Lubrication lowers friction and enables moving machine parts to slide past each other smoothly. An automatic lubrication system offers numerous advantages over manual lubrication. In order to maximize the efficiency and life expectancy of any rotating equipment, lubrication is essential.
A study conducted by SKF found that over 50% of bearing failures stem from improper lubrication. Learn more about how it leads to extended equipment life, reduced wear, and smaller maintenance bills.
Well, in this reading, I’ll be exploring what Lubrication is, diagram, types, its roles, disadvantages & how to use.
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Contents
What is Lubrication?
Lubrication is the control of friction and wear by the introduction of a friction-reducing film between moving surfaces in contact. The act of using a lubricant to minimize wear and tear and friction between two surfaces is known as lubrication.
Within the topic of tribology is the study of lubrication, the lubricant used can be a fluid, solid, or plastic substance. Many different substances can be used to lubricate a surface.
Understanding The Lubrication
Additives to lubricants that contain oil can augment, increase, or decrease the qualities of the basic oil. Depending on the kind of oil and the intended usage, different amounts of additives are needed. For example, a dispersant may be added to engine oil.
Insoluble material is kept clumped together by a dispersant so that it may be filtered out during circulation. A viscosity index (VI) improver may be applied to situations that experience temperature extremes, ranging from cold to hot.
Through this technique, the oil’s viscosity is altered while retaining its high-temperature characteristics, improving its flow in cold weather. The one issue with additives is that they can run out, and often, the oil volume needs to be increased in order to replenish them to adequate levels.
Diagram Of Lubrication
The Role Of Lubricant
- Reduce friction
- Prevent wear
- Protect the equipment from corrosion
- Control temperature (dissipate heat)
- Control contamination (carry contaminants to a filter or sump)
- Transmit power (hydraulics)
- Provide a fluid seal
How Lubrication Works
In order for mechanical systems like pumps, cams, bearings, turbines, gears, roller chains, cutting tools, etc. to function properly, lubrication is necessary. Without it, the pressure between adjacent surfaces would be too high to quickly cause surface damage, which in a condition where the surfaces are coarse enough could literally weld them together, resulting in seizures.
The film that forms between the piston and the cylinder wall in some applications, like piston engines, also acts as a seal to keep combustion gasses from leaking into the crankcase.
There would be an oil pump and an oil filter if an engine needed pressured lubrication for things like simple bearings. Splash lubrication would work quite well on older engines (such a Sab maritime diesel), when pressured feed was not necessary.
Types of Lubrication
There are three different types of lubrication: boundary, mixed and full film. Each type is different, but they all rely on a lubricant and the additives within the oils to protect against wear.
These are the major different types of lubrication listed: Mixed lubrication, Electrohydrodynamic lubrication, Boundary lubrication, Fluid Film Lubrication
1. Mixed Lubrication
This regime is between the boundary lubrication regime and the whole film electrohydrodynamic regime. Although the lubricant layer formed is insufficient to fully separate the bodies, the hydrodynamic effects are significant.
2. Electrohydrodynamic Lubrication
Elastic stresses at the contact occur mostly on non-conforming surfaces or under greater load circumstances in the bodies. A load-bearing area created by this strain offers the fluid a nearly parallel gap to pass through. The contacting bodies’ motion creates a flow-induced pressure that serves as the bearing force throughout the contact region, just like in hydrodynamic lubrication.
Such high pressure regimes can cause a significant increase in the fluid’s viscosity, the lubricant film that is produced during full film electrohydrodynamic lubrication totally isolates the surfaces. This lubrication regime is an example of fluid-structure interaction because of the close relationship between the hydrodynamic action of the lubricant and the elastic deformation of interacting solids.
3. Boundary Lubrication
The consequences of hydrodynamics are minimal. At their asperities, the bodies come into closer contact; some asperities break off due to stick-slip, a phenomenon caused by the heat created by the local tensions. Another definition of boundary lubrication is the regime when the load is supported by the surface asperities rather than the lubricant.
When the temperature and pressure are raised, the lubricant’s chemically reactive components react with the contact surface to form a boundary film—a highly resilient, tenacious layer that forms on moving solid surfaces and can support a load without experiencing significant wear or breakdown.
4. Fluid Film Lubrication
By enabling the lubricant to completely support the load within the space or gap between the components that are moving relative to one another due to viscous forces, the lubrication regime known as “fluid film lubrication” avoids solid-solid contact.
The lubricating layer is maintained in hydrodynamic lubrication by the bearing’s design and the motion of the contacting surfaces, which circulate fluid around the bearing. This bearing design may wear whether it is reversed, stopped, or started when the lubricating layer deteriorates.
Disadvantages Of Lubrication
- Excess heat build-up.
- Product spoilage.
- Bearing seal damage.
- Clean-up issues.
- Increased downtime.