6. Apparatus
6.1 Evaporation Cell, as described in Annex A1.
6.2 Air Supply System, capable of supplying to the cell the required flow of air free of entrained particles (Warning - See Note 2). A 410-mm (16-in.) length of 1-in. diameter pipe packed with glass wool has been found satisfactory for filtering the air.
NOTE 2 - Warning: Compressed gas under high pressure. Use with extreme caution in the presence of combustible material, since the autoignition temperatures of most organic compounds in air are drastically reduced at elevated pressures. See Annex A2.1.
6.3 Oil Bath, as described in Annex A1.
NOTE 3 - Other constant-temperature baths may be used if the exit air passing over the grease sample is at the test temperature (+/-0.5K (1°F)).
6.4 Thermometers - ASTM thermometers graduated in either Celsius or Fahrenheit degrees and having a range from -5 to 400°C (20 to 760°F) and conforming to the requirements for Thermometers 3C or 3F, respectively, as described in Specification E 1.
6.5 Flowmeter - A rotameter calibrated to deliver air at a rate of 2.583 +/- 0.02 g/min between 289 and 302K (60 and 85°F) (2 L/min at standard temperature and pressure). It shall be furnished with a needle valve and mounted as shown in Fig.1.
6.6 Oil Sample Cup, as described in Fig. 1 and A1.1.2.
7. Calibration of Equipment
7.1 It is assumed that equipment conforming to Test Method D972 in design and installation needs no calibration. If questions arise, carry out the procedure using m-terphenyl (Warning - See Note 4) of good commercial quality. The following two points shall be determined:
If the data do not fall within the above ranges, check flow rate and temperature. If these are correct, prepare a substitute equation for k' similar to Eq 2 and use it in Section 10. When use of nonreactive gas is required, this calibration is necessary as standard cell constants are not valid for gases other than air.
NOTE 4 - Warning: Harmful or fatal if swallowed. See A2.2.
7.2 If the apparatus specified in Test Method D2595 is to be used, it shall be calibrated as described in 7.1.