New Features in a Range of Oil Reclaimers Additions to the Metafilter Range Include a New Pumpoperated Apparatus
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IN our issue dated February 14 last
we described a new method of oil filtration developed by Metafiltration Co., Ltd., Belgrave Works, Hounslow, Middlesex, in which the filtering medium consisted of specially prepared paper • discs. Since that time the results obtained have proved so satisfactory that the concern is now marketing a range of reclaiming apparatus.
• Six models; are available, five of them being operated by compressed air, whilst one model is of the pumpoperated type.
The compressed-air type comprises a base tank for the used oil, on top of which is a casing containing the filter element. Air pressure is applied up to 120 lb. per sq. in., which forces the oil from the base tank to the filter element, through which it passes to a clean-oil container. A 100-150-watt heater is built into the casing containing the filter element ; this raises the tempera; ture of the oil to about 90 degrees C., and, by reducing the viscosity, increases the speed of filtration.
Operation without Attention.
Features of the plant include a safety device to prevent the head of the filter compartment from being removed when the air pressure supply is on. Furthermore, in view of the fact that the apparatus must be left unattended for long periods, the electric heater is designed so that it can be left on indefinitely without fear of damage.
The Metafihre pockets were fully described in our issue dated February 14. It has been demonstrated that the filter units, which are made up of a number of these pockets, are capable of extracting all traces of suspended impurities, including even colloidal carbon. Filter pockets cost 6s. per 100. The cost of reclaiming the oil works out at a maximum of 3d. per gallon, if the condition of the oil necessitates new pockets every 24 hours.
The prices of the compressed-air units are :—One gallon per day size ,(10 pockets), £12; 5 gallons (25),
£35; 10 gallons (50), £45; 15 gallons (75), £55; and 20 gallons (100), £70.
An accompanying illustration shows the new pump-operated apparatus, which is designed to remove volatile matter in addition to suspended impurities, and advantage is again taken of the efficient Metafibre pockets.
The dirty oil is poured into the header tank through a rough strainer, and is taken from the tank by a float take-off, which skims the oil before it flows through a thermostatically controlled valve to the base of the condenser. A one-kilowatt heater is incorporated in the condenSer and the oil flows over the top of the heater, at a temperature of about 140 degrees C., passing down in a thin, film to a base chamber. During this period volatile matter and moisture are • removed, and a carefully designed evaporatof allows the vapour to rise to the top of the flue, where it is condensed and drained off.
A thermostat in the condenser controls not only the temperature of the heater, but also the valve in the flow pipe. If the header tank becomes empty the thermostat cuts off the heat.
Moisture and volatile matter having been removed, the hot oil in the chamber at the base of the filter is ready for further filtering to extract solid suspended impurities. To attain this end a worm-driven piston-type pump is operated by an electric motor. This pump delivers the oil direct to the filter body, which contains 50 pockets.
Dirty Oil Pre-heated.
-A relief valve is incorporated in the filter body and it is arranged to blow off at a pressure of 100 lb. per sq. in. The oil passed through the relief valve returns to the dirty-oil tank. As in practice this pressure is quickly attained, the filter operates continuously, with the relief valve in action. The hot oil thus released helps in preheating the dirty oil.
The motor for driving the pump consumes little current and, whilst the heater has a capacity of one kilowatt, it is automatically cut out of action during a good proportion of the time.
The capacity of the outfit is 15-20 gallons per day of really bad oil, but where the used oil is in fair condition, as many as 40 gallons have been filtered in a day.
The efficiency of this unit was demonstrated to us when we inspected a filter unit which had extracted no less than 2 lb. of solid matter from 1/ gallon of the worst class of lubricant taken from an oil engine.
The pump-operated unit, as described, costs £45, complete with 20filter elements.