首先在鋼管上用開孔(kong)(kong)(kong)機(ji)(ji)(ji)開孔(kong)(kong)(kong)，然(ran)后將機(ji)(ji)(ji)械(xie)(xie)(xie)三(san)(san)通(tong)卡入孔(kong)(kong)(kong)洞(dong)，孔(kong)(kong)(kong)四周由密(mi)封(feng)圈沿管壁密(mi)封(feng)。機(ji)(ji)(ji)械(xie)(xie)(xie)三(san)(san)通(tong)分絲接和溝(gou)槽式(shi)兩(liang)種。機(ji)(ji)(ji)械(xie)(xie)(xie)三(san)(san)通(tong)連接時，應(ying)檢查機(ji)(ji)(ji)械(xie)(xie)(xie)三(san)(san)通(tong)與孔(kong)(kong)(kong)洞(dong)的間隙，各部位應(ying)均(jun)勻，然(ran)后再緊(jin)固到位；機(ji)(ji)(ji)械(xie)(xie)(xie)三(san)(san)通(tong)開孔(kong)(kong)(kong)間距(ju)不應(ying)小于1m。

機(ji)(ji)械(xie)(xie)(xie)三(san)(san)(san)通(tong)(tong)(tong)(tong)連(lian)接(jie)方(fang)式廣(guang)泛用于(yu)建筑內的消(xiao)火栓系統(tong)與(yu)(yu)噴淋(lin)(lin)系統(tong)。支(zhi)管接(jie)頭是指(zhi)在直管管道(dao)(dao)中部(bu)開孔后連(lian)接(jie)支(zhi)管的鞍(an)形拼合(he)式連(lian)接(jie)件(jian)，分(fen)為機(ji)(ji)械(xie)(xie)(xie)三(san)(san)(san)通(tong)(tong)(tong)(tong)和機(ji)(ji)械(xie)(xie)(xie)四(si)通(tong)(tong)(tong)(tong)兩(liang)種類型。在設計圖紙(zhi)上一般不會標注出溝槽(cao)(cao)三(san)(san)(san)通(tong)(tong)(tong)(tong)和機(ji)(ji)械(xie)(xie)(xie)三(san)(san)(san)通(tong)(tong)(tong)(tong)的。機(ji)(ji)械(xie)(xie)(xie)三(san)(san)(san)通(tong)(tong)(tong)(tong)或(huo)機(ji)(ji)械(xie)(xie)(xie)四(si)通(tong)(tong)(tong)(tong)與(yu)(yu)支(zhi)管的連(lian)接(jie)方(fang)式有溝槽(cao)(cao)式連(lian)接(jie)和螺紋式連(lian)接(jie)兩(liang)種，當支(zhi)管道(dao)(dao)小(xiao)于(yu)DN50，且主管道(dao)(dao)直徑大于(yu)分(fen)支(zhi)直徑2倍時可用機(ji)(ji)械(xie)(xie)(xie)三(san)(san)(san)通(tong)(tong)(tong)(tong)（直接(jie)在主管道(dao)(dao)上開孔，噴淋(lin)(lin)支(zhi)管與(yu)(yu)主管連(lian)接(jie)用得(de)多），其它情況(kuang)得(de)用溝槽(cao)(cao)三(san)(san)(san)通(tong)(tong)(tong)(tong)。這里的溝槽(cao)(cao)三(san)(san)(san)通(tong)(tong)(tong)(tong)就是正(zheng)三(san)(san)(san)通(tong)(tong)(tong)(tong)（主支(zhi)管中心(xin)線成直角），因為不像(xiang)UPVC管、鑄鐵管除正(zheng)三(san)(san)(san)角還(huan)有Y三(san)(san)(san)通(tong)(tong)(tong)(tong)（斜三(san)(san)(san)通(tong)(tong)(tong)(tong)）、TY三(san)(san)(san)通(tong)(tong)(tong)(tong)。

