Troubleshooting Hydraulic Strainer Issues

Noria Corporation

One of our hydraulic systems just had a strainer blow out. How could this have happened?

Hydraulic systems undergo several pressures. Where the strainer is placed within the system will decide the pressure it will experience. Obviously, if the strainer is on the return side, it will endure less system pressure and may potentially last longer.

Regardless of the placement of the strainer, one possible cause of failure is contamination. A root-cause analysis should be performed to determine the reason for the failure. Finding the root cause will help prevent any future problems related to this particular incident. If contaminants are found to be the cause after completion of the analysis, then you will need to develop a plan to remove them as soon as possible.

Keep in mind that contamination can be anything that comes into the system, excluding the lubricant or properties of the lubricant, that can lead to surface degradation and oxidation. Contamination is generally the most common cause of failures.

Typical contaminants include solid particles, moisture, air, heat, antifreeze, fuel, etc. It is essential to determine what type of contamination you have in your system because each of these contaminants has a different means by which it affects the material it comes in contact with. For example, water is a central promoter of rust, which will weaken the integrity of the material and eventually cause it to fail.

There are many ways for contaminants to get into a system, such as through new oil, ventilation and breathers, seals, wear generation, service and manufacturing debris, and filter dumping.

To get contaminants out of a system quickly, you should utilize proper filters for circulating systems, off-line filters for some splash/bath-lubricated machines, portable filters for other machines, appropriate sump and reservoir management, and timely filter servicing.

I would also strongly recommend that an appropriate oil analysis be performed. Make sure that you are using the correct test slate when requesting oil analysis testing. This test slate should answer all the questions that are critical to your reliability goals.

It is equally important to have a qualified oil analyst within your organization properly review the report and make any recommendations needed to remove contaminants. Remember, the cost of excluding a gram of dirt is probably only about 10 percent of what it will cost you once it gets into your oil.

Subscribe to Machinery Lubrication