Hydraulic Oil Life
Hydraulic oil life is important to maintain healthy systems and components. There are methods to help look after your hydraulic oil…
Modern hydraulic systems are typically a lot smaller and more compact than they used to be, meaning that less hydraulic oil is used during operation. Pumps can also produce a lot more output, subsequently producing higher pressures. Less oil within the system also means higher fluid temperatures – which in turn, increases oxidation and thermal stress on the additives on the oil. However, engineers still want the most cost-effective oils that last as long as possible and still operates faultlessly.
The longevity of hydraulic oil depends on a few influences: the quality of the oil, working conditions and possibly even contamination. However, a high quality hydraulic oil should be able to last at least six months if the environments it is in aren’t harsh. With maintenance and up-keep, the hydraulic oil life should be able to last much longer.
Hydraulic oil life can be greatly impacted by the temperature of the oil during operation. The most common temperature in most industrial applications is around 60°C, however it may fluctuate and even rise to 85°C, which is normal. If the oil temperature remains at 85°C for a long period of time, there is a risk of restricting the life of your oil, as the oxidising process is enhanced. For every 10°C that the temperature increases, the more the oxidation increases and thus, significantly reducing the hydraulic oi life.
Oxidation is the process of the conversion of hydrocarbon molecules in to carboxylic acids. As we’ve said before, higher temperatures can reduce the life of the hydraulic oil as it quickens the oxidation process. The by-products made from oxidation eventually form a varnish, which has the consequence of sticking servo valves and sludge, which would build up and block filters and suction strainers. If oxidation becomes a big issue, changing the oil immediately is the best course of action.
Water contamination is the most common form of contamination in hydraulic oil (see Water in Hydraulic Oil). Water is harmful to components because it doesn’t lubricate the surfaces and can cause wear. Corrosion may also occur if the water reacts to the additives in the oil. Rusting can also occur to component interiors, again accelerating the oxidation process.
If contamination arises in the air, oxidation can occur, adding to the viscosity of the oil. Over a long period of time, this can also varnish the surfaces. The contamination in the air may cause pumps to cavitate as the air in the oil dissolves due to the heat, which can damage the pump.
Other hydraulic oil contaminants may include dirt, metal particles and soot. They can cause corrosion on component surfaces and low viscosity, with lower viscosity reducing lubrication effectiveness.
All of the conditions mentioned above can have a detrimental effect on hydraulic oil life. Although there is no guaranteed way to make it last a lifetime, there are ways to make your hydraulic oil more cost-effective:
1. Ensure that any oil you have in your system is of high quality and from a supplier who can provide technical support when needed;
2. Keep an eye on operation conditions. Make sure the fluid is always kept clean;
3. Always ensure oil is changed if oxidation or contamination become too much.
Whilst there are ways the user can help preserve hydraulic oil life, there are also various methods of ensuring long hydraulic oil life within the oil itself, one of which is to use additives. The additives used in the hydraulic oil are dependent on what the oil is used for in the system. This allows the hydraulic oil to perform in diverse conditions.
- Anti-wear: lengthens the service life of hydraulic components and machinery;
- Cold flow: these additives enable a system to operate in extremely cold environments;
- Anti-foaming: an anti-foaming agent for hydraulic oil reduces foaming within the fluid which is sometimes caused by detergents. This foaming can reduce the lubricating quality of the product thus causing damage;
- Anti-oxidant: allows for longer periods of use without an oil change and also reduces sludge deposits;
- Anti-rust: forms a protective coating which reduces the risk of rust damage from oxygen contact.
Hydraulic filters and hydraulic oil life:
A hydraulic filter is an essential component of any hydraulic system; selecting the right hydraulic filter is absolutely vital to protect hydraulic oil life and ensure that particle contaminants are removed from the hydraulic fluid before components are jammed or damaged through abrasive wear.
As a leading hydraulic equipment supplier we have widespread, competitive access to a range of hydraulic filter manufacturers from around the world, including: Argo Hytos, Donaldson, Eaton Vickers, Hydac, Ikron, MP Filtri and Parker hydraulic filters.
Our team has over 75 years’ of technical experience between them and, as our library of customer testimonials shows, they know their stuff!