Fluid Power Industry: Going Green

摘要

Ensuring responsible use of lubricants to avoid environmental damage is an ongoing responsibility of those who work in the fluid power industry. As fluid power engineers working in a variety of markets look to use more environmentally safe fluids, it is important to understand the benefits and constraints of the various types of biodegradable fluids available. This article will examine differentiators for all readily biodegradable fluids. (Note: Only "readily biodegradable" fluids, which break down quickly when they enter the environment, were considered for this study. "Inherently biodegradable" fluids, which require long-term remediation due to environmental persistence, were not considered.) The following is a summary of the types of readily biodegradable fluids and the results found for each fluid. There are four main classifications of environmentally preferable fluids as defined by ISO 6743/4: HETG vegetable-based, HEES ester-based, HEPG glycol-based, and HEPR PAO-based. Early work in the field focused on lubricants made from vegetable oils (natural esters or HETG). Vegetable-based fluids are readily biodegradable, but their performance is most suited to cool and dry operating conditions. Equipment operators must take care to ensure that such parameter boundaries are not violated. HETG fluids can typically only withstand operating temperatures under 180 ℉-200 ℉. As a result, vegetable-based fluids, when exposed to heat, will rapidly oxidize and therefore will have a limited life expectancy. Another issue with the vegetable-based fluids is that they become unstable when exposed to wet environments or contaminated with water. These fluids should be utilized in light-duty applications with controlled environments and relatively short change-out intervals.