正(zheng)三(san)(san)(san)(san)通(tong)(tong)與鍍鋅配件的(de)三(san)(san)(san)(san)通(tong)(tong)叫法一樣，只是鍍鋅三(san)(san)(san)(san)通(tong)(tong)是絲扣連(lian)(lian)(lian)接(jie)(jie)，而(er)這(zhe)里正(zheng)三(san)(san)(san)(san)通(tong)(tong)是溝(gou)槽式(shi)連(lian)(lian)(lian)接(jie)(jie)，每個管(guan)(guan)(guan)(guan)(guan)道(dao)的(de)平口端環形溝(gou)槽由專門(men)的(de)滾槽機(ji)(ji)加(jia)工成(cheng)(cheng)型(xing)，與管(guan)(guan)(guan)(guan)(guan)道(dao)連(lian)(lian)(lian)接(jie)(jie)需要(yao)3副相(xiang)應規格卡箍才(cai)能完成(cheng)(cheng)一個接(jie)(jie)頭(tou)，適(shi)合(he)主(zhu)(zhu)干管(guan)(guan)(guan)(guan)(guan)的(de)連(lian)(lian)(lian)接(jie)(jie)。至于(yu)機(ji)(ji)械(xie)三(san)(san)(san)(san)通(tong)(tong)主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)上只需用開孔機(ji)(ji)開孔無需開槽，而(er)支(zhi)(zhi)管(guan)(guan)(guan)(guan)(guan)或開槽（溝(gou)槽式(shi)連(lian)(lian)(lian)接(jie)(jie)）或套絲（螺(luo)紋(wen)式(shi)連(lian)(lian)(lian)接(jie)(jie)），適(shi)合(he)主(zhu)(zhu)支(zhi)(zhi)管(guan)(guan)(guan)(guan)(guan)間的(de)連(lian)(lian)(lian)接(jie)(jie)（如噴(pen)淋系統的(de)噴(pen)淋支(zhi)(zhi)管(guan)(guan)(guan)(guan)(guan)）。另外還有一種小機(ji)(ji)械(xie)三(san)(san)(san)(san)通(tong)(tong)，只是把卡箍換成(cheng)(cheng)了U型(xing)卡，以(yi)我看這(zhe)種小機(ji)(ji)械(xie)三(san)(san)(san)(san)通(tong)(tong)與支(zhi)(zhi)管(guan)(guan)(guan)(guan)(guan)連(lian)(lian)(lian)接(jie)(jie)還是以(yi)螺(luo)紋(wen)連(lian)(lian)(lian)接(jie)(jie)為主(zhu)(zhu)，可(ke)能沒有溝(gou)槽連(lian)(lian)(lian)接(jie)(jie)形式(shi)。正(zheng)三(san)(san)(san)(san)通(tong)(tong)一般(ban)指三(san)(san)(san)(san)個接(jie)(jie)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)(jing)相(xiang)同(tong)而(er)異(yi)徑(jing)(jing)三(san)(san)(san)(san)通(tong)(tong)則三(san)(san)(san)(san)個接(jie)(jie)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)(jing)不完全相(xiang)同(tong)。正(zheng)三(san)(san)(san)(san)通(tong)(tong)用于(yu)同(tong)一直(zhi)徑(jing)(jing)管(guan)(guan)(guan)(guan)(guan)道(dao)連(lian)(lian)(lian)接(jie)(jie)之用，異(yi)徑(jing)(jing)三(san)(san)(san)(san)通(tong)(tong)則用于(yu)不同(tong)直(zhi)徑(jing)(jing)管(guan)(guan)(guan)(guan)(guan)道(dao)的(de)連(lian)(lian)(lian)接(jie)(jie)。機(ji)(ji)械(xie)三(san)(san)(san)(san)通(tong)(tong)連(lian)(lian)(lian)接(jie)(jie)的(de)支(zhi)(zhi)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)(jing)絕(jue)不可(ke)能等于(yu)主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)(jing)。