It is essential that before introducing the original liquid, the bowl should be filled with water (as near the temperature of the oil as possible). This is called a " Water Seal," and the action of this water seal is to prevent the liquids from both being discharged through the large outlet which would otherwise occur until the bowl became sealed with water. The water seal fills the channels between the top shell and the top disc and between the outer wall of the bowl and the discs. ,

The purifying method is used for : Lubricating oils from steam turbines usually containing water and solid impurities, transformer oils with a high percentage of water present and sludge content, Diesel engine oils containing water and carbon, etc., etc.

B. Clarifying.-This method is to be used when only separating solids from a liquid, or when removing water or some other liquid which is contained in so small quantities that there is no need to discharge it continuously : such solids or moisture thus removed remain then in the sediment space of the bowl.

The clarifier bowl is provided with a single outlet which is through the centre hole of the gravity disc.

The clarifying method is used for instance for varnish.

Oil. To Pour Oil From Drums

To do this without any waste proceed as follows : Tilt the drum on a block of wood, the bung hole being at the highest point, as Fig. 136. The oil will pour out in a stream under perfect control. Use a quart or half-gallon tin, with the top cut open as Fig. 137, to collect the lubricant, from this receptacle it can easily be poured into the tank of a motor car or motor cycle. The drum can be held more steadily if the block of wood is cut away on the edge against which the drum is resting in Fig. 136.

Oil From Grape Seed

Oil extracted from grape seed is stated to equal castor oil in lubricating values, and in grape producing countries has advantages in its lower cost. About 10 per cent, in weight of the oil can be obtained from a given weight of the seed.

Oil Stones

Truing up Oil Stones -These very often become worn, hollow in the centre, due to faulty use, and require making level once more. This is best done by using carborundum powder, say No. 90, dusted on to a cast-iron block, made moist by paraffin, and rubbing down the oil stone, to a level surface on this. Renew the carborundum and paraffin as required, and continue the rubbing down until all hollows disappear. If greater care is taken to use the oil stone all over its surface, rather than in the central part only, it will require very considerably less attention to keep level. It is clearly impossible to get straight level edges on chisels etc., by using an oil stone that is worn into hollows.

Fig. 136.