Eco-Friendly Hydraulic Fluids

Special design considerations are necessary when using biodegradable hydraulic fluids

Eco-Friendly Hydraulic FluidsNo company wants to risk the potential PR nightmare of having their name associated with environmental degradation. This applies to hydraulic fluid manufacturers as well as to the companies that use hydraulic equipment on a daily basis. While utilizing high-quality hydraulic hoses and connectors is an excellent way to reduce the potential for a fluid spill, you may also want to investigate the possibility of utilizing eco-friendly biodegradable hydraulic fluids in your system to further reduce the risk of environmental degradation.

Types of Biodegradable Hydraulic Fluids

There are four main types of biodegradable hydraulic fluids in use today:

HETG Fluids: Hydraulic Environmental Triglyceride fluids are highly biodegradable and non-toxic water-insoluble fluids made from soybean, sunflower, and Canola oils. They have excellent lubricity and offer protection against corrosion, but they break down and gum up quickly when used in high-temperature conditions and can thicken and gel at low temperatures.

HEES Fluids: Hydraulic Environmental Ester Synthetic fluids are derived from either petroleum or vegetable oils. They have high thermal and oxidative stability, good fluidity at low temperatures, and a long service life.

HEPG Fluids: Hydraulic Environmental Poly Glycol fluids are fire-resistant polymers that come in water-soluble and water-insoluble varieties. They have a broad operating temperature range of -20 to 80°C.

HEPR Fluids: Hydraulic Environmental Polyalphaolefin & Related fluids are water-insoluble synthetic hydrocarbon-based fluids. These fluids have good oxidation stability, corrosion protection, lubricity, and viscosity performance over a wide temperature range of -30 to 100°C.

System Design Considerations

The main issue with using eco-friendly fluids, aside from the higher cost of the fluids themselves, is that they are incompatible with many seal and gasket materials and may shorten the life of other hydraulic components or affect their performance. Some examples of affected components include:

Seals & Hoses: Fluorocarbon seals, hoses, rings, gaskets, etc. are often the best bet for use with biodegradable fluids, as traditional nitrile seals will typically wear out faster when used with these fluids.

Pumps: Most biodegradable fluids have a higher specific gravity than a standard hydraulic fluid. Therefore pumps and related parts such as inlets and overhead reservoirs may require adjustment in order to create positive inlet pressure, facilitate adequate suction, and prevent cavitation.

Breathers: Because many biodegradable fluids are susceptible to water contamination, it may be necessary to install water-absorbent breathers within the reservoir. Otherwise, the water contamination will cause the fluid to break down and lose its lubricity.

Filters: It is wise to use larger-capacity filters and change or clean them more frequently when using biodegradable fluids to ensure any contaminants produced by the breaking down of the fluids are captured.

Consult the Pros First

Before converting any hydraulic system to a non-petroleum fluid, it would be wise to consult the fluid manufacturer, the system manufacturer, and an expert hydraulic parts & repair provider like Bernell Hydraulics.