對開三通主要用(yong)于帶(dai)(dai)壓(ya)(ya)不(bu)(bu)停(ting)(ting)輸(shu)(shu)開孔(kong)(kong)(kong)（hot tap）。帶(dai)(dai)壓(ya)(ya)不(bu)(bu)停(ting)(ting)輸(shu)(shu)開孔(kong)(kong)(kong)是在(zai)不(bu)(bu)停(ting)(ting)產情況下進(jin)行開孔(kong)(kong)(kong)接點，適用(yong)于除氧氣(qi)以(yi)外(wai)的(de)任何介質以(yi)及不(bu)(bu)同直徑的(de)各類管道(dao)。開孔(kong)(kong)(kong)機在(zai)開孔(kong)(kong)(kong)過程中是在(zai)完全封(feng)閉的(de)空(kong)腔內進(jin)行的(de)，刀具切削過程與(yu)空(kong)氣(qi)隔絕，無(wu)著火(huo)、爆(bao)炸的(de)可能性。由于封(feng)閉開孔(kong)(kong)(kong)、無(wu)泄(xie)漏，有(you)毒有(you)害介質不(bu)(bu)能排放到(dao)大氣(qi)中，因此對環境無(wu)污染。管道(dao)不(bu)(bu)停(ting)(ting)輸(shu)(shu)帶(dai)(dai)壓(ya)(ya)開孔(kong)(kong)(kong)、封(feng)堵(du)技(ji)術可避免(mian)作(zuo)業風(feng)險，提高(gao)安全性，使(shi)維修(xiu)既(ji)迅速又經濟可靠。此技(ji)術先進(jin)，設備操作(zuo)簡單，與(yu)停(ting)(ting)產開孔(kong)(kong)(kong)作(zuo)業相比，其經濟效(xiao)益和(he)社會效(xiao)益顯著。在(zai)石油、天然氣(qi)管道(dao)及熱力管線(xian)上均(jun)可帶(dai)(dai)壓(ya)(ya)開孔(kong)(kong)(kong)。典型對開三通見圖(tu)4.6.23。

  對(dui)開三通有(you)關標準規范：API 2201《Safe Hot Tapping Practices in the Petroleum ＆Petro-chemical Industries》；SY／T 6554《石油工業帶壓開孔作業安全規程》。