Hydraulic Fluid Analysis: Avoiding the Potential Pitfalls

By Jim Fitch and J.B. Allred
Hydraulics and Pneumatics Magazine

Analysis of hydraulic fluids, if done properly, can suggest maintenance procedures to improve hydraulic equipment reliability and extend system life. Significant cost savings can result. Where to take a sample There are two types of fluid sampling: static and dynamic. Static sampling involves extracting a fluid sample from a reservoir or a dead zone, where there is slight fluid movement. Little useful information is gained from static sampling because: • contaminant concentration gradients exist within static fluids. Water and particles tend to segregate and settle due to gravity. Therefore, samples taken from different sections within the static container yield completely different results, and • particles from reservoirs may describe system histories, but provide little information on what is happening now. Large reservoir volumes dampen out dynamic changes and conditions within the system.