Hard particles in lubricating or fluid power systems may have a detrimental effect on machinery as they can cause operating components to wear, or may accelerate degradation of the lubrication properties of the fluid.
Assessment of the number and size of particles in the fluid is a useful component of in-service condition monitoring for these systems. It is used to assess what actions are required and can prevent damage of equipment as part of a preventative maintenance program, which saves on replacement costs.
Including particle count analysis as part of an in-service condition monitoring program will assist with making costly decisions regarding maintenance of the system such as:
- Is installation an off-line recirculating filtration unit required to extend the life of the product?
- Are there damaged parts that require replacement prior to a complete shutdown event?
- Does the hydraulic fluid require replacing?
During particle count analysis, particles within the fluid are sorted into “bins” based on the size of the particle in micrometers (µm). This total count is monitored over time for trend analysis. Some bin sizes are required for generating an ISO Cleanliness code, according to ISO 4406. These bins are ≥4 µm, ≥6 µm, and ≥14 µm.
ALS strives to ensure the reliability services offered to clients are at the highest possible standard. Recently there have been a number of improvements made to the particle count in-service condition monitoring program. Laboratories have purchased updated particle count analysis equipment that offers improved precision and accuracy compared to traditional instruments. Particle count testing has been historically associated with an increased uncertainty due to interferences from water, varnish, and suspended liquid additives. Particles may also quickly settle when not continuously mixed. The updated technology addresses all these concerns and also includes increased monitoring of results to ensure the improved accuracy and precision is maintained.
There have also been improvements to the reporting of results to clients. Previously, ALS reported ≥23 µm and ≥50 µm bin sizes. A year ago, ALS made the decision to change these bin sizes to the ≥21 µm and ≥38 µm as required by ASTM D7647 for client reporting. To ensure that clients had sufficient time to update in-service trend monitoring programs, all 7 bins were reported simultaneously for one year. Clients were informed of the change at the beginning and end of the year.
These examples demonstrate how ALS understands that in order to provide a high degree of confidence in the services provided, we must stay current with both technology and regulatory requirements that directly impact our clients. We remain committed to being recognized as the leading asset reliability testing service. Contact ALS Tribology for more information.
Carol Gebhart, BSc. Hon., MSc., CMQ/OE