Types of lubrication

• Label the following 'Action of journal bearing' diagram?


  A ) Load on shaft

  B ) Region of low pressure (place to feed oil)

  C ) Shaft

  D ) Bearing

  E ) Region of high pressure

  F ) Oil film

  G ) Supporting pressure of bearing

  
• Hydrodynamic lubrication means that the load carrying surfaces of a bearing are separated by a relatively thick film of lubricant to prevent a metal to metal contact.
• Hydrodynamic lubrication means that the load carrying surfaces of a bearing are separated by a relatively thick film of lubricant to prevent a metal to metal contact.
• Hydrodynamic lubrication does not depend on the application of the lubricant under pressure.
• Hydrodynamic lubrication does not depend on the application of the lubricant under pressure.
• The main feature of Hydrodynamic lubrication, is to provide a sufficient quantity of lubricant at all times.
• The main feature of Hydrodynamic lubrication, is to provide a sufficient quantity of lubricant at all times.
• Disadvantages of Hydrodynamic lubrication:

  • The oil can leak from the bearing when the shaft is not rotating.
  • Thus, causing metal to metal contact which could damage the bearing.
• Disadvantages of Hydrodynamic lubrication:

  • The oil can leak from the bearing when the shaft is not rotating.
  • Thus, causing metal to metal contact which could damage the bearing.
• Hydrostatic lubrication is when the pressure of the lubricant builds up as a result of an external source, such as an oil pump, supplying the pressure.
• Hydrostatic lubrication is when the pressure of the lubricant builds up as a result of an external source, such as an oil pump, supplying the pressure.
• Classes of lubricants:

  • Solid
  • Semi-solid
  • Liquid
• Types of solid lubricant:

  • Graphite
  • White lead
  • Talc
  • Soapstone
  • Mica
• Types of solid lubricant:

  • Graphite
  • White lead
  • Talc
  • Soapstone
  • Mica
• Graphite is the most widely used solid lubricant, because it is not affected by acid or heat.
• Graphite is the most widely used solid lubricant, because it is not affected by acid or heat.
• Solid lubricants are used in bearings or such parts of machinery which are prone to be neglected from a lubricating point of view and particularly those which operate at low pressures and low speeds.
• Solid lubricants are used in bearings or such parts of machinery which are prone to be neglected from a lubricating point of view and particularly those which operate at low pressures and low speeds.
• Solid lubricants are used in:

  • Bearings that operate at low pressures and low speeds.
  • Parts of machinery which are prone to be neglected from a lubricating point of view.
• Solid lubricants are used in:

  • Bearings that operate at low pressures and low speeds.
  • Parts of machinery which are prone to be neglected from a lubricating point of view.
• Grease should only be used in special conditions, such as in cement mills or collieries, where there is dust and dirt.
• Grease should only be used in special conditions, such as in cement mills or collieries, where there is dust and dirt.
• Semi-solid lubricants are used where spattering or leakage is undesirable, such as in food or sweet factories.
• Semi-solid lubricants are used where spattering or leakage is undesirable, such as in food or sweet factories.
• Grease is the most widely used Semi-solid lubricant.
• Grease is the most widely used Semi-solid lubricant.
• Semi-solid lubricants are used on slow running bearings under heavy loads.
• Semi-solid lubricants are used on slow running bearings under heavy loads.
• Rough, heavy machinery is generally lubricated with grease.
• Rough, heavy machinery is generally lubricated with grease.
• Oil is the most widely used Liquid lubricant.
• Oil is the most widely used Liquid lubricant.
• Types of oils:

  • Animal oils
  • Vegetable oils
  • Mineral oils
• Examples of Animal oils:

  • Lard
  • Sperm oil
  • Tallow
• Examples of Animal oils:

  • Lard
  • Sperm oil
  • Tallow
• Examples of Vegetable oils:

  • Castor oil
  • Palm oil
  • Olive oil
  • Linseed oil
• Examples of Vegetable oils:

  • Castor oil
  • Palm oil
  • Olive oil
  • Linseed oil
• Mineral oils retain their properties well in air and, if they are pure, do not gum or dry up.
• Mineral oils retain their properties well in air and, if they are pure, do not gum or dry up.
• A thin, light, liquid lubricant such as oil is used mainly for high speeds and light loads.