ASTM D4530 test method for determination of carbon residue (Micro method)
6. Apparatus
6.1 Glass Sample Vials, 2-mL capacity, 12-mm outside diameter by approximately 35-mm high.
6.2 Larger 4 dram Glass Sample Vials, 15-mL capacity (20.5 to 21-mm outside diameter by 70 more or less 1-mm high), may be used for samples that are expected to yield residues <0.10 % (m/m) so that a more appreciable mass difference can be determined. It should be noted the precision statements for the test method were determined using the 2-mL capacity vials only (with sample residues between 0.3 and 26 % (m/m) and that the precision associated with using the larger sample vials has not been determined.
6.3 Eyedropper, Syringe, or Small Rod, for sample transfer.
6.4 Coking Oven8 with circular heating chamber approximately 85 mm (3 3/8 in.) in diameter by 100-mm (4-in.) deep, for top loading, with heating capability from 10 to 40°C/min rate to 500°C, with exhaust port 13-mm (1/2-in.) inside diameter for nitrogen purge of oven chamber (inlet near top, exhaust at bottom center) with thermocouple sensor located in oven chamber next to but not touching sample vials, with lid capable of sealing out air, and with removable condensate trap located at the oven chamber base. A schematic diagram is given in Fig. 2.
6.5 Sample Vial Holder - Cylindrical aluminum block, approximately 76 mm (3 in.) in diameter by 16-mm (5/8-in.) thick, with twelve evenly spaced holes (for vials) each 13 mm (1/2 in.) in diameter by 13-mm (1/2-in.) deep. The holes are arranged in a circular pattern approximately 3 mm (1/8 in.) from the perimeter. The holder has legs 6-mm (1/4-in.) long, with guides to center in oven chamber, and an index mark on the side to use as position reference. The sample vial holder is shown in Fig. 1.
6.6 A modified version of the standard sample vial holder (see Fig. 1) is required when larger glass sample vials (see 6.2) are used. The modified sample vial holder is similar in nature to the twelve hole vial holder, except that there are six evenly spaced holes (for vials) each 21.2 more or less 0.1 mm in diameter by approximately 16-mm deep, arranged in a circular pattern.
6.7 Thermocouple, suitable for controller and temperature range of interest, with exterior temperature readout, degrees Celsius.
6.8 Analytical Balance, with more or less 0.1 mg sensitivity to 20 g minimum weighing capacity.
6.9 Nitrogen, minimum 99.998 % purity with suitable means of delivering a pressure of 0 to 200 kPa (0 to 30 psig). Cylinders of zero grade nitrogen have been found suitable to use.
7. Sampling
7.1 Using the practices outlined in Practice D4057 (manual sampling) or Practice D4177 (automatic sampling), ensure that a representative sample of material to be tested is obtained.
