Corning Pyrex® Kjeldahl flasks have tooled finished necks for extra strength and uniform rubber stopper fit. Wall thickness is controlled to offer the optimum balance between thermal shock and chemical resistance. They can be used in ASTM E-258 procedures. Care must be taken to ensure the bottoms of the Kjeldahl flasks do not come in contact with the heating elements. Most Kjeldahl equipment manufacturers have ring supports for this purpose. Reference: ASTM E-1377.
These KIMAX® Kjeldahl flasks have a reinforced bead at the top and are designed from ASTM Specification E1377, Type I requirements. The neck is tooled to take a rubber stopper especially made for Kjeldahl flasks providing an accurate stopper fit and reducing the possibility of breakage in use.