Maintenance Technology August 2015 - (Page 36)

LUBRICATION STRATEGIES Keep Hydraulic Fluids Contaminant Free Hydraulic systems rely on vital fluids to transfer and amplify power and lubricate critical components. Protecting those fluids from contamination should be a top priority. Ken Bannister, CMRP, MLE Contributing Editor DESPITE THEIR COMPLEXITY, hydraulic systems are very forgiving beasts-almost too forgiving for their own good. They'll tend to perform inefficiently for a long time before catastrophic failure occurs. Unfortunately, this forgiving nature can foster a widespread, apathetic approach toward failure prevention, efficiency optimization, and service life-cycle management. Fluid is the most important part of any hydraulic system and when systems fail, the cause is most often related to fluid/fluid contamination. Those failures usually take other critical equipment and processes with them. Exorcise the "big three" Understanding how contaminants enter a hydraulic system is key to development of an effective maintenance strategy. 36 | MAINTENANCE TECHNOLOGY Hydraulic-fluid contamination comes in three major forms: solid particulate, water, and air. All of these can seriously affect the fluid and the equipment components it serves. Maintaining hydraulic fluids in optimum condition requires measuring, controlling, and preventing the introduction of these contaminants. Since contamination in any form can be inherent and induced, understanding how the three types enter a system is important in developing effective preventive-maintenance (PM) strategies. Solid-particulate contamination. Hydraulic system components are designed to operate with tolerances that can be as close as 1.5 microns. Solid particulate most often manifests itself as grit or dirt that, if allowed into a system, can be extremely damaging to bearing surfaces and hydraulic seals. The solid particles, which can be more than 100 microns in size, will set up in a three-body abrasion state and easily score the mated machined surfaces, creating rapid bearing and component-surface wear, leading to unwanted fluid bypass that reduces operating efficiency. Solids contamination will also cause valve stiction, increased fluid viscosity, and unwanted fluid leakage through nicked and scored cylinder seals. If your equipment is new or rebuilt, solids contamination in the form of leftover dirt or swarf from the manufacturing/ rebuild process could be present in the hydraulic lines. Prior to initial startup, lines should be wad cleaned, existing oil flushed from the system, and new, correct-viscosity fluid added. Many end-users are unaware that solids-contamination levels can be excessive in new oil supplied from the manufacturer or introduced by the supplier if bulk-transferred through dirty transfer hoses and equipment. When receiving new-especially bulk-oil, always perform an oil analysis to detect solids and water contamination. While new oil can often be found at a 19/17/14 cleanliness AUGUST 2015

Table of Contents for the Digital Edition of Maintenance Technology August 2015

My Take
For On The Floor
Industry News
Ultrasound: Aural Intelligence
Excellence in Action
Cool Advice on Hot Motors
Step Up to Greater Electrical Awareness
Keep Hydraulic Fluids Contamination Free
Five Steps to Workplace Desirability
Put a Good Base Under Your Pumps
QR-Code POI System for Quick Problem Solving
Contrarian View
Ad Index

Maintenance Technology August 2015