ASTM D6217 for Particulate Contamination in Middle Distillate Fuels by Laboratory Filtration
6. Apparatus
6.1 Filtration System - Arrange the following components as shown in Fig. 1.
6.1.1 Funnel and Funnel Base, with filter support for a 47 mm diameter membrane, and locking ring or spring action clip.
6.1.2 Ground/Bond Wire, 0.912-2.59 mm (No. 10 thru No. 19) bare stranded flexible, stainless steel or copper installed in the flasks and grounded as shown in Fig. 1.
NOTE 2 - The electrical bonding apparatus described in Test Method D5452 or other suitable means of electrical grounding which ensure safe operation of the filtration apparatus and flask can be used. If the filtrate is to be subsequently tested for stability it is advisable not to use copper as copper ions catalyze gum formation during the stability test.
6.1.3 Receiving Flask, 1.5 L or larger borosilicate glass vacuum filter flask, which the filtration apparatus fits into, equipped with a sidearm to connect to the safety flask.
6.1.4 Safety Flask, 1.5 L or larger borosilicate glass vacuum filter flask equipped with a sidearm to connect the vacuum system. A fuel and solvent resistance rubber hose through which the grounding wire passes shall connect the sidearm of the receiving flask to the tube passing through the rubber stopper in the top of the safety flask.
6.1.5 Vacuum System, either a water aspirated or a mechanical vacuum pump may be used if capable of producing a vacuum of 1 to 100 kPa below atmospheric pressure when measured at the receiving flask.
6.2 Other Apparatus:
6.2.1 Air Ionizer, for the balance case. Air ionizers shall be replaced within one year of manufacture.
NOTE 3 - When using a solid-pan balance, the air ionizer may be omitted provided that, when weighing a membrane filter, it is placed on the pan so that no part protrudes over the edge of the pan.
6.2.2 Analytical Balance, single- or double-pan, the precision standard deviation of which must be 0.07 mg or less.
6.2.3 Crucible Tongs, for handling clean sample container lids.
6.2.4 Drying Oven, naturally convected (without fan-assisted air circulation), controlling to 90 +/- 5°C.
6.2.5 Flushing Fluid Dispenser, an apparatus for dispensing flushing fluid through a nominal 0.45 µm membrane filter.
NOTE 4 - An apparatus such as pictured in Fig. 2 has been found suitable for this task. A standard laboratory wash bottle can also be used provided the flushing fluid is pre-filtered through a 0.45-µm pore size membrane filter and precautions are taken to maintain appropriate cleanliness of the interior of the wash bottle
6.2.6 Forceps, approximately 12 cm long, flat-bladed, with non-serrated, non-pointed tips.
6.2.7 Graduated Cylinders, to contain at least 1 L of fluid and marked at 10 mL intervals. 100 mL graduated cylinders may be required for samples which filter slowly.
6.2.8 Petri Dishes, approximately 12.5 cm in diameter, with removable glass supports for membrane filters.
NOTE 5 - Small watch glasses, approximately 5 to 7 cm in diameter, have also been found suitable to support the membrane filters.
7. Reagents and Materials
7.1 Purity of Reagents - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficient purity to permit its use without lessening the accuracy of the determination.
7.2 Purity of Water - Unless otherwise indicated, references to water mean reagent water as defined by Type III of Specification D1193.
7.3 Flushing Fluids:
7.3.1 Heptane (Warning - See Note 6)
7.3.2 2,2,4-trimethylpentane (isoctane) (Warning - See Note 6)
7.4 Propan-2-ol (2-propanol; isopropyl alcohol), (Warning - See Note 6.)
NOTE 6 - Warning - Flammable
7.5 Liquid or Powder Detergent, water-soluble, for cleaning glassware.
7.6 Nylon Test Membrane Filters, plain, 47-mm diameter, nominal pore size 0.8-µm.
7.7 Nylon Control Membrane Filters (see Note 7), 47-mm diameter, nominal pore size 0.8-µm.
NOTE 7 - Membrane filters with a grid imprinted on their surface, may be used as control membrane filters for identification.
7.8 Protective Cover, polyethylene film or clean aluminum foil.
