浮頂油罐上部是敞開的，罐(guan)頂只是漂浮在罐內油面上隨油面的升降而升降的浮盤，浮盤外徑比罐壁內徑小400～600mm，用以裝設密封裝置，以防止這一環狀間隙中的油品產生蒸發損壞，同時防止風沙雨雪等污染油品。密封裝置形式很多，常用的有彈性填料密封或管式密封。

  浮(fu)(fu)頂(ding)(ding)油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)當(dang)罐(guan)(guan)(guan)(guan)頂(ding)(ding)隨油(you)(you)(you)(you)面(mian)下降至罐(guan)(guan)(guan)(guan)底時，油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)就變(bian)為上(shang)(shang)部(bu)敞開的(de)立式(shi)圓筒形容(rong)器，若此時遇大(da)風，罐(guan)(guan)(guan)(guan)內易形成(cheng)真空(kong)，如真空(kong)度過大(da)罐(guan)(guan)(guan)(guan)壁(bi)有(you)可能被壓(ya)癟，為此在(zai)靠近(jin)頂(ding)(ding)部(bu)的(de)外側設置抗風圈。由于罐(guan)(guan)(guan)(guan)頂(ding)(ding)在(zai)罐(guan)(guan)(guan)(guan)內上(shang)(shang)下浮(fu)(fu)動，故(gu)罐(guan)(guan)(guan)(guan)壁(bi)板只能采用(yong)對接(jie)焊接(jie)并且內壁(bi)要取(qu)平(ping)。浮(fu)(fu)頂(ding)(ding)油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)罐(guan)(guan)(guan)(guan)頂(ding)(ding)與(yu)油(you)(you)(you)(you)面(mian)之間基本上(shang)(shang)沒有(you)氣(qi)相(xiang)空(kong)間，油(you)(you)(you)(you)品(pin)沒有(you)蒸發(fa)(fa)(fa)的(de)條件，因(yin)而沒有(you)因(yin)環(huan)(huan)境溫度變(bian)化(hua)而產(chan)生(sheng)的(de)油(you)(you)(you)(you)品(pin)損耗，也基本上(shang)(shang)消除(chu)了(le)因(yin)收(shou)、發(fa)(fa)(fa)油(you)(you)(you)(you)而產(chan)生(sheng)的(de)損耗，避(bi)免污染環(huan)(huan)境，減少(shao)發(fa)(fa)(fa)生(sheng)火災的(de)危(wei)險(xian)性。所以盡管(guan)這種油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)鋼材耗量(liang)和安裝費(fei)用(yong)比拱頂(ding)(ding)油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)大(da)得多，但(dan)對收(shou)發(fa)(fa)(fa)油(you)(you)(you)(you)頻繁(fan)的(de)油(you)(you)(you)(you)庫(ku)、煉油(you)(you)(you)(you)廠原油(you)(you)(you)(you)區等仍應優先選用(yong)，用(yong)于儲存原油(you)(you)(you)(you)、汽(qi)油(you)(you)(you)(you)及(ji)其他揮發(fa)(fa)(fa)性油(you)(you)(you)(you)品(pin)。

  浮(fu)(fu)頂(ding)(ding)(ding)(ding)罐(guan)(guan)的(de)(de)(de)(de)種類很多，有(you)單(dan)(dan)盤(pan)(pan)式(shi)、雙盤(pan)(pan)式(shi)、浮(fu)(fu)子式(shi)等(deng)。常用的(de)(de)(de)(de)單(dan)(dan)盤(pan)(pan)式(shi)浮(fu)(fu)頂(ding)(ding)(ding)(ding)罐(guan)(guan)在浮(fu)(fu)頂(ding)(ding)(ding)(ding)周(zhou)圍(wei)建造環(huan)形浮(fu)(fu)船，用隔板(ban)將浮(fu)(fu)船分隔成(cheng)若干個不(bu)滲漏的(de)(de)(de)(de)船室，在環(huan)形浮(fu)(fu)船范圍(wei)內的(de)(de)(de)(de)面(mian)積以(yi)(yi)單(dan)(dan)層金(jin)(jin)屬(shu)(shu)板(ban)覆蓋。而雙盤(pan)(pan)式(shi)浮(fu)(fu)頂(ding)(ding)(ding)(ding)罐(guan)(guan)的(de)(de)(de)(de)浮(fu)(fu)頂(ding)(ding)(ding)(ding)則是(shi)上(shang)、下兩面(mian)分別以(yi)(yi)金(jin)(jin)屬(shu)(shu)板(ban)覆蓋。不(bu)論是(shi)單(dan)(dan)盤(pan)(pan)浮(fu)(fu)頂(ding)(ding)(ding)(ding)罐(guan)(guan)還是(shi)雙盤(pan)(pan)浮(fu)(fu)頂(ding)(ding)(ding)(ding)罐(guan)(guan)，浮(fu)(fu)盤(pan)(pan)上(shang)面(mian)都安裝有(you)梯子、平臺和欄(lan)桿。建造浮(fu)(fu)頂(ding)(ding)(ding)(ding)的(de)(de)(de)(de)金(jin)(jin)屬(shu)(shu)材料(liao)有(you)碳(tan)鋼和鋁(lv)合(he)金(jin)(jin)兩種，目(mu)前，碳(tan)鋼材料(liao)的(de)(de)(de)(de)浮(fu)(fu)頂(ding)(ding)(ding)(ding)已逐漸被鋁(lv)合(he)金(jin)(jin)浮(fu)(fu)頂(ding)(ding)(ding)(ding)所替代。浮(fu)(fu)頂(ding)(ding)(ding)(ding)一般在專門(men)的(de)(de)(de)(de)制造廠建造，作為成(cheng)品部件供貨。