Biodegradable fluids

Due to the growing interest in biodegradable fluids, they are becoming increasingly important in the lifting sector.

Biodegradable fluids can be classified into 3 categories according to their base:

HEPG (Glycol-based fluids)

• Wide temperature range (from -45oC to 100oC).
• Very stable against aging.
• NBR and FKM gaskets are compatible.
• Moderate change in viscosity with temperature.
• Soluble in water.
• They cannot be mixed with mineral fluids or with HEES and HETG types.
• It is recommended to thoroughly clean the pipes when changing mineral oil.
• It can dissolve paints.
• Care must be taken with the compatibility of materials (for example, materials containing zinc must not be used).
• Density > 1,100 kg/m3 possible design changes.

HETG (Plant-based fluids)

• Can be mixed with mineral fluids.
• Standard gasket materials are compatible (e.g. NBR or FKM).
• Good lubricating properties.
• Fluid resistant paint.
• Viscosity changes with temperature are moderate.
• Limited temperature range (from -25oC to 70oC).
• The maximum temperature must not be exceeded.
• Limited life.
• Sensitive to ultraviolet rays and ozone.
• Care must be taken with water absorption.

HEES (Ester-based synthetic fluids)

• Wide temperature range (from -30oC to 90oC or over 100oC with some variants).
• Good service life.
• They can be mixed with mineral fluids.
• Compatible with normal gasket materials (FKM and NBR recommended).
• Fluid resistant machine paints.
• Viscosity changes with temperature are moderate.
• Good lubricating properties.
• Danger of hydrolysis with water absorption (filters, dryers, occlusion).

Source: Industrial Tube Fittings – Europe. Technical Manual/Catalogue 4100-8/EN . Author: Parker

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