Did you know that the number one cause of failure in a servo valve is due to contamination?

Below is a question we hear commonly when speaking with customers on their valve failures, and some answers that my help you. While no system is contamination free, an understanding of where contamination can come from will help you in controlling this problem.

Question: How does contamination enter my hydraulic system?

Answer: While there are a number of ways contamination can enter a hydraulic system, here are examples of a few of the more common causes.

• Breather caps - Most Hydraulic systems are fitted with breather caps for adding fluid to your reservoir, and to allow for thermal expansion and retraction as the temperature in your oil changes. But these breather caps can allow moisture, (humidity and condensation), as well as particles to enter the reservoir when this thermal expansion occurs.
• System Filters - Too often we see valves come in and the 1st stage filter is plugged with strands of fiber. These fibers can come from poor filter media in system filters that have broken loose due to pulsations in system pressure that are inherit in hydraulic systems.
• Cylinders – Cylinders can actually pull contaminates into the system oil by having the cylinder rod exposed to environmental contaminants.

Example of a first staged filter plugged with rubber contamination

Example of a first staged filter plugged with fiber strands

The above is only a couple of examples on how contamination can enter your hydraulic fluid. By better understanding and controlling this will lead to not only longer servo valve life, but also costly repairs when they do eventually fail.