High-Temperature Grease Guide Private2 months ago - Real estate - Bāli - 29 views
There are many criteria to consider when selecting a high temperature grease for hot, grease-lubricated equipment.
The selection must include consideration of oil type and viscosity, oil viscosity index, thickener type, stability of the composition formed by the oil and the thickener), additive composition and properties, ambient temperature, operating temperature, atmospheric contamination, loading, speed, relubrication intervals, etc.
A reasonable starting point for selecting a high temperature grease is to consider the nature of the temperatures and the causes of product degradation. Greases could be divided by temperatures along the lines in Table 1.
There is general correlation between a grease’s useful temperature range and the expected price per pound. For instance, a fluorinated hydrocarbon-based (type of synthetic oil) grease may work effectively as high as 570oF (300oC) in space applications but may also cost hundreds of dollars per pound.
To maximize grease lubrication effectiveness, minimize cost and minimize risk of application-induced failure, lubricant manufacturers have made an effort to formulate greases that cover a variety of applications. These greases range from slow to high speeds, and from low to high loads, in an effort to provide a single product to meet a multitude of requirements. The result is general purpose grease.
What is General Purpose Grease?
Equipment Properties to Consider
Given the wide range of characteristics that may exist in the greases at any given plant, it is best to first characterize the equipment and plant conditions, then select a general purpose grease to meet the conditions.
As the load increases, the grease’s base oil viscosity must also increase to support the load. If the majority of the components in the mill/plant environment are heavily loaded, it may make sense to use high-viscosity base oils for a general purpose product. This might be the case in a cement, steel or paper mill environment. It is not uncommon to find GP greases made from 460 cSt (40°C) and heavier oils in these types of environments.