ASTM D6426 method for determining fiterability of middle distillate fuel oils
9. Procedure
9.1 Measure the temperature (see 6.3.3) of the fuel in the transfer container (see 7.2), and if necessary, adjust to 15 to 25°C.
9.2 Rinse the fuel reservoir container (see 6.1.1.4) with some of the product to be tested.
9.3 Shake the transfer container (see 7.2) vigorously for approximately 2 min.
9.4 Place 450 +/- 5 mL of the sample into the fuel reservoir (see 6.1.1.4). Check that the temperature is still within the range from 15 to 25°C. Record the actual temperature. If any undissolved water is visually apparent in the fuel at this time, as determined by Test Method D4176 or D4860, or both, the test shall be abandoned and the presence of water shall be reported.
9.5 Place the end of the Tygon tubing with the Luer-Loc coupler (see 6.1.1.9) into the collection container (see 6.1.1.5).
9.6 Press and release the PURGE pushbutton. Approximately 40 mL will be drawn from the fuel reservoir through the Tygon tubing and discharged into the collection container, thus purging the air and any residual fuel from the system. The fuel flow will automatically cease at the end of the purge cycle (2 min).
9.7 After the purge cycle, insert the Luer-Loc coupler affixed to the Tygon tubing into a precalibrated FCell filter (see 6.2) and place the filter into the mouth of the collection container.
9.8 Press and release the TEST pushbutton. The peristaltic pump activates, drawing the fuel from the fuel reservoir, extruding it through the filter into the collection flask.
9.9 During the filtration period, the pressure is constantly displayed along with the amount of sample processed. The test will automatically stop when one of the following occurs:
9.9.1 The entire sample (300 mL) is discharged prior to reaching 104 kPa (15 psi). The total volume V(V=300 mL), the final pressure, P(FP<15 psi @ 300 mL), and F-QF will be displayed.
9.9.2 The entire sample (300 mL) has not been discharged, and the maximum allowable pressure 104 kPa (15 psi) has been reached. The volume, V(V at 15 psi), discharged at 104 kPa (15 psi), the final pressure, P(FP=25 psi), and the F-QF will be displayed.
9.10 At the completion of the test, unclamp the Tygon tubing from the pump to relieve the back pressure; disconnect the FCell filter; place the end of the Tygon tubing that was attached to the FCell filter into the collection container (6.1.1.6). Drain all of the remaining fuel from the fuel reservoir container (6.1.1.5) and from all of the tubing including the section connected to the pressure transducer into the collection container.
