Pour the sample, heated in a water bath if necessary, into the jar to a height of 51 to 57 mm. Close the jar with the cork-carrying thermometer No.1 so that the thermometer bulb is immersed vertically in the sample with the beginning of the capillary 3 mm below the surface. Heat the sample, without stirring, to a temperature of 46*C in a bath maintained at a temperature not higher than 48*C Cool in the sample to 32*C in air or in a water bath at approximately 25*C. If a pour point below minus 35*C is expected, cool the sample in air or in water bath to 16*C and replace the thermometer No.1 by thermometer No.2 Fit the gasket on to the jar 25 MM from the bottom and insert the jar into the jacket. The disc, the gasket, and the jacket shall be kept clean and dry.
If a pour point above 32*C is expected, heat the sample to 46*C or to a temperature 8*C above the expected pour point, and fit the jar into the jacket immediately. One the sample has cooled enough to allow the formation of wax crystals, take great care not to disturb the mass of sample nor to permit the thermometer to shift in the sample. Any disturbance of the spongy network of crystals will lead to false results. Maintain the bath temperature at minus 1*C to plus 2*C. Support the jacket and jar in a vertical position in the bath so that not more than 25 mm projects form the cooling medium. Beginning at a temperature 12*C above the expected pour point, at each thermometer reading which is a multiple of 3*C, remove the jar from the jacket carefully, and tilt it just enough to see whether the oil will move and the replace it, this complete operation shall not take more than 3 seconds.If the oil has not ceased to flow when it has been cooled to 9*C, place the jar and jacket in another bath maintained at a temperature of minus 32*C to minus 35*C. If the pour point is very low, maintain additional baths with successively lower temperature differentials of about 18*C, transfer in the jar and jacket when the temperature of the sample reaches a point 27*C above the temperature of the new bath. As soon as the sample ceases to flow when the jar is tilted, hold the jar in horizontal position for exactly 5 seconds. If the sample shows any movement replace the jar in the jacket and cool down the sample another 3*C. If the oil shows no movement during the 5 second, record the reading of the thermometer.
Certain lubricating oils tend to move as a whole. The point at which they cease to flow is consequently more difficult to detect. For black oil, cylinder stock, and non-distillate fuel the result obtained by the procedure described in 9.1 and 9.2 is the upper (maximum) pour point. Determine the lower (Minimum) Pour Point by heating the sample with stirring to 105*C, pouring it into the jar, cooling it to 32*C as before.Calculation and Reporting :
Add 3*C to the temperature recorded above and corrected for thermometer errors if necessary, and report the result as the pour point. For black oil, cylinder stock etc report both the upper and lower pour point.Precision:
Results of Duplicate tests shall not differ by more than the following amounts.