ASTM D3117 Test Method for Wax Appearance Point of Distillate Fuels
6. Apparatus
6.1 Specimen Tube - A double-walled (Dewar-type) jacketed tube with dimensions shown in Fig. 1.
6.2 Temperature Measuring Device - Liquid-in-glass thermometer conforming to specifications for ASTM Thermometer 62C in accordance with Specification E 1, or any other temperature measuring device with equal or better accuracy and equal temperature response.
6.3 Stirrer Assembly - A stainless steel wire configured in the manner described in Fig. 2 and manipulated by a motor or other suitable device in a vertical direction. The frequency of movement shall be 55 more or less 5 cycles/min with an amplitude of 50 more or less 5 mm. The stirrer shall be concentric with the temperature measuring device and shall be fitted with the moisture proof collar specified in Test Method D2386. A No. 3, two-hole neoprene rubber stopper shall be used to seal the top of the specimen tube.
6.4 Cooling Bath - Use an unsilvered vacuum flask having minimum dimensions of 200-mm depth and 65-mm internal diameter. The bath temperature, below -45°C, may be maintained by refrigeration or suitable freezing mixtures (7.1). Bath temperature is monitored with an appropriate temperature measuring device such as ASTM Thermometer 6C.
NOTE 1 - Solid carbon dioxide chips (dry ice) and isopropanol is a recommended mixture for coolant. An excess of dry ice should be avoided to prevent obscuring the sample tube in a continuous stream of bubbles. Isopropanol should be replaced daily or when low temperature viscosity is noticeably higher than a fresh bath. Liquid nitrogen may also be used as coolant instead of liquids cooled with solid carbon dioxide.
6.5 Illumination - A 150 to 230-mm long, 5 to 8-W fluorescent tube shall be mounted behind the specimen to illuminate it with transmitted light. Observations shall be made with the sample tube between the observer’s eye and the lamp.
6.6 Clock - Use a clock or other timing device readable to 10 s to monitor the cooling rate.
7. Materials
7.1 Carbon Dioxide (Solid) or Dry Ice - (Warning - Extremely cold, -78°C.) A commercial grade of dry ice is suitable for use in the cooling bath (Note 2).
7.2 Isopropanol or Isopropyl Alcohol - (Warning - Extremely flammable.) A commercial or technical grade of isopropanol is suitable for the cooling bath.
7.3 Liquid Nitrogen - (Warning - Extremely cold, -196°C.) A commercial or technical grade of liquid nitrogen is suitable for the cooling bath. See Note 2. (Warning - Carbon dioxide (solid) and liquid nitrogen liberate gases that can cause suffocation. Contact with skin causes burns, freezing, or both.)
