During the holidays, Flow Dynamics and Automation completed a full-scale field flush on a large extrusion press operating at extreme flow demands. The system runs continuously at 300–400 GPM, powered by multiple Oilgear PVV piston pumps driven by 250-HP motors. Systems of this size require massive reservoirs and large DIN poppet valves (63 mm and 80 mm) to control flow to the cylinders.

The challenge began after several catastrophic pump failures released millions of metallic particles into the hydraulic system. With no pressure filtration protecting the manifolds, contamination flowed directly into logic manifolds and valves. These particles bridged critical clearances between moving components, acting like a lapping compound. As wear increased, even more particles were generated—creating a destructive chain reaction.

To put the problem in perspective:

• Most of the damaging contamination measured 5–15 microns

• The human eye cannot detect anything smaller than 40 microns
  In other words, the most destructive particles were completely invisible.

At this stage, draining the oil alone would not solve the problem. Sub-micron particles were embedded throughout the manifold system and could not be flushed out conventionally. The only viable solution was a complete system teardown.

Our team disassembled every poppet, sleeve, directional valve, and cartridge valve. Each component was individually cleaned, flushed, and inspected. Some valves were too severely damaged and required replacement.

While valve work was underway, additional technicians transferred all oil from the operational tanks into dedicated cleaning tanks. Every reservoir was manually cleaned and wiped down to ensure zero contamination. Suction screens were removed entirely and not recommended for reinstallation. At the same time, the customer’s oil was circulated through 39-inch flushing filters with 6-micron elements rated at Beta 6 = 1000, ensuring effective silt control.

All activities—component cleaning, tank restoration, and oil filtration—were executed simultaneously to prepare for system restart. This comprehensive approach was the only way to return the system to proper operating specifications and prevent future failures.

The entire flush took seven days. The press restarted without issue.

Clean oil matters. When contamination is controlled, hydraulics perform exactly as they’re designed to.

Key Takeaways

• 5-micron particles are invisible to the naked eye but can destroy hydraulic and lube systems

• ISO cleanliness codes quantify contamination size and volume

• Filter media must be inorganic, well-bonded, and properly supported

• Beta ratings provide the most accurate way to evaluate filtration performance

• Long filter life is achieved through effective silt control

• Proper housing strength and placement are critical

• Differential pressure indicators maximize service life

• Water is contamination and must be removed from hydraulic systems

If any of this sounds familiar or hits a nerve, call Flow Dynamics.