LUBRICATION PRINCIPLES WEEK 1 Flashcards
TERMINAL OBJECTIVE:
1 Under all operating conditions, describe the purpose and necessity, the theory, the types,
the storage concerns, the safety concerns, and the environmental concerns of lubrication
products in accordance with Station Documents and Procedures.
BE ABLE TO ANSWER ALL OTHER CARDS
1.1 State the basic purposes of lubrication.
• Reduce friction
• Reduce wear
• Reduce abrasive wear
• Dampen shock
• Provide cooling
• Reduce corrosion
• Minimize intrusion of contaminates
1.2 State the definition of friction.
a force which acts between two surfaces to resist their sliding or rolling across
each other.
1.3 Describe the different types of friction
Static Friction
Static Friction exists between a body at rest and the surface upon which it rests. Static friction
must be overcome to start a body in motion.
Kinetic Friction
Kinetic Friction is defined as friction that exists between moving bodies or between one moving
body and a stationary surface. Kinetic friction must be overcome to keep a body in motion.
1.4 Explain the different types of lubricant films.
• Dry Film
• Mixed Film
• Boundary Film
• Full Film
Hydrodynamic: Lubricant film maintains the separation of loaded surfaces due to its ability to
exert a higher pressure and viscosity as the load increases.
Hydrostatic: Lubricant film provided from an outside source (bearing lift pump) maintains the
separation of the loaded surfaces. Used for slow, heavy loads or to cut down starting
friction by lifting journal off the bearing surface. For example, Main Turbine lift oil system
used prior to startup or shutdown.
1.5 Explain the Langmuir Theory of Lubrication and development of an oil wedge.
As lubricant is forced into the small wedge below the load, its
viscosity increases, causing opposing fluid pressure to build and begin separating journal and
bearing surfaces.
1.6 Describe the general classifications of lubricants
• Liquid
• Semisolid
• Solid
• Gas
1.7 Describe the major properties of oil.
Viscosity is the tendency of a fluid to resist flow due to internal friction of liquid molecules moving
across each other.
Absolute or Dynamic Viscosity
Kinematic Viscosity
Pour Point
Flash Point, Fire Point, Auto-Ignition Point
Neutralization Number
Demulsibility
Precipitation Number
1.8 Describe the major properties of grease
- Hardness
Hardness is analogous to viscosity rating for fluid lubricant. Greases rated by numbering system
(0-6) used to show firmness at room temperature. They are measured using device called
Penetrometer, which measures how far a pointed cone will sink into a grease sample in five
seconds. - Dropping Point
Dropping points differences are mainly due to the soaps which grease contains. It is defined as
the temperature at which grease will change from a semi-solid to a liquid form. Sometimes it is
called the melting point. It is an important test to determine the kind of grease to use for a
particular application. - Pumpability
Pumpability measures the ease with which grease can be pumped. This is an especially
important characteristic to be aware of in centralized grease systems, where a pump must
distribute grease to numerous machine bearings. - Water Resistance
In some applications, water cannot be prevented from coming in contact with moving parts of
machinery being lubricated with grease. Some greases dissolve in water (e.g. soda soap) and
others do not (e.g. calcium or lithium soaps). - Stability
Stability is the ability to retain original hardness, which is important in greases used to lubricate
bearings. Grease will be described as very stable if it will stay packed into an antifriction for a
long period of time without becoming soft and leaking out.
1.9 Describe lubrication systems and methods
- Manual Lubrication
- Gravity or Drip-Feed Lubrication
- Natural Lubrication
- Splash Oilers
- Ring Oiler
- Pressure Lubrication (forced feed) Systems
- Wet Sump System
- Dry Sump System
- Air Line Lubricators
1.10 Describe methods of oil purification.
GRAVITY SETTLING,
CENTRIFUGE,
LUBE OIL CONDITIONER (TURBO TOC), VARNISH REMOVAL SYSTEM
1.11 Describe symptoms of improper lubrication
Telltale signs of improper lubrication include high temperature, vibration, noisy components, and
eventual failure
1.12 Describe proper methods for lubricant storage.
Inside Storage:
Storage lockers
Fireproof constructed rooms
All lubricants easily accessible
Markings clearly visible
Use older lubricants first
Outside Storage:
55-gallon drums placed on their sides and covered
Drums raised off the ground.
1.13 Describe safety precautions to follow when handling lubricants.
Smoking prohibited in lubricant storage areas
Provide adequate ventilation
Wear gloves, long sleeved shirts to minimize skin contact
Wear safety glasses or goggles to avoid eye contact
1.14 Describe the environmental hazards associated with lubricating oil or lubricating oil
See oil where it shouldn’t be? Clean it up.
Pigs to contain or soak up puddles
Oil absorbent containers to put under small leaks.
Larger spills may require respirator/protective clothing
Notify the Environmental Department for:
Surface soil contamination
Ground water contamination
Air pollution
