Lubrication - Part B (160201fB) Flashcards
Why is it important not to allow the oil level in an oil bath lubrication system to go above the centreline of the lowest rolling element?
To avoid churning, which would produce extra heat
What are two disadvantages of a bottle lubricator?
- Oil is not recirculated, but wasted
- It is restricted to uses where surface speeds are low (under 1000 RPM)
Can a wick feed lubricator be mounted below a bearing?
Yes
Should a constant level lubricator be mounted on the left or the right side of the housing if the rotation is clockwise?
Left side
What are four disadvantages of ring or chain oilers?
- Ring oilers are limited to shafts under 4 inches.
- Rings or chains can wear through and break without being noticed, leading to lubrication failure.
- They only work on horizontal shafts.
- They only work dependable on stationary equipment.
What are two important functions of a sight glass on a lubrication system?
- To monitor the oil level
- To monitor the condition of the oil
What component should be added to a pressure lubricating system if the oil is exposed to temperatures above 55°C?
A heat exchanger
What are three (3) limitations of an oil mist system?
- The oil must be kept above 20°C to keep it in suspension
- It can only be used where oil mist will not endanger health
- It is not suitable for high-temperature applications, as oil mist oxidizes more rapidly
What are three advantages of an air-oil system?
- It pressurizes the bearing housings, which prevents contaminants from entering
- It consumes very little oil
- It promotes long bearing life by delivering cool, clean oil in the correct amount
Where would a block lubricating system normally be used?
On large stationary engine and reciprocating compressors
Should a constant level lubricator be mounted on the left or the right side of the housing if the rotation is clockwise?
Left side
What is the recommended level of oil in a bearing?
No higher than halfway up the lowest rolling element.
Which is the best one to use if you need it bonded to a surface permanently (oil, grease, solid lubricants)?
Solid lubricants
Which solid lubricant has the greater load-carrying capacity, graphite or Teflon?
Graphite
Which is the best one to use to carry away heat (oil, grease, solid lubricants)?
Oil
Which is the best one to use to flush away contaminants (oil, grease, solid lubricants)?
Oil
Which lubricant may be used where oil and grease are not adequate?
Solid lubricants
What colour is graphite type solid lubricant?
Grey-black
What are the three (3) types of solid lubricants often used in industry?
- Graphite
- PTFE (Teflon)
- Molybdenum disulphide
How full should the housing be for a grease-lubed bearing?
Housing should not be more than 1/3 full
Give two advantages of centralized lube systems.
- Eliminates the risk of contamination from dirt on a grease gun nozzle or dirt getting into grease cup when you refill it.
- Metering valves ensure that the correct quantity of lubricant is applied.
What is necessary before injecting grease into a grease nipple?
Clean the grease fitting thoroughly before attaching the grease gun.
What types of grease cups are considered automatic?
Spring-loaded and electric timer style.
What is a disadvantage of a singe point grease application system?
When there is a large number of lubrication point, in which case more time is required to monitor the process.
What is an advantage of a single point grease application system?
Simple, compact and inexpensive.
What is the purpose of having EP additives in a grease?
To prevent damage from welding at the tips of the asperities on the loaded surfaces.
What does grease consistency depend on?
Type of thickener, quantity of thickener and temperature.
Why should you not use grease with different thickeners?
Mixing results in a softer grease with a lower usable operating temperature.
Why should you not use grease with different thickeners?
Mixing results in a softer grease with a lower usable operating temperature.
What is one of the oldest grease thickeners used?
Soap
Why should oil samples be taken at regular intervals for testing?
To establish a performance trend for the oil and a wear rate for the machine
What is drop point referring to in a grease?
This is the lowest temperature at which the lubricant begins to drip from grease.
How does a grease thickener work?
The thickener acts like a sponge to hold the lubricant and also controls the flow of the grease to the area to be lubricated.
What is a grease?
Grease is a liquid lubricant mixed with a thickener.
What are two advantages in sending used oil for re-refining?
- It prevents possible contamination of the environment
- It provides a supply of top-quality oil
Does new oil meet manufacturers’ recommended standards for bearings?
No
What are the two main safety concerns when handling or storing lubricants?
- Cancer
- Fire
Give three reasons for on-line flushing.
- To remove contaminants
- To remove preservatives
- To reduce the particle count in new oil
Is it best to take an oil sample immediately after a machine has been running at its normal operating temperature or after it has cooled down?
Immediately after running, to establish a wear rate for the machine
How can you tell if the particle count in a lab report is excessive or not?
By comparing the count to the target cleanliness levels specified by the manufacturer
What does the silicone particle count indicate?
The amount of dirt ingested through the seals and breather
How is the wear rate of components determined?
It is based on a change in spectroscopy numbers
Does the number of parts per million on a spectroscopy report indicate the actual amount of wear on components?
No
Proper level of lubricant in a rolling element bearing is ________________________.
halfway up the lowest rolling element.
Movement of oil in a wick feed oiler is by __________.
capillary action
A measure of grease stiffness is referred to as _________.
consistency.
Thickeners for grease can be made from compounds that are classified chemically as _________.
soaps.
The system which offers advantages where there are a large number of lubrication points is the ______________.
centralized lubrication system.
