ASTM D6824 Standard Test Method for Determining Filterability of Aviation Turbine Fuel
7. Sampling
7.1 The fuel sample from which an aliquot is being drawn for the purposes of this test method shall be representative of the lot of fuel. Obtain the sample in accordance with the procedures of Practices D4057 or D4177, and report (see 10.1) how and from where it was obtained. The maximum sample size is dictated by the quantity that can be mixed thoroughly (see 9.2). If any undissolved water is visually apparent (as determined by Test Methods D4176 or D4860, or both), discard and replace with a fresh sample.
7.2 After thoroughly mixing, if the original sample container is too large to easily handle, use an epoxy lined can or dark glass bottle as a transfer container to store an aliquot of the test sample. Prior to drawing the aliquot, rinse the transfer container three times with the product to be tested. Draw a representative 1 to 2-L aliquot from the sample container into a transfer container. (Warning - Because the situations under which samples are taken vary from laboratory to laboratory and from situation to situation, no firm recommendation for sampling can be given. It is the responsibility ofthe user of this test method to ensure the aliquot used in the test is representative of the lot of fuel.)
8. Preparation of Apparatus
8.1 Locate the apparatus on a level surface in an area where the temperature is between 15 and 25°C (59 and 77°F).
8.2 Open the case, and assemble the apparatus as shown in Fig. 2. Ifthe Tygon tubing (see 6.1.7) is not attached, as shown, carry out 8.2.1 to 8.2.2.
8.2.1 Attach one end of the Tygon tubing to the fuel reservoir container (6.1.5) and insert the plastic in-line splice coupler (6.1.8) into the other end.
8.2.2 Insert the plastic in-line coupler into another piece of Tygon tubing, thread the tubing in the peristaltic pump (see 6.1.1), as shown in Fig. 3, and clamp it in place by moving the lever arm counterclockwise.
NOTE 3 - The splice fitting prevents the tubing from being pulled into the pump during operation. This also allows easy replacement of the portion of the tubing that is depressed by the pump rollers. To extend the life of the Tygon tubing, when not in use, leave the clamp open or remove the tubing from the pump.
8.2.3 Insert one end of the horizontal section of the plastic tee coupler (6.1.9) into the tubing that is clamped in the pump, and attach two other sections of tubing to the other parts of the tee.
8.2.4 Connect the tubing that is connected to the perpendicular part ofthe tee to the pressure transducer. Insert the hose barbered portion ofthe Luer-Loc coupler (6.1.10) into the other section of tubing that is connected to the in-line part of the tee.
8.3 Attach the power pack to the connector on the top of the case, and connect the power pack to an ac power source. Turn the instrument on by depressing the ON switch, causing both the POWER and MODE A lights to illuminate.
8.4 Have a labeled FCell filter (see 6.2) ready for use.
8.5 Verification of Apparatus - As required in accordance with 4.3, verify apparatus performance by checking that the flow rate and the pressure transducer are within tolerance.
8.5.1 Check the flow rate by performing a purge cycle to eliminate any air from the system. Subsequently, perform a test using a fuel sample without a filter, collecting the sample in a graduate (see 6.3.1). Compare the volume collected with amount displayed. The amount displayed shall be approximately 300 mL, and the amount collected shall be 285 to 315 mL. Adjust the pump speed control (6.1.4), as required.
8.5.2 Check the pressure by inserting a pressure gage (see 6.3.2) at the end of the Tygon tubing where the filter would be installed. Perform a test using air only, and compare the readings when approximately 104 kPa (15 psi) is displayed. If the readings vary more than +/- 7 kPa (1.0 psi), return the apparatus to the manufacturer.
