The current requirements for testing diffusers for maximum pore diameter and permeability in Annex A1 is overly prescriptive, such as requiring the use of a manometer and wet test meter, which means that if a lab were to use other equivalent devices capable of regulating/controlling pressure or flow rates respectively, the lab would not be in compliance with the current requirements. Currently, there are commercially available automated instruments that can accurately determine the maximum pore diameter and permeability of gas diffusers that dont rely on the use of a manometer and wet test meter. The proposed revision is to update Annex A1 to retain the current procedure as one way for determining the maximum pore diameter and permeability (so as to not preclude labs that are currently following these procedures), while providing labs with some flexibility to use other apparatus in meeting the functional requirements in the method (i.e., verifying that the diffusers used in the method meet the corresponding requirements for maximum pore diameter and permeability as defined in section 6.1 of the method). Comparative data has been collected involving an automated instrument versus the current method requirements as supporting justification for the proposed changes. The proposed revision was discussed at the December 2012 ASTM meeting where it was decided to initiate a ballot revision for the method.
foam (foaming): Foaming properties; Gear oils (GO); High-speed gearing; Lubricating oils; Maximum pore diameter; Permeability; Pore diameter; Pumps;
Citing ASTM Standards
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