Contamination is the number one enemy of hydraulic systems. Studies show that over 75% of hydraulic failures are caused by contaminated fluid. A proper filtration strategy is not just about changing filters when they "look dirty"—it's a calculated science of maintaining ISO cleanliness codes to ensure component longevity.
Did You Know?
A hydraulic particle invisible to the naked eye (under 40 microns) is often the most damaging. Silt-sized particles (1-5 microns) can enter critical clearances in valves and pumps, causing silent, catastrophic failure over time.
1. When to Replace a Hydraulic Filter?
Replacing filters too early wastes money; replacing them too late destroys components. The only reliable method is using clogging indicators and adhering to a strict schedule.
1.1. Clogging Indicators
Modern filter housings are equipped with visual or electrical indicators. These measure the pressure drop (ΔP) across the element.
- Visual Indicators: Usually a pop-up button or gauge. Check these when the oil is at operating temperature, as cold oil is thicker and can give false positive readings.
- Electrical Switches: These send a signal to the PLC or control panel when the filter is nearing bypass. This is preferred for critical systems.
2. The Danger of Bypass Valves
Most hydraulic filters have a built-in safety mechanism called a bypass valve. If the filter is completely clogged, this valve opens to allow unfiltered oil to pass through, preventing the filter element from collapsing or the system from starving of oil.
The "Safe" Mode Trap
When a filter goes into bypass mode, you are effectively running with NO FILTRATION. Accumulated dirt acts like a sandblaster on your pumps and valves. Never ignore a clogging indicator.
3. Understanding Filter Ratings: Beta Ratio vs. Micron
Not all "10-micron" filters are created equal. The efficiency of a filter is defined by its Beta Ratio (β).
| Beta Ratio (β) | Efficiency Percentage | Quality Grade |
|---|---|---|
| β₂ = 2 | 50% | Relatively Poor (Nominal) |
| β₁₀ = 20 | 95% | Standard Protection |
| β₁₀₀₀ = 1000 | 99.9% | High Performance (Absolute) |
At BRS Proses, we recommend using high-quality glass fiber elements with a Beta ratio of >200 (absolute) for pressure and return lines to ensure maximum system protection.
4. Filter Replacement Best Practices
Follow these steps for a safe and effective filter change:
- Depressurize: Ensure the system is off and pressure is relieved.
- Clean the Area: Wipe the housing cap before opening it to prevent dirt ingress.
- Inspect Seals: Always replace O-rings and gaskets with the filter element.
- Do NOT Wash: Fiber elements are disposable. Do not attempt to wash and reuse them.
5. How BRS PROSES Can Help
We don't just sell filters; we sell reliability. Our team can analyze your system's ISO cleanliness targets and recommend the exact filtration strategy you need.
"The most expensive filter is the one that allows your pump to fail."
— BRS PROSES Engineering Team