Attend to any leaks immediately regardless of how small they may seem. Remember small leaks can quickly turn into big problems if left unattended.
5. Follow your equipment manufacturer recommendations and don’t cut corners on maintenance! The cost of regular maintenance is much smaller than the ramifications of a system failure.