6.6 Coalescing bed-type oily water separators The coalesce is capable of forming oil globules up to l2 mm diameter and the heavier fuel oils usually form long 'stalagmites' which grow to a considerable size before they are released. Because of the 1ow velocities employed the collected oil can flow past the water screen without becoming re-entrained and carried through into the outlet

6.5 Cleaning the Comyn oil/water Separater To clean out the separator ensure that all oil possible has been drawn off through the oil recovery valve and scum valve, and that the separator is full of water. Turn on steam to heating coil; also steaming out connection, and allow the separator to become thoroughly hot

General Operating Procedure Before pumping oily water into the separator it is important that the separator is completely filled with clean water, either direct from the sea or through the filling valve provided for this purpose. It is essential to keep the lower internal surfaces and outer chamber from becoming coated with oil

Principle The rising velocity of the globules carries them upwards where they become trapped by the under-surfaces of the plates and coalesce until the enlarged globules have sufficient rising velocity to travel along the plate surface and break away at the periphery

4.1 Function The purpose of the operation is either to liberate a liquid from strange particles, or to separate two intermixed liquids

6.2 Pumping considerations Since the rate of separation depends on the oil globule size it will be appreciated that any disintegration of oil globules in the oily feed to the separator should be avoided and this factor can be seriously affected by the type and rating of the pump used. Tests were carried out by a British government research establishment some years ago on the suitability of various pumps for separator feed duties (Double vane, Triple screw and Single vane )

The principle of separation by which all commercially available oil/Water separators is the gravity differential between oil and water. In oily water mixtures, the oil exists as a collection of almost spherical globules of various sizes. The force acting on such a globule causing it to move in the water is proportional to the difference in weight between the oil particle and a particle of water of equal volume. This can be expressed as:

5.2 Operation Safety regulations In all centrifugal separators the bowl rotates at a very high speed, normally between 100 and l50 revolutions per second. Thus, very great forces are released and it is essential, therefore, to follow strictly the directions given in the Instruction Book concerning assembly of parts, starting, stopping and overhaul

Cleaning, overhaul, lubrication. Satisfactory functioning cannot be ensured unless the parts in contact with liquid are carefully cleaned before assembly. This applies particularly to seal rings, sliding surfaces, guiding and contact surfaces, and threads. Also take care that no burrs are knocked up on the metal parts when handling them. Follow the directions given in chapter 5.4 and 4.5

To ensure good combustion in diesel engines and reduce wear and corrosion in this type of engine it may be necessary to remove certain impurities from fuel and lubricating oils. These include ash, various salts and water present in fuel oil and carbonaceous matter, metals, acids and water present in used lubricating oil. carbonaceous