Patent GB-785936-A (GB)
Title: Improvements in or relating to incorporation of solid materials in oil
IPC: B01F3/12
Filed: 1954-12-23
Abstract: A suspensionof a solid material in lubricating oil is prepared by mixing relatively coarse particles of the solid material with a vaporizable liquid, passing the resulting mixture into a heating zone to vaporize the liquid and form a dispersionof the solid particles in vapours flowing at high velocity, subjecting the highvelocity dispersion to conditions of turbulence sufficient to reduce the solid particles to fine particles of greatly reduced size and blending the fine particles with lubricating oil.  Solid materials mentioned are silica, alumina, magnesia, calcium or magnesium hydroxides, ferrous or ferric oxides and hydroxides, vanadium oxide, silicates of magnesium, calcium and aluminium, calcium sulphate, calcium carbonate, calcium phosphate, clay and forms of carbo such as graphite and carbon black.  The vaporizable liquid may be water or lubricating oil and, if it is the latter, the high-velocity dispersion containing the fine particles may be cooled to condense the oil vapours and the fine particles may be blended with the resulting oil condensate.  If the solid material is a gelling agent, the fine particles of this material may be blended with the lubricating oil in such a proportion as to yield a lubricating grease.  If desired, however, part or all of the gelling effect may be produced by the addition of soap or soap-forming materials (e.g. aluminium hydroxide and stearic acid) at some stage during the preparation of the grease.  Soaps mentioned are the metal (e.g. aluminium, lead, lithium, copper, cobalt, nickel, cadmium, mercury, strontium, zinc, sodium or iron) salts of fatty acids (e.g. oleic, palmitic, myristic, arachidic, stearic or behenic acid), hydroxy fatty acids (e.g. hydroxy stearic acid), naphthenic acids or rosin acids, and in particular aluminium stearate and lead or lithium 12-hydroxystearate.  A gelling effect may also be produced by the addition of metal sulphonates.  Lubricating oils mentioned are mineral oils, water-soluble monoalkyl ethers of oxyethyleneoxy-1,2-propylene copolymers, alcohols and esters. Additional ingredients may be incorporated in the lubricating oil compositions, for example, corrosion inhibitors, oxidation inhibitors, viscosity index improvers (e.g. polymerized, olefins), asbestos, mica, talc, antimony sulphide, metal powders (e.g. aluminium, lead, zinc or copper), borax, barium sulphate, tricresyl phosphate, sodium metaphosphate and materials for improving the oil-wettability of the solid particles (e.g. alkali and alkaline earth metal petroleum sulphonates, and iron or lead sulphides formed in situ by the action of hydrogen sulphide on iron or lead salts such as the chloride or nitrate).  Apparatus for carrying out the process of the invention is described (see Group II).  In the examples, the process is employed to prepare mineral lubricating oil compositions (which, in some instances, are greases) containing graphite (with or without sodium or aluminium stearate) or silica (with or without sodium stearate).  Specification 683,318, [Group II], is referred to.