Ukuvalwa kwesigaba sokuqala sokuthuthukiswa kobuchwepheshe
Phakathi kuka-1926 no-1933, umsunguli nomenzi wemishini wase-Danish u-NielsA Christensen waqhubeka wathuthukisa futhi wasebenzisa lolu hlobo lombuthano.Indlela yakhe (O-ring) yanyatheliswa ngo-1930, inelungelo lobunikazi ngo-1933, futhi yazuza umklomelo omkhulu ngo-1938.
Isikhathi sokuthumela: Nov-07-2022
