Patent GB-665994-A (GB)
Title: Improvements relating to the separation of solid impurities from fluids
Inventor: HALSTEAD PHILIP EDWARD
IPC: C10M175/00
Filed: 1948-06-16
Abstract: A process for separating solid impurities from lubricating oil comprises bringing the oil to be treated into contact with a coagulant for particles suspended in the oil and with a further substance which provides a substrate or engulfant for the coagulated particles.  "Engulfant" denotes a liquid substantially immiscible with the oil to be filtered and providing an interface with the oil through which the coagulated particles pass from the oil to the engulfant much more readily than in the other direction, the impurities to be separated being preferentially wetted by the engulfant as compared with the oil to be treated.  The coagulant is preferably a liquid substantially immiscible with the oil and the engulfant more viscous than the oil.  The coagulant may be a nitrogenous base such as aniline, cyclohexylamine, pyridine, dicyclohexylamine, diethylaniline, quinoline, the toluidenes and xylidenes, the hydroxy derivatives of the above compounds and the alkylolamines. Examples of suitable engulfants are the glycols, ethyl cellulose and methyl cellulose (liquid forms, or solid forms in solution) mildly oxidized castor oil and the fatty acid esters of glycerol substantially immiscible with the oil.  Mixtures may be used in each case.  The coagulant and engulfant are preferably used with a support, e.g. a mass of porous filtering material.  A filter cartridge for an I-C engine lubricating oil circulation system may comprise a mass of cotton waste or the like impregnated with pyridine and mildly oxidized castor oil in the proportion of three parts to two by weight.  Alternatively the lubricating oil to be purified may be stirred or otherwise brought into contact with a mixture of the engulfant and coagulant, the impurities from the oil being entrapped in the engulfant which may then be filtered to remove the impurities from it.  Specification 500,433 is referred to.ALSO:Lubricating oil to be filtered is passed through a mass of porous filtering material impregnated with a coagulant for particles suspended in the oil and with a further substance which provides a substrate or engulfant for the coagulated particles.  "Engulfant" denotes a liquid substantially immiscible with the oil to be filtered and providing an interface with the oil through which the coagulated particles pass from the oil to the engulfant much more readily than in the other direction, the impurities to be separated being preferentially wetted by the engulfant as compared with the oil to be filtered. The coagulant is preferably a liquid substantially immiscible with the oil and the engulfant more viscous than the oil.  The coagulant may be a nitrogenous base such as aniline, cyclohexylamine, pyridine, dicyclohexylamine, diethylaniline, quinoline, the toluidenes and xylidenes, the hydroxy derivatives of the above compounds and the alkylolamines.  Examples of suitable engulfants are the glycols, ethyl cellulose and methyl cellulose (liquid forms, or solid forms in solution), mildly-oxidized castor oil and the fatty acid esters of glycerol substantially immiscible with the oil.  Mixtures may be used in each case.  A filter cartridge for an I.C. engine lubricating oil circulation system may comprise a mass of cotton waste or the like impregnated with pyridine and mildly-oxidized castor oil in the proportion of three parts to two by weight.  Specification 500,433 is referred to.