ASTM D7224 Standard Test Method for Determining Water Separation Characteristics of Kerosine-Type Aviation Turbine Fuels Containing Additives by Portable Separometer
13. Procedure
13.1 Select Mode A Operation:
13.1.1 Depress push-button A (Mark V) or Jet A (Mark X) for Mode A operation. Sequential illumination of the lettered push-buttons will cease and the depressed push-button will stay lit. The correct syringe drive speed is set automatically.

13.2 Depending on which syringe is used, the following procedure shall be followed:
13.2.1 Plastic Syringe - Remove the plunger from a new 50 mL plastic syringe and wipe the tip using a clean, lintless wipe to remove any sheen caused by excess lubricant. Insert a plug into the exit hole of the syringe barrel, add 50 mL +/- 1 mL of fuel, and place the syringe barrel on the emulsifier mount, turning to lock in place.
13.2.1.1 To mitigate the buildup of static charge, only nitrile gloves are recommended for use while handling the syringe barrel.

13.2.2 Aluminum Syringe - Flush the barrel of the 50 mL aluminum syringe, and wipe the plunger tip with toluene or clean jet fuel using a clean, lintless wipe to remove any residue deposited from the previous test. Insert a plug into the exit hole of the syringe barrel, add 50 mL +/- 1 mL of fuel to the scribe mark in the syringe barrel (see Fig. 5), and place the syringe barrel on the emulsifier mount, turning to lock in place.

13.2.3 Ensure that the syringe barrel is properly aligned concentrically with the mixer shaft and not touching the propeller. Proper alignment can be verified by grasping the syringe barrel and moving it until the propeller on the end of the mixer shaft is free and not touching. Misalignment can cause damage to the propeller by the barrel of the aluminum syringe, slow the mixer causing a poor emulsion, and create shavings from the plastic syringe to form and collect on the coalescer filter material, or both, resulting in erroneous test results. This alignment requirement applies to all instruments manufactured prior to July 1988 which have not been serviced by EMCEE Electronics, Inc. since that date. Since July 1988, with ASTM approval, all new instruments and those returned for service have had a standoff installed on the mixer shaft to prevent the syringe barrel from coming into contact with the mixer blades.

13.3 Initiate the first CLEAN cycle by depressing the START (Mark V) or CLEAN 1 (Mark X) push-button as designated by the annunciator light. (Warning - Do not operate the mixer without having a syringe with fuel in place. The mixer bearings depend on the fuel for lubrication.)

NOTE 8 - The Mark X will illuminate ERROR ALERT and display an ERR-05 when the emulsifier speed is outside of acceptable limits.

13.4 At the end of the first clean cycle, when the mixer motor stops, remove the syringe barrel from the emulsifier, discard the fuel, and drain the syringe thoroughly. Add 50 mL +/- 1 mL of fresh fuel into the syringe, and place the syringe barrel on the emulsifier mount. Turn to lock in place.

13.5 Second Clean Cycle:
13.5.1 Mark V Deluxe - Initiate the second CLEAN cycle by sequentially pressing the RESET, A, and the START pushbuttons, as designated by the annunciator lights.

13.5.2 Mark X - Initiate the second CLEAN cycle by pressing the CLEAN 2 pushbutton.

13.6 Add about 15 mL to 20 mL of the fuel to be tested into a new vial. Wipe the outside of the vial with a clean, lintless wiper, and insert the vial into the turbidimeter well, aligning the black mark on the vial at 90° from the white line on the front of the turbidometer well. Rotate the vial until the black mark on the vial aligns with the white line on the front of the turbidometer well (Fig. 1).

13.7 At the end of the second clean cycle, when the mixer motor stops, remove the syringe barrel from the emulsifier, discard the fuel, and drain the syringe thoroughly. Add 50 mL +/- 1 mL of fresh fuel sample into the syringe.
13.7.1 Handle the syringe in such a manner as to minimize warming of the fuel sample by body heat.

13.8 Using a fresh plastic tip on the hand pipet, add 50 µL of distilled water to the fuel sample as follows: Holding the pipet in hand, give a slight twist to the plastic tip to ensure a tight seal. Push in the plunger, immerse the tip just below the water surface, release the plunger, and withdraw from the water slowly to avoid water drops adhering to the outside of the tip. Immerse the tip of the pipet just below the fuel surface in the center of the syringe (Fig. 6) to ensure the water drops break away cleanly and fall to the bottom, push and hold-in the plunger, withdraw the pipet, and release the plunger.

