Determine cloud and pour point of given sample of oil.

Determine cloud and pour point of given sample of oil.

THEORY: -

1. CLOUD POINT:-

It is the temperature in a standardized test at which cloudiness develops due to separation of wax. At this temperature solid matter begins to crystallize out and separate out. The cloud point occurs at higher temperature than the pour point.

2. POUR POINT:-

It is the temperature at which the oil will stop to flow then cooled under specified conditions.

Lubricating oils which are mixture of various hydro carbons, behave like a portion of their constituents before the whole mixture solidifies upon cooling. The setting point of oil will therefore temperature at which solid matter commences to separate or the temperature at which the oil completely loses its fluidity. Oil containing paraffin’s temperature at which separation of solid paraffin is observed to commence is recorded as cloud point for mineral oil which contain no paraffin’s the separation can not be seen up on cooling of this oil. The temperature, just above the temperature at which flow of oil cease is recorded as pour point.

Experimental Set Up:

The test jar shall be of clear glass, cylindrical form and flat bottom. The cork C shall be fit the test jar and shall be of bored centrally to take the test thermometer B. The jacket D shall be of glass or metal shall be water tight of cylindrical form, flat bottom with inside diameter greater than the out side diameter of the test jar. A disk of cork or felt and of same diameter as the inside diameter of jacket is required. The ring gasket F male fit snugly around the out side of the test jar and loosely inside the jacket.

This gasket may be made of Cork flit or other suitable material, elastic enough to cling to the test jar and hard enough to hold is shape. The cooling bath G shall be of a type suitable for obtaining the required temperature. A suitable support for holding temperature is required. A support suitable for holding the jacket firmly in a vertical position is also provided in the bath. The required bath temperature is obtained by suitable freezing mixture or refrigeration.

METHOD OF TEST:-

1. Cloud point:-

The oil to be tested shall be brought to a temperature at least 25 F above the approximate cloud point moisture if present shall be removed by any suitable method as by filtration through Plaster of Paris or dry filler filter of paper to a temperature of 15 F higher then its pour point the oil shall then be poured in to the test jar A to a height of not less

than 5 cm not more than 5.5 cm. The test jar may be marked to indicate the proper level. The test jar shall be tightly closed by Cork C carrying a Thermometer bald immersed. So the beginning of the capillary shall be 3 mm below the surface of the oil. The disk E shall be placed in the bottom of jacket D and the test jar with the ring gasket F 2.5 cm above the bottom shall be inserted in to the jacket.

The disk gasket and inside of jacket shall be clean and dry. After the oil has cooled enough to allow the formation of paraffin wax crystals, great care should be taken neither to disturb the mass of the oil nor to permit the thermometer to shift in the oil. The temperature of cooling bath G should be adjusted so that is F not more than 30 P and this temperature should be maintained throughout the test.

At each test thermometer reading which is multiple of 5 F. the test jar should be removed & tilted to as certain whether the oil around thermometer flows when the jar shall be replaced in the jacket.

As soon as the oil around the thermometer does not flow when the jar is tilted the test jar is held in a horizontal position for exactly five seconds and observes carefully. If the oil around the thermometer until the oil is perfectly clear. But such filtration shall be made at a temperature at least 25 F above the approximate cloud point. The clear oil shall be poured in to the test jar A to a height of not less then 25 cm not more than 3 cm. the test jar may be marked to indicate the proper level.

The cork C carrying a thermometer bald immersed. So the beginning of the capillary should be 3 mm below the surface of the oil. The disk E shall be placed in the bottom of jacket D and the test jar with the ring gasket F 2.5 cm above the bottom shall be inserted in to the jacket. The disk gasket and in bottom the temperature of cooling bath G shall be adjusted. So that it is below the cloud point of the oil by not less than 15 F nor more than 30F and this temperature shall be supported firmly in a vertical position in the cooling bath so that not mark than 25 cm of the jacket projects out of the cooling medium. At each test thermometer reading which is multiple of 2 F the test, jar shall be removed from the jacket quickly but without disturbing the oil inspected for cloud and returned to the jacket when such inspection first reveals a distinct cloudiness is the oil at the bottom of the test jar it is recorded as the cloud point.

2. Pour point:-

The oil to be tested shall be brought shows any movement under these conditions. The jar shall be immediately replaced in the jacket and the same procedure shall be repeated at the next temperature. Reading 5 F lower in determining the pour point, it shall be noted that the first movement of the oil in certain cases is not around the thermometer but from the sides of movements shall be considered in marking the test.

As soon as a temperature is reached at which the oil around the manometer shows no movement when the test jar is held in a horizontal position for exactly five seconds and the test shall be stopped. The lowest reading of the thermometer shows any movement when the jar is held in vertical position for five seconds shall be noted that the pour point is the temperature 50 F above the solid point or temperature, at which the test is discontinued.