Approaching a problem on sealing device in external floating roof oil tank

Makes an on-site investigation on untight seal and over compressed seal existed in seal device of external floating roof oil tank during production operation and analyzes reasons of this problem occurred.Points out that main reason for untight seal and over compressed seal comes from oil tank foundation's settlement, deviation of tank wall perpendicularity and ovality.Puts forward a construction control method, especially strengthens quality control in oil tank shell plate fabrication, raises quality in installation of bottom ring shell plate, control ring by ring the perpendicularity of shell plate over the second ring, distributes control deviation of integral perpendicularity into each ring of shell plate.Recommends not only technical level shall be raised but also personnel quality awareness shall be strengthened in large-scaled, storage tank's construction, and detail stipulation shall be set up for uneven settlement value and water feeding pressure planning for large-scaled storage tank.