Manual application of oil
An oil can is used in simple cases by smearing oil on the surfaces to be lubricated.
Oil can also be injected onto the surfaces by a hand pumped oil can.
OIL SUMP LUBRICATION BASICS
There are many types of lubrication methods to choose from regarding bearing lubrication in horizontal process pumps.
The most widely used method is oil sump lubrication.
Oil sump lubrication is one of the oldest and simplest methods of oil lubrication.
The oil sits in the bearing housing at a level approximately ½ way up the bottom dead centre of rolling element.
Oil circulation around the bearing is provided via the bearing rotation agitating the oil sump.
OIL SPLASH LUBRICATION
(Direct contact, Rings or Slinger Discs)
The most common form of bearing lubrication is direct contact.
As the shaft rotates the rolling elements in the bearing, typically steel balls, make contact with a controlled level of oil.
The bearings should not be submerged in the oil more than one-half the diameter of the lowest rolling element or ball.
A constant-level oiler is used to maintain the fluid level in a piece of equipment that naturally depletes fluid through use, wear, friction, misting or evaporation.
The operation is based on the liquid seal principle: as fluid is depleted in the equipment, the liquid seal on the spout inside the constant-level oiler is broken.
When this occurs, air enters into the oil reservoir from the air vent. This releases the fluid from the reservoir and allows it to flow into the equipment until the liquid seal reestablishes itself.
Slinger discs are directly attached to the shaft and are designed to pick-up the oil and splash it throughout the bearing housing.
Flinger rings make contact with the oil and provides splash type lubrication, without direct bearing contact. If the oil level is too high or too low the flinger ring performance is negatively affected
Ring Oil Lubrication
The other name for this type of lubrication is “Ring Oil” lubrication.
The ring oil does not splash the oil to the bearings; it actually lifts the oil from the sump up to the shaft where centrifugal force directs the oil to the rolling element bearings.
A ring oiler is a simple device, consisting of a large metal ring placed around a horizontal shaft, adjacent to a bearing.
An oil sump is underneath this shaft and the ring is large enough to dip into the oil.
As the shaft rotates, the ring is carried round with it. The rotating ring in turn picks up some oil and deposits it onto the shaft, from where it flows sideways and lubricates the bearings.
If the oil level is too high the ring will become submerged reducing its ability to lift the oil onto the rotating shaft, where centrifugal force directs oil to the bearings.
If the level is too low the ring may not be able to pick up enough oil to satisfactorily lubricate the bearings.
Maintaining Proper Level
Maintaining the proper quantity of lubricant is the easiest means of increasing lubrication life and effectiveness.
One of the most widely used methods of maintaining the proper level lubricant in a bearing housing is the constant level oiler.
Constant level oiler.
The constant level oiler replenishes oil lost by leakage through seals, vents and various connections, and plugs in the bearing housing.
Once the proper level has been set, replacing the oil in the reservoir is the only required maintenance.
Constant level oilers have a “control point” that must align with the proper oil level of the equipment.
The oiler is installed on the equipment and oil is filled to the proper level. All constant level oilers require air to function properly.
If the oil level within the sump lowers, the seal at the control point is broken, allowing air to enter the reservoir, displacing the oil until the seal is re-established.
If the constant level oiler is set correctly and there is oil in the reservoir, the equipment will always have the optimum oil level within the sump.
The quality of lubrication is affected by contamination, which is a large contributor to premature bearing failures.
The major types of contaminants are particulate, moisture, incompatible fluids and air entrainment.
Particles in lubricant localize pressure on components causing denting, fatigue, spalling and abrasion to the surface of mating surfaces.
Water will affect the lubricant’s ability to provide a proper fluid film, causing premature failure and excessive wear.
The sources of these contaminants are:
- Generated contamination
- External ingression of contaminants
- Maintenance induced.
Frequently the filler plug on the top of the housing is removed and the oil is introduced to the proper level. This leads to overfilling since much of the oil is still draining from the shaft.
This is commonly the result of incorrect filling, oiler settings, and unrecognized leakage.
The life of a lubricant is significantly reduced when exposed to high operating temperature conditions. The most basic methods to reduce (or maintain) lower oil operating temperatures are:
- Use the correct viscosity oil
- Use quality oil
- Use the right amount of oil
- Keep the oil clean