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。

  浮頂(ding)油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)(guan)當罐(guan)(guan)(guan)(guan)(guan)頂(ding)隨(sui)油(you)(you)(you)(you)面(mian)下降(jiang)至罐(guan)(guan)(guan)(guan)(guan)底時，油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)(guan)就變(bian)為上(shang)部敞開(kai)的(de)立式圓(yuan)筒形(xing)容器，若此時遇(yu)大風，罐(guan)(guan)(guan)(guan)(guan)內易形(xing)成(cheng)真空，如真空度過大罐(guan)(guan)(guan)(guan)(guan)壁(bi)有(you)(you)可(ke)能被壓癟，為此在靠近(jin)頂(ding)部的(de)外側(ce)設置抗風圈。由于罐(guan)(guan)(guan)(guan)(guan)頂(ding)在罐(guan)(guan)(guan)(guan)(guan)內上(shang)下浮動(dong)，故罐(guan)(guan)(guan)(guan)(guan)壁(bi)板只能采用(yong)(yong)對(dui)(dui)接焊接并(bing)且內壁(bi)要(yao)取平。浮頂(ding)油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)(guan)罐(guan)(guan)(guan)(guan)(guan)頂(ding)與(yu)油(you)(you)(you)(you)面(mian)之間基本(ben)上(shang)沒有(you)(you)氣相(xiang)空間，油(you)(you)(you)(you)品沒有(you)(you)蒸發的(de)條件，因(yin)(yin)而沒有(you)(you)因(yin)(yin)環境溫(wen)度變(bian)化而產生的(de)油(you)(you)(you)(you)品損耗，也(ye)基本(ben)上(shang)消除(chu)了因(yin)(yin)收、發油(you)(you)(you)(you)而產生的(de)損耗，避免污染環境，減少發生火(huo)災(zai)的(de)危險性。所以盡管這種油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)(guan)鋼材(cai)耗量(liang)和安裝(zhuang)費用(yong)(yong)比(bi)拱(gong)頂(ding)油(you)(you)(you)(you)罐(guan)(guan)(guan)(guan)(guan)大得多，但(dan)對(dui)(dui)收發油(you)(you)(you)(you)頻繁的(de)油(you)(you)(you)(you)庫、煉油(you)(you)(you)(you)廠(chang)原(yuan)油(you)(you)(you)(you)區(qu)等仍應優先選用(yong)(yong)，用(yong)(yong)于儲(chu)存原(yuan)油(you)(you)(you)(you)、汽油(you)(you)(you)(you)及(ji)其他揮發性油(you)(you)(you)(you)品。

  浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)罐(guan)的種類很多(duo)，有(you)單(dan)(dan)盤式、雙(shuang)(shuang)盤式、浮(fu)(fu)(fu)(fu)(fu)(fu)子式等。常用的單(dan)(dan)盤式浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)罐(guan)在(zai)浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)周圍(wei)建造(zao)環形浮(fu)(fu)(fu)(fu)(fu)(fu)船，用隔(ge)板(ban)(ban)將(jiang)浮(fu)(fu)(fu)(fu)(fu)(fu)船分(fen)隔(ge)成若(ruo)干個不滲漏的船室，在(zai)環形浮(fu)(fu)(fu)(fu)(fu)(fu)船范圍(wei)內的面(mian)積以單(dan)(dan)層金屬板(ban)(ban)覆(fu)蓋。而雙(shuang)(shuang)盤式浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)罐(guan)的浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)則是上、下兩面(mian)分(fen)別以金屬板(ban)(ban)覆(fu)蓋。不論(lun)是單(dan)(dan)盤浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)罐(guan)還是雙(shuang)(shuang)盤浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)罐(guan)，浮(fu)(fu)(fu)(fu)(fu)(fu)盤上面(mian)都安裝有(you)梯(ti)子、平臺和(he)(he)欄桿。建造(zao)浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)的金屬材料有(you)碳(tan)鋼和(he)(he)鋁(lv)合(he)金兩種，目(mu)前，碳(tan)鋼材料的浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)已逐漸被鋁(lv)合(he)金浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)所替代。浮(fu)(fu)(fu)(fu)(fu)(fu)頂(ding)一(yi)般(ban)在(zai)專門(men)的制造(zao)廠建造(zao)，作(zuo)為成品部件供貨。