ASTM D7224 Standard Test Method for Determining Water Separation Characteristics of Kerosine-Type Aviation Turbine Fuels Containing Additives by Portable Separometer
7. Apparatus
7.1 Micro-Separometer Instrument 7 is used to perform the test. The unit is completely portable and self-contained, capable of operating on an (optional) internal rechargeable battery pack or being connected to an ac power source using power cords which are available for various voltages. Connection to an ac power source will provide power to the unit and effect battery recharge. The power cords, test accessories and operators manual can be packed in the cover of the lockable case.

NOTE 2 - An extensive study was performed to verify that the Mark X Micro-Separometer instrument gives equivalent results to the Mark V Deluxe Micro-Separometer instrument. See Research Report RR:D02-1647.

NOTE 3 - The Mark X has a universal power supply and requires only one power cord as compared to the Mark V Deluxe that requires individual power cords for different voltages.

7.1.1 Review the Operating Manual of the Micro-Separometer instrument that is furnished with each unit (and is also available from the manufacturer's website) for operating instructions. The instrument is not field repairable. Also note that this instrument is designed to perform a number of different functions in addition to this specific test method.

7.1.2 The Micro-Separometer Mark V Deluxe and Mark X instruments and associated control panels are shown in Fig. 1 and Fig. 2, respectively. The emulsifier is on the right side of the raised panel and the syringe drive mechanism is on the left side. The control panel containing the operating controls is mounted on the fixed panel in the left side of the case. Table 1 lists the manual and audio operating characteristics of the instrument.

7.1.3 All of the controls are located in a push-button array on the control panel. The push-buttons illuminate when depressed thus indicating operational status. A circuit breaker located on the control panel provides protection for the ac power circuit.
7.1.3.1 The Mark X has an LCD display on the control panel that provides information to the operator during the test. The information includes test status and an error code that defines a malfunction in the Micro-Separometer instrument.

7.1.4 The turbidimeter is located under the main control panel and consists of a well in which the sample vial is placed (in a specified orientation), a light source and a photocell.

7.1.5 By depressing the ON push-button, the electronic circuits are energized. The ON push-button pulses on and off when the instruments are being operated by an ac source and remains constantly on when the battery (dc) pack is used. The lettered push-buttons will sequentially illuminate indicating READY operational status.

NOTE 4 - Of the lettered (A-G) pushbuttons on the control panel of the Mark V Deluxe, only the A pushbutton is applicable to this test method. Of the lettered (Jet A - Diesel) pushbuttons on the control panel of the Mark X, only the Jet A pushbutton is applicable to this test method.

7.1.6 The RESET push-button can be depressed at any time to cancel the test in progress and restore the program to the initial start mode. The lettered push-buttons commence to sequentially illuminate, thus indicating a READY operational status enabling test mode selection.

7.2 Mark V Operation:
7.2.1 Depress the A push-button to select test Mode A. The depressed push-button and the START push-button will illuminate.

7.2.2 The START push-button, when depressed initially, initiates the CLEAN cycle causing the syringe drive mechanism to travel to the UP position and the emulsifier motor to operate for the cleaning operation.

7.2.3 The START push-button, when depressed after the second CLEAN cycle initiates the automatic program sequence causing the read indicator and the two ARROWED push-buttons to illuminate, indicating that a full-scale adjustment period is in effect. A numerical value also appears on the display.

7.2.4 By depressing the appropriate ARROWED push-button, the displayed value on the meter can be increased or decreased, as required, to attain the 100 reference level for the vial of fuel sample in the turbidimeter.

7.3 Mark X Operation:
7.3.1 Selection of Test Mode A program is accomplished by depressing the Jet A lettered pushbutton. The depressed push-button illuminates and the sequential illumination of the other lettered pushbuttons ceases. The CLEAN 1 pushbutton also illuminates.

7.3.2 The first and second clean cycles are initiated by depressing the CLEAN 1 and CLEAN 2 pushbuttons. The RUN pushbutton will illuminate at the end of the second clean cycle.

7.3.3 The automatic portion of the test sequence is initiated by depressing the RUN pushbutton.

7.3.4 The 100 reference level for the vial of fuel in the turbidimeter is set automatically and does not require any adjustment. If the turbidimeter could not auto adjust to 100, the error alert indicator illuminates and an ERR-04 is displayed.

7.4 Accessory equipment and expendable materials needed to perform the test are shown in Fig. 3 and consist of the following:
7.4.1 Connector (A) - A plastic connector used to affix the MCell Coalescer 6 to the aluminum syringe barrel. The connector is not required with the plastic syringe.

