Purifying Used Oil by "Re-refining"
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nNE considerable item of road%..../tDransport operating costs is lubricating oil, and it seems certain that, under present conditions, this will become an increasing charge. Operators, therefore, will be interested in details of the Petco-Langlois automatic oil " re-refiner "—marketed by the Petroleum Engineering and Trading Co., Ltd., 6, Fitzroy Square, London, W.1—a machine which the maker
asserts reclaims at least 80 per cent. of used oil. This it does not only by filtering the used oil, but also by getting rid of liquid impurities which are in solution and would pass through a filtering medium. Thus diluents, acids, gums, and so forth are removed.
Prior to filtering, the dirty lubricant is mixed with activated earth, supplied by the company. The mixture is introduced into the receiving tank and the earth is kept in suspension by a supply of air pumped through it from the bottom. There is a central tube running vertically upwards from the receiving tank, and the lubricant is drawn into this by vacuum. As it rises it is heated electrically to 450 degrees F.
Having reached the top of the apparatus, the hot mixture enters two filtering chambers, where the earths, sludge and other solids, °together with
acids and gums, are retained. The filtering elements consist of thick, heattreated ceramic plates. There are still certain liquid impurities to be got rid of. These are dealt with in a fractionating chamber, and separate out from the oil as vapour. In this form they are removed by suction to a condenser, from which they can be drained off as necessary.
Centrally situated, that is, below the filtering chambers and above the dirtyoil tank, is the reservoir in which the clean, filtered oil collects. This, of course, is also provided with a drain cock.
Further items of the plant include a device for freeing from acid all gases drawn off, for the protection of the pump ; the vacuum pump, which also injects air into the receiving tank ; two
thermostats; a vacuum gauge and a thermometer.
It is designed to work from mains d.c. or a.c. at any voltage between 110and 250. The plant will be installed on a rental basis, calculated on output, so no capital outlay is involved. There is also a number of depots at which the Petco-Langlois plant is working at which used oil can be purified. Particulars can be obtained from the company at the address given.