ASTM D721-02 pdf free.Standard Test Method for Oil Content of Petroleum Waxes.
OThis method covers the determination of the accept-ability of porous filter sticks used for filtration in Test MethodD72i. This method establishes the maximum pore diameterand also provides a means of detecting and measuring changeswhich occur form continued use.maximum pore diameterthe diameter in micrometers of the largest opening in the filter.It is recognized that the maximum pore diameter asdefined herein does not necessarily indicate the physical dimensions of thelargest pore in the filter. It is further recognized that the pores are highlyirregular in shape. Because of the irregularity in shape and otherphenomena characteristic of filtration, a filter may be expected to retain allparticles larger than the maximum pore diameter as defined and deter-mined herein,and will generally retain particles which are much smallerthan the determined diameter.
The filter is cleaned and wetted with water. It is thenimmersed in water and air pressure is applied against its uppersurface until the first bubble of air passes through the filter. Themaximum pore diameter is calculated from the surface tensionof water and the applied pressure.
Pressure Measuring Device, mercuryfilled manom-eter or equivalent,capable of measuring pressures in incre-ments of 0.5 mm of Hg.Air Supply, clean and filtered.Air Pressure Regulator, needle-valve type.X1.4.4 Drying Oven.
Clean the filter sticks by soaking in concentratedhy drochloric acid,and then wash them with distilled water.Rinse with acetone, air dry, and place in drying oven at 220F( 105°C) for 30 min.Thoroughly wet the clean filter to be tested bysoaking it in distilled water.
Assemble the apparatus as shown in Fig. Apply pressure slowly from a source of clean air.
mmerse the filter just below the surface of thewater.If a head of liquid exists above the surface of the filter, theback pressure produced must be deducted from the observed pressure.X1.5.5 Increase the air pressure to 10 mm below theacceptable pressure limit and then at a slow uniform rate ofabout 3 mm Hg/min until the first bubble passes through thefilter. This can be conveniently observed by placing the beakeror test tube over a mirror. Read the manometer when the firstbubble passes off the underside of the filter.ASTM D721 pdf download.
ASTM D721-02 pdf free
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