EXTRACTING OIL

Nelson Evening Mail, Volume LXI, 29 December 1926, Page 9

EXTRACTING OIL

ONE OF THE WORLD'S OLDEST

INDUSTRIES - From the earliest times oils and fats have served mankind as one> of/jbhe most important articles of food, so that the' methods of their preparation and production must form one of the oldest industries in the world. These methods consist of three main groups. Extraction of oil by boiling out with water; by expression; and by means of solvents. The first method only requires the simplest machinery, and can only be applied with success to those seeds which contain large quantities of fatty matter, such as cocoa-nuts and olives and palm fruit. It is the method of extraction by expression which has taxed the ingenuity of engineers to the uttermost, and it is interesting to trace the evolution pf modern oil mill machinery through the ages. _ The earliest method of pressing con-sisted-of packing olives into a sack and piling stones upon them. Then the Greeks and Romans used a simple screw "bress, but it was the Chinese who, at a very early stage of history, actually employed the same series of operations which are followed in the most advanced oil mills to-day. This consisted of bruising and reducing the seeds to meal under an edgestone, heating the metal in an open pan and pressing out the oil 'in a wedge press in which the wedges were driven home bv hammers.

The stamper press,' invented in Holland in the seventeenth century, marked the next milestone, and until the beginning of the nineteenthicentury was used almost exclusively in Europe for pressing oi! seeds. It consisted of two principal parts, an oblong rectangular box with an arrangement of plates, blocks and wedges, and over it a framework with heavy stampers which, by their fall, produced the l ' pressure.

In 1795, however. the invention of the hydraulic press brought about a revolution in the oil producing industry, and from that time onwards British machinery! has been supreme. Preliminary purification of seeds and nuts is of the greatest importance, and* in the case of seeds among which pieces of iron are found, the seeds are passed over magnetic separators. They are then husked, if necessary, and what is known as the "meals" are ground by passing through rollers consisting of*m"etal cylinders which are sometimes grooved so that the seed- is cut up and ground while passing between. The resulting meal is then either expressed in this state or subjected to a preliminary heating according to its nature. By pressing i,n the cold, of course, only part of the oil is recovered. A very wide range of machinery has now been perfected to obtain the best results from the numerous seeds t and nuts having a commercial value.

A modem Anglo-American mill for linseed and similar small seeds which do not contain a high percentage of oil will consist of a group of machines forming one unit. Crushing rolls; cooking kettle; cake moulding machine; set of hydraulic presses; cake paring machine; pumps and the necessary seed elevators, valves, pipes and driving gear. When two or more units are combined, hydraulic accumulators to store and regulate the pressure should be used. A British company, has equipped some o? the, largest, oil mills in tho world, and can supply complete plants of machinery for dealing with any oil bearing seed up to any capacity.