13.9 Place the syringe barrel on the emulsifier mount, turning to lock in place.

13.10 The Mark V automatic portion of the applicable test mode program listed in Table 3 is initiated, with the syringe in place, by depressing the START push button.
13.10.1 The automatic program starts with a read meter indication (four short tones) followed by a 10 s full-scale adjustment period. During this period, the ARROWED push-buttons will illuminate and can be depressed to adjust the meter to read 100 (Fig. 8). If the adjustment cannot be completed at this time, final adjustment may be accomplished during the second meter adjust period occurring later in the test sequence.

13.11 The Mark X automatic portion of the applicable test mode program listed in Table 3 is initiated, with the syringe in place, by depressing the RUN pushbutton.
13.11.1 The automatic program starts with a read meter indication (four short tones) followed by a 2 s to 30 s adjustment period. During this period, the turbidimeter will automatically adjust to 100. If the adjustment cannot be completed at this time, the ERROR ALERT will illuminate and an ERR-04 will be displayed.

13.12 If for any reason it is desired to interrupt the sequence and start over, pushing the RESET push-button on the Mark V or the Mark X instrument will cancel the test in progress and reset the program to the beginning of the CLEAN segment of the test cycle.

13.13 After the full-scale adjustment period the mixer motor activates and the emulsion process is initiated.

NOTE 9 - A few drops of fuel may seep from the hole in the emulsifier head during the high-speed mixing operation. This should not affect the test results.

13.14 When the mixer stops (after emulsification), remove the syringe barrel from the emulsifier and partially insert the plunger to seal the open end of the syringe (Fig. 9). Invert the syringe (exit hole up), remove the plug, and exhaust the entrapped air in the syringe barrel without significant fuel loss by carefully inserting the plunger to the scribe mark on the plunger (the 50 mL mark). Use a clean wiper over the exit hole to capture the small amounts of fuel which may be extruded as foam. Affix the plastic connector to the barrel of the aluminum syringe and attach a new MCell Coalescer to the other end of the connector (Fig. 10). The plastic connector is not required with a plastic syringe.
13.14.1 To facilitate ease of insertion of the plunger into the syringe barrel, wet the tip of the plunger with some of the sample fuel.

13.14.2 Place the entire syringe assembly into the syringe drive mechanism (Fig. 11). To minimize the effect of plunger resistance (drag) in the syringe barrel, align the syringe assembly vertically in the syringe drive mechanism with the end of the syringe plunger parallel with the push bar of the syringe drive mechanism. Position a waste container beneath the MCell Coalescer to collect the unwanted portion of the processed fuel sample during the coalescing period.

13.14.3 Electrically bond MCell Coalescers to the Micro-Separometer instrument to prevent buildup of an electrostatic charge that could result in ignition of flammable test fluids. Each Mark V and Mark X instrument is furnished with a ground lead that has an alligator clip on one end and a banana plug on the other. Fasten the alligator clip to the MCell Coalescer and insert the plug into the chassis ground jack (Fig. 11).

13.15 Four short tones will indicate the second meter adjustment period. If required (Mark V), adjust the meter reading to 100. The syringe drive mechanism will start down at the end of the meter adjust period forcing the water/fuel emulsion through the MCell Coalescer. During this operation remove the vial from the turbidimeter well, and discard the fuel.

13.16 Collect the last 15 mL of fuel sample being processed from the MCell Coalescer (Fig. 12) when the "collect sample" annunciator lamp (marked C/S) illuminates and a pulsed tone of short duration sounds. To lessen the amount of air introduced into the fuel during this operation, position the vial at a slight angle and allow the fuel to flow down the inner surface. Remove the vial just prior to when the last amount of sample is expelled from the MCell Coalescer.

13.17 Wipe the outside of the vial with a clean, lintless wiper to remove any fingerprints and fuel. Place the sample vial into the turbidimeter well aligning the marks on the vial and on the control panel in front of the well. (Fig. 1) At the end of the settling time (1 min), a steady (4 s duration) tone will alert the operator that the meter is about to activate.

13.18 At the end of the tone, the METER will automatically activate for approximately 10 s.
13.18.1 Read the MSEP rating at the midpoint of the 10 s meter read cycle indicated by a short 1 s tone.

NOTE 10 - The Mark X stores the reading until another test is performed.

NOTE 11 - Numerical values obtained outside the measurement range from 50 to 100 are undefined and invalid (see 5.4 and Note 1)