ASTM D20 Standard Test Method for Distillation of Road Tars
6. Preparation of Sample
6.1 Thoroughly stir or otherwise mix the sample immediately before removing the portion for testing, to ensure that such portion will be representative of the sample. If warming is necessary, take care to avoid loss of volatile material.
7. Preparation of Apparatus
7.1 Assemble the apparatus as follows (see Fig. 2 and Fig. 3):
7.1.1 Suspend the burner chimney by its flange from the support ring, place the specified two sheets of flat wire gauze on the burner chimney, and place the flask shield on the upper sheet of gauze. In case the electric heater is used, attach the heater to a vertical support so that at the end of the distillation it can be lowered at least 150 mm. Place the upper refractory on the heater with the larger opening facing upwards. Set the flask shield on the upper refractory.
7.1.2 Inset the thermometer through a new and rolled select quality regular-length cork of suitable size. Position the thermometer and cork in the neck of the flask so that the cork fits tightly and the bottom of the cork is from 23 to 28 mm above the lowest point of the junction between the side-arm and the neck of the flask. Then adjust the thermometer in the cork so that the top of the bulb is level with the lowest point of the juncture between the side-arm and the neck of the flask. Align the stem of the thermometer on the axis of the bulb through the neck of the flask.
7.1.3 When using the flame distillation apparatus, place the flask in the flask shield with its bulb resting on the gauze. Position the burner so that it is directly beneath the point where the bulb of the flask contacts the gauze. If the electric heater is used, place the flask in the flask shield and support the flask so that its bottom is between 4 and 7 mm above the heating coils.
7.1.4 Connect the condenser tube to the side-arm of the flask with a tight cork joint, having the side-arm project 30 to 50 mm through the cork. The distance from the neck of the flask to the outlet end of the condenser tube shall be between 500 and 600 mm. Support the condenser tube in a position such that it is in alignment with the side-arm of the flask, and the thermometer is vertical. Place the shield cover over the flask shield around the neck of the flask.
