Ahlstrom 631 Standard Qualitative Filter Papers are used for the filtration of coarse particle and gelatinous precipitates such as ferric aluminum and magnesium hydroxides. Grade 631 is used in air monitoring and gas filtration when a high flow rate is needed. This grade is also found in routine cleanup and analysis of insoluble liquids such as biological fluids and organic elements.

Standard qualitative filter papers are suitable for quadrant folded or gravity flow applications. These grades contain a high level of alpha-cellulose that provides high purity but will weaken when wet. The inherent strength of standard (untreated) grades does not pose a problem when they are used in routine quadrant folded applications. Not recommended for use in vacuum work or when went handling is required.

Key Features

• Retention: 10.0µm
• Filtration Speed: 34 sec/100mls (Herzberg), 200 mls/min (Rapidity)
• High Loading Capacity
• Equivalent to Grade 4