ASTM D6082 High Temperature Foaming Characteristics of Lubricating Oils
6. Apparatus
6.1 Heating Bath, any heating system capable of maintaining a sample temperature of 150 +/- 1°C (see Fig. 2).
NOTE 1 - The precision of this test method was determined using only liquid baths.
6.1.1 Heating Transfer Fluid, any liquid with low volatility, at the test temperature, chemical stability and sufficient low viscosity to permit stirring.
NOTE 2 - A 4 to 7 mm2/s (cSt) polyalphaolefin has been found to be a suitable fluid. Silicone fluids are foam inhibitors and their use may alter the foam characteristics of the test sample and should be discouraged.
NOTE 3 - A slow purge of nitrogen gas through the fluid, or as a blanket over the bath fluid, reduces darkening (oxidation) of the bath fluid.
6.2 Graduated Cylinder, 1000 mL, fitted with a device to overcome buoyancy if a liquid bath is used and modified to have a circular top. It shall be capable of withstanding the extreme temperature conditions of this test method.
NOTE 4 - A heavy metal ring large enough to fit over the outside and rest on the bottom of the cylinder has been found to be suitable to overcome buoyancy.
NOTE 5 - Graduated cylinders having a pouring spout can be prepared for this test method by making a horizontal cut below the spout and removing the part above the cut. The cut edges of the cylinder should be fire-polished or smoothed by grinding.
6.3 Flow Meter and Regulator, calibrated and capable of maintaining air flow volume of 200 +/- 5 mL/min.
6.3.1 A gas volume meter graduated in hundredths of a litre, or a technically equivalent flow measuring device, with sufficient capacity to measure a flow rate of at least 6000 mL/min, while generating a back pressure of no more than 10 mm of water, is required.
6.4 Laboratory Oven, without fan, capable of maintaining 49 +/- 1°C.
6.5 Stirrer, capable of 500 rpm +/- 100 rpm, fitted with a 1 1/2-in., 3-blade, 1.5-pitch marine propeller.
6.6 Stainless Steel Diffuser, 5 µm stainless steel diffuser meeting the specifications of pore size 15 to 60 µm and permeability between 3000 to 6000 mL/min when tested according to the method given in Annex A1 (see Fig. 3).
6.6.1 Calibration verification of new diffusers and calibration after each set (10 samples or less) of evaluations is required.
6.7 Thermometer, or other temperature sensing device capable of measuring 150 +/- 0.2°C. An ASTM thermometer Specification E 1 No. 41C-86, or equivalent, is suitable.
6.8 Timing Device, capable of measuring minutes and seconds (+/-1 s).
6.9 High Speed Blender, with a container capacity of one litre, capable of maintaining a speed of 22 000 rpm (+/-2000).
7. Reagents
7.1 Purity of Reagents - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents 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 sufficiently high purity to permit its use without lessening the accuracy of the determination.
7.2 Acetone. (Warning: See Note 6.)
NOTE 6 - Warning: Extremely flammable. Vapors may cause flash fire.
7.3 Compressed Air, hydrocarbon free and dry to a dew point of -60°C or lower.
7.4 Heptane. (Warning: See Note 7.)
NOTE 7 - Warning: Flammable. Vapor harmful.
7.5 Propan-2-ol. (Warning: See Note 7.)
7.6 Toluene. (Warning: See Note 7.)
NOTE 8 - Solvents with equivalent cleaning characteristics can be substituted for toluene.
8. Hazards
8.1 Warning - Users of this test method shall be fully trained and familiar with all normal laboratory practice, or under the immediate supervision of such a person. It is the responsibility of the operator to ensure that all local legislative and statutory requirements are met.
8.2 Warning - Cleaning solvents have flash points lower than usual laboratory ambient temperatures. Avoid the possibility of a fire or explosion.
8.3 Precaution - The fumes from the test oil and bath must be vented in a manner compatible with local environmental regulations.
8.4 Warning - Some apparatus assemblies can have as much as 20 L of bath oil at 150°C. Therefore, in the event of a breakage of the containing vessel, suitable containment of the spill is advisable.
