The hydraulic system is the heart of a modern drill rig. It powers the rock drill, the feed, the boom and the tramming functions, and almost every one of those components works with very tight internal clearances. That is why the condition of the hydraulic oil matters so much. Filtration specialist Schroeder Industries states that over 70% of all hydraulic system failures are caused by contaminants in the fluid. On a rig working in dust, mud and water every day, keeping the oil clean is one of the most effective ways to protect expensive components and avoid unplanned downtime.
Where contamination comes from
- Built-in contamination. New systems and freshly rebuilt components can carry particles left over from manufacturing and assembly.
- Ingested contamination. Dirt enters from outside through inefficient air breathers, worn cylinder rod seals and airborne dust during servicing, which is a real risk on site.
- Generated contamination. Friction and heat inside pumps, motors and valves produce wear particles that circulate and accelerate further wear.
- New oil and top-ups. Fresh fluid added to the tank can also bring particles into the circuit if it is not filtered on the way in.
How cleanliness is measured
Oil cleanliness is usually expressed with the ISO 4406 code. It uses three numbers that describe how many particles of at least 4, 6 and 14 microns are found in one millilitre of fluid. For example, a result of 19/15/11 describes one sample: the lower the numbers, the cleaner the oil. Tracking this code over time shows whether contamination is under control or getting worse.
Practical tips for drill rig owners
- Filter oil on the way in. Pass new and make-up oil through a filter instead of pouring it straight into the tank.
- Know your most sensitive component. Set the target cleanliness level for the part with the tightest tolerances, typically the rock drill and its control valves.
- Use good breathers and rod wipers. Efficient air breathers and effective wiper seals on cylinders keep site dust out of the system.
- Keep servicing clean. Cap open hoses and ports, clean fittings before opening them and avoid working in the wind and dust where possible.
- Sample and count particles regularly. Routine oil sampling and particle counting reveal problems early, and filter indicators show when elements need changing.
- Use correct filter elements. Choose filter media that can actually reach the target cleanliness level for your system.
Clean oil does not show up on a production report, but dirty oil does: in worn pumps, sticking valves and rock drill repairs. A simple, consistent contamination control routine costs far less than the components it protects.
At Razor Spare, we supply high-quality alternative spare parts for rock drilling equipment, including hydraulic and service components that help keep your rigs running reliably.
Sources:
Schroeder Industries – “Contamination Control Fundamentals” (Section 1, Principles of Filtration). schroederindustries.com
This article is an original summary prepared by Razor Spare based on the sources above.