7.4.2 Syringe Plug (B) - A plastic plug used to stopper the syringe during the CLEAN and EMULSION cycles.

7.4.3 Syringe, (Barrel (C) and Plunger (D)), either:
7.4.3.1 A single use plastic syringe and plunger, which is furnished in each six-pack (7.5), or

7.4.3.2 A reusable aluminum syringe and plunger. The barrel of the aluminum syringe has an internal, circumferential scribe mark that indicates the 50 mL fill level (Fig. 4). The plunger has an external, circumferential scribe mark that indicates the point of insertion in the syringe barrel to where the plunger tip comes into contact with the fuel.

7.4.3.3 Use of syringes other than those demonstrated to be free of surfactant contamination in a precision program such as described in Section 15 will render test results invalid.

7.4.4 Vials, (E) - A 25 mm outside diameter vial premarked for proper alignment in the turbidimeter well.

7.4.5 MCell Coalescer, (F) - An expendable coalescer cell with a tapered end in which the plastic connector is inserted. The other end of the plastic connector is inserted in the tapered end of the syringe barrel. Coalescer is labeled in red background with black lettering:
MCell, JET FUEL. D7224

7.4.6 Plastic Tip and Pipet, (G) with (H) - A disposable plastic tip and an automatic 50 µL hand pipet. Plastic tips are supplied with each six-pack and a pipet is supplied with each Micro-Separometer.

7.4.7 Distilled Water (I) - A clean container of double-distilled water. A container of double-distilled water is supplied with each six-pack. A holder for the water container is affixed to the control panel (Fig. 11).

7.4.8 Beaker, Catch Pan, or Plastic Container - (supplied with each Micro-Separometer) used to receive the waste fuel during the coalescing period of the test (not shown).

7.5 A plastic connector, syringe plug, test sample vial, MCell Coalescer, plastic syringe with plunger, pipet tip and distilled water are used in each test. These expendable materials are packaged so that each package has sufficient expendables to perform one test. Six of these packages, including a container of double-distilled water, are included in a kit containing supplies for six tests. This kit is termed the Micro-Separometer Six-Pack (Fig. 5).

8. Reagents and Materials
8.1 Aerosol OT (AOT), solid (100 % dry) bis-2-ethylhexyl sodium sulfosuccinate.

8.2 Toluene, ACS reagent grade. (Warning - Flammable. Vapor harmful.).

8.3 Dispersing Agent, Toluene solution (Warning - Flammable. Vapor harmful.) containing 1 mg of AOT per millilitre of toluene.

8.4 Reference Fluid Base - A surfactant-free clean hydrocarbon material which is used to verify proper operation and is prepared in the manner described in Appendix X1. (Warning - Flammable. Vapor harmful.)

8.5 Reference Fluid - (Warning - Flammable. Vapor harmful.) A fluid used for checking the operational performance of the Micro-Separometer instrumentation, consisting of increasing concentrations (0.0 mL/L to 0.8 mL/L) of dispersing agent added to the reference fluid base. The MSEP ratings for this range of concentration appear in Table 2 for Jet A, Jet A-1, JP-5, JP-7, and JP-8 fuels using Mode A. The reference fluids are tested as described in Section 13. If the results do not fall within the range of limits shown in Table 2, the reference fluid shall be discarded and a fresh quantity of reference fluid prepared and the validation repeated. Repeated out-of-tolerance test results are cause for returning the instrument to the factory for adjustment and calibration. (Refer to the Operators Manual.)

NOTE 5 - The reference fluid base without any dispersing agent should have a minimum MSEP rating of 97; otherwise, the results may not be indicative of the accuracy of the instrument.

8.5.1 Reference fluids shall be prepared by adding dispersing agent (8.3) to a suitable quantity of reference fluid base contained in a properly equilibrated container or graduate.
8.5.1.1 If a new or non-equilibrated container is used, the additive can adsorb on the walls and the MSEP ratings can erroneously improve significantly. To equilibrate the container surface, an additive blend should be held for a minimum of 24 h in the container, discarded, and replaced with a fresh blend.

8.6 Water, clean, double-distilled and surfactant-free (furnished with each six-pack).
8.6.1 Use ofwater other than double-distilled water (such as tap or deionized water) will render test results invalid.

9. Hazards
9.1 The primary hazard in this test method is the flammability of the fuels that are tested. Take suitable precautions to avoid sparks, flames or sources of ignition.

9.2 Minimize worker exposure to breathing fuel vapors.