Purpose of Lubrication

Chains need good lubrication for six important reasons  

Lubrication helps prevents wear of the pin-bushing joint. Lubrication cushions impact loads. 

Lubrication flushes away wear debris and other foreign materials. Lubrication smoothes chain to sprocket contact. 

---

The two purposes, of lubricant supply or friction reduction, are of course not entirely distinct, since continuing friction reduction requires a continuing supply of lubricant. The difference lies in the fact that the amount of lubricant required to maintain low friction of the composite itself is relatively small, probably restricted to a film which may be only a few molecules thick. The more general lubrication of a bearing system will require an additional supply of lubricant which is at least sufficient to provide an equivalent film on all the bearing surfaces involved. With the inevitable wastage inherent in movement of lubricant to other surfaces, the lubricant demand will be much greater than for self-lubrication alone. 

Since the lubricant affects bearing life and operation, selecting the proper lubricant is an important design function. The purpose of lubrication in bearing apphcations is to ... 

The purpose of this chapter is to present a special class of compounds, additives, that plays an Important role in the formulation of fuels as well as lubricants. 

The general proportions may be varied from one end of the tower to the other to accommodate changing liquid volumes and physical properties. These towers have been used in diameters ranging from a few inches for laboratory work up to 2.4 m (8 ft) in diameter by 12.2 m (40 ft) tall for purposes of deasphalting petroleum. Other commercial services include furfural extraction of lubricating oils, desulfurization of gasoline, phenol recoveiy from wastewaters, and many others. Columns up to 4.5 m in diameter and up to 50 m in height have been constructed. 

A fuel products refinery with specialties may manufacture products such as lubricating oils, asphalts, greases, solvents, waxes and chemical feed stocks in addition to the primary fuel products. The number and diversity of products will naturally vary from one refinery to another, but for purposes of discussion a fuel products refinery with specialties may include many of the following processes. 

Lubrication. The primary purpose of chain lubrication is to maintain a Film of oil between the bearing surfaces in the joints, thus assuring maximum operating efficiency. This clean oil film must be maintained at all load-carrying points where relative motion occurs, that is, between the pin and bushing on the chain, and the chain and wheel sprocket teeth. Table 3-17 gives some recommended methods for various speeds. 

A thick is deposited on top. This is then covered with a molecularly thin film of lubricant to minimize wear during start-stop contacts and to passivate the disc surface against contamination and corrosion. High-molecular-weight perfluoropolyalkylether (PFPE) polymers are widely used for this purpose. In order to improve surface bonding, the PFPEs are modified with specific functional end groups. All these molecules have similar backbone structures, namely ... 

In order to ensure uniform drawing temperatures and avoid excessive wear on the dies and mandrels used, it is essential that a suitable lubricant be applied during drawing. A wide variety of lubricants are used for this purpose. Heavier draws may require oil-based lubricants, but oil-in-water emulsions are used for many applications. Soap solutions may also be used for some of the lighter draws. Drawing oils are usually recycled until their lubricating properties are exhausted. 

Several of these phosphorus sulfides are produced commercially for industrial applications. P4S3 is one of the key chemical constituents of strike-anywhere matches and has been used industrially for this purpose ever since 1898. P4S10 is the most widely industrially used of the phosphorus sulfides with applications in the preparation of lubricant additives and pesticides and in organic chemistry to convert carbonyl or alcohol groups into their sulfur analogues (see Section 5.4). 

ANTIOXIDANTS. Usually an organic compound added to various types of materials, such as rubber, natural fats and oils, food products, gasoline, and lubricating oils, for the purposes of retarding oxidation and associated deterioration, rancidity, gum formation, reduction in shelf life, etc. 

---