Proper contamination control is at the foundation of a profitable lubrication program. It doesn’t take a significant number of particles in a lubricant for bearing life to be affected, which is why maintenance personnel should be relentless in identifying and addressing all sources of ingression.
Contamination control can be divided into two main parts: exclusion and removal. Since neither method is sufficient on its own, you must consider both for an effective contamination control strategy.
Externally ingested contaminants, internally generated contaminants and contaminants created by human interaction are the primary sources of contamination in a system. Let’s dive into a few examples of each and how to avoid them.
Externally Ingested Contaminants
For external exclusion, it is critical to understand the possible sources of contaminants in the system. Possible ingression points include:
- Or other inlets
Poor seal design, worn seal materials, and operational or environmental conditions can all be held responsible for introducing contaminants and should be inspected regularly. Failed shaft seal points may ingress external contaminants or internal process materials. For hydraulic components, contaminants damage the seal materials during extended operation and wiper and rod seals inevitably leak both externally and internally.
Road dust, soil, rock dust, moisture or other contaminants can also enter the system through any breathable headspace. Even when a machine is equipped with an appropriate breather, gaps in the hatches, ports, etc., can allow air to be “breathed” in within these areas of least resistance.
Internally Generated Contaminants
A lubricant’s constituents can turn into insolubles, sludge, additive fallout, and more if left to thermally degrade or oxidize over time. Preventing lubricant oxidation requires minimizing the availability of air and controlling heat. It is important to remember that heat alone will not lead to oxidation—it can only expedite the reaction process between two unstable elements.
Air control can be achieved by keeping your bearing seals in good shape and ensuring all fittings and connections are kept tight. To reduce heat, always use the correct viscosity grade and keep vibration at a minimum.
Another instance of an internally generated contaminant is rust, which is a result of water corroding iron and forming red-iron oxides. Fibers from seals, hoses, filters, or other materials can also leave contaminants to invade the system. Lastly, friction from insufficient lubrication can lead to particles forming due to adhesive, abrasive, or fatigue wear. The best thing you can do is to get lubrication right by calculating the correct regrease intervals and avoid under-or over-lubricating the bearing. The OnTrak SmartLube takes the stress out of this by monitoring friction constantly and automatically regreasing bearings at the right time with the right amount.
Contrary to popular belief, new lubricants are usually not clean and can introduce a variety of contaminants. Likewise, as machines require internal work, such as replacing bearings and seals, the fluid reservoir may be exposed. Machining swarf, welding spatter and sealants or adhesive materials are all examples of debris that can be left behind from human interactions with the equipment.
It is also possible for dust and particles to be present in the air when the operator is dispensing lubricant into a bearing. Using a single-point lubricator keeps grease in an enclosed space until it is distributed.
Creating a holistic contamination control strategy is crucial to long bearing life and healthy lubricants. A combination of the right lubrication technology and filter equipment, proper lubrication practices and regular oil analysis can minimize contaminants and boost uptime.
Source: UE Systems