Advantages with grease lubricate opposite to oil lubrications:
Greases resist leakage, drop and throq off. Greases from a protective skin which prevents the ingress of water and particular contamination. Greases maintain their structure under high load. disadvantages are that greases provide no cooing and have higher friction properties than oil. Greases consist of between 75% and 95% lubricating oil, the remainder consisting of additives and thickening agents. The thickening agents provide a 3 dimensional structure, whitin which the lubricating oil is held. The additives improve properties such as operating life, wear, corrosion, and abrasion resistance.
Grease with thickening agents are in 3 type differences:
Grease with Lime Complex |
Resistant against water |
Up to 50°C |
Grease with Sodium Complex |
Not resistant against water |
Up to 90°C |
Grease with Lithium Complex |
Resistant against water i |
Up to 140°C |
Don't mix greases with different constitutes and different viscosities together.
PENETRATION, NLGI CLASSES :
The flow characteristics of oils and greases are defined by their viscosities. The viscosity is established by the use of a cone penetrometer. The further into the grease that the cone penetrates, the lower the viscosity. Penetration is mesured in 1/10mm. The number of 1/10mm of penetration defines the viscosity and from this number, greases are classified according to the NLGI classification system.
Care should be taken using grease under low temperature with different viscosities. |
