Purifiers Flashcards
Explain the importance of using the correct size gravity disc for a centrifugal lubricating oil separator
Gravity discs are very important for optimal separation as it controls the oil-water interface.
- Gravity disc is too large, the interface will move outwards towards the water outlet allowing oil to to escape with the water.
- Gravity disc too small, the interface will move inwards towards the oil outlet allowing water to escape alongside clean oil
State the TWO factors that determine the size of the gravity disc to be used
- Specific Gravity/Density of the Fluid
- Specific Temperature
- Feed Rate to Purifier
Explain TWO factors that have an influence on the separating process within a centrifugal purifier
- Different density of oil and water
- Position of the oil-water interface
- Temperature of the fluid
Explain TWO reasons for a purifier not attaining full running speed
- Break has been left on
- Clutch shoes Worn
-Timing Belt Worn
State the function of the gravity disc
Gravity discs are very important for optimal separation as it controls the oil-water interface.
State the consequences of gravity disc too large
The interface will move outwards towards the water outlet allowing oil to to escape through the water outlet.
State the consequence of gravity disc too small
The interface will move inwards towards the oil outlet allowing water to escape alongside clean oil through the oil outlet.
State the function of the purifier
The purifiers function is to remove water and solid impurities from the oil.
State the function of the clarifier
The clarifiers function is to remove only solid impurities from the oil.
State TWO constructional differences found in the bowls of purifiers and clarifiers
CLARIFIER
- Doesn’t have a gravity disc as there’s no oil-water interface to maintain.
- Only has an oil outlet.
PURIFIER
- Does have a gravity disc as there’s a oil-water interface to maintain.
- Has both water and oil outlet.
Outline the separation process that occurs within centrifugal oil purifiers
Separation occurs due to different gravity’s.
1), Contaminated oil enters the purifier (typically heated before entry to reduce viscosity)
2), the contaminated oil is then spun at a very high RPM inside the bowl where it flows through a series of discs.
3), The centrifugal forces (generated by the high-speed rotation) amplify the small differences in specific gravity and separates the contaminated oil into 3 layers based on density.
4), Solids/Sludge moves outward toward the periphery of the bowl and collect in the sludge space.
5), Water forms a layer in-between the solids and oil due to its density being in the middle of the three.
6), Oil moves inward towards the centre of the bowl and rises towards the clean oil outlet as it is the lightest.
7), The gravity disc in the bowl maintain and control the oil-water interface for efficient separation.
Explain the change required to non ALCAP type purifier if it is to be used for an oil of lower density
Changing the gravity disc to a smaller one to maintain a proper oil-water interface, if left un changed oil will escape through the water outlet.
Describe with the aid of a sketch, the principles of a centrifugal separation as used in fuel and lubricating purifiers
INSERT SKETCH
- Separation by Density - It separates substances based on differences in specific gravities.
- High Speed Rotation - The bowl spins at a high RPM, generating strong centrifugal forces.
- Force Amplification - These forces amplify the difference in specific gravity separating them into three layers, heavier particles move outward while lighter ones move inward.
- Continuous Operation - Clean oil flows out form the centre, while water and sludge are discharger separately.
Outline the separation process that occurs within centrifugal oil purifiers
Separation occurs due to different gravity’s.
1), Contaminated oil enters the purifier (typically heated before entry to reduce viscosity)
2), the contaminated oil is then spun at a very high RPM inside the bowl where it flows through a series of discs.
3), The centrifugal forces (generated by the high-speed rotation) amplify the small differences in specific gravity and separates the contaminated oil into 3 layers based on density.
4), Solids/Sludge moves outward toward the periphery of the bowl and collect in the sludge space.
5), Water forms a layer in-between the solids and oil due to its density being in the middle of the three.
6), Oil moves inward towards the centre of the bowl and rises towards the clean oil outlet as it is the lightest.
7), The gravity disc in the bowl maintain and control the oil-water interface for efficient separation.
Explain the change required to non ALCAP type purifier if it is to be used for an oil of lower density
Changing the gravity disc to a smaller one to maintain a proper oil-water interface, if left un changed oil will escape through the water outlet.
