6.Differences between Oil and Grease Lubrication Systems

Lubrication System Type

Oil Lubrication System

Grease Lubrication System

Lubricant Properties

• Oils have relatively low viscosity, high fluidity, and low oil-film adhesion.
• Oils are suitable for intense friction, high-speed, and high-temperature applications.
  

• Greases have relatively high viscosity, low fluidity, and high oil-film adhesion.
• Greases is suitable for components that endure heavy loads.
  

Lubricator Operating Pressure

The operating pressure of an oil lubricator is relatively low, generally under 30kgf/cm².

The operating pressure of a grease lubricator is relatively high, generally above 100kgf/cm² , and can reach as high as 300kgf/cm².

Lubricator Design

Due to the oil's properties, the oil tank is at the bottom of the lubricator. Oil is refilled from the top oil filler inlet of the oil tank.

Due to the grease's properties, the grease tank is on top of the lubricator. Grease is refilled from the grease inlet at the bottom of the grease tank by a grease gun.

In most general grease lubricators, the grease tanks have grease-follower plates to push the grease downwards. Other types, such as high-pressure stirrer type and disposable grease lubricators, are also available in the market.

Application

With the low technical threshold, initial startup cost, easy acquisition, and simple operation, many oil lubricators with a wide range of applications are available in the market.

The general viscosity of the grease used in the lubrication system is between NLGI 000 and 2. According to the grease's viscosity, the lubricator's drive capacity and selection of the lubricator model will be different. Furthermore, the grease lubricator's design requires the ability to endure high operating pressure, along with its accessories, such as distributors and oil pipes. The technical threshold of a grease lubrication system is much higher than the oil one.