浮頂油罐上部是敞開的，罐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)頂(ding)(ding)油(you)(you)(you)(you)(you)(you)罐(guan)(guan)當罐(guan)(guan)頂(ding)(ding)隨油(you)(you)(you)(you)(you)(you)面(mian)下降(jiang)至罐(guan)(guan)底時(shi)，油(you)(you)(you)(you)(you)(you)罐(guan)(guan)就變為上(shang)部敞開(kai)的(de)立(li)式(shi)圓筒形(xing)容器，若此(ci)時(shi)遇大風(feng)，罐(guan)(guan)內(nei)易形(xing)成真空(kong)，如真空(kong)度(du)過大罐(guan)(guan)壁有(you)可能(neng)被壓癟，為此(ci)在靠近頂(ding)(ding)部的(de)外側(ce)設置(zhi)抗風(feng)圈。由于(yu)罐(guan)(guan)頂(ding)(ding)在罐(guan)(guan)內(nei)上(shang)下浮(fu)動，故罐(guan)(guan)壁板只能(neng)采(cai)用(yong)對接(jie)焊接(jie)并且內(nei)壁要取平。浮(fu)頂(ding)(ding)油(you)(you)(you)(you)(you)(you)罐(guan)(guan)罐(guan)(guan)頂(ding)(ding)與油(you)(you)(you)(you)(you)(you)面(mian)之間基本(ben)上(shang)沒有(you)氣(qi)相空(kong)間，油(you)(you)(you)(you)(you)(you)品(pin)(pin)沒有(you)蒸發(fa)的(de)條件，因(yin)而沒有(you)因(yin)環境溫(wen)度(du)變化而產生的(de)油(you)(you)(you)(you)(you)(you)品(pin)(pin)損(sun)耗，也基本(ben)上(shang)消除了因(yin)收、發(fa)油(you)(you)(you)(you)(you)(you)而產生的(de)損(sun)耗，避免污染(ran)環境，減少發(fa)生火(huo)災的(de)危險性(xing)。所以(yi)盡管這(zhe)種油(you)(you)(you)(you)(you)(you)罐(guan)(guan)鋼(gang)材耗量和安裝費用(yong)比(bi)拱(gong)頂(ding)(ding)油(you)(you)(you)(you)(you)(you)罐(guan)(guan)大得多，但對收發(fa)油(you)(you)(you)(you)(you)(you)頻繁的(de)油(you)(you)(you)(you)(you)(you)庫(ku)、煉油(you)(you)(you)(you)(you)(you)廠原油(you)(you)(you)(you)(you)(you)區等仍應優(you)先選用(yong)，用(yong)于(yu)儲存原油(you)(you)(you)(you)(you)(you)、汽油(you)(you)(you)(you)(you)(you)及其(qi)他揮發(fa)性(xing)油(you)(you)(you)(you)(you)(you)品(pin)(pin)。

  浮(fu)(fu)頂(ding)(ding)(ding)罐(guan)的(de)種類很多，有(you)單盤式(shi)(shi)、雙(shuang)盤式(shi)(shi)、浮(fu)(fu)子式(shi)(shi)等。常用的(de)單盤式(shi)(shi)浮(fu)(fu)頂(ding)(ding)(ding)罐(guan)在(zai)浮(fu)(fu)頂(ding)(ding)(ding)周圍建造(zao)環形浮(fu)(fu)船(chuan)(chuan)，用隔(ge)板(ban)(ban)將(jiang)浮(fu)(fu)船(chuan)(chuan)分隔(ge)成若干個不滲漏的(de)船(chuan)(chuan)室，在(zai)環形浮(fu)(fu)船(chuan)(chuan)范圍內的(de)面積以單層金(jin)(jin)屬(shu)板(ban)(ban)覆蓋。而雙(shuang)盤式(shi)(shi)浮(fu)(fu)頂(ding)(ding)(ding)罐(guan)的(de)浮(fu)(fu)頂(ding)(ding)(ding)則是(shi)(shi)上、下兩面分別(bie)以金(jin)(jin)屬(shu)板(ban)(ban)覆蓋。不論是(shi)(shi)單盤浮(fu)(fu)頂(ding)(ding)(ding)罐(guan)還(huan)是(shi)(shi)雙(shuang)盤浮(fu)(fu)頂(ding)(ding)(ding)罐(guan)，浮(fu)(fu)盤上面都安裝(zhuang)有(you)梯子、平(ping)臺和(he)欄桿。建造(zao)浮(fu)(fu)頂(ding)(ding)(ding)的(de)金(jin)(jin)屬(shu)材料有(you)碳鋼(gang)和(he)鋁合金(jin)(jin)兩種，目前(qian)，碳鋼(gang)材料的(de)浮(fu)(fu)頂(ding)(ding)(ding)已逐(zhu)漸被鋁合金(jin)(jin)浮(fu)(fu)頂(ding)(ding)(ding)所替(ti)代。浮(fu)(fu)頂(ding)(ding)(ding)一般在(zai)專門的(de)制造(zao)廠建造(zao)，作為成品(pin)部件供貨。