DIN 28138-1
DIN 28138-1 Rotating mechanical seals for agitator shafts - Part 1: Carbon or stainless steel - Operating data, assembly dimensions
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 06/01/2006
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 06/01/2006