1901-02-13 Waldemar Pruss Dampfwasserableiter Kaiserliches Patentamt Patentschrift Nr. 127617 Klasse 13 d, Seite 1 Ausschnitt, 13 February 1901

Extract from the patent specification dated february 13, 1901 no. 127617 class 13 d from the imperial patent office for the steam water trap by waldemar pruss in hanover. Date: 13 February 